A Diagnostic Evaluation of Refracturing Techniques

Abstract

The Barnett Shale continues to offer vast opportunities for refracturing operations. This study covers diagnostic data and case histories of refracturing in the Barnett Shale. Job design and completion techniques are evaluated throughout the project. Candidate selection planys an important role in the overall success of a refracturing program. Wells are grouped by area and original completion design. Completion diagnostics are utilized to test and optimize a variety of refracturing techniques. These techniques include bullhead treatment with and without diverter, various types of diversion, and mechanical isolation. The evaluation of the refracturing program will be broken up into two parts. Bullhead refracturing techniques will be evaluated for new and existing perforation coverage as well as overall lateral coverage. The second part of the paper will evaluate mechanical isolation techniques. These techniques include the installation of a liner with and without isolation on the annulus. A plug and perf treatment is then performed through the newly installed liner. In addition to the optimization through the use of completion diagnostics, the wells are evaluated based on production analysis. This study will compare the overall economics to the method deployed. Twenty-nine horizontal wells are included in this study with some form of diagnostics utilized during the frac. Accessing new rock shows a correlation with incremental reserves as expected. Diversion is evaluated with economic projects on bullhead operations. However, the diversion is not always effective at opening up new perforations and stimulating the well effectively. This study provides data that is utilized to develop best practices for refracturing in the Barnett Shale that can be applied directly to additional basins. In addition to the direct applicability of this work, the methodology utilized to test and optimize diversion can be applied not only to refracturing operations, but also to new well completions.

Advancement in Hydraulic Fracturing for Improved Oil Recovery

“…Near-wellbore diversion is commonly used to ensure a uniform fluid and proppant distribution (particulate diversion, perforation sealing, and mechanical isolation [67]). The Barnett Shale has seen the application of multiple refracturing techniques, including bullhead treatment with and without diverter, various types of diversion, and mechanical isolation [68]. In Daqing Oilfield, refracturing has been employed to address the declining output of tight reservoirs.…”