Indentification and analysis of natural fracture and induced fracture in core: A case study of core fracture of Yanchang Formation in Ordos Basin
Jiang Lin1, Wang Qingchen2, Ge Jinming3, Hu Zhongjie4
1. School of Resource Engineering, Longyan University, Longyan, Fujian 364012;
2. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029;
3. Hainan institute of Geo-Environment Monitoring, Haikou, Hainan 570216;
4. PetroChina Huabei Oilfield Company, Renqiu, Hebei 602552
Although oriented and unoriented core provides the best opportunities for direct observation of fracture characteristics in subsurface reservoir rock, cost often limits its availability. Such restricted availability of core makes the accuracy of the information gained from such cores all the more critical. The identification of natural fractures from those induced fracture by production-related activities becomes a major obstacle in fractured core investigations. Taking the case study of core fracture of Yanchang Formation in the Ordos Basin, this paper provides a comprehensive review of the physical characteristics of natural and induced fracture. The paper focuses on analysisthe morphology, evolution of natural fracture, growth modes of induced fracture, and introduces terminology used to classify fracture and surface structures formed by foreign scholars. The fracture surface structure is the key to trace the dynamics of propagation of a mode I fracture(or joint)from inception to final arrest. It is useful in fractured core analysis as well as outcrop investigations.
. Indentification and analysis of natural fracture and induced fracture in core: A case study of core fracture of Yanchang Formation in Ordos Basin[J]. Chinese Journal of Geology, 2015, 50(3): 926-942.