海相少井潜山缝洞型碳酸盐岩三维地质建模方法研究

Study on 3D geological modeling method of marine fracture-cavity carbonate rock with few wells buried hill

南海西部北部湾盆地涠西南凹陷N油田为海相碳酸盐岩潜山储层,潜山型储层发育广泛、储量规模大,受构造活动、风化淋滤和溶蚀作用等影响,碳酸盐岩潜山溶洞、裂缝、孔隙等储集空间发育。孔洞缝同时发育造成物性尺度差距大,空间连通性与储层非均质性的表征困难。目前潜山油田地质建模比较流行的方法有随机建模及离散裂缝建模等。此次以南海西部北部湾盆地涠西南凹陷N油田为例,提出了离散裂缝建模融合地质统计学随机建模的新方法,建立潜山储层多孔介质模型,主要是采取离散裂缝模型随机建立裂缝模型,利用地质统计学概率约束建立孔洞模型。N油田的研究结果,能够有效表征流体颜裂缝突进的特征。该方法有望为海上碳酸盐岩地质建模提供新的切入点或思路。

Noilfield in Weixinan sag of the Beibu Gulf basin in the west of the South China Sea is a marine carbonate buried hill reservoir.Buried hill reservoirs are widely developed and have large reserves.Affected by tectonic activities,weathering,leaching and dissolution,carbonate buried hill karst caves,fractures,pores and other reservoir spaces are developed.The simultaneous development of pores and fractures results in large physical property scale differences,and it is difficult to characterize the spatial connectivity and reservoir heterogeneity.At present,the popular methods for geological modeling of buried hill oilfield include stochastic modeling and discrete fracture modeling.This time,taking N oilfield in Weixinan sag of the Beibu Gulf basin in the west of the South China Sea as an example,a new method of combining discrete fracture modeling with geostatistical stochastic modeling is proposed to establish a buried hill reservoir porous media model,mainly by randomly establishing a fracture model using discrete fracture model and establishing a hole model using geostatistical probabilistic constraints.The research results of N oilfield can effectively characterize the characteristics of fluid face fracture protrusion.This method is expected to provide a new entry point or idea for offshore carbonate geological modeling.