Xinjiang Petroleum Geology ›› 2023, Vol. 44 ›› Issue (5): 509-516.doi: 10.7657/XJPG20230501

• OIL AND GAS EXPLORATION •     Next Articles

Natural Gas Enrichment in Carbonate Gas Reservoirs of Taiyuan Formation in Yishaan Slope,Ordos Basin

LI Yanrong1(), LI Jing2a, SU Wenjie2b, SHI Lei2b, SUN Rui1, ZHU Yushuang1()   

  1. 1. Northwest University, a.State Key Laboratory of Continental Dynamics; b.Department of Geology, Xi'an, Shaanxi 710069, China
    2. PetroChina Changqing Oilfield Company, a.Exploration Department; b.No.2 Gas Production Plant, Xi'an, Shaanxi 710018, China
  • Received:2023-04-11 Revised:2023-05-04 Online:2023-10-01 Published:2023-09-25

Abstract:

To determine the distribution of the carbonate gas reservoirs in Permian Taiyuan formation in Yishaan slope of the Ordos basin, based on the data of drilling, well testing, logging, and formation testing, the carbonate gas reservoirs in Taiyuan formation were analyzed using field outcrops, core samples, thin sections, electron microscopy scanning, high-pressure mercury intrusion, and fluid inclusion temperature measurements, and then sedimentary microfacies, petrographic characteristics, physical properties, pore structures, and fracture distribution were studied of the reservoir. The results indicate that the carbonate gas reservoirs in Taiyuan formation are low-porosity and low-permeability lithological gas reservoirs. Favorable plays control the reservoir distribution and gas enrichment. The gas reservoirs `are mainly distributed in the bioherm and bioclastic shoal microfacies zones. Bioherms are found in the eastern part of the study area, including Jiaxian, Zizhou, and Qingjian, while bioclastic shoals are developed in the western part of the study area, including Hengshan, Jingbian, and Pingqiao, exhibiting an obvious zoning of facies from west to east. The carbonate rocks in Taiyuan formation consist of micritic bioclastic limestone and algal-bounded limestone, in which biogenic pores, intercrystalline pores, dissolution pores, and microcracks serve as accommondation. Fractures play a crucial role in migration of oil and gas, and their development contributes significantly to the natural gas enrichment in the reservoirs.

Key words: Ordos basin, Yishaan slope, Permian, Taiyuan formation, carbonate, gas reservoir, natural gas, natural gas, enrichment

CLC Number: