波形指示反演在灰质发育区薄互层浊积岩预测中的应用——以牛庄洼陷沙三中亚段为例

The application of waveform inversion prediction of thin turbidite reservoir to calcareous depositional area:A case study of E3s3^2 in Niuzhuang sag

在高勘探程度阶段,牛庄洼陷沙三中亚段浊积岩油藏主要勘探对象是“个体小、薄互层、橫变快、含灰质”的复杂隐蔽储层。针对薄互层砂体地震难分辨、灰质泥岩背景下砂岩难识别两大难题,开展了岩性敏感曲线重构和波形指示反演相结合的砂体预测研究。结果表明:波形指示反演明显压制了灰质泥岩对砂体预测的干扰,利用波形横向变化代替传统变差函数进行高频成分模拟,提高了反演精度,5 m以上储层预测结果与实钻井吻合度为88.5%,2~5 m储层预测吻合度达到80.5%。反演砂体分布符合研究区沉积演化规律及油藏流体分布认识。利用反演结果指导牛庄洼陷滚动探井和开发井部署,在5个开发区共部署滚动探井和开发井20口,其中8口井完钻投产后获得工业油流,预计新建产能4×10^4 t。

In the high exploration stage,the exploration target of the turbidite reservoirs of E3s3^2 in Niuzhuang sag has been gradually turned to complex subtle reservoir whose characteristics are small scale,thin thickness,rapid lateral variation and containing carbonate.It is difficult to describe the thin interbed reservoir using conventional seismic data,and is also difficult to identify sandstone in gray background.To tackle these problems,the authors studied the prediction of sand reservoir by combining the reconstruction of lithologic sensitive curve with the inversion of waveform indication.It turns out that seismic indication inversion obviously suppresses the interference of gray matter components,and the inversion using lateral variation of waveform instead of traditional variation function can improve the inversion accuracy,with the accuracy of thickness above 5 m being 88.5%,and that of thickness of 2~5 m being 80.2%.The inversion of sand conforms to the sedimentary law and the reservoir fluid distribution in the study area.By applying the reservoir prediction results,a total of 20 exploration wells were deployed in 5 development blocks,of which 8 wells were drilled and industrial oil was obtained after they were put into production,with the new expected capacity being about 4×10^4 t.