DRILLING-MUD COOLING SYSTEM

SYSTEME DE REFROIDISSEMENT POUR BOUE DE FORAGE

English Abstract

Drilling-fluids, called Drilling-mud, are used in drilling operations and in
some cases
become hot, generating difficulties in the operation. A system has been
invented for
cooling drilling-mud prior to returning it to the drilling operation for
reuse. The new
system consists of a cooling aggregate, a heat-exchanger and a drilling-mud
throughput system. The cooling aggregate is used to cool process cooling-fluid
circulated through a heat-exchanger. The heat-exchanger is designed with
cooling-
plates, prepared with cavities for circulation of the cooling-fluid. These
cooling
plates are stacked over each other and spaced apart in such a way that they do
not
plug and thereby avoid improper throughput when the drilling-mud, with its
high
temperature and consistency, is passed through:

The drilling-mud, coming from the drilling operation, is treated and improved
to meet
the drilling operation requirements. After treatment; the drilling-mud enters
the
system and is passed through the heat-exchanger, reducing its temperature
prior to
returning to the drilling operation.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1- A system for cooling high temperature drilling-mud, produced from drilling
operations (i.e. in the drilling of oil / gas wells) for the purpose of
returning the
drilling-mud back to the drilling operation for reuse, comprising of:

a- a cooling aggregate consisting of:
i- a refrigerator unit for cooling purposes;
ii- a cooling-tank filled with cooling-fluid which is equipped with a
cooling-element, which is connected to the said refrigerator unit (a-i)
for the purpose of cooling the said cooling-fluid;
iii- a circulating-pump connected to the said cooling-tank (a-ii) for
circulating the said cooling-fluid;
iv- a cooling-fluid pipe connected to one side of the circulating-pump (iii);
v- a back-flow pipe connected to the cooling tank (a-ii);
vi- a flow regulating valve combined with a pressure-gauge placed on the
cooling-fluid pipe ((iv) to regulate the flow of the said cooling-fluids;
b- a heat-exchanger consisting of
i- heat-exchanger body prepared with:
i-i inlet
i-ii outlet;
ii- a number of cooling-plates, prepared with circulation-cavities,
placed over each other inside the heat-exchange body (b-i) and


5



each connected to the said cooling-fluid pipe (a-iv) and the back-
flow pipe (a-v);

iii- a closing-valve, placed at the heat-exchanger outlet (b-i-ii) for
regulating the residency time of the drilling-fluid inside the said
heat-exchanger body (b-i).

c- a drilling-mud circulating system consisting of
i- a drilling-mud storage-tank filled with:
i-i drilling-mud ;
ii- a drilling-mud pump, connected on one side to the said storage-
tank (c-i-i-i) and the heat-exchanger inlet (b-i-i-i) pumping the
drilling-mud from the storage-tank (c-i) into the said heat-
exchanger inlet (b-i-i-i);
iii- a pressure-control valve along with a pressure-gauge placed
between the drilling-mud pump (c-ii) and the heat-exchanger body
(b-i) to control the pressure and the flow of the drilling-mud.
2- A system as in claim " 1" wherein the cooling-tank (a-ii), circulating-pump
(a-iii), cooling-fluid pipe (a-iv), back-flow pipe(a-v), the combined pressure-

valve and the pressure-gauge (a-vi) are eliminated and the refrigerator
cooling system is connected directly to the cooling-plates (b-ii) of the heat-
exchanger (b).

3- A system as in claim "1" wherein any suitable process cooling-fluid, i.e.
glycol, is used.


6



4- A system as in claim "1" wherein an existing, modified or newly designed
heat-exchanger is used in place of the heat-exchanger (b).

5- A system as in claim "1" wherein one or more cooling plates (1-b-ii) of the
heat-exchanger (b) are prepared with flow-dividers for even distribution of
the cooling-fluid.

6- A system as in claim "1" wherein the cooling plates (b-ii) are made of any
suitable pure- or alloy-material for improved heat exchange.

7- A system as in claim "6" wherein the cooling-plates are coated with any
coating material for any purpose, i.e. avoiding corrosion and/or adhering of
drilling mud, to the surface of the said cooling plates.

Description

CA 02377424 2002-03-28
Description
The drilling-mud returning from drilling operations must be treated and
upgraded to
meet drilling-operation requirements. In cases where the drilling-mud has high
temperatures, it must be cooled after treatment and upgrading, and prior to
returning
to the drilling operation. Cooling of the drilling-mud increases the drilling
rates and
reduces rig time; it affects rock mechanics at the bits (formation contact),
increases
well bore stability, and reduces re-work and down time. Furthermore, it
decreases the
degradation of the drilling-mud, reducing the cost of additives and upgrading
substantially. Conventional air cooling systems are not effective during the
summer
time due to their day-time temperature dependency; the cooling rate is thereby
limited
and control of the drilling-mud temperature is also limited.
The new invention
The new system consists of
A- a cooling-~g_regate: cooling the process-cooling-fluids (further referred
to as
cooling-fluid), i.e. glycol, by circulating through the cooling-plates of a
heat-
exchanger. The cooling-plates are prepared with flow-dividers inside the
plates
to direct and evenly distribute the cooling-fluid throughout the plates;
B- a drilling-mud throughput system: pumping drilling-mud from a storage tank
and passing it through the said heat-exchanger over the surface of its cooling-

2 0 plates and returning the drilling-mud for re-use to the drilling
operations;
C- a heat-exchanger:
designed and prepared with a number of cooling-plates mounted over each-
other. These plates are prepared with cavities to circulate cooling-fluids and
are
1

CA 02377424 2002-03-28
arranged with sufficient distance inside of the heat-exchanger, to avoid
plugging
and flow reduction of the drilling-mud.
Description of the drawings
Fig. 1 is a schematic of the system, according to the invention, showing:
a- refrigerator ( 1 ) connected to the cooling-element (23 ) of the cooling-
tank
(3) by the refrigerator-pipe (15) and the refrigerator-return-pipe (15a);
b- cross-sectional view of the cooling-tank (3) showing its whole cooling-
element (23);
c- cooling-fluid-pump (4) connected to the cooling-tank (3); pressure-control
valve (6) and pressure-gauge (7) connected to the cooling-fluid pipe (5)
d- cross-sectional view of the heat-exchanger (12) with its cooling-plates (8)
connected to the cooling-fluid distributor (5a) through the connectors (5b).
e- Drilling-mud storage-tank (9) filled with drilling-mud (10);
f Drilling-mud pump (24) connected to the storage-tank (9);
g- Drilling-mud pressure-valve (13) combined with the pressure-gauge (14)
mounted on the Drilling-mud pipe (10a) which is connected to the heat-
exchanger inlet (1?);
Fig. 2 is a top view schematic of the system, without the drilling-mud
throughput
system, showing also the cooling-fluid-return-pipe (22) connected to the
cooling-tank
2 0 (3) and the heat-exchanger (12).
Fig. 3 is top cross-sectional view (C-C) of one of the cooling-plates (8) with
its two
cross-sectional views (D-D and E-E) showing the flow-dividers (21) inside the
said
cooling-plate (8).
2

CA 02377424 2002-03-28
A- Cooling aggregate
The cooling aggregate consists of
a- The refrigerator (1) connected to the cooling-element (23) of the cooling-
tank
(3) which is filled with cooling-fluid (2).
b- The circulating-pump (4), connected to the cooling tank (3), pumping the
cooling-fluid (2/2a) through the cooling-fluid-pipe (5) and passing through
the
heat-exchanger cooling-plates (8) which is prepared with flow dividers (21)
to evenly direct the cooling-fluid (2b) throughout the said cooling-plate (8).
The cooling-fluid (2c) is then returned back into the cooling-tank (3) through
the cooling-fluid return-pipe (22);
c- The pressure-valve (6) combined with the pressure-gauge (7), both placed at
the cooling-pipe {5), to regulate the cooling-fluid pressure, read on the
pressure-gauge (7).
B- Drilling-mud Throughput S, s~ tem
Tl~e drilling-mud throughput system consists of
a- The storage-tank (9), filled with drilling-mud (10), connected to the
drilling-
mud pump (11) for passing the drilling-mud (10a) through the mud-pipe (16)
into ,the heat-exchanger {12), over its cooling-plates (8), and discharging
the
cooled drilling-mud (10c) through the outlet (20).
b- The pressure control-valve (13) and the pressure-gauge (14) placed on the
mud-pipe ( 16) to control the drilling-mud pressure.
D- Heat-Exchanger part
The heat-exchanger (12) is used for the exchange of the drilling-mud heat and
3

CA 02377424 2002-03-28
consists of a number of cooling-plates (8) where the cooling-fluid is re-
circulated. These cooling plates (8) are fed by the two distributors (5a)
through
connectors (5b). The drilling-mud pipe (16) is connected to the inlet (17) of
the
heat-exchanger {12). The outlet (20) ofthe heat-exchanger (12) is prepared
with
a flow-control-valve {19) to control the flow and the residency time of the
drilling-mud (10b) in the heat-exchanger (12). The cooling-plates (8) are
prepared with flow-dividers (21) to evenly distribute the cooling-fluid (2b)
throughout the inside areas of the said cooling-plates (8).
Process Descr~tion:
The cooling-fluid (2), cooled in the cooling-tank {3) through the cooling-
element (23)
connected to the refrigerator (1), is pumped by the drilling-fluid pump (4)
and passed
through the cooling-pipe (5) and the two distributors (5a) into the heat-
exchanger
cooling-plates (8) of the heat-exchanger (12) by the connectors (5b). The
pressure
valve (6) regulates the pressure reading on pressure gauge (7). After the
cooling-fluid
(2b) is circulated through the cooling-plates (8), thereby cooling the
surfaces of these
plates, the cooling-fluid (2c) is then returned, through the cooling-fluid
return-pipe
(22), to the cooling-tank (3) for re-circulation.
The drilling-mud (10) from storage tank (9) is pumped by the drilling-mud pump
{11)
into the heat-exchanger inlet {17) passing the drilling-mud (10b) over the
cooling
2 0 Plates (8) of the heat-exchanger ( 12) and thereby reducing its high
temperature,
adjusting it to the required drilling operating temperature. The cooled
drilling-mud
{10c) is then returned back to the drilling operation. The drilling-mud
circulating
pressure, read from the pressure gauge (14), is regulated by the valve (13).
4

Representative Drawing