塔河油田于奇东地区隐蔽油气藏预测方法及应用研究

Prediction Method and Application of Subtle Reservoirs in the East of Yuqi Area of Tahe Oilfield

隐蔽油气藏勘探仍然是一大难点,存在圈闭识别难度大、钻前预测可靠性低等一系列问题。该文以塔河油田于奇东三维地震和3口气井、6口非含气井资料为基础,通过地震波衰减异常处理技术和成藏条件分析方法,探讨了奥陶系碳酸盐气层的地震波衰减响应特征,同时用该方法预测了可能存在的东河砂岩碎屑岩隐蔽圈闭油气藏。研究结果表明,衰减含气检测对于碳酸盐溶洞、裂缝—溶洞型储层具有一定的指示效果,而对于以裂缝为主的储层应用效果不理想。通过目的层的衰减异常分析及沉积相和构造综合研究,在该区识别出一个东河砂岩储层的断裂—地层复合圈闭可能油气藏,其面积约为30.53 km 2,闭合高度为120 m,气层最厚可达51 m。衰减含气检测在隐蔽油气藏勘探中具有较大的应用潜力。

The exploration of subtle reservoirs is very difficult but great potential.Based on post-stack seismic data and nine well data in east of Yuqi 3-D seismic survey in Tahe field,the seismic wave attenuation and geological trap conditions analysis are combined to detect known gas pools and attempt to find new gas trap.It is found that the karst gas reservoirs of Ordovician Yijianfang and formation limestone have impressive response of seismic attenuation,but no attenuation display for fracture limestone gas reservoirs.Using the same attenuation gas detection technique,we have found a possible gas trap of Donghe sandstone in the west of the study area.It belongs to a structural-stratigraphic composite trap bounded by faults and the sandstone pinch out line on the unconformity surface,with an area 30.53 km 2,the closure height 120 m,and the gas layer about 51 m.Studies have shown that attenuated gas detection has great potential for application to subtle reservoir exploration.