姬塬地区延安组基于水性分析的油水识别方法

Oil Water Identification Method Based on Water Analysis for Yanan Formation in Jiyuan Area

常规测井解释方法以岩石物理实验、测井数据为依据,综合考虑了储层岩性、物性、流体对电阻率的影响,忽略了地层水矿化度。在一些地层水水性变化复杂的地层,水性的变化会消弱甚至抵消含油性对电阻率的影响,这使得应用常规测井解释方法进行油水判识困难。姬塬地区延安组地层受地层水性影响,油层测井响应特征与水层差异小,油水层识别困难。通过研究地层水水型、矿化度及其与测井资料的对应关系,建立了基于区域水性特征的油水识别方法,分水型给出了姬塬地区延安组地层的出油下限,提高了油水判识精度,取得了较好的地质效果。

The conventional logging interpretation method is based on rock physical experiments and logging data,and comprehensively considers the effects of lithology,physical property and fluids on resistivity without considering salinity of formation water.However,in some stratums with complex water changes,such as Yanan formation in Jiyuan area,the changes of water will weaken or even offset the resistivity effect of oiliness,thus leads to complex logging responses.The low contrasts of the oil and water layer characteristics bring about difficult evaluation of these reservoirs with the conventional logging interpretation methods.In order to better identify oil and water layers,a new area-water-analysisbased oil and water layer identification method is established via analyzing the corresponding relationship among the hydrochemical type and salinity of formation water as well as the logging data.The method identifies the lower limit of oil reservoir and improves oil and water layer identification accuracy of Yanan formation in Jiyuan area,attaining agood geological effect.