Shale formation

Potassium hydroxide [1310-58-3] is occasionaHy used for alkalinity control. This is particularly tme for some polymer and lime muds where a low sodium level is desired. The potassium level of such muds is quite low but has been attributed by some to provide stabHity to water-sensitive shale formations (68,93). 

A number of cationic muds have been developed and used. These ate formulated around quaternary amines or positively charged polymers (108,109). The polymer in some iastances may be a cationic polyacrylamide. Poly(dimethylarnine-fi9-epichloiohydrin) is another material that has been used successfiiUy for drilling shale formations (110,111). Some of these additives may requite a salt such as sodium or potassium chloride for best results. 

In onshore drilling there is no need for chlorides above these background levels. Potassium chloride has been added to some drilling fluids as an aid to controlling problem shale formations drilled. Potassium acetate or potassium carbonate are acceptable substitutes in most of these situations. 

Conglomerates and schists. Shales Formation Protection. Maintain low gels and thin filter cake. 

Equation 4-258 gives better results in most formations, particularly in unconsolidated formations. Both of these equations show a variation of the transit time with the porosity. Since the porosity increases in overpressured zones, the transit time increases. Figure 4-333 shows a typical plot for the shale formations of a well in Jefferson County, Texas. 

Driscoll, P.L., Bowen, J.G., and Roberts, M.A. "Oil Base Foam Fracturing Applied to the Niobrara Shale Formation," 1980 SPE Annual Fall Technical Conference and Exhibition of AIME, Dallas, September 21-24. 

At the present time we are conducting tests with electrical heaters in a sale mine in Louisiana, in a granite formation in Sweden, in a granite formation in Nevada and in shale formations both in Tennessee and Nevada. Early information developing from these heater tests will be used in the design of further, more sophisticated tests in which some of these geochemical interactions will be simulated. 

Robert B. Anderson Can you comment on Brook s postulate that alkaline environment leads to oil shale formation ... 

The literature on oil shale and shale oils is much richer and goes back several decades. However, because of its size and location, most of the literature deals only with one oil shale formation—the Green River Formation. 

Caliper and gamma ray logs were run to detect caving and borehole irregularities and to correlate the oil shale formations. Airflow tests were made to measure initial communication between injection well 6 and the remaining wells in the pattern. 

Tan, C. P., Drummond, C. J., Mody, F. K., and Tare, U. A. (2002). High membrane efficiency water-based drilling fluids Alternatives to invert emulsion fluids for drilling troublesome shale formations. In SPE Asia Pacific Oil and Gas Conference and Exhibition, Melbourne, Australia. 

There are historic reports of floods in the area (32 J. Rutherford, personal communication) and of an earthquake in 18 B.C. (33). The movement of the expansive Esna shale bed formation that underlies the whole area is also a source of disruption (32). The Esna shale bed formation, which contains montmorillonite clay, swells upon hydration by about 12.5% (32). Therefore, if an adequate amount of water is available, for example from increased irrigation, humidification, or flooding, the movement of this shale formation accelerates. Collectively, these dramatic natural events are the most probable causes of the loss of plaster and painted murals in the lower chamber of the tomb prior to its discovery, and they increasingly (32) threaten tombs in the Thebes area. 

These oil shales represent two trillion barrels of oil in Colorado, Utah, and Wyoming, and an additional one trillion barrels of oil of Devonian shale formation in the eastern United States. Eastern Devonian shale is quite different from western Green River shale. The noticeable differences are in geological age, kerogen structure, oil content, pyrite, and other mineral compositions. In the past, little effort has been focused on Devonian shales. However, the increasing role of eastern shales has now... 

Well logging Electrical surveys resistivity conductivity shale formation factor salinity variations Interval transit time Bulk density Hydrogen index Thermal neutron capture cross section Nuclear magnetic resonance Downhole gravity data After drilling... 

From the above-mentioned results with the oil shale retorting products, the pertinent question of whether the inorganic arsenic and organoarsenic compounds were actually natural products that were formed in the fossilization process of oil shale formation or were pyrolysis products formed during retorting, needed to be answered. 

This analysis of spent shale from a more formal viewpoint has verified many of the reactions and minerals that have been observed. The decarbonation reactions are realistic, the pyroxenes and olivines that are observed should be stable under the conditions of spent shale formation, and free quartz is readily used up to form the minerals found in spent shales. Also, the melilite which is ubiquitously found in spent shales appears to be a reasonable product, however more study should be made in the literature about melilite to see if it is stable under typical retort conditions. 

Figure 17. Carbon isotope fractionations as a function of metamorphic grade. (17A) Compilation of measured values of A(Cc-Gr) shows scatter and disequilibrium at greenschist facies and lower temperature conditions. Many amphibohte facies and most granuhte facies samples show a tight clustering of values consistent with isotope equilibration above 600°C. Values in black are from the Adirondacks (from Kitchen and Valley 1995). (17B) Values of 5 C for a Liassic black shale formation (Hoefs and Frey 1976) showing successive approach to equihbiium at maximum T = 500-600°C (from Sharp et al. 1995).

A more pervasive problem is the maintenance of wellbore stability in shale formations [i.e., formations that have a high clay content, typically in excess of 50 wt% (10)]. In the presence of water, shales can take up water and swell and disperse or they can fracture. Problems associated with wellbore stability in shale sections are sticking of the drill pipe (usually termed stuck pipe), hole enlargement, and excessive generation of drilled solids. 

Invert emulsion drilling fluids are commonly selected for their temperature stability and their ability to prevent the wellbore stability problems associated with the hydration of clays in shale formations. The thermodynamic activity aw of the water in the aqueous (dispersed) phase is controlled by the addition of a salt (usually calcium chloride) to ensure that it is equal to or less than the activity of the water in the drilled shale formations. The emulsified layer around the water droplets is claimed to act as a semipermeable membrane that allows the transport of water into and out of the shale but not the transport of ions (61). When the activities (or, more strictly, the chemical potentials) of the water in the shale and invert emulsion are equal, then no net transport of water into or out of the shale occurs (i.e., the drilling fluid does not hydrate or dehydrate the shale). This equality of water activity has lead to the development of so-called balanced activity oil-based drilling fluids. 

The basic problem of the interaction of drilling fluids with shale formations is an imbalance in the chemical potential of the water in the drilling fluid and in the shale. During the compaction of the shale, water is expelled and the clay-water ratio increases (see eq 96, for example). The presence of the exchange cations associated with the surface of the clay causes the water activity in the shale awsh to decrease as the water content decreases. The chemical potential / wsh of the water in the shale is given by... 

Larkin had a two-fold career, as member of the US Army, and also as successful civil engineer. In the latter field he was intimately connected with the Fort Peck Project. It was in the mid-1930s record-breaking in its proportions, namely a dam with 7x10 m hydraulieally plaeed earthfill, and the peeuliar structure of the basic shale formation through which the diversion tunnels and the spillway were built, as described in the 1935 paper. The main purpose of this projeet was to improve the Missouri River for navigation from Sioux City lA to St. Louis MO, but it had and still has also functions in flood control, and was extensively used for irrigation purposes. 

Natural gas is produced Ifom a variety of shale formations in the U.S., including the Barnett and Marcellus shales in Texas and the U.S. Northeast, respectively. As these resources have been developed, there has been an increasing public interest in greenhouse gas (GHG) emissions and water consumption associated with their extraction and use. 

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