Drilling fluid technology of deep salt-gypsum beds of Tahe Oilfield

Drillpipe sticking and casing damage are caused during drilling through deep salt-gypsum beds and have negative effect on safety drilling.Based on the comprehensive analysis on the mineral constituent and the physical and chemical features of the deep salt-gypsum beds of Tahe Oilfield,this paper describes the main cause of borehole instability,providing theoretical basis for selecting optimum drilling fluid system.What’s more,it probes into the drilling fluid system and field maintenance technology proper to the section,proposing the scheme for saturated salt water drilling fluid technology and applying it in well T913,TK827,and TK1106.Application results show that complicated degree of downhole is lowered considerably,the deep well drilling circles is shortened dramatically,and good economic results are achieved,based on applying the new drilling fluid technology.