Gravel Pack Cleaning: A New Solution

Abstract

Abstract A large number of fields worldwide have sand production problems and a common solution is a gravel pack (GP) completion. Over time this GP can become plugged with production fines as well as solids that may precipitate out of the produced fluids. As the GP plugs, it creates a larger restriction to flow and the production rate will decline. At some point the operator will decide the production rates are no longer acceptable and intervention is required. As a result, the GP completion will either be pulled from the well or be cleaned in-situ. Previous in-situ cleaning processes involved treatment fluids bull headed into the well or placed by coiled tubing, to dissolve GP plugging damage. This paper describes a new method for cleaning a GP in-situ. The process involves a rotating jetting head to create specific pressure pulsations combined with angled nozzles to create a "circulation current" within the GP. These circulation currents are localised and result in a temporary increase in GP permeability ensuring that treatment fluid will invade the GP only in the area immediately adjacent to the tool. This new process is significantly more efficient at unplugging the GP than previous methods and treatment fluids can more effectively reach areas of the completion such as the perforation tunnels and drill-in fluid filter cake damage. This process also includes managing the jet impact pressure to ensure that fragmentation damage of the GP proppant does not occur. The paper will report results of laboratory tests using existing wash methods compared with the new technique and demonstrate the differences in; treatment fluid placement efficiency, fines removal efficiency and damage caused to the GP proppant.