Selection of Thru Tubing Screen for Sustained Sand Control Beyond a Year - Methodology and Optimization

Abstract Sand production can cause significant damage to well and facilities, such as erosion of flowlines, choke valves, filling up of downstream equipment causing loss of production. This poses a significant threat to the integrity of the surface flowlines and facilities and eventually can lead to Loss of Containment (LOC), which must be avoided. In Shell, sand prediction and management is a mandated Design Engineering Practice (DEP) that must be carried out as part of the life cycle well design 1. The well that is subject of this study was designed with an internal cased hole gravel pack to avoid sand production to surface. However, the gravel pack system failed pre-maturely. Lessons learnt from the failure include review of the operating envelope to include the onset of the water production and increase in gas-oil ratio (GOR), improved open-up procedures and surveillance. Further, to safely recover production from the well with minimal risk of LOC, a thru-tubing screen solution was selected, which was designed according to specific well conditions to retain sand downhole. The selected screen dimensions, number of screen joints, deployment methodology, operating envelope, etc., will be discussed in this paper. This paper provides a standard approach for remedial thru-tubing sand control. The success and longevity of the thru-tubing screen solution depends on understanding the maximum allowable impact velocity, base pipe velocity etc. so that the right screen OD is selected. Open-up procedures and surveillance are the key to prevent sand related erosion. This will be further detailed in this paper.