文23气田低伤害酸化工艺技术研究与应用

STUDY ON LOW DAMAGE ACIDIZING TECHNIQUE IN WENLIU 23 GAS FIELD

文23低渗气藏具有埋藏深、物性差等特点,通过常规酸化对文23气田储层伤害的分析,研制出了气井低伤害酸液,筛选出防水锁剂JIX-Ⅱ、酸化缓蚀剂HSJ-Ⅱ等低伤害酸化添加剂,酸体系表面张力≤23m.N/m,界面张力≤0.5m.N/m,腐蚀速度<5g/m2.h(90℃)。室内岩心流动实验表明酸液具有较高的储层渗透率改善效果及较低的储层岩心伤害率。低伤害酸液体系与新型撬装气举残酸反排工艺的应用使得储层残酸、井筒积液反排彻底,提高了气井酸化效果。经过在文23气田15口井次的现场应用,平均单井日增气4.5×103m3,平均有效期132d。表明该气井低伤害酸化工艺技术对于文23气田低渗气藏酸化改造具有良好的增产效果和广阔的推广应用前景。

Wenliu 23 oilfield, belonged to low permeability gas reservoirs, has some representative characters, such as deep burial depth, poor physical property, and etc. This thesis analyzed the damage of acidizing treatment in Wenliu 23 gas field, and developed a low damage acidizing fluid, and screened out some low damage acidizing additives, such as prevention water-lock additives JIX-Ⅱand corrosion inhibitor HSJ-Ⅱ and so on. The performances of the new acidizing fluid were obtained by laboratory evaluations: low damage for formation, low surface and interfacial tension(≤23 and ≤0.5 mN/m, respectively), low corrosive rate (≤5 g/m2·h, 90℃). The indoor experiment by core flowage grads instrument showed that the low damage acidizing fluid could improve the permeability of gas reservoir and had lower core damage ratio than any other acids. Furthermore, on the basis of applying skid-mounted gas lift, reacted acid which stay in gas reservoirs and wellbore was uploaded completely by this way. This technique combined with skid-mounted gas lift and low permeability acid could improve the effect of gas well acidizing. Up to now, the low damage acidizing technique has been applied more than 15 wells in Wen 23 gas field. The average single-well gas increase volume per day was 4.5×103m3, and the average period of validity was 132 day. The field application results showed that the combined technique has the better result of increase production and wide application prospects.