Study on the Reservoir Character and Seepage Flow of Different Types of Reservoir in Hailar-Tamuchage Basin
|School||seepage Institute of Fluid Mechanics|
|Keywords||low permeability reservoir pore structure sensitivity seepage flow of deformation reservoir movable fluid|
Combining with the physical simulation, mechanics of fluid flow in porous medium and numerical analysis, the paper studied the pore structure characteristics of low permeability sandstone, low permeability tuffaceous sandstone and low permeability glutenite. Then, based on the above research, the seepage flow law of the single phase fluid and two phase fluids seepage were studied.1. Compared with low permeability glutenite, pore structure, relation of throat radius and permeability and separation of low permeability sandstone and low permeability tuffaceous sandstone is similar. Compared to other Daqing low permeability reservoirs, the movable fluid percent and average throat radius of Halar-tamuchage reservoir is in the mid to upper level. It showed that the development results will be better than other reservoirs. Meantime, the results of mercury injection, constant rate mercury injection and NMR presented that the tamuchage reservoir is better than other low permeability reservoir of Halar-tamuchage basin2. Non-linear seepage flow deliverability equation of deformation reservoir was established. The results presented that more serious non-linear seepage flow degree and bigger deformation resulted in lower deliverability. Increasing drawdown will decrease the non-linear effect impact on the seepage flow, and improve the deliverability. However, the decreased extent of the permeability will be enlarged. So, production index have a maximum with the drawdown on the condition of low permeability deformation reservoir. It afforded a reference for the deliverability optimization of low permeability reservoir.3. New model for describing the mechanism of non-linear seepage flow was presented. The results showed that mobility and start-up pressure gradient are the main reasons of non-linear seepage flow effect. Meantime, the pressure gradient region, which producing the non-linear seepage flow, was calculated. Impact of start-up pressure gradient, mobility and microscopic pore structure on seepage flow has been researched.4. The distribution character of movable oil and irreducible oil in low permeability reservoir was presented. The irreducible oil distributes not only in small pore-throat, but also in the pore throat that is bigger than the cut-off pore-throat. Proportion of imbibition produced oil to the overall produced oil is different in different low permeability reservoir of Hailar-tamuchage basin. So, the reasonable flooding rate can be obtained by the proportion.5. The oil/water relative permeability model with non-linear seepage flow was established. The non-linear seepage flow impact on the oil/water relative permeability was analysed. The result showed that bigger pressure gradient will result in higher oil relative permeability and lower water relative permeability.6. Displacement model of non-linear seepage flow was showed. Research on the piston like displacement and non-piston like displacement was presented. Compared with Darcy seepage flow, on the condition of non-linear seepage flow, the drawdown is higher; the water cut is bigger; degree of reserve recovery is lower.