Research and application of key technologies for geothermal well drilling in complex strata of Ngari， Xizang

Abstract:

During the drilling of geothermal wells in the Langjiu Geothermal Field in Ngari， Xizang， multiple challenges were encountered such as fractured and collapsed strata， early water blowouts/gush， difficulties in maintaining pressure balance with mud wall protection while drilling， high difficulty in temporary water shutoff with intermediate casing， frequent scaling and malfunction of ram BOP， and inadequate safety protection for personnel at the wellhead. By developing and applying the wellhead blowout preventer diversion device， the dual-hanging water-shutoff device for intermediate casing， and the wellhead valve replacement device for the high-temperature wells， the above difficulties have been effectively addressed. It not only ensures the completion and production of geothermal water from shallow aquifers but also enables drilling through deep geothermal layers， achieving multi-layered geothermal water production with a single borehole.