潍北油田特低渗透油藏酸化增产技术研究应用

Research on acid stimulation of Extra-low permeability reservoir in Weibei Oilfield

摘要: 潍北油田昌36区为特低渗透油藏,油层供液能力差,需进行基质酸化。针对该区块储层矿物成分特点研制了乙酸(YS)酸化配方,其溶蚀能力为常规土酸的93.1%,相对缓速率为65.2%。通过酸岩化学反应、扫描电镜和X衍射全岩矿物分析,对酸化机理进行了分析,该酸化液主要溶蚀储层中的胶结物(方解石、白云石和粘土矿物),使储层骨架结构保持较好。酸化配方现场应用于昌36区的昌27-3井,日均增油量0.6 t,酸化增产效果显著。

Abstract: Chang36 block in Weibei oilfield is typical extra-low permeability reservoir with poor fluid supply in oil layer,which needs acidification.Based on the above characteristics,YS acid formula is developed.Its dissolution ability is93.1%and its anti-swelling ability is 65.2%.The mechanism which was analyzed by SEM and XRD,proves that the YS acid formula is proper for applications,Which acidizes cements in karst reservoir(including calcite,dolomite and clay minerals),and maintain good skeleton structure.Currently,the acid application to Chang 27-3 well leads to an average increase of 0.6t/d and achieves good result.