A new phenolic resin system has been developed for proppant consolidation when fracturing low temperature wells. Before the development of this new resin system, which was in response to a global industry need, external chemical activators were necessary to achieve sufficient bond strength of the resin coated sand pack (when treating wells with bottom-hole temperatures less than 140°F). This new low-temperature cure system develops superior proppant pack bond strength and requires no external activation at temperatures as low as 100°F.Eliminating the need for external activators not only decreases the complexity of the fracturing treatment, but also contributes to the saving of time, money, and decreases the need for chemical transportation and the associated potential hazards.However, the lower operating temperature limit of this resin chemistry can be extended even further with the addition of an external chemical activator.
The paper will discuss product performance data that was generated to document the effectiveness of this technology at simulated downhole conditions. Results from the initial field trials utilizing the new Low Temperature Resin Coated Curable Proppant (LTRCCP) in various shallow wells in the Permian Basin will also be presented. Field trial data resulted from thirty-nine treatments that were performed on a total of twenty-two wells, in nine different producing horizons, spread over four different fields in Southeast New Mexico and West Texas. The Information presented describes formation properties, treatment designs, post fracturing production response and lessons learned.
Introduction
Curable, phenolic resin coated proppants (RCPs) have been successfully used in the prevention of proppant flowback and prop pack rearrangement for more thantwenty-five years [1,2,3,4].Loss of fracture connectivity to the wellbore and the resultant loss of productivity is important in lower temperature applications as well as the more notable higher temperature applications [2,3,5].At lower temperatures (<140°F), various external chemical activators have been used for the last twenty years to help the resin coating develop higher grain-to-grain bond strength[1,2,6].However, in many field applications it is common practice to flow wells back immediately following the completion of the hydraulic fracturing operation.In this situation, external chemical activators can be run with curable RCPs even at temperatures up to 160ºF.Without the use of an external chemical activator, and depending on the proppant mesh size and thus the number of contact points, the useful and measurable proppant pack consolidation strength development of the conventional curable phenolic resin proppants in water at lower temperatures(<140°F) can take ½ to 5 days as the temperature approaches 100°F [1,6].
Alberta Province in Canada, the Permian Basin in West Texas/New Mexico, Alaska, and the Northeast U.S.A., along with Western Siberia in Russia are areas where large amounts of RCPs can be used at lower temperatures.The combination of shallow depths, and waterflooding or CO2 flooding of mature oil producing reservoirs, can provide challenges to develop the necessary RCP pack strength without the aid of an external chemical activator.
