Study On Air Foam Flooding In Tang 80 Area Of GanGuYi Oilfield

Currently, special low permeability sandstone reservoirs has become the main force of onshore oil field, due to the economic development, China’s consumer demand for oil is also growing, energy security issues are also the focus of our attention, therefore, how to Low infiltration, especially low permeability reservoir development has become the focus of our attention. Low permeability reservoir using conventional waterflooding poor mining results. How effective exploitation of low permeability oilfield, developed into a serious problem. In this paper, Tang 80 wells Ganguyi oilfield area as an example of the air foam flooding has been studied, it has important significance in guiding the development of low permeability reservoirs. Main achieved the following understanding:(1) of the study area mainly residual intergranular pass, intergranular pore-corrosion hole, followed by a small amount of oil dissolved pore-pore type, and composite pass, micro-cracks do not develop.(2) study CHANG6 strong acid Min Min Weak, weak salt sensitivity, weak velocity sensitivity for waterflooding, also suitable for injection foam fluid system development.(3) reservoir formation water salinity especially high calcium content of conventional foam fluid system relatively large, stable bubbles from bubble to bubble up liquid stability, and so have different effects.(4) After a number of laboratory experiments, combining Ganguyi oilfield basic characteristics determine the foam fluid system to meet the requirements:basic recipe 0.1-0.8% BK-6+0.02-0.1%BK-51. The pilot test is recommended to use 0.5% BK-6+0.05% BK-51 compound from the foam system. (BK-6 as a main component oxide lauryl dimethyl ammonium and octadecyl trimethyl ammonium chloride; BK-51 is mainly composed of an alkyl sulfate and ethoxylated nonylphenol with ethylene alkyl adducts).(5) The preferred foam liquid formulations with good foaming performance and foam stability, salt is good, applicable to the formation of ground water with high salinity.(6) Preferred liquid foam formulations and oil formation fluid Ganguyi good compatibility, suitable PH value neutral system.(7) Preferred foam formulations corrosive liquid, low interfacial tension, low foam liquid viscosity, foaming bubble after moderate viscosity to meet Tang 80 wells area air-foam flooding pilot test requirements.(8) Tang 80 wells district core flooding experiments show that the development of foam liquid flooding, compared with water flooding, flooding more than 20% efficiency.(9) The low permeability cores, air foam flooding pressure rises quickly and displacement pressure is high, and the air-foam liquid slug displacement pressure rises slowly and flooding low pressure.(10) displacing air-foam liquid slug, gas-liquid ratio increases, effective the sooner, the sooner channeling gas; the lower liquid ratio, effective slower, gas channeling the more late.(11) A single injection of foam concentrate is not conducive to effectively improve oil displacement efficiency, single displacing a large slug of air-foam liquid easily lead to gas migration, gas migration occurs when the amount of displacement 0.6-0.8PV.(12) suggested that field trials should be controlled in the gas-liquid ratio of 1:1 to 4.5:1 between; site construction should adopt the pill more slug mode; injection method should be based on "air-foam liquid-air-foam liquid" alternately.