靖安油田注水管线结垢原因分析及新型高效阻垢剂的研制

Scaling Analysis of Waterflooding Pipeline in Jing'an Oilfield and Study of a Novel High-Efficiency Scale Inhibitor

目的 解决靖安油田三号联合站注水管线内结垢问题。方法 采用扫描电镜和X射线衍射仪对注水管线内垢样进行分析,采用油气田水分析方法对各站区油水混合物的离子浓度进行分析。选取自制马来酸酐-丙烯酸羟丙酯-亚磷酸钠（MASP）、聚环氧琥珀酸（PESA）和乙二胺四亚甲基磷酸钠（EDTMPS）三种药剂为原料,采用正交试验法L9（34）研制出了一种新型高效阻垢剂Inhi-MPE。参照油田用防垢剂性能评定方法,评价了Inhi-MPE与常用阻垢剂PESA、AA/MA、PBTCA的阻垢性能。结果 注水管线垢样主要为Ca SO4结垢和少量的Ba（Sr）SO4垢。靖安油田三号联合站注水管线结垢主要是由两种不相容的水混合,并在注水管线中生成Ca SO4、Ca CO3和Ba（Sr）SO4垢。Inhi-MPE的最优水平组合为：MASP 10 g,PESA 7 g,EDTMPS 7 g。随着Inhi-MPE含量的增加,Inhi-MPE的阻垢性能增加。当Inhi-MPE的质量浓度为100 mg/L时,对靖安油田三号联合站混合水样的阻垢率达93.71%。在相同实验条件下,Inhi-MPE对靖安油田三号联合站混合水样的阻垢效果最优,AA/MA和PESA次之,PBTCA效果最差,表明Inhi-MPE具有优良的阻垢性能。结论 在靖安油田三号联合站注水中连续投加Inhi-MPE,平均注水量可控制在608～628 m^3之间变动,注水压力在8.15～8.27 MPa之间变动,两者变动基本保持不变。这说明Inhi-MPE可有效地减缓Ca SO4的结垢速度,保证了注水量的稳定和注入压力的平稳,注水管线结垢的问题得以解决。

Objective To solve the scaling problem of waterfiooding pipeline of No.3 United Station in Jing＇an Oilfield. Methods Scale samples were analyzed by using scanning electron microscope and X-ray diffraction method. Ionic concentration of oil-water mixture in each station was analyzed by the analysis on oil and gas field water. A novel high-efficiency scale inhibitor Inhi-MPE was developed by orthogonal test L9（34） with self-made maleic anhydride- hydroxypropyl acrylate-sodium subphosphite （MASP）, polyepoxysucc-inate （PESA） and ethylene diamine tetramethylene sodium phosphate EDTMPS） as raw materials. Scale inhibition performance of Inhi-MPE and commonly used PESA, AAJMA and PBTCA were evaluated according to evaluation method for behavior of inhibitor used in oil field. Results Scaling sample of the waterflooding pipeline was mainly made of calcium sulfate and a small amount of barium or strontium sulfate scale. The scale of waterflooding pipeline of No.3 United Station in Jing＇an was mainly mixed by two incompatible waters and produced the scale of CaSO4, CaCO3 and Ba（Sr）SO4 in the pipeline. The optimal level combination of the Inhi-MPE was MASP 10 g, PESA 7 g and EDTMPS 7 g. The scale inhibition performance of Inhi-MPE was improved with the increase of Inhi-MPE＇dosage. The scale inhibition rate to the mixed water sample of No.3 United Station in Jing＇an was 93.71% when the dosage of Inhi-MPE was 100 mg/L. The scale inhi- bition effect of Inhi-MPE was best, AA/MA and PESA successively, and PBTCA worst under the same experimental conditions. These indicated that Inhi-MPE had excellent scale inhibition performance. Conclusion When Inhi-MPE is added continuously to the mixed water of the No.3 United Station in Jing＇an, the average quantity of water injection can be controlled at 608-628 m^3 and the average pressure at 8.15-8.27 MPa, and both of them remain basically unchanged. It indicates that Inhi-MPE can retard effectively scaling rate of CaSO4, and ensure the stability of waterflooding quantity and the stableness of injection pressure. By this way, the scaling problem of water injection pipeline can be solved.