Geological Controlling Factors of Low Resistivity Shale and Their Implications on Reservoir Quality: A Case Study in the Southern Sichuan Basin, China

Xinhua Ma, Hongyan Wang, Tianqi Zhou (), Qun Zhao, Zhensheng Shi, Shasha Sun and Feng Cheng
Additional contact information
Xinhua Ma: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China
Hongyan Wang: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China
Tianqi Zhou: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China
Qun Zhao: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China
Zhensheng Shi: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China
Shasha Sun: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China
Feng Cheng: PetroChina Research Institute of Petroleum Exploration Development, Beijing 100083, China

Energies, 2022, vol. 15, issue 16, 1-24

Abstract: At the Changning block and at the Luzhou block, the genetic mechanism of low-resistivity shale and its impact on reservoir quality are currently a hot topic on a world-wide scale. Shale with resistivity lower than 20 Ω·m is widely developed at the Wufeng-Longmaxi Formation in the Southern Sichuan Basin, bringing a considerable challenge for reservoir prediction using the electromagnetic method. This paper discusses the genetic mechanisms and reservoir qualities of three low-resistivity shale reservoir types in the Southern Sichuan Basin (the Changning block and Luzhou block). Three primary elements controlling low-resistivity shale distribution in the Southern Sichuan Basin have been deduced: widely distributed gravity flow deposits, poor structural preservation conditions and shale graphitization caused by Emeishan basalt. Specifically, (1) the shale reservoir with a resistivity <12 Ω·m was uniformly distributed with gravity flow deposits in the Southern Sichuan Basin. High clay mineral contents (especially illite) in gravity flow deposits increased cation exchange capacity and irreducible water saturation at shale reservoir, decreasing electrical resistivity. (2) The resistivity of the shale reservoir close to a complex fault-fracture zone was generally lower than 20 Ω·m, indicating that poor structural preservation conditions played an important role in the wide distribution of low-resistivity shale. The resistivity of the shale reservoir near NE-trending faults at the Changning block was significantly lower than that in other areas. (3) Emeishan basalt caused extensive shale graphitization at the west of the Changning block, which was limited at the Luzhou block. The shale resistivity at the Luzhou block was not affected by graphitization. Among three types of low-resistivity shale, type III was characterized by high quartz content, high TOC, high porosity, high gas content and low graphitization. Although the resistivity of type III is generally lower that 20 Ω·m, it is still a favorable exploration target in the Southern Sichuan Basin.

Keywords: organic shale; electrical properties; Sichuan Basin; reservoir quality (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/15/16/5801/pdf (application/pdf)
https://www.mdpi.com/1996-1073/15/16/5801/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:15:y:2022:i:16:p:5801-:d:884890

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().