GB2553489A

GB2553489A - Cooling system and method

Info

Publication number: GB2553489A
Application number: GB1610648.6A
Authority: GB
Inventors: Shiach Jim
Original assignee: Sces Ltd
Current assignee: Sces Ltd
Priority date: 2016-06-17
Filing date: 2016-06-17
Publication date: 2018-03-14
Anticipated expiration: 2036-06-17
Also published as: GB2553489B; GB201610648D0

Abstract

A cooling system 10 for cooling drilling fluid. The system comprises a heat exchanger 30 for facilitating heat exchange between a heat transfer medium and a drilling fluid and a cooling vessel 42 in fluid communication with the heat exchanger to permit a heat transfer medium to be cycled there between. The cooling vessel has an inlet 48 and outlet 50 for the heat transfer medium. A delivery arrangement 54 delivers a cooling medium 55into the cooling vessel to mix with and cool the heat transfer medium therein. The heat transfer medium may comprise a water/glycol mix and the cooling medium may comprise a liquefied gas such as liquid nitrogen.

Description

(71) Applicant(s):

Sees Ltd (Incorporated in the United Kingdom)

Centrifuge House, Howe Moss Terrace,

Kirkhill Industrial Estate, Dyce, Aberdeen, AB21 0GR, United Kingdom (72) Inventor(s):

Jim Shiach (56) Documents Cited:

EP 0423975 A2 WO 2004/055320 A1 US 3771718 A

WO 2016/007598 A1 US 4164127 A US 3672182 A (58) Field of Search:

INT CL E21B, F28C, F28D Other: Online: WPI, EPODOC (74) Agent and/or Address for Service:

Marks & Clerk LLP

Abercrombie Court, Prospect Road,

Arnhall Business Park, WESTHILL, Aberdeen, AB32 6FE, United Kingdom (54) Title of the Invention: Cooling system and method Abstract Title: Drilling mud cooling system (57) A cooling system 10 for cooling drilling fluid. The system comprises a heat exchanger 30 for facilitating heat exchange between a heat transfer medium and a drilling fluid and a cooling vessel 42 in fluid communication with the heat exchanger to permit a heat transfer medium to be cycled there between. The cooling vessel has an inlet 48 and outlet 50 for the heat transfer medium. A delivery arrangement 54 delivers a cooling medium 55into the cooling vessel to mix with and cool the heat transfer medium therein. The heat transfer medium may comprise a water/glycol mix and the cooling medium may comprise a liquefied gas such as liquid nitrogen.

FIGURE 1

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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COOLING SYSTEM AND METHOD

FIELD

The present invention relates to a cooling system, for example for use in cooling a product fluid, such as a drilling fluid used in the drilling of a wellbore.

BACKGROUND

Many industries require the use of fluids under controlled temperatures, and many temperature control systems are known for this purpose.

Temperature control is often required in the oil and gas exploration and production industry, for example during the drilling of wellbores which extend from surface, often for several thousands of metres, to intercept hydrocarbon bearing subterranean formations. To facilitate drilling of this scale a drill bit is mounted on the end of an elongate drill string and advanced along a required bore trajectory to form the bore. A drilling fluid is typically used (often referred to as drilling mud), pumped down the drill string and back to surface via an annulus formed between the drill string and the drilled bore, with the drilling fluid treated at surface and then recycled. The drilling fluid provides many functions, such as lubricating and cooling of the drill bit, transporting cuttings to the surface, and providing pressure control within the drilled bore to help contain fluids within the surrounding geology.

The rheology of drilling fluid may be affected by its temperature, with temperature often being of significant importance to ensure efficient functioning of the drilling fluid and thus efficiency of the drilling operation. Factors such as a high ambient wellbore temperatures and frictional heating tend to elevate the temperature of the drilling fluid. As the temperature of the drilling fluid rises, its fluid properties may change and become less suitable for its intended use. It is therefore desirable to cool the drilling fluid to maintain its use at an optimum temperature.

In offshore drilling operations seawater may be used as a cooling medium. However, in some geographical locations the ambient sea temperature may be considered too high for efficient cooling, especially while seeking to maintain sufficient drilling fluid flow rates.

Onshore drilling operations may not have a convenient source of water for use as a cooling medium. In some onshore operations air may be used as a cooling medium, although due to its low thermal conductivity this method may not be greatly efficient, particularly in regions where the ambient air temperature is relatively high, for example in tropical or desert regions.

Refrigeration systems are also known for cooling drilling fluid. However, conventional refrigeration systems, particularly industrial scale refrigeration systems, have significant energy requirements to provide the necessary work to drive the refrigeration cycle, and often have a significant footprint, which may not be practical or even possible in some drilling environments.

SUMMARY

An aspect or embodiment relates to a cooling system for cooling drilling fluid, the system comprising:

a heat exchanger for facilitating heat exchange between a heat transfer medium and a drilling fluid;

a cooling vessel in fluid communication with the heat exchanger to permit a heat transfer medium to be cycled therebetween; and a delivery arrangement for delivering a cooling medium into the cooling vessel to mix with and cool the heat transfer medium therein.

The cooling system may therefore be used to condition the temperature of (i.e., cool) a product fluid using the heat transfer medium cycling through the heat exchanger, with the temperature of the heat transfer medium itself being controlled by mixing with a cooling medium within the cooling vessel. In this respect, cooling of the heat transfer medium is achieved by use of an imported cooling medium which mixes with the heat transfer medium. This may permit appropriate temperature conditioning of the heat transfer medium to be achieved, without necessarily requiring use of refrigeration equipment or the like.

The cooling system may be used in combination with any desired product fluid. In one embodiment the cooling system may be used in combination with a drilling fluid or drilling mud, for example used during the drilling of wellbores. Accordingly, the cooling system may, in some embodiments, define a drilling fluid cooling system. In this case the heat exchanger may facilitate heat exchange between the heat transfer medium and the drilling fluid, for example prior to delivery or use of the drilling fluid in a drilling operation.

The heat transfer medium may be cycled between the heat exchanger and the cooling vessel in a flow loop. The heat exchanger and cooling vessel may define or form part of the flow loop, in that the heat exchange medium may flow, in a continuous loop, from the cooling vessel, through the heat exchanger, and returning to the cooling vessel to be appropriately mixed with and cooled by the cooling medium, with this cycle repeated.

The cooling system may comprise a volume of heat transfer medium. In some cases, the volume of heat transfer medium may be replenished or diminished, for example by a user or as a result of the cooling system performing a particular function.

The cooling system may comprise a diversion arrangement. The diversion arrangement may allow for at least a portion of the heat transfer medium to be diverted from the cooling system to an auxiliary component (which may include a system or apparatus), and optionally to be returned to the cooling system from the auxiliary component. The auxiliary component may be, for example, an engine, turbine, HVAC system or the like and may be associated with a hydrocarbon installation which may include a rig, structure, vessel or the like and may be for use in supporting exploration and production of hydrocarbons from subterranean formations, for instance. In some examples the diversion arrangement may function to divert a portion of the heat transfer medium to a single auxiliary component or multiple auxiliary components.

The diversion arrangement may be located at a point of the cooling system where the heat transfer medium flows from the cooling vessel to the heat exchanger. Thus, the diversion arrangement may divert a portion of cooled heat transfer medium. The diversion arrangement may be configured to return the diverted portion of heat transfer medium at a point in the cooling system where the heat transfer medium flows from the heat exchanger to the cooling vessel. As such, the diverted portion of heat transfer medium may bypass the heat exchanger as the heat transfer medium flows out of, and returns to, the cooling system.

The cooling system may have a primary function wherein the heat transfer medium is used to condition the temperature of a product fluid, and a secondary function wherein the heat transfer medium is flowed via the diversion arrangement to condition the temperature of an auxiliary component. In one instance, the heat transfer medium may be used preferentially for the primary function and may additionally be used for the secondary function. In some examples, the user may be able to select and/or control if or how much of the heat transfer medium is used for the secondary function.

The heat transfer medium may be selected to provide desired thermal properties, for example in accordance with the particular cooling application. The heat transfer medium may comprise a fluid. The heat transfer medium may comprise a liquid. The heat transfer medium may comprise a single fluid or a mixture of fluids. Forming the heat transfer medium from a mixture of fluids may permit desired thermal properties to be established.

The heat transfer medium may comprise a low volatility liquid, such as a liquid which is non-volatile at the expected operational pressures and temperatures.

The heat transfer medium may comprise water or water based composition. The heat transfer medium may comprise oil or oil based composition. The heat transfer medium may comprise a glycol, such as ethylene glycol, propylene glycol or the like. The heat transfer medium may comprise a water/glycol mix.

The heat transfer medium may define a relatively low freezing point, for example lower than zero degrees Celsius, such as lower than -10 degrees Celsius, lower than -20, lower than -30 degrees Celsius, lower than -40 degrees Celsius, lower than -50 degrees Celsius, or the like. Such exemplary freezing point temperatures may be those at atmospheric pressure. Such an arrangement may assist to minimise freezing of the heat transfer medium within the cooling system, for example during mixing with the cooling vessel.

The heat transfer medium may comprise a fluid which has a relatively high boiling point, for example greater than 50 degrees Celsius, such as greater than 80 degrees Celsius, greater than 90 degrees Celsius, greater than 100 degrees Celsius, or the like. Such exemplary boiling point temperatures may be those at atmospheric pressure. Such an arrangement may assist to minimise boiling/vaporisation of the heat transfer medium within the cooling system, for example within the heat exchanger.

The cooling system may comprise a source of cooling medium, wherein the delivery arrangement facilitates communication from the source of cooling medium to the cooling vessel. The source of cooling medium may comprise a volume of cooling medium.

The cooling system may comprise a storage container for storing a volume of cooling medium therein.

The storage container may comprise an insulated container, such as a vacuum insulated container or the like. Such an insulated container may permit the cooling medium to be stored at a desired temperature. This may assist to permit the cooling medium to be stored in a desired phase, such as a liquid phase. The ability to store the cooling medium at a desired temperature may permit direct use of the cooling medium from the storage container, for example without further processing or temperature conditioning.

The storage container may comprise a pressurised container. Such a pressurised container may permit the cooling medium to be stored in a desired phase, such as a liquid phase. The use of a pressurised container may permit the cooling medium to be stored under pressure, which may facilitate drive of the cooling medium from the storage container towards the cooling vessel, for example under the control of a valve system.

The source of cooling medium may comprise a cooling medium generator, for generating the cooling medium, for example in a required composition, required temperature or the like. The cooling medium generator may comprise a gas liquefier.

The cooling medium may comprise a fluid, such as a liquid or a gas. The cooling medium may be storable, and delivered to the cooling vessel, via the delivery arrangement, when required. The cooling medium may be able to be contained in a state such that no further preparation of the cooling medium is required before use. The cooling medium may be maintained such that it has a required temperature when delivered to the cooling vessel. The cooling medium may be maintained such that it is in a desired state/phase when delivered to the cooling vessel.

The cooling medium may be selected to define properties which may assist in cooling of the heat transfer medium, to provide a desired level of safety, to provide economic and/or practical benefits, or the like. The cooling medium may be selected in accordance with preferred properties, such as thermal capacitance, thermal conductivity, viscosity, boiling point or the like. For example, the cooling medium may be selected to have a boiling point below ambient temperature, such that the cooling medium can vaporise from the heat transfer medium. The cooling medium may be substantially inert, for example unreactive with the heat transfer medium.

The cooling medium may comprise a cryogenic liquid, for example a liquid with an atmospheric boiling point of below -100 degrees Celsius, such as lower than -150 degrees Celsius, for example lower than -180 degrees Celsius. Such a cryogenic fluid may provide a superior cooling effect on the heat transfer medium. For example, a cryogenic fluid may provide a faster cooling effect, which may reduce the residency time of the heat transfer fluid within the cooling vessel. Use of a cryogenic fluid may assist to minimise the volume of cooling medium required.

The cooling medium may comprise a liquefied gas (i.e., an element, composition or compound which is normally a gas at atmospheric temperature and pressure conditions). The cooling medium may comprise any one or combination of liquid nitrogen, helium, hydrogen, neon, oxygen, air or the like, or any suitable combination thereof. In one embodiment the cooling medium may comprise liquid nitrogen.

The cooling medium may be consumable. In some embodiments the cooling medium may be recycled. For example, in the case of using a liquefied gas as the cooling medium, the cooling medium may be vaporised within the cooling vessel, with the gas then collected, for example via a venting arrangement. The collected gas may be reliquefied for further use. In some embodiments the collected gas may be circulated through cooling channels, for example extending through the vessel, extending through or within a wall structure of the vessel (thus cooling the walls), or the like.

The cooling vessel may comprise a closed vessel.

The cooling vessel may be insulated, for example to assist to ensure any temperature conditioning of the heat transfer medium therein is maintained. The cooling vessel may be vacuum insulated. The cooling vessel may be lagged and/or lined with an insulating material. The cooling vessel may comprise one or more insulating wall structures. In some embodiments the cooling vessel may comprise one or more cooled wall structures. For example, one or more wall structures may comprise a flow path therein for receiving a cooling medium, such as the same cooling medium used to mix with the heat transfer medium within the vessel.

The cooling vessel may be elongate. In use the cooling vessel may be arranged horizontally. In use the cooling vessel may be arranged vertically.

The cooling vessel may comprise a vessel inlet for receiving heat transfer fluid from the heat exchanger. The cooling vessel may comprise a vessel outlet for permitting heat transfer fluid to exit the vessel and flow towards the heat exchanger. The cooling vessel may comprise a flow path therein, permitting heat transfer fluid to flow within the vessel between the vessel inlet and outlet.

The vessel inlet and outlet may be arranged at the same vertical height relative to the vessel. In such an arrangement the vessel inlet and vessel outlet may be horizontally aligned. Alternatively, the vessel inlet and outlet may be arranged at different vertical heights, such that one may be located above another. In some embodiments the vessel inlet and vessel outlet may be vertically aligned, or may be offset in a horizontal direction.

The vessel flow path may define a direct, straight or undeviated flow path between the vessel inlet and the vessel outlet.

The cooling vessel may comprise a single void or cavity. In one embodiment fluid may flow in a uniform flow path, through the void or cavity within the vessel, from inlet to outlet.

The vessel flow path may define an indirect or deviated flow path between the vessel inlet and vessel outlet. For example, the vessel flow path may be convoluted, serpentine or the like. Such an arrangement may assist to increase the residency time of the heat transfer medium with the vessel, for example to prolong exposure of the heat transfer medium to the cooling medium.

The cooling vessel may comprise a baffle arrangement for use in directing the heat transfer medium through the vessel between the vessel inlet and vessel outlet. The baffle arrangement may define the form of a flow path through the vessel from the vessel inlet to the vessel outlet.

The baffle arrangement may divide the cooling vessel into zones. The baffle arrangement may function to provide control of the flow of the heat transfer fluid between the zones. Such an arrangement may assist in providing a desired cooling effect to the heat transfer fluid during flow through the cooling vessel.

The baffle arrangement may be fixed within the cooling vessel. Such an arrangement may define a permanent or fixed flow geometry through the cooling vessel.

Alternatively, the baffle arrangement may be adjustable within the cooling vessel. Such an arrangement may facilitate adjustment of the form and geometry of the flow path through the vessel. Further, such an arrangement may provide the ability to modify the volumetric flow rate of the heat transfer medium between the vessel inlet and vessel outlet, which may provide a means of controlling the residency time of the heat transfer fluid within the vessel, and thus the cooling of the heat transfer medium.

The baffle arrangement may comprise at least one baffle member within the vessel. At least one baffle member may comprise a plate or wall structure. At least one baffle member may comprise a continuous barrier. At least one baffle member may comprise a discontinuous barrier, for example achieved by one or more holes, slots apertures or the like extending through the baffle member.

At least one baffle member may extend from a wall of the vessel. For example, at least one baffle member may be supported by a wall of the vessel.

At least one baffle member may be fixed within the vessel. For example, at least one baffle member may extend from a wall of the vessel at a fixed distance, for example a fixed height.

At least one baffle member may be variable within the vessel. For example, a baffle member may be arranged to be dynamically extended into and/or retracted from an internal space within the vessel, to vary the extent by which the baffle member extends into said internal space. The ability to vary at least one baffle member may be used to modify the flow path within the cooling vessel. The ability to vary at least one baffle member may be used to modify the volumetric flow rate of heat transfer medium through the vessel. The ability to vary at least one baffle member may be used to assist with temperature control of the heat transfer medium.

At least one baffle member may be telescopic.

The vessel inlet and vessel outlet may be separated in a first direction, and at least one baffle member may extend generally transverse to the first direction. In such an arrangement, the heat transfer medium may be diverted by the at least one transverse baffle member during flow form the vessel inlet to the vessel outlet. In some embodiments the first direction may comprise a generally horizontal direction. In such an arrangement the at least one baffle member may extend generally non-horizontally, for example, vertically, inclined, or the like. In some embodiments the first direction may comprise a generally vertical direction. In such an arrangement the at least one baffle member may extend generally non-vertically, for example, horizontally, inclined, or the like.

In one embodiment at least one baffle member may extend generally upwardly from or relative to a lower surface or region of the vessel. The at least one baffle member may extend generally vertically upwardly, or may extend upwardly in an inclined manner. The at least one baffle member may permit the heat transfer fluid to flow over an upper edge thereof. In such an arrangement the at least one baffle member may define a weir member. In some embodiments the at least one baffle member may restrict the heat transfer fluid to flow only over the upper edge thereof. For example, other edges, such as lower and side edges, of the at least one baffle member may be sealed relative to the vessel.

At least one baffle member may extend generally downwardly from or relative to an upper surface or region of the vessel. The at least one baffle member may extend generally vertically downwardly, or may extend downwardly in an inclined manner. The at least one baffle member may permit the heat transfer fluid to flow under a lower edge thereof. In such an arrangement the at least one baffle member may define a sluice member. In some embodiments the at least one baffle member may restrict the heat transfer fluid to flow only under the lower edge thereof. For example, upper and side edges of the at least one baffle member may be sealed relative to the vessel.

The baffle arrangement may comprise a plurality of baffle members. At least two (for example all) baffle members may be configured similarly. At least two (for example all) baffle members may be configured differently. At least two baffle members may be fixed relative to each other. At least two baffle members may be moveable relative to each other.

The baffle arrangement may comprise at least two baffle members arranged in a common direction or orientation. For example, at least two baffle members may define respective weir members, sluice members or the like.

The baffle arrangement may comprise at least two baffle members arranged in different directions or orientations. For example, at least one baffle member may define a weir member, and at least one baffle member may define a sluice member.

In one embodiment the baffle arrangement may comprise first and second baffle members arranged in a first direction or orientation, and a third baffle member interposed between the first and second baffle members and arranged in a second direction or orientation. Such an arrangement may establish a convoluted flow path, for example a serpentine flow path, within the cooling vessel. The second direction or orientation may be opposite the first direction or orientation. In one embodiment the first and second baffle members may define respective weir members, and the third baffle member may define a sluice member. In one embodiment the first and second baffle members may define respective sluice members, and the third baffle member may define a weir member.

The delivery arrangement may be arranged to inject cooling medium into the vessel. In such an arrangement the delivery arrangement may comprise and injection arrangement. The delivery arrangement may be arranged to inject the cooling medium into the cooling vessel under pressure.

The delivery arrangement may comprise a delivery outlet to permit cooling medium to exit the delivery arrangement into the vessel to permit mixing with the heat transfer medium. The delivery outlet may define an injection outlet. In some embodiments a single delivery outlet may be provided. Alternatively, a plurality of delivery outlets may be provided. Such an arrangement may permit cooling medium to be delivered to multiple points into or within the cooling vessel. Further, such an arrangement may facilitate optimised delivery of the cooling medium, for example in accordance with a defined flow path, for example bulk flow path, of heat transfer medium through the vessel.

The delivery outlet may function to spray cooling medium into the vessel.

In one embodiment the delivery outlet may be defined by a port in a wall of the cooling vessel.

The delivery outlet may be provided internally within the cooling vessel.

The delivery outlet may be positioned to be submerged within heat transfer fluid within the cooling vessel. Such an arrangement may facilitate immediate intimate contact between the cooling medium and the heat transfer medium.

The location of the delivery outlet may be fixed. Alternatively, the location of the delivery outlet may be variable. Such an arrangement may facilitate delivery of the cooling medium to variable locations within the cooling vessel, which may facilitate improved control or optimisation of cooling of the heat transfer medium.

The delivery arrangement may comprise at least one delivery conduit extending inside the vessel, wherein the delivery conduit comprises or defines a delivery outlet. Thus, cooling medium may be delivered internally of cooling vessel via the delivery conduit and associated delivery outlet.

The delivery outlet may be defined in a terminating end of the delivery conduit. The delivery conduit may be defined in a side wall of the delivery conduit.

In one embodiment the delivery conduit may define a single delivery outlet. Alternatively, the delivery conduit may define multiple delivery outlets.

The delivery conduit may be fixed within the vessel such that a fixed delivery outlet location is provided.

Alternatively, the delivery conduit may be adjustable within the cooling vessel such that a variable delivery outlet may be provided. Such an arrangement may facilitate control over the precise location of delivery of the cooling medium. Such an arrangement may be used to assist with temperature control of the heat transfer medium.

The delivery conduit may be telescopic.

The delivery arrangement may comprise multiple delivery conduits extending into the vessel. Such an arrangement may facilitate multiple delivery points of cooling medium within the cooling vessel.

The delivery arrangement may comprise a manifold coupled to a plurality of delivery conduits.

The delivery arrangement may comprise a valve system for assisting to control flow of cooling medium.

The delivery arrangement may comprise a conduit system for facilitating delivery of cooling medium to the cooling vessel. The conduit system may provide a communication path between a source of cooling medium and the cooling vessel. The conduit system may be coupled to or in fluid communication with one or more delivery conduits extending into the cooling vessel.

The cooling system may provide turbulent mixing between the cooling medium and the heat transfer medium. Such an arrangement may assist to improve intimate mixing and thus the efficiency of the cooling effect.

The cooling system may comprise a heat transfer medium drive arrangement for driving the heat transfer fluid between the cooling vessel and the heat exchanger. The heat transfer medium drive arrangement may comprise a pump.

The cooling system may comprise a cooling medium drive arrangement for driving the cooling medium into the cooling vessel, for example from a source. The cooling medium drive arrangement may comprise a pump.

The cooling system may be arranged such that heat transfer fluid may completely fill the cooling vessel. Alternatively, the cooling system may be arranged such that heat transfer fluid may partially fill the cooling vessel, for example to define a free surface therein. In such an arrangement a gas region may be defined above the free surface. The gas region may facilitate collection of gas, such as gas formed within the vessel, for example by vaporisation of the cooling medium.

The cooling system may comprise a venting system for facilitating venting, for example gas venting, from the cooling vessel. The venting system may be pressure operated, and arranged to permit venting when a pressure threshold has been exceeded. Such an arrangement may permit the cooling vessel to be retained at a desired pressure.

The venting system may be arranged to only vent gas, thus preventing any escape of any liquids form the cooling vessel.

The cooling system may comprise a control system. The control system may be for use in controlling the temperature of the heat transfer medium, for example to seek to supply the heat transfer medium to the heat exchanger at a desired temperature. The control system may comprise a controller and one or more temperature sensors in communication with the controller. The one or more temperature sensors may be arranged to sense temperature at one or more locations within the cooling system.

A temperature sensor may be provided to record/sense temperature at/of one or more of:

the cooling medium;

the heat transfer medium at entry to the cooling vessel; the heat transfer medium at exit from the cooling vessel; the heat transfer medium at entry to the heat exchanger; the heat transfer medium at exit from the heat exchanger; an internal region within the cooling vessel; and multiple regions within the cooling vessel.

The controller may be in communication with at least one actuator associated with the cooling system, wherein said at least one actuator is operated in accordance with the temperature sensed by one or more temperature sensors. At least one actuator may be provided to control variation of, for example, a drive pump for driving the heat transfer fluid, one or more delivery conduits within the cooling vessel, one or more baffle members of a baffle arrangement, or the like.

The heat exchanger may comprise any suitable heat exchanger, such as a shell and tube heat exchanger, plate heat exchanger, plate fin heat exchanger or the like.

An aspect or embodiment relates to a cooling method, comprising:

cycling a heat transfer medium between a cooling vessel and a heat exchanger, wherein the heat transfer medium is arranged in a heat exchange relationship with a product fluid within the heat exchanger; and delivering a cooling medium into the cooling vessel to mix with the heat transfer medium to cool the heat transfer medium therein.

The cooling method may be used to cool drilling mud.

The method may be performed using a cooling system according to any other aspect.

An aspect or embodiment relates to cooling vessel for use in a cooling system, such as a cooling system defined in any other aspect.

An aspect or embodiment relates to a temperature control system, comprising:

a heat exchanger for facilitating heat exchange between a heat transfer medium and a product fluid;

a temperature control vessel in fluid communication with the heat exchanger to permit a heat transfer medium to be cycled therebetween in a flow loop; and a temperature control medium delivery system for delivering a temperature medium into the temperature control vessel to mix with the heat transfer medium therein.

An aspect or embodiment relates to a drilling fluid cooling system, comprising:

An aspect or embodiment relates to a cooling system, comprising:

a cooling vessel in fluid communication with the heat exchanger to permit a heat transfer medium to be cycled therebetween;

a delivery arrangement for delivering cooling medium into the cooling vessel to mix with and cool the heat transfer medium therein; and a diversion arrangement for diverting at least a portion of the heat transfer medium between the cooling system and an auxiliary component.

An aspect or embodiment relates to a cooling system, comprising:

a cooling vessel defining an outlet for delivering a heat transfer medium from the cooling vessel to a cooled apparatus, and an inlet for receiving the heat transfer medium from the cooled apparatus into the cooling vessel; and a delivery arrangement for delivering a cooling medium in to the cooling vessel to mix with and cool the heat transfer medium therein.

The cooled apparatus may comprise a heat exchanger.

The cooled apparatus may comprise apparatus associated with a hydrocarbon installation, such as an onshore installation, offshore installation or the like. The hydrocarbon installation may include a rig, structure, vessel or the like. For example, for use in supporting exploration and production of hydrocarbons form subterranean formations.

It should be understood that features defined in relation to one aspect or embodiment may be applied or used in any other aspect or embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects or embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic illustration of an embodiment of a cooling system for use in cooling a drilling fluid associated with the drilling of a subterranean wellbore.

Figure 2 is a diagrammatic illustration of an embodiment of a cooling vessel forming part of a cooling system.

Figure 3 is a diagrammatic illustration of the cooling vessel of Figure 2, shown in a modified configuration.

Figure 4 is a diagrammatic illustration of a cooling vessel forming part of a cooling system according to an alternative embodiment.

Figure 5 is a diagrammatic illustration of a cooling vessel forming part of a cooling system according to a further alternative embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

Aspects and embodiments of the present invention relate to a cooling system which may be used to provide cooling of any desired product fluid. However, for exemplary purposes, the following description illustrates embodiments of a cooling system for use in cooling a drilling fluid or mud associated with the drilling of a subterranean formation, for example drilled to intercept a subterranean hydrocarbon bearing formation.

Thus, Figure 1 illustrates an exemplary embodiment of a cooling system, generally identified by reference numeral 10, which is used for cooling a drilling mud associated with an operation for drilling a wellbore 12. The wellbore 12 is drilled using a drill bit 14 on the end of a drill string 16, with the drill string 16 either rotated from surface or via a downhole motor. Drilling mud is delivered downhole, via pump 17, through the drill string 16, as illustrated by arrows 18, exits through the drill bit 14 and returns to surface via an annulus 20 formed between the drill string 16 and the formed wellbore 12, as illustrated by arrows 22.

The drilling mud has numerous functions, such as lubricating and cooling of the drill bit 14, transporting cuttings to the surface via the annulus 20, and providing pressure control within the wellbore 12 to help contain fluids within the surrounding geology 24 and minimise the risk of a blow-out.

Drilling mud is typically specially manufactured to provide desired properties, such as density, viscosity and the like, and can be responsible for a significant proportion of the costs in drilling a wellbore. Accordingly, there is a desire in the art to recycle the drilling mud, which typically involves treating the mud returning from the wellbore 12 via surface treatment equipment, generally identified by reference numeral 26. Such surface treatment equipment 26 may include separators, shale shakers and the like.

The rheology of drilling fluid may be affected by its temperature, with temperature often being of significant importance to ensure efficient functioning of the drilling mud and thus efficiency of the drilling operation. Factors such as a high ambient wellbore temperatures and frictional heating tend to elevate the temperature of the drilling mud. As the temperature of the drilling mud rises, its fluid properties may change and become less suitable for its intended use. It is therefore desirable to cool the drilling mud to maintain its use at an optimum temperature. The cooling system 10 of the present embodiment can provide such cooling.

The cooling system 10 comprises a heat exchanger 30 which defines a mud inlet 32 for receiving drilling mud from the treatment equipment 26, and a mud outlet 34 for delivering appropriately temperature conditioned mud to be returned to the wellbore 12 via pump 17. The heat exchanger 30 may be any suitable heat exchanger, such as a shell and tube heat exchanger.

The heat exchanger 30 also defines a heat transfer medium inlet 36 and a heat transfer medium outlet 38, which permit a heat transfer medium, such as a water/glycol mix, to flow through the heat exchanger 30, driven by pump 40, in heat exchange relationship with the drilling mud.

The cooling system 10 also includes a cooling vessel 42 in fluid communication with the heat exchanger 30 to permit the heat transfer medium (illustrated by reference numeral 43) to be cycled between the heat exchanger 30 and cooling vessel 42, through feed and return piping 44, 46 and driven by pump 40. The cooling vessel 42 includes a vessel inlet 48 for receiving the heat transfer medium 43 from the heat exchanger 30, and a vessel outlet 50 for delivering the heat transfer medium 43 from the cooling vessel 42 to the heat exchanger 30. The cooling vessel 42 also defines an internal flow path 52 allowing the heat transfer medium 43 to flow within the vessel 42 between its inlet 48 and outlet 50.

Diversion arrangement 45 may be optionally attached to feed piping 44. The diversion arrangement 45 permits the diversion of heat transfer medium 43 from the feed piping 44 to auxiliary components (not shown in Figure 1). A user can control the flow of heat transfer medium 43 to auxiliary components by the opening or closure of valves 47, 49a-d as desired. The diversion arrangement 45 may permit the heat transfer medium 43 to be used as a coolant for the cooling of engines or turbines, in HVAC systems, for on-site refrigeration or the like.

Although not shown in the Figures, the diversion arrangement 45 may permit diverted heat transfer medium 43 to flow back into the cooling system, for example flow back into the cooling vessel 42.

The cooling system 10 also includes a delivery arrangement 54 which communicates a cooling medium 55, in this example a cryogenic fluid such as liquid nitrogen, from a storage vessel 56 and into the cooling vessel 42 to mix with and cool the heat transfer medium 43 flowing therethrough.

The cooling system 10 may therefore be used to condition the temperature of (i.e., cool) the drilling mud using the heat transfer medium 43 cycling through the heat exchanger 30, with the temperature of the heat transfer medium 43 itself being controlled by mixing with the cooling medium 55 within the cooling vessel 42. In this respect, cooling of the heat transfer medium 43 is achieved by use of an imported cooling medium 55 which mixes with the heat transfer medium 43. This may permit appropriate temperature conditioning of the heat transfer medium 43 to be achieved, without necessarily requiring use of refrigeration equipment or the like, which may otherwise require significant on-site energy requirements which might be difficult to provide in typical drilling environments. Furthermore, the present embodiment may eliminate the requirement to rely on any ambient resource, such as air or seawater (e.g., in offshore drilling operations). In this respect, in some geographical locations the ambient air and sea temperatures may be considered too high for efficient cooling, especially while seeking to maintain sufficient drilling fluid flow rates. Further, significant volumes of natural resources, such as water might not be readily available.

Figure 2 provides a diagrammatic illustration of the cooling system 10 of Figure 1, with internal details of the cooling vessel 42 shown. The cooling vessel 42 includes a baffle arrangement 60 which in the embodiment shown includes first, second and third baffle members 62, 64, 66 arranged in a generally vertical orientation. The first and third baffle members 62, 66 extend upwardly from a lower wall or base 68 of the cooling vessel 42 and form respective upper passages 70, 72 with an upper wall 74 of the vessel 42. The first and third baffle members 62, 66 are sealed relative to the internal surface of the vessel 42 such that flow of heat transfer medium 43 from the vessel inlet 48 towards the vessel outlet 50 is only possible past the first and third baffle members 62, 66 through the upper passages 70, 72. As such, the first and third baffle members 62, 66 may be defined as weir members.

The second baffle member 64 is positioned intermediate the first and third baffle members 62, 66 and extends downwardly from the upper wall 74 of the vessel 42 to form a lower passage 76 with the base 68 of the vessel 42. The second baffle member 64 is sealed relative to the internal surface of the vessel 42 such that flow of heat transfer medium 43 from the vessel inlet 48 towards the vessel outlet 50 is only possible past the second baffle members 64 through the lower passage 76. As such, the second baffle member 62, 66 may be defined as a sluice member.

In the configuration illustrated in Figure 2, the baffle members 62, 64, 66 create a serpentine flow path 78 (shown in broken outline) extending through the vessel 42 between its inlet 48 and outlet 50. Such an arrangement may assist to provide a degree of control over the volumetric flow rate of the heat transfer medium 43 through the vessel 42, which may provide advantages in terms of controlling the residence time of the heat transfer medium 43 to facilitate cooling by the cooling medium 55 delivered via the delivery arrangement 54.

In the present embodiment the delivery arrangement 54 includes a supply pipe 80 which is connected between the storage vessel 56 and a manifold 82. A plurality of delivery conduits 84 extend from the manifold 82 and into the vessel 42, with the terminating end of each delivery conduit 84 defining an outlet 86 for permitting cooling medium 55 to be injected into the vessel 42 and into immediate intimate contact with the heat transfer medium 43. In the embodiment shown the outlets 86 of the delivery conduits 84 are arranged at a height to be in general alignment with the bulk flow path 78 (which in this case may be a serpentine flow path). The bulk flow path 78 extends through the vessel 42 and represents the flow path from the inlet 48 to outlet 50 experiencing the highest average volume flow rate of heat transfer medium 43. The bulk flow path 78 may be the path of least resistance to flow. By placing the outlets 86 of the delivery conduits 84 in general alignment with the bulk flow path 78, it is sought to maximise the exposure of the flowing heat transfer medium 43 to the injected cooling medium 55, and thus maximise the cooling effect.

Although not illustrated, one or more of the delivery conduits 84 may include a heating arrangement, for example in the vicinity of the outlets 86, to address any issues of frozen material blocking the delivery of the cooling medium.

In the embodiment illustrated, each delivery conduit 84 includes a control valve 85 to provide independent control of cooling medium 55 via the individual delivery conduits 84.

In the embodiment shown the heat transfer medium 43 does not completely fill the internal volume of the vessel 42, and defines a free surface 88, with a gas space 90 defined between the free surface 88 and the upper wall 74 of the vessel 42. This gas space 90 may provide a region for vaporised cooling medium 55, which has bubbled through the heat transfer medium 43, to collect within the vessel 42.

A gas vent 92 is provided in communication with the gas space 90, to permit gas to vent from the vessel 42, for example in accordance with a vessel pressure threshold. In some embodiments the vented gas may be disposed of in accordance with necessary legislation. In some embodiments some or all of the vented gas may be recycled, as illustrated by broken line 94, for re-use, for example via a gas liquefier (not shown). In some embodiments some or all of the vented gas may be delivered, as illustrated by broken line 96, to a cooling jacket 98 which surrounds some or all of the vessel 42. In this respect, where the vented gas is still of a low temperature this arrangement may provide an additional cooling effect. Spent gas from the cooling jacket 98 may be disposed of or recycled, for example back to the storage vessel 56.

In the example embodiment illustrated in Figure 2 the cooling system 10 further includes a control system 100 which includes a controller 102 and a number of temperature sensors 104 in communication with the controller 102. The sensors 104 are arranged to measure temperature at a number of locations within the cooling system 10, such as within various zones of the cooling vessel 42 (for example zones defined by the baffle arrangement 60), inlet and exit points of the heat exchanger 30, inlet and exit points of the cooling vessel 42 and the like. Such temperature measurements may be fed to the controller 102, wherein the controller may, in accordance with loaded protocols or algorithms, provide control to components of the cooling system, such as pump 40, valves 85 etc., to seek to establish cooling of the drilling mud within desired parameters.

Control system 100 may additionally or alternatively be used to control the flow of heat transfer medium 43 through diversion arrangement 45 via actuation of valve 47. In one example, the control system 100 may be configured to restrict or increase the flow of heat transfer medium 43 through valve 47 depending on the load requirements of the heat exchanger 30. For example, when the heat exchanger 30 is required to operate under an increased load, then valve 47 may be configured to restrict the flow of heat transfer medium 43 through diversion arrangement 45 such that the flow rate of heat transfer medium 43 through the heat exchanger 30 may be increased.

The control system 100 may be in communication with an auxiliary component or components (not shown) that receive heat transfer medium 43 through the diversion arrangement 45. The control system 100 may be able to control the flow of heat transfer medium 43 to an auxiliary component to ensure that the auxiliary component receives a sufficient supply of heat transfer medium 43. In the case where the control system may restrict the flow of heat transfer medium 43 to an auxiliary component so that the heat transfer medium 43 can be used in the heat exchanger 30, the control system may be able to ensure that the auxiliary component is not damaged as a result of a reduced flow rate of heat transfer medium 43. For example, the control system 100 may be able to restrict functionality of an auxiliary component to ensure that it does not overheat.

In the embodiment of Figure 2 the baffle members 62, 64, 66 and the delivery conduits 84 are illustrated at a certain height within the vessel 42. In some embodiments this height may be fixed. However, in other embodiments this height may be variable, which may provide advantages in allowing further control over the cooling effect within the vessel 42. Figure 3 provides a further diagrammatic illustration of the cooling vessel 42 of Figure 2, with baffle members 62, 64, 66 and delivery conduits 84 shown in alternative positions/heights within the vessel 42. There may be many matters taken into account when considering which specific arrangement is selected. For example, if it is determined that a target temperature of the heat transfer medium 43 is achieved perhaps around the point of the heat transfer medium 43 flowing over the first baffle member 62, as illustrated by arrow 110, it may not be necessary to maintain a serpentine flow path, and, as illustrated, the second baffle member 64 may be raised and the third baffle member 66 may be lowered. Further, in some cases it may be desirable to adjust the heights of the outlets 86 of the delivery conduits, for example to accommodate the revised flow path through the vessel 42. Also, in some cases it may be desirable to close or restrict one or more of the valves 85 to permit limit or prevent injection of the cooling medium 55 at certain points.

In some embodiments control of the baffle arrangement 60 and the delivery conduits 84 may be achieved via the control system 100.

In the embodiment illustrated in Figure 3 the baffle members 62, 64, 66 of the baffle arrangement 60 are arranged in varying directions to provide a combination of weirs and sluices. However, in other embodiments the baffle members may be arranged in a common direction. One example is illustrated in Figure 4, in which all baffle members 62, 64, 66 extend upwardly from the base 68 of the vessel.

In the embodiments illustrated above the cooling vessel is generally elongate and horizontally aligned. However, in other embodiments the vessel may be vertically aligned, as illustrated in Figure 5, in which a cooling system, generally identified by reference numeral 110 is illustrated. The cooling system 110 of Figure 5 is generally similar to the system 10 of Figure 2 and as such like features share like reference numerals, incremented by 100. Accordingly, the cooling system 110 includes a heat exchanger 130 which defines a mud inlet 132 for receiving drilling mud, and a mud outlet 134 for delivering appropriately temperature conditioned mud to be returned to a wellbore (e.g., wellbore 12 of Figure 1).

The heat exchanger 130 also defines a heat transfer medium inlet 136 and a heat transfer medium outlet 138, which permit a heat transfer medium to flow through the heat exchanger 130 in heat exchange relationship with the drilling mud.

The cooling system 110 also includes a cooling vessel 142 in fluid communication with the heat exchanger 130 to permit the heat transfer medium (illustrated by reference numeral 143) to be cycled between the heat exchanger 130 and cooling vessel 142. The cooling vessel 142 includes a vessel inlet 148 for receiving the heat transfer medium 143 from the heat exchanger 130, and a vessel outlet 150 for delivering the heat transfer medium 143 from the cooling vessel 142 to the heat exchanger 130.

The cooling system 110 also includes a delivery arrangement 154 which communicates a cooling medium 155, in this example a cryogenic fluid such as liquid nitrogen, from a storage vessel 156 and into the cooling vessel 142 to mix with and cool the heat transfer medium 143 flowing therethrough.

In the present embodiment the cooling vessel 142 is generally vertically arranged, 5 which may provide advantages in some uses, for example by minimising the footprint of the vessel 142 without necessary reducing its capacity.

The delivery arrangement 154 includes a single delivery conduit 184 which extends into the vessel 142 and defines a number of delivery outlets 186 along its length to facilitate injection of cooling medium 155 at multiple points within the vessel 142.

In some embodiments, the vessel 142 may include internal control surfaces to impart rotation to the heat transfer medium 142, with such rotation illustrated by arrows 2. The rotational flow within the vessel 142 may assist to encourage mixing between the cooling medium 155 and the heat transfer medium 143, and thus improve cooling efficiency.

It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the present invention. For example, any number of baffle members may be provided, and such baffle members may be provided in any orientation. Also, any number of delivery conduits may be provided.

Claims

CLAIMS:

1. A cooling system for cooling drilling fluid, the system comprising:

2. The cooling system according to claim 1, comprising a source of cooling medium.

3. The cooling system according to claim 1 or 2, comprising a storage container for storing a volume of cooling medium therein.

4. The cooling system according to any preceding claim, comprising a cooling medium generator for generating the cooling medium.

5. The cooling system according to any preceding claim, wherein the cooling medium comprises a fluid.

6. The cooling system according to any preceding claim, wherein the cooling medium comprises a liquefied gas.

7. The cooling system according to any preceding claim, wherein the cooling medium is consumable.

8. The cooling system according to any preceding claim, wherein the cooling vessel comprises an inlet and an outlet, and the cooling vessel defines a deviated flow path between the vessel inlet and vessel outlet.

9. The cooling system according to claim 8, wherein the cooling vessel comprises a baffle arrangement to direct the heat transfer medium through the vessel between the vessel inlet and the vessel outlet.

10. The cooling system according to claim 9, wherein the baffle arrangement divides the cooling vessel into zones, and the baffle arrangement functions to provide control of the flow of the heat transfer fluid between the zones to assist in providing a desire cooling effect to the heat transfer fluid during flow through the cooling vessel.

11. The cooling system according to claim 9 or 10, wherein the baffle arrangement is adjustable within the cooling vessel.

12. The cooling system according to any preceding claim, wherein the delivery arrangement is arranged to inject cooling medium into the vessel.

13. The cooling system according to any preceding claim, wherein the delivery arrangement comprises a delivery outlet positioned to be submerged within heat transfer medium within the cooling vessel.

14. The cooling system according to claim 13, wherein the location of the delivery outlet is variable.

15. The cooling system according to any preceding claim, wherein the delivery arrangement comprises at least one delivery conduit extending inside the cooling vessel, wherein the at least one delivery conduit is adjustable within the cooling vessel so as to provide a variable delivery outlet.

16. The cooling system according to any preceding claim, wherein turbulent mixing is provided between the cooling medium and the heat transfer medium.

17. The cooling system according to any preceding claim, comprising a control system.

18. The cooling system according to any preceding claim, comprising a diversion arrangement.

19. The cooling system according to claim 18, wherein the diversion arrangement allows for a portion of the heat transfer medium to be diverted from the cooling system to an auxiliary component.

20. The cooling system according to claim 18 or 19, wherein the diversion arrangement is located at a point of the cooling system where the heat transfer medium flows for the cooling vessel to the heat exchanger.

21. The cooling system according to any preceding claim, having a primary function wherein the heat transfer medium is used to condition the temperature of a product fluid, and a secondary function wherein the heat transfer medium is flowed via the diversion arrangement to condition the temperature of an auxiliary component.

22. A cooling method for use in cooling drilling fluid, comprising:

cycling a heat transfer medium between a cooling vessel and a heat exchanger, wherein the heat transfer medium is arranged in a heat exchange relationship with a drilling fluid within the heat exchanger; and delivering a cooling medium into the cooling vessel to mix with the heat transfer medium to cool the heat transfer medium therein.

23. The cooling method according to claim 22, comprising diverting at least a portion of the heat transfer medium to an auxiliary component.

24. A cooling system, comprising:

a cooling vessel defining an outlet for delivering a heat transfer medium from the cooling vessel to a cooled apparatus, and an inlet for receiving the heat transfer

30 medium from the cooled apparatus into the cooling vessel; and a delivery arrangement comprising a plurality of delivery outlets for delivering a cooling medium in to the cooling vessel to mix with and cool the heat transfer medium therein, at least two of the plurality of delivery outlets having different vertical positions within the cooling vessel.

Intellectual

Property

Office

Application No: Claims searched:

24. A temperature control system, comprising:

25. A cooling system, comprising:

a cooling vessel defining an outlet for delivering a heat transfer medium from the cooling vessel to a cooled apparatus, and an inlet for receiving the heat transfer medium from the cooled apparatus into the cooling vessel; and a delivery arrangement for delivering a cooling medium in to the cooling vessel 5 to mix with and cool the heat transfer medium therein.

Amendments to the Claims have been filed as follows:

1201 18

CLAIMS:

1. A cooling system for cooling drilling fluid, the system comprising:

a heat exchanger for facilitating heat exchange between a heat transfer medium 5 and a drilling fluid;

a cooling vessel in fluid communication with the heat exchanger to permit a heat transfer medium to be cycled therebetween; and a delivery arrangement comprising a plurality of delivery outlets for delivering a cooling medium into the cooling vessel to mix with and cool the heat transfer medium therein,

10 at least two of the plurality of delivery outlets having different vertical positions within the cooling vessel.

15 3. The cooling system according to claim 1 or 2, comprising a storage container for storing a volume of cooling medium therein.

6. The cooling system according to any preceding claim, wherein the cooling

25 medium comprises a liquefied gas.

30 8. The cooling system according to any preceding claim, wherein the cooling vessel comprises an inlet and an outlet, and the cooling vessel defines a deviated flow path between the vessel inlet and vessel outlet.

5 10. The cooling system according to claim 9, wherein the baffle arrangement divides the cooling vessel into zones, and the baffle arrangement functions to provide control of the flow of the heat transfer fluid between the zones to assist in providing a desire cooling effect to the heat transfer fluid during flow through the cooling vessel.

10 11. The cooling system according to claim 9 or 10, wherein the baffle arrangement is adjustable within the cooling vessel.

o

CM

13. The cooling system according to any preceding claim, wherein at least one of the plurality of delivery outlets is positioned to be submerged within heat transfer medium within the cooling vessel.

20 14. The cooling system according to claim 13, wherein the location of at least one of the plurality of delivery outlets is variable.

15. The cooling system according to any preceding claim, wherein the delivery arrangement comprises at least one delivery conduit extending inside the cooling

25 vessel, wherein the at least one delivery conduit is adjustable within the cooling vessel so as to provide a variable delivery outlet.

18. The cooling system according to any preceding claim, comprising a diversion 35 arrangement.

10 21. The cooling system according to any preceding claim, having a primary function wherein the heat transfer medium is used to condition the temperature of a product fluid, and a secondary function wherein the heat transfer medium is flowed via the diversion arrangement to condition the temperature of an auxiliary component.

o

CM

15 22. A cooling method for use in cooling drilling fluid, comprising:

cycling a heat transfer medium between a cooling vessel and a heat exchanger, wherein the heat transfer medium is arranged in a heat exchange relationship with a drilling fluid within the heat exchanger; and delivering a cooling medium via a delivery arrangement comprising a plurality of 20 delivery outlets into the cooling vessel to mix with the heat transfer medium to cool the heat transfer medium therein, at least two of the plurality of delivery outlets having different vertical positions within the cooling vessel.

23. The cooling method according to claim 22, comprising diverting at least a 25 portion of the heat transfer medium to an auxiliary component.