莺歌海盆地斜坡带全井段孔隙压力预测方法

为探索多源多机制孔隙压力预测方法，精准预测莺歌海盆地斜坡带全井段的孔隙压力，综合考虑区域沉积构造演化过程、测井数据的响应特征，明确了各层段异常高压成因；针对常规高压机制地层，优选了不同层段的孔隙压力预测模型；对复杂成因地层开展了孔隙压力精确预测新方法的研究。研究表明，莺一段—莺二段上部层段异常高压成因为 “欠压实作用”，可使用Eaton法预测孔隙压力；莺二段下部层段异常高压成因为 “欠压实作用为主、流体膨胀为辅”，可利用Bowers加载法预测孔隙压力；黄一段异常高压成因为 “流体膨胀为主、欠压实作用为辅”，可使用Bowers卸载法预测孔隙压力；黄二段异常高压成因复杂，为“超压传递+流体膨胀为主、欠压实作用为辅”的组合模式，针对此特殊成因，提出了多变量孔隙压力预测新模型。将预测结果与实测孔隙压力数据进行了对比，全井段预测精度达97%，能满足工程需求。研究结果可为莺歌海盆地斜坡带钻井设计和施工提供依据和指导。

Method for predicting pore pressure of whole well interval in slope zone in Yinggehai Basin

In order to explore the method for predicting pore pressure with multiple sources and multiple mechanisms, and to accurately predict the pore pressure of the whole well interval in the slope zone of the Yinggehai Basin, by comprehensively considering the evolution process of regional sedimentary structure and the response characteristics of logging data, the cause of abnormally high pressure in each interval was clarified. For formations with conventional high-pressure mechanisms, the models for predicting pore pressure in different intervals were optimally screened. For formations with complex genesis, a new method for accurately predicting pore pressure was studied. The research shows that the abnormally high pressure in the upper intervals of the Ying 1-Ying 2 member is caused by under-compaction, where the pore pressure can be predicted by the Eaton method. The cause of the abnormal high pressure in the lower intervals of the Ying 2 member is that, under-compaction primarily, supplemented with fluid expansion, where the pore pressure can be predicted with the Bowers loading method. The cause of the abnormal high pressure in the Huang 1 member is that, fluid expansion primarily and supplemented with under compaction, where the pore pressure can be predicted with the Bowers unloading method. The causes of the abnormal high pressure in the Huang 2 member are complex, which is a combined pattern composed of overpressure transmission+fluid expansion primarily, supplemented with under compaction, and aiming at this special cause, a new multivariable pore pressure prediction model was proposed. Comparing the prediction results with the measured pore pressure data, the prediction accuracy of the whole well interval is up to 97%, which can meet the engineering requirements. The research results can provide a basis and guidance for drilling design and construction in the slope zone of Yinggehai Basin.