子长油田长2油层酸化解堵技术

子长油田长2油层从1997年大规模开发以来,主要依靠自然能量开采,随着开采年限的增加,地层压力逐步下降,近井地带结垢严重,出现卡泵甚至停产,直接影响油井产量。在对该区储层矿物成分详细分析的基础上,对酸液体系进行筛选优化,采用10%盐酸+2%冰醋酸+3%氟硼酸+2%氢氟酸+1%缓蚀剂+1%活性剂+1%助排剂+2%黏土稳定剂+1%铁离子稳定剂+1.5%防膨剂+1%清蜡剂配方,试验效果较好。在子长油田余家坪等区块88口井的现场试验中,酸化解堵有效率在75%以上,平均单井增油39.6t,有效期半年左右。该措施工艺技术简单,成本低,见效快,成为近年来长2油层挖潜改造的主要措施之一。

Experimental study on acidizing and shutoff removing technologies of Chang-2 reservoirs in Zichang Oilfield

Since the large-scale development in 1997, Chang-2 reservoir of Zichang Oilfield has mainly been produced under natural energy drive. With time going by, the formation pressure declines step by step and the oil reservoir near the well area is getting more and more foul, which causes the pump to be stuck and even off production. As a result, the output of oil wells decreases a lot. Based on analyzing the reservoir mineral composition in this area, this paper selects and optimizes the acid system by using such compositions as hydrochloric acid 10%, glacial acetic acid 2%, fluo boric acid 3%, hydrofluoric acid 2%, anti-corrosive agent 1%, active agent 1%, cleanup additive 1%, clay stabilizer 2%, ferric ion stabilizer 1%, antiswelling agent 1.5%, paraffin remover 1%. The result of the experiment is satisfactory. The new technology is applied in 88 wells in the blocks of the oilfield, such as Block Yujiaping, with the efficiency of acidizing and shutoff removing achieving more than 75%, the oil recovery from the average single well enhancing by 39.6 t, and the term of validity being about half a year. The new technology features in simplicity, low cost, and high efficiency, which has been one of the major measures to reconstruct Chang-2 reservoir in recent year.