川中龙女寺地区雷一1亚段构造解释方法

中三叠统雷口坡组雷一¹亚段是四川盆地中部地区的主要产层段之一，该层段之上、下地层均发育有塑性软地层（膏盐层）。由于塑性地层在受力形变过程中表现为较强的流动性，造成附近的刚性地层受力复杂，使雷一¹亚段在地震剖面上表现为紧密的背斜褶皱。雷一1亚段与围岩的波阻抗差较小，反射能量较弱，加上自身及围岩横向岩性变化，加强了雷一¹亚段反射能量的不稳定性。这些因素增加了地震剖面对比追踪的难度，一直是川中地区地震资料解释的难点之一。以川中龙女寺构造为例，在三维叠前时间偏移的基础上，认真分析、利用钻井资料，精细标定地质层位，综合多种方法对比追踪，改进时深转换速度模型精度设计方法，使雷一¹亚段构造图反映的地质细节更为丰富、可靠，效果较好。

The interpretation method of Lei-11 structure in Longnushi area in central Si-chuan basin

The middle Triassic Leikoupo formation Lei 11 is one of the important reservoirs in central Sichuan basin. The plastic soft formations (gypsum salt bed) are developed both in the overlying formations and the underlying formations. When the plastic formation is forced to deform, the fluidity is very strong, and this makes the force in inflexible formation complex. So Lei 11 was seriously folded, and in seismic cross section it is a close anticlinal fold. For the difference between Lei 11 sub section wave impedance and surrounding rock wave impedance is small, the reflected energy is relatively poor, and the horizontal lithology changes in it and the surrounding rock, the instability of Lei 11 reflected energy is badly increased. All the factors make the correlation of the seismic cross section difficult to track, and this is always one of the difficulties in interpreting and doing correlation of the seismic data in central Sichuan basin. Take the structure of Longnushi as an example, based on the 3D prestack time migration, this study analyzed carefully using well drilling data, and demarcated geologic horizon exactly and in detail. Combined various methods to compare and track, we improve the accuracy design method of the time depth conversion velocity model, and thus the geologic details that the structural maps reflect results are more abundant, reliable and effective.