Application of Concentric Coiled-Tubing and Well-Vacuuming Tool With Chemical Sand-Consolidation Resins for Controlling Sand Production in Wells With Damaged Screens or Slotted Liners: A Rigless Well-Repair Alternative

Abstract

Reservoirs comprised of poorly consolidated sands are generally prone to some level of sand production throughout the life of the well. This sand production creates many challenging problems for the operator such as erosion and/or failure of both down-hole and surface equipment, lower well production due to tubular fill-up and, finally, environmental issues related to the final disposition of the produced solids. All of these problems also have a common denominator: they significantly increase the cost of production for the well's in question.Conventionally, the application of any technique for controlling sand production is recommended as soon as it is known that the problem exists. Among some of the solutions available are 1) sand control by mechanical means using slotted liners and screens combined with conventional gravel packs, 2) prepacked completion screens, 3) lowering the production of the well thereby reducing the draw-down across the formation and 4) chemical sand consolidation (CSC) resin treatments: the latter being the focus of this paper.The principle behind the CSC process is the adherence of sand grains to a liquid resin that, while cross-linking occurs, penetrates and hardens across the porous matrix. The newly create mass of consolidated sand exhibits much higher mechanical strength, able to withstand the drag forces generated by oil production.CSC resins can be injected either when a well is initially completed or during workover operations which are needed to clean a sanded-up well-bore where said sand deposition is the result of failed completion screens or slotted tubulars. In such cases, the CSC resin acts as a plug across the heightened sand producing area and represents an economically viable alternative to complete replacement of the damaged tubulars or, as a worse-case scenario, well replacement. This paper will discuss a combination of technologies where both CCTWV (used to clean the well and detect the sand intrusion points) along with CSC resin technologies were used to successfully repair two wells in the unconsolidated URD-01 reservoir that were producing sand through holes in 5" Slotted Liner and 3-½". pre-packed completion screens.

A Chronological Review of Concentric Coiled Tubing Vacuum Technology: Past, Present and Future

“…The Chemical Sand Consolidation (CSC) technology is used, among other things, to repair failed completion screens or slotted tubulars that allow the well to produce undesired sand (Medina et al 2010). When the liquid resin is injected into the porous matrix, the sand grains adhere to it.…”

“…The CCTVT and CSC resins proved to be a reliable and economical rigless combination of technologies for solving sand production problems in wells with damaged sand control equipment. Details of the operations are presented in Medina et al 2010.…”