粗粒非均质油藏流动单元划分及测井物性模型——以达尔其油田腾下段储层为例

Flow unit division and logging physical property model for coarse-grained heterogeneous oil reservoirs:Taking the lower Tengger formation reservoir in Daerqi Oilfield as an example

达尔其油田腾下段储层属于陡地形、近物源背景下快速堆积的粗粒碎屑沉积,具有岩性复杂、非均质性强等特点,用常规方法建立的测井物性模型误差较大,难以满足储层精细评价的要求。储层流动单元法将内部相对均质的储层分为一类,在此约束下分类建立的物性模型可提高测井模型的解释精度。利用储层镜下薄片、物性、压汞、测井等资料,在分析储层特征的基础上,划分储层流动单元并建立测井物性模型。基于实测岩心物性资料,采用地层流动带指数法和模糊聚类的方法进行储层流动单元划分,将腾下段储层划分为4类,各类储层具有相似的孔隙结构和渗流特征,腾下段主要发育Ⅲ、Ⅳ类储层,以席状砂、远砂坝微相及滨浅湖亚相为主。依据流动单元分类结果建立了储层的测井物性模型,通过单井验证符合度高,模型具有一定的区域适用性,可信度较高。形成基于流动单元分类的复杂粗粒砂岩储层物性解释技术,能有效指导该类储层物性预测。

The lower Tengger formation reservoir in Daerqi Oilfield belongs to coarse-grained clastic deposits rapidly accumulated in steep terrain and near provenance background.It has the characteristics of complex lithology and strong heterogeneity.The logging physical property model established by conventional methods has large error and is difficult to meet the requirements of fine reservoir evaluation.The reservoir flow unit method divides the relatively homogeneous reservoirs into a class.Under this constraint,the physical property model established by classification can improve the interpretation accuracy of the logging model.Based on the analysis of reservoir characteristics,the reservoir flow unit was divided and the logging physical property model was established by using the data of thin section,physical property,mercury injection and logging under the reservoir microscope.Based on the measured core physical property data,the formation flow zone index method and fuzzy clustering method were used to divide the reservoir flow units,and the lower Tengger formation reservoir was divided into four types.All types of reservoirs have similar pore structure and seepage characteristics.The lower Tengger formation reservoir mainly develops class Ⅲ and Ⅳ reservoirs,dominated by sheet sand,distal bar microfacies and shore shallow lake subfacies.According to the classification results of flow units,the well logging physical property model of the reservoir was established.Through single well verification,the model has a certain regional applicability and high reliability.The formation of complex coarse-grained sandstone reservoir physical property interpretation technology based on flow unit classification can effectively guide the physical property prediction of this kind of reservoir.