Triassic middle oil-member favorite trap prediction in Akeyasu Area
Zhang Lei1,2, Wang Ying-min1,2, Yang Ting1,2, Liu Hao3, Zhang Xin-tao1,2, Zhu Yan-he1,2, Zhao Gang-feng1,2, Wang Gai-yun1,2
1. Faculty of Natural Resource and Information Technology, China University of Petroleum, Changping District, Beijing City, 102249, China;
2. State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Changping District, Beijing City, 102249, China;
3. School of Ocean Sciences, China University of Geosciences, Beijing City, 100083, China
Abstract：The Triassic middle oil-member is the most important production pay zone in Akeyasu Area,however its sandbody type and its distribution characteristics have not been clearly understood. In high precision chorostratigraphy framework which was developed in LST4-TST4 of sequence SQ4 in middle oil-member sandbodies,by integrating logging data with grain size analysis 6 subfacies including braided river delta front,sublacustrine inner fan,middle fan,outer fan and shore-shallow lake,semi deep lake-deep lake,and 9 microfacies were recognized,it is revealed that the main types of the middle oil-member major sandbodies are underwater distributary channel,supply water channel,braid canal and slump fan sandbody. By integrating seismic facies analysis with some technical means,such as Stratimagic waveform seismic facies analysis,seismic spectral decomposition,seismic amplitude attribute analysis and impedance inversion,the distribution of LST4 major sandbody was predicted and its sediment microfacies type and distribution were determined,based on sandbody distribution which was revealed by impedance inversion and top structural feature of the LST4 major sandbody,two favorite targets which are sublacustrine fan middle fan faulted anticline trap located in the east of Th2 well and sublacustrine fan middle fan braid canal lithologic trap located in the south of Kz2 well were optimized.
