INSTRUMENTATION

FIELD OF THE INVENTION

The present disclosure generally relates to in situ hydrocarbon recovery operations, and more particularly, to a method and apparatus for downhole deployment of well instrumentation for in situ hydrocarbon recovery.

BACKGROUND TO THE INVENTION

Hydrocarbons obtained from subterranean formations are often used as energy resources, as feedstocks, and as consumer products. Concerns over depletion of available hydrocarbon resources and concerns over declining overall quality of produced hydrocarbons have led to development of processes for more efficient recovery, processing and/or use of available hydrocarbon resources. In situ processes may be used to extract hydrocarbon materials from subterranean formations that were previously inaccessible and/or too expensive to extract using available methods.

Chemical and/or physical properties of hydrocarbon material in a subterranean formation may need to be changed to allow hydrocarbon material to be more easily removed from the subterranean formation and/or increase the value of the hydrocarbon material. The chemical and physical changes may include in situ reactions that produce removable fluids, composition changes, solubility changes, density changes, phase changes, and/or viscosity changes of the hydrocarbon material in the formation.

Heaters may be placed in wellbores to heat a formation during an in situ process. Examples of in situ processes utilizing downhole heaters are illustrated in U.S. Patent Nos. 2,634,961 to Ljungstrom; 2,732,195 to Ljungstrom; 2,780,450 to Ljungstrom; 2,789,805 to Ljungstrom; 2,923,535 to Ljungstrom; 4,886,118 to Van Meurs et al.; and 6,688,387 to Wellington et al., each of which is incorporated by reference as if fully set forth herein. There are many different types of heaters which may be used to heat the formation; a typical type of such heaters can be formed by inserting mineral insulated (MI) cables into coiled tubing.

Currently, various challenges still exist in the area of techniques for downhole deployment of well instrumentation in in situ hydrocarbon recovery operations. For instance, it is a very time consuming and complicated process to deploy heaters in presence of a production pump. US patent application publication No. 20150354302A1 discusses a transition device for deploying instrumentation below a downhole tool, wherein it is proposed to take an instrument line and cross over a portion to the outside an a reverse direction for communication with the reservoir past the pump which could stay in place when the pump is removed. However, the disclosed device is not making the deployment faster, and if the heater is made by inserting MI cables inside coiled tubing, the device cannot prevent formation fluid from entering the coiled tubing, which might lead to serious consequences in high temperature conditions.

SUMMARY OF THE INVENTION

Therefore, it might be advantageous to provide an assembly and method which can achieve one or more of the followings: 1) restricting movement of MI cables due to thermal expansion and/or contraction; 2) providing necessary crossover from the coiled tubing to the production tubing and allowing the coiled tubing to be attached to the production tubing below the intake of the pump; 3) enabling the MI cables and instrument strings get out of the coiled tubing to run around the pump and get strapped onto the exterior of the production tubing for the remaining distance from the downhole location to the wellhead at the ground surface; 4) preventing formation fluids from entering the coiled tubing; 5) allowing for a faster deployment and reducing the risk of getting hung up (because there is a smooth surface in the lateral that does not have cables and clamps strapped to it trying to be deployed).

According to an aspect of the present invention, there is provided an assembly for downhole deployment of well instrumentation, the assembly being above a coiled tubing which receives a part of a cable assembly and below a production tubing, the assembly comprising: a splitted hanger fixing the cable assembly outside the coiled tubing; a seal connectable to the splitted hanger, configured to prevent formation fluid from entering the coiled tubing; a set of connectors, configured to connect the assembly to the coiled tubing.

Optionally, the set of connectors comprising: a coiled tubing connector, configured to connect the assembly to the coiled tubing; a lower connector, an upper part of the lower connector being adapted to receive, at least in part, the splitted hanger and the seal. Optionally, the set of connectors further comprising: an upper connector arranged above the lower connector, and an adjusting nut; the upper connector and the adjusting nut being connectable to each other, thereby fixing the assembly relative to the coiled tubing; a lower part of the upper connector having an exit enabling the cable assembly to extend out of the assembly.

Optionally, the adjusting nut has a flange extruding radially inward and the lower connector has a flange extruding radially outward.

Optionally, the assembly further comprising an end cap, which is connectable to the splitted hanger via the seal.

According to another aspect of the present invention, there is provided a method for downhole deployment of well instrumentation, comprising: providing an assembly being above a coiled tubing which receives a part of a cable assembly and below a production tubing, the assembly comprising: a splitted hanger fixing the cable assembly outside the coiled tubing; a seal connectable to the splitted hanger, configured to prevent formation fluid from entering the coiled tubing; a set of connectors, configured to connect the assembly to the coiled tubing.

Optionally, the set of connectors comprising: a coiled tubing connector, configured to connect the assembly to the coiled tubing; a lower connector, an upper part of the lower connector being adapted to receive, at least in part, the splitted hanger and the seal.

Optionally, the set of connectors further comprising: an upper connector arranged above the lower connector, and an adjusting nut; the upper connector and the adjusting nut being connectable to each other, thereby fixing the assembly relative to the coiled tubing; a lower part of the upper connector having an exit enabling the cable assembly to extend out of the assembly.

Optionally, the adjusting nut has a flange extruding radially inward and the lower connector has a flange extruding radially outward.

Optionally, the assembly further comprising an end cap, which is connectable to the splitted hanger via the seal.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements.

Fig. 1 is an illustration of a wellbore instrumentation deployed using the assembly and method according to an embodiment of the present invention;

Fig. 2 is an enlarged view of section 58 of the wellbore instrumentation in Fig. l;

Fig. 3 is an explosive view showing the assembly for downhole deployment of well instrumentation according to an embodiment of the present invention;

Figs. 4-11 illustrate a process of installing the assembly according to certain embodiments of the present invention;

Figs. 12a- 12g illustrate section views of the wellbore instrumentation in Figs.

1-2.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

Below is a table listing the reference numerals for the elements.

35a a first part of the end cap

35b a second part of the end cap

352 recess on the end cap (for receiving the MI cables)

36 coiled tubing connector

37 alien screws (for serially coupling the end cap, the seal and the hanger)

4 ground surface

40 end termination (of the coiled tubing)

51 casing

52 production tubing

532 injection nozzle for heated fluid such as water, steam

54 coiled tubing

55 tube

552 duplex fibre optic

56 a portion of the system where the proposed assembly is located

58 a portion of the system an enlarged view of which is shown in

Fig. 2

61 pipe connector

62 MI splice

DETAILED DESCRIPTION OF THE INVENTION

Certain terms used herein are defined as follows:

An "artificial lift" refers to the use of artificial means to increase the flow of liquids, such as crude oil or water, from a production well. Generally this is achieved by the use of a mechanical device inside the well (known as pump or velocity string) or by decreasing the weight of the hydrostatic column by injecting gas into the liquid some distance down the well. Artificial lift is needed in wells when there is insufficient pressure in the reservoir to lift the produced fluids to the surface, but often used in naturally flowing wells (which do not technically need it) to increase the flow rate above what would flow naturally. The produced fluid can be oil, water or a mix of oil and water, typically mixed with some amount of gas.

In the context of reduced heat output heating systems, apparatus, and methods, the term "automatically" means such systems, apparatus, and methods function in a certain way without the use of external control (for example, external controllers such as a controller with a temperature sensor and a feedback loop, PID controller, or predictive controller).

"Coupled"/ "connected" means either a direct connection or an indirect connection (for example, one or more intervening connections) between one or more objects or components. The phrase "directly connected" means a direct connection between objects or components such that the objects or components are connected directly to each other so that the objects or components operate in a "point of use" manner.

A "formation" includes one or more hydrocarbon containing layers, one or more non-hydrocarbon layers, an overburden, and/or an underburden. "Hydrocarbon layers" refer to layers in the formation that contain hydrocarbons. The hydrocarbon layers may contain non-hydrocarbon material and hydrocarbon material. The "overburden" and/or the "underburden" include one or more different types of impermeable materials. For example, the overburden and/or underburden may include rock, shale, mudstone, or wet/tight carbonate. In some embodiments of in situ heat treatment processes, the overburden and/or the underburden may include a hydrocarbon containing layer or hydrocarbon containing layers that are relatively impermeable and are not subjected to temperatures during in situ heat treatment processing that result in significant characteristic changes of the hydrocarbon containing layers of the overburden and/or the underburden. For example, the underburden may contain shale or mudstone, but the underburden is not allowed to heat to pyrolysis temperatures during the in situ heat treatment process. In some cases, the overburden and/or the underburden may be somewhat permeable.

"Formation fluids" refer to fluids present in a formation and may include pyrolyzation fluid, synthesis gas, mobilized hydrocarbons, and water (steam).

Formation fluids may include hydrocarbon fluids as well as non-hydrocarbon fluids. The term "mobilized fluid" refers to fluids in a hydrocarbon containing formation that are able to flow as a result of thermal treatment of the formation. "Produced fluids" refer to fluids removed from the formation.

A "heater"/ "heat source" is a system for providing heat to at least a portion of a formation substantially by conductive heat transfer. For example, a heater may include electrically conducting materials and/or electric heaters such as an insulated conductor, an elongated member, and/or a conductor disposed in a conduit.

"Hydrocarbons" are generally defined as molecules formed primarily by carbon and hydrogen atoms. Hydrocarbons may also include other elements such as, but not limited to, halogens, metallic elements, nitrogen, oxygen, and/or sulfur. Hydrocarbons may be, but are not limited to, kerogen, bitumen, pyrobitumen, oils, natural mineral waxes, and asphaltites. Hydrocarbons may be located in or adjacent to mineral matrices in the earth. Matrices may include, but are not limited to, sedimentary rock, sands, silicilytes, carbonates, diatomite, and other porous media. "Hydrocarbon fluids" are fluids that include hydrocarbons. Hydrocarbon fluids may include, entrain, or be entrained in non-hydrocarbon fluids such as hydrogen, nitrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, water, and ammonia.

An "in situ conversion process" refers to a process of heating a hydrocarbon containing formation from heat sources to raise the temperature of at least a portion of the formation above a pyrolysis temperature so that pyrolyzation fluid is produced in the formation.

An "in situ heat treatment process" refers to a process of heating a hydrocarbon containing formation with heat sources to raise the temperature of at least a portion of the formation above a temperature that results in mobilized fluid, visbreaking, and/or pyrolysis of hydrocarbon containing material so that mobilized fluids, visbroken fluids, and/or pyrolyzation fluids are produced in the formation.

"Instrument strings" refer to any elongated cables, lines deployed in downhole in addition to MI cables, with or without attachment (e.g. sensors). Instrument strings might include but are not limited to any of the following: fibre optic cable, sensor cable, thermocouple cable.

"Insulated conductor" refers to any elongated material that is able to conduct electricity and that is covered, in whole or in part, by an electrically insulating material.

The term "wellbore" refers to a hole in a formation made by drilling or insertion of a conduit into the formation. A wellbore may have a substantially circular cross section, or another cross-sectional shape. As used herein, the terms "well" and "opening," when referring to an opening in the formation may be used interchangeably with the term "wellbore." A wellbore may be substantially vertical, like "I", or include a substantially vertical part and a substantially horizontal part, like "L".

Throughout the present specification, unless specified differently, the terms "above", "upper", "upward", "upstream" and similar terms refer to a direction closer to the head of a wellbore or the ground surface, while the teams "ahead", "below",

"forward", "downward", "lower", "downstream" and similar terms refer to a direction closer to a bottom/end of a wellbore. Additionally, the team "proximal" refers to a location, an element, or a portion of an element that is further above with respect to another location, element, or portion of the element, while the term "distal" refers to a location, an element, or a portion of an element, that is further below of another location, element, or portion of the element.

Fig. 1 is an illustration of a wellbore instrumentation using the assembly and method according to certain embodiments of the present invention. In Fig. 1, a wellbore extends from the ground surface 4 downwards, forming a substantially vertical part, and then a substantially horizontal part, so is in general a "L"-shape wellbore. In an example, heating by heaters is performed in the horizontal part.

In the wellbore, it can be seen that a casing 51 is provided to receive the coiled tube 54, an artificial lift (e.g. an electrical submerged pump, not shown), the production tubing 52, etc. The coil tubing 54 extends downstream the production tubing 52, the crossover therebetween is done in section 56, which will be further described in details below. Sectional views of different parts of the instrumentation are illustrated in Figs. 12a- 12g, which will also provide more details of the embodiments of the present invention.

To run a heater downstream of pump, according to certain embodiments of the invention, MI cables and instrument strings are assembled inside coiled tubing 54 which is then installed into the wellbore (ahead of the pump and the production tubing 52). Using coiled This allows for a faster deployment and reduces the risk of getting hung up, because there is a smooth surface in the lateral that does not have cables and clamps strapped to it trying to be deployed. The coiled tubing is e.g. the type described in US patent No. 6015015.

Fig. 2 illustrates an enlarged view of section 58 of the wellbore instrumentation shown in Fig. 1. As indicated, the transition/crossover between the coiled tubing 54 and the production tubing 52 happens in section 56. Examining section 58 from right hand side to left hand side, it can be seen that: an end termination 40 of the coiled tubing 40, the coiled tubing 54 in which MI cables and instrument strings are installed to heat the formation around, a transition from coiled tubing 54 to production tubing 52 in section 56 where, with the aid of an assembly as proposed in this present invention, MI cables and instrument strings are taken out of the coiled tubing 54 and strapped to an exterior surface of the production tubing 52 for the remaining distance from the downhole location (e.g. roughly from section 56 and along path 53) to the wellhead at the ground surface 4.

Fig. 3 is an explosive view showing the assembly for downhole deployment of well instrumentation according to an embodiment of the present invention. Figs. 4-11 illustrate a process of installing the assembly according to certain embodiments of the present invention. In this example, the heater includes 2 MI cables 20a and 20b, those skilled in the art would appreciate that different number of MI cables might be used according to needs. Typically, the assembly is installed where a transition from coiled tubing 54 (for heating) to production tubing (for production) is needed.

In the deployment, a lower part of MI cables 20a and 20b, a lower part of instrument strings 22 are inserted inside coiled tubing, which is then installed inside the wellbore, ahead of e.g. the pump, the production tubing 52.

After then, referring to Fig. 4, at the ground surface or near the wellhead, a coiled tubing connector 36 is connected to and above the coiled tubing 54 (not shown). The coiled tubing connector 36 allows the engineers to install the proposed assembly 3. A lower connector 32 is connected to and above the coiled tubing connector 36, with an adjusting nut 34 preferably in between. In this example, the connectors are substantially cylindrical, and the exposed MI cables 20 and the instrument strings 22 can pass through.

A rubber seal 30 is provided, having through holes sized according to diameter of the MI cables 20 and the instrument strings 22. In Fig. 4, it can be seen that instrument strings 22 are inserted through the seal 30. In an example, the instrument strings 22 include fibre optic cable, sensor cable and thermocouple cables. In this step, a screw driver might be useful.

In Fig. 5, MI cables 20a and 20b are opened like a "V" until the rubber seal 30 is between them. Through holes 302 on the seal 30 is prepared for the MI cables. In an example, each MI cable might be provided with one through hole. It can also be seen that clamps 222 might be used to tie up those instrument strings 22 below the seal 30.

MI cables 20a and 20b might then be put through the through holes on the seal 30, as illustrated in Fig. 6. While inserting the MI cables and the instrument strings care must be taken to avoid damaging the rubber seal 30. After the installation, it will become clearer that the seal 30 will be able to prevent formation fluids from entering the coiled tubing 54 downstream this assembly.

In Fig. 7, a splitted hanger 31 is used, which has a first part 31a and a second part 31b, connectable to each other via e.g. alien screws 33. An inner side of hanger 31 is designed for the purpose of restricting the movement of the MI cables 20a and 20b due to thermal expansion and/or contraction. An inner side of the hanger 31 may be also provided with grooves for the instrument strings 22. The hanger 31 is designed to be installed above the seal 30.

An end cap 35 having a first part 35a and a second part 35b is also provided, to be installed below the seal 30. A set of alien screws 37 are provided to fasten and fix the end cap 35 to the splitted hanger 31 via the rubber seal 30. An inner side of the end cap 35 may have grooves to adaptively receive the MI cables and instrument strings.

After installation described with reference to Figs. 4-7, an assembly 3 as illustrated in Fig. 8 can be obtained, including the splitted hanger 31, the rubber seal 30 and the end cap 35, serially connected. Those skilled in the art would appreciate that after at least partially placing the assembly 3 inside the lower connector 32, formation fluid will not be able to flow downward to the coiled tubing 54, as further illustrated in Fig. 9.

In Fig. 9, MI cables 20a and 20b are separated to form a "V" shape, to allow an upper connector enter and fit.

In Fig. 10, the upper connector 38 is provided, its lower end 382 has screw thread connectable with the adjusting nut 34. The upper connector 38 is let down until it touches the top of the splitted hanger 31. The screw thread might have interruptions to allow the MI cables 20a, 20b and the instrument strings 22 to get out.

In Fig. 11, the adjusting nut 34 is moved up to screw with the upper connector 38. After then, the assembly is securely installed to the system. Referring to Fig. 3, the fixing nut 34 can have a flange 342 extruding radially inward, and the lower connector can have a flange 322 extruding radially outward, thereby fix the whole set.

Figs. 12a- 12g illustrate section views of the wellbore instrumentation in Figs. 1-2. Referring to Figs. 12c-e, the transition from coiled tubing 54 to production tubing 52 can be clearly seen.

In an embodiment of the invention, MI downhole hanger assembly designed to support MI cables and instrument strings above a coiled tubing string. The hanger assembly is attached to a (threaded) coiled tubing connector after the coiled tubing is deployed downhole. The assembly provides the seals for each of the MI cables and instrument strings to prevent any wellbore fluids from entering the coiled tubing assembly. In addition, this assembly provides means for the transition of the MI cables and instrument strings installed inside the coiled tubing string from the interior to the exterior of the MI downhole hanger assembly. This allows for the MI cables and instrument strings to be strapped onto the exterior of the production tubing for the remaining distance from the downhole location to the wellhead at the surface. Additionally, the MI downhole hanger assembly provides for the necessary crossover from the coiled tubing assembly to the production tubing and allows the coiled tubing assembly to be attached to the production string below the intake of the production pump.

The present disclosure is not limited to the embodiments as described above and the appended claims. Many modifications are conceivable and features of respective embodiments may be combined.

The following examples of certain aspects of some embodiments are given to facilitate a better understanding of the present invention. In no way should these examples be read to limit, or define, the scope of the invention.

It is to be understood the invention is not limited to particular systems described which may, of course, vary. It is also to be understood that the

terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the content clearly indicates otherwise. Thus, for example, reference to "a core" includes a combination of two or more cores and reference to "a material" includes mixtures of materials. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.