GYx地热井钻井液技术

高阳地热田GYx地热井，钻遇新近系及古近系地层较齐全，完钻井深3920 m，是一口三开井，目的层为蓟县系雾迷山组，施工中存在卡钻、漏失、掉块、坍塌及油气的风险。二开施工是钻井液的重点和难点，钻井液采用以大分子包被剂为主的聚合物泥浆及抗高温硅基防塌泥浆，使用耐高温的钻井液材料，按照地层压力控制钻井液密度，使用页岩抑制剂抑制页岩的水化膨胀，严格控制钻井液的失水量，使用润滑剂提高泥浆润滑性；采用四级钻井液固控设备并合理使用；所用钻井液性能良好，解决了施工中存在的风险问题，同时取得了较高的机械钻速。

Drilling fluid technology for geothermal well GYx

Geothermal Well GYx in Gaoyang Geothermal Field was a three-section well with a completion depth of 3920m. Neogene and Paleogene formation was drilled in this well, and the target layer was Wumishan Group of Jixian System. Drilling operations in the formation was difficult due to many problems such as sticking, leakage, chipping, collapsing, and even occurrence of oil and gas layers. Preparation of proper drilling fluids were very critical and difficult, especially for the second section drilling. Polymer mud with the macromolecule coating agent and silica-based anti-collapsed mud with high temperature resistance were adopted for the drilling fluid, and the high temperature-resistant drilling material was used. The density of the drilling fluid was controlled according to the formation pressure. The shale inhibitor was used to prevent shale hydration and swelling, and to control the water loss of the drilling fluid as well. The mud lubricity was improved by adding some lubricating agent. The four stage solid control equipment was used to clean the drilling fluid. By taking these measures, the drilling fluid adopted in Well GYx provided good performance, which had eliminated the drilling risks; meanwhile the penetration rate was greatly improved.