非均质复杂断块油藏沉积微相研究及应用

Study on sedimentary microfacies of heterogeneous complicated fault-block reservoir and its application

桥口油田位于东濮凹陷的中部,属典型的非均质复杂断块油藏,由于油藏主力高渗层见效水淹,低渗层水驱动用难度大,使得综合含水急剧上升,年产油量大幅度减少.根据沉积微相与储层岩性、物性及与剩余油分布关系的研究,采取开发对策,对有利的河道微相带(T)部署调整井挖掘水动力滞流区剩余油.对储层物性较差的河间砂及远砂微相带(Q,Y)剩余油相对富集的部分干层、未解层、油水层重新认识,从中优选后进行挖潜.对微相过渡带,引入"隔相注水"模式,提高了低渗层水驱动用程度,减缓油田自然递减.开发实践证实:以沉积微相研究为基础,对非均质油藏实施分微相带系统开发,可以较好改善油藏开发效果;沉积微相研究是挖掘非均质复杂断块油藏层间潜力,实现开发层系由高渗层向低渗层转移的一种有效途径.

Locating at the center of Dongpu sag, Qiaokou oilfield is a typical heterogeneous complicated fault block reservoir. In recent years, because main high permeability layers are watered out and there are the difficulties of waterflooding in low permeability layers, the overall water cut of the oilfield increases sharply and annual oil production declines quickly. On the basis of the study on the relationship between sedimentary microfacies and the lithology, physical properties and remaining oil distribution of the reservoir, the different ways to tap remaining oil are applied to different sedimentary microfacies . Some adjustment wells are drilled in the favor river channel microfacies deposit to tap the remaining oil in hydrodynamic stagnant area. For the channel sand microfacies and distal sand microfacies with poor physical properties, some nonpay zones, unknown zones and oil water zones are studied firstly, then optimum zones are sought to tap. For the transitional zones between microfacies, the model of 'water injection to separate microfacies' is adopted to improve the effect of waterflooding in low permeability layers and to slow down the natural decline of oil production. The development practice proves that on the basis of the study on microfacies deposit, the systematic development of heterogeneous oil reservoir according to different microfacies can improve the development effect of this kind of reservoir, therefore, the study on microfacies deposit is useful to tapping the potential of heterogeneous complicated fault block oil reservoir and carrying out the development shift from high permeability layers to low permeability layers.