1038 01I, RESOURCES OF

Oil Resources of Peru

By V. F. MARSTERS, KANSAS CITY, Mo. Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 (New York Meeting, February, 1922) PERU has produced petroleum since the early seventies, the first work being in the Zorritos field, in the Province of Tumbes, adjoining . In the early nineties, the Negritos field, in the Department of , <'allle into prominence, and by 1905 had attained an annual production of 335,160 bbl. The early development of the field was under the general direction of the London & Paeific Petroleum Co., but it is now handled by the International Petroleum Co. In 1900 and 1901, the Lobitos field became the scene of marked aetivity. In 1905, its total production amounted to 75,000 bhl.; it has continued to increase, as has Negritos. From 1897 to 1902, there was prospecting in the region of La Brieta (or Fernandez), on the Mancora River, about 25 to 30 km. from the coast. Small production of a heavy oil was obtained from three different sands. 80 far as the author knows, no work has been done in that locality since 1902. There are thus four distinct fields in the north end of the Peruvian ('oastal plain. The remaining productive locality of Peru is the Pirin or Pusi field, at the northwest end of , Department of PUI10, in southern Peru. The first prospecting near Pusi was done by Brown Brothers, of Los Angeles, Calif., who ohtained modest production about 1906 i accord­ ing to reports, activities ceased about 1914 or 1915. The maximum annual production was obtained about 1908, estimated at 76,000 barrek Peru possesses two distinct geographic provinces in which we may look for the development of a larger oil industrYi namrly, the coastal plain province, and the inter-Andean plains.

COASTAL PLAIN PROVINCE The coastal province is most prominently developed in the Province of Tumbes and the Drpartments of Piura, and Lalllbayeque.! It

1 For details concerning the geology of this part of Peru, see Bol. No. 50, Cuerpo de IngpnieroR de Minas" Informp prplimillar sohrp In Zona Pptrolifpra del Norte del Pem," pOl' V. 1". 11arst('rs. V. F. MARSTERS 1039 continues north into Ecuador, and southward nearly to the north boun­ dary of the Department of Li bertad. I ts maximum width is attained be­ tween Cerro del Yllesca on the coast and Morropon on the interior edge of the plain. A short distance south of River Cana, the foot-hills of the reach the coast. The south half of the north sector occupies a broad embayment with a few outliers of the Andes dotting the shore line, while the north half represents the inner rim of the coastal plain extending into Ecuador. Farther southeast the foot-hills of the Andes reach the coast. Wherever the main transverse valleys are well developed, their lower ends Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 are V-shaped embayments partly filled by tertiary sediments. A partly marine-filled embayment of this type is found on the Jequetepeque River, which may be designated as the Pacasmayo embayment. Below this are the Chicama and Moche valleys, likewise partly filled by marine sediments, which may be designated as the Chicama and Trujillo embayments. Similar conditions occur, but on a much smaller scale, at , Casma, and HUal'llley. From Haucho to the south side of the Rimac embayment is a group of little valleys connected by a narrow coastal rim. stands near the inner apex of the Rimac delta. Marine sediments occur in the Lima embayment; similar, but smaller, embay­ ments are also found between the Rimac and the Chincha Rivers. From Chincha to Atiquipa is the central sector of Peruvian coastal plain. 2 Along the shoreward edge, as well as in sub-central locations, there are pre-Tertiary formations projecting through Tertiary sands and clays. At Paracas there are well-defined Carboniferous strata, but the interior hills are made up of Cretaceous and older rocks. The part of this sector of special interest is that between the lower part of the lea River on the northwest and Nasca and Porthachuela on the southeast. The south sector of the Peruvian coastal plain extendt:! from southeast into , beyond the Sarna River. The outstanding geo­ graphic feature of the south sector is that the present coast is occupied mostly by a small coastal pre-Tertiary ridge. Between it and the foot­ hills of the Andes is a plain varying in width from 20 to 60 kilometers.

Stratigraphy oj Coastal Plain

The south sector shows considerable variation in stratigraphy. The south part, along the border of Chile, is made up largely of Tertiary

2 For details on central and south sector of the coastal plain see BoI. No. 59, "Dos Informes sobre Ho, Moguegrea e lea," and No. 70, "lnforme sobre la Costa Sur del Peru," por. V. F. Marsters. 1040 OIL RESOURCES OF PICRU

sands and clays. Thc central and north part, however, shows a mass of lava flows interbedded with sands and clays; this feature is particularly well shown in sections from Vitor to Mollendo. They also continue to the north. Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021

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[~~~ ProdUO,r;o ,~:(;>,~j~~ @-Oil Indlc'::,flonc f2Q CoasA-t/ Plow; o 20 40 60 50 IO':} f" I --...I::::: ~ __--'-..'J--,O I I __ I _ i I 8\ - --_. --~o --It- 15 11 15 - -ts 14

FIG. I.-PRODUCING OIL FIELDS AND OTHER KNOWN PROSPECTS OF PERU.

The plains on the south end of this sector lie from 100 to 500 ft. (30-152 m.) above sea level, while the north end of the south sector, on its nner edge, rises more than 1000 ft. (305 m.) above sea level. In the central sector, extending from Chineha on the north to A(i- v. F. MARSTERS 1041

quipa on the south, LIte formations entering into the body of the coastal plain are entirely sedimentary and composed of sands, clays, and local conglomerates, which attain their greatest thickness between the lower part of the lca River and the Grande River, and Pampa de Tunga on the south. Asphaltic sands are known to exist on the lower part of the lca River, and likewise limestones in the Nasca-Portachuela were found to possess a strong petroleum odor upon fresh fracture. The limestones are doubtfully Cretaceous. Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021

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.PUSIOIL FIELD

FIG. 2.-LAKE TITICACA REGION SHOWING LOCATION OF PUBI OIL FIELD.

Although the north half of the central sector is thought generally to possess a comparatively thin series of Tertiary strata, it is not improbable that a large body of sediments may be found in the region of Pampa de Chunchanga. The Pampa de Pisco is covered with a thin coat of Tertiary sediments. Two of the many embayments existing between Chincha and the south end of the north sector of the coastal plain that deserve reference are the Trujuillo-Chicama and the Pacasmayo embayments. The greater part of the Moche River area (Trujillo) is covered by VOL. LXVm.-66 1042 OIL RESOURCES OF PEnu fiuviatile, post-Tertiary deposits; only on the outer edge may Tertiary clays be seen. The Trujillo area is connected by a narrow strip of coastal plain with the much larger Chicama embayment. This area also is almost completely covered by fluviatile post-Tertiary deposits, but Tertiary clays and sands are exposed at a few places on the shore line. Doubtless a considerable body of Tertiary sediments exists on the shore line of this embayment. One deep well has been drilled on the area for water, in which the occurrence of asphaltic sands was reported. The Pacasmayo embayment is covered mainly by recent alluvium; Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 in only a few places along the shore may Tertiary sediments be seen. The large number of pre-Tertiary outliers suggest that no great thickness of Tertiary sediments may be expected, except near the shore of the Pampa de Charcapr. North Coastal Sector3 The Pacasmayo embayment connects northward, by a very narrow strip of coastal plain, with the north sector, which is the only important oil-producing part of the coastal plain. This area begins to widen in the region of the Sana River and reaches its greatest width between Cerro dpj Yllesca and Morropon or Chulacanas. The lies on the north side of the main embayment. Facing the Cerros de Amotape the inner rim of a half-drowned coastal plain passes into Ecuador. The north sector has the greatest development of Tertiary strata known in Peru. The upper member of the Tertiary is recognized on the plains behind the town of Pyta (or ) and consists of clays, sands, and lenses of conglomerate. These reappear in the table lands northeast of Lobitos, and likewise are recognized in the plains southwest of the valley of the Tumbes. The middle member of the Tertiary, composed largely of clays and sands, is exposed on all the sea cliffs from Paita to Zorritos. From an investigation of well logs, it is apparent that also a lower member of the Tertiary exists. The deepest well drilled thus far has reached a depth of 3900 ft. (1189 m.) and is still in formations re­ garded as Tertiary.

OIL FIELDS OF NORTH COASTAL PLAIN Zorritos Field This is the most northern producing area. Drilling has been carried on along the coast for a distance of 10 km. and 3 km. inland; about 90 per cent. of the drilling is confined to the seacoast. In the northeast, exploration for oil was conducted by a French company in Quebrada Heath, but no commercial results were obtained, although oil sands were reported to have been encountered. Favorable structural conditions may be easily detected in parts of the

3 See Bo\. No. 50, ibid., p. 2. V. F. MARSTERS 1043

ZOl'l'itos field; but some of the prospecting done in this region seems not to have been guided by geological and structural conditions. The most recent developments are not fully known to the writer. At the end of 1915, 313 wells had been drilled in this field and 116 had been productive. There are three main producing sands, varying in depth from 194 to 1640 ft. (59-500 m.). The deepest well, drilled in 1915, reac ed 3020 ft. (920 m.). During 1918, the Zorritos field is reported to have produced 76,190 bbl.; its maximum output, 107,000 bbl., was reached in 1910. Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021

Lobitos Oil Field The greater part of the present productive area is located near the coast, but production is obtained also farther inland. Favorable struc­ tural conditions can be detected easily in the developed area and in many other parts of the concession, as ascertained by the writer when making investigations of this region for the Peruvian Government. The early prospecting was done evidently without reference to geological conditions, and hence failed. In 1917 the Lobitos field had about 143 producing wells. Four pro­ ducing sands are known, at depths between 400 and 2500 ft. (122-762 m.). The deepest well reached a depth of 3435 ft. (1047 m.). The total pro­ duction of 1918 was estimated at 639,098 barrels.

N egritos Oil Field The Negritos field is located southwest of Lobitos and 10 to 12 km. south of , the nearest shipping port. It occupies the largest single concession granted by the Peruvian Government, and also is the largest producing field in the Republic. The first oil wells were located close to the shore line, as at Zorritos. Exploration soon extended northeast toward Talara and likewise into the interior. This general region has several favorable structures. At the beginning of 1918, the Negritos area had brought in a total of 695 producing wells, including those of the Lagunitas area, a block of ground developed by a subsidiary company. Not less than seven oil sands are known, ranging in depth from 300 to 3000 ft. (91-914 m.). The deepest well was 3900 ft. (1189 m.), and was probably still in Tertiary sediments.

A nalysis of Oils from Fields Previously Mentioned.

p.,a CENT. Gasoline ...... 15 to 25 Kerosene ...... 20 to 24 Lubricating oils .. · ...... 20to30 Asphaltic base. Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021

Tablazo NoI O.La Cruz Lobifo.s "., ...... '" ,..... __~~#-~~- .. "."·'l ·:- ... h •. -.".,,·, .. :·;·.,·;······ B BnClo,!l-soffshalC? ;SSandslon

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FlO. 3.--8ECTIONB OF PERUVIAN OIL FIELDS. No. I, LOBITOS TO TABLAZO; No. II, PAYTA TO MORROPON; No. III, MOLLENDO TO VI TOR•

• k • UP V. F. MARSTERS 1045

Pirin or Pusi Field This field, formerly productive on a small scale, is located in the Department of , southern Peru. It may be reached by railway from Mollendo to JuIiaca, the junction of the railway from the coast with the Puno-Cuzco line. The oil field is about 25 or 30 km. northeast of . According to published statistics, the field became productive about 1906, but activities ceased about 1915. Following the northwest extension of the broken plains at the north end of Lake Titicaca, I found a series of Tertiary sediments resting upon Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 formations probably of Cretaceous age. On the southwest side of the plain, in the Lake Titicaca lowland, both Tertiary and Cretaceous forma­ tions are folded and in some places faulted. The production of the Pusi field was obtained apparently in Tertiary sediments and down the longer slope of asymmetrical anticlines. Faulting is not prominent where production has been obtained. I have not investigated the entire area covered by Tertiary sediments, but enough is known about this general region to lead me to believe that Perin is not the only locality where we may expect to find production of at least modest proportions. About 10 wells had been drilled when I visited this locality; the producing sands were found between 242 and 750 ft. (74-229 m.). After the Lake Titicaca Oil Co. ceased operations, their holdings were acquired by the "Sociedad de Petroleos Espana," which drilled about 2 wells and cleaned out the old ones. Of the 10 wells drilled by the Lake Titicaca Oil Co., five were productive. The first 10 wells were drilled from 193 to 815 ft (59-248 m.); the production was obtained between 242 and 750 ft. (74-229 m.). The 12 wells drilled by the Sociedad de Petroleos Espana ranged in depth from 170 to 240 ft. (52-128 m.) and obtained a little production from 193 to 249 ft. (59-76 m.). The sand ranged from 4 to 13 ft. (1.2-3.9 m.) in thickness. 4 The petroleum of the Pusi field is reported to have the following com­ position: PEB CIIN'T. Gasoline...... 0 to 7 Kerosene...... 7 to 20 Lubricating oils, main part of the product. Paraffine base.

GEOGRAPHICAL DISTRmUTION OF OIL SEEPAGES In the south part of Peru, seepages are known to occur in many direc­ tions from the Pirin or Pusi field. In the , they have been recognized near Huancane, to the east of Pirin; to the north­ westin the region of Yaraviri; and to the west near Lampa and Maravillas. Much of the area between these points, as well as far to the northwest, 'See tabulation of wells in "EI Petroleo en EI Peru," por R. A. DueBtua (1921). 1046 OIL RESOURCES OF PERU is occupied by Tertiary and Cretaceous formations. No detailed geologi­ cal information has been published concerning this section of the inter­ Andean plain, but personal investigations indicate that these formations extend across a part of the into the Department of Apurimac. This area seems worthy of investigation. Seepages are known also to the southwest, near Desaglladel'o, and on the border between Peru and . Similar occurrences are reported to exist to the southwest and within the limits of the high plains of Bolivia.

Seepages occur in the Department of Apurimac, as well as in the Depart­Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 ment of Cuzco, near Pillpata in the Province of Canas. 5 In the high plains near the eastern edge of the western range, seepages have been recognized in the southwest corner of the Department of . In the Department of Junin, there are a number of localities where oil-saturated formations and seepages have been found. These center around Jauja, Yauli, and Tarma. Apparently, they are associated with Cretaceous formations. The structure is so complicated, that commercial production is not to be expected. There are rather large seepages farther northwest, on the west edge of the high plains, in the southwest corner of the Department or'Huanuco. Details of the geology are not available. On the coastal plains of Peru there is some evidence of seepages at points remote from production. In the central sector, or the part extend­ ing from Chincha on the northwest to Atiquipa on the southeast, in the lower lea valley, there is considerable evidence of asphaltic sands, exposed not far from the coast. In the region of Nasca and Portachuelo there are oil-bearing limestones, probably Cretaceous. The structure is complicated and the region is not regarded as promising for oil. There is, however, a section of the coastal plain between Cerro Yungi and the ocean, occupied by Tertiary formations, where it is believed a large body of these sediments may be found. The same is true for the lower part of the Ica River region. No seepages are known on the south sector of the coastal plain. The north half of the south sector is made up of mud flows interbedded with sands and clay, and is believed to offer favorable suggestions for a test. The south half, adjacent to Chile, is composed, so far as known, entirely of sedimentary formations, largely sand and clay, and increases in width in passing into Chile, and very probably increases in thickness. The south half of the sector merits serious consideration. Seepages of fair size are known, also, near Chimbote, but it is believPll that the area covered by the coastal plain formations is too small to warrant serious consideration.

6 For additional information, see "Industria del Petroleo en El Peru durante 1915, II por R. A. Duestua (Secunda congreso cientifico Pan Americano de Washington) . v. F. MARSTERS 1047

Seepages on the East Slope of the Andes6 There have long been reports of oil seepages on the east slope of the Andes, somewhere in the vicinity of Yarimaguas, or according to the official map of Peru, near the border of the Department of San Martin with the , or on the Haullaga River. From the available information the belt of lowland' adjacent to the foothills seems to be composed of some Tertiary and probably of a much larger group of Cretaceous sediments, which should be well worth investigating. In the Y urimaguas region Duestua reports also the following oil Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 seepages: (1) Quebrada de Chipeza and Chipauta, District of Chasuta, Province of San Martin, Department of San Martin; (2) Quebrada de Potoyne, probably a tributary of Rio Santiago, Province of Bongara, Department of Amazones; (3) Quebrada de Camaya, tributary to the Rio Maranon, District of Pecca, Province of Bongara, Department of Amazones; (4) Numerous places in the district of Barranca, Depart­ ment of Loreta; (5) Quebrada de Ahuaya, tributary to Quebrada de Cashiboya running to the River Ucayali, District of Contamana, Province of U cayali.

POSSIDLE, PROBABLE, AND FAVORABLE OIIrBEARlNG TERRITORY OF PERU

ACRES 1. Area of the coastal plain of Peru considered as developed and in part proved, approximately ...... 30,875 2. Total promising area outside of the proved areas of the coastal plain, all of this being in the "north sector" ...... 500,125 3. Total possible producing area of the coastalplain ...... 1,620,610 4. Total probable producing area of the coastal plain ...... 940,305 5. Total possible producing area of the Pirin region, Lake Titicaca, Department of Puno ...... 98,800 (The above figures do not take into consideration the territory out­ side of the general lowland at the northwest end of the Titicaca Lake. It should be stated that Tertiary and Cretaceous formations occupy an enormous area to the northwest and west of the Juliaca-Yaravari­ Hauncane district.) 6. Total coastal plain area, approximately...... 3,091,915 Total interior area, Pirin region approximately...... 98,800 Total area ...... 3,190,715

OIL SHALES Apparently little attention has been paid to the possibilities of shale formations of Peru as a source of petroleum.

6 Information on this subject may be found in a pUblication by R. A. Duestua, "Estado actual y Porvenir de 180 Industria Petrolifera en El Peru," Lima (1912). See also "EI Petroleo en Peru," same author; Ministerio de Relaciones Exteriores (1921). 1048 OIL RESOURCES OF PERU While investigating coal deposits in Peru, I learned something of the distribution of shales associated with them. It is my opinion that the shale deposits known to exist on the west slope of the Andes in the Department of Libertad and may contain oil-bearing members. I am informed that one section of the west range in the likewise displays a very considerable thickness of carbonaceous shale. Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 40

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FIG. 4.-PETROLEUM PRODUCTION OF PERU FROM 1897 TO 1922. In the Department of Junin, there are large bodies of shale in thevicin­ ity of the coal mines operated by the Cerro de Pasco Mining Co. In the Cuzco region there are very large bodies of shale, but in neither of the last two regions did I find any locality where it would seem that they might possibly be oil bearing. It is believcd that the belt in the Department of Libertad may contain oil shale. The large shale deposits of Cerro de Amotape, , are too thoroughly metamorphosed to be of any importance.

FUTURE PRODUCTION OF PERU An analysis of the rate of increase in the annual production of the Republic, considered in terms of new territory recognized as either prob­ able or favorable ground for future development, should render some v. F. MARSTERS 1049

:tssistance in forlllulating :t fairly rlependahle opinion on possible future produetion.

Production oj Petroleum in Peru, 1896-1922, in Barrels

YEAR LOBIToe NEORITOS ZORRITOS PIRIN' IjA011NIT08 TOTAL 1896 47,536 1897 70,831 1898 70,905 1899 89,165 1900 274,800 Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 1901 274,800 1902 286,725 1903 278,092 1904 290,123 1905 75,000 335,160 37,720 447,880 1906 162,000 330,510 42,419 1,365 536,249 1907 279,000 396,750 65,476 15,000 756,226 1908 319,898 543,750 71,429 76,103 1,011,180 1909 421,195 740,070 70,750 76,103 1,316,118 1910 400,083 773,025 107,000 50,000 1,330,105 1911 391,290 882,698 94,048 30,000 1,398,036 1912 587,048 1,071,000 87,095 15,000 1,760,143 1913 557,355 1,136,490 83,343 10,000 346,073 2,133,261 1914 504,743 1,032,210 88,136 10,000 282,713 1,917,802 1915 664,972 1,355,925 72,736 1,000 392,618 2,487,251 1916 654,060 1,822,733 73,852 ! 2,550,645 1917 686,595 1,771,560 75,262 2,533,417 1918 639,098 1,820,814 76,190 2,536,102 1919 2,616,000 3 1920 1,993,33P 2,790,0004 1921 3,568,0006

1 Estimated. 2 Included in Negritos. 3 Quoted from Richardson, U. S. G. S. 4 Am. Petro lnst., 6Petroleum Digest, Jan. 25, 1922; Tulsa World, Jan. 21, 1921; Wall St. Journal, Jan., 1922. Inspection of the production table brings out the following conclusions. 1. The Zorritos field showed its maximum production in 1910 with 107,000 bbl., falling by 1915 to 72,736 bbl. By 1918 production had increased to 76,000 bbl., which so far as I know has not been exceeded during the last three years. The production of the field seems to be declining, or at least to have passed its maximum. 2. The figures on the Pirin field would lead the casual observer to suspect that the area is practically condemned. On the other hand, detailed investigation will show that it can be made to produce, but geographical conditions render operation difficult. 3. As a rule, the annual production of the other fields has shown a marked increase. The greatest total annual increase of production 1050 OIL RESOURCES OF PERU appears in 1920 and 1921. The peak of annual production of these fields has not yet been reached. Calculations indicate on the north sector of the coastal plain about 500,125 acres (202,550 ha.) regarded as promising ground. The area of about 30,875 acres (12,484 ha.) developed and proved is approximately but one-sixteenth of the total acreage which unmistakeably is worth testing, and some of which the author believes will prove to be commer­ cially productive. This statement does not include the probable produc­ ing acreage, which the author estimates may be 940,305 acrCRDownloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 (380,823 ha.).

OIL PRODUCTION OF PERU WITH E;';TIMATFJS ON POSSIBLE RESERVES

BARRELS Total production from 1896 to 1921, , , , , , , , , , , ' . , ' , , ...... 30,176,355 Total production for 1920, ' . , . , .... , , . 2,790,000 Total production for 1921, ' , , . , ...... 3,568,000 Increase of total production for 1921, , ...... , . 778,000 Assuming an increasingly active drilling campaign, not only on the known extensions of producing structures, but also on other coastal areas where probably favorable conditions are believed to exist, it is estimated that not less than six years will be required to prove the areal extent of productive territory throughout the entire coast. Adopting the above increment of production, placed at 770,000 bbL per annum, Peru should be producing approximately 9,180,000 bbl. annually by 1928. This is regarded as the peak of production for the Peruvian coast. The total production of the Peruvian coast from 1921 to 1928 will approximate 33,818,415 bbl.; hence the total production of the coast from 1896 to 1928 would be, .. ' , , . , , , ., ".", ... "", .. " 63,994,770 Mter proving up the areal extent of producing territory of the coast it is estimated that the peak of total annual production can be held near the maximum for a period of from five to seven years. Hence from 1928 to 1934 we would expect to obtain approximately, , , ' . , ...... " 54,000,000 Or a total production from the coast alone by 1934 of. . ' ...... , 117,994,770 As to the rate of decrease of production, after the peak has been passed, very little published data seems to be available, but such as we have on the question of permanent settled production points to the con­ clusion that we may expect the passage from the peak to settled produc­ tion to occupy about two years. On this basis the annual production of the coast by 1936 would be not less than 4,000,000 bbl. Hence, at the close of 1916, the total production of the Peruvian coastal district will be approximately .... ' .. ' , ...... , ...... 128,769,777 The period of settled production is estimated to cover not less than ten years. This period is estimated to make a total showing of 30,000,000 bbl. The total production of the Peruvian coast is therefore estimated at ...... , ...... ,. 158,769,770 For the Pirin area (Lake Titicaca region) the small amount of explora­ tion carried on has resulted in the total production of 284,571 bbl. between 1906 and 1915. It is believed that this region possesses favor­ able structures and if developed with caution and economy will add not less than 30,000,000 bbl. to the total production of the Republic. This makes a grand total of ...... , 188,769,770 v. F. MARSTERS 1051 The author believes that a vigorous drilling campaign on the coastal plain alone could bring the total annual production of Peru up to about 9,000,000 bbl. The production of Peru seems to be far below its possible maximum. In the last five years drilling has been confined to practically proven ground. The fact that the Peruvian Government has removed a portion of the coastal plain from denouncement and has placed it on the reserved list is, in part, responsible for the lack of increased activity in new localities, the development of which wouid be advantageous to Peru. Using the available published statistics on production, the preceding Downloaded from http://onepetro.org/TRANS/article-pdf/68/01/1038/2177254/spe-923038-g.pdf by guest on 01 October 2021 summary seems reasonably fair. After making some calculations on the acreage basis, and knowing that from four to seven san:ds exist in certain fields, the author feels forced to admit that the above figures must be too low. Applying the few facts at hand to the acreage regarded as probable to favorable territory, the author is confronted with the unsuspected and surprising conclusion that he must increase the final production from 3.5 to 5 times the total given above, or from 660,694,195 to 943,- 848,850 barrels. Attention is also called to the fact that the above estimates do not include the eastern interior belt, or the east slope of the Andes proper in the north part of Peru. Although no detailed work has been published on this great interior belt, significant observations are known that force us to foresee great possibilities for this region, which may be designated as the southwest corner and border of the Department of Loreto and portions of the Departments of San Martin and Amazones.