Characteristics and Forming Mechanism of Palaeokarst Reservoir of Majiagou Formation in Yichuan-Huanglong Area of Ordos Basin, China(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2019年第01期
- Page:
- 83-95
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Characteristics and Forming Mechanism of Palaeokarst Reservoir of Majiagou Formation in Yichuan-Huanglong Area of Ordos Basin, China
- Author(s):
- FANG Ji-yao; CHEN Hong-de; SHI Yun-he; LI Lei; DENG Xiang; SU Zhong-tang
- 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, Sichuan, China; 2. Sichuan Province Key Laboratory of Shale Gas Evaluation and Exploitation, Chengdu 610091, Sichuan, China; 3. Research Institute of Exploration and Development, Changqing Oilfield Company, PetroChina, Xi’an 710018, Shaanxi, China
- Keywords:
- palaeokarst; reservoir; main controlling factor; karst landform; multi-stage filling; dedolomitization; forming mechanism; Ordos Basin
- PACS:
- P618.13;TE122
- DOI:
- -
- Abstract:
- The Yichuan-Huanglong area in Ordos Basin has favorable prospect for exploration, which is of great significance for the exploration of Huanglong gasfield to study the main controlling factors and forming mechanism of reservoir. Based on the core observation, casting thin section identification, cathodoluminescence(CL) and geochemical test analysis, combined with the drilling and logging data, the basic characteristics, main controlling factors and forming mechanism of palaeokarst reservoirs of Majiagou Formation in Yichuan-Huanglong area were studied. The results show that the powder crystal gypsodolomite, powder crystal doloarenite and powder-aplitic crystal dolomite mainly develop in the area; the gypsum mold pore, intergranular hole, solution pore and solution fissure are the most important reservoir spaces; the reservoir porosity is mainly from 0.1% to 5.0%, and the permeability is mainly from 0.002×10-3 μm2 to 0.100×10-3 μm2, with low to extra-low porosity and permeability; the distribution of favorable reservoirs is affected by various geological processes, the anhydrite-bearing concretion dolomite flat, dolomite flat and grain bank microfacies are the foundation of development of high quality reservoir, the plane distribution of reservoirs is controlled by the palaeokarst geomorphology, the vertical distribution is controlled by karst cycle, the favorable reservoirs distribute in the vertical permeating belt of the supergene, and the effective porosity is reduced by the dedolomitization in the later stage of diagenesis and three stages of different types of filling, which are the direct factor of poor physical property of reservoir in the area.
Last Update: 2019-01-25