基于非线性反演的井壁稳定随钻预测方法  

Predicting borehole stability while drilling based on nonlinear inversion

作　　者：吴超[1] 刘建华[1] 张东清[1] 王磊[1] 

机构地区：[1]中国石油化工股份有限公司石油工程技术研究院,北京100101

出　　处：《岩土工程学报》2015年第10期1810-1817,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家科技重大专项专题项目(2011ZX05005-006-001)

摘　　要：常规井壁稳定预测方法计算量大、操作繁琐、适用范围有限,严重影响其实钻应用效果。通过考察声波速度、地震记录及井壁稳定参数之间的定量关系,建立起利用地震资料直接反演孔隙压力、地应力、岩石强度的模型。根据反演模型的非线性特征,结合井壁稳定参数的地质统计特性,运用随机地震反演方法预测待钻地层的孔隙压力、地应力、岩石强度,并根据反演结果进一步预测井壁稳定性。在实钻过程中,利用录井资料的实时分析和井壁稳定参数的分层地质统计模型,对钻头前方地层的井壁稳定性进行随钻预测。在川东北元坝气田的应用情况表明,本方法的综合性能相比常规方法有明显提高,具有较强的随钻预测能力。The conventional borehole stability prediction methods are characterized by a large amount of calculation, complex operation and limited applicability, which can seriously affect real time application of the technology. Through intensive studies on the quantitative relationships between acoustic velocity, seismic data and borehole stability parameters, the direct seismic inversion model for pore pressure, in-situ stress and rock strength is established. Based on the nonlinear characteristics of the inversion model as well as the geological statistics features of borehole stability parameters, pore pressure, in-situ stress and rock strength of the formation to be drilled can be predicted by employing the stochastic inversion method so as to further forecast borehole stability. In actual drilling, the real-time geological logging data and layered statistical mode of borehole stability parameters can be used to predict borehole stability of the formation ahead of bit while drilling. The practical application of the proposed method in Yuanba Gas Field of Northeast Sichuan shows that the proposed method possesses strong ability of prediction while drilling and its comprehensive performance is significantly improved compared with the conventional methods.

关 键 词：井壁稳定 随钻预测 地震资料 非线性 随机反演 

分 类 号：TU43[建筑科学—岩土工程]