Ton Of Shale Research Articles

Biogenic methane and carbon dioxide generation in organic-rich shales from southeastern Brazil

Brazilian shale formations are potential biogenic gas systems that are still poorly understood. Organic-rich shales from Ponta Grossa (Devonian, Paraná Basin), Irati (Permian, Paraná Basin) and Tremembé (Paleogene, Taubaté Basin) Formations were analyzed in order to evaluate their biogenic methane (CH4) generation potential and to constrain environmental and geological conditions that may affect methanogenic metabolism. Additionally, the generation potential of carbon dioxide (CO2) was evaluated in combination with CH4 to constrain Brazilian organic-rich shales as sources of greenhouse gas to the atmosphere. Twenty-four shale samples were used for batch incubations in dry and wet conditions and after headspace refilling and acetic acid addition during one year. Physico-chemical parameters such as Total Organic Carbon (TOC), specific surface area and pore volume were characterized in order to understand general geologic controls on CH4 and CO2 production. Biogenic gas generation rates in dry tests reached up to 3.17ml/t·d (milliliter per ton of shale per day) for CH4 and 2.45×103ml/t·d for CO2 during the first 30days, with wet samples producing about 54% more CH4 and 151% more CO2 than dry samples. Headspace refilling did not demonstrate significant changes on production rates, while acetic acid addition restarted or increased CH4 and CO2 production rates in several microcosms. Shales from the Irati Formation showed the highest methane production rates for both dry and wet tests, with unusual ranges of δ13CCH4 and δ13CCO2 that may be linked to hydrocarbon biodegradation. The studied shale formations have different pore volume and specific surface area, but without significant influence over biogenic methane generation.

New Insights into Devonian Oil Shale Resource of Eastern United States: ABSTRACT

The Devonian oil shales of the eastern United States constitute one of the nation's major energy resources. New process technology applicable to these shales increases the percentage End_Page 953------------------------------ of organic carbon extracted thereby doubling the yield of oil per ton. The process uses hydrogen at temperatures of 500 to 730°C and pressures of 20 to 50 atm. Experimental work in equipment capable of processing up to one ton of shale per hour has confirmed the technical and economic feasibility of above-ground hydroretorting of Devonian oil shales. Investigation of more than 550 samples from some 150 locations in 13 states indicates that IGT's HYTORTTM process can give organic carbon recoveries from 2 to 2.5 times those of conventional retorting, resulting in yields of 25 to 30 gal/ton at many localities, compared with 10 to 15 gal/ton using Fischer Assay. Resource estimates are based on above-ground hydroretorting and four criteria: overburden less than 200 ft (59 m), stripping ratio less than 2.5 to 1, shale thickness of 10 ft (3 m) or more, and organic carbon at least 10% by weight. Resource estimates include: Kentucky 190 billion bbl, Ohio 140 billion bbl, Tennessee 44 billion bbl, Indiana 40 billion bbl, Michigan 5 billion bbl, and Alabama 4 billion bbl. Seven other states have been sampled but recoverable resources were not identified. The total recoverable resource exceeds 440 billion bbl of synthetic oil if all near-surface shales of more quality were mined for above-ground hydroretorting. End_of_Article - Last_Page 954------------

Potential Contribution of Oil Shale to Energy Needs of United States and Other Parts of the World: ABSTRACT

The present worldwide dependence on imported crude oil may be partly relieved by production of oil from oil shale. More than 3 trillion bbl of oil are contained in known organic-rich shale deposits that will yield 10 or more gal of oil per ton of shale. About two-thirds of this resource is in the Green River Formation that underlies parts of northwestern Colorado, northeastern Utah, and southwestern Wyoming in the United States. Oil shale, which has been mined mainly utilizing conventional mining and surface-retorting techniques, has produced shale oil continuously during the past century. Although Scotland has the longest history of production (more than 100 years), Russia and China combined have produced about 80% of the approximately 1 billion tons of oil shale mined since 1919. The United States has yet to spawn a commercially viable oil-shale industry; however, since 1919 almost half a million bbl of shale oil have been produced, chiefly from the oil shales of the Green River Formation in Colorado. More than 350,000 bbl of this amount has been produced in large-scale pilot operations since 1964. Sufficient resources are available on the United States federal prototype oil-shale lease tracts in Colorado and Utah to sustain a 300,000-bbl-per-day industry. Private land in Colorado and Utah, owned by major oil companies, contains enough thick, rich oil shales to produce an additional 550,000 bbl of oil per day. Known deposits outside the United States contain a large enough resource base to maintain a 2.2-million-bbl-per-day shale-oil industry. In addition, some developing countries that have oil-shale deposits of lesser magnitude may establish labor-intensive, less expensive industries with smaller rates of production. End_of_Article - Last_Page 700------------

Fracturing Oil Shale With Electricity

Abstract Laboratory studies to evaluate the use of electricity for fracturing various grades of Colorado oil shale were started in 1964. Breakdown voltages varied greatly from one grade of shale to another, ranging from a minimum of 300 v to a maximum of 15,000 v. With few exceptions, the shale samples were readily fractured at relatively low current levels. On the basis of encouraging results obtained in the laboratory, experiments were expanded to field tests to study electrical characteristics of oil shale when subjected to overburden pressure. These tests generally confirmed the laboratory experiments. Fracturing was accomplished at all electrode spacings used. The spacings varied from 3 to 129 ft. Based upon results obtained in these field experiments, additional fracturing tests were conducted in four shallow wells drilled in an oil shale formation. Some new permeable zones were created between wells. The induced permeability was improved by detonating two conventional nitroglycerin wellbore shots in one of the wells. Introduction Before an in situ retorting process can function, it is necessary to develop techniques to increase the permeability of the oil shale formation. Induced fracturing, the best method of increasing the effective permeability of oil-shale deposits, may be accomplished by hydraulic pressure, high explosives, high-voltage electricity or combinations of two or more of these. This article discusses the laboratory experiments and preliminary field tests being made to study high-voltage electricity as a method of fracturing oil shale. Fracturing is the first phase of the electrocarbonization process and is the phase with which this investigation is primarily concerned. Several investigators have studied the electrocarbonization process as applied in coal, petroleum and oil shale formations, but none has reported making field tests in Green River oil shale. Laboratory Experiments Preliminary Studies Samples used for the preliminary tests to evaluate electrical properties of various types of oil shale ranged in size from 2 to 175 lb and represented a broad spectrum of Colorado oil shales ranging from 1.5 to 58.6 gal of oil per ton of shale. The first tests determined the breakdown voltage required to initiate a current flow of 5 milliamp through the sample. In all cases, 1/4-in. stainless steel tubes spaced 4 in. apart were used as the electrodes. Breakdown voltages varied greatly from one sample to another, ranging from 300 to 15,000 V. Fracturing Studies Establishment of Air Communication After it was definitely established that electrical fracturing could be accomplished, other factors related to an in situ retorting process were investigated. The first of these was the establishment of air communication between two or more holes drilled at different locations in the shale block. Experiments were conducted on several shale blocks in which three holes were drilled in a line and spaced 2 in. apart, with 1/4-in. perforated steel tubes cemented into the holes. In most cases, interconnecting fractures created by the electrical current permitted substantial amounts of air to flow between all three holes. In these experiments the entire length of the steel tubes served as the electrodes; under these conditions the fractures occurred at random along the low-resistance paths taken by the electric current. Controlled Fracturing Fracturing at random is not a satisfactory solution to the problem. For an in situ retorting operation to be successful, a technique is required to create a system of horizontal fractures vertically spaced at preselected intervals. Accurate control of positioning the horizontal fractures is essential because the combustion process may require a vertical spacing between fractures of as little as 1 or 2 ft In Feb., 1965, experiments were initiated to investigate the feasibility of creating a controlled system of horizontal fractures. Electrodes used in these experiments were designed to concentrate the current at a small, well defined contact point. The first experiments were made with slabs of oil shale weighing 150 to 300 lb. Horizontal fractures were induced at preselected levels vertically spaced at 3-in. intervals (Fig. 1). Based on these results the experiments were expanded to involve oil shale slabs weighing several tons. The slab shown in Fig. 2 assayed at 55.7 gal of oil per ton. The top of the slab was first leveled off by inducing a fracture at the base of the peak. Two 1-in. diameter holes spaced 4 ft apart were drilled to a depth of 36 in. JPT P. 37ˆ

XVIII.— Note on Fused Spent Shale from a Retort at Pumpherston, Midlothian

The materials described in this note were submitted by Mr. H. R. J. Conacher of Scottish Oils, Ltd., who thought it possible that the mineral changes occurring in them as a result of thermal action would prove of general interest. One set of specimens (Series I) included lumps of partly fused spent shale and of the contiguous firebrick of the retort wall, and was obtained during the demolition of retorts at Pumpherston. The actual oil-shale which the material represents cannot be definitely identified because the retort had been in operation for some thirty years. The other set of specimens (Series II) consisted of two samples of shale, which had been subjected to a temperature of 1,400° F. in the presence of steam equivalent to 60 gallons of water per ton of shale, one sample (A) having experienced this treatment in presence of air equivalent to about 4,000 c. ft. per ton of shale, the other sample (B) having been treated in the absence of air. A superficially fused SOL brick, which is manufactured from spent shale to which about 10 per cent. of lime has been added, accompanied the samples (A) and (B). The oil-shale seam which the latter represent is not known; but the spent shale from which the SOL brick was made was probably derived from the Pumpherston Shales which contain somewhat more lime and magnesia than the other seams. Series I. The fused shales. —One specimen (S 34619) is composed of fragments of shale embedded in a black This 250-word extract was created in the absence of an abstract

Brick-making with low grade oil shale at Hailes Quarry, Edinburgh

Hailes Quarry, situated on the south-western outskirts of the city, near Slateford, has long been known for the excellent quality of its sandstone. This building stone is no longer worked except to a very limited extent, but the shales above are at present being used on a large scale for brick-making. At present (1928) there is a working face of about 70 feet of shale above the sandstone. With the exception of a few thin bands of flaggy sandstone interbedded with it, the whole of this thickness is used for brick-making. The most valuable part of the mass, however, is the twelve feet or thereby of poor oil shale nearest the sandstone. This poor oil shale at Hailes was recorded in 1906 by Messrs Crampton and Tait in our Transactions.1 They give the following particulars regarding it. It yields 8.32 gallons of crude oil per ton of shale. Its setting point is 85°, and it yields 20.89 lbs. of sulphate of ammonia per ton of shale. They also record other localities for poor oil shale on much the same horizon at Wardie and Granton. These poor oil shales underlie all the oil shale seams that have been worked. When bricks made of this poor oil shale are being fired, gas, or vapour, streams from openings in the kiln. Evidently the oil or kerogene contained in the raw material of the brick passes into a gaseous condition and assists the burning of the brick. By the aid of this oil or