基于精细岩相约束的致密低渗储层参数建模研究——以红河油田92井区长812致密砂岩储层为例

鄂尔多斯盆地红河油田属于低孔、超低渗岩性油气藏.红河油田长8储层主要发育辫状河三角洲前缘水下分流河道和分流间湾两种沉积微相，并且在水下分流河道沉积微相中储层参数变化范围大，非均质性强，用常规的单一沉积相控建模方法无法对储层参数空间分布的非均质性进行充分表征.为了精确描述其储层参数及展布特征，以红河油田92井区长8₁²致密砂岩储层为例，在地质、岩心、测井等资料的基础上，应用基于精细岩相约束的储层参数建模方法建立了研究区三维地质模型，即先用沉积相发育模式约束建立沉积微相模型，再对水下分流河道沉积微相进行岩相细分，在沉积微相模型和不同岩相概率体的双重控制下建立岩相模型，然后以岩相模型为约束建立储层参数模型.结果表明，该方法建立的储层参数模型具有较高的可靠性，与地质认识符合较好，为该区油藏数值模拟提供了精确的地质模型，并为研究区下一步开发方案调整提供了地质依据.

PARAMETER MODELING OF LOW PERMEABILITY TIGHT RESERVOIR BASED ON FINE LITHOFACIES CONSTRAINT: A Case Study of C-812 Tight Sandstone Reservoir in No. 92 Wellblock of Honghe Oilfield

The Honghe Oilfield in Ordos Basin is a kind of lithologic reservoir with low porosity and ultra-low permeability, among which the C-8 reservoir mainly develops two types of sedimentary microfacies, including underwater distributary channel and interdistributary bay of braided-river delta front. The reservoir parameters of the former vary widely with strong heterogeneity, and the spatial distribution cannot be adequately characterized by conventional single sedimentary facies-controlled modeling. To accurately describe the reservoir parameters and distribution characteristics, taking the C-8₁² tight sandstone reservoir in No. 92 wellblock of Honghe Oilfield as an example, the reservoir parameter modeling method based on fine lithofacies constraint is applied to establish the 3D geological model on the basis of geology, core and well logging data. That is, first using the sedimentary facies development pattern constraint to built sedimentary microfacies model, then subdividing the lithofacies of underwater distributary channel microfacies, and establishing the lithofacies model under the dual control of sedimentary microfacies model and probability bodies of different lithofacies, and finally the reservoir parameter models based on lithofacies model constraint. The results show that the reservoir parameter model established by this method is highly reliable and consistent with geological understanding, which provides accurate geological models for reservoir numerical simulation and basis for further development adjustment in the study area.