Small Amount Of Oil Research Articles

Meeteetse Field, Bighorn Basin, Wyoming: ABSTRACT

Lower Cretaceous Muddy and Upper Cretaceous Frontier sandstone reservoirs remain popular objectives for new energy reserves in the Bighorn basin of northwestern Wyoming. Predominantly structural reserves approximate 1 million bbl of oil and 20 bcf of gas from six Muddy fields, and 210 million bbl of oil and 100 bcf of gas from 16 Frontier fields. Newly established structural-stratigraphic gas production from these reservoirs is at Meeteetse field (T48-49N, R99W) on the west flank of the basin where Muddy Frontier bar sandstones trend across a long, narrow, horst-associated anticline. Terra Resources 1-33 Federal (Sec. 33, T49N, R99W) established the shallower pool discovery in 1979. Ten wells are now drilled along or near the axis of the structure. Production history is only now beginning because wells were shut in during field development due to absence of a gas line. The Frontier is productive in the middle two of its four units. Most initial production rates are between 1 and 2 MMCFGD; small amounts of oil, condensate, and water have been produced from some wells. The Muddy is a discrete sandstone unit with thin shale interbeds. Most initial production rates are between 1 and 3 MMCFGD; small amounts of oil, condensate, and water are also produced. Some production is from commingled Frontier zones and from commingled Frontier and Muddy. End_of_Article - Last_Page 955------------

Enhanced oil recovery: Environmental issues and state regulatory programs

During 1977–1978, Oak Ridge National Laboratory (ORNL) prepared environmental impact assessments for nine U.S. Department of Energy-sponsored enhanced oil recovery (EOR) field demonstration projects located in six states and reviewed the oil regulations for all oil-producing states. These evaluations revealed some potentially important environmental impacts associated with EOR including (1) pollution of land and surface waters from spills or leaks of oil and brine or other chemicals, (2) loss of biota, (3) excessive erosion and sedimentation (mostly in hilly terrain) and subsequent deterioration of surface-water quality, (4) contamination of groundwater, and (5) excessive air emissions from thermal operations. Potential groundwater impacts include (1) production of toxic and carcinogenic substances from synergistic interactions among chemicals used primarily in the micellar-polymer flooding technique, (2) formation of acid waters with small amounts of oil and metal residues and oxides from in situ combustion, and (3) corrosion of well casings and potential leaks of hydrogen sulfide primarily from injection of miscible carbon dioxide. For use of EOR techniques to expand in an environmentally acceptable manner, environmental planning (including monitoring, protection measures, and reclamation strategies) must be an integral part of the initial project development. Acceptable monitoring, prevention, mitigation, and reclamation procedures are available for most of the identified environmental problems, but the best techniques may not be known by operators or required by law. Most states have stringent controls for plugging abandoned wells and disposal of waste material, but these may not be enforced because of limited staff and funds. However, other environmental considerations, e.g., reclamation plans, water quality and other monitoring programs, and abandonment plans, are often lacking. The need for additional environmental planning and monitoring requirements specific to the oil-production industry is emphasized. States are encouraged to continue strengthening and upgrading their oil-regulatory programs to safeguard the environment. More studies are needed on (1) toxicity and carcinogenicity of chemicals used in injection processes, (2) evaluation of groundwater monitoring methods, and (3) reclamation procedures for soils contaminated by oil and brine.

EXPLORATION PROSPECTS AND FUTURE PETROLEUM POTENTIAL OF THE CANADIAN ARCTIC ISLANDS

The offshore and onshore area of the Canadian Arctic Archipelago, 1.7 million sq km, is one of the most prospective frontier regions in Canada. The first onshore well was drilled at Winter Harbour in 1961, and the first offshore well was drilled from an ice‐strengthened island at Hecla in 1974. To date, more than 140 wells have been drilled, and 12.0 Tcf of recoverable gas have been discovered as well as a small amount of oil. The gas is largely Lower Jurassic, with smaller amounts in Triassic and Lower Cretaceous strata.The Canadian Arctic Archipelago is actually underlain by two prospective basins: the older Franklinian geosyncline, or basin, Cambrian through Devonian; and the younger Sverdrup successor basin, Late Mississippian through Middle Eocene. The principal orogenic events to affect the area were the Caledonian uplift (Devonian), the Ellesmerian orogeny, a compressive fold system was produced with décollement of the southern part of the Franklinian on the Ordovician Bay Fiord salt. Vertical uplift, with compression in the east, dominated the Eurekan orogeny.Objectives in the Franklinian basin include sub‐Bay Fiord (sub‐Ordovician) structures—mainly Lower Paleozoic carbonates and some terrigenous clastics; supra‐salt folds of the Parry Islands fold belt—Ordovician‐Devonian reefs and porous shelf carbonates; other Lower Paleozoic reef bodies; and porous Devonian clastics in the Parry Islands fold belt. Sverdrup basin objectives include mainly terrigenous clastic reservoirs in Pennsylvanian‐Cretaceous rocks, with structural (salt anticlines and diapirs; some folds in the east) and stratigraphic (pinchouts on the flanks of structures, and along the folds) possibilities. The greatest potential in the Sverdrup basin is in the central and western parts. Ultimate recovery of gas is estimated to be at least 125 Tcf.

The effect of a crude oil spill on cereals

A break in an oil pipeline in mid-winter caused oil to travel underground over a distance of about 850 m. Oil moved upwards through cracks in the frozen soil, especially during recovery attempts. The contamination in the affected area varied considerably both horizontally and vertically. Oil contamination and damage to the soil structure due to the clean-up efforts caused serious yield decreases during the next summer. In subsequent growing seasons oil was the major factor in reducing yields. Total above-ground dry matter and grain yield were affected similarly by oil pollution; even very small amounts of oil (less than 0·2% by weight) in the 0–30 cm or 0–90 cm depth reduced yields considerably. Oil reduced the available N content of the soil and markedly reduced water uptake by wheat from contaminated layers or from below such layers. Problems in reclaiming soils with oil contamination below the topsoil are discussed.

Petroleum Developments in North Africa in 1979

In the 6 countries covered by this report, the extent of valid petroleum rights, seismic work, and drilling was nearly the same as in 1978. The success rate of wildcat drilling decreased slightly, to 28% (33% in 1978), with 26 oil or gas discoveries. In southwestern Tunisia, the Amoco Sabrina Nord 1 tested 930 bbl of 39° API oil from Cambrian-Ordovician sandstones--the first oil to come from lower Paleozoic rocks in Tunisia. First commercial oil from Cambrian-Ordovician rocks in western Libya was discovered by Agip A1-NC40 which flowed 1,400 b/d. Highlight of the year in North Africa was in the Interior basin of Sudan where the Chevron Abu Gabra 1 tested 900 BOPD of 40° API oil from Cretaceous rocks; 2 other wells, spudded in late 1979 in the same area, have tested 3,200 and 7,300 b/d, respectively, in early 1980. Discovery well of the Interior basin was Chevron Unity 1 which tested small amounts of oil in 1978. Oil production in North Africa in 1979 averaged 3,939,500 b/d compared with 3,802,800 b/d in 1978, an increase of 3.6%.

The role of kerogen constituents in oil generation in the Gevar'am Formation (Lower Cretaceous), Israel

Kerogen from various samples of the Gevar'am Formation (Early Cretaceous, Israel) were analyzed for their elemental composition, and by I.R. and ESR spectroscopy. The results were compared with other organochemical characteristics of the basin (Amit, 1978, Bull. Am. Assoc. Pet. Geol., V. 62 p. 827–836). The types of organic material and their role in the formation of oil were investigated. It appears that the kerogen is mostly constituted of terrestrially derived organic matter. A small amount of marine-derived organic matter is also inferred. The kerogen of terrestrial origin is a poor oil producer and is expected to generate oil only at a higher stage of maturation than the Gevar'am Formation has attained. Any hydrocarbons that have been generated in this formation were probably generated from that part of the kerogen thought to be marine derived. Thus the Gevar'am Formation is considered as a potential source rock which has generated only a small amount of oil.

Petroleum Production from Basal Greenbrier Formation in Hyden West Pool, Eastern Kentucky: ABSTRACT

The Hyden West pool of northeastern Leslie County in eastern Kentucky produces from the Mississippian Big Lime (Greenbrier or Newman Limestone). The pool includes approximately 7,000 acres (2,800 ha.), with more than 60 wells which range in depth from 1,900 to 2,400 ft (570 to 720 m). Production in the pool is primarily gas, with small amounts of oil, from the basal Greenbrier. Drill cuttings from 10 wells within the pool and on its margins were studied using a binocular microscope. The thickness of the Greenbrier was determined throughout the pool from gamma-ray logs and samples. Drillers' logs have been used cautiously, and only if other sources of data were unavailable. These thicknesses, as well as intervals within the Greenbrier and structural data from the logs, were used to construct maps and cross sections of the pool. The Greenbrier has a thickness of between 160 and 250 ft (48 and 75 m) in this pool, and consists of limestone and dolomite, with minor amounts of shale. Evidence suggests that the sequence was deposited in a shallow epicontinental sea that was transgressing across low-lying, exposed surfaces of the Maccrady siltstone. The dolomite present in the basal part of the Greenbrier is mainly a secondary replacement of limestone. Porosity and permeability in the dolomite provide the pay zone of the Hyden West pool. End_of_Article - Last_Page 844------------

WHEN LUBRICATION FAILS

In most ball bearings, grease functions primarily as a storehouse for the small amount of oil needed to coat ball, raceway and separator surfaces. Bearing life tests indicate that as a grease ages in service, it finally dries to a degree where it fails to provide this lubrication demand when about half the original oil is gone. This condition of dryness which leads to failure is also related to operating factors such as bearing temperature, speed and load.

Solvent Flooding Displacement Efficiency in Relation to Ternary Phase Behavior

Abstract The chief objective of the study was to exercise control on the system phase behavior through the use of mixtures of two alcohols exhibiting opposite phase behavior characteristics in the alcohol-hydrocarbon-water system involved. Such systems were employed in displacements in porous media to ascertain their effectiveness. Introduction Displacement of oil and water in a porous medium by a mutually miscible alcohol or other solvent has been the subject of numerous investigations. This process, in spite of its limited scope as an oil recovery method, has certain mechanistic features that are of value in gaining an understanding of some of the newer recovery techniques (e.g., the Maraflood* process). The works of Gatlin and Slobod, proposing piston-like displacement of oil and water by a miscible alcohol; of Taber et al., describing the displacement mechanism in terms of the ternary phase behavior involved; and of Holm and Csaszar, defining displacement mechanism in terms of phase velocity ratio, are major contributions in this area. In a later work, Taber and Meyer suggested the addition of small amounts of oil and water (as the case may be) to the alcohol used for displacement, since this helped to obtain piston-like displacements with systems that are usually characterized by the efficient displacement of either oil or water. Apparatus, Experimental Procedure, and Simulator Procedure, and Simulator The procedure employed for determining the equilibrium phase behavior of ternary systems involved the titration of a hydrocarbon-water (or brine) mixture by the particular solvent (pure alcohol, or alcohol mixture) for the determination of the binodal curve, and the analysis by refractive index measurement of ternary mixtures having known compositions for the determination of the tie lines. Since the procedure is valid for strictly ternary systems, its use in this case where essentially quaternary systems are involved would yield the total alcohol content rather than the correct proportion of each alcohol. The ternary diagrams presented should be viewed with this limitation in mind. presented should be viewed with this limitation in mind. The apparatus used for experimental runs in porous media consisted of a positive displacement Ruska pump and a core encased in a steel pipe. Suitable sampling apparatus and auxiliary equipment were employed. Most runs consisted of injecting a slug of the particular solvent into a core initially containing a residual oil (waterflood) or irreducible water saturation, at a constant rate, and then following the slug by water or brine. The effluent samples collected were analyzed for the hydrocarbon, water and alcohol in order to plot the production histories. Complete experimental details and fluid production histories. Complete experimental details and fluid properties are given in Ref. 6. Table 1 lists the properties are given in Ref. 6. Table 1 lists the properties of the porous media used. Computer simulations of some of the experimental runs, as well as exploratory simulations, were carried out using the method earlier reported. The method basically consists in the representation of a porous medium by a certain number of cells containing immobile oil (or oleic) and water (or aqueous) fractions into which alcohol is injected in a stepwise manner allowing for phase changes.

A Reservoir Study of the Friendswood Field

To temporarily stop migration of oil into the original gas cap, the existing gas injection project in this Texas Gulf Coast field was expanded. For the purpose, water turned out to be a more efficient displacing medium than gas. By unitizing the field and then injecting 80,000 barrels of water a day, oil migration can be stopped and 55 million more barrels of oil will be recovered. Introduction The Friendswood field (sometimes referred to as Webster) was discovered by Humble in 1937. It is located on the upper Texas Gulf Coast immediately south of Houston (Fig. 1), and has productive sands originally encompassing more than 4,100 acres. Approximately 215 wells were required to fully develop the field to 20-acre spacing. The sands are very prolific and the average well exhibits a productivity index of approximately 29 B/D per psi productivity index of approximately 29 B/D per psi drawdown. Cumulative Frio sand oil production has been 310 million bbl, and reservoir pressure has dropped only 340 psi since discovery. Principal production has been from upper Frio sands of Miocene age. Although prorated together, these sands have been divided into 17 members for reservoir control purposes. A small amount of oil (2 million bbl) has been produced from the Marginulina sands, which lie just above the Frio. The field contains several fault systems, and, because of fault juxtaposition, communication occurs between some of the sand members. Several studies, resulting in MER hearings, workover programs, and a gas injection program, have been conducted in the past. For the study discussed here, those past programs were reviewed and additional necessary programs were determined. Current fluid contacts for each sand member were ascertained on the basis of conventional neutron logs, pulsed neutron logs, induction electric logs, and well production histories. Oil and gas volumes were then production histories. Oil and gas volumes were then mapped for original and current conditions. Material balance and unsteady-state water influx calculations were used to match past reservoir behavior and to predict future performance. predict future performance. JPT P. 685

Stratigraphy of Cretaceous Fox Hills Sandstone, East Flank of Rock Springs Uplift, Sweetwater County, Wyoming: ABSTRACT

The Upper Cretaceous Fox Hills Sandstone on the east flank of the Rock Springs uplift is a regressive sequence of sandstone and siltstone which was deposited in shallow neritic and estuarine environments. It End_Page 538------------------------------ overlies, and intertongues with the marine Lewis Shale, and is overlain by, and intertongues with the nonmarine Lance Formation. Exposed Fox Hills strata consist of littoral and shallow neritic, very fine-grained sandstone and siltstone which commonly are overlain, with marked disconformity, by fine- to medium-grained sandstone deposited in estuarine environments. The origin of these widespread erosion surfaces is believed to be related to the lateral migration of estuary and tidal channels behind prograding barrier-island shorelines. In the subsurface east of the outcrop, the stratigraphic position of the Fox Hills rises, in an east to southeast direction, over 400 ft in a distance of 15 mi. Subsurface shoreline trends in this area are north to northeast, and appear to form a large embayment across the present Wamsutter arch. North and east of this area, in the vicinity of the North Desert Springs field, the typical Fox Hills Sandstone and uppermost Lewis Shale pass laterally into a thick sequence of siltstone and shale interpreted by Asquith to be a major delta. Small amounts of oil and gas have been produced from the Fox Hills, and numerous shows have been reported from wells on the east flank of the Rock Springs uplift. The optimum targets for future exploration appear to be porous Fox Hills shoreline and estuarine sandstones, where they interfinger in an up-dip direction with shales of the Lance Formation. End_of_Article - Last_Page 539------------

Factors influencing protection against experimental tuberculosis in mice by heat-stable cell wall vaccines.

Ribi, E. (Rocky Mountain Laboratory, Hamilton, Mont.), R. L. Anacker, W. Brehmer, G. Goode, C. L. Larson, R. H. List, K. C. Milner, and W. C. Wicht. Factors influencing protection against experimental tuberculosis in mice by heat-stable cell wall vaccines. J. Bacteriol. 92:869-879. 1966.-Studies of nonviable, heat-stable vaccines for active protection against experimental tuberculosis have been continued with a test involving aerosol challenge of intravenously vaccinated mice. The previously reported activating effect of light mineral oil on disrupted cells of the BCG strain was found to be shared by certain other mineral oils and a synthetic, 24-carbon hydrocarbon, but not by kerosene or any of several vegetable oils. Dry cell walls coated with a small amount of oil and dispersed in saline with aid of an emulsifier were suitable for intravenous administration and were effective in promoting resistance to challenge. Oil used in this manner, in contrast to water-in-oil emulsions of the Freund type which could not be administered intravenously, did not potentiate the tuberculin-sensitizing activity of the cell walls. Although the amount of oil required for full effect was small (< 0.5 ml/100 mg of dry antigen), there was a critical level below which optimal enhancement was not achieved. More stable suspensions than could be obtained with the other oils were readily prepared from cell walls treated with the synthetic hydrocarbon, 7-n-hexyloctadecane. Extended experience has shown that in this test system both the viable BCG standard vaccine and heated, oil-treated experimental vaccines gave highly reproducible results showing graded responses to graded doses.

Effective nonliving vaccine against experimental tuberculosis in mice.

Ribi, Edgar (Rocky Mountain Laboratory, Hamilton, Mont.), Carl Larson, William Wicht, Robert List, and Granville Goode. Effective nonliving vaccine against experimental tuberculosis in mice. J. Bacteriol. 91:975-983. 1966.-Antituberculosis vaccines were prepared in one of three manners: lyophilized BCG suspended in light mineral oil was disrupted in a Sorvall pressure cell and the "oil disruption product" was collected by centrifugation; BCG was disrupted in water, lyophilized, and worked into a paste with a small amount of oil (about 0.16 ml per 50 mg); BCG was disrupted in water, and the cell wall fraction was isolated, lyophilized, and prepared in an oil paste. These vaccines were suspended in Tween-saline to a concentration of 5 mg/ml and heated at 65 C for 30 min. In protection tests based on pulmonary infection with Mycobacterium tuberculosis H37Rv, the median number of virulent organisms in lung tissue of mice immunized with a few hundred micrograms of these three vaccines was 3 to 4 logs lower than in unvaccinated control mice. A similar dose of viable BCG standard vaccine reduced the lung count 1 to 2 logs below the controls. Protection afforded by nonviable, whole BCG, with or without oil, was of only borderline significance. Since oil-treated fractions containing cell walls produced effective immunity, while the oil-treated protoplasm or whole cells were not active, the protective antigen appeared to be an inner component of the cell wall, exposed when the cell was disrupted, and activated by oil. Extraction of oil from immunogenic disruption products resulted in loss of ability of the products to confer protection against the aerosol challenge, whereas high protection against the conventional challenge by intravenous infection with up to 1.4 x 10(8) cells of M. tuberculosis H37Rv was retained. Retreatment with oil of these nonimmunogenic products restored the immunogenicity if the oil was applied to dried products. The consistent finding that moisture interferes with the enhancement of the vaccine potency by oil suggested that such enhancement may not be the same as that ordinarily produced by water-in-oil emulsions.

The Fluid Travel Log

Walker, Terry,* Welex, A Div. of Halliburton Co., Houston, Tex., Sherwood, John,* Welex, A Div. of Halliburton Co., Oklahoma City, Okla., Sumner, Cyril R.,* Welex, A Div. of Halliburton Co., Houston, Tex., Marshall, Ray, Welex, A Div. of Halliburton Co., Houston, Tex. *Members AIME Abstract By using down-hole ejection of radioactive fluid and two gamma counters the velocity of flow at a given point or the determination of whether or not fluid has passed a given point can be determined accurately on production or injection wells. In this method the counters are positioned at the proper points, a small concentrated quantity of radioactive fluid is ejected, and a recorder operating in time-drive records the time interval or fluid movement past the counters, each counter recording on a separate pen for a permanent record. Inside the casing or in open hole if a caliper log is available, a time profile and resulting velocity profile determines the full injection or production distribution. During injection profiling the procedures readily point out and locate any channeling which may exist. Equally simple job procedures are available for detecting casing leaks, tubing leaks, leaking packers and many other operational problems which are detectable by a study of fluid flow. Field examples are given to indicate the success and utility of the method. Of great importance to the operations engineer is the fact that job procedures with the well at normal operating conditions are standardized for ready field interpretation. Introduction With the increasing application of water flooding, pressure maintenance and other recovery-increasing techniques in the oil industry, an accurate means of determining input profiles is an absolute requirement. The injection fluid costs, especially in miscible floods and gas injection, are such that channeling behind the pipe must be located and remedied. Also, the efficiency of secondary recovery techniques requires orderly flood-front movement throughout the vertical extent of the zones. Therefore, the input profile must be as desired, and accurate profiling by some means is necessary on the injection wells after completion and at intervals during the flood. In some cases in waterflood projects, even input profiles are not the only requirement-the production profiles should also be such that orderly flood-front movement is obtained. Again, an accurate means of profiling is required at intervals during the project. There are a number of production problems where accurate production profiles can be of great aid in remedial work. Where wells are producing large amounts of water along with a small amount of oil from either long perforated intervals or open hole, shutting off the water section and allowing greater drawdown on the oil section can greatly increase oil production. In wells of this type, of course, are the condition where the highest permeability zones are watered out with oil remaining in the less permeable zones. JPT P. 851ˆ

Developments in Atlantic Coastal States Between New Jersey and South Carolina in 1960

Geophysical exploration has been reported from the Continental Shelf off New Jersey, North Carolina, and South Carolina. One test well was drilled on the Coastal Plain of Virginia and 3 in North Carolina. New wells were drilled in Buchanan, Dickenson, and Wise counties, in western Virginia. Production of gas was reported from western Maryland and western Virginia with a small amount of oil from the Rose Hill field in Lee County, Virginia.

Geology and Oil in Ventura Basin East of San Gabriel Fault: ABSTRACT

The discovery in August, 1957, of a small commercial oil field in the Ventura Basin east of the San Gabriel-Palomas Canyon fault trend has led the industry to increased interest and a flurry of exploratory activity in this area. The sedimentary rocks of the region, also a topographic basin, are bounded on the north, east, and south by mountainous masses of pre-Tertiary igneous and metamorphic rocks. On the west the area is delineated by the San Gabriel-Palomas Canyon fault trend beyond which, to the west, lies the main part of the Ventura Basin. The oldest rocks of the sedimentary sequence are Paleocene marine clastics exposed against the northern basement mass. Unconformably overlying the Paleocene strata is the fluviatile Oligocene Vasquez formation. Above the Vasquez with unconformable relation the Mint Canyon group of fluviatile and lacustrine origin was deposited during early to late Miocene time. A subsequent invasion of the sea from the west led to the deposition of the Modelo(?) (Castaic formation). In outcrop the Modelo(?) unconformably overlies the Mint Canyon, while along the southwest edge of the area subsurface evidence suggests interfingering with the Mint Canyon. To the north, the Modelo(?) section grades to the overlying basal part of the Ridge Basin group. Following a period of erosion, the southwest part of he area was encroached upon by Pliocene seas to deposit the Pico formation. At the edges of this Pico sea there were contemporaneously deposited the fluviatile sediments of the Saugus formation. Later in Pliocene time the sea retreated westward and the non-marine Saugus rocks blanketed the area. Prominent post-Saugus Pleistocene to recent terrace deposits are found along the main drainages and the intervening ridges. The part of the area occupied by sediments is a broad westerly plunging syncline which has several smaller folds superimposed upon its flanks. Nearly all the anticlines plunge west or northwest with areas of critical east closure rare and insignificant. Faulting is most prominent in the pre-Miocene formations and is developed in a northeast-southwest system between the San Andreas and San Gabriel major faults. The San Gabriel-Palomas Canyon fault trend involves beds as young as Pliocene and, during a part of the Miocene, it appears to have acted as a barrier or sill to deposition. Approximately 125 wildcat wells have been drilled in the 132 square miles of area covered by the Mint Canyon-Modelo(?)-Saugus outcrops. Of the above, 50 wells tested only the Mint Canyon formation; 50 wells tested primarily the Modelo(?) strata; and 25 wells were tests of the Pico-Saugus section. To date, one small field (Tapia) has established commercial production in the area. This field is a stratigraphic trap in as and of that part of the Saugus beds equivalent to the downdip Pico formation. Sub-commercial production has been obtained from the Modelo(?) in the Elizabeth Lake Canyon area and on the eastern edge of the Honor Rancho field. A small amount of oil has recently been obtained from Mint Canyon beds in the Bouquet Canyon area, and this formation has also demonstrated low-vo ume gas in several locales. End_of_Article - Last_Page 254------------

Stratigraphy of La Honda and San Gregorio Quadrangles: ABSTRACT

The oldest rocks exposed are Upper Cretaceous foraminiferal mudstones, graded sandstones, and conglomerates (9,500 feet) occurring in a fault slice along the coast south of Pescadero. Not in contact is the Butano formation (5,000 feet) of Eocene age, consisting of interbedded sandstones, siltstones, and mudstones. The sandstones are thicker and cleaner in the upper part of the Butano formation and produce oil in the La Honda field. Conformably overlying the Butano formation are 2,500 feet of San Lorenzo mudstones and siltstones (upper Eocene A-1 zone to lower Zemorrian) which are cut by diabase sills and dikes. These dikes were feeders to basalt flows which poured from subaerial volcanoes into shallow water. The volcanic rocks are interbedded with upper Zemorrian and Sauc sian mudstones, quartzose sandstones, and organic calcarenites. This sequence totals 2,000 feet in thickness and is overlain by 500 feet of brown chert and laminated mudstone (Relizian ?). Transgressing all older rocks are the upper Miocene cherts and diatomaceous mudstones (0-9,000 feet thick) of the Monterey formation. The Pliocene Purisima formation (5,650 feet) overlies the Monterey comformably and is still transgressive. It is characterized by the first influx of andesitic debris, probably from the Sierra Nevada. The Purisima is divided into five mappable members, which from the base upward are: tuffaceous siltstone and sandstone member containing small amounts of oil in the La Honda field (2,150 feet); siliceous mudstone member (2,300 feet); pebbly sandstone member (150-350 feet); udstone member (450 feet); fine sandstone member (400 feet). Pleistocene terraces, recent alluvium, and landslides complete the stratigraphic column. It is believed that the Butano, the lower Miocene volcanics and the Purisima formation can be directly correlated across the present San Andreas fault into the Stanford-Woodside area. The correlation suggests that lateral displacements along the fault in this area may be a mile or two, but not hundreds of miles. End_of_Article - Last_Page 257------------

Oil and Gas Developments in Tennessee in 1958

A total of 25 test wells were drilled in Tennessee during 1958. One well produced a small amount of oil and 2 non-commercial gas wells were discovered. Exploratory footage for the 25 tests was 20,245 ft.

A weighing method for measuring the induction period of marine and other oils

SummaryA convenient method for measuring the length of the induction period of marine and other oils and unsaturated fatty acid esters depends upon determining the increases in weight. Small amounts of oil with or without additives are held in constant temperature ovens and weighed at regular intervals. Some of the details of technique are described.

Geology and Exploration for Oil in the Huasna District, San Luis Obispo County: ABSTRACT

The Huasna district, an area of approximately 100 square miles, lies at the southern end of the Santa Lucia Range in the California Coast Range province about 12 miles northeast of the town of Santa Maria. Geologically it consists of a synclinal basin filled with Miocene sediments and interbedded volcanics. The basin is roughly limited on the east and west by two nearly parallel faults. On or near these boundaries Miocene strata are found in fault or depositional contact with Franciscan rocks on the west and Cretaceous sediments on the east. Anticlines have formed on the flanks of the major syncline. Middle and upper Miocene (Monterey) shales and sands crop out along the eastern flank of the syncline. Basinward they are overlain by 2,000 feet of Santa Margarita sands and shales. Wells drilled within the deeper portion of the basin penetrate 4,000-6,500 feet of brown cherty and siliceous shales and dark brown calcareous shales representing all the foraminiferal stages from upper Mohnian to Relizian. Shows of tarry oil occur throughout this interval both in outcrop and in wells, probably accounting for many of the shows of oil recorded by early tests in the district. At and throughout the basal portion of this predominantly shale section volcanic interbeds of tuff, agglomerate and ashy sands of middle and lower Miocene (Saucesian ?) age are encountered. Incomplete records on earlier wells and lack of deep stratigraphic penetration in more than one well near the center of the basin lead to some conjecture as to the nature and distribution of lower Miocene sediments. Thirty-five wells have been drilled in the Huasna district since 1898. Two or three wells have produced a small amount of oil. The Barneberg No. 2, drilled on the Tar Springs anticline, has produced 11,400 barrels of 16 degrees A.P.I. oil, which appears to have come from near the Santa Margarita-Monterey gradational contact and from within the underlying locally fractured shales. Recent wells drilled nearby failed to develop production. The possibilities of stratigraphic traps at depth within the basin and of better structural position on some of the asymmetric anticlines are indicated as being the objectives of future exploration in the district. End_of_Article - Last_Page 2630------------