Ranch Field Research Articles

Dillinger Ranch Field, Campbell County, Wyoming: ABSTRACT

Located in east-central Campbell County on the eastern flank of the Powder River basin, Wyoming, the Dillinger Ranch field produces oil from the B Sand section of the Permian part of the Minnelusa Formation. The field is defined by 17 wells and 5 dry holes. Total field reserves are estimated to be 5-10 million barrels of oil. The trap is formed by the intersection of a structural nose with an updip truncation of reservoir sandstone in a shale-filled channel. Post-Minnelusa streams cut deeply into the formation and removed substantial portions of the alternating sandstone, carbonate, and anhydrite sequence. The Opeche Shale was then deposited over the entire basin flank, filling in the drainage valleys. Much later, the Laramide orogeny tilted the eastern flank of the basin toward the southwest. Migrating hydrocarbons were unable to move updip at those places where the reservoir sandstones encountered the impermeable shale seal in the channels. It is anticipated that many more fields will be discovered in the Minnelusa in similar stratigraphic traps along the eastern flank of the Powder River basin. End_of_Article - Last_Page 1573------------

Practical Application of Interference Tests

Abstract This paper describes field application and calculation of an interference test in the North Anderson Ranch (Wolfcamp) field, Lea County, N. M. With the proper application of core and fluid analysis information in connection with bottom-hole pressure measurements, the drainage area of producing wells and the spacing requirement for an entire field can be calculated. Published formulas are used in the calculation. A modified 160 acre five-spot pattern was used in the field test whereby the center well as the observation well was surrounded by four producing wells. Bottom-hole pressures were measured continuously in all five wells during the first part of the test. The information was evaluated after the pre-determined amount of oil was produced. The test then was continued for the remainder of the month. Excellent agreement between calculated and measured drawdown was obtained, verifying the unsteady-state flow equations which have been developed and which are published in the literature. Introduction This paper describes the field application and calculation of an interference test in a reservoir in a Wolfcamp field in Lea County, N. M. It was the purpose of the test to determine the drainage area and spacing requirements for this reservoir. Well completion information indicated that each well location had experienced drainage prior to being drilled. When each well was completed it had a lower initial bottom-hole pressure than the preceding well, indicating some drainage, Furthermore, material balance calculations gave apparent drainage areas far in excess of the field-wide spacing rule of 40 acres/well. The test was undertaken to substantiate this behavior in order to avoid the drilling of unnecessary wells and to obtain 80-acre allowables for the field. Primary Development and Production History The North Anderson Ranch (Wolfcamp) field was discovered in May, 1958, with the completion of the well, Gulf Oil Corp. State 1-A. However, at that time it was not recognized as a new field. It was believed to be an extension to the Anderson Ranch Wolfcamp field, which was discovered in July, 1953. During 1958, two more wells were completed in the reservoir. Then in 1960, Union Oil Co. successfully completed its State No. 1–33 in the center of the 360-acre exploratory unit. This touched off an active development program and by the end of 1961 there were 11 wells producing from the Wolfcamp in the Subject area. During the same time interval, the production rate more than tripled from approximately 450 BOPD during 1959 to over 1,500 BOPD, corresponding to the 40-acre allowables for the wells (see Fig. 2). All wells were completed as flowing producers. By now, the field is producing at a rate of 2,375 BOPD from 16 wells and has a cumulative production of 1.8 million bbl. Six of the wells producing from the Wolfcamp in the North Anderson Ranch area are completed in more than one zone, although they are all in the Wolfcamp. The zones cannot be correlated with 100 per cent certainty and only the five wells incorporated in the subject test are definitely producing from the same Source of supply. This has been called the C Zone. The other wells are producing from the A and B zones. No communication has been found between the zones. JPT P. 249^

Some Aspects of Oil Exploration in California

Today, many of the industry9s critical problems result from an oversupply of relatively cheap oil because, on a worldwide basis, recent exploration has been too successful. California has had a glorious role in this petroleum exploration for a period of nearly 100 years. During most of this time it has ranked as the first or second oil-producing state. Furthermore, it has been a substantial foreign exporter of crude oil and products. The state9s production history is characterized by substantial annual increases up through 1953, and an annual decline since that year. The annual discovered reserves during this same period, however, show great fluctuations; since 1940 the annual discovered reserves have been relatively small and much below annual production. The principal oil-producing areas of California are the San Joaquin, Los Angeles, Ventura, Santa Maria, and Cuyama-Salinas basins. To the end of 1961, the 295 oil fields in the state have produced about 12.3 billion barrels of crude. The changing exploration methods are illustrated by the discovery of 6 selected oil fields. The Midway-Sunset field was discovered in 1901 by drilling near oil seeps. The Ventura Avenue oil field discovery in 1916 marked the early application of surface geology and the anticlinal theory. The Santa Fe Springs field in 1919 is important as the first discovery attributed to the geomorphologic concept of domal structure being reflected in alluviated surface topography. The 1936 Wilmington field discovery was the result of the early use of the seismic reflection method. This field is also famous as the world9s largest water-flooding operation. The Russell Ranch field discovered in 1948 exemplifies the combination of surface and subsurface geology. The Wheeler Ridge oil field discovered in 1922 in shallow Miocene sands was rediscovered in 1952 in Eocene sands below a subsurface thrust fault, an example of success by subsurface geology and deeper drilling. Present oil exploration is high in state offshore areas partly because of new techniques for drilling and completing wells in water. All petroleum geologists are challenged to find petroleum reserves at competitive costs, to contribute to the science of geology and its applications, to advance the professional competence of geologists, and to contribute to the economic prosperity of our states and our nation.

Brooks Ranch Oil Field, Natrona and Converse Counties, Wyoming: ABSTRACT

The Brooks Ranch field is a stratigraphic-type oil field in T. 33 N., R. 77 W., Natrona and Converse counties, Wyoming. Field production is from the Upper Cretaceous Second Frontier sandstone. The sandstone thins eastward to a wedge-edge from a gross thickness of 25 feet at the western margin of the field. The oil accumulation is controlled by an anticlinal axis which intersects the stratigraphic thinning. The productive area of the field will exceed 3,000 acres. The average permeability of 5 millidarcys is low, whereas the porosity ranges between 18 and 20 per cent. Initial production varies considerably from well to well, averaging about 100 barrels of oil per day per well. The discovery well drilled by Dan C. Morton in March, 1957, is located in the SE., SE., SE., Sec. 9. The field now has 50 producing wells. End_of_Article - Last_Page 1095------------

GEOPHYSICAL CASE HISTORY OF THE ANDERSON RANCH FIELD, LEA COUNTY, NEW MEXICO

The Northwest Shelf area of Southwest New Mexico has had an exceptionally rapid growth as an oil producing province. The Anderson Ranch field, discovered by the Continental Oil Company in 1953, is one of the typically prolific oil fields in this Northwest Shelf area. This field (Figure 1) is the most southwesterly of a series of Devonian oil fields in the Northwest Shelf area of New Mexico. It is located 22 miles west of Lovington, New Mexico in sections 2 and 11, T. 16 S.‐R. 32 E., Lea County, New Mexico. The Anderson Ranch area was first found to be anomalous by a shallow oil well drilled in 1927 which found the Rustler Anhydrite unusually high. Core drilling carried out in 1940 developed an Anhydrite nose over the area. A reflection seismograph survey was carried out in the period from 1950 to 1951 which succeeded in mapping a closed anticline in the face of many difficulties in obtaining usable seismograms. It is believed that the seismic map prepared for the deepest horizon was caused by multiple reflections. The anticline so revealed was drilled in a unitized drilling program and a well was completed in the Devonian for an initial potential of 1,968 barrels of oil per day. This was the discovery well.

Developments in West Texas and Southeastern New Mexico in 1953

Exploratory drilling increased during the past year, with a total number of 1,125 tests in 1953 as compared with 1,039 in 1952. The per cent successful increased slightly, being 27 per cent in 1953 and 26 per cent in 1952. Of the new-field wildcat discoveries, 51 were located by seismograph and 54 by subsurface methods. Of the 301 successful exploratory wells, 129 were Permian, 107 Pennsylvanian, and 65 pre-Pennsylvanian. The most important new discoveries were the Prichard, Wemac, Andrews, and Emma-Ellenburger fields in Andrews County, the Headlee field in Ector County, the Lea field in Crane County, Texas, and the Anderson Ranch field in Lea County, New Mexico. Development drilling decreased sharply because of the shut-in of a large part of the Spraberry field to arrest excessive gas flaring. Total development wells in 1953 were 3,401 as compared with 4,640 in 1952. Seismic activity was down slightly with 5,382 crew-weeks in 1953 as compared with 5,843 in 1952. Gravity-meter exploration was up with 677 crew-weeks in 1953 and 455 crew-weeks in 1952. Keen competition and high prices, plus over-rides and oil payments, figured prominently in the leasing picture on the Central Basin platform, Northwestern shelf, and Eastern shelf, and in the Midland basin. Movement into some of the less explored basins is slow, because the present producing provinces are far from being completely explored and are still highly attractive to the oil companies.

Engineering Study of the Cook Ranch Field, Shackelford County, Texas

Abstract The Cook Ranch Field produces from a very permeable lens of Cook Sand of lower Permian or upper Pennsylvanian age, occurring at an average depth of 1,300'Ft. The field was discovered in 1926, and has been operated with low pressure gas injection since July, 1927, one of the first such projects in Texas. Cumulative recovery to Dec. 31, 1950, was 14,701,131 bbl of crude oil, an average of 1,013 bbl per acre-ft of oil section, and 72.5 per cent of the oil originally in place. Analysis of the reservoir performance indicates that gravity drainage has been an important factor in the producing mechanism. The high permeability and uniformity of the reservoir were extremely favorable for this type of operation. Introduction The Cook Ranch Field is the largest of a number of relatively small, shallow producing areas near Albany, in Shackelford County, Texas. This field is one of the first to be operated by gas injection in Texas, and probably is the most successful low pressure gas injection project ever attempted. The field is owned entirely by Roeser and Pendleton, Inc., and Continental Oil Co., aud has been operated by Roeser and Pendleton, Inc., since it was discovered. This study has been made possible through the cooperation of Roeser and Pendleton, Inc., in making available a remarkably complete set of records covering all phases of their operations. The purpose of this paper is to present a summary of the history of the operations through Dec. 31, 1950, and to analyze some of the factors which appear to be responsible for the success of the project. Information concerning the physical plant and the early gas injection history has been presented in an earlier paper.

Developments in Cuyama Valley--1950: ABSTRACT

The Cuyama Valley in 1950 continues to be an important area in California for the drilling of both field development wells and wildcats. More than 50,000 barrels of high-gravity oil are now produced daily from the combined fields of Cuyama. The Russell Ranch field, discovered in June, 1948, has reached a state of almost complete development and now produces 21,000 barrels of oil per day from 138 wells. The South Cuyama field, discovered in May, 1949, is incompletely developed and now produces about 29,000 barrels of oil per day from 155 wells. The geology of these proved fields is not reviewed. Thus far in 1950, about 45 wildcat wells have been drilled in the Cuyama-Carrizo area and only the three which resulted in new discoveries in the Morales Canyon area of North Cuyama were successful. This rather low discovery ratio of 1:15 reflects the complexity of the geologic structure and the difficulty of finding new oil in Cuyama Valley. The Superior Oil Company completed Government No. 18-2 in Sec. 2, T. 11 N., R. 28 W., S.B.B. & M., on April 1, 1950, flowing from an undisclosed formation in the interval 5,635-6,125 feet, 500 barrels per day of 37.5° gravity oil, 2.5% cut, through ½-inch bean with 400 pounds pressure and 250 M.c.f. gas. Immediately surrounding this well, one additional pumper has been completed, three dry holes abandoned, and one well is currentl drilling. End_Page 2380------------------------------ On April 25, 1950, the Hancock-Mohawk-Oceanic No. 65-10 well on the Clayton lease in Sec. 10, T. 11 N., R. 28 W., was completed as a new-pool discovery pumping 75 barrels per day of 32.8° gravity oil, 1% cut, from the Morales formation (Pliocene). There are now eleven wells in a proved area of about 120 acres, producing a total of about 800 barrels per day. The limits of the field at the south and east have been established. On August 22, 1950, the Hancock Oil Company made a discovery about 2 3/4 miles northwest of the Superior well in the Hancock-Bishop No. 44-31 well in Sec. 31, T. 32 S., R. 20 E., M.D.B. & M. The well was completed, pumping 226 barrels per day of 36.6° gravity oil, 0.4% cut, 100 pounds casing pressure and 100 M.c.f. gas from a new lower Miocene sand i the interval 5,785-6,020 feet. Three wells are drilling in the area. End_of_Article - Last_Page 2381------------

Developments in South Texas in 1948

The development in South Texas during 1948 showed a 23 per cent increase over the previous year. In all 2,987 tests, 2,158 wells in proved areas and 829 wildcat wells, were drilled and resulted in 1,915 successful completions. The exploratory development resulted in the discovery of 81 producing reservoirs in 79 new areas, 3 of the discovery wells being dual completions. The most important of the new discoveries are the Doering Ranch field in Frio County, the Holly field in DeWitt County, the South Long Horn field in Duval County, the San Pablo field in Jim Hogg County, the Quien Sabe field in Webb County, the East Long Mott field in Calhoun County, and the Sarita field in Kenedy County. Wells drilled in productive areas uncovered 155 new producing beds in 84 fields, the rio-Vicksburg trend accounting for 108 of the total. At the close of 1948 oil wells totaling 16,738 had produced 169,739,954 barrels of oil, 10 per cent more than had been produced from the area during the previous year. Thirty-six per cent of the oil wells in the South Texas district are now being serviced for casinghead gas.

Developments in California in 1948

Total exploratory footage in 488 exploratory wells completed as producers or abandoned as dry holes in 1948 was 2,005,366 feet. Comparable figures for 1947: 352 wells and 1,571,257 feet. Exploratory activity during 1948 was greater by 38.6 per cent as to number of wells and 27.6 per cent as to footage than in 1947. Exploratory wells were 16.6 per cent and 15.6 per cent successful as to number and footage, respectively. They discovered a total of 49 new fields and new pools, of which 9 were gas and 40 were oil. The most promising of the oil discoveries were the Russell Ranch field in Cuyama Valley, the Guijarral Hills field in the Coalinga area, and the Campbell pool in the San Ardo field in the Salinas Valley. Several oil fields were extended substantially. None of the ne gas fields and pools can be rated as a major discovery. New fields, new pools, and extensions added 151,000,000 barrels to oil reserves, 8,000,000 barrels to natural-gas liquids reserves, and 240,000,000 MCF to gas reserves. Production during the year was about 340,069,000 barrels of crude oil, 189,933,000 MCF of gas from dry gas fields, 421,200,000 MCF of wet gas from oil fields, and 26,480,000 barrels of natural gas liquids (including condensate). Basement was reached by 57 unsuccessful exploratory wells at depths varying from about 205 to 10,300 feet. There were 64 exploratory wells active at the end of 1948.

Geology of Russell Ranch and South Cuyama Oil Fields, Cuyama Valley, California: ABSTRACT

Since the discovery of high-gravity oil in the Cuyama Valley on June 13, 1948, development and exploration have proceeded at a rapid pace. As of October 15, 1949, these operations had resulted in the discovery of two oil fields, and completion of 151 producers, with a restricted daily production of 29,200 barrels. Thirteen development wells and six wildcats were currently drilling. The two oil fields lie in the western part of the valley. Development to date in the Russell Ranch field covers an area approximately 4½ miles long and ½ mile wide. Trending southeasterly from the top of White Rock Bluff, it straddles the Cuyama River, lying partly in San Luis Obispo County and partly in Santa Barbara County. Production here is from two sand zones, Dibblee, the upper, and Colgrove, the lower. Both are of lower Miocene age. The oil field occurs on a northeast-dipping monocline End_Page 2058------------------------------ against a large, normal fault, known as the Russell fault. This fault trends approximately N. 30° W., and dips steeply to the southwest. The Dibblee sand lies at depths ranging generally from 2,800 to 3,200 feet. The Colgrove zone lies approximately 1,000 feet below the top of the Dibblee. The South Cuyama field, discovered in May of this year, lies in the foothills at the south margin of the valley, about 4 miles southeast of the Russell Ranch field in Santa Barbara County. Its productive limits have not yet been determined, but present development and productive outposts extend over an area 3 miles long and more than 1½ miles wide. This oil field occurs on an elongated faulted dome, its long axis trending northwest and southeast. Production is from the Dibblee zone, encountered at depths ranging from 4,000 to 4,400 feet. Exploration has not yet been carried below this zone. Unlike the Russell Ranch field, South Cuyama has a gas cap area at the crest of the dome. The Dibblee sand is a friable, well sorted arkose, ranging from fine- to coarse-grained. It is characterized by high porosity, high permeability, and high productive indices. Potentials in both fields range upward to several thousand barrels per day. The Colgrove sand is similar in character to the Dibblee and well potentials are comparable, though generally somewhat smaller due to the lesser thickness of sand. Both fields are being developed on a ten-acre spacing pattern, with duplicate wells where the Colgrove zone is productive. End_of_Article - Last_Page 2059------------

Russell Ranch Oil Field, Cuyama Valley: ABSTRACT

The Cuyama Valley, lying in the Coast Ranges midway between the San Joaquin and Santa Maria districts, was established as a commercial oil producing province by the completion of Richfield Oil Corporation's Russell No. 28-5, on June 13, 1948. This new field is known as the Russell Ranch oil field. It is situated in the western portion of the valley and is producing from Lower Miocene sands on fault closures. Previously less than a dozen holes and one small producer from upper Miocene sand (Norris Oil Company's Cuyama No. 2) had been drilled in the valley. Geologically the Cuyama Valley, between the Caliente and San Rafael uplifts, comprises granitic basement and Cretaceous to Pliocene strata folded and faulted in east-southeast trends. Eocene strata are present only in the eastern part of the valley, the Oligocene (?) is a red bed facies, 5,000 feet of lower Miocene sands pinch out southwestward, marine Miocene shales and sands grade eastward into red beds and the Pliocene strata are entirely non-marine. Initial production of the discovery well, Richfield Oil Corporation's Russell No. 28-5, was 508 barrels per day, flowing, 38° gravity oil, from the interval 2,970-3,360 feet. This interval is lower Miocene and has been designated the Dibblee zone. Five days later another pool was established 2¼ miles northwest by completion of Richfield Oil Corporation's Anderson No. 37-30, flowing 3,041 barrels per day, 33.5° gravity oil, from the interval 2,800-3,019 feet, also lower Miocene. The former, named the Russell area, had on October 1, 1948, eight completed wells with initial rates to 2,500 barrels per day, and maximum sand interval of 350 feet. The latter, designated Whiterock area, had nine completed wells with initial rates to 4,000 barrels per day, and maximum sand inter al of 480 feet. Also, on October 1, 1948, the Russell Ranch field has eight active development wells, while eight wildcats were drilling at locations as far as 9 miles from production. End_of_Article - Last_Page 2319------------

PRECISE MEASUREMENT OF DEEP ELECTRICAL ANOMALIES

A method of electrical prospecting has been developed in which the deleterious effects of superficial inhomogeneities in resistivity are eliminated. An electrode configuration is used consisting of a current electrode at “infinity,” a pair of current electrodes with a constant separation of a few hundred feet which are used alternately, and a pair of potential electrodes with a constant separation of a few hundred feet, collinear with the pair of current electrodes, and at a distance from them which is varied to secure depth resolution. It is demonstrated that superficial influences are eliminated by forming the resistivity increment, the ratio between apparent resistivity determined by use of the closer current electrode of the alternate pair and that determined by use of the farther current electrode of the alternate pair. It is also demonstrated that the area explored is below a point approximately half‐way between the alternate pair of current electrodes. Resistivity increment curves, called Resistologs by the authors, can be correlated from station to station, and after they are correlated the lateral variation in the electrical properties of selected subsurface zones can be studied. As a result of the latter characteristic of the measurements, a possibility exists for the direct location of oil and gas, observational evidence for which is presented. The results of surveys made in Hart County, Kentucky, and in the Sam Fordyce, Seven Sisters, Pettus, Branyon, Dunlap, Oakville, and Rhode Ranch fields of Southwest Texas are displayed.

West Ranch Oil Field, Jackson County, Texas

The West Ranch field is in the southwest corner of Jackson County, Texas. The discovery well of the main part of the field was the Magnolia Petroleum Company's West Ranch No. 3-A, which was completed in August, 1938. The field has nine producing zones, most of which are Frio in age. For a major field it is exceptionally free from faulting. Like most Gulf Coast fields the structure is probably due to the movement of a deep salt mass. No drilling difficulties are encountered in the field, and wells are completed in 12 to 15 days. The field covers approximately 10,400 acres, on which 390 producing wells have been drilled. Cumulative production to October, 1942, was 10,238,794 barrels of oil and 12,790,905,000 cubic feet of gas.