延长油田注水井多元复合酸解堵技术

齐春民; 夏宇; 唐善法; 王哲; 李鑫; 赵连吉

doi:10.3969/j.issn.1007-3426.2025.06.011

延长油田注水井多元复合酸解堵技术

Multiple compound acid blocking removal technology for water injection wells in Yanchang Oilfield

摘要

摘要:
目的延长油田某地区存在注水井结垢堵塞严重、高压、欠注等问题，亟需采取有效措施明确其堵塞成因，提供解堵技术。
方法采用灼烧−失量法对堵塞物有机/无机类型及含量进行了探究，通过元素测试（elemental analyzor, EA）、X射线衍射（X-ray diffraction, XRD）、傅里叶变换红外光谱（Fourier transform infrared spectroscopy, FTIR）测试及电感耦合等离子体测试（inductively coupled plasma, ICP）明晰了堵塞物有机/无机组成成分，研究了一种适用于该地区注水井的多元复合酸化解堵体系（reservoir-tailored universal stimulation fluid, RTUS）。
结果注水井堵塞物无机成分主要为少量CaCO₃和Fe（OH）₃，有机成分为聚丙烯酰胺与聚丙烯酸等的降解产物。腐生菌的滋生、水质配伍性欠佳及水体有机组分难处理，导致了注水井环空区域的管道堵塞。以盐酸作主酸、柠檬酸复合有机酸体系作辅酸的RTUS，对不同井堵塞物的1 h溶蚀率≥85%，12 h溶蚀率≥90%。现场应用结果表明：RTUS体系解堵效果较好，试注清水一次成功，平均工作压力≤1.5 MPa，解堵后60 天内注水平均工作压力2 MPa。
结论 RTUS解堵体系基本解决了延长油田该地区的结垢堵塞和高压、欠注问题，为该地区降压增注作业提供了可行方案。

Abstract:
Objective There exist the problems in one area of Yanchang Oilfield, such as serious scaling, high pressure and insufficient injection of water injection wells. It is urgent to take effective measures to clarify the causes of blocking and propose blocking removal technologies.
Method The organic/inorganic types and contents of the blockages were investigated by the combustion-weight loss method, and the organic/inorganic compositions of the blockages were clarified by elemental analyzor (EA), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) testing and inductively coupled plasma (ICP) testing, so that a multiple compound acid blocking removal system namely reservoir-tailored universal stimulation fluid (RTUS), suitable for water injection wells in this area was developed.
Result The inorganic compositions of the blockages in the water injection wells were small amounts of CaCO₃ and Fe(OH)₃, and organic compositions were degradation products of polyacrylamide and polyacrylic acid. The growth of saprophytic bacteria, the poor water quality compatibility and the difficulty in treating the organic compositions of the water body all contribute to the pipeline blocking in the annular region of the injection wells. The RTUS system, with hydrochloric acid as the main acid and citric acid composite organic acid as the auxiliary acid, had a 1 h-dissolution rate of more than 85% and a 12 h-dissolution rate of more than 90% for different well blockages. The results of field application showed that the RTUS system had a good effect of blocking removal, the test injection of water is successful, the average working pressure was not more than 1.5 MPa, and the average working pressure of water injection was 2 MPa within 60 days after blocking ramoval.
Conclusion The RTUS blocking removal system basically solves the problems of scaling, high pressure and insufficient injection in the area of Yanchang Oilfield, and it provides feasible solutions for the operation of pressure reduction and injection increase in this area.

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