High Angle Sidetrack Applications of Motorized Rotary Steerable Drilling Systems in Complex Horizontal Wells

Abstract

Abstract A challenging cirmcumstance unfolded in the initial lateral 6 1/8-in section of a sidetrack horizontal well drilled for Kuwait Oil Company in North Kuwait. The original well was drilled by a competitor whose BHA became stuck in the "Mauddud A" layer formation at 9892 ft MD / 7509.5 ft TVD, in the initial part of the lateral section. Several failed fishing attempts resulted in a cement plug, burying the RSS and LWD BHA with radioactive sources. Kuwait Oil requested Baker Hughes' expertise to sidetrak and drill the 6 1/8-in lateral section. The distance from the 7"-in liner shoe to the top of the fish was only 74ft. The top of fish is 7509.07 ft TVD, and the bottom of fish 7523 ft TVD. A motorized rotary steerable system (RSS) was proposed by Baker Hughes to perform the sidetrack. No cement was encountered during the first 28 ft of sidetrack. The motorized RSS BHA successfully sidetracked the well, passing the top of fish by 2 ft, marking the first high angle sidetrack completion with RSS and modular motor BHA. After completing the sidetrack, the motorized RSS BHA was pulled out of hole (POOH) to pick up the LWD tools. The lateral section was drilled to well total depth (TD) with the BHA, and included the distance to bed boundary and triple combination logging while drilling (LWD) tools. Reservoir navigation services (RNS) (Geosteering) was utilized to geosteer the lateral section of the Mauddud B reservoir section. The proactive geosteering services enabled 97.7 % of reservoir contact to remain in the target reservoir (of the Mauddud B formation) despite encountering two faults with 10ft TVD upthrow. The well was TD at 12832 ft MD / 7552.9 TVD-RT, near the bottom of the Mauddud B formation.