Herrenknecht Vertical supplied the first deep drilling rig type TI-350 Slingshot – known as the ”Innovative Hydraulic Rig“ – to China. The rig's high level of automation allows precise and safe drilling to a depth of 6,000 meters with maximized working safety and small crews. With its hydraulic XY stepping system the entire rig can be skidded in two directions to drill multiple wells from a single location.
The most efficient solution for the exploration of shale gas is a so-called multi-well pad, on which the drilling rig moves itself step by step from well to well easily and quickly. Herrenknecht Vertical’s implementation of this idea was the XY stepping system integrated into the ”Innovative Hydraulic Rig“ of the type TI-350 Slingshot delivered to China in 2014. Hydraulic cylinder supports can raise the entire deep drilling rig and move it several meters – forward and backward as well as laterally. Time-consuming and costly rig-down and rig-up procedures are eliminated.
China National Petroleum Corporation (CNPC) placed the order with Herrenknecht Vertical. China's biggest oil and gas producer required a project-specific and customized rig for the exploration of shale gas deposits in the Sichuan province. The exploration and production of natural gas trapped in shale is considered technically challenging. A number of deviated wells at depths of several thousand meters are required in this region.
XY stepping and dedicated training speed up hands-off pad drilling
Thanks to the XY stepping system, the wells could be drilled with an alternating program: the wells were not drilled one after the other, but section by section, eliminating the need for frequent drill pipe and mud changes. Due to the telescopic catwalk in the horizontal pipe rack system, the rack also stayed in place when skidding the rig, as the catwalk transfers the tubulars always to the same hand-over position for the pipe handler. With the technical features of the XY stepping system and telescopic catwalk, the TI-350 Slingshot was the ideal choice for efficient shale gas drilling in depths down to 5,500 meters and more.
Herrenknecht Vertical‘s dedicated training program for the customer's crew and service personnel proved to bear fruit in the project. Experienced on conventional rigs only, the team highly benefited from the initial training and started drilling efficiently with the hydraulic rig right from the first spud-in. Later on, the Herrenknecht Vertical service team conducted additional special training on tripping operations, which benefits drilling particularly at greater depths by speeding up the process. As of autumn 2017, four wells are finished with depths from 5,100 to 5,700 meters (MD). On well 5 and 6 the first two sections have already been drilled, and drilling on the last section of well 5 is ongoing.