Note The Gas Miscible And Immiscible Displacement For The Establishment And Application Of Material Balance Equation

Theoretically, enhanced oil recovery by gas injection miscible flooding is better technique than that of water injection flooding. The efficiency of micro flooding can be a hundred percent as much as well known. In recent years, most of the oil reserves having been found are difficult to exploit because of the high viscosity and low permeability and so on. The new field in the west always lies at the marginal desert area and lacks water, which makes water injection flooding quite difficult. So gas injection miscible flooding technique becomes increasingly important in oil reservoir exploitation. In the initial stages of exploitation, we can gain such few data of oil reservoir that the use of many oil reservoir engineering methods have been limited. While material balance method need not take complex underground permeate characteristics into account, only need fewer geological information, fluid physical testing data and some productive performance information, and its calculation method and program is simple. So it has already been considered as one of conventional petroleum reservoir engineering approaches. We can learn from above that the study of material balance method during gas injection flooding is very important. On the base of reading much literature about material balance method, its applying methods and case studies, using the simulation test of gas injection miscible flooding, we study the transitional zone during gas injection flooding and put forward a material balance equation during gas injection flooding and its applied methods in this thesis. That is to say, when we develop one oil reservoir by gas injection flooding, how to calculate reserve and recovery ratio, how to apply it to the production determination and how to calculate the cumulative oil when the solvent has broken through. The laboratory and field case verify that the equation and its applied method established in this paper is precise and reliable, and can satisfy the need of engineering application.