改善低渗油藏二氧化碳气驱油效果的耐温泡沫凝胶体系的构建

Preparation of Temperature Resistant Foam Gel System for Improving CO2 Gas Flooding Effect in Low Permeability Reservoir

杨子浩 罗智忆 林梅钦 吕其超 李晓晨

YANG Zihao，LUO Zhiyi，LIN Meiqin，LYU Qichao，LI Xiaochen

二氧化碳气驱对低渗油藏的开发与利用具有明显的优势，但是在驱油过程中极易产生气窜，造成二氧化碳过早突破含油带。为了抑制气窜，提升气驱效果，在聚丙烯酰胺溶液中加入起泡剂和交联剂等，制得泡沫凝胶封堵体系。通过测定凝胶强度、黏度、泡沫体积、泡沫半衰期等评价了其耐温性能，借助光学显微镜和扫描电镜分析其耐温机理，并通过人造低渗裂缝型岩心评价其封堵性能。结果表明，在100℃、矿化度10 g/L的条件下，配方为0.3%聚丙烯酰胺、0.245%酚类交联剂、0.0348%醛类助交联剂、3%稳泡剂黄原胶、0.075%起泡剂非离子表面活性剂和0.4%除氧剂硫脲的泡沫凝胶的稳定性较好，半衰期可达10 d。泡沫凝胶的微观形貌表明，液膜中的聚合物在高温下发生聚合反应形成凝胶相，网状凝胶液膜结构使得泡沫凝胶具有优异的耐温性能。泡沫凝胶可在低渗裂缝型岩心形成强度较高的封堵，在开度为0.1 mm的人造低渗裂缝型岩心中形成封堵后的气驱突破压力达到1020 kPa，具有封堵气窜通道，控制气窜的能力。

The carbon dioxide gas flooding has obvious advantages in the development and utilization of low permeability reservoir，but it is easy to produce gas channeling in the process of oil displacement，which causes carbon dioxide to break through the oil-bearing area prematurely. In order to control gas channeling and improve the effect of gas flooding，a foam gel plugging system was prepared by adding foaming agent and crosslinking agent in polyacrylamide solution. Its temperature resistance was evaluated by measuring gel strength，viscosity，foam volume and half-life of foam. Optical microscope and scanning electron microscope were used to study its temperature resistance mechanism，and its plugging performance was evaluated through artificial low permeability fractured core. The results showed that under the condition of 100℃ and 10 g/L salinity，the stability of the foam gel with 0.3% polyacrylamide，0.245% phenolic crosslinking agent，0.0348% aldehydes assistant crosslinking agent，3% xanthan gum foam stabilizer，0.075% non-ionic surfactant foaming agent，and 0.4% deoxidizer thiourea was excellent，and the half-life of the gel was 10 days. The morphology of the foam gel showed that the polymer in the liquid film polymerized at high temperature to form the gel phase，and the structure of the network gel liquid membrane made the foam gel have excellent temperature resistance.The foam gel could form high-strength plugs in low permeability fracture cores，and the gas breakthrough pressure could reach 1020 kPa in the artificial low permeability fractured core with an opening of 0.1 mm. The foam gel had the ability to plug and control gas channeling.

10.19346/j.cnki.1000-4092.2020.01.016