特低渗透油藏水平井减氧空气泡沫驱油藏方案优化设计

Optimization design of oxygen reducing air foam flooding reservoir scheme for horizontal wells in ultralow permeability reservoirs

为了提高特低渗透油藏水平井的开发效果,针对志丹油田河川区长6油藏水平井地层能量得不到有效补充,地层能量亏空严重,单井产量递减快等问题,探索利用减氧空气泡沫驱技术高效补充致密砂岩油藏地层能量,开展了减氧空气泡沫驱油藏方案的优化研究。利用数值模拟优化研究得到如下注入参数:根据当前井网形式,确定转注1口水平井作为减氧空气泡沫驱试验井,注入方式采用气液交替泡沫驱;2)初期泡沫液配注量60m^(3)/d,初期减氧空气配注量4500nm^(3)/d;3)段塞组成:0.003PV前置段塞×起泡剂浓度0.7%,0.197PV主体段塞×起泡剂浓度0.35%,泡沫驱总段塞:0.1PV;4)气液交替注入周期为15d;5)初期设计气/液比为3∶1(地下体积比)。该研究成果在试验井组应用,预测能取得较好的经济效益,为深化减氧空气泡沫驱应用研究,提高致密砂岩油藏的采收率奠定了技术基础。

In order to improve the development effect of horizontal wells in ultra-low permeability reservoirs,in view of the problems that the formation energy of horizontal wells in Chang-6 reservoir in Hechuan District of Zhidan oilfield can not be effectively supplemented,the formation energy deficit is serious,and the production decline of single wells is fast,we explored the use of oxygen reduced air foam flooding technology to efficiently supplement the formation energy of tight sandstone reservoirs,and carried out optimization research on the reservoir scheme of oxygen reduced air foam flooding.The following injection parameters are obtained through numerical simulation and Optimization Research:1)according to the current well pattern,a horizontal well is determined to be converted into an oxygen reducing air foam flooding test well,and the injection mode is gas-liquid alternating foam flooding;2)The initial foam liquid dosage is 60m^(3)/D,and the initial oxygen reducing air dosage is 4500 standard cubic meters/D;3)Slug composition:0.003pv front slug×Foaming agent concentration 0.7%,0.197pv main body slug×Foaming agent concentration:0.35%,foam flooding total slug:0.1pv;4)The cycle of alternating gas-liquid injection is 15 days;5)The initial design gas/liquid ratio is 3:1(underground volume ratio).The application of the research results in the test well group is predicted to achieve good economic benefits,which lays a technical foundation for deepening the application research of oxygen reducing air foam flooding and improving the recovery of tight sandstone reservoirs.