Abstract
The ability to intervene in extreme extended reach wells using conventional technology has lagged behind the ability to drill and complete them. This paper intends to describe how the physical properties inherent in carbon composite materials provide a means of deploying logging tools into such a well in combination with a high-performance tractor, and to document a case study where a total depth of 40,600 feet (ft) was achieved against a production flow of 6,500 barrels of oil per day (BOPD).
Extending the distance that a toolstring may be conveyed into a horizontal well by means of tractoring devices is well established. The medium for the conveyance becomes the critical component of the system to both maximise the ultimate depth achievable and to ensure safe retrieval. Low friction, low weight and high strength of the rod all combine to reduce required tractor loading and ensure safe recovery. The rod rigidity confers exceptional depth accuracy and removes the potential of tool-lift at high production rates, allowing logging under conditions that are truly representative of commercial well operation.
A well that was drilled to a depth in excess of 40,000ft measured depth, with a trajectory designed to maximise the contact between wellbore and reservoir, was completed with a limited entry liner. A total of 37 compartments with lengths between 700ft and 900ft were separated with swell packer assemblies along a horizontal section of 25,000ft. Critical information about the production flow, including toe/heel balance, had been unavailable because of the limitations imposed by the available intervention methods.
The intervention was designed to fully exploit the physical properties of the carbon composite rod in combination with the most efficient in-well controlled tractoring technology available, and aimed to reach deeper than 40,000ft. Simulations based on previous experience showed that this depth would be achievable with the tractor chosen and further that this could be achieved even with the well flowing at rates of over 5,000BOPD. This meant that deferred production could be minimised along with waiting periods for flow stabilisation.
The intervention was successfully concluded in a single operation, gathering production data from as deep as 40,600ft. Performance of both rod and tractor aligned with planning simulations with significant margin, indicating further performance enhancements in reach being readily achievable.
Drilling of such extended reach wells from existing islands will reduce well counts, accelerate development and increase oil recovery by unlocking reserves from the tight rock and areas that are currently unreachable from existing islands and wellhead platforms.
Technology solutions like carbon composite rod and high-performance tractors enable the operators to acquire production logs & perform well services effectively to maintain the life cycle of extended reach wells inaccessible with conventional solutions.
