Gulf of Suez Horizontal Drilling Challenges
Authors: Holt Charles A. , Binegar Jim , Mansour Sayed 
Published: December 2007

Since 1993, Gulf of Suez Petroleum Company (GUPCO) has drilled seven horizontal wells in four different fields of the Gulf of Suez. Each well or field has posed a unique set of challenges to accomplish the desired goals of the well. Drilling and completion challenges have included zonal isolation, slim hole, unique casing designs, depleted reservoirs, deep & hot reservoirs that equal or exceed equipment limitations, hook or designer type trajectories, torque and drag limitations, and hole cleaning issues. This paper includes a review of each well describing the challenges and solutions unique to each well or field. The evolution or learning process used to solve problems will be discussed, including the application of turbines unique compromise drill pipe completion in the GS 365 lateral well, and the application of diesel as a lateral drilling fluid. Equipment and procedures utilized to solve problems unique to GOS drilling will be discussed in the paper. The paper includes comparisons of GUPCO's lateral challenges versus Amoco Production Company and Industry wells.

Introduction

GUPCO's first horizontal well was drilled in the July Field, July 62–69 ST1. This well was drilled to recover attic oil trapped below two approaching faults. Zonal isolation between the sand and shale sequences perpendicular to the faults was key to success of the well. The second well, Badri A-16, required penetrating and isolating the Kareem gas cap from the horizontal section through the oil bearing zones. The GS 365 horizontal well was GUPCO's first medium radius horizontal well. A pre-perforated liner with external casing packer (ECP) isolation was designed for GS 365, however after the drill string became stuck a drill pipe completion was utilized to salvage the well. The four horizontal wells in the Sidki Field proved the most challenging. The target Nubia formation is deep and hot in the Sidki field and drilling a 6-1/2" horizontal wellbore at 10800 ft TVD in temperatures of 295 degree F static at the end of a hook or designer wellpath proved challenging.

July Field Horizontal Well

The first horizontal well drilled by GUPCO in the GOS was July 62–69 ST1. This well was a 1200 ft 87 degree lateral section paralleling a fault penetrating the attic oil trapped against the fault. The key challenge in this well was zonal isolation between the various sands exposed by the lateral section (Figure #1). In order to improve the isolation along the lateral section, a 5" liner was planned for the 8-1/2" horizontal section. Ridge centralizers were placed on every casing joint along the lateral and a rotating liner hanger was used to improve the cement displacement.

The well was drilled in conjunction with the service company as an incentive project. Service company personnel were in the GUPCO Ras Shukheir office assisting in the decision making along the way. The simple incentive contract was based on a drilling time curve, where the service company would get a bonus if the curve was beat or lose revenue if the curve was exceeded. Both the bonus and penalty were limited to 10 days maximum. Although the well was drilled trouble free for the most part, 47 days were required to total depth, 9 days more that projected.

An oil base mud system was utilized to drill the 8-1/2" lateral section. Hole cleaning and cuttings transport were monitored by comparing the actual hole drag and torque with prediction from the drag and torque model. When deviations between the predicted and actual were observed a back reaming trip was conducted. Low/high viscosity sweeps were routinely pumped, yielding results the majority of the time. Minimizing or eliminating a cuttings bed was imperative in this well, since zonal isolation was key to success of the well.

After reaching total depth, the 5" liner and rotating liner hanger were run into place. The job appeared to have gone as planned, rotating the liner through out the job.

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