Drillability Beyond Pressure: BP's Gulf of Mexico experience

Blangy, Jean-Pierre¹, Martin Albertin², David Greeley¹, Paul Mitchell¹, Johnathan Bellow¹, Charlie Jay³, Graham Vinson¹, Johnston Paul¹, Ray Wydrinski¹, Shira Paulson¹, Bruce Wagner¹ (1) BP, Houston, TX (2) BP, Houston, (3) BP, Sunbury, United Kingdom

Business Needs. Exploration in the Gulf of Mexico Deep Water has now moved to complex subsalt areas, with the majority of our current portfolio residing subsalt. Subsalt areas remain a relatively unexplored Frontier, due to the complexity of salt bodies and our inability to “see” clearly through salt “lenses”. In response to drilling problems encountered upon exiting salt, BP developed an integrated approach to the Drillability of subsalt wells.

Technical Developments. The multi-faceted approach involves

(A) An evaluation of Drillability based on

-1- Front End Loading with 3D-Seismic

-2- Basin Modeling and Petroleum Systems

-3- Petrophysics-Offset data

-4- Look-Ahead VSP in Salt

-5- Real Time monitoring & Feedback to the rig via MWD

(B) A database of Analogs

(C) Drilling technology, Well design and Operating Best Practices

Results and Materiality. The Drillability program kicked-off in 2001 and incorporates over one dozen wells in the period 2001-2006. Throughout this time, well performance has improved dramatically and that portion of Geology-related NPT has been reduced significantly. Problems encountered upon exiting salt, which used to constitute up to 1/3 of all NPT, have been virtually eliminated.

Challenges and Future Directions. Given the complex nature of salt and the variable Quality of the data available, the Drillability workflow requires the involvement of Experts and the Integration of Disciplines. Customized solutions are needed on a well-by-well basis. Key products include the formalization of a comprehensive Subsalt Drilling Risk Analysis, the creation of Composite Drilling Risk maps and 3D visualization capabilities. Based on its track record, BP will continue to apply Drillability techniques, where appropriate Business and Technical conditions exist.