To access the reservoir in a large Saudi Arabian development field, the operator is required to drill an intermediate 5,000 ft to 6,000 ft directional hole section with dogleg severity (DLS) varying from 2.5°/100 ft to 3°/100 ft. The commonly drilled 12¼-in. borehole crosses several interbedded formations comprised of limestone, shale and sands, and it is associated to a variety of hole problems, which present repeatedly in the offset wells. The main objective for the operator was to mitigate the problematic by defining alternative and suited drilling technologies. Among them, Saudi Aramco found that the recent developments in the directional casing while drilling (DCwD) technology may well provide an effective method for diminishing the associated nonproductive time (NPT).
The drilling engineering team conducted an extensive evaluation of the problems across this section, including wellbore stability, water flow, and loss of circulation; tight hole/stuck pipe incidents, severe bit/stabilizer wear while drilling abrasive sands. After a promising technical and engineering evaluation, followed by a detailed risk assessment aiming to determine the potential of the application, the selected well was planned and executed using the DCwD service.
This paper outlines the process carried out during all stages through the final deployment of the first 9⅝-in. DCwD application in Saudi Arabia, and how it successfully aided in achieving the goals by reducing the impact of some of the problems experienced while drilling the same section in previous wells in the field. Likewise, the information provided will serve as a starting point for the design and construction of subsequent wells leading to further improvement in drilling performance. Best practices and lessons learned from this implementation are expected to become a model and the know-how transferred to other areas where comparable drilling events occur.
The technological benefits have been recognized by the operator and this application reestablished DCwD as a viable technology to address a number of challenges common in many of the Saudi Arabian oil and gas fields.