Improved reservoir Access Through Refracture Treatments in Tight gas Sand and Gas Shales

Project funded by Research Partnership to Secure Energy for America(RPSEA)

Executive Summary

The primary challenge facing gas producers in unconventional gas plays is the rapid depletion rate of new wells and their relatively high cost. Rapid decline rates require that many new wells be drilled just to maintain production. To address these concerns, this proposal aims at developing methods for improving reservoir access through existing wellbores so as to minimize drilling and completion costs. This can be accomplished by reducing the number of wellbores drilled by suitably fracturing and re-fracturing both vertical and horizontal wells.

Re-fracture treatments are widely applied in gas shales and tight gas sands but with highly variable success rates. Current methods for candidate well selection are primarily based on statistical data available from past treatments in the play. Re-fracture designs do not take into account changes due to near-wellbore and reservoir stresses and pre-existing proppant packs which can have a big influence on the design of re-fracture treatments. This proposal aims at developing a systematic methodology for providing an operator the following key deliverables:

• A well defined methodology for candidate well selection based on poro-elastic models and analysis of field data.
• Recommendations and charts for the time window most suitable for re-fracturing, for a range of reservoir types, reservoir properties and production profiles.
• Application of re-fracture treatments in horizontal and deviated wellbores
• Re-fracture treatment designs utilizing novel fluids, proppants and injection strategies

This will be accomplished through field application of newly developed geo-mechanical models, proppant placement strategies, and better re-fracture designs based on novel fluids and proppants.

Download presentation [1.66MB PDF] given at Denver, Colorado on 4/14/09 for current information/updated status for the project.

Participants involved in the project: