The ability to intervene in extreme extended reach wells using conventional technology has lagged 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 40,600ft was achieved in flowing condition.

Extending the distance that a tool-string 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 maximize 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 25,000 ft. 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 50% well capacity. 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.

Successfully reaching the toe section of an extreme extended reach well and consequently proving the accuracy of the prediction models for both rod and tractor performance demonstrates the ability to gather production data from previously unreachable areas of high value wells. For intervention engineers, precise planning becomes possible in even the longest of extended reach assets. Drilling of such extended reach wells from artificial islands reduces well counts, accelerate development and increase oil recovery y 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 operator to acquire production logs and perform well services effectively to maintain the life cycle of extended reach wells inaccessible with conventional solutions.

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