CwD – Enables for Successful Extended Reach Drilling. First Time with 9 5/8" Casing at High Angle

Abstract

State of the art technology provided by Casing-drilling Services has successfully delivered an Extended Reach Drilling well (ERD) under one of the most challenging scenarios. Challenge consisted on drilling the well from a triple-splitter wellhead in a Malaysian offshore field, navigate through a highly collision-prone platform, pass through a zone prone to loss circulation, and ultimately set up the casing as deep as possible to allow producing from the objective zones, which is located at adjacent fault block. To enable this long ERD well, the surface casing must be set as deep as possible for higher chance of success in reaching reservoir objectives. The triple-splitter wellhead design with 13 3/8-in. conduit constrained the casing design to smaller casing design. The engineering framework and the drilling techniques had to be adapted to overcome the expected challenges. Analysis of the solutions developed during design and execution, the outcome of the solutions, and the learnings from the project have been documented. The directional casing-drilling technique enables the surface hole to be drilled as deep as possible with a dynamic kill-while-drilling with a diverter in the event of any kick or shallow gas hazard. A feasibility study was performed during which all the key hazards from anti-collision in this highly congested platform, offset well losses, and well control issues were collected and mapped. After numerous engagements with industry expert/SMEs from both the operator and service providers, casing-drilling technology was selected based on lowest risk and highest chance of success. Strong collaboration at early planning stages was vital in this scenario where all the existing casing-drilling techniques and operational practices were challenged. The execution result was highly successful. This was the first application of directional casing-drilling from a triple-splitter wellhead with polycrystalline diamond compact (PDC) bit. The PDC bit has allowed significant increase in weight on bit (WOB) and subsequently an increase in rate of penetration (ROP), which is comparable to conventional drilling. In addition, the casing-drilling service eliminates the need to drill a pilot hole where dynamic kill is not possible. This case study provides guidelines, from the planning work to successful field execution, that can be applied for ERD well design.