Evaluation and Improvement of Gravel Pack Treatments Using Advanced Downhole Pressure Analysis

Abstract

Openhole gravel packing (OHGP) is emerging as one of the primary completion techniques in horizontal wells with sanding tendencies. As the experience level for this technique increases, OHGP applications are extending to more challenging environments, including longer intervals. Because many of these jobs are performed in offshore and deep water environments where the cost of failure is substantial, a thorough knowledge of all aspects of treatment design, execution, and evaluation is required. While many OHGPs have been performed, the current understanding of both treatment success and failure is limited due to either a lack of sufficient data (such as bottomhole pressure and temperature) or experience in its evaluation. This paper introduces data analysis techniques that can be used for a more detailed insight into a variety of downhole events, including packing mechanisms, fluid changes, and system frictions. The pressure analysis technique presented isolates sections of the flow path and identifies these events within the system for accurate treatment analysis. The combination of this technique and volumetric and material balance calculations ensures a detailed quantitative approach to gravel pack data analysis. The background theory and its application are discussed through a detailed case study of a well in the Poinsettia field, offshore Trinidad, in which downhole gauge data was used to identify and quantitatively analyze the final pack integrity. The analysis technique was able to confirm complete coverage of the screens as well as the packing mechanism by which the gravel was placed. This approach to gravel pack evaluation maximizes the value of downhole memory gauge data, yielding an improvement in the knowledge of downhole processes and facilitating the continuous improvement of OHGP job design and execution.