陇东油田长效清防垢工艺研究与应用

实验针对陇东油田的结垢现状与特点,分析了结垢机理及其影响因素,研究了适合处理该油田油层结垢的化学剂进行清防垢的工艺技术。研究表明:对井筒内以碳酸钙垢为主的油井井筒内防垢选用浓度为2 mg/L的(羟基乙叉膦酸)HEDP的防垢剂;对以硫酸钡垢为主的油井井筒内结垢可选由(聚天冬氨酸)PASP与(乙二胺四甲叉膦酸)EDTMP按3:2复配而成,其质量浓度为50 mg/L的防垢剂;对马岭侏罗系油藏油井井筒内既有碳酸钙又有硫酸钡垢的预防,可选用浓度为30 mg/L的JN-518防垢剂;对地层中既有碳酸钙垢又有硫酸钡垢的油藏内部防垢可用JN-518防垢剂,其浓度应随注水时间的改变而改变。现场试验表明:井筒和地层内加入实验室研究的清防垢剂后,清防垢率明显上升,经济效益显著。

RESEARCH AND APPLICATION OF LONG-TERM SCALE REMOVAL AND PREVENTION PROCESS IN LONGDONG OILFIELD

According to the characteristics of scales of Longdong Oilfield,the scaling mechanism and the influencing factors are analyzed,and the suitable chemicals to prevent the oil reservoir scaling are studied.Laboratory studies show that HEDP scale inhibitor at 2 mg/L concentration is suitable to prevent mainly the calcium scale in Hua 152 block and Xifeng Triassic wellbores.Composite scale inhibitor with PASP to EDTM of 3:2,at concentration of 50 mg/L is suitable to prevent mainly the barium scale.To Jurassic oil reservoir wellbores in Maling oilfield which have both barium and calcium scales,JN-518 scale inhibitor of 30 mg/L concentration iS used.Also to the formation of calcium and barium scales in the Triassic and Jurassic reservoir,JN-518 can be used as anti-scaling agent,with the concentrations being changed with the injection time.Field application shows that after using antiscaling agents to the wellbore and formation,the rate of scale removal and prevention increases appreciably,and the economic benefit is notable.