Abstract
Proppant produced during production often causes damage to downhole pumps and surface equipment. In addition to restricting production rate, frequent workovers are often required to remove proppant or sand infill, thus resulting in costly downtime. To help resolve these proppant production problems, solvent-based curable resins have often been used in remedial treatments of affected wells. These resin systems have been applied in intervals of less than 100 ft. For longer intervals, ineffective diversion of solvent-based resins and their potential interaction with water in the wellbore can prevent them from providing complete coverage over the entire perforated interval.
A novel water-based consolidation system has been successfully developed to overcome safety, fluid compatibility, and placement issues, which most current solvent-based resins encounter during their field applications. This paper presents the results of laboratory testing and field applications and discusses the challenges, lessons learned, treatment procedures, and recommendations in applying this newly developed resin system.
The curable consolidation component is emulsified to form a water-external emulsion so that the active material can be delivered in a brine-based solution. Extensive laboratory testing has indicated that optimum concentration of coating is necessary to maximize the bonding between proppant grains. This allows the proppant pack to withstand high production flow rates and to overcome the effects of stress cycling while minimizing any reduction in its permeability. Results from field trials showed that this aqueous-based consolidation system successfully treated both proppant and formation sand in near-wellbore regions to lock them in place without damaging production flow paths. In these field tests, intervals in excess of 300 ft were treated effectively with a bullhead squeeze using consolidation-treatment fluids that were foamed to a quality of 50 or higher to aid in diverting treatment fluids and extending treatment volume.
One major advantage of this aqueous-based system is its simplicity in field treatments without the concern of fluid incompatibility between fluid stages during their placement because of its benign behavior. The new system uses small treatment volumes to impart excellent consolidation properties while, at the same time, retaining formation permeability. This makes the treatment system simple to deploy and economically viable.
