Rigless Conductor Piling Using Threaded Tubulars - A Strategy to Sustain Oil Production in Onshore Niger Delta

Abstract

Onshore Producing wells in proximity to new cellar slots are required to be shut-in during rigless conductor piling operations using welded conductors. The project objective is to design a novel technology system that can safely makeup and drive threaded conductors without using a drilling rig, thus preventing welding operations (hot works) and production deferment. A multi-disciplinary approach of drilling, safety and structural engineering was implemented during the planning phase. System integration test (SIT) was carried out between the drive sub, piling hammer and conductor. Anticollision analysis was carried out to prevent collision issues with producing wells. Conductor pipe specification was defined to withstand piling loads. A two-staged support frame was designed and fabricated for conductor centralization. Conventional tubular running equipment was combined with piling equipment to make-up and drive threaded conductor pipes. Conductor verticality was achieved using two cranes positioned perpendicularly, working in-tandem and personnel coordinated with intrinsically safe radio devices. The use of this hybrid technology ensured that three slots were successfully piled without welding operations or shutting-in producing oil wells, saving a total of 21,000 bbls ($1.89m @ $90/bbl). Case studies of previous rigless conventional piling operations using welded conductors were compared with the slots piled using the novel rigless hybrid technology. The new approach is safer and more efficient with utmost benefits in sustaining hydrocarbon production in existing locations with live wells close to the new slots. The most significant new finding is that it was possible to make up and drive threaded conductors safely onshore without using a drilling rig, thereby eliminating welding (hot) works.