Reservoir Blockage Relieving in Polymer/Water Injection Wells by Using Chlorine Dioxide in District M1 of Gudao Oil Field
Reservoir Blockage Relieving in Polymer/Water Injection Wells by Using Chlorine Dioxide in District M1 of Gudao Oil Field
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作者：
Xue Ai
胜利孤岛油田M1区部分注聚威尔斯井储层堵塞严重，酸化措施无效。为解决这一问题，开发了二氧化氯解堵技术。室内实验结果表明，1%CMC或0.5%HPAM溶液与0.4%ClO_2溶液等体积混合后，在60℃下静置3 h，粘度比空白混合物下降95%或87%; HPAM/Cr~（3+）强凝胶在0.4%ClO_2溶液中浸泡12小时后即发生破裂，并产生少量絮体; ClO_2几乎杀死所有细菌SRB（初始菌数2.5×10~4~≥1.1×10~8个/mL），在30-90 min内，所有细菌TGB（初始菌数≥1.1×10~7 cell/mL），在0.2- 0.8%ClO_2溶液中，FeS溶出量为16.8-23.1%，在15%盐酸中溶出量为5.3%; ClO_2溶液对N80钢试样的腐蚀性满足油田作业对常温腐蚀性的要求。ClO_2在水库解堵中的应用注聚后4口注水威尔斯井进行了0.4%水溶液驱替，平均注入压力由13.3 MPa降至10.1 MPa，日注水量达到要求的时间为79-325 d，平均192 d;与注水威尔斯井相连的10口生产威尔斯井均有不同程度的增产，其中7口威尔斯井增产幅度较大，增产周期107-301天，平均187.4天。
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.