苏里格气田致密砂岩气藏储层表征技术及其发展展望

Characterization technology for tight sandstone gas reservoirs in the Sulige Gas Field,Ordos Basin,and its development prospect

储层表征与建模是油气田开发领域的一项关键技术,致密砂岩气藏因其特殊性,储层表征技术仍处于探索阶段。鄂尔多斯盆地苏里格气田主力产气层下二叠统石盒子组8段由多期河道砂体叠置而成,具有低孔隙度、低渗透率、强非均质性的地质特征,随着水平井的规模开发,更加精细的储层表征就显得尤为重要。为此,在借鉴油藏表征技术的基础上,结合苏里格气田致密砂岩气藏的地质特点及多年的开发实践,提出了该气田储层表征的技术思路:①精细地层划分对比,建立等时地层格架;②以刻画砂体、有效砂体为重点,建立储层地质知识库;③优化三维地质建模方法,建立精细地质模型。根据苏6区块历年地质建模效果和当前国内外河流相储层的地质建模方法,总结归纳出了不同开发阶段、含不同生产资料的相控建模技术。最后结合气田开发实际,展望了致密砂岩气藏储层表征技术的主要发展方向。

Reservoir characterization and modeling is a key technology in the field of oil and gas development. For tight sandstone gas reservoirs, reservoir characterization technology is still at exploratory stage. In the Sulige Gas Field, Ordos Basin, the principal gas producing layer is the 8th Member of the Shihezi Formation, Lower Permian, which is composed of multiphase channel sand bodies in the form of superimposition. It is geologically characterized by low porosity, low permeability and strong heterogeneity. With the scale development of horizontal wells, more accurate reservoir characterization is particularly important. In reference to oil reservoir characterization technologies, a technical idea of reservoir characterization for the Sulige Gas Field was proposed based on an analysis of the geologic characteristics of tight sandstone gas reservoirs and years＇ development practice. First, isochronal stratigraphic frame- work was established to conduct fine stratigraphic classification and correlation. Second, reservoir geologic database was set up to characterize sandbodies and especially effective sandbodies. And third, the 3D geologic modeling method was optimized to establish a fine geologic model. Based on current geologic modeling methods for fluvial reservoirs, facies-controlled modeling technologies for different development stages and different production data were summarized after geologic modeling results of Block Su 6 over the years were analyzed. Finally, the main development direction of reservoir characterization technologies for tight sandstone gas reser- voirs was forecasted according to the practical development situations of the Sulige Gas Field.