Externally Catalyzed Epoxy for Sand Control

Abstract

In this improved method of consolidating sand there are three principal steps: preflushing with a permeability-enhancing organic chemical, injecting a resin solution, and overflushing the resin solution with an oil containing a catalyst that is both immiscible with and more viscous than the resin solution. Introduction Plastic consolidation techniques have been used to Plastic consolidation techniques have been used to control sand production for more than a quarter of a century. Because of chemical cost and interval coverage requirements, the use of these systems is restricted to short productive intervals, usually 20 ft or less. Where applicable, however, consolidation offers several advantages over alternative approaches to sand control. One advantage is that plastics are easy to apply since they require only the injection of liquid chemicals into the formation. This is important in all wells to which a process might be applied, but it is particularly important in slim, deviated holes typical of many offshore wells and in upper zones of multiple completions where mechanical devices often are intractable and difficult to install. A second advantage of consolidation is that the wellbore remains unobstructed. This preserves the full flow capacity of the perforations and the tubing and also means that nothing is left in the well that can complicate subsequent workover operations. The relatively large volume and large peripheral area resulting from a consolidation treatment offer advantages not found in mechanical techniques.During the last 10 to 15 years, a number of new and improved plastic systems have been developed and tested. Several of these are in routine use today and sand consolidation has become an accepted sand control practice, especially along the U. S. Gulf Coast. The systems commonly available today, however, do not provide a completely satisfactory solution to the sand problem. The two primary reasons for this are that the treatments are seldom permanent - most of the initially successful jobs fail before the reservoir is depleted - and all systems cause some reduction in the permeability of the consolidated region. Although neither of these drawbacks has severely limited the use of plastics in the past, both are becoming more important considerations as higher production rates place greater stress on the consolidated sand and place greater stress on the consolidated sand and impose greater economic penalty for treatment failure or impaired well productivity.The externally catalyzed process described in this paper reduces the effect of both limitations mentioned paper reduces the effect of both limitations mentioned above. Laboratory tests have shown that this system is capable of consolidating sand with no loss in permeability. Furthermore, the resulting consolidations permeability. Furthermore, the resulting consolidations have high initial strength and resistance-to-aging properties that are superior to other systems we have properties that are superior to other systems we have tested. Approximately 50 field tests of the process have been conducted in the last 2 years. The results of these field tests have confirmed our laboratory findings. With few exceptions, the wells treated in this manner have produced at high rates and have experienced longer treatment lifetimes than wells treated with other commonly used systems. EPR Epoxy The externally catalyzed epoxy process described here basically involves three steps: application of a preflush chemical, use of a resin solution, and preflush chemical, use of a resin solution, and follow-up with a catalyst oil. JPT P. 589