CT-Deployed Multipurpose Nozzle for Effective Sand-Cleanout and Acidizing Operations in a Single Trip: Injector Wells Case Histories

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWells requiring combined sand clean out and acidizing operations have been routinely treated using BHA's containing different nozzles in multiple trip operations. This is especially true for sanded-up completions. The normal scenario would be to use a standard wash nozzle for both acidizing/sand cleanout operations or to use a switchable nozzle for the sand clean-out, POOH and then run a rotating jetting nozzle (for acidizing). However, the former scenario would not be optimal because standard washing nozzles are not effective against filter cakes / scale and the latter alternative might be in some situations an over-kill leading to really expensive operations. This paper describes the use of a specialized nozzle that generates a 'vortex' or a fast swirling mass of fluid in the completion tubulars/open hole. Jet velocities and rotational speeds commonly exceed 460 ft/sec and 8000 rpm, respectively. Because of a specially designed internal flow guide, this nozzle entrains debris and also provides improved jet coherence and projection compared to standard jetting nozzles. This dual feature of the nozzle made it particularly attractive for use in combined sand clean out/acidizing operations of sanded up injectors. This nozzle also has no moving parts or rubber seals; therefore, the commingling fluid phases would not affects the efficiency of the tool.These injectors are vertical completions with architecture ranging from perforated intervals to standalone screens. The sediments consist of a mixture of organic deposition, fine siliceous material and carbonate scales. This paper analyzes the improved post injectivity and compares results using this nozzle to those using a wash nozzle/rotating nozzle combination on the basis of cost, operational efficiency/simplicity and technical effectiveness. These results suggest that some non-aggressive scales can also be treated using this nozzle as an alternative to a rotating jetting system leading to reduction in well intervention cost through a single trip approach.