过井眼缝洞地层双侧向电阻率测井敏感性因素分析

The Analysis on Sensitivity of Dual Lateral Resistivity Logging for Fracture-cavernous Formation through the Wellbore

为了更好地识别和评价碳酸盐缝、洞,建立了碳酸盐岩缝-洞识别室内物理模拟试验装置及双侧向电阻率测井试验方法。通过建立的试验装置,进行了缩小比例的双侧向电阻率测井物理模拟试验,评价了不同尺寸泥浆充填洞穴、不同充填物洞穴、不同充填物程度洞穴对双侧向电阻率测井的影响。结果表明:不同泥浆充填时,深、浅侧向电阻率均随洞穴模型直径的增加而减小,且深、浅侧向电阻率出现正差异,先增大后减小,最后趋于相同;当不同充填物洞穴模型的双侧向电阻率与基岩电阻率相当且异常幅度差较小时,则将洞穴模型判定为碳酸盐岩溶蚀物充填类型;从不同充填物程度对双侧向电阻率测井的影响来看,高填充物的浅侧向电阻率能够较好地反映真实电阻率信息。该研究成果为缝洞储层的双侧向电阻率测井识别与评价提供了有利的方法。

In order to recognize and evaluate carbonate fractures and caves,aphysical simulation device and the dual laterolog method were established in laboratory.Through the established experiment device,scale reduced physical simulation experiments of the dual lateral resistivity logging were carried out,and the effects of different size mud-filling carves,caves with different filling materials and filling degrees on the dual lateral resistivity logging were evaluated.The results indicate that when filling with different muds,deep and short resistivity decrease with the increase of cave model diameter,and the positive difference is induced in deep and short resistivity,which increases first and then decrease,eventually is in similar level.While the dual laterolog response resistivity of fracture-cave model with different fillings is equivalent with basement rock resistivity and the abnormal magnitude difference is relatively small,the cave model is determined as the filling type of carbonate rock solution.In consideration of the impact of different filling degrees on the dual laterolog,the short resistivity of high fillings can better reflect the true resistivity.The research provides a favourable method for recognizing and evaluating the cave-fractured reservoirs using the dual laterolog method.