Sedimentary facies and reservoir prediction of the Lower Jurassic Da'anzhai Member,Longgang area,central Sichuan Basin
Du Jiangmin1,2, Zhang Xiaoli1, Zhang Fan3, Wang Xingzhi3, Feng Mingyou3, Luo Chuanyou4, Nie Wancai4
1 State Key Laboratory of Continental Dynamics/Department of Geology,Northwest University,Xi'an 710069,Shaanxi
2 College of Resources,Shijiazhuang University of Economics,Shijiazhuang 050031,Hebei
3 School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,Sichuan
4 Changqing Oilfield Company,PetroChina,Xi'an 710018,Shaanxi
Based on integrated application of drilling,logging and seismic data,the types of sedimentary facies and their distribution in Da'anzhai Member in Longgang area were studied. The lacustrine sediments of Da'anzhai Member were divided into 4 subfacies and several microfacies. Sedimentary distribution and evolution in the study area were mainly affected by lake-level fluctuation during the Da'anzhai period,experiencing a large-scale water transgression and regression. During the period of the third submember of Da'anzhai,water transgression occurred,the deposits were mainly shallow and semi-deep lacustrine. During the period of the first-third submember of Da'anzhai,the water was the deepest,the deposits were mainly of semi-deep lacustrine. Then,water regression occurred,lake-level dropped to a very low stand,the deposits were mainly shore-shallow lacustrine. Sedimentary facies distributed obviously in a ring shape on the plane,whereby the sedimentary facies model of Da'anzhai Member were established. There were mainly five shelly shoals in the first submember of Da'anzhai,which were the most conducive to the formation of reservoirs. The main types of reservoir rocks were shelly limestone and argillaceous shelly limestone. Combined with fracture analysis,three favorable reservoir zones were predicted.
Du Jiangmin,Zhang Xiaoli,Zhang Fan et al. Sedimentary facies and reservoir prediction of the Lower Jurassic Da'anzhai Member,Longgang area,central Sichuan Basin[J]. JOPC, 2015, 17(4): 493-502.
