PETROLEUM

increased consumption and many new uses for petroleum products continuing to stimulate 1924 netherlands east indies 2% 19/3 rumania l% rumania 35% sttien countries 5% netherlands east indies 3% % fic. 1.—the total world production of petroleum in 1924 was about two and a half times that of 1913. these diagrams show the percentage of the total produced by each of the chief producing countries in 1913 and 1924. the search for petroleum in the older producing countries and in new territories, often remote from civilisation, has been rewarded by important extensions and discoveries, with the result that between the years 1908 and 1924 the world’s annual petroleum production nearly quadrupled. this development was largely due to the increased production in the united states. i. the production of petroleum the following table from the u.s. geological survey gives the annual world’s production from 1908 to 1924:-—— barrels of 42 u.s. gal. ; 285,552,746 1917 . 508,687, 302 1909 . 298,616,405 1918 . 514,729,354 igio . 327,937,629 191g . 544,885,000 ioi . 34451745355 1920 . 695,281,000 1ol2) x 352,446,598 t9217. 765,928,000 i9gt3 . 3835471399 {922 . 858,715,000 igl4 . 403,745,652 1923. 1,018,900,000 iqi5 . 427,740,129 1924! . 1,005,915,000 1916 . 459,411,737 gaianted by ou & gas journal, tulsa, okla. petroleum between 1908 and 1925 many prolific fields in the united states were developed, enabling that country to keep its pre- eminent position. mexico, which rose from unimportance to second position during the period of the world war, retained that ranking among oil-producing countries during the post-war period, although total production declined. after 1908, argen- tina, colombia, venezuela, trinidad, egypt and persia devel- oped production of commercial importance, russia added the maikop and ural-caspian fields, and japan the akita prefecture. the production of the various countries in 1923 and 1924 1s : 1923! ool 1924? > of country barrels total barrels total united states . 732,407,000 | 71-9 | 717,000,000 | 71-2 a\lexico 149,585,000 | i4:7 | 140,000,000 | 13:9 russia 39,156,000 3°9 44,000,000 4:4 persia ; 28,793,000 2-8 32,000,000 3-2 dutch east indies . 19,868,000 1-9 15,000,000 1-5 rumania . ; 10,867,000 i'l i 3,000,000 i-3 venezucla 4,059,000 “4 $,200,000 8 india 8,320,000 8 7,500,000 7 peru . 5, 699. 000 6 6,500,000 ‘6 poland (galicia) 5,373,000 5 6,000,000 6 sarawak 3,940,000 “4 4,500,000 “4 argentina 3,400,000 3 4,000,000 ‘4 trinidad 3,051,000 “3 3,750,000 “4 japan and formosa 1,789,000 :2 1,500,000 “i egypt 1,054,000 “i 1,000,000 “i colombia . 424,000 600,000 france 403,000 500,000 germany . 312,000 450,000 canada 170,000 175,000 g zechoslovakia 74,000 “2 100,000 2 italy . 34,000 30,000 algeria 9,000 9,000 england 1,000 1,000 others 112,000 200,000 ————— oe 1,018 ,900,000 1,005,91 5,000 'uls. geological survey. 2 preliminary, oil & gas journal. north america united states —petroleum production in the united states fn 1924 totalled 707,265,000 bar. (net preliminary estimate u.s. geological survey). the following table, from the survey, gives the production of the important divisions in 1908, £933 4 in barrels of 42 u.s. gallons:— district 1908 1923 1924 appalachian 24,946,000 28,225,000 27,049,000 lima-indiana . 10,032,000 2,404,000 2,288,000 illinois and s.w. indiana . 33,686,000 9, 500,000 8,732,000 mid-continent . 48,834,000 | 348,460,000 | 368,729,000 gulf coast ; 15,772,000 | 33,271,000 | 27,642,000 rocky mountain 412,000!| 47,653,000 | 42,761,000 california 44,855,000 seatere 000 230,064,000 178,537,000 | 732,389,000 | 707,265,000 1 including “‘ others.” the appalachian area includes kentucky, west virginia, pennsylvania, new york and eastern ohio. oil and gas sands occur throughout a long stratigraphic interval, including rocks ranging in age from ordovician to carboniferous. petroleum from this area is a high-grade paraffin oil, the average gravity being about 45° baume (o-8000 sp. gr.). the lima-indiana field covers northwestern ohio and northeastern indiana, the oil being obtained from lenses or discontinuous layers in trenton limestone. the average gravity is about 39° baume (0-8285 sp. gr.), although some of the oil is much heavier. the principal productive area in the illinois field is in the southeastern part of the state, but there are also scattered pools in central and western illinois. most of the oil is obtained from beds of sand- stone in the pennsylvanian and mississippian series of the carboniferous system. in gravity the oils range from 27° to 37° baume (0-8917 to 0-8383 sp. gr.). petroleum the greatest increases in production between 1908 and 1924 occurred in the mid-continent field, embracing oklahoma, kansas, northern, central, eastern and southwestern texas, northern louisiana and southern arkansas. pools are scattered throughout the area and new pools are constantly being dis- covered. most of the oil is obtained from sandstone or other porous rocks of the cretaceous and tertiary systems. the average oil has a gravity of about 35° baume (0-8485 sp. gr.), ranging from the thick black oil of some of the louisiana and arkansas fields, of 21° baume (0-9272 sp. gr.) or under, to the high grade cushing oil of above 55° baume (0-7568 sp. gr.). the glenn pool discovery in creek county, okla., in 1907 led to a great petroleum development in that state, the pool reaching a maximum production of 125,000 bar. a day. in 1912 the cushing pool, also in creek county, was discovered; the maxi- mum production reached was 320,000 bar. a day, sustained for a 60-day period in 1914, and resulting in the collapse of the oil markets. in 1914 the augusta pool in butler county, kan., was opened up, and in tors the el dorado pool, also in butler county; with the towanda extension, the latter pool made over 100,000 bar. for a few days in sept. 1917. late in 1917 the discovery of oil in a well 3,450 ft. deep near ranger, in central texas, resulted in a most sensational develop- ment, covering the widest “‘ boom ” area in the history of pe- troleum in the united states up to that time. the ranger boom is significant in two main respects: it began a long series of great ‘‘ wildcat ” enterprises, the testing out of great areas of unproven oil lands, the results of which were still felt throughout the next decade; and it was the beginning of the movement on the part of american oil operators to drill deeper and deeper for possible oil sands, which was responsible for great volumes of the new production that has been developed. the ranger development opened up extension pools in eastland county, stephens county, and adjoining counties. in july 1918 a pro- lific well opened up the burkburnett pool development in northern texas. another important development in the mid- continent field was the discovery in sept. 1918 of oil in a shallow well near homer, in northern louisiana: a large gusher at greater depth was brought in in aug. rgro. one of the most important developments of the early part of 1921 was the discovery of oil in commercial quantity in south- ern arkansas. the el dorado pool in union county resulted. the mexia pool in limestone county, tex., was developed in 1921. the “ flush”? production pendulum swung back to oklahoma later in 1921, and in 1922 important extensions and discoveries resulting from deeper drilling occurred, the output of the state being chiefly increased by such pools as the burbank, bristow, hewitt, lyons-quinn and tonkawa. but the greatest succession of flush pools reaching their peak in the mid-conti- nent field in conjunction with similar pools in california was in 1923, when burbank and tonkawa in oklahoma, the original smackover development in arkansas, and the powell field in eastern texas, all in the mid-continent area, attained high pro- duction levels. in 1924 oklahoma’s bonanza pools showed little loss in production, burbank was extended, and a prolific deep sand development occurred in the tonkawa field. the smack- over pool in arkansas was extended and production greatly increased. the sensational and short-lived wortham pool in eastern texas came in dec. 1924. several smaller pools, which in combination resulted in considerable new production, also came in during 1924 in oklahoma. the gulf-coast field first came into prominence in 1901, when the spindletop pool in jefferson county, tex., was developed. this field includes southern texas and southern louisiana, and the petroleum is associated with masses of rock salt and gypsum in domes. the age of the oil-bearing strata ranges from cre- taceous to quaternary. the field includes a great number of small scattered pools, some of which have developed wells of enormous productivity. the gravity of the oil ranges from 15° to 30° baume (0-9655 to 0-8750 sp. gr.). among the more important pools are the goose creek, hull, humble, west columbia and damon mound pools. the rocky mountain 93 field, which embraces the areas of production in colorado, wyoming and montana, as well as new producing and pros- pective territory in utah, arizona and new mexico, was being tested by the oil driller in 1925 with good results; the greatest development was in the salt creek field of natrona county, wyoming. the most sensational developments were in california, where oil production during the five years preceding 1922 had been running from 100,000,000 to 115,000,000 bar. annually. before 1923 the principal producing districts were kern river, mckit- trick, midway-sunset, lost hills and belridge in kern county; the coalinga field in fresno county; the lompoc and santa maria fields in santa barbara county; the ventura and newall fields in ventura county; and the los angeles and salt lake and whittier-fullerton fields in los angeles county. the bulk of the production was heavy oil averaging about 21° baume (o-9272 sp. gt.). important addition to production in the mid- way-sunset field was made in 1920~1 by the development of the elk hills district. but the most important discoveries were in 1920 of the huntington beach field, and in 1921 of the santa fe springs and long beach fields, all in the los angeles basin. these fields reached their greatest production in 1923, and yielded high-grade, gasolene-bearing crude oil. the production in barrels of the major pools in 1923-4 is shown in the following table, taken from ‘“‘ world production of petroleum in 1924’ by e. de golyer, transactions of american institute of ‘mining and metallurgical engineers:— field 1923 1924 california: huntington beach 34,355,000 17,533,000 long beach . ; 68,810,000 60,122,000 santa fe springs 79,781,000 26,309,000 total 182,946,000 103,964,000 wyoming: salt creek 33,645,000 30,879,000 oklahoma: burbank 33,821,000 30,805,000 tonkawa 27,033,000 22,413,000 total 60,854,000 53,218,000 arkansas: smackover 35,041,000 42,000,000 texas: powell 32,243,000 33,374,000 total 344,729,000 263,435,000 by the end of 1924 california’s three great pools had declined in production or showed signs of considerable decline, but con- siderable production was added in the los angeles basin district by the torrance, dominiquez and rosecrans pools, and early in 1925 by the inglewood pool. alaska.—oil has been found in several localities in alaska, notably in the katalla field: in the kayak field, several miles inland from cape suckling; in the cook inlet field, between itimma peak and ihamna lake; and in the cold bay field, opposite kodiak islands. wells were drilled in the early ’nine- ties in the kayak, cook inlet, and cold bay regions, but oil was not found in commercial quantity. desultory search for oil in alaska has continued. in 1923 the associated oil co. and the standard oil co. (california) drilled wells in the cold bay field without any favourable results being reported. canada.—canada’s production has declined since 1908. the output in 1924 was estimated at 175,000 bar., compared with 528,000 bar. in 1908. virtually all of canada’s petroleum is pro- duced in ontario, and occurs in sandstone and limestone of silurian and devonian age. a small production is obtained in new brunswick and alberta. in 1920 oil was discovered on the mackenzie river, 150 m. south of the arctic circle in the cana- dian north-west territory. the well was located northwest of fort norman, and on aug. 23 1920 it began to flow over the 94 top of the mast from a depth of 783 ft.; after an uninterrupted flow of 40 min. the well was capped. in 1922 the well was leepened to g51 ft., with the result that a flow of 60 to 70 bar. per day was secured; it was again deepened in 1923 and the flow was increased to about 100 bar. aday. two other wells were drilled in 1923 with negative results. during the summer of 1924 another well, 150 ft. east of the discovery well, was started and carried down to 975 ft., with an oil showing at that depth, and the test is being continued. in the autumn of 1922 oil was struck at wainwright, 120 m. southeast of edmonton, in alberta. this has stimulated drilling in the wainwright-irma district. in 1924 a well producing oil of 73° baume was brought in in the turner valley field, 45 m. southwest of calgary. it blew itself in on oct. 14 and is stated to have produced at the rate of 400 bar. daily, with production steadily increasing. mexico.—mexico’s petroleum development, sensational in its rapid growth, has been, when considered from the view-point of individual wells and leases, equally sensational in its rapid decline. mexico still ranked second among the world’s pro- ducing countries in 1925, but its ‘* golden lane ”’ of the so-called southern field or tampico-tuxpam region, which supplicd the bulk of the oil in the years 1919 to 1922 inclusive, has virtually been exhausted except for “ stripping ’’ operations. however, the northern or panuco fields have done much to offset these losses. an interesting feature of the change that has occurred in mexican petroleum relates to the fact that in the southern area the oil is so-called “ light ” oil, ranging from 15° to 290° baume (0o-9655 to 00-8805 sp. gr.), while in the northern area the oil is ‘‘ heavy,” ranging from 10° to 14° baume (1-000 to 0:9722 sp. gr.). thus the losses in production have been in the more valuable light oil. mexican production in 1924 is estimated at 140,000,000 bar., which compares with 149,585,000 bar. in 1923 and 182,266,000 bar. in 1922. the change in the volume of light and heavy oil from 1922 to 1924 is shown in the following table:— light total hleav i. barrels barrels carrels | 1922 i 36,505,000 45,761,000 | 182,266,000 1923 61,043,000 88,542,000 | 149,585,000 1924. : 35,500,000 | 104,500,000 | 140,000,000 although yielding oil as early as 1901, it was not until 1910 that production of mexico became a commercial factor. in the latter part of that year the juan casiano no. 7 well was drilled south of the dos bocas well, the latter an uncontrolled gusher south of tampico, struck july 4 1908, which went to salt water several months later. the potrero del llano no. 4 well came in dec. 27 1910, with an estimated initial flow of 10,000 bar. daily, increasing to 160,000 bar. and establishing itself as the largest producer up to that time. both the casiano and del llano wells were in the so-called southern field as distinguished from the northern or panuco field, these two fields being part of the tampico-tuxpam region. this lies in the northern part of the state of vera cruz and the southern part of the state of tam- aulipas. oil in the tampico region occurs in the oligocene, eocene, and cretaceous formations, and is found in numerous pools. before striking the big wells mentioned a considerable production had been developed at ebano, 40 m. west of tampico, in the northern part of the tampico-tuxpam area and in the tehuantepec area. the tehuantepec-tabasco arca extends along the gulf coast in southern vera cruz and the state of tabasco. its oil-bearing rocks are of the pliocene and pleistocene age, and it had not developed a large production up to 1925. oil in the tehuantepec field has a gravity of 32° baume (0-8642 specific gravity). central and south america no petroleum production has been developed in central america, but prospecting has been done and some drilling was under way in 1924-5. test wells have been sunk on columbus island, off the east coast of panama, and in the estrella valley of costa rica. exploration work has been done in honduras and guatemala. petroleum argeniina.—argentina’s commercial production dates from 1908. late in 1907 petroleum was found ina well being drilled for water by the government near comodoro rivadavia, chubut province, on the coast of patagonia. the government immediately reserved part of the oil-bearing land, and argentina’s petroleum development has thus been in large part in the hands of the government, although in recent years private companies have been active both on govern- ment lands and on privately held lands. argentina’s oil production is estimated at 4,000,000 bar, in 1924, compared with 3,400,000 bar. in 1923, and slightly over 1,000,000 bar. in 1919. innumerable in- dications of oil, asphalt, rafaelite, etc., occur throughout the whole length of the country. heayy oil is found seeping out near punta arenas on the straits of magellan, in the beds assigned to the tertiary period, but no systematic prospecting operations have been carried out. the most southerly wells are drilled in the neigh- bourhood of santa cruz, but the results recorded are of a discourag- ing order. from comodoro rivadavia the oil belt extends north- ward through the territory of neuquen and the provinces of mendoza salta and jujuy, to the bolivian border, a distance of about 1,500 m., the width being unknown. broadly, the oil-bearing formations ex- ploited belong to the cretaceous at comodoro rivadavia, the upper jurassic in the province of neuquen, the triassic (rhaetic) at mendoza, and range from upper mesozoic to the devonian in jujuy and salta. most of the production since the beginning of operations in argentina has come from the comodoro rivadavia ficld. the oil is heavy and of asphalt base, and ranges in gravity from 18-9 to 21°8° baume (0-940 to 0-922 sp. gr.). argentina in recent years has seen great prospecting and development activity and has great potentialitics. venesuela.—active prosnecting in venezuela began in i9g10, and during the next four or five years wells were drilled in several areas with varying success. a well in the mene grande field, on the east coast of lake maracaibo, sucre district, drilled in 1913, established the occurrence of oil in paying quantity, and by 1915 the field had developed a considerable production, furnishing up to 1921 prac- tically all the venezuelan output. drilling in the district of colen, state of zulia, commenced in 1914. four wells credited as good pro- ducers in the rio oro and rio ‘tarra sections had been completed by 1916 and were shut in. two wells reported as proven in the bolivar district, state of zulia, were also capped. operations in venezuela in 1920-1 were active, particularly in the lake maracaibo district. during the period 1921-5 several important fields have been added to venezuelan producing territory. in 1924 the estimated production was 8,200,000 bar., compared with 4,059,000 bar. in 1923. commercial production in the mene grande field dates from 1917 and has steadily increased. the field is located about 75 m. southeast from the city of maracaibo on the eastern side of lake maracaibo and about 12 m. from the shore. the oil is a heavy oil. in the la rosa field, located on the east side of the lake about 27 m. southeast of the city of maracaibo, the first drilling was done in 1915, but after the completion of two smal} wells operations were virtually discontinued until 1922, when the la rosa gusher, which produced over 1,000,000 bar. in nine days before it sanded up, was brought in. competitive producing with many wells drilled in the lake adjacent to the shore has been a feature of the la rosa develop- ment, which has recorded many large wells, practically all of which have experienced difficulties in sanding up and which, therefore, are being pinched down to reduce the pull on the sand. in 1925 la rosa was the largest producing field in venezuela, the oil is a heavy oil. another field which has attained commercial production is el mene, which is located in the northeastern semi-arid part of the maracaibo basin and about 36 m. inland from the lake. the oil is a light oil, and the wells, which are comparatively shallow, are not of the large volume, gusher type. the la pazand concepcion fields, about 15 m. apart, are located on the west side of the lake. both fields have been proven and further drilling is in progress, while exploratory drilling throughout venezuela is occurring. colombia.—colombia is one of the recent arrivals in the oil-pro- ducing columns, and in 1924 was credited with an output of 600,000 bar., compared with 424,000 bar. in 1923. the principal develop- ment and the only one on a commercial scale is that of the infantas field, on the de mares concession, located on the rio colorado tn santander del sur. the field is approximately 350 m. from the mouth of the magdalena river. at the end of 1924 there were 17 producing wells in the field, some of them shut in. preliminary work was started in 1925 for laying a pipe line from the field to the coast. other test work with varying results has been carried on. oil from the infan- tas field is reported to test 26° to 31° baume (0-8974 to 0-696 sp. gr.). peru.—peru is the oldest oil-producing country in south america, first being credited with production in 1896. its production has been steadily maintained, the principal fields being negritos, lobitoa and zorritos. another petroliferous district near lake titicaca has not developed any considerable production. oil is found chiefly at the north (pacific coastal district), and occurs in several horizons of soft sandstone and shale of early tertiary age. the oil ranges from 32° to 48° baume (0-8642 to 0-7865 sp. gr.). production has steadily increased, and in 1924 the output was credited at 7,500,000 bar., compared with 1,011,180 bar. in 1908. this does not represent maximum production, as much production was shut in during 1924 owing to the depression of the world’s oil markets. the bulk of the petroleum output comes from the negritos field, which in 1924 produced ap- proximately 6,500,000 barrels. prospecting in other staies.—bolivia and ecuador have been actively prospected, but oil in commercial quantity has not been developed. chile has had several oil booms, particularly those based on the oil deposits of the province punta arenas, northwest of ticrra del fuego, but without successful results. prospecting has been undertaken in brazil and uruguay. the west indies trintidad.—the oil-fields of trinidad are mainly in the southern part of the island, the oil being obtained from lenses of sandstone of tertiary age. trinidad first appeared as an oil producer in 1908, although in 1902 wells were known to exist north of the pitch lake at guayaguayare, in the extreme southeast of the island. this dis- trict became prominent in 1908, when a well at 700 ft. spouted oil over the derrick, and a rapid development followed. oil in the pitch lake district varies in density from 14° to 25° baume (0-9722 to 0-9032 sp. gr.). in the latter part of 1911 regular oil shipments from brighton began. in that year several large gushers were brought in, but immediately clogged, owing tosand. in 1913 a well came in rated at 40,000 bar. daily, but sanded up, and in subsequent years other large producers have been reported, the initial production of which has soon fallen off on account of sand. trinidad’s production in 1924 totalled 3,750,000 bar., compared with 3,051,000 bar. in 1923. cuba.—an oil boom in cuba in 1917 failed to yield any consider- able production. the principal development was in a field near havana. prospecting and a little drilling work have been done in santo domingo and exploration work carried on in barbados and in haiti. europe russta.—while russia, as a result of the world war and the revolution that followed, dropped in world rank as regards petroleum production, it remained the largest european producer. oil is found in tertiary clays and sands. baku oils are of about 27° baume (0-8917 sp. gr.), while in the suraghany district of baku province the oil is as high as 48° baume (0-7865 sp. gr.). the relatively small area comprising the baku field supplies the bulk of russia's produc- tion. other productive fields are the grozny, maikop, ural-caspian (emba), and cheleken fields. the maikop field in the province of kuban on the north flank of the caucasus, northeast of the black sea, was discovered in 1910. maikop oil is about 4o° baume (0-8235 sp. gr.). the ural-caspian held, covering a large area in the emba- uralsk region round the north end of the caspian sea, first became a commercial factor in 1913. emba oil is about 28° baume (0:8861 sp. gr.). for many years the island of cheleken—off the asiatic coast of the caspian sea near krasnovodsk, was the scene of moder- ate operations, and from i9ii onwards large yields were obtained from wells sunk in the ali tepe district in the southwest. cheleken oil its about 22° baume (0-9211 sp. gr.). the russian revolution disorganised the oil industry. production was 72,801,110 bar. in 1916, but it had dropped to 25,429,600 bar. by 1920. in may 1921 the industry was nationalised and was then built up at a fairly steady rate to a production of about 44,000,000 barrels. soviet officials reported that in the early part of 1925 produc- tion was attaining pre-war level. galicia (poland).—galician production showed a declining tend- ency after 1909, and during the world war the decline was aggravated, as the flelds were battlegrounds. the largest output is obtained from eocene beds. the chief producing areas are: in eastern galicia, boryslaw-tustanowice, and bilkew; in western galicia, bobrka, potok and the gorlice district. the bulk of galicia’s production comes from the boryslaw-tustanowice district. boryslaw ail is 32° to 34° baume (0-8642 to 0-8537 sp. gr.), and is the standard market grade for galicia. bitkow oil is about 53° baume (0:7650 sp. gr.); bobrka, about 31° baume (0-8696 sp. gr.), potok, 34° to 45° baume (-08537 to 0-8000 sp. gr.). production in 1924 was approximately 6,000,000 bar.; the peak of production was in 1909 with 14,932,799 barrels. rumania,—like galicia, a battleground during the world war, rumania suffered in petroleum production. most of the oil is ob- tained from miocene and pliocene beds, but part is from eocene and oligocene and possibly from cretaceous beds. the principal fields are bustenari, campina, moreni, filipesti, baicoi, and buzau. the oil is from 25° to 45° baume (0-9032 to 0-8000 sp. gr.). production in 1924 was 13,000,000 bar. and had practically reached the maximum output prevailing before the world war. germany.—oil is obtained largely at hanover, where it occurs in domes associated with rock salt. the rocks are chiefly limestone and sandstone of upper jurassic age. oil at shallow depths is heavy, gravity from 17° to 19° baume (60-9524 to 0:9396 sp. gr.); at greater depths the oil is lighter. the production is very small. france.—production in alsace occurs in sandstone of eocene and oligocene age and is comparatively small. the gravity ranges from 25° to 29° baume (0-9032 to 0-8805 sp. gr.). | jtaly.—italy’s production, relatively small, is chiefly in the emilia district of lombardy, on the northeastern slope of the apennines. oil occurs in sandstones of focene and miocene age, and ranges from 31° to 48° baume (0-8696 to 0-8187 sp. gr.). 95 great britain.—apart from the shale-oil industry of scotland and wales, great britain joined the list of petroleum-producing coun- tries in 1919, when the hardstoft well was brought in in derbyshire. this was one of 11 drilling locations, seven of which were in derby- shire, two in north stalfordshire and two in the midlothian district - of scotland. the hardstoft well was started in oct. 1918 and struck oilin may 1919, at 3,078 feet. at 3,100 ft. it produced 10 or 11 bar. daily. ‘the well was still overflowing naturally at the end of 1920. up to that time its production totalled 4,575 bar., or 590 tons, of which 2,909 bar., or 375 tons, were produced in ig20. after 1920 production declined, other test wells have failed to develop a com- mercial production. oil from the hardstoft well tested 40° baume (0-8236 sp. gr.). a considerable production of petroleum is derived from the scottish shale-oil fields stretching from dalmeny and abercorn on the firth of forth southward to the district of cobbinshaw and tarbrax. the oil-shale industry in scotland has been in commercial operation since 1850; in 1917, 3,116,529 long tons of oil were pro- duced. there is a small oil-shale production in england and wales. africa egypt.—prospecting in egypt resulted in the discovery of oil on the borders of the red sea and the development of small production in 1911. in 1913 several large wells were brought in in the gemsah district on the west shore of the red sea, near the junction of the red sea and the gulf of suez. in oct. 1914 oil was struck in the hurghada district, south of gemsa, and up to 1925 egypt's produc- tion had been mainly confined to these districts. the oil occurs in sandstone and in cavernous, dolomitic limestone, associated with thick beds of gypsum of miocene (tertiary) age, accompanied in some places by thick beds of salt. the underlying nubian (creta- ceous) sandstone also contains some oil. egyptian oil is about 40° baume (0:8235 sp. gr.). difficulties from salt-water flooding have been encountered in the fields, shortening the life of the large wells. exploitation has been restricted to a comparatively small area, but exploratory work has been carried on in other areas. while egypt’s production almost doubled in 1918 as a result of increased activities that year, it fell off in 1919, and in 1920 showed a sharp decrease. production in 1918 was 2,079,750 bar.; in 1919, 1,501,000; and in 1920, 1,042,000. from 1920-5 production failed to increase. other areas.—some oil has been obtained in the shelif river area in the district of oran, algeria. over 30 wells have been drilled in the msila and mejila districts, but during the world war operations were practically discontinued. interest in algeria revived after the war. the oil-bearing formation is probably upper miocene and its structure is complex. prospecting has been active in angola and ashanti, in the tertiary coastal plain formations, and tests have been drilled in angola in the alto daude district near loanda and at ambrizette. showings of oil were reported in test wells drilled in the betsiriry valley, madagascar, but no commercial production developed. asia persia.— persia is looked on asa new petroleum-preducing country of unusual importance. development has been virtually confined to the maidan-i-naftun field in northern ‘arabistan, about 100 m. north of the head of the persian gulf, where the first wells were completed in 1908. in 1914, 10 wells were reported as being operated, and 20 more were shut down at the top of the sand. in the neigh- bouring maidan-i-naftek field one well had been drilled and capped and a second begun. one test well had started in the white oil springs district. the following year a total of 12 wells had been completed in the maidan-i-naftun field. the oil is rich in naphtha content. the entire persian production up to 1925 was from flowing wells of the maidan-i-naftun and nearby pools, all controlled by the anglo-persian oil co., ltd. in his report to the general meeting of the company tn london on nov. 25 1924, the chairman stated that production from the persian fields was then at the rate of 4,500,000 tons (34,650,000 bar.) per year—the maximum quantity that they were then able to dispose of, and that much production was closed in. he further stated that the company's production could be brought up to 10,000,000 tons (77,000,000 bar.) per annum by opening all existing wells, and that it could be further augmented within a few months by drilling in wells that had been carried only to the cap rock. well f7, in the maidan-i-naftun field, maintained a flow of over 11,000 bar. daily from its discovery in nov. igii, and is reported to have produced about 6,000,000 tons (46,200,000 bar.) up to 1925. in addition to the maidan-i-naftun field, the ahwaz pusht-i- kuh, qishm island and the persian gulf regions are expected to yield petroleum. ‘irag.—there are several petroliferous areas in the tigris-euphra- tes basin, primitive development has yielded some oi) in the kirkuk- mandali-qasr-i-shirin area north of baghdad, in the middle tigris belt and in the euphrates belt. large-scale development of the fields was interrupted by the war, but interest in them was revived during the post-war period. palestine.—the first drilling for oil in palestine, southwest of the dead sea, was interrupted by the war. prospecting had previously been active in the area between the river jordan and dera‘a, ad- jacent to the hejaz railway, 96 india.—the principal source in india is the yenangyaung field in burma, about 272 m. north of rangoon on yenangyaung creck, other important districts are the singu, minbu, pakokku and upper chindwin. the oil is in rocks of miocene age and is about 30° baume (0-8750 sp. gr.). deep drilling was a feature of the development in this field after 1914. some wells came in with a jarge initial flow, but fell off rapidly owing to the intense development of the territory. coal-bearing rocks of eocene age have yielded oil in small quantities in assam and in the punjab. india’s production in 1924 was estimated as 7,500,000 bar., representing a substantial de- cline from its peak year. japan and formosa.—japan’s principal oil production fs found in the echigo province field. since 1908 the most important develop- ment has been in akita prefecture. the first gusher was drilled in this field in may 1914, flowing at the rate of 12,000 bar. daily. many other large wells have been developed. the akita gushers have de- clined rapidly. oil 1s obtained from coarse sandstone layers, inter- stratified with sandy shale of tertiary age. the oil is about 25° baume (0-9032 sp. gr.).. a small production is also obtained in formosa. production of japan and formosa in 1924 was estimated as 1,500,000 bar., representing a substantial decline from the peak. china.—a joint investigation of petroleum resaurces in the prov- inces of shensi and chihli was undertaken in 1914 by the chinese govt. and a private corporation. drilling of six wells began in the yenchang field, shensi, where previously a number of primitive wells had been put down and a small production obtained. in 1916 the abandonment of the enterprise was announced. no oil in com- mercial quantity was struck. oceania and the east indies dutch east indies.—production of petroleum in the dutch east indies has shown a steadily increasing tendency. production is ob- tained in sumatra, borneo and java. most of the oil-bearing rocks are associated with beds of coal and lignite of miocene age. oil of the langkat district of sumatra has a gravity of 33° to 55° baume (0-8589 to 0-7692 sp. gr.). java oil is heavier, ranging between 23° and 40° baume (0-9150 to 0-8235 sp. gr.). borneo oils from shallow wells have a gravity of about 14° baume (0-9722 sp. gr.), and from the deeper wells a gravity of from 27° to 33° baume (0-8917 to 0-8589 sp. gr.). production of the dutch east indies, including a small production from british borneo, was 10,500,000 bar, in 1924. papua.—test drilling has been undertaken in papua, and, while oil has been struck, difficulty has been caused by mud clogging. __ philippine islands.—prospecting and drilling work started in the philippine islands in 1920 in the bondoc peninsula district. austratasia,—extensive prospecting and drilling work have been done, especially in new zealand in the vicinity of new plymouth, in south australia, in the robe district, and in queensland, in the roma district. exploitation in these districts has failed to develop petroleum production in commercial quantity. new south wales has developed an oil-shale production amounting in 1922 to 32,489 tons, which, however, fell to 23,467 tons in 1923. ii. growth of the industry oil in the world war.—petroleum was of vital importance in industrial, military and naval operations during the world war. industrial plants required abnormally large quantities of lubricating oils and fuel oils. there was a rapid growth in the numbers of oil-burning ships, and a new demand for petroleum was made by aircraft, by the introduction of petrol-burning motor-launches, by tanks used in military operations, and by the creation of the motor transport. in all the belligerent coun- tries special departments were organised to handle petroleum problems, and drastic restriction of home consumption was enforced. the inter-allied petroleum council, consisting of representatives of great britain, the united states, france and italy, was formed in 1917, and arranged for the requirements of each of the allics and for the transportation of the petroleum allotted. america supplied 80% of the allied petroleum require- ments. the transportation of these great quantities necessitated large additions to tanker fleets, particularly those of great britain and the united states. in 1918 there were 2,628,961 tons of fuel oil alone shipped from the eastern seaboard of the united states for the use of the allied navies. in the same year more than 1,000,000 tons of distillates and other petroleum products also crossed the atlantic, entailing more than soo tank steamer loadings. war-needs also brought a realisation of the value of petroleum products, and extensive investigations into possible substitutes were made. financial and industrial progress—the expansion of pe- troleum activity involved a great increase in financial require- ments. while the tendency was towards consolidation and the petroleum perfecting of large organisations, there was also, particularly in the united states, an extraordinary growth of smaller com- panies, some of them embracing all fields of petroleum enter- prise. the standard oil and royal dutch-shell groups are outstanding examples of world-wide petroleum operations, and the anglo-persian oil co., which originally confined its operations to persia, expanded them to other fields to include all phases of petroleum activity. the original standard oil trust, following prosecution under the sherman anti-trust law, was broken up in 1911 into 33 companies, most of which were operating before as separate entities. probably the most progressive of these companies, apart from the parent new jersey company, is the standard oil co. (indiana) which in 1925 acquired a dominat- ing interest in the pan-american petroleum and transport co., with principal producing properties in mexico and with a dis- tribution business for fuel oil and other products in many parts of the western ilemisphere and in europe. in 1909 the approximate investment in the oil industry in‘ the united states, tankage, refineries, pipe lines, tank cars, tank steamers and marketing equipment—was $800,000,- ooo. in jan. 1926 it was nearly $9,000,000,000, divided approxi- mately into production $4,500,000,000, refineries $2,300,000,000, pipe lines $700,000,000, tank cars §270,000,000, marketing equip- ment $800,000,000, and tank steamers $430,000,000. much of this expansion is attributable to the automobile, which has completely revolutionised the oil industry. in 1909 there were 311,000 automobiles registered in the united states: at the end of 1924 there were 17,600,000 depending upon the petroleum industry for gasolene and lubricating oil. . in 1924 the production of crude oil in the united states was 714,000,000 bar. and 78,000,000 bar. were imported, as against 128,000,000 bar. produced and an insignificant quantity im- ported in 1909. ‘there were 357 refineries with a daily crude oil capacity of 2,481,000 bar. operating at the end of 1924, as against 147 refineries with a daily capacity of probably less than 500,000 bars. in 1909. the output in barrels of products by refineries in 1924 compared with 1909 was as follows:— 1924 1909 gasolene 21 3,000,000 i 4,000,000 ixerosene : 60,000,000 46,000,000 gas and fuel oils 320,000,000 40,000,000 lubricating oils 28,000,000 i 3,000,000 note: figures from u.s. bureau of mines. the great increase in the use of gasolene was accompanied by an increase only slightly less momentous in the use of fuel oil. the navies of the great powers began to use fuel oil shortly before the war, which made the conversion from coa} almost complete, and, further, brought about the use of oil by fast passenger and cargo vessels. on june 30 1925 world oil-burning vessels (including motor ships) of soo gross tons and over totalled 3,822, aggregating 19,372,615 gross tons, compared with so1 ships, totalling only 1,721,747 tons, registered in 1914.1 the growth of the motorship, or the internal combustion diesel and semi-diesel engined ship, requiring a petroleum fuel oil, was the most pronounced development in shipbuilding from 1923 to 1925. in the united states fuel ot! is in fairly general use under boilers in industrial plants. a new and growing use is in household burners; many types of these, however, burn a kerosene distillate called furnace oil. in 1925 the approximate annual consumption of gas and fuel oil in the united states was: by railroads, 63,000,000 bar.; merchant vessels, 55,000,000 bar.; united states navy, 6,000,000 bar.; electric plants, 17,000,000 bar.; gas manufacturing plants, 23,000,000 bar.; and industrial plants and homes, 128,000,000 barrels. naiionalisation.—nationalisation of oil-bearing lands, 7.¢., the retention or vesting of ownership of subsoil rights in the hands of the state, has been a pronounced tendency in certain countries. in russia, petroleum lands were nationalised and are operated by the sovict government. argentina’s petroleum development has been al- most entirely in the hands of the government. in may 1917 a new mexican constitution provided for the nationalisation of petroleum, ' lloyd’s register and the u.s. bureau of navigation. petroleum specifically art. x xvii. and various decrees were promulgated in the attempts to carry out the nationalisation principle. several efforts were made by the mexican congress to pass a petroleum code interpreting art. xanvil., and in 1925, such a bill was passed by congress. in other latin-american countries nationalisation is generally adhered to in working out petroleum codes. direct government interest in petroleum development was brought about in great britain by the action of the british govt. in becoming a majority shareholder in the anglo-persian oil company. rumania in 1924 adopted and was putting into effect a new mining law which provided for the nationalisation of the oil industry. federal petroleum legislative activity in the united states has never gone so far as serious advocacy of nationalisation. in feb. 1920 a general leasing bill was passed by congress as a relief measure and as a means of practical handling of lands which had been with- drawn from public entry, including large naval oil reserves. in june 1920 there was further enactment giving the secretary of the navy powers covering leasing and operation of the naval reserves. in may 1921 a presidential decree authorised transfer of the admin- istration of the naval reserves from the secretary of the navy to the secretary of the interior. the withdrawal of public lands was a conservation measure developed as part of president roosevelt's broad conservation programme. late in 1924 president coolidge appointed a federal oil conservation board, comprising the secretaries of interior, war, navy and commerce, to study the government’s responsibility with regard to the conservation of oil. the american petroleum institute committee on conservation made an exhaustive study of the petroleum resources of the united states and of the future demand for petroleum, and rendered its report to the federal oil conservation board in aug. 1925. the committee found no imminent danger of exhaustion of the petroleum resources of the united states. ill. technical developments finding oil.—the principal advance in the geological technique of oil finding is along the line of improvement in subsurface correlation by means of foraminiferal studies, additions to the knowledge of which are being made slowly but surely, and by means of mineral, and especially heavy mineral, determinations in well samples. the general application of geophysics by means of torsion balances and seismographs, has proven the greatest new aid to geology. the physicist has offered in these two types of instruments which will permit, under special conditions, the location of salt domes, faults and anticlines. there are three types of torsion balances—eotvos, bamberger and oertling—but all are essentially the same as the original eotvos in principle, varying only in portability, sensitiveness and the presence or absence of a self-recording photographic attachment. these instruments give the differential in millionths of the density of adjacent portions of the earth's surface. vhus beds of a higher density below one part of the surface, as in the case of limestone- anhydrite capped salt domes, may be distinguished from those of lower density such as ordinary unconsolidated sediments, surrounding them. the seismograph attempts to make usc of an entirely different principle—that of the differentiated velocities of pressure waves, refracted through different rock masses, such pressure waves being actuated by the explosion of a small charge of dynamite (one to two hundred pounds) at or slightly below the surface, and the recording of such waves, usually photographically, by means either of one of two general types of seismographs—mechanical and galvanometric. drilling systems.—the principal drilling systems are: (1) percus- sion, which includes the standard cable tool (american system) and the pole tool (canadian system); (2) hydraulic rotary system; (3) combination system; (4) hydraulic circulating system (see 21-319). though differing in design and construction, the several drilling outfits have many features in common. regardless of the method or system employed, the power plant generally consists of a portable boiler, capable of developing from 30 to 70 ti.p. and a standard type of horizontal steam engine of from 20 to 50 horsepower. well depths range froma few hundred feet to over 6,000 ft., the deepest producing wells being in california. deeper drilling in the united states has accounted for much of the greatly increased production. a well of average depth in the mid-continent field could be drilled and equipped for less than $13,000 in 1913. in 1915 the cost increased to about $14,000; in 1918 to $24,000; in 1920 to $30,000 and in 1925 to about $35,000 or $40,000. in mexico, where the wells usually have a great initial production and where the yield of individual wells is often restricted only because of inadequate marketing facilities or as a precaution against water inroads, the percentage of current pro- duction that might be termed “ flush ” is much higher than in any other producing country. the canadian pole tool system is used in canada, while the deeper drilling in the calgary district has been done by the standard cable system, and there has also been some rotary drilling. the standard cable system is principally used in venezuela, although there has been a good deal of drilling with the rotary method and a combina- tion of both. wrells in colombia have been drilled by the cable system and combination cable and rotary. the standard cable system of drilling is generally used in peru, but there has been some rotary drilling in the zorritos field. drilling in argentina has been 97 largely done by the galician pole tool system, which is a modifica- tion of the canadian system, the equipment providing for a larger and heavier rig. ‘the american standard cable system ts also in use in argentina, and there is some rotary and also hydraulic circulating drilling. in trinidad, rotary drilling is employed almost exclusively for this purpose. the free fall system, a modification of the canadian pole tool system, is used in russia. in this there is a free fall of the tools, which are then picked up; american methods are also being adopted. in galicia, as well as in rumania, the canadian pole tool system, modified and adapted, is generally used, but the hydraulic circulating system is also in use, the standard cable system with portable rig is used almost exclusively in italy, and the same system, without portable rig, in persia, india and egypt. the galician pole tool system is used in the dutch east indies. in japan the rotary system, introduced in the akita field in 1913, is used almost ex- clusively. electric power has made advances in the united states, in texas, wyoming, california and the mid-continent fields. it has been adopted in rumania, and in the balakhani-sabunchi-romani- surakhani area and the bibi-eibat field of russia. electrification of the yenangyaung field of burma has also been undertaken. the use of compressed air to increase oil extraction has been introduced in certain producing areas. new exploration methods.—in the mid-continent field of the united states, core drilling (either by the diamond drill or ordinary rotary method) has been employed to advantage. improvements have been made in taking cores from wells. up to 1925 no satisfac- tory device had been worked out which would enable an oriented core to be obtained. the use of cores for determining the amount of dip, even without an orientation, is of value in finding oil. palaeonto- logic examination of well cuttings will open up new sources‘of cil and much is being done on correlation by microscopic examinations. during the post-war period the most notable progress in the applica- tion of new methods was made in the gulf coast area of ‘texas and louisiana, where the salt dome type structure governs oil accumu- lation. (scophysical methods have been applied with notable suc- cess, the discovery of three domes by means of the torsion balance and the seismograph is the first result of exploration by geophysical methods. great possibilities exist of recovering from depleted oil fields. in 1925 four methods of oil recovery from depleted oil fields were in use: flooding, air or gas pressure, dewatering and mining, all these methods have been successfully used, the first three in the united states and the fourth in france. the most notable achieve- ments in flooding are in the bradford (pennsylvania) field. under the auspices of the american petroleum institute a movement to standardise oil-well equipment had gained great headway by 1925 and was being closely watched in other countries. committees were working on the standardisation of specifications for steel and iron pipe, rig irons, wire rope and manila cordage, rigs and derricks, cable drilling tool joints, pumping equipment and engines, rotary drilling equipment, belting, otl-fleld boilers and steel storage, iv. transport and storage pipe lines.—with its large crude oil production obtained from fields often far from refining and consuming centres, the petroleum industry of the united states has developed pipe line systems of great mileage and capacity (see 21.320). in the fields themselves there are networks of gathering lines connecting the wells with main trunk lines and railways; the trunk line systems connect the fields with the refining centres. it was estimated in 1924 that the length of pipe lines in the united states amounted to about 65,000 miles. practically all of the crude oil produced is transported by pipe line, some of it only a few miles and some of it as far as 1,700 miles. pipe lines in mexico have been constructed from the panuco and topila fields to tampico and from the southern fields to tampico and directly from the southern fields to the gulf coast, where sca load- ing lines are installed. there is an international trunk line running into canada connecting with lines in ohio. pipe lines are part of oil development in all countries, usually connecting oil fields with refineries or with railroads or sea terminals. sea loading lines.—sea loading lines have been installed and are operating in mexico, peru, trinidad, russia, california and other places. these lines make possible the loading of vessels several miles at sea and are usually installed where no deep water harbours exist and where, because of the shallow water, the building of piers would be very expensive. the lines are submarine and are usually coupled ashore, stretched out on rails, and drawn into the water by vessels. when it is impossible to couple the pipe ashore, this is usually done on barges or rafts and the line deposited as the work proceeds. the sca loading lines off tuxpam, mexico, have been pulled up following failure of mexico's “ golden lane.” storage.—crude oil storage facilities, steel tanks or reservoirs, are grouped together on what are generally known as tank farms. steel tanks are usually of 37,000 or 55,000 bar. capacity, placed about 500 ft. apart from centre to centre. each tank is surrounded by a levee of sufficient height to hold the entire content of the tank, and enclosed for the purpose of isolating fires. crude oil is stored in steel tanks, concrete tanks and earthern reservoirs, while many of the lease tanks are wooden. in the united states, at the end of 1924, 348,000,000 bar, of crude oi] were held in pipe line and tank farm 98 storage. tanks are installed at refineries for holding oi! during the running at the plants and for storage preparatory to shipment to markets. stocks of refined products held at united states refineries at the clgse of 1924 totalled 114,000,000 barrels. investigation and experimentation are constantly directed to the reduction of evapora- tion losses of crude oil and refined products during storage. tanks are usually protected from fire by steam lines from the boiler house so that free steam can be turned into the tanks on the approach of a thunder storm. this steam displaces the explosive mixture in the tanks. the water spray method is also used. at pipe line stations, and at tank farms and refineries where there is a large number of tanks, fire protective systems which utilise a frothy or foam mixture are often installed. tank vessels—the tank vessel plays a large part in the modern petroleum industry. it is used for transporting crude oil from pro- ducing countries and districts to refining countries and centres, and for carrying refined products in bulk to the markets of the world. on june 30 1914 world tankers numbered 366 vessels, totalling 1,441,196 tons; on june 30 1925 the world’s tankers of 500 gross tons and over numbered 1,072, with aggregate tonnage of 5,310,533 tons, of which 478 vessels, totalling 2,411,719 tons, were american and 352 vessels, of 1,936,132 tons, were british. great advances have been made in tanker construction and in loading and unloading cargoes. v. the refining of oil refinery operations.—the rapid expansion of the internal com- bustion engine, which, as developed in motor vehicles, began to be of importance as a consuming agency of petroleum products in 1907, caused gasolene (petrol) to become the chief by-product of crude oil. later, the conversion of coal-burning vessels and industrial plants to the use of oil, and the extension of utilisation of the diesel engine (an internal combustion engine which does not demand so volatile an oil as gasolene) in the marine and in the industrial fields, placed fuel oil in a position of great prominence. [ven so great an increase in crude oil production as was recorded between 1908 and 1924 could not have supplied these consuming agencies had not refining methods been improved, new processes developed, and refinery capacity greatly expanded. as in the case of crude oil production the greatest refinery expansion has been in the united states. it is estimated that in 1915 there were 302 refineries with a crude oil capacity of 1,043,245 bar. daily; on nov. 1 1924 there were 553 re- fincrics with a daily capacity of 2,934,842 barrels. united states refineries in 1924 ran 644,000,000 bar. of crude ol and produced 8,960,000,000 gal. of gasolene, 2,521,000,000 gal. of kerosene, 13,460,000,000 gal. of gas oil and fuel oil, 1,155,000,000 gal. of lubricating oil, 516,000,000 ib. of wax, 761,000 tons of coke and 2,546,000 tons of asphalt. the principal refining centres in the united states are in the mid-continent territory, in the pennsylvania region, and along the atlantic, gulf and pacific coasts. every large producing area has developed, a refining industry, while the seaboard plants, in most instances, owe their location to strategic advantages respecting large domestic and export markets. mexico has built up a substantial refining industry, although the largest pro- portion of its crude oil production is transported to the united states for topping and refining, in most part by atlantic and gulf coast plants. most of the mexican plants are topping plants (that is, they divide the crude into tops, distillates and gas and fuel oils) but there are a few more complete refineries. all the refineries are located along or adjacent to the gulf of mexico or the eastern seaboard, comparatively near the producing fields. canada has developed a substantial refining industry, these re- fineries operating on canadian, united states, mexican and peru- vian crude oil. there are one or more refincries or topping plants in venezuela, the island of curacao, colombia, trinidad, peru and argentina, these operating on domestic oil or oil imported from near- by territories. galician crude oil is handied by refineries located within a radius of about 150 m. from the city of lemberg, in and near the oilfields, and also by the continental refineries in ilungary, austria and germany. it is estimated that galician refineries are capable of handling about 40% of the crude production. rumania’s refineries are mainty located in the prahova district and also in the bacau, dambovita, constantsa and neam* districts. russian re- fineries are located at blacktown, a suburb of baku, and at grozani, bolshaya, rakushka, ekaterinodar and shirvansky. there are local refineries at suez in egypt, and in persia, india, the east indies and japan; persian oil is also being handled by a refinery at swansea, great britain. refining methods.—the processes employed in the separation of the various constituents of crude petroleum into marketable products are many and varied, and while often apparently complex in nature, can be ultimately resolved into one or more of the basic methods listed below, or else fall under the head of alited operations, such as blending, compounding, grease-making, distilling, etc. these latter are not strictly refining processes in a purely technical sense, but are all incidental to the general operation of a refinery. basic refining methods are: fractional distillation, chemical treatment, cold press- ing, fractional fusion, cold settling, decolourisation and cracking. fractional distillation, distilling or, ‘‘ stilling ” as it is often termed, may be defined as the separation by volatilisation of one group of petroleum constituents from another, in some form.of closed appara- petroleum tus, by the aid of directly or indirectly applied heat. except in the case of a few unimportant crudes, it is universally practised and is the most important art in the wnole scope of refining. distilling methods may be classified undcr distillation by dry heat; (a) topping, skimming and stripping, (4) coking, (¢) rerunning, (d) sweetening, (e) cracking; and distillation by steam; (a) steam stilling, (6) reduc- ing, (c) cracking. the adoption of continuous process stills was one of the most im- portant advances, occurring about i910. they were first introduced by norman henderson, a british chemist in connection with the distillation of shale oil. vhis system was subsequently universally adopted. topping and skimming plants to raise the flash point and to dehydrate heavy oil multiplied rapidly, particularly in the united states. numerous special refining processes have been introduced, and it is practicable to give only a partial list representative of types: the simplex refining (trumbull) process, originally intended as a continuous topping system, has been so improved that it is now a highly efficient method for the fractionation of almost any type of crude; the sharples process of centrifuging is another; the edeleanu process brings out the possibilities of the separation of petroleum products by selective solvent action; a purely chemical process is that of carleton ellis, american chemist, for the production of petrohol (isopropyl alcohol); more recently dr. a. d. little, american chemist, announced the development of secondary alcohol recovery processes. in 1926 the petroleum industry was in the midst of intensive devel- opment of distillation methods, the most important phase of the business. evidences of this are the bubble tower, thermal efficiency and high vacuum. twenty years before, the early recognition of the value of heat exchange resulted in the use of a shallow tank or box in the ground filled with water and containing submerged pipes through which the ingoing cold oil and the rundown hot oil were cir- culated separately. from this exceedingly indirect beginning has come the highly developed heat exchanger with its compact arrange- ment and high-speed efficiency. various types of drums and pots on the overhead lines from stills, particularly for the redistillation of light products, were the forerunners of the bubble towers and dephlegmating columns which serve their purpose in a more com- plete separation of desired products in a single or limited number of operations. scientific development along the line of chemical treatment has resulted in several new methods, such as the hydrochlorite process for the conditioning of light distillates, the process for the use of liquid sulphur dioxide, and various phases of the use of anhydrous aluminium chloride. several extraction methods for reducing emul- sions and obtaining more or less valuable by-products have also been proposed. sulphuric acid and soda still remain the chief reagents for treating processes. development of continuous counter- flow methods, which have been of particular advantage in the handling of light products, is an engineering contribution to the ad- vancement of the art of treating petroleum products. the old cum- bersome method of removal of wax from petroleum products has been superseded by modern pressing equipment. the refiner now has at his disposal almost any range desired of artificially low tem- pe crue? one of the most convincing developments along this line 1as been that of the centrifugal method for the removal of wax in the production of bright stock, which has been utilised by the engineer in the conservation of crude oil supply; thousands of barrels of cut oil are now being conditioned to pipe line grade by this com- paratively simple means. as regards filtration or decolorisation, fuller’s earth is the chief agency used for decolorising and purifying mincral oils; its use has been developed mainly along the line of re- covery processes which serve to put the clay into a condition for re-use more or less approximating the fresh materia]. some special furnaces have been developed for this purpose. more attention has recently been given to the use of finer grades of earth, which has resulted in the development of the so-called contact process. the application of this process consists primarily of the mixing or con- tacting of the fine adsorbent at much higher oil temperature then had been used for percolation. claims are made for further gains in colour yield, as well as quality, when the oil to be contacted has received a light preliminary acid treatment with or without neu- tralisation. at the same time, considerable attention is being given to the improvement of adsorptive matcrials themselves, with the result that there are a number of high-powered clays on the market which give excellent results when properly applied. cracking processes —the growing importance of the internal combustion engine made necessary a higher yield of motor fuel from the limited crude oil supply, if the demands of this consuming agency were to be met. the progress that was made after 1913 in the cracking art represents the greatest scientific achievement of the oil industry between i910 and 1925. cracking has made possible the supplying of a sufficient quantity of gasolene to meet the tremen- dously increased demands of the motor car, as evidenced by the estimate that in 1924 cracked gasolene amounted to over 20% of the total gasolene manufactured at american refineries. the baste feature of all gasolene cracking is the subjecting of a hydrocarbon (such as gas oil) to superatmospheric pressures and high temperatures, which accomplish the breaking up or cracking of the molecules of the stock under treatment. the residue from one treatment by a crack- petrology ing process may be again and again subjected to the same process until substantially the entire mass is converted into gasolene. the percentage of gasolene which it is possible to extract from a given uantity of crude oil depends largely upon the quality of the oil. ‘racked gasolene in general appearance is indistinguishable from first run or straight run gasolene and is not kept separate in handling or shipping. cracking processes may be classified into two groups: (1) processes in which the oil in vapour form is thermally or energetically treated (2) processes in which the heat or other form of energy is applied to the oil in liquid form, with some part of the liquid in contact with the vapour. the use of pressure or of catalysts may be a part of processes of either class (see 21.322). actual commercial develop- ment dates from the patents of dr. w. m. burton, american chem- ist, in 1913. dr. burton’s processes, controlled by the standard oil co. (indiana), were widely installed throughout the industry under licensing arrangements from 1917 to ig21. more recently the use of other processes have greatly increased. probably the best known of modern successful cracking systems are the burton, including the modifications of humphreys, clark and others; ellis tube-and-tank; cross; dubbs; holmes-manley; and jenkins; but there are many others employed by individual companies which are not so widely known because they have never been offered for licensing to other companies. natural gas——the united states and canada produce all but a small fraction of the natural gas output of the world (see 21.321). the main areas of pennsylvania, west virginia and ohio have developed remarkable staying qualities, and these three states pro- duced some two-thirds of the total production of the continent. the mid-continent field has shown a great increase in the natural gas production, and the wyoming field has proved productive. there is some natural gas production in russia, rumania, persia, galicia, india, japan and mexico. the total production of natural gas in the united states in 1924 was 1,016,000,000,000,000 cu. feet. it is estimated that no less than 14,000,000 inhabitants of the united states use this fuel as a source of heat, light and power. natural gasolene.—natural gasolene, sometimes termed natural gas gasolene, or casing-head gasolene, has grown into a large industry and scientifically has made great strides. although the foundation of the natural gas gasolene industry in the united states was laid in 1903-4, the real expansion of this important phase of gasolene pro- duction began in 1909. in 1911, the first year for which the statistics on the subject are available, 132 plants produced 7,425,839 gal. of raw gasolene from natural gas. in 1924 the industry included 1,096 plants, which produced 933,861,000 gal. of raw gasolene. of the total, 639 were compression plants producing 257,894,000 gal., 445 were absorption plants producing 670,678,000 gal., and 12 were charcoal plants producing 4,064,000 gallons. in 1925 the methods of extracting gasolene from natural gas depended upon the prin- ciples of compression, cooling and absorption. the use of gasolene stabilising processes for minimising losses occasioned by evaporation and weathering of natural gasolene, has far-reaching influences upon the properties of products as obtained from the various extraction processes. marketing of products;—expansion of the use of petroleum prod- ucts has resulted in many improvements in marketing methods and great additions to marketing equipment and facilities. in the united states a large number of tank cars 1s used in transporting products from refineries to consuming centres and to ports for ship- ment. the tank car is still used to some extent to carry crude oil from the field to refineries, chietly when a new field is opened up and before pipe line connections have been made. tank cars are widely used in europe for petroleum products. there were 49,901 petroleum tank cars in the united states and canada on jan. 1 1914, and by 1924 the number had increased to 125,862, rigid requirements are enforced in tank car construction in the united states. cars must be of steam boiler quality, and exceptional strength is prescribed for the frame. the insulated tank car to handle highly volatile casing- head gasolene has been successfully introduced, and is also being adopted for transporting straight-run gasolene because it reduces loss by evaporation. the growth of motor vehicle gasolene demand, particularly extensive and rapid in the united states, has created new distributing methods and devices. fuel-oil bunkering stations have been established along the ocean routes to meet the increase in the oil-burning naval and merchant flects of all countries. these stations include large storage tanks, and in some cases, berth and loading facilities, but in many instances they are simply storage reservoirs and oil is loaded on steamers from barges supplied from these stations. it is estimated that the num- ber of fuel-oil stations for steamships located on trading routes approaches 300. bibliography.—r. f. bacon and w. a. hamor, the american petroleum industry (1916); r. h. johnson and l. g. huntley, ov and gas production (1916); f. g. clapp, review of present know!- edge regarding the petroleum resources of south america (1917); a. b. thompson, oi field developmeni and petroleum mining (1917); r. arnold, mantal for the orl and gas industry (1918); c. p. bowe, ot! storage tanks and reservoirs (1918); i. cross, andbook of petroleum, asphalt and natural gas, 2nd ed. (1919); a. lidgett, petroleum (1919); j. m. wadsworth, removal of the lighter [lydro- 99 carbons from petroleum by continuous distillation (1919); v. c. alderson, oi! shale industry (1920); c. p. bowie, extinguishing and preventing ou and gas fires (1920); v. ross, evolution of the ou industry (1920); world atlas of commercial geology (washington, 1921); d. t. day, handbook of the petrolenm industry (1922); j. h. wiggins, evaporation loss of petroleum in the mid-continent field (1922); e. h. leslie, afotor fuels, their production and technology (1923); transactions of the american institute of mining and metal- lurgic engineers (1924). also r. arnold, conservation of the oil and gas resources of the americas; h. barringer, ou! storage, transport and distribution; r. h. brownlee, development of cracking equipment; f. julius fohs, technologie progress in the oil industry; c. m. hunter, peire- leum in argentina; h. f. mason, reports of u.s. bureau of mines; v. f. marsters, geology of the peruvian fields; e. de golyer, state- menis on mexico; j. f. oakleaf, the application of science to petro- leum refining: l. c. sands, ot! development and production; a. d. smith, refiaing: i. c. white, the rapid exhaustion of ohio's natural gas resources, (l. m. f.)