碳酸盐岩溶洞型储层综合识别及预测方法

多期岩溶作用使碳酸盐岩溶洞型储层各向异性特征显著。由于溶洞被少量充填、大部分充填或完全充填,使溶洞储层的地球物理特性变得更为复杂,单因素的地质或地球物理分析方法导致溶洞储层的钻井成功率较低。对塔河油田11区的综合研究表明,碳酸盐岩有效溶洞储层的发育应同时具备3个常规地震剖面波形特征,即断裂+串珠状反射+强波谷;一间房组顶面0~20ms振幅变化率特征为较强—极强;波阻抗特征为极低的波阻抗值(绝对波阻抗值小于1.2×10⁷kg/m³)。利用这3个条件可识别和预测有效溶洞和被完全充填的非储层溶洞,有效实现了碳酸盐岩溶洞型油藏的滚动开发。

Integrative identification and prediction methods for carbonate rock cave reservoir

The anisotropic characteristics of carbonate rock cave reservoirs were distinguished by multi phase karstification. The geophysical characteristics of cave reservoirs became more complex since different caves have different filling pattern with a little filled, mostly filled or full filled packs. The single factor analysis of the geological or geophysical method would lead to less success in well drilling. The integrative study on Block 11 of Tahe Oilfield shows that the generation of carbonate cave reservoirs needs to have three conventional seismic section waveform characteristics as “fracturing, reflect with a string of beads and strong wave trough”. The variation ratio of seismic amplitude was obviously shown as very strong at the top of Yijanfang Group within 0～20 ms, and the absoluteness value of impedance was below 1.2×10⁷kg/m³. So the available cave and full filled cave can be respectively identified and predicted by above three conditions. This method was proved by reservoir development practice in the cave carbonate pools of Tahe Oilfield. 