针对钻井液侵入过程中储层径向电阻率可能存在的高侵、低侵、低阻环等非线性变化特征,提出五参数地层模型。基于几何因子理论,采用阻尼最小二乘法,利用阵列感应测井资料对地层参数进行反演,并重构储层径向电阻率剖面。结果表明:五参数模型能很好地表征不同侵入特征的储层电阻率分布形态;基于0.6m分辨率阵列感应测井曲线进行反演,在层厚大于0.5m的砂泥岩储层中,可较好地重构储层电阻率剖面,获取原状地层电阻率;反演算洪稳帘可靠一能对实际测井资料进行连续快速处理,为储层流体识别提供依据。
In view of the nonlinear resistivity radial distribution characteristics including resistive invasion, conductive invasion and resistivity distribution with low resistivity annulus during drilling fluid invasion, five-parameter model was proposed. On the basis of geometrical factor theory, damped least square method was adopted to realize formation pararneters inversion with array induction logging data, and formation resistivity distribution was reconstructed. The results show that five-parameter model can well describe resistivity distributions of different invasion characteristics. For sand-shale reservoir whose layer thickness is grea- ter than O. 5 m, the inversion of array induction logging curve with the resolution of O. 6 m can well reconstruct reservoir resis- tivity profile and original formation resistivity can be obtained. The inversion algorithm is stable and reliable, which can process well logging data fast and continuously and can provide help for reservoir fluid property identification.