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Controls of Acid‐sensitive Minerals on Reservoir Sensitivity Testing: An Example from the Silurian Kepingtage Formation in Tazhong Area, Tarim Basin
Author(s) -
HAN Denglin,
WANG Qianqian,
WANG Chenchen,
OUYANG Chuanxiang,
YUAN Wenfang
Publication year - 2018
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13689
Subject(s) - dolomite , pyrite , chlorite , calcite , clay minerals , tarim basin , permeability (electromagnetism) , mineralogy , geology , mineral , chemistry , geochemistry , quartz , membrane , organic chemistry , paleontology , biochemistry
The Silurian Kepingtage Formation in Tazhong area is regarded as an acid‐sensitive hydrocarbon reservoir. However, formation mechanism of acid‐sensitive of the reservoir cannot be interpreted by the existing acid‐sensitive evaluation criterion based on damage rate. The contents of acid ‐sensitive minerals illustrated by bulk‐rock XRD, scanning electron microscopy and clay mineral composition analysis exert the dominant control on acid‐sensitive flow testing of the reservoir. The iron‐ bearing minerals (including pyrite cements and chlorite cements) mainly deteriorate reservoir quality, while the iron‐free minerals (including calcite cements and dolomite cements) mainly improve permeability. The permeability variation of the tested samples is controlled by the relative content of two acid‐sensitive minerals. On the basis of newly established sensitivity mechanism and its influence on permeability, the corresponding ion (Fe 2+ ) stabilizer was added to the acidizing fluids during the acidification reconstruction, which inhibited the negative factors of acid‐sensitive minerals and improved the target layer quality effectively.