WO2020261197A1

WO2020261197A1 - Method for drilling and lining a wellbore

Info

Publication number: WO2020261197A1
Application number: PCT/IB2020/056055
Authority: WO
Inventors: Sébastian Daniel Jean DESMETTE
Original assignee: Diamant Drilling Services S.A.
Priority date: 2019-06-28
Filing date: 2020-06-26
Publication date: 2020-12-30

Abstract

Method for drilling a wellbore (1) with a constant diameter, wherein is provided a drilling device and several unexpanded casing sections (5), wherein the drilling device is suspended by a cable (2) and comprises a drilling tool and an expansion system to install and to expand the unexpanded casing sections (5), characterized in that for drilling and lining a section the following steps are performed:a) a said unexpanded casing section (5) is connected to the drilling device,b) the drilling tool drills a section and the cuttings are collected,c) the unexpanded casing section (5) is installed in place and expanded by the expansion system, d) the drilling device is tripped up to the surface and the cuttings are downloaded.

Description

METHOD FOR DRILLING AND LINING A WELLBORE

This invention concerns a method for drilling and lining a wellbore with a constant diameter, wherein is provided a drilling device and several unexpanded casing sections, wherein the drilling device is suspended by a cable and comprises a drilling tool to drill successive sections of the wellbore and an expansion system to line the successive sections.

This invention also concerns a drilling device for performing such a method.

With such a method, wellbores having a constant diameter, regardless of their depth/length, can be made. Such wellbores are among others used in the oil and gas industry and for geothermal applications.

Drilling a wellbore of several thousand metres, requires the installation of casing to maintain the wellbore walls. This to avoid contaminating of the various geological layers and the groundwater, to isolate the wellbore from geological fluids, and to control pressures during drilling and maintenance operations. Existing methods for drilling and lining a wellbore consist of drilling a first section from the surface, then placing a casing and then drilling another section followed by placing a casing and so on. These existing methods all use complex drilling systems such as drilling systems comprising a drilling rig, drilling devices with complex cuttings removal elements and/or a high-power hydraulic systems to inject drilling fluid from the surface to the bottom of the already drilled wellbore and this among others to evacuate the cuttings to the surface, and to possibly modify the composition of the drilling fluid according to the drilling needs.

In EP 1702133 a drilling device is described which is suspended by cable, comprising an upper and lower length of the cable connected by cable connecting means, wherein the drilling device comprises a drilling tool and an expansion system and means to pump the cuttings to the surface. This is rather a complex system. Also to install the casing, an unexpanded casing needs to be lowered from the cable to the drilling device and this by disconnecting the cable connecting means of the upper and lower lengths of the cable, such to place the unexpanded casing around the cable. This is cumbersome.

WO 2004/070159 describes a casing drilling device of which parts of the drilling device may be retrieved from the surface and this after all the drilling and lining has taken place. The device is attached to the casing string which is used to drill the hole. This device uses flow circulation from the surface to bring the cuttings to the surface. Drilling with casing is a method that requires the casing to be placed from the surface to the end of the section drilled. If one wants to drill a subsequent section, it has to insert a telescopic casing string from the surface, within the previous casing string. Extending the casing with the same diameter is not possible with the drilling casing method. This is also rather a complex system.

Drilling and lining of wellbores using existing methods , such as the methods described in EP 1702133 and WO 2004/070159, is thus cumbersome and expensive. The result of this is that for geothermal applications, the drilling cost is often prohibitive.

It is therefore an object of the invention to provide a method for drilling and lining a wellbore which is less complex and less expensive, such that the drilling costs for a wellbore are more acceptable.

This object is achieved by providing a method for drilling and lining a wellbore with a constant diameter as described in paragraph 1 of page 1 of this description, wherein for drilling and lining a section the following steps are performed:

a) a said unexpanded casing section is connected to the drilling device,

b) the drilling tool drills a section and cuttings are collected,

c) the expansion system lines the drilled section by expanding the unexpanded casing section,

d) the drilling device is tripped up to the surface and the cuttings are downloaded, and in that for drilling and lining a consecutive section the abovementioned steps are repeated and the drilling device is tripped down into the last drilled and lined section and that the step a is performed before the drilling device is tripped down and the steps b, c and d are performed after the drilling device is tripped down.

By using a drilling device which is suspended by a cable, the installation of a complex drilling rig on the surface can be avoided. Everything the drilling device needs, such as energy, can be supplied by the cable. Also by using a drilling device that is capable of both drilling a section and lining a section, one only has to provide one device. In this method cuttings, which are generated by drilling a said section, are collected and are downloaded on the surface after the drilling device is tripped up, such that one does not need to provide an expensive pumping system or similar, to pump the cuttings to the surface. By collecting the cuttings before tripping down again, the drilling device is free from cuttings while it is tripped down, such that the tripping down can performed in an easy and fast manner.

This method requires a significant less complex drilling device than the drilling device needed for already existing methods and this method is also easily executable such that the drilling costs for drilling a wellbore are significantly reduced with the aid of this method. It is therefore possible to drill wellbores even for geothermal applications.

Here the unexpanded casing section can be easily brought to the desired location in the drilled section, because it gets transported by the drilling device itself. When the drilling device is tripped down into the last drilled and lined section, the unexpanded casing section can be further transported while the drilling tool drills the consecutive section such that the unexpanded casing section is immediately in place after the drilling is done. If the expansion system comprises a casing section positioning system, then this casing positioning system only has to place the unexpanded casing section in the correct position, after which the expansion of the unexpanded casing can begin. However it is also possible that the unexpanded casing section remains in the last drilled and lined section while the drilling tool drills the consecutive section. The unexpanded casing section is then picked up after the drilling of the consecutive section and installed in place such that it can be expanded. One can easily connect an unexpanded casing section to the drilling device since the drilling device is tripped up after the drilling and lining of a section, such that the drilling device is then located at the surface and easily accessible for attaching an unexpanded casing section to the drilling device. One can for example trip the drilling device up in such a way that the entire drilling device is located above the surface, such that unexpanded casing section can be attached to the drilling device from below. Here the cable does not hinder the connection of an unexpanded casing section to the drilling device. The drilling tool can have a drill head comprising a least one removable part or a drill head comprising at least one retractable part such that the unexpanded casing section can be easily connected to the drilling device from below in such a way that the unexpanded casing section surrounds for example at least a part of the drilling device. In an alternative embodiment, the unexpanded casing section can be attached to the drilling device from above. This is possible when the drilling device is releasably connected to the cable in an easy manner with the aid of cable connection elements which are situated at the height of the top of the drilling device. One can then simply disconnect the cable connecting means and attach an unexpanded casing section to the drilling device from above.

Preferably this method is used for drilling a substantially vertical wellbore. The first section that is drilled is then drilled from the surface and the drilling device is then successively tripped down and tripped up. Tripping down means the lowering down of the drilling device in the already drilled and lined (successive) section(s). Tripping up means the recovery of the drilling device from the already drilled and lined (successive) section(s) up to the surface. For drilling vertical wellbores no additional tractor device is required. For drilling horizontal wellbores, preferably a tractor device is provided such as to assist the horizontal movement of the drilling device. The drilling device can be a wireline drilling device. In a preferred embodiment the drilling device comprises a compartment for collecting cuttings and in step b the cuttings are collected in the compartment. The drilling device can then have a cutting removal system to remove and store the cuttings in the said compartment. This compartment can be a kind of basket and the cutting removal system can comprise simple elements, such as for example a rotatable screw member, to transport the cuttings to the compartment since the cutting removal system only has to transport the cuttings to the compartment and thus not directly to the surface. By storing the cuttings in the said compartment, the drilling device can be easily tripped up and also the collecting of the cuttings at the surface can be done in an efficient and easy manner. When the cuttings are downloaded and the drilling device is tripped down again, the compartment is empty such that there are no or almost no cuttings that can hinder the tripping down of the drilling device. Drilling fluid can then easily pass through the compartment during the tripping down. Preferably, the cuttings are directly packed into a bag or a tube in the said compartment in order to easily remove the cuttings after the drilling device has been tripped up to the surface. For this, an empty bag or tube is placed into the compartment before the drilling the device is tripped down to drill and line a consecutive section.

In an alternative embodiment the cuttings can also be collected above the drilling device, wherein the cuttings are then tripped up by tripping up the drilling device.

Preferably the drilling device is tripped up and down with the aid of the cable. The drilling device here is suspended from a cable that extends from the surface such that with the aid of the cable the drilling device can be easily tripped up to the surface and tripped down from the surface. This cable can only be used for tripping up and down the drilling device, but preferably this cable also provides energy to the drilling device and in a specific embodiment this cable can also be an umbilical cable which for example further provides drilling fluid to the drilling device. To trip the drilling device up and down with the aid of the cable, preferably cable traction means are used. These cable traction means are then preferably installed on the surface. These cable traction means can be very simple. For example, they can comprise one or several pulleys, a cable reel and a simple motor to rotate the cable reel. An expensive drilling rig is not required for such a cable.

In a preferred embodiment the cable provides energy to the drilling device. For example, the cable can provide energy to the drilling tool and/or to the expansion system. This energy can be electrical energy and/or hydraulically energy. The advantage here is that the drilling device itself can receive all the necessary energy from the cable, such that there is no need for a complex drilling rig. Also because the energy is provided through the cable, the drilling device does not need batteries are something similar, such that the volume of the drilling device can be kept reasonable and one does not need to worry about the temperature at the height of the drilling.

Further preferably, the drilling tool comprises a motor and a drill head which is driven by the motor, wherein the cable provides energy to the motor. This motor can be an electric motor or a hydraulic motor.

Preferably a said unexpanded casing section is placed around at least a part of the drilling device for connecting the unexpanded casing section to the drilling device. The unexpanded casing section is then placed in such a way that the said unexpanded casing section surrounds at least a part of the drilling device. The diameter of the outer surface of the unexpanded casing section is such that it is smaller than the diameter of the already drilled and lined sections such that the drilling device can be easily tripped down.

During the drilling and lining of a consecutive section, the drilling device preferably relies on the previous drilled and lined section. The drilling section thus takes support upon an already installed expanded casing section. This means that during the drilling of the consecutive section, the drilling tool can rely on the previous drilled and lined section and that during the expansion the unexpanded casing section, the expansion system can rely on the previous drilled and lined section. More preferably, during the drilling and lining of a consecutive section, at the level where the drilling device is based / relies on the previous drilled and lined section, the drilling device seals the space between the drilling device and the previous drilled and lined section. The result is that a seal is created. This increases well control and helps manage pressure. In fact, if a formation fluid is released during drilling, it is controlled by means of this seal. This prevents the fluid from rising higher in the well, and in particular up to the surface. The formation fluid can be a liquid, such as water or oil or gas. The drilling device can optionally allow the fluid to pass in a controlled manner in order to gradually and in a controlled manner reduce the pressure originating from the arrival of the fluid.

In a specific embodiment the drilling tool is a core drilling tool and, during the drilling of a said section, core is collected and this core is downloaded after the drilling device is tripped up to the surface. In this embodiment, the amount of cuttings that is generated and which has to be collected is highly decreased. In addition, the core can provide interesting information about the drilling of the wellbore as it progresses. For example, one can see the composition of the formation and one can see when said composition changes.

Preferably, before the connection of a said unexpanded casing section to the drilling device, the drilling device is checked for defects. The checking for defects can be performed very thoroughly. The checking for defects can also be done quickly, for example a quick visible inspection should also be seen as checking for defects. The checking for defects can be done with the aid of a schedule. For example, one can do several quick and less thorough inspections followed by a thorough inspection that is again followed by several quick and less thorough inspections. Because the drilling device is tripped up to the surface, defects can be quickly detected. This is specifically important for elements of the drilling device which wear out quickly, such as elements that come into direct contact with the formation during the drilling. These elements are for example the drilling head, reamer arms, ...Because the drilling device is tripped up to the surface after drilling and lining of one section, it is also possible to change the drilling head, the reamer arms or other elements of the drilling device, such that these can be changed when the formation changes or when they are broken.

In a preferred embodiment the drilling device comprises a reservoir for sealing material, and in that during the lining of the drilled section, a said unexpanded casing section expands and gets sealed to the material which surrounds the drilled section, with the aid of the sealing material. The sealing material can for example be concrete or a chemical adhesive. The wellbore is drilled in the ground. The material which surrounds the drilled section is thus the material of the said ground at the height of the drilled section. This can be (solid) rock, soil material or ... By connecting the expanded casing section to the said material, thus to for example the rock material, it is better ensured that the different expanded casing sections will stay in place and thus the wellbore is more stable.

In a specific embodiment a swellable material is attached to the unexpanded casing section before tripping down the drilling device and this swellable material swells up during or after the expansion of the unexpanded casing section, such the expanded casing section is sealed to the material which surrounds the drilled section and to the previous expanded casing section at the height of the overlap. This swellable material will here adhere to the material which surrounds the drilled section, thus to for example the rock, such that a stable and sealed wellbore is obtained.

Preferably the wellbore is a vertical extending wellbore and also preferably each drilled section has a dimension of between 1 m and 50 m and specifically between 8 m and 50 m, according to the vertical direction.

The expansion system preferably comprises a casing section positioning system, one or several expanders and a casing section leakage control system.

In a preferred embodiment one or more sensors are connected to the drilling device and a monitor device is provided which is in contact with the sensors, to monitor the drilling and lining of the wellbore. The monitor device is preferably installed on the surface such that the drilling and lining of the wellbore can be monitored on the surface by for example an operator. As all of the operations are done downhole and with a drilling device that is connected to the surface with aid of a cable, several sensors can be connected to the drilling device to monitor from for example the surface, the different steps during the drilling and lining of the wellbore. These sensors can be pressure sensors, displacement sensors, proximity sensors, force sensors, rotation sensors, flowmeter sensors, strain gauge sensors, tension sensors, electric current sensors, gamma ray sensors, sonic sensors, resistivity sensors, vibration sensors, orientation sensors, caliper sensors, and so on and this to monitor among others the drilling process, cutting collection process, the lining process, the expansion process. The information obtained by the sensors can be provided to the monitor device with the aid of the cable. The cable is then also a data connection cable which provides data from the sensors to the monitor device. Preferably this cable then also provides energy to the drilling device. Here the method is well observed at all times, such that this method can be performed in optimal conditions. The observations can be done by an operator and/or a computer and interventions/adaptations/decisions can be done in real-time.

In a specific embodiment the drilling device comprises a directional system to drill and line a consecutive section from a previous drilled and lined section at the desired angle with regard to the previous drilled and lined section. Here it is possible to reach a specific target, since it is possible to change the direction of the drilled wellbore during the drilling of the wellbore. It is also possible to change slowly from a vertical direction to a horizontal direction or vice versa.

The object of the invention is also obtained by providing a drilling device for performing the abovementioned method.

The present invention is now explained in greater detail below with reference to the following detailed description of some preferred embodiments of a method and a drilling device according to the invention. The aim of this description is solely to give illustrative examples and indicate further advantages and particularities and thus cannot be interpreted as a limitation of the field of application of the invention or of the patent rights claimed in the claims.

In this detailed description, reference is made by means of reference numerals to the appended figures, wherein

-figure 1 shows a section of the top of a drilling device according to the invention, the drilling device extending through a previous drilled and lined section;

-figure 2 shows a schematic overview of six consecutive steps during the drilling and lining of a wellbore section according to a method according to the invention.

The drilling device is used to drill and line a vertical extending wellbore (1) from a surface. The drilling device comprises among others a drilling tool and an expansion system. The drilling device is suspended by a cable (2) and can thus be indicated as a wireline drilling device. The drilling tool comprises among others a removable drill head (3), a compartment (6) for collecting cuttings and/or core, a motor (7), wherein the drill head (3) is driven by the motor (7), reamer arms (9) for enlarging the diameter of the sections during the drilling of these sections and supporting elements (8). The cable (2) provides energy to the motor (7). The expansion system comprises a casing section positioning system, expanders (4) and a casing section leakage control system.

The drilling and lining of a wellbore (1) is performed as follows:

First an unexpanded casing section (5) is connected to the drilling device. Figure 1 shows a drilling device with an unexpanded casing section (5) connected to it. Then the drilling tool will drill a section. The drilling device will rely upon an already drilled and lined section for drilling the consecutive section and expanding the unexpanded casing section (5) and this with the aid of the supporting elements (8). This is shown in steps 1 and 2 of figure 2. As can be seen in figure 2 the unexpanded casing section (5) is transported with the drilling tool as the drilling tool drills the section. This means that the unexpanded casing section (5) is already in place immediately after the drilling of the said section is done. During the drilling of the section, cuttings and possibly the core, depending on the type of drilling device, are collected in the compartment (6) of the drilling tool. The reamer arms (9) are in their opened up position such that the drilled section gets the desired diameter such that the unexpanded casing section (5) can be expanded. When the drilling of the section is done, the casing section positioning system positions the unexpanded casing section (5) in the desired position, after which the expanders (4) expand the unexpanded casing section (5) and this during the retrieval of the drilling device out of the said last drilled section. This can clearly be seen in steps 3 to 6 of figure 2. During the retrieval of the drilling device, the reamer arms (9) are in their retracted position. Every unexpanded casing section (5) has swellable material attached to its outer surface such that during the retrieval of the drilling device and the expansion of said casing section (5), the expanding casing section gets connected to the material which surrounds the drilled section with the aid of said swellable material. After the expansion of the casing section, the drilling device is tripped up to the surface with the aid of the cable (2) and the cuttings and possibly the core are downloaded from the compartment (6). The drilling device is checked for defects, this in quick or a thorough manner, and another unexpanded casing section (5) is connected to the drilling device and the drilling device is tripped down into the already drilled and lined section(s) such that the abovementioned steps can be repeated and another section can be drilled and lined.

Claims

C L A I M S

1. Method for drilling and lining a wellbore (1) with a constant diameter, wherein is provided a drilling device and several unexpanded casing sections (5), wherein the drilling device is suspended by a cable (2) and comprises a drilling tool to drill successive sections of the wellbore (1) and an expansion system to line the successive sections, characterized in that for drilling and lining a section the following steps are performed:

a) a said unexpanded casing section (5) is connected to the drilling device, b) the drilling tool drills a section and cuttings are collected,

c) the expansion system lines the drilled section by expanding the unexpanded casing section (5),

d) the drilling device is tripped up to the surface and the cuttings are downloaded,

and in that for drilling and lining a consecutive section the abovementioned steps are repeated and the drilling device is tripped down into the last drilled and lined section and that the step a is performed before the drilling device is tripped down and the steps b, c and d are performed after the drilling device is tripped down.

2. Method according to claim 1, characterized in that the drilling device comprises a compartment (6) for collecting cuttings and that in step b the cuttings are collected in the compartment (6).

3. Method according to claim 1 or 2, characterized in that the drilling device is tripped up and down with the aid of the cable (2).

4. Method according to any of the preceding claims, characterized in that the cable (2) provides energy to the drilling device.

5. Method according to claim 4, characterized in that the drilling tool comprises a motor (7) and a drill head (3) which is driven by the motor (7), wherein the cable (2) provides energy to the motor (7).

6. Method according to any of the preceding claims, characterized in that the unexpanded casing section (5) is placed around at least a part of the drilling device for connecting the unexpanded casing section (5) to the drilling device.

7. Method according to any of the preceding claims, characterised in that during the drilling and lining of a consecutive section, the drilling device relies on the previous drilled and lined section.

8. Method according to claim 7, characterized in that during the drilling and lining of a consecutive section, at the level where the drilling device relies on the previous drilled and lined section, the drilling device seals the space between the drilling device and the previous drilled and lined section.

9. Method according to any of the preceding claims, characterized in that the drilling tool is a core drilling tool and that, during the drilling of a said section, core is collected and this core is downloaded after the drilling device is tripped up to the surface.

10. Method according to any of the preceding claims, characterized in that before the connection of a said unexpanded casing section (5) to the drilling device, the drilling device is checked for defects.

11. Method according to any of the preceding claims, characterized in that the drilling device comprises a reservoir for sealing material, and in that during the lining of the drilled section, a said unexpanded casing section (5) expands and gets sealed to the material which surrounds the drilled section, with the aid of the sealing material.

12. Method according to any of the preceding claims, characterized in that a swellable material is attached to the unexpanded casing section (5) before tripping down the drilling device and this swellable material swells up during or after the expansion of the unexpanded casing section (5), such that the expanded casing section (5) is sealed to the material which surrounds the drilled section.

13. Method according to any of the preceding claims, characterized in that the wellbore (1) is a vertical extending wellbore (1).

14. Method according to any of the preceding claims, characterized in that each drilled section has a dimension of between 1 m and 50 m according to the vertical direction.

15. Method according to any of the preceding claims, characterised in that the expansion system comprises a casing section positioning system, one or several expanders (4) and a casing section leakage control system.

16. Method according to any of the preceding claims, characterised in that one or more sensors are connected to the drilling device and a monitor device is provided which is in contact with the sensors, to monitor the drilling and lining of the wellbore.

17. Method according to any of the preceding claims, characterized in that the drilling device comprises a directional system to drill and line a consecutive section from a previous drilled and lined section at the desired angle with regard to the previous drilled and lined section.

18. A drilling device for performing the method according to any of the claims 1 to 17.