Controlled Pressure Drilling and the Application in High-temperature Geothermal Exploration

Abstract:

Abstract: Controlled Pressure Drilling (CPD) involves three subsets, Managed Pressure Drilling (MPD), Underbalanced Drilling(UBD) and Air Drilling(AD). CPD could be used to decrease non drilling time and mitigate drilling hazards, increase rate of penetration (ROP), prevent lost of circulation, eliminate sticking, protect reservoir with low pressure and improve productivity. Geothermal wells are of characteristics of high temperature, hard rock, fractured formation and low pore pressure along with likely high pressure of shallow formation. It is proved that CPD could increase ROP, prevent lost of circulation and improve productivity. This paper introduces CPD technology and its application in geothermal energy exploration and development.