三维地质模型概率法在碳酸盐岩缝洞型油藏石油地质储量研究中的应用——以塔河油田四区为例

Application of probability method of 3D geological model for petroleum geologi cal reserves in fractured-cavity carbonate reservoirs:a case of Tahe-IV district,Tahe oilfield

碳酸盐岩缝洞型油藏孔、洞、缝储集体类型共存,规模相差悬殊,形态不规则,分布不连续,定量表征有效储集空间难度大,准确计算该类油藏石油地质储量一直是开发的技术难点。为此,研究并提出了基于三维地质模型的概率法,即在单井缝洞储集体识别及井间储集体预测的基础上,采用确定性建模与随机建模相结合的方法建立一系列等概率地质模型,在三维地质模型网格数据体上求取有效缝洞储集体体积,依据孔、洞、缝等不同储集体类型分别计算石油地质储量,统计石油地质储量概率分布。塔河油田四区计算的最可能的石油地质储量为5 665×104t,最悲观的石油地质储量为5 470×104t,最乐观的石油地质储量为5 914×104t,计算结果与塔河油田开发生产现状基本一致。结果表明,基于三维地质模型的概率法充分考虑储层的非均质性,计算的石油地质储量更为精确,细化了石油地质储量的构成,明确了石油地质储量的有利富集区。

The fractured-cavity carbonate reservoir spaces,including pores,caves and fractures,have varied scales,irregular shapes and discontinuous distribution.Quantitative characterization of effective reservoir space is difficult,and the accurate calculation of petroleum geological reserves of the reservoir is the key to technical difficulties.Therefore,the probability method based on 3D geological model was studied and discussed.Based on the single well fractured-cavity reservoir identification and reservoirs prediction between wells,a series of geological models of equal probability were established by methods of deterministic modeling and stochastic modeling combined.According to the 3D geological model of grid data,the effective fractured-cavity reservoir volume was calculated.On the basis of pores,caves and fractures of the 3D geological model,the petroleum geological reserves were computed separately,as well as the statistical probability distribution of petroleum geological reserves.The most likely petroleum geological reserves of Tahe-IV district is 5 665×104t,the most pessimistic is 5 470×104t,the most optimistic is 5 914×104t,and the calculation reserves results and the Tahe oilfield production situation is basically the same.The results show that,by means of the probability method based on 3D geological model considering the heterogeneity of reservoir,the oil geological reserves calculation is more accurate,and it can detail the composition of petroleum geological reserves,and can point out the favorable petroleum geological reserves accumulation area.