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C. G. Dodd

Bio: C. G. Dodd is an academic researcher. The author has contributed to research in topics: Petroleum reservoir. The author has an hindex of 1, co-authored 1 publications receiving 19 citations.

Papers
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Journal ArticleDOI
TL;DR: The ability of some petroleum reservoir sands to conduct oil is decreased by interaction of the porous rock with water, usually water fresher than that coexisting with oil in rock interstices as discussed by the authors.
Abstract: The ability of some petroleum reservoir sands to conduct oil is decreased by interaction of the porous rock with water, usually water fresher than that coexisting with oil in rock interstices. Shales penetrated by drilling operations may swell upon interaction with relatively fresh water drilling liquids. The question of the relation of specific clay mineral content to reservoir sand water sensitivity has not been investigated in detail by other workers, although bentonitic clays often have been considered responsible.

21 citations


Cited by
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Book ChapterDOI
01 Jan 1975
TL;DR: In this article, it was verified that this irregularity was due to the interstratification of different types of crystalline layers, which is a phenomenon that was first observed on studying clay minerals by X-ray diffraction.
Abstract: Interstratification is a phenomenon that was first observed on studying clay minerals by X-ray diffraction. It was noted that the majority of them had basal reflections (001), which did not form a regular series. It was verified that this irregularity was due to the interstratification of different types of crystalline layers.

184 citations

Journal ArticleDOI
01 Sep 2015-GeoResJ
TL;DR: In this article, the authors combined core-flood experiments with X-ray μ-computed tomography (μ-CT) to investigate the swelling of clay minerals and its impact on the permeability of unconsolidated porous media.

127 citations

Journal ArticleDOI
TL;DR: In this paper, the authors explore friction-stability-permeability relationships through the concurrent measurement of frictional and hydraulic properties of artificial fractures in Green River shale (GRS) and Opalinus shale (OPS).
Abstract: There is wide concern that fluid injection in the subsurface, such as for the stimulation of shale reservoirs or for geological CO2 sequestration (GCS), has the potential to induce seismicity that may change reservoir permeability due to fault slip. However, the impact of induced seismicity on fracture permeability evolution remains unclear due to the spectrum of modes of fault reactivation (e.g., stable versus unstable). As seismicity is controlled by the frictional response of fractures, we explore friction-stability-permeability relationships through the concurrent measurement of frictional and hydraulic properties of artificial fractures in Green River shale (GRS) and Opalinus shale (OPS). We observe that carbonate-rich GRS shows higher frictional strength but weak neutral frictional stability. The GRS fracture permeability declines during shearing while an increased sliding velocity reduces the rate of permeability decline. By comparison, the phyllosilicate-rich OPS has lower friction and strong stability while the fracture permeability is reduced due to the swelling behavior that dominates over the shearing induced permeability reduction. Hence, we conclude that the friction-stability-permeability relationship of a fracture is largely controlled by mineral composition and that shale mineral compositions with strong frictional stability may be particularly subject to permanent permeability reduction during fluid infiltration.

111 citations

Journal ArticleDOI
D. H. Gray1
TL;DR: In this article, X-ray diffraction and electron microscopy were employed in conjunction with core flooding experiments to investigate clay migration phenomena in sandstones of 500 millidarcy permeability.
Abstract: X-RAY diffraction and electron microscopy were employed in conjunction with core flooding experiments to investigate clay migration phenomena. Severe water sensitivity or loss of permeability was observed in a suite of sandstones in spite of the almost total absence of montmorillonite or swelling mixed layer clays. Clay migration was found to cause total or partial plugging even in sandstones of 500 millidarcy permeability. Bacterial plugging was ruled out by prefiltering and bactericide treatments of waters. X-ray diffraction and electron microscopy analyses were performed on the sandstones and produced effluents. The direct cause of damage was displacement of submicroscopic natural clay crystals of needle-shaped mica and hexagonal-shaped kaolinite (Rex, 1965). The mobile clays were identified as authigenic crystals that are present on the pore walls and are dislodged by changes in water chemistry combined with water movement. Flooding sandstones with alkali metal brines “sensitized” the cores, i.e. triggered clay dispersion upon subsequent flooding with fresh water. Flooding with divalent calcium brine prevented water sensitivity and suppressed the undesirable effect of alkali metal brines. A double layer expansion effect is suggested as the dispersion mechanism.

86 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the detrital basic lattice is not altered to a measurable extent in Recent marine sediments. But, it remains to be proved whether this is caused by chemical modification of the basic lattices with burial, or if the Detrital clay lattice has the inherent ability to contract, without chemical rearrangement, when buried to a sufficient depth.
Abstract: Studies of the Recent indicate that, at the most, somewhat less than half the clay minerals are altered to any extent in a marine environment. Probably most of this alteration is in the form of cation adsorption or reconstitution of slightly weathered illites and chlorites to their original form. There appears to be little if any evidence that the detrital basic lattice is being altered to a measurable extent in Recent marine sediments. In the near-shore environments there is usually a coincidence of clay mineral suites and environments. A major change in the clay mineral composition of sedimentary rock occurs within the Mississippian. Illite is the dominant clay mineral of the pre-Upper Mississippian sediments. Post-Lower Mississippian clay suites are more variable in composition; illite becomes less abundant and montmorillonite and kaolinite more abundant. This change is best related to a change in regional tectonics. The clay minerals seem to have no preferred lithologie associations, although owing to epigenetie alterations porous sandstones commonly have different clay mineral suites from those of adjacent shales and carbonate rocks. In many instances clay mineral facies coincide with environmental facies. As the clay mineral criteria for distinguishing any given type environment are extremely variable, it is thought that segregation of clay mineral suites by sorting is usually more effective than by diagenesis. Expanded clay minerals appear to be partially contracted by the time they have been buried to 10,000–15,000 ft. It remains to be proved whether this is caused by chemical modification of the basic lattice with burial or if the detrital clay lattice has the inherent ability to contract, without chemical rearrangement, when buried to a sufficient depth.

85 citations