干热岩抗高温环保水基钻井液体系

传统能源储量日益减少，干热岩类新型能源的开发变得尤为重要。然而干热岩井底温度较高、井深较深且存在造斜井段、其周边有自然保护区，对钻井液的高温稳定性、环保性有着严格的要求。如果能设计高效的抗高温钻井液体系，将会对干热岩的开发起到事半功倍的效果。因此对30余种处理剂进行常规性能测试与热滚老化实验，通过控制变量、正交实验等方法，根据干热岩特征对钻井液的组分、含量进行设计筛选，得到一套干热岩抗高温钻井液体系，并对该体系在不同温度、密度、老化时长的条件下进行抗温性能测试。实验结果表明，该钻井液体系在240 ℃高温下依然有较好的高温稳定性；该体系采用聚合物类处理剂，其内部形成的网架结构稳定，不易被高温破坏，同时针对地层特点而设计的泥饼薄且有韧性、对井壁侵蚀性较小；除此之外还采用了白色无污染原材料，不含磺化、油基成分，性能环保，对周边环境污染性小。 

An Environmentally Friendly High Temperature Water Based Drilling Fluid for Hot-Dry-Rock Well Drilling

As the traditional energy reserves are declining, the development of new energy, such as hot-dry-rock, is becoming more and more popular. Hot-dry-rock wells have high bottom hole temperatures and are very deep, and sometimes are drilled directionally. Furthermore, some hot-dry-rock wells are located in an area surrounded by nature reserves. These factors impose strict requirements on the high temperature stability and environmental friendliness of the drilling fluid used to the hot-dry-rock well. If an efficient high-temperature drilling fluid can be formulated, it will do more with less in developing hot-dry-rock energy. In laboratory experiment, regular performance test and hot-rolling aging test were performed on more than 30 additives. The component and concentration of a drilling fluid for hot-dry-rock well drilling were designed and screened through variable control and orthogonal test methods. As a result, a high temperature drilling fluid for hot-dry-rock well drilling was developed. Laboratory experiment shows that this drilling fluid has good stability at temperatures as high as 240 °C. Polymers used in this drilling fluid form a stable network structure which is not easy to be destroyed by high temperature. The mud cakes formed by the drilling fluid is thin and tough, and is able to protect the borehole wall from being eroded. Some white non-polluting materials free of sulfonated and oil-based ingredients were also used in formulating the drilling fluid, they are environmentally friendly and pose very little pollution to the environment.