Abstract

One of the highest profile extended reach drilling (ERD) oil projects in the world is presently operated by Saudi Aramco. It is being developed with a large number of horizontal ERD wells targeting a carbonate reservoir; classified according to the well objectives as producers or injectors. The wells are being drilled from land locations, artificial islands and offshore platforms which increase the complexity and challenges of the project. The production and well delivery requirements for the development phase were planned with very ambitious targets. Therefore, multiple drilling and completions technologies have continuously been pursued to achieve the planned schedule.

During the past years, the drilling team planned to take this project to the next level by drilling and completing the longest horizontal ERD well in Saudi Arabia (M-1) to a total depth (TD) of 37,042 ft MD with an open hole completion of 10,002 ft. To achieve this and to push the drilling envelope to that extent, many drilling challenges were expected and new approaches, procedures and technologies were deployed to overcome them.

The main challenges were related to torque and drag limitations for drillpipe and casing runs, losses and wellbore stability considerations, hole cleaning and equivalent circulating density (ECD) management for stuck pipe prevention, drilling dynamics in harsh drilling environment, logging data transmission at deep intervals of the well and pushing the limit of drilling performance and equipment reliability. To overcome them, considerable well design changes were introduced, along with customized procedures and new technologies to ensure the safe and efficient delivery of this well. First, the well design was optimized and changed from a standard design to a deepened casing design, to cover unstable formations. Second, the drill string design loads were simulated through comprehensive torque and drag modeling to determine the components specifications and to develop safe running procedures. Third, well specific ERD hole cleaning procedures, ECD management guidelines and tripping roadmaps were implemented to deliver optimum hole condition and minimize stuck pipe risks. Finally, multiple drilling technologies, including rotary steerable systems, telemetry tools, sidetracking equipment and mud additives, were introduced to realiably deliver the well objectives.

The optimization changes in the well design, procedures, practices and drilling technologies have resulted in delivering a number of records which include: drilling the longest well in Saudi Arabia safely and efficiently, installing the world's deepest 7-in. solid liner, achieving the world record for the deepest 6 1/8-in. lateral section and the longest 6 1/8-in. section for the project; and successfully running and setting the world's deepest 7-in. cased hole whipstock. These records are considered a step change for Saudi Aramco drilling operations and a new milestone for the ERD drilling industry.

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