具有绿色环保自降解特性的地热井碱激发泡沫暂堵水泥的设计及其制备研究

钻井过程中的漏失不仅增加地热钻井成本，而且可能损害热储甚至造成“干井”给地热能勘探开发带来巨大风险。本项目拟研究可自降解碱激发地聚物泡沫暂堵水泥，利用钻探过程中和完井后地热井温度等条件的改变，控制泡沫水泥性能，使其在钻井过程中具有较高的强度和较低的渗透性，起护壁堵漏作用；完井后自降解，为地热流体提供流动通道。研究内容包括：1）自降解聚合物在地热井环境温度下的降解机理和降解产物及其对水泥性能的影响规律以及改性技术；2）高炉矿渣、煤灰和地热硅结垢物等工业副产品在碱激发条件下合成地聚物水泥的机理以及对聚合物降解的影响规律；3）具有多孔陶瓷特性能的泡沫水泥制备机理和在地热环境下发泡剂和稳泡剂以及可降解聚合物等对泡沫水泥性能的影响，并利用化学改性技术调节气-液-固界面特性，调控泡沫水泥的连通性，改善水泥性能；4）根据上述研究成果设计制备地热井可降解泡沫暂堵水泥并对其进行综合评价和验证。

Lost circulation not only increases the drill cost of geothermal wells, but also damages the reservoir, causing ‘dry well’, which is taken as the biggest risk for geothermal exploitation. This project intends to research the self-degradable alkali-activated temporary sealing foam cement, the properties of which might be adjusted and controlled according to the elevated temperature, with which stabilization of the wellbore could be secured for its high strength and low permeability during drilling process, while good permeable flow paths for geothermal brine production could be achieved through its self-degradation after completion. The research work would be focused on the following aspects: 1) degradation and modification mechanism of biodegradable polymers in the cement system; 2) polymerization and hydration mechanism of geo-polymers prepared with blast furnace slag, fly ash, chaff ash, geothermal silica scaling objects of the industrial and agricultural by-products in alkali activation conditions; 3) preparation of porous ceramic foamed cement foam under geothermal conditions; 4) chemical modification, treatment of interfacial properties of gas-liquid-solid and the connectivity of aphrons, evaluation and validation.