Abstract
This paper describes a monomer system for formation consolidation in deepwater applications. In deepwater wells, shallow zones may have pore pressures close to fracturing pressures. In these situations, lost circulation or flowing zones can be difficult to control and can lead to a complete loss of the well.
Hydroperoxide and azo initiators were used for polymerizing solutions of 2-hydroxyethyl acrylate in aqueous solutions of sea salt, sodium chloride (NaCl), calcium chloride (CaCl2), calcium bromide (CaBr2), and zinc bromide (ZnBr2) with densities from 8.6 to 17.5 lbm/gal. These monomer solutions undergo controlled polymerizations in the formation to yield stiff plugs that can withstand high differential pressures. A similar monomer system has been used for water shutoff applications, but had never been formulated in heavy brines or used in the cool temperatures (50° to 60°F) typical of the shallow water-flow zones. Using a high-density consolidation fluid would be advantageous in shallow water-flow zones. This fluid could be spotted over the problem zone and allowed to flow into the zone because of the hydrostatic pressure. This fluid would allow the treatments to be used in wells where high-pressure injection into the formation is not an option. Before this work, no high-density fluids were available for these applications.
Various data are shown describing the system's development, including gel-time curves and compressive strengths of consolidated sandpacks. Factors affecting the performance and application of the system are discussed.
