Natural fracture prediction in Keshen 2 ultra-deep tight gas reservoir based on R/S analysis, Kuqa Depression, Tarim Basin.

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Date: Aug. 2021
From: Geosciences Journal(Vol. 25, Issue 4)
Publisher: Springer
Document Type: Report; Brief article
Length: 347 words

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Keywords: natural fracture; ultra-deep tight gas; R/S analysis; Keshen 2 Block; Bashijiqike Formation; Kuqa Depression Abstract Within ultra-deep tight sandstone gas reservoirs, natural fractures indicate significant effects on reservoir performance because they can serve as storage spaces for hydrocarbons and improve the permeability. Accurate prediction of natural fractures in ultra-deep reservoirs is critical to the exploration and development of tight gas in Keshen 2 Block of Kuqa Depression. In this study, several conventional logs are selected and the R/S analysis method is introduced to predict the development and distribution of natural fractures in ultra-deep tight sandstone reservoirs. Fracture development coefficient Q is calculated based on the second derivatives of lg(R/S) function and corresponding weight of each log parameter, which matches well with linear fracture density measured from image logs. There is a positive correlation between parameter Q and fracture density, higher Q values usually indicate larger fracture density. Factors causing mismatches between calculated parameter Q and fracture density are also analyzed. Fracture dip angle, fracture filling condition, vertical resolution of logs, multiple interpretations of conventional logs, and lateral detection difference between image and conventional logs may contribute to generate those false appearances. The results in this study are expected to provide new geological references for the exploration and development of ultra-deep tight gas in Keshen 2 Block of Kuqa Depression. Author Affiliation: (1) Institute of Exploration and Development, PetroChina Tarim Oilfield Company, 841000, Korla, China (2) School of Resources and Geosciences, China University of Mining and Technology, 221116, Xuzhou, China (3) Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Mineral, Shandong University of Science and Technology, 266590, Qingdao, China (4) School of Computer Science and Technology, China University of Mining and Technology, 221116, Xuzhou, China (5) PetroChina Hangzhou Research Institute of Geology, 310023, Hangzhou, China (b) wju@cumt.edu.cn Article History: Registration Date: 11/28/2020 Received Date: 04/29/2020 Accepted Date: 09/23/2020 Online Date: 12/03/2020 Byline: Hui Zhang (1), Wei Ju (corresponding author) (2, 3, b), Guoqing Yin (1), Xinyu Liu (1), Zhimin Wang (1), Sijia Liu (4), Ke Wang (5), Hui Yang (2), Ke Xu (1), Wenbo Luan (2)

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Gale Document Number: GALE|A667925778