多尺度岩溶相控碳酸盐岩缝洞型油藏储集体建模方法

Modeling method of carbonate fractured-cavity reservoirs using multiscale karst facies-controlling

以塔河油田为代表的碳酸盐岩缝洞型油藏是中国近年来投入开发的大型油藏,其储集空间类型主要为大型溶洞、溶蚀孔洞及裂缝,且尺度大小悬殊,形态不规则,分布不连续。定量表征孔、洞、缝在三维空间的分布一直是该类油藏开发的技术难题,目前尚缺乏有效的储层建模方法。以塔河油田4区碳酸盐岩缝洞型油藏为原型,研究并提出了多尺度岩溶相控缝洞储集体建模方法,即在古岩溶发育模式控制下,根据缝洞尺度的差异,采用两步法建模:笫1步建立4个单一类型储集体离散分布模型,即利用地震识别大型溶洞和大尺度裂缝,通过确定性建模方法,建立离散大型溶洞模型和离散大尺度裂缝模型;在岩溶相控约束下,基于溶洞发育概率体和井间裂缝发育概率体,采用随机模拟多属性协同模拟方法,建立溶蚀孔洞模型和小尺度离散裂缝模型。第2步采用同位条件赋值算法,将4个单一类型储集体模型融合成多尺度离散缝洞储集体三维分布模型。该模型的建立定量表征了缝洞储集体在三维空间的展布特征,可以为油田开发奠定坚实的地质基础。

Fractured-cavity carbonate reservoir represented by the Tahe oilfield in recent years in China is in the development of the large reservoir.The reservoir space types are mainly large caves, dissolved holes and multiscale fractures. Scale size disparity, irregular shape, and distribution are not continuous. Quantitative characterization of reservoir in 3D spatial distribution has been a technical problem, there is still lack of effective reservoir modeling method. In this paper, taking Tahe fractured-cavity carbonate reservoirs as the prototype,multiscale karst facies-controlling fractured-cavity carbonate reservoirs modeling method was studied and proposed. This method under control of the ancient karst development mode, according to the differences of measure, using two step modeling method： The first step is in the establishment of four discrete distribution models of a single type of reservoir, namely the use of seismic identification and description of the results, the establish certainty a large cave discrete distribution model and large-scale fracture discrete distribution model, in karst facies constraints, based on the probability of caves and fractures development body between the body and the wells, multi-attribute co-simulation, and the establishment of the dissolved holes stochastic model, and the small scale fractures discrete model; The second step is using parity conditions assignment algorithm, four single type of model integrae into multi-scale discrete fractured-cavity reservoir 3D distribution model. Quantitatively characterize the distribution characteristics of fractured-cavity reservoir in 3D space has laid a solid geological foundation for oilfield development.