| Carbonate fractured-cavity reservoir occupies a very important position in the world’s oil and gas resources. This kind of reservoir has a large scale in reserves and its reservoir properties are very complexly. In addition, its exploration and development of the technology are at the exploratory stage, and the existing research work can not meet the needs of the development of this kind of reservoir either in the practice part or in the theory part. The purpose of this article is to study the adaptation of gas injection flooding in the fractured-cavity reservoir. The gas injection displacement mechanism in fractured-cavity reservoir is studied through the fluid phase state characteristics experiment, visual models and full diameter core experiments.Choose the typical carbonate reservoirs in Tahe4areas S48unit as the target. By conducting the unit water injection, Tahe Oilfield has obtained the good effect. But with increasing injection-production ratio, oil production speed rapid decline in each unit. An alternative development way need to be studyed. This paper study respectively from crude oil solubilization ability and viscosity and gravity differentiation, formation energy distribution and fractured-cavity combination structure, and flooding mechanism of gas injection in S48unit is analyzed. Formation fluid was analyzed in the experiment of phase behavior characteristics, and the sample is black oil. In the high temperature and high pressure full diameter core experiments adopted the water drive, gas drive, water drive way for research. Further understanding to the above three kinds of gas through the experiment the performance difference of the specific impact of heavy oil by flooding effect. The fractured-cavity reservoir oil displacement mechanism is based on gravity differentiation through model channel plugging and the changed core gripper inclination of the contrast experiment. Organic glass visual model experiment is according to water-gas-water drive way for research. For fractured-cavity reservoir height distribution, the number of opening direction, the direction of fracture development, crack width and other parameters on the influence on the effect of gas injection flooding has obtained more profound intuitive understanding.Conclusions are as follows:Water-gas-water drive way is very effective in fractured-cavity reservoir, the use of gas injection displacement measures can effectively use unswept attic oil after water flooding. And gravitational differentiation is the main gas drive mechanism. Thesis results of fractured-cavity reservoir gas injection development has a certain reference value. |
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