Orientation of fracture is a key parameter affecting effective development of fractured reservoir, but it is hard to ascertain the fracture trend of non-oriented cores. The paleomagnetic method is an effective core orientation technique developed in recent years, and its application in volcanic rocks and some of the argillaceous rocks with larger remnant magnetization intensity has achieved good performance. However, its use in the carbonate rocks with weak magnetization is rarely studied. Based on a systematic test of isothermal remnant magnetization and thermal demagnetization of the weak magnetic carbonate core samples from Jiyang depression, this paper successfully obtains the viscous magnetic remnants and identifies the rough development orientation of the fracture in this region: Two major groups NEE and NNW, and three minor groups NWW, NW and NNE. The fracture orientation from this core test is consistent with FMI data and tectonic stress field analysis results. The research results expand the application of the palaeomagnetic orientation in the weakly magnetic cores.
Sun Zhiyong Chen Kaiyuan Du Yushan Wang Yuqin Sui Shuling . Study on paleomagnetic fracture orientation of weakly magnetic carbonate cores in Jiyang depression[J]. Chinese Journal of Geology, 2017, 52(3): 954-963.