Technology of double casing tubes & a binary cycle system for hole cleaning for CBM multi-branch horizontal wells

Numerical investigation of a double-circulation system for cuttings transport in CBM well drilling using a CFD-DEM coupled model

“…One of these changes is the use of a double-circulation system (DCS) for CBM well drilling, in which the gas is replaced with viscous liquid. DCSs have been applied to CBM well drilling in the Qinshui basin in China, and encouraging results have been obtained (Yang et al, 2015(Yang et al, , 2017. However, currently there are few studies on the working mechanism of DCSs in relation to cuttings transport, so the relevant numerical simulations are carried out in the present work, which is expected to provide some guidance on and perhaps improvements to the further application of DCSs.…”

Old well sidetracking selection standards: Sulige low-permeability gas field, China

“…With the application of various drilling tools and instruments (Tybero et al 1996;Qiu and Miska 1999;Pineda et al 2013;Kong et al 2017), the technology has been developed quickly, and it has obtained more obvious economic benefits than drilling a new vertical well. At present, sidetracking technology is very mature, not only the horizontal wells with various curvature radii can be completed in the sidetracking hole, but also the multi-branch wells can be sidetracked in a main wellbore (Yang et al 2017;Yue et al 2018).…”