Xinjiang Petroleum Geology ›› 2025, Vol. 46 ›› Issue (1): 78-87.doi: 10.7657/XJPG20250110

• RESERVOIR ENGINEERING • Previous Articles     Next Articles

Geological Characteristics and Development Technologies of Shale Gas Field in Anchang Area, Guizhou Province

LIU Honglin1(), LU Dan2, LIANG Feng1, HE Xinbing2, LI Gangquan2, ZHAO Qun1, BAI Wenhua1   

  1. 1. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
    2. Guizhou Shale Gas Exploration and Development Co., Ltd., Zunyi, Guizhou 563499, China
  • Received:2024-04-28 Revised:2024-09-30 Online:2025-02-01 Published:2025-01-24

Abstract:

The shale gas field in Anchang area in the northern part of Guizhou province is primarily producing from the shales in the Wufeng formation to Longmaxi formation. This gas field is characterized by a source-reservoir integrated system in stable distribution and self-generation and self-storage pattern, and it is classified as a shallow mountainous shale gas field under normal pressure. From top to bottom, the gas-bearing layers show an increasing content of siliceous minerals and a decreasing content of clay minerals. The shale reservoir space primarily consists of nanometer-scale organic pores, followed by residual intergranular pores, intercrystalline pores, secondary dissolution pores, and clay mineral interlamellar pores. The gas wells generally exhibit low flowback rates upon gas breakthrough, slow production decline, and long stable production period. Considering the geological and developmental characteristics of this type of gas reservoir, it is important to enhance detailed geological modeling and fracturing design optimization, as well as to moderately expand well spacing. Given the presence of faults and strong heterogeneity, integrated geological and engineering design should be strengthened, and the 3D reservoir geological model should be iteratively optimized to establish an accurate shale gas reservoir model. In view of the large differential horizontal stress ratios and the difficulty in forming complex fracture networks, fracturing stage length and cluster spacing should be optimized, and multi-cluster fracturing and fracture diversion techniques can be implemented. For low reservoir pressure, fast decline in wellhead pressure, and low gas production, the flowback management system in the gas testing stage should be further optimized.

Key words: Guizhou province, Anchang area, shale gas, Longmaxi formation, shale, normal-pressure gas field, pore structure

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