Underground Gas Storage (UGS) Screen (PKhG)

Well-known sand screen designs used in UGS wells are currently not any different to those used for production wells. However the operation cycle of a UGS well is different; in a UGS well although during the pumping phase when the gas is being extracted out, the screen performs its intended function but during gas injection phase (i.e. the reverse operation) when no screening is required, the gas will still pass through the well screen causing additional and unnecessary wear of its wire wrap and thus rapid loss of the screen efficiency.

Because of the above difference in operation of the screen in a UGS well, our design of filter for UGS wells is different to others. In our unique design, a special device (a ‘switch’) is incorporated under the screen body which can be used to allow the gas injection to be carried out directly into a reservoir i.e. ‘bypassing’ the screen.

Additionally not only the highest manufacturing technology and material specification is used in our design to achieve high resistance to wear but also our design allows the reservoir fluid to be screened along the entire length of the base pipe (i.e. entire length of the screen unit rather than just a section of it which is the norm with other manufacturers).

Further the screen wrap wire used is special profiled wire which is wrapped and welded on the sleeve. The size and pitch of the wrap wire can be specified based on the flow conditions.

Technical Specifications:

Production casing diameter, mm    
146; 168
Screen outside diameter, mm 
73; 89; 114; 146
Screen length, mm  1690
Wire wrap porosity min, %  7
Ratio of wire wrapped length to the screen overall length, min 
0,75
Wire wrap nominal pitch, mm 
0,2; 0,3; 0,5; 0,7; 1,0
Packer outside diameter max, mm    
118; 140 
Outside diameter of screen removal tool, mm 
89; 102