孤岛中一区注聚井二氧化氯解堵技术

Reservoir Blockage Relieving in Polymer/Water Injection Wells by Using Chlorine Dioxide in District M1 of Gudao Oil Field

胜利孤岛油田中一区一部分注聚井地层堵塞严重,常规酸化解堵效果不好,为此开发了二氧化氯解堵技术。室内实验结果表明:1%CMC和0 5%HPAM溶液与等体积0 4%ClO2溶液的混合液在60℃放置3小时后,粘度较空白混合液下降95%和87%;HPAM/Cr3+强凝胶在0 4%ClO2溶液中于80℃放置12h后解体,产生少量絮状沉淀;ClO2在加量30～200mg/L时在30～90min内基本上杀灭全部SRB菌(初始菌数2 5×104～≥1 1×108个/mL),在加量5～100mg/L时在5～60min内基本上杀灭全部TGB菌(初始菌数≥1 1×107个/mL);0 2%～0 8%ClO2溶液对FeS的溶蚀率为16 8%～23 1%,远高于15%盐酸液的5 3%;常温下ClO2对N80钢的腐蚀率符合现场施工要求。在4口注聚后恢复注水的井实施0 4%ClO2解堵,使平均注水压力由13 3MPa降至10 1MPa,注水量达到配注量,有效期79～325天,平均192天;10口对应采油井原油增产,其中7口油井增产显著,有效期107～301天,平均178 4天。表5参2。

In district M1 of Gudao, Shengli, severe reservoir blockages are created in some polymer/water injection wells and are fail to respond to the standard acidizing measures. To solve this problem, a reservoir blokages relieving technology using ClO_2 is developed. The laboratory experimental results show that the mixture of 1% CMC or 0.5% HPAM solution with 0.4% ClO_2 solution in equal volume has viscosity by 95% or 87% decreased after standing at 60℃ in 3 hrs as compared with the blank mixture; an HPAM/Cr^(3+) strong gel immersed in 0.4% ClO_2 solution at 80℃ breaks down in 12 hrs with a little amount of floccule produced; ClO_2 practically kills all bacteria SRB (initial population 2.5×10~4～≥1.1×10~8 cell/mL) at dosage 30-200 mg/L in 30-90 min and all bacteria TGB (initial population ≥1.1×10~7 cell/mL) at dosage 5-100 mg/L in 5-60 min; 16.8-23.1% of mass of FeS is dissolved out in 0.2-0.8% ClO_2 solution in comparison with 5.3% in 15% hydrochloric acid; ClO_2 solution meets the requirement in oilfield operations for corrosivity of N80 steel samples at ambient temperatures. Reservoir blockages relieving operations with ClO_2 (0.4% solution) performed in 4 water injection wells after polymer injection result in that the average injection pressure is decreased form 13.3 MPa to 10.1 MPa and the volume of daily water injection reaches the volume desired in a period of 192 days in average and ranged in 79-325 days; the oil output is increased to varying extents in 10 production wells connected with the injection wells and significantly in 7 wells of them in a period of 187.4 days in average and ranged in 107-301 days.