文昌A凹陷某气藏地震非弹性效应与含气性预测

Seismic nonelastic effect and about gas-bearing prediction of a certain gas reservoir in the A sag of Wenchang area

在对文昌A凹陷内隐蔽油气藏勘探的尝试中,钻井成功率并不高,主要原因在于灰质含量较高的珠二段1砂组影响了下伏2砂组地球物理特性的表征。面对这种岩性组合,AVO方法缺乏相应的地球物理特征响应,而地震非弹性效应预测技术利用在油气藏范围内地震吸收衰减率上升段与速度弥散性异常共存的现象却能获得很好的含气异常响应。钻井结果和中途测试结果证实,地震非弹性效应预测结果完全符合地下储层含气性实际情况。

In the trial exploration of subtle reservoir in A sag of Wen-chang area, the success ratio of drilling is not ideal. The main reason is that the first sand set of Zhu2 segment with high carbonate content affects the description of geophysical characteristics in the second sand set. The AVO has few responding geophysical features for this lithological association. However, the seismic non-elastic effect prediction can obtain good gas-bearing unusual response by using the abnormally coexisting phenomenon of ascending passage of seismic absorption attenuation rate and the dispersion of velocities. The drilling results and drill-stem test results prove that the prediction results of seismic nonelastic effect completely coincide with the actual gas-bearing situation in the reservoir.