Method for continuous downhole cooling of high-temperature drilling fluid

Patent metadata

Field	Value
Publication number	US-11236584-B2
Application number	US-202017123123-A
Country	US
Kind code	B2
Filing date	Dec 16, 2020
Priority date	Aug 11, 2020
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

The invention discloses a circulating system and a method for continuous downhole cooling of high-temperature drilling fluid. The circulating system includes a cooling water tank, a cooling water injection pump, a plurality of U-shaped pipes, a liquid nitrogen cooling tank, a spiral pipe, a cooling water return pump and a return pipeline. The U-shaped pipe is fixed in an unsealed bond cement gap between outer and inner casings, and two ends are respectively connected with output end of the cooling water injection pump and the spiral pipe. The spiral pipe is disposed in the liquid nitrogen cooling tank; input and output ends of the cooling water return pump are respectively connected with the spiral pipe and the return pipeline; one end of the return pipeline is disposed in the cooling water tank; input end of the cooling water injection pump is connected with the cooling water tank by a pipe.

First claim

What is claimed is:

1. A method for continuous downhole cooling of high-temperature drilling fluid with a circulating system comprising a cooling water tank, a cooling water injection pump, a plurality of U-shaped pipes, a liquid nitrogen cooling tank, a spiral pipe, a cooling water return pump and a return pipeline, wherein the U-shaped pipes are fixed in an unsealed bond cement gap between an outer casing and an inner casing, and two ends of each of the U-shaped pipes are respectively connected with an output end of the cooling water injection pump and the spiral pipe; the spiral pipe is disposed in the liquid nitrogen cooling tank; an input end and an output end of the cooling water return pump are respectively connected with the spiral pipe and the return pipeline; one end of the return pipeline is disposed in the cooling water tank; an input end of the cooling water injection pump is connected with the cooling water tank by a pipe, the method comprising the following steps:
step A: obtaining operating parameters, environmental parameters, well structure parameters and thermal parameters of a target well;
step B: placing the plurality of U-shaped pipes downward into the unsealed bond cement gap between the outer casing and the inner casing;
step C: opening the cooling water injection pump and the cooling water return pump at the same time to make a cooling water flow from a wellhead to a downhole location, and then returning along a heat-carrying cooling water pipe of each one of the U-shaped pipes and continuously absorbing heat from the high-temperature drilling fluid in an annulus under effect of forced-convection heat transfer and heat conduction, thereby realizing the continuous downhole circulating and cooling of high-temperature drilling fluid in the annulus;
step D: calculating a circulating temperature in a drill string, a circulating temperature in the annulus, and a circulating temperature in the heat-carrying cooling water pipe by the following formulas:
formula for temperature control in the drill string:

ρ
m

⁢

A
pipe

⁢

c
m

⁢

∂

T

p
⁢
f

∂
t

=

-

ρ
m

⁢

A

p
⁢
i
⁢
p
⁢
e

⁢

v

p
⁢
i
⁢
p
⁢
e

⁢

c
m

⁢

∂

T
pf

∂
z

+

2
⁢
π
⁢

⁢

R

p
⁢
i

⁢

U

a
⁢
p

⁡

(

T
ann

-

T
pf

)

;

discrete expression of formula for temperature control in the drill string:
B 1 ( T pf ) i−1 n+1 +( A 1 −B 1 +C 1 )( T pf ) i n+1 =A 1 ( T pf ) i n +C 1 ( T ann ) i n+1 .

formula for temperature control in the annulus:

ρ
m

⁢

A
ann

⁢

c
m

⁢

∂

T

a
⁢
n
⁢
n

∂
t

=

ρ
m

⁢

A

a
⁢
n
⁢
n

⁢

v

a
⁢
n
⁢
n

⁢

c
m

⁢

∂

T
ann

∂
z

Assignees

• Univ Southwest Petroleum

Inventors

• Zhang Jie
• Li Xin
• Li Cuinan
• Zhao Zaipeng
• Chen Weilin
• He Jingbin
• Wang Peigang
• Sun Xuefeng

Classifications

• E21B36/001 Primary

  Cooling arrangements · CPC title