水玻璃凝胶堵剂的制备及在注水开发油藏中的应用

Preparation and Application of Silicate Gel Plugging Agent in Water-flooding Reservoir

针对冀东油田中深层注水开发油藏存在注入水沿平面单向突进、吸水剖面差异大、注采调控难度大等问题,用水玻璃、网络保水剂和延迟活化剂制备了水玻璃凝胶堵剂,分析了水玻璃凝胶堵剂的成胶原理,研究了该堵剂的注入性与封堵性能,并在冀东油田开展了现场应用。结果表明,由水玻璃、延迟活化剂和网络保水剂(质量比为5∶1∶0.2)制备的水玻璃凝胶堵剂注入性和封堵性良好,对中渗和低渗填砂管的封堵率分别为93.5%和97.3%;堵剂选择性较好,优先进入高渗透层进行封堵,堵剂突破后低渗储层的分流率由29.8%增至85.2%,高渗储层的分流率由70.2%降至14.8%。包裹硅酸凝胶、硅酸盐沉淀的大分子交联网状结构提高了水凝胶的成胶强度。水玻璃凝胶堵剂在冀东油田现场应用6口井,增油降水效果明显,平均单井注水启动压力上升4.67 MPa,吸水剖面得到改善,注入水波及体积增加,对应8口油井见效,累计增油4314 t。

There were some problems in mid-deep water-flooding reservoir of Jidong oilfield,such as injection water forward one-way,big difference of water injection profile,and the difficulty of injection production adjustment. So silicate gel plugging agent was developed using silicate,water retention agent and activator. The gelling principle of silicate gel plugging agent was analyzed,the injectivity and plugging performance were studied,and the field application was carried out in Jidong oilfield. The results showed that when the mass ratio of silicate,water retention agent and activator was 5∶1∶0.2,the plugging rate of plugging agent to media and low permeability sand pipes was 93.5% and 97.3% respectively,showing good injectivity and plugging ability.The plugging agent had good injection selectivity which preferred to plug higher permeability layer. The diversion rate of low permeability sand pipe increased from 29.8% to 85.2% and that of high permeability sand pipe decreased from 70.2% to 14.8%. The gel strength was improved by the cross-linked network structure coated with silicate gel and silicate precipitate. After the silicate gel plugging agent was applied in 6 wells on site,the average water injection pressure increased 4.67 MPa,the water injection profile was improved and water injection volume was increased. There were 8 corresponding wells which had an obvious effect of increasing oil production and decreasing water cut and the cumulative oil increment was 4314 t.