钻井液侵入情况下随钻电磁波电阻率测井的响应

Logging responses of electromagnetic wave resistivity while drilling with drilling fluid intrusion

李亨 刘迪仁 倪小威 冯加明 杨勇 杨多 2

长江大学油气资源与勘探技术教育部重点实验室，湖北 武汉 430100 长江大学地球物理与石油资源学院，湖北 武汉 430100）

MOE Key Laboratory of Exploration Technologies for Oil and Gas Resources, Yangtze University, Wuhan 430100, China School of Geophysics and Oil Resources, Yangtze University, Wuhan 430100, China)

钻井液侵入地层使得井周介质电阻率分布发生变化，从而影响了随钻电磁波电阻率测井的响应。文中基于渗流理论、对流扩散理论及电磁场理论，利用有限元数值模拟技术，定量分析了侵入时间、储层孔隙度等变化对钻井液侵入下随钻电磁波电阻率测井响应的影响。结果表明：钻井液侵入10 min后，随钻电磁波电阻率测井的响应明显受到钻井液侵入的影响；储层孔隙度大于15%时，相位差响应增长超过5%；储层含水饱和度小于60%时，相位差响应增长超过4%；钻井液与地层水的矿化度比值大于0.244时，相位差响应增长超过10%；储层渗透率和压差变化在钻井液侵入情况下对随钻电磁波电阻率测井相位差响应的影响基本固定。研究结果为随钻电磁波电阻率测井解释消除钻井液侵入的影响提供了一定理论基础，对探测深度的综合判断有助于相关仪器的研发和改进。

Mud?鄄filtrate intrusion into the formation changes the resistivity distribution of the wellbore medium, which has a certain impact on electromagnetic wave resistivity logging while drilling. Based on the seepage theory, convection diffusion theory and electromagnetic field theory, this paper quantitatively analyzes the impact of the intrusion time, reservoir porosity and other changes on the electromagnetic wave resistivity logging responses while drilling under dynamic drilling fluid intrusion by finite element method. According to the research results, after 10 min of mud intrusion, the electromagnetic wave resistivity logging while drilling is obviously affected by mud intrusion, and when the porosity of the reservoir is greater than 15%, the phase difference response of the electromagnetic wave resistivity while drilling increases by more than 5%; when the saturation is less than 60%, the phase difference response of the electromagnetic wave resistivity while drilling increases by more than 4%; the difference of mineralization (the ratio of mud salinity to formation water salinity) is greater than 0.244, the phase difference response of the electromagnetic wave resistivity while drilling increases by more than 10%; the influence of differential pressure change and permeability change on the phase difference responses of the electromagnetic wave resistivity while drilling under the condition of drilling fluid intrusion is basically fixed. The research results provide a theoretical basis for the elimination of mud intrusion during the interpretation of electromagnetic wave resistivity logging while drilling, and the comprehensive judgment of the depth of detection contributes to the development and improvement of related instruments.

10.6056/dkyqt201905028