Selecting the optimum sand control technique for reservoirs with large vertical thickness and long wellbore lengths through the pay zone is currently a topic of widespread discussion in the industry. The selection is made by comparing the expected productivity of the completion procedure with the cost. The decision is made difficult because some very important reservoir parameters such as permeability, damage, oil properties, and layering sometimes only become known during the completion phase.

This paper gives the overall results of fourteen producing oil wells that were completed in two offshore fields in West Africa using the frac-and-pack sand control technique. The wells had deviations of up to 61°. These wells have moderate production levels (around 2,000 bopd/well) and have multiple layers, spread over 200 to 350 ft gross interval lengths. One aspect of this paper will be to describe the efforts made to quantify the relative costs between various sand control techniques, taking into account such factors as material costs, rig times, and equipment requirements, and how these cost assessments were then weighed against expected completion efficiencies.

When designing the treatments, some important guidelines were also established regarding how to group layers together for a single treatment, how to open the perforations before the frac treatment, how to model fracture growth in these deviated wells with possibly more than one interval perforated, and the actual completion procedure. A review of the different well results is presented with the objective to better understand the impact on the productivity of different factors such as deviation, interval length, completion and sand control practices.

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