Chlorites in reservoir sandstones of the Guadalupian Delaware Mountain Group
- Texas A and M Univ., College Station (United States)
Late-stage authigenic clay minerals are pervasive in the very fine-grained, subarkosic sandstones of the Guadalupian Delaware Mountain Group, comprising up to 10% of the bulk rock. Thus, reservoir rock properties are influenced by these minerals. Samples selected from cored intervals, ranging from 600 to 2500 m, were studied using optical and electron microscopy and x-ray diffraction methods to determine the distribution and nature of occurrence of the authigenic clay minerals. In thin sections, the clay minerals are recognizable as grain coatings, with thickness varying from a few micrometers to tens of micrometers. A correlation between the morphology and the amount of interstratification has been observed, with more interstratification corresponding to the formless chlorite variety. The structural and morphological evidence suggests that the chlorites represent different stages of development, possibly evolving from a smectite component through an interstratified intermediate, to a more well-ordered form. There appears to be no systematic trends vertically or laterally in clay mineralogy. The importance of understanding the clay mineralogy and chemistry in these sandstones is evident when considering enhanced recovery procedures. Different clay structures and chemistries may respond differently to production and stimulation techniques. The proposed chlorite diagenetic sequence suggests that drastic changes in borehole fluid chemistry may cause retrogression of chlorite to some expansive forms, which may be water sensitive or inclined to migration.
- OSTI ID:
- 7195473
- Report Number(s):
- CONF-9204139-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 76:4; Conference: American Association of Petroleum Geologists (AAPG) Southwest section meeting, Midland, TX (United States), 21-24 Apr 1992; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
CHLORITE MINERALS
STRUCTURAL CHEMICAL ANALYSIS
PERMIAN BASIN
PETROLEUM DEPOSITS
MINERALOGY
PETROGRAPHY
CLAYS
DIAGENESIS
ELECTRON MICROSCOPY
ENHANCED RECOVERY
GEOLOGIC FORMATIONS
PERMEABILITY
POROSITY
RESERVOIR ENGINEERING
RESERVOIR ROCK
ROCK-FLUID INTERACTIONS
X-RAY DIFFRACTION
COHERENT SCATTERING
DIFFRACTION
ENGINEERING
GEOLOGIC DEPOSITS
MICROSCOPY
MINERAL RESOURCES
MINERALS
RESOURCES
SCATTERING
SILICATE MINERALS
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences