薄互层水平井测井电阻率的各向异性校正

Anisotropic Correction for Resistivity Logging of Horizontal Well in Thin Interlayer Reservoir

对薄互层水平井测井电阻率进行各向异性校正。首先依据水平井测井参数对井轨穿层特征作出判断,通过在穿层界面位置设置虚拟直井提高三维地层插值建模的精度,确定水平井井眼轨迹在三维空间上与目标地层的相互位置关系。然后,针对砂-泥岩薄互层提出"相对电阻率各向异性"的概念,获得水平井周围目标地层受三维地质模型约束的相对电阻率各向异性系数数据体。最后,结合地层与井轨的夹角,计算得到可以代表目标地层真实电阻率的水平电阻率。该方法成功应用于肇州油田某区块水平井,校正后的水平井测井电阻率能够更好的反映储层岩性特征,并能够真实的反映储层含油性特征,提高了储层评价的准确度和可靠性。

In order to correct the anisotropic resistivity for horizontal well logging in thin interlayer oil reservoir, firstly the crossing points of the horizontal well track with target formations were determined by analyzing the response characteristics of logging parameters, and a series of virtual vertical wells at these locations were set to get an accurate 3D lithology model adapting the horizontal well track survey. Secondly, a 3D relative resistivity anisotropic coefficient volume was calculated based on the deep resistivity measured from neigbbouring vertical control wells for target formations. Finally, the horizontal resistivity logging for varying angles between the well track and formation beddings was calculated. This method was successfully applied to horizontal wells of Zhaozhou oil field and the corrected resistivity showed improved responses on lithology and pore fluid. Thus, it would increase both accuracy and reliability of the reservoir evaluation for horizontal wells.