Percolation Feature In Low-Permeability Reservoir And Study On Inflow Performance Of Oil Wells

There are many differences between the low permeability reservoirs and the conventional reservoirs ,including that the fracture developed areas exist mostly, the filtration theory diverges the Darcy's law and the permeability and the porosity are more sensitive to stress in the deformed media reservoirs, which puts forward a higher demand to the inflow performance of oil wells and production forecasting.It has received more and more attention that how to study the inflow performance in the low permeability reservoirs comprehensively using the theories that have been established, establish the inflow performance modules with the wide applicability and unified form and comprehensively analyze the sensitive factors to confine the effective development of reservoirs, which is important to enhancing the level and effect of development for low permeability reservoirs.The author analyzes the characteristics in the low permeability and filtration theory, experimentally studies the starting pressure gradient of the low permeability core and establishes the correlation between the starting pressure gradient and the permeability. Making use of the non-equivalent diameter capillary module, the author theoretically analyzes the sensitivity to stress of the permeability and the porosity in the low permeability deformed media reservoirs. The single phase flow productivity equation for the low permeability non-deformed media reservoirs, the deformed reservoirs and the fracture reservoirs derives from the filtration theory of the non-Darcy's law, which is used to analyze the inflow performance of oil wells. Because the mobility function is binomial, the author establishes the empirical inflow performance equations for depletion drive in the low permeability non-deformed media and deformed reservoirs, whose calculated value is good agreement with the measured value. It is indicated that the equations established above are reliable. Meanwhile, the author applies oil-water relative flowing capability equations to three-phase flow case in the oil-gas-water reservoirs, analyzes the influent factors on production of oil wells, which can be used to enhance the effective development of the reservoirs.