水平井地震地质导向技术及其在涪陵页岩气田的应用

Seismic geo-steering technology of horizontal well and its application in Fuling shale gas field

涪陵页岩气田晚奥陶世五峰组—早志留世龙马溪组(O3w-S1l)页岩气层经过多期构造运动改造,地层变形强烈,断裂、褶皱发育,地层产状变化剧烈,给页岩气水平井导向带来了极大挑战。为保证水平井轨迹在优质页岩气层中穿行,提出了基于导向模型实时修正的水平井地震地质导向技术。在区域地质特征研究的基础上,以地震剖面为初始导向模型,综合钻井、录井、测井等多种数据信息,开展标志层特征分析、实时小层精细对比和速度场实时更新,建立了靶点深度和地层产状的预测方法,保证了精准入靶,形成了水平井井眼轨迹实时跟踪调整技术,确保了水平井井眼轨迹在优质页岩气层中穿行。实践证明,水平井地震地质导向技术有效指导了水平井钻井,为涪陵页岩气田的高效开发提供了技术保障。

Owing to multistage tectonic movements, shale gas reservoir O3W-S1l in the Fuling shale gas field has been highly deformed, and fractures and folds have developed. The seismic geo-steering drilling technology for horizontal wells encounters challenges owing to substantial change in the occurrence of this formation. To increase the rate at which high-quality shale formations are encountered during drilling, the seismic geo-steering drilling technology for horizontal wells based on a real-time correction model is presented. First ,based on regional geological feature analysis, characteristics of the guiding bed were analyzed,and a real-time fine substratum correlation was conducted. Second,by taking the seismic section as the initial geo-steering model,with comprehensive use of drilling and well logging, the velocity field was updated in real time. Then, the target depth and formation occurence were predicted, and a real-time trajectory tracking and adjustment technique for horizontal wells was established, ensuring the trajectory of horizontal wells passing through high-quality shale gas reservoirs. The practice indicated that the seismic geosteering technology guided the drilling of horizontal wells in the Fuling shale gas field effectively.