Completions using inflow control devices (ICDs) help provide balanced production inflow, delay water and gas breakthrough, and extend the productive life of the well. For fluid circulation, displacement, and wash down, an ICD completion typically utilizes a washpipe or inner string to provide flow to the bottom of the screens. However, the use of a washpipe increases operational time, operational risks, and costs. Through the use of dissolvable materials, a washpipe-free ICD completion has been developed for fluid circulation and wellbore displacement.
The dissolution properties of multiple dissolvable materials were experimentally measured with field fluid samples used during running in hole (RIH) and displacement. The degradation rate was characterized at downhole temperatures in terms of both mass loss and volume loss versus time. The dissolvable material was incorporated into a nozzle ICD to help prevent flow between the inner and outer annulus of the tubing. The pressure-holding performance of the ICD with the dissolvable material was measured by means of small-scale testing for pressure integrity, followed by full-scale testing, simulating particular fluid circulation and displacement sequence characteristic of both a Middle East and West Africa application.
Laboratory testing was used to determine dissolution rates of multiple materials at representative temperatures and in various fluids. Small-scale testing demonstrated that the dissolvable material provided pressure sealing integrity within the ICD. The dissolution rate of the dissolvable material within the plugged ICD behaved as predicted in the laboratory tests when subjected to circulation and displacement with the fluids representative of the field application. The washpipe-free ICD completion performance tests indicated that the dissolvable material provides a means for circulation and displacement while maintaining pressure integrity necessary for the successful deployment of the lower completion. The capability to run washpipe-free ICD completions helps reduce operational time and costs, and upon dissolution of the dissolvable plugs, delay gas and water breakthrough through the use of ICDs.