厚油层顶部微米凝胶封堵实验研究

Experimental study on micron mesh gel plugging at the top of thick oil layer

海上X油田储层厚度大,地质储量丰富,自实施弱凝胶驱以来,取得了较高的经济效益和开发效果。随着弱凝胶注入量持续增大,注入剖面发生变化,注入水严重突进,油田整体含水率上升较快,开展弱凝胶注入井吸液剖面分析,认为弱凝胶驱注入后期厚油层顶部吸液量达90%,中低渗层吸液较少,部分储层不吸液,并针对吸液厚度较大的厚油层顶部提出微米网状凝胶封堵措施。实验结果表明,微米网状凝胶增粘性较好,体系强度达到14866mPa·s,且岩心剪切后仍具备较强的体系强度。填砂管岩心实验表明,体系具有较强的封堵能力和液流转向作用,破胶剂浓度为1%时,凝胶失水率超过80%。

Offshore X oilfield has a large reservoir thickness and rich geological reserves.Since the implementation of weak gel flooding,relatively high economic benefits and development results have been achieved.With the continuous increase of the injection amount of weak gel,the injection profile changes,the injected water is seriously inrushed,and the overall moisture content of the oil field rises rapidly.Therefore,the analysis of the suction profile of the weak gel injection well was carried out,and the micron mesh gel plugging measures were proposed for the top of the thick oil layer with large suction thickness.The experimental results showed that at the later stage of weak gel flooding,the liquid absorption at the top of thick reservoir was up to 90%,less in the middle and low permeable layer,and some reservoirs do not absorb liquid.Micron reticular gels had good viscosity enhancement,and the system strength reaches 14866mPa·s.Moreover,the core still had strong system strength after shear.The results showed that the system had a strong liquid flow,and the gel water loss rate was more than 80%when the concentration of gel breaker was 1%.