A New Method of Overbalanced Perforating and Surging of Resin for Sand Control

Summary

Gravel packing of perforations is the conventional method for sand control in the petroleum industry. Case histories of 12 well treatments provide details of a new procedure for high-energy resin placement that controls sand in a formation. The new consolidation method uses an extremely overbalanced pressure surge with liquid resin on perforations. This paper presents the problem, theory, process description, job procedure, and results of resin treatments with perforating or surging with a high-energy overbalanced pressure pulse. Highlights include potential applications. Benefits of the technique include accelerating on-line production and reducing completion rig time spent on controlling sand. The method appears to yield equal or better results than previous conventional gravel-packing techniques.

Introduction

The underbalanced method is the petroleum industry standard for perforating wells requiring sand control. Efforts to prevent the perforating guns from sanding up with for mation sand restrict the amount of underbalanced differential pressure. Sufficient underbalanced pressures for full perforation cleanup is not standard. Perforations that are not cleaned adequately will not readily accept resin during matrix injection.

Operating companies took underbalanced perforating to offshore operations with the introduction of tubing-conveyed perforating guns in 1970. Today, few offshore operators consider overbalanced pressure in wellbores when perforating a well for sand control. Environmental concerns or equipment limitations provide a few cases of overbalanced perforating. In these rare instances, the fluid hydrostatic pressure will slightly exceed reservoir pressure. This reduces fluid invasion from mud or expensive brine water before the gravel-pack procedure.

Until now, the industry has accepted underbalanced perforating and gravel packing as the best way to complete a well for sand control. Oryx Energy Co. began a research project on sand control in wells with gas generators and resin in Oct. 1988. Success with the propellant-gas fracture resin placement method led to extension of the research to include extreme overbalanced perforating with resin in Aug. 1990. The downhole high-energy placement of resin for sand control now challenges the industry's conventional standard of underbalanced perforating and gravel packing for sand control.