利用常规测井资料识别致密砂岩气层

Identification of Tight Sandstone Gas Reservoirs by Using Conventional Well Logging Data

致密砂岩气层表现出明显的低孔隙度、特低渗透率及复杂的孔隙结构特征,给测井储层评价带来了巨大的挑战。选定鄂尔多斯盆地某区的致密砂岩气层为研究对象,根据储层的"四性"关系分析,以常规测井资料为基础,辅以自然伽马能谱测井资料进行研究。首先,利用自然伽马能谱测井准确求取储层的泥质含量;然后,根据密度测井计算储层孔隙度,并结合孔隙度和泥质含量预测储层的渗透率;最后,基于Archie公式,计算含气饱和度,建立研究区气层识别图版,以此为基础识别致密砂岩气层。

Tight sandstone gas reservoirs always show the properties of low porosity,extra low permeability and complicated pore structure,which bring a great challenge to the reservoir evaluation. In this paper,taking the tight sandstone gas reservoir in a block of Ordos basin as research object,according to the analysis of four-property relationship in the reservoir,based on the conventional logging data and natural gamma ray spectrometry logging data,the shale content in the reservoir was determined by GR logging,and then the porosity was calculated based on density logging,and the permeability of the reservoir was predicted based obtained shale content and porosity. At last,based on Archie formula,the gas saturation was calculated so as to establish the gas identification chart in the study area,and this chart was applied to distinguish the tight sandstone gas reservoir.