Reliable and Effective Downhole Cleaning System for Debris and Junk Removal

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWellbore debris is responsible for many of the problems and much of the extra costs associated with producing wells, especially in extreme water depths and highly deviated holes. Even a small piece of debris at the right place at the wrong time can jeopardize well production. For this reason, debris management has become a chief concern for oil and gas producers. Considering rig rates and completion equipment costs, debris removal is moving into the realm of risk management.A clean wellbore is not only a prerequisite for trouble-free well testing and completion; it also helps ensure optimum production for the life of the well. Debris left in the wellbore can ruin a complex, multi-million dollar completion; it can prevent a completion from reaching total depth. And chances are, it will never reach an optimum production level.These issues are pushing the industry to create reliable, efficient systems for quickly ridding wellbores of harmful debris and larger pieces of junk. This paper describes a vectored annular cleaning system (VACS) that can be used alone or in conjunction with any of an assortment of improved casing scrapers, brush tools, downhole magnet subs, downhole filter tools and junk catchers to optimize the efficiencies and economics of debris removal and save trips. This paper will focus on the use of the vectored annular cleaning system to collect and remove debris from areas of the wellbore that traditionally are problematic; i.e., above liner tops, where casing size changes, areas with a loss of annular velocity, and wells with little to no circulation. Case histories from the Gulf of Mexico, North Sea and other areas of the world will demonstrate how this technology has reduced problems of debris removal while saving rig time by eliminating trips.

Sand Cleanouts With Coiled Tubing: Choice of Process, Tools and Fluids

“…Several cleanout techniques have been developed over the years, these include stationary circulation, wiper tripping (1,2,(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) , reverse circulation (19)(20)(21)(22) , sand vacuuming technology (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)36,37) , and venturi sand/junk bailers (4,22,(38)(39)(40) .…”

“…Flow loop tests under real downhole conditions (38) show that the sand-carrying capacity will increase with increasing foam quality for polymer-stabilised foam. Adding viscosifiers, such as waterbased polymers, will increase the fluid sand-carrying capacity and the foam stability.…”

“…96 119 124 125 142 157 161 161 176 195 199 200 212 242 252 254 254 254 273 289 292 293 293 292 283 269 254 240 225 211 198 185 172 161 149 137 127 Temperature, ˚F Viscosity @ 100 sec-1, cP Sand/Junk Bailers (3,21,(38)(39)(40) Over the years different types of sand bailers have been developed for use with jointed pipe, wireline and CT for the removal of large and/or heavy particles and debris. By far the commonest type of bailer used for coiled tubing is the venturi junk basket (4,22,38) . This tool is not dependent on hole size to work, so, for example, a 2 1 / 8 -in.…”

Assessment of the Technical Level of Magnetic Fishing Tools

“…In addition, a lot of metal cuttings remain in the wells after the milling operations as well as sidetracking [3]. Haughton and Connell [4] suggested that circulation of drilling mud do not transport larger metal debris to the surface. These cuttings accompany the drilling process and may cause the failure of the rock destruction tool.…”