Research On Pressure Conduction Characteristics Of Gas Water In Tight Reservoir

The gas-liquid seepage flow and pressure conduction is abnormal in tight reservoirs,that result in the related issues cann't be researched and analyzed by classic Darcy flow theory and Klinkenberg theory.In order to solve this problem,the pressure conduction characteristics of gas and water in tight cores are studied by using a simulation experiment.Reduce the experimental error of the pressure conduction in tight cores caused by the high-elasticity rubber seals in conventional experimental greatly by inventing Heat-shrinkable and sealed multi-point test device.Do research on the abnormal seepage and influencing factors of N₂ in tight cores,the result of experiment indicates that the smaller the pore throat,the critical pressure that the N₂ seepage begin to deviate the Klinkenberg theory and the maximum deviation can up to an order of magnitude or more.Moreover,the smaller the pore throat,the deviation between the gas measuring extreme permeability and Klinkenberg permeability greater.The gas measuring permeability is related to pressure gradient under high pressure in tight cores.The permeability of N₂ decreases with increasing pressure gradient at low pressure,and increases with increasing pressure gradient under high pressure.Do research on pore throat,apparent permeability,pressure and pressure gradient's influences on the pressure conduction in tight cores of N₂ and water by heat-shrinkable and sealed multi-point test device.The experimental result indicates that the rate of pressure conduction of N₂ decreases sharply in cores and the time of pressure's balance costs from 9 minutes to 900 minutes with the decrease of permeability.Moreover,the pressure in cores higher,the speed of pressure conduction lower.What's more,the permeability lower,the pressure's effect on the speed of pressure conduction greater.It proves that the speed of pressure conduction of inject gas is very slow in the actual reservoir under the high pressure.It's very difficult to establish effective driving differential pressure in the deep reservoir.