High Angle HPHT Wells

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe Kristin field is the most extreme HPHT field in Norway with a reservoir pressure of 911 bar and a temperature of 175°C. This gives an equivalent pore pressure of 1.96 sg. With additional safety margin, trip margin and riser margin, it requires mud weight up to 2.07 sg to balance the pore pressure. Combining very high mud weight, high temperature, sub sea operation, gas reservoir and high inclination create a formidable challenge to tools, equipment, procedures and personnel. In October 2004 Kristin finished drilling the first high angle sub sea gas producer in the world under such HPHT conditions. The positive pressure test of the 7" liner marked the successful completion of the drilling phase. The achievement on Kristin introduces a new term in to the oil and gas industry. HAHPHT wells, high angle high pressure high temperature wells. The well R-3 H was drilled 4 m short of 6000 m with an inclination of 75° without any well control incidents. Drilling of the well was completed in 82 days, 2 days ahead of schedule. This paper will highlight some of the challenges and experiences of drilling HAHPHT subsea wells. As this paper is written Kristin has finished drilling of 4 high angle HPHT wells and 2 low angle wells.