US 11,143,001 B2Granted

Optimal screened subsurface well design

OwnerCarl E. Kellerinventor

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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.

Claims15

Dependent claims

A method for providing a stable borehole in a subsurface geologic formation, to permit ground water evaluations, comprising the steps of:

(a) driving a drill casing into a subsurface of the ground to form a borehole having a bottom;
(b) removing material from an interior of the drill casing;
(c) lowering a screened casing into the interior of the drill casing;
(d) depositing a first sand fill at the bottom of the borehole and in an annulus between the drill casing and the screened casing;
(e) installing a flexible liner along an interior of the screened casing to seal temporarily the inside of the screened casing;
(f) withdrawing the drill casing upward a first incremental distance;
(g) emplacing a first layer of sealing material upon the first sand fill and within the annulus between the drill casing and the screened casing;
(h) depositing another sand fill in the annulus and upon an underlying layer of sealing material;
(i) withdrawing the drill casing upward another incremental distance;
(j) emplacing another layer of sealing material upon the another sand fill and within the annulus;
and
(k) repeating steps (h)-(j) a number of iterations thereby filling at least a portion of the annulus between the drill casing and the screened casing with alternating layers of sand fill and sealing material.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/895,182Filed 8 Jun 2020 · us provisional application
Priority: 6 Jun 2019
Published: US 2020/0386082 A110 Dec 2020
Granted: 12 Oct 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

E21B 43/025
Subsoil filtering: consolidation of loose sand or the like round the wells without excessively decreasing the permeability thereof
E21B 7/20
Special methods or apparatus for drilling: driving or forcing casings or pipes into boreholes, e.g. sinking; Simultaneously drilling and casing…
E21B 33/138
Methods or devices for cementing, for plugging holes, crevices or the like: plastering the borehole wall; Injecting into the formation
E21B 43/08
Subsoil filtering: screens or liners