超低渗油藏注气采油可行性实验
Experimental study of feasibility of gas injection recovery in ultra-low permeability reservoirs
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摘要: 超低渗油藏由于孔喉极细,即使高压注水,也难以保持注采平衡,应考虑注气的可行性。文中进行了水驱油和氮气驱油试验,以比较驱替效果,探究超低渗油藏的驱替机理。结果表明,对于小于1×10-3μm2的超低渗岩心,气驱比水驱效果好,气驱平均采收率为27.9%,水驱平均采收率为24.1%。说明注气具有一定的优越性。Abstract: To maintain a balanced injection and production rate in ultra - low permeability reservoirs is very difficult even when applying a very high pressure water injection, due to the very fine pore throats, therefore the feasibility of gas injection should be considered. Water - drive and nitrogen - drive experiments are performed to compare their displacement effects and study the displacing mechanism of ultra - low permeability reservoirs. In core with an ultra - low permeability of 1×10-3μm2 , the average recovery factor of gas drive is 27. 9% , 3. 8 percentage points higher than the 24. 2% of water drive, indicating that gas drive is advantageous to some extent.