摘要
The Jurassic Lianggaoshan Formation in eastern Sichuan Basin is a key target for shale oil exploration.It faces challenges in three-pressure prediction due to complex structural and sedimentary interactions,as well as strong reservoir anisotropy.These issues often lead to wellbore instability and gas logging anomalies during drilling.This study presents an integrated workflow that combines residual moveout correction using correlation-based dynamic time warping(CDTW),high-resolution seismic waveform indication inversion,and three-pressure prediction of jointing well-seismic data.Applied to the LT1 well block,the workflow effectively corrects anisotropic residual moveout in image gathers,leading to a signal strength increase of over 10%in frequency bands above 30 Hz and enhancing event continuity.High-resolution rock mechanical parameters are obtained through seismic waveform inversion and regional calibration,enabling the prediction of three-dimensional pore pressure,collapse pressure and fracture pressure.The results are consistent with actual drilling gas shows and core data,confirming the method's accuracy and supporting mud weight planning and wellbore stability efforts.This cost-effective and technically robust approach proves highly reliable in complex environments with significant heterogeneity and anisotropy,assisting drilling decisions and risk management in eastern Sichuan and similar challenging geological settings.
四川盆地东部侏罗系凉高山组是页岩油勘探的重要目标层系。该区域受复杂构造与沉积耦合作用及强烈储层各向异性的影响,面临地层三压力预测的挑战,钻井过程中常出现井壁失稳和气测异常等问题。本研究基于互相关动态时间规整的剩余时差校正与高分辨率地震波形指示反演,提出了一套井震联合三压力预测综合技术流程。在LT1井区应用中,该流程有效校正了成像道集中的各向异性剩余时差,使30 Hz以上频带信号能量提升超10%,并增强了同相轴连续性。通过地震波形指示反演与区域标定,获得了高分辨率岩石力学参数,实现了三维孔隙压力、坍塌压力和破裂压力的预测。预测结果与实际钻井气测显示及岩心资料吻合,验证了方法的准确性,为钻井液密度设计和井壁稳定性控制提供了依据。本方法在强非均质性与各向异性并存的复杂地质环境中展现出高度可靠性,可为四川盆地东部及类似复杂地质条件下的钻井决策与风险管理提供技术支持。
基金
supported by Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(No.2020CX010202).
