Development Characteristics of Fractures in the Middle-Lower Jurassic Tight Oil Reservoirs in Central Sichuan Basin(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2016年第02期
- Page:
- 226-234
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Development Characteristics of Fractures in the Middle-Lower Jurassic Tight Oil Reservoirs in Central Sichuan Basin
- Author(s):
- LU Wen-ya; ZENG Lian-bo; ZHANG Jun-hui; CHEN Shuang-quan; HUANG Ping; LU Peng; MI Hua-cun
- 1. College of Geosciences, China University of Petroleum, Beijing 102249, China; 2. Exploration and DevelopmentResearch Institute of Southwest Company, SINOPEC, Chengdu 610041, Sichuan, China; 3. College of Geophysics and Information Engineering, China University of Petroleum, Beijing 102249, China; 4. Exploration and Development Research Institute of Southwest Company, PetroChina, Chengdu 610051, Sichuan, China; 5. Yumen Oilfield Company, PetroChina, Jiuquan 735200, Gansu, China
- Keywords:
- fracture; tight oil reservoir; development characteristic; intensity; sample bias; highdip angle; MiddleLower Jurassic; Sichuan Basin
- PACS:
- P618.13;TE122
- DOI:
- -
- Abstract:
- Fractures are important storage space and fluid channels, influencing oilgas accumulation and well production in the Middle-Lower Jurassic tight oil reservoirs in central Sichuan Basin. Based on the data of analogous outcrops, cores and image logs, the fracture origin types and development characteristics were systematically analyzed. According to the geological origins, the tectonic and diagenetic fractures are developed in the Middle-Lower Jurassic tight oil reservoirs of the first member of Shaximiao Formation and Da’anzhai Formation in central Sichuan Basin, and the tectonic fracture is the main one. According to the dip angles of fractures, the fractures can be divided into three types, i. e. low dip-angle fractures (0°-30°), oblique dip-angle fractures (30°-60°) and high dip-angle fractures (more than 60°). Because low dip-angle fractures present high encountered rates in vertical wells, and oblique and high dip-angle fractures present gradual decrement of encountered rates, it is necessary to make a correction related to fracture intensity statistics. According to the spatial geometric relationship of fracture and core, the fracture number per meter of length in the normal direction of fracture surface was used to correct the calculation. The results show that the linear intensities of high dip-angle fractures are much greater than those of low dip-angle fractures in the first member of Shaximiao Formation and Da’anzhai Formation; high dip-angle fractures are the most abundant in these tight oil reservoirs; thus, it corrects the past understanding that low dip-angle fractures are the major, which is of great significance for further understanding fracture development rules and guiding tight oil exploration and development in this area.
Last Update: 2016-03-28