Key Role of High-quality Source Rocks on the Formation of Low-permeability Oil-rich Reservoirs in Ordos Basin(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2013年第04期
- Page:
- 1-9
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Key Role of High-quality Source Rocks on the Formation of Low-permeability Oil-rich Reservoirs in Ordos Basin
- Author(s):
- YANG Hua; ZHANG Wen-zheng; LIU Xian-yang; LI Shan-peng; SHAO Chuang-guo
- 1. National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields, Changqing Oilfield Company, PetroChina, Xi’an 710018, Shaanxi, China; 2. Changqing Oilfield Company, PetroChina, Xi’an 710018, Shaanxi, China; 3. Research Institute of Exploration and Development, Changqing Oilfield Company, PetroChina, Xi’an 710018, Shaanxi, China
- Keywords:
- source rock; low-permeability; reservoir-forming dynamic; hydrocarbon-bearing fluid; Yanchang Formation; Mesozoic; Ordos Basin
- PACS:
- P618.13;TE122
- DOI:
- -
- Abstract:
-
Mesozoic low-permeability oil reservoirs are extensively distributed in Ordos Basin, mainly in all members of Yanchang Formation, and Chang-6, Chang-8and Chang-4+5 are the dominating reservoirs. The data from pyrolysis of reservoir rocks show that the oil-rich features of deep water facies compact sandstone bodies of Chang-7and Chang-6in the central part of lake basin are favorable, oil reservoirs are universal in these members, which enable the lake basin to be oil-rich and low-permeability at full basin scale. Rate-controlled mercury, startup pressure gradient and oil infilling tests for reservoir show that gravitational differentiation of oil and water in reservoirs is very difficult, because the sandstone reservoirs of Yanchang Formation are low-permeability and tight, and consist of tiny migration channels which show high capillary resistance, and the stratum is only relatively slowly inclined. Oil migration and accumulation appear to be passive in terms of dynamic attribute, since oil infilling and large-scale migration, accumulation and reservoir formation require strong dynamics as well as hydrocarbon-bearing fluid.Chang-7high-quality source rock, which is distributed extensively on large scale in the basin, is capable of large-scale hydrocarbon generation and expulsion, strong hydrocarbon-generating pressurization and efficient hydrocarbon expulsion. Hydrocarbon-generating pressurization provides the power of oil migration and accumulation, and hydrocarbon expulsion provides large-scale hydrocarbon-bearing fluid. So, it can satisfy the dynamics and oil-source conditions as required for formation of large-scale low-permeability and tight sandstone reservoirs, and play a key role in formation of Mesozoic low-permeability and oil-rich reservoirs in Ordos Basin.
Last Update: 2014-01-20