Patent ID: 11143001

Abstract:
A method and system for supporting unstable geologic materials surrounding a borehole after the borehole is drilled, while reducing the vertical migration in a sand pack behind a slotted screen in the casing. An annulus is defined between a drill casing and a continuous screened casing. Alternating sand fills and sealing layers are deposed in the annulus along a length of the borehole. The length of the sealed interval between the screened casing and the hole wall is reduced, allowing flow connection between the surrounding geologic formation and the interior of the casing over most of the casing length. The sand pack design between the screen and the borehole wall has a sufficient number of sealed barriers to vertical flow to approximate an ideal sand backpacking, which has a vertical conductivity no greater than that of the formation and a relatively low impedance to horizontal flow through the sand pack.