注水井疏水降压增注液体系的研究与应用

Research and application of hydrophobic reducing pressure and increasing injection liquid system of injection well

关键词:  疏水降压增注  低伤害酸液  硫酸盐垢解除剂  纳米疏水材料  高压欠注井 

Key words:  hydrophobic reducing-pressure and increasing-injection liquid system  low harm acid liquid  sulfate scale release agent  hydrophobic nanometer material  insufficient water injection wells in high pressure

摘要:

为解决长庆油田Y19区块注水井普遍存在的长期高压欠注和措施有效期短的问题,通过开展岩石矿物成分、储层敏感性、地层流体与注入水的配伍性等分析实验,找出了引起注水井高压欠注的主要因素,分别是储层敏感性、注入水引起的润湿反转及化学结垢堵塞。对此,室内研发出一套由低伤害酸液、硫酸盐垢解除剂、纳米疏水材料段塞组成的疏水降压增注液体系。该体系能够有效解除化学结垢堵塞,改善岩石表面润湿性,降低水驱毛管阻力,从根本上解决了引起注水井高压欠注的主要矛盾。已完成的2口现场试验井均达到配注要求,且注入压力下降均超过2 MPa,累计增注8 077 m³,较常规措施有效期延长4个月以上,取得了较好的应用效果,同时也为低渗透油田降压增注作业提供了一种有效的技术手段。 

Abstract:

In order to solve the problems of insufficient water of injection wells with long-term high pressure and short validity period in Changqing Oilfield Y19 block, the lab analysis tests of rock mineral composition, reservoir sensitivity, compatibility of formation fluid and water injection were carried out. The main factors causing insufficient water of injection wells with high pressure were found, these were wettability reversal, fouling blocking and sensitivity of reservoir. In this regard, a set of hydrophobic antihypertensive liquid system consisting of low harm acid liquid, sulfate scale release agent, hydrophobic nanomaterial slug was developed in laboratory. The liquid system could effectively remove chemical fouling blocking, improve the wettability of rock surface and reduce water flooding capillary resistance.Thus the main contradiction caused by insufficient water injection under high pressure of injection wells was fundamentally solved. Two wells completed field test both reach the injection distribution requirements, the injection pressure drop was over 2 MPa, the total increasing injection amount was 8 077 m³, and the period of validity extended more than 4 months compared with conventional measure. The application has achieved a good effect, and provided effective technical means for reducing pressure and increasing injection operation of low permeability oilfield.