昆2加深井超高温聚胺有机盐钻井液技术

近年来，柴达木盆地加强了向纵深勘探的力度，高温、超高温成为考验钻井液的关键因素。通过开展超高温稳定性能、流变性能以及超高温条件下的滤失性控制等方面的技术攻关，在聚胺有机盐钻井液基础上，对超高温钻井液体系降滤失剂和抑制剂进行优选，形成昆2加深井超高温聚胺有机盐钻井液的最终配方。该配方钻井液在老化48 h后，高温高压滤失量保持在10 mL以内。昆2加深井段岩性以泥岩为主，岩石水敏强，易膨胀分散，通过无机盐KCl与有机盐以及聚胺的有效结合，极大地提高了钻井液抑制性能，泥岩岩心膨胀量降低率达93.33%。该井在基岩段6934~6995 m井段多次发生漏失，通过在井浆中复配5%惰性架桥封堵剂ZYD+3%超细碳酸钙QS-4+2%胶质粒子，以交联的模式封堵漏失层，分级多次操作，使基岩风化带的地层承压能力达到了2.00 g/cm3的当量密度，为超深井段的井壁失稳和井漏的预防治理发挥了关键作用。顺利完成了柴达木盆地第一超高温超深井昆2加深井的钻探保障任务。 

Ultra-high Temperature Polyamine Organic Salt Drilling Fluid for Deepened Well Kun-2

As the wells drilled in the Qaidam Basin are becoming deeper and deeper lately, much more attention has been drawn to the performance of high temperature and ultra-high temperature drilling fluids. Laboratory studies have been conducted on the stability, rheology and filtration properties of drilling fluids at ultra-high temperatures. A polyamine organic salt drilling fluid previously formulated was optimized with newly selected high temperature filter loss reducer and shale inhibitor to form a drilling fluid for use in drilling the ultra-high temperature deepened well Kun-2. After aging for 42 h, this new organic salt drilling fluid had HTHP filter loss less than 10 mL. The lithology of the formations penetrated by the well Kun-2 is mainly mudstones and is water sensitive and easy to swell and disperse. Combination of KCl, organic salt and polyamine greatly improved the performance of the drilling fluid, and the percent expansion of mudstone core tested in the drilling fluid was reduced by 93.33%. During drilling, mud losses took place between 6934 m and 6995 m. By adding 5% inert bridging agent ZYD, 3% ultra-fine calcium carbonate QS-4 and 2% gel particles into the drilling fluid, the weathered rock matrix was strengthened after several times of treatment to withstand the pressure exerted by a column of mud of 2.0 g/cm3, a key role in stabilizing the borehole wall and controlling mud losses in an ultra-deep well. With the use of this polyamine organic salt drilling fluid, the deepest well Kun-2 with the highest bottom-hole temperature in Qaidam Basin, was drilled successfully.