Researches On Steam Flooding Technique In Chaoyanggou Oilfield Of Ultra-low-permeability And Thin-petroleum

The reservoir of Chaoyanggou Oilfield is of low to ultra-low permeability , high viscosity and thin petroleum . Its development performance is detrimented by high oil flowing resistance caused by lower permeability and higher oil viscosity. In order to develop one new way to enhance liquid flowing ability and to lower flowing resistance , steamflooding experiment is launched on the class No.2 block of Chaoyanggou Oilfield . Because of the disadvantageous factors such as the low permeability , high oil visocosity , and high clay-content in cement , physical-model test is conducted in order to testify the feasibility of steamflooding . Then , through numerical simulation , steam injection parameters include injection rate , dryness fraction , temperature and pressure are optimized . Meanwhile , the technique of anti-clay-swelling , vacuum heat-shielding string in company with nitrogen-injection-in-annula r-space (one heat shielding mesure) is practised . After gross 9.6×104t steam is injected in three injection wells , oil production of the fourteen communicated production wells increase accumulatively in 1.81×104t , getting an encouraging result . This technique is for the first time be applied to high-viscosity low-permeability thin-petroleum reservoirs . It overthrows the conventional opinion that it could only be used in medium and high permeable reservoirs , also breaks the technical limit of steam flooding including permeability , porosity , net/gross-pay-thickness ratio . The limit of permeability reduces from 200mD to 5.0mD,porosity from 20% to 16%,net/gross-pay-thickness ratio from 0.5 to 0.2 . This technique find out an innovative way to increase recovery for Chaoyanggou and other alike oilfields of high-viscosity low-permeability and thin-petroleum .