World-class rig ‘Krechet’ spudded its first well in Odoptu field in Sakhalin 1 Project recently. Mr. P K Rao, Director (Operations), ONGC Videsh congratulated the team for successful commissioning of yet another world class rig in the project, which is capable of drilling world record ERD wells. He acknowledged that the dedicated rig for the field will not only improve the management of the reserves from an operational perspective but also help control costs and execution strategy for future phases.
Odoptu Stage 2 is a phased expansion of the existing Sakhalin Odoptu development, in shallow reservoir zones. The new land rig was commissioned in early 2017 and christened as ‘Krechet”- meaning Gyrfalcon, the largest of the falcon species. The rig has capability to drill longer horizontal sections and has superior mobility due to smaller modules, which can be easily dismantled, transported and assembled at site. This feature is useful as the drilling in stage 2 development of Odoptu is planned from two sites (NWS & SWS) around 9 Km apart.
The drilling company, which designed and built all the 3 powerful rigs of the project (Yastreb, Orlan and Berkut), was awarded the contract for designing the rig. The rig was fabricated in the Keppel AmFEL yard Brownsville, Texas. The overall construction and final load out completed in May 2016. The modules of the rig travelled around 46,000 nautical miles on five barges and reached the temporary offloading facility, specifically built to receive the modules of stage 2 development of the field, around 13 Km from the Odoptu North site in around 3m water depth. All the modules were navigated in Piltun bay via fleet of 6 shallow draft tugs with WinFrog navigation system to make precise transits across sandbar at the mouth of Piltun bay and Piltun bay channel. The rig modules were transported to the well site assembled and commissioned in Jan 2017. The rig spud first well on 28th Feb 2017 after completing conductor driving for first 4 wells. The rig is scheduled to drill 4 development wells including 2 producers. The first oil from the stage 2 development of the field is expected in 3Q 2017 and the field is expected to reach its peak production of 65 KBOPD in 2018.
The Krechet’s key design components include a fully enclosed drilling rig, automated pipe barn, and double-wall, 2-inch insulation. The enclosed rig and pipe barn allow the rig crew to perform drilling operations in temperatures of around 21 C (70 F) year around. The rig’s top drive has load capacity of 1250 tons, 3,000-hp draw works and torque at continuous operation of 142kNMat 130 rpm. To handle the extremely long wells, the Krechet also features four 7,500-psi mud pumps, 6020 bbl liquid-mud storage capacity and six generators. The ERD wells are batch drilled for efficiency. This drilling method requires moving the rig from well to well over a 100-meter (328-foot) track without being rigged down. Consequently, the rig is designed so that the rig and support equipment and facilities, including the utility modules, mud pits and pipe barn, could be moved hydraulically from one wellhead to the next.
Odoptu Stage 2 includes drilling 32 wells at the North and South Wellsite. The North Wellsite and South Wellsite wells will be drilled using extended reach drilling technology (ERD) with measured depths of up to 13300 meters and total vertical depth (TVD) of approximately 2000 meters. All oil production well completions will be fitted with downhole side pocket mandrels complete with casing pressure operated gas lift valves. The wells to be equipped with stand-alone screens for sand control. Annular isolation for various zones will be achieved through the use of swell packers. For commingled production from zones having various permeabilities, inflow control devices (ICDs) as well as surface-controlled downhole valves will be used to ensure optimum recovery of reserves along the length of the wellbore within the field.
