Abstract
Abstract
Currently, many of the producers are horizontal wells and a considerable number of them are equipped with smart complex completions. Evaluating the performance of these horizontal producers is critically important for improved reservoir management. Conventional production logging tools cannot meet the challenges of logging horizontal wells, especially in multiphase flow. A new logging tool has been specifically designed to better characterize fluid flow in horizontal wells. Advanced sensors provide better resolution among gas, oil, and water and cover more cross sectional areas of a wellbore for enhanced characterization of multiphase flow regimes. The new tool is also more compact to pass through intervals that have high dog legs.
In this paper we will briefly review the new technologies available today for production logging, with examples of evaluating horizontal wells with barefoot smart completions, diagnosing water entries, flow profiles and fluid break-through. Production flow profiles are also used for identifying geological features such as super permeable zones or fractures. Well performance evaluation shows that the integration of the flow profiles, well performances and all other reservoir data provided improved reservoir characterization and better well production strategies.
Introduction
With technology development, oil producers and water injectors are being drilled horizontally, many multilaterally. These wells maximize borehole contact with the target reservoir in order to achieve the goal of optimizing oil recovery. Vertical wells are drilled only for formation evaluation purposes or for special situations such as infill drilling.
Horizontal wells bring new opportunities as well as challenges for reservoir characterization and management. Since they have maximized reservoir contacts, much more information is provided about reservoir characteristics and reservoir behavior during production or injection. This information is valuable for better understanding, thus managing, the reservoir as a whole.
Monitoring and managing horizontal wells to have optimum production/injection is challenging, especially for multilateral horizontal wells. First of all, it is much more difficult to complete horizontal wells. For example, poor cementing jobs can result in unexpected casing/liner shoe leaks. Second, well intervention operations, such as production logging (PL) and water shutoff, have to be conducted via either a coil tubing unit (CTU) or tractors. CTU's limitation is that it can't reach far. Tractors work the best in cased hole or open holes with reservoir rocks of having high compressional stress. Failures have been reported while tractoring in open holes with soft formations.