青海共和盆地干热岩GR1井超高温固井水泥浆技术

固井是保证干热岩全生命周期井筒质量的关键环节。通过研究共和盆地干热岩地质特征和赋存条件，提出了干热岩固井的主要技术难点。针对干热岩高温固井问题，研制出了高温缓凝剂BCR-320L，优选抗高温降滤失剂BXF-200L（AF），探索了不同硅粉加量下水泥石强度的衰退机理，形成了干热岩超高温水泥浆体系。实验结果表明，该水泥浆可以满足循环温度为200℃的固井要求，水泥浆稠化时间可调，具有良好的流变性能，在200℃下强度不衰退，72 h抗压强度可达44.1MPa。该水泥浆在青海共和干热岩GR1井中成功应用，现场固井施工顺利，裸眼段固井质量优质，为后续干热岩固井的施工提供了一定的借鉴。 

Ultra-high Temperature Cement Slurry for Cementing Well GR1 Penetrating Hot Dry Rock Formations in Gonghe Basin,Qinghai

The job quality of well cementing is the key factor affecting the borehole quality of a well penetrating hot dry rock formations. The major technical difficulties in cementing the wells penetrating hot dry rock formations in the Gonghe Basin in Qinghai were determined by studying the geological characteristics and the conditions for the hot dry rock to exist. An ultra-high temperature cement slurry for cementing the wells was formulated with a high temperature retarder BCR-320L and a high temperature filter loss reducer BXF-200L (AF), based on the investigation of strength decline mechanisms of the set cement with different concentrations of silica powder. Laboratory experimental results showed that the cement slurry can be used to cement wells at circulation temperature of 200℃. The cement slurry has good rheology and adjustable thickening time. The strength of the set cement does not decline at 200℃, and the compressive strength of the cement slurry after aging 72 h is 44.1 MPa. This cement slurry has been successfully used in cementing the well GR1 which penetrated hot dry rock formations in the Gonghe Basin in Qinghai. The quality of the cementing job was excellent. This cementing technology has provided a reference for subsequent hot dry rock well cementing.