普光高酸性气田环空保护液的研制与应用

Development of an Annular Protection Fluid and Its Application in Puguang Sour Gas Field

研制的无固相体系的环空保护液是以有机酸盐为基液,添加抗硫缓蚀剂、杀菌剂和除氧剂调配而成。现场应用结果表明,该环空保护液体系密度调节范围广,达1.00～1.30 g/cm^3,可满足不同井深条件下的需要;溶液热稳定性好,抗高温能力强,可适合高温条件下的需要;pH为9.5～12,易于调节,不易引起金属腐蚀(碳钢腐蚀速率≤0.076 mm/a),可起到良好的环空保护作用;地层伤害率较低,对环境无污染,且成本合理,能够确保油套管长期安全使用,适宜在含硫油气藏推广应用。

A solid free annular protection fluid system was prepared by mixing a sulfur corrosion inhibitor, a bactericide and an oxygen scavenger to a base solution of organic acid salt. According to the results of field application, the density of this annular protection fluid can be adjusted in wide range, i.e. from 1.00 to 1.30 g/cm3, and therefore it can satisfy the requirement for use at different well depths. The solution is thermally stable and has high temperature resistant performance, and therefore the annular protection fluid can be used at high temperatures. The pH value of the annular protection fluid can be adjusted in the range of 9.5 to 12 easily, and therefore it is not prone to causing the corrosion of metals （ e. g. the corrosion rate of carbon steel is ~〈0.076 mm/a when the annular protection fluid is used）. It has good annular protection performance with small damage to formation and no contamination to environment, and its cost has been justified as well. It can ensure the long - term use of oil casing, and is suitable for use in sulfur containing oil and gas reservoirs safely.