Characteristics and diagenesis of platform margin reef-shoal reservoirs of Upper Permian Changxing Formation around Kaijiang-Liangping Trough, eastern Sichuan Basin

SU Cheng-peng; TAN Xiu-cheng; LIU Hong; TANG Hao; LI Hong-wei; WANG Gao-feng; TANG Xue-song; ZHANG Qi-ye; LIAO Yi-sha

doi:10.12029/gc20160615

2016 Vol. 43, No. 6

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Article navigation > Geology in China > 2016 > (6): 2046-2058

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SU Cheng-peng, TAN Xiu-cheng, LIU Hong, TANG Hao, LI Hong-wei, WANG Gao-feng, TANG Xue-song, ZHANG Qi-ye, LIAO Yi-sha. Characteristics and diagenesis of platform margin reef-shoal reservoirs of Upper Permian Changxing Formation around Kaijiang-Liangping Trough, eastern Sichuan Basin[J]. Geology in China, 2016, (6): 2046-2058. doi: 10.12029/gc20160615

Citation:

SU Cheng-peng, TAN Xiu-cheng, LIU Hong, TANG Hao, LI Hong-wei, WANG Gao-feng, TANG Xue-song, ZHANG Qi-ye, LIAO Yi-sha. Characteristics and diagenesis of platform margin reef-shoal reservoirs of Upper Permian Changxing Formation around Kaijiang-Liangping Trough, eastern Sichuan Basin[J]. Geology in China, 2016, (6): 2046-2058. doi: 10.12029/gc20160615

Characteristics and diagenesis of platform margin reef-shoal reservoirs of Upper Permian Changxing Formation around Kaijiang-Liangping Trough, eastern Sichuan Basin

1.
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China;Sedimentary and Accumulation Department of Key Laboratory of Carbonate Reservoirs, PetroChina, Southwest Petroleum University, Chengdu 610500, Sichuan, China
2.
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China;Sedimentary and Accumulation Department of Key Laboratory of Carbonate Reservoirs, PetroChina, Southwest Petroleum University, Chengdu 610500, Sichuan, China;Key Laboratory of Natural Gas Geology, Southwest Petroleum University, Chengdu 610500, Sichuan, China
3.
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China;Key Laboratory of Natural Gas Geology, Southwest Petroleum University, Chengdu 610500, Sichuan, China
4.
Chongqing Gas Production Plant, PetroChina Southwest Oil & Gas Field Company, Chongqing 400021, China

Received Date: 17 September 2015

Revised Date: 29 November 2015

Publish Date: 24 December 2016

Abstract

Abstract

In this paper, the authors utilized cores and thin sections observations, SEM, cathodoluminescence and physical property analysis to study characteristics and diagenesis of the reservoir within Upper Permian Changxing Formation, and preliminarily established diagenetic evolution sequence. The interval is mainly featured by platform margin reef-shoal around KaijiangLiangping trough in eastern Sichuan Basin. Reservoir characteristics reveal that the Changxing reservoirs are developed well. Reservoir rocks are composed of"piebald"bioclastic dolomite and reef dolomite dominate, whereas reservoir spaces mainly comprise intergranular pores, dissolved intergranular pores and dissolved intragranular pores. The reservoir porosity is mainly between 2% and 6%, and the permeability is between 0.1 mD and 1 mD. Four types of reservoirs were found, i.e., "low-porosity and high-permeability" type, "medium-porosity and medium-permeability" type, transitional type and "high-porosity and lowpermeability" type. The diagenetic evolution indicates that Changxing Formation experienced cementation, compaction, dolomitization, dissolution and tectonic fracturing. A decreasing trend in porosity due to the superimposed modification by multiplephase diagenesis was observed. Cementation and compaction occupied most of primary pores and reduced the porosity after the deposition. Karstification and dolomitization improved the porosity by transforming the textures of pores. Tectonic fractures further optimized the reservoir. Research shows that primary intergranular pores and eogenetic secondary pores formed by eogenetic karstification and hydrothermal dolomitization not only serve as the prototype of reservoir space but also generally determine the final appearance of the reservoir.
- reef-shoal reservoirs /
- diagenesis /
- eogenetic karstification /
- hydrothermal dolomitization /
- Changxing Formation /
- eastern Sichuan Basin