万昌地区永二段水下滑塌扇内上倾尖灭砂体识别

上倾尖灭型油气藏是岩性油气藏的基本类型之一.对上倾尖灭砂体的识别是岩性油气藏勘探的任务之一.在对比单一利用地震资料、地震属性和波阻抗反演等方法进行砂体识别的优缺点后, 提出运用波阻抗和瞬时相位相叠合的新方法对砂体进行识别.运用此方法, 对万昌地区水下滑塌扇内部上倾尖灭砂体进行了精细解释和分析.得出以下结论: (1)通过钻井岩心识别沉积相类型, 结合均方根振幅属性和同沉积断层分布情况, 可以准确地确定伊通盆地万昌地区永二段水下滑塌扇的分布范围; (2)用波阻抗和瞬时相位属性联合的方法对水下滑塌扇内部上倾尖灭砂体进行识别取得了较好的效果, 万昌地区WC1井附近水下滑塌扇内至少有两期最具油气勘探价值的上倾尖灭砂体. 

Identifying Updip Pinch-Out Sandstone in Subaqueous Slump Fans of Yonger Member Using Acoustic Impedance and Instantaneous Phase in Wanchang Area, Yitong Basin

Updip pinch-out reservoir is one of the lithologic reservoirs. Identifying updip pinch-out reservoir is a major task of lithological reservoir exploration. In this study, analysis of the 3D seismic reflection, instantaneous phase and acoustic impedance is conducted to identify and interpret the sandstone. It is found that the combined data of acoustic impedance and the instantaneous phase has better detectability and is more reliable indicator of the sandstone distribution than any of these individual seismic data including the 3D seismic reflection, instantaneous phase and acoustic impedance.In Wanchang area, combined analysis of the acoustic impedance and instantaneous phase in the subaqueous slump fans is a valid approach for identifying and interpreting the updip pinch-out sandstone. Two major findings are as follows: (1) Combined analysis of the cores, seismic attribution and the distribution of the synsedimentary faults could exactly identify the distribution of the subaqueous slump fans in the Wanchang area. (2) After identifying updip pinch-out sandstone in subaqueous slump fans using acoustic impedance and the instantaneous phase in the Wanchang area, there are at least two stages updip pinch-out sandstone near well WC1 in subaqueous slump fans which are most potential in Wanchang area.