酸性气田暂堵压井体系的研制与应用评价

Development and Application of Temporary Plugging and Killing System Suitable for Sour Gas Field

许 园 唐永帆

XU Yuan，TANG Yongfan

针对川渝地区酸性气田（含H2 S、CO2 、SO2 等酸性气体）生产井修井作业过程中常规修井液存在的安全性差、易漏失、对储层污染大等问题，通过优选植物胶稠化剂、调节pH值、添加抗酸抑制剂等得到了一种适用于高含酸性气井液体胶塞体系，考察了该体系的流变性能以及成胶后的承压能力、抗温稳定性、抗硫化氢稳定性、破胶性能，并开展了高含酸性气井的现场应用。配方为3%稠化剂+3%稠化分散剂+7%交联剂+5%调理剂+1%抗酸抑制剂+调节剂的液体胶塞的成胶时间的可控可调范围为28～200 min，成胶后的黏度大于30 Pa·s，成胶强度高；在150 ℃老化24 h不破胶，在70 ℃的酸性气层水（H2 S含量300 mg/L或CO2 含量100 mg/L）中72 h不破胶。液体胶塞体系在pH=8时的承压能力最佳；在50～80 ℃温度区间内，解堵液能让液体胶塞在1～6 h完全破胶至黏度低于3 mPa·s。液体胶塞体系已在硫化氢含量约为80 mg/L的A井成功应用，为川渝地区酸性气田的修井作业提供了技术支撑与保障。

In view of the problems of poor safety，leakage and large reservoir pollution in the process of workover of sour gas fields containing H2S，CO2，SO2 and other acid gases in Sichuan and Chongqing area，a liquid gel plug system suitable for high-acid gas wells was obtained by optimizing vegetable gum thickener，adjusting pH value，adding antacid inhibitor. The rheological properties of the system，as well as the pressure bearing capacity，temperature stability，hydrogen sulfide resistance，and gel breaking performance after gel formation were investigated，and the field application in high-acid gas wells was carried out. The gelling time of the system，composed of 3% thickener，3% thickening dispersant，7% cross-linking agent，5% conditioner，1% acid inhibitor and regulator，was adjustable from 28 min to 200 min. The viscosity after gelling was greater than 30 Pa·s，indicating that the strength of the system was high. The gel did not break after aging for 24 h at the temperature of 150 ℃，and the gel did not break when soaked in the acid gas layer water containing 300 mg/L H2S or 100 mg/L CO2 for 72 h. The pressure bearing capacity was the best when the pH value of the system was 8. When adding the blockage relieving fluid，the liquid gel plug could be broken within 1—6 hours at the temperature of 50—80 ℃，and the viscosity of the broken fluid was lower than 3 mPa·s. The liquid gel plug system had been successfully applied in wells with H2S content of 80 mg/L，which provided the technical support and guarantee for the well repair in Sichuan and Chongqing acid gas field.

10.19346/j.cnki.1000-4092.2022.03.001