Sedimentary Characteristics and Developing Conditions of Gravity Flow-Genetic Reservoirs in Ramp Margins of Depression-Lacustrine Basin——An example from Wellblock Shinan-31 in hinterland of Junggar basin

Shinan-31 Wellblock is a large lithologic oil-gas reservoir discovered in Shinan area in hinterland of Junggar basin in recent years.Its petroliferous strata around the ramp margins of depression-lacustrine basin belong to the K1q11 sand layer of Qingshuihe formation of Cretaceous.But there has been controversial on the sedimentary facies type of the reservoir.The core observation and seismic information analysis suggest that in Shinan-31 Wellblock possesses the necessary conditions for forming gravity flow sediments.It is concluded that in the conditions of valley,terrace and plentiful mass supplementation,gravity flow sediments can develop in the depression-lacustrine basin.