油井结垢预测及防垢技术

Prediction of Scaling Tendency and Scale Control Method for Oilwells

关键词:  油田垢  碳酸钙  结垢预测  酸洗  防垢剂  挤注

Key words:  oilfield scale  calcium carbonate  scaling tendency  acid-cleaning  scale inhibitor  squeeze treatment

摘要:

我国东部老油田在注水开发后期都出现了较为严重的结垢现象。现场垢样分析和结垢趋势理论预测表明碳酸钙是主要垢型。频繁的酸化及检泵作业,易对地层、油套管和地面设施造成伤害,使用挤注防垢技术是一种新的尝试。本文描述了防垢剂挤注技术的室内实验、挤注方案设计及现场应用研究。在胜利油田和江苏油田的三个目标区块的现场试验表明,井下挤注防垢技术是一种可行的现场施工工艺,操作过程简单,适用地层条件范围广,可用于高温、高钙、低孔低渗的苛刻地层条件;与酸洗除垢的不同结合方式对挤注防垢效果无明显影响,实际作业时可根据不同的目标要求选择相应的结合方式;从源头防垢,有效期长,可显著提高油田的经济效益。

Abstract:

Serious scale occurs in many mature fields in Eastern China after several years of water injection,which has a great impact on the production.Field sample analysis and theoretical prediction of scaling tendency show that the scale mainly contains calcium carbonate.Up to now,frequent acid treatments and pump overhaul homeworks have caused severe damage to production casing,tubing and surface facilities.The use of scale inhibitors via downhole squeeze treatment can be an effective and economic solution.In this paper,experimental study,squeeze treatment design and field trials were described particularly.Good performances observed from three target areas in Shengli and Jiangsu oilfields confirmed that downhole squeeze treatment is a workable and simple method for scale control,and it can be applied in high temperature,high calcium content,low-porosity and low-permeability formation;the different combined method with acid-cleaning has no significant influence on scale inhibition effect;long squeeze life and good benefits have been obtained.