Practice and understanding of sidetracking horizontal drilling in old wells in Sulige Gas Field, NW China

ZHANG Jinwu,WANG Guoyong,HE Kai,YE Chenglin

Table 1 Statistics on the drilling rate of sidetracking horizontal wells.

Serial number Well Sidetracking year Drilling cycle/d Horizontal section length/m Sandstone drilling ratio/% Effective reservoir drilling ratio/% Produced effective gas layer thickness/m Gas saturation/% Controlled reserves/ 104 m3 Target layer 1 Su10-aCH 2011 61 528 89.2 53.6 6.4 48.5 3 180 P2h86 2 Su10-bCH 2012 92 700 53.7 39.4 6.0 58.9 3 652 P2h86 3 Su10-cCH 2015 37 654 100.0 38.4 11.9 48.6 5 070 P2h85 4 Su10-dCH 2015 47 600 100.0 82.8 8.7 50.1 4 765 P2h85 5 Su53-aCH 2016 36 800 16.5 16.5 11.2 49.5 4 578 P1S17 6 Su53-bCH 2016 21 800 100.0 72.6 8.3 75.9 9 169 P2h86 7 Su53-cCH 2016 33 800 98.3 90.6 8.7 40.6 5 129 P2h86 8 Su53-dCH 2016 52 769 86.2 23.4 8.7 53.1 3 397 P1S17 9 Su53-eCH 2016 62 558 72.0 65.1 10.9 64.8 6 404 P2h85 10 Su53-fCH 2017 34 668 97.8 92.1 11.5 71.3 11 943 P2h85 11 Su53-gCH 2017 60 593 97.8 76.1 12.3 57.8 9 254 P1S17 12 Su53-hCH 2017 49 800 98.8 87.4 10.4 58.3 10 716 P2h86 Average 49 689 84.2 61.5 9.6 56.5 6 438