Core drilling equipment and methods for switching between core drilling assemblies and full-diameter drilling assemblies.

Abstract

A core drilling apparatus suitable for switching between a core drilling assembly and a full-diameter drilling assembly, and a method for achieving this. The apparatus includes a coring bit (200), an outer tube (210) for transmitting force to the bit (200), an inner tube (220) having an upper end connected to a lifting device (230) and a lower end adapted to receive a core sample, a conveying device (240) connected to the upper end of the outer tube (210), and wherein the lifting device (230) is adapted to operate between upper and lower positions within the outer tube (210). The coring bit (200) includes a closure element (201) with an integrated cutting tool, which, when in a closed or partially closed position, enables the bit (200) to operate in full-diameter drilling operation, and, when the closure element (201) is in an open position, enables the bit (200) to operate as a coring bit by introducing a rock sample into the inner tube (220). The lifting device (230) includes a release mechanism that, when activated, releases the force acting on the lifting device (230) such that when the lifting device (230) is in the upper position when activated, the lifting device (230) lowers the inner tube (220) to push the closing element (201) to the open position, and when the lifting device (230) is in the lower position when activated, the lifting device (230) raises the inner tube (220) from the closing element (201) such that the closing element (201) is in the closed or partially closed position.

Description

Technical Field

[0001] The present invention generally relates to the extraction of core samples from underground rock formations, and more specifically, to a combined coring and drilling apparatus that provides the option to collect core samples without collecting additional sample material or to drill forward and do so without performing tripping operations. Background Technology

[0002] Core samples have been extracted from boreholes since the earliest days of modern oil and gas exploration. French engineer Rodolphe Leschot applied for the first patent in the United States in 1863 for a core-taking drill bit, though primarily for the mining industry. The main purpose of extracting core samples from the subsurface is to obtain detailed information about the geological formations, their physical parameters (such as mineralogical properties and porosity), fluid content, and stratigraphic sequence. Before the invention of wireline logging, core sampling was the primary method for obtaining reliable and detailed information about the subsurface. Laboratory analysis of core samples remains considered the most reliable data source for providing certain types of information required as input data for modern reservoir simulation models.

[0003] Current technologies designed for cutting and extracting core samples from underground strata can be broadly categorized into two types. The first type is coring systems used to extract short (a few inches), small-diameter core samples from the borehole wall (i.e., transverse to the borehole axis). The second type is coring systems that use conventional steel drill strings or wire ropes as a transport method to collect long (up to hundreds of feet) substantially continuous core samples with potentially larger diameters along the longitudinal borehole axis.

[0004] The second type, the most widely used in the industry, requires information about the nature and sequence of geological strata in and around the reservoir area. In its basic form, this type of system would be a single component comprising: a core head, a drill bit used to cut or crush the rock matrix, with a central circular opening to allow a cylindrical core sample to pass through; an outer tube with an outer diameter smaller than the borehole diameter, which delivers the force required to penetrate the rock; and an inner tube with an inner diameter substantially the same as the central opening in the core head, used to collect and hold the core sample. To prevent the core sample from falling out of the inner tube, the lower end, or "shoe," would be equipped with a serrated ring or some other means to hold the sample, known as a "core catcher." The inner tube is typically mounted on a bearing assembly at the upper end to allow the outer tube and / or core head to rotate freely around it, while the inner tube remains largely stationary relative to the rock matrix. Therefore, the core sample itself would be a substantially continuous cylinder of rock, with a diameter the same as the innermost rock section cut from the core head and a length of several hundred feet.

[0005] The length of a core sample is primarily limited by the length of the inner tube and the mechanical strength of the various geological layers penetrated by the core drilling assembly. If the region of interest for further analysis of the core sample exceeds the length of the runnable core tube, or if there are multiple regions of interest, this typically necessitates multiple trips to retrieve the core sample and replace the inner tube, or switching between coring and drilling equipment. This is known as tripping and incurs significant operational costs.

[0006] Figure 1 illustrates a conventional core drilling assembly as known in the industry, including: a core bit 100 with a central circular opening to allow a core sample 150 to pass through; an outer tube 110 for transmitting force to the core bit 100; an inner tube 120 for collecting and holding the core sample 150; a bearing assembly 130 allowing the outer tube 110 to rotate freely about the inner tube 120; and some delivery devices 140, typically drill pipe. Drilling fluid 160 is pumped from the drilling rig on the surface through the drill pipe 140 and transferred to the inner annular space 161 between the inner tube 120 and the outer tube 110. At the core bit 100, the drilling fluid 160 is transferred to a channel 103 in the core bit 100 to exit through a port at the cutting surface of the core bit 100, thus the backflow of the drilling fluid 160 carries the rock cuttings crushed by the core bit 100 back to the surface in the annular space 162 between the outer tube 110 and the borehole wall. Once the entire length of the inner tube 120 has been filled with core sample 150, the inner tube 120 needs to be extracted from the borehole, either by first extracting the entire assembly or by retrieving the inner tube 120 through the drill string using a wireline or other means. If it is not desired to obtain core sample 150 from a specific geological sequence, then the core drilling assembly will need to be extracted from the borehole and replaced with a full-diameter drilling assembly, i.e., a trip-in / trip-out operation must be performed.

[0007] From an operational perspective, it is more effective to be able to continuously collect core samples without being limited by the length of the core tube, thus avoiding core sample collapse or breakage, or to be able to sample only the regions of interest for further analysis on the ground, i.e., to drill the entire cross-section of the borehole in those regions of no interest.

[0008] The applicant's own patent EP 2877676 B1 and patent application PCT / EP2019 / 083974 describe a coring system capable of selective coring or drilling. These publications describe systems for selectively selecting core samples to be retained. Figure 2An example of a special coring bit 200 described in PCT / EP2019 / 083974 is shown, which has a closure device 201 that converts the coring bit into a full-diameter bit, and a lifting device or elevator 230 at the distal end of the assembly for raising and lowering the inner tube 220. Like conventional core drilling assemblies known in the industry, the invention also includes: an outer tube 210; an inner tube 220 for collecting and holding core samples 250; and several conveying devices 240 connected to the upper end of the core drilling assembly, such as standard drill pipe tubing.

[0009] exist Figure 2 In the diagram, the elements of the closure device are shown retracted into the wall of the drill bit 200 housing to allow core samples to enter the inner tube 220 for storage. Ports or openings 202 in the drill bit wall allow cuttings to exit into the borehole annulus, although these openings are primarily closed by the retracted closure device elements during coring. Unlike conventional systems, the bearing assembly 222 for the inner tube may be connected to or be part of the lifting device 230. The lifting device is shown in an extended position such that the end of the inner tube 221 away from the bearing assembly 222 is adjacent to the cutting surface of the coring bit, and the core sample 250 can enter the inner tube unimpeded. Within the coring bit 200, channels 203 direct all or some of the drilling fluid flow to the cutting surface of the coring bit to allow cooling and removal of cuttings, which circulate further upward through the borehole annulus 262.

[0010] This configuration allows the core drilling assembly to switch / convert from standard coring mode (i.e., collecting core sample material in the inner tube of the downhole assembly) to full-diameter drilling mode, where the central opening in the drill bit is closed, and the rock material that would otherwise constitute the core sample is broken up before entering the inner tube, thus allowing additional boreholes to be drilled without using more material to fill the inner tube. PCT / EP2019 / 083974 also discloses the use of a controller device 231 connected to an actuator or similar device. The controller device 231 receives control commands from the onboard processing unit or from the surface drilling rig for controlling the valves and pistons of the hoisting device 230. This solution allows for multiple activation and deactivation of the hoisting device, and thus allows for multiple switches from coring mode to full-diameter drilling mode.

[0011] The solution described in PCT / EP2019 / 083974 requires a complex downhole component that is wired for at least some transmission of power and data, as well as devices for generating power downhole or transmitting power from the surface. Such a solution is unsuitable in certain situations, for example, if the focus is on maintaining low cost, or if downhole temperatures are too high for downhole electronics to operate.

[0012] This application discloses a core drilling device and method for enabling and / or disabling the core drilling device between a core drilling assembly and a full-diameter drilling assembly using purely mechanical and / or hydraulic devices, i.e. without using downhole control electronics and power supply. Summary of the Invention

[0013] This invention discloses an apparatus and method for switching core drilling equipment between a core drilling assembly and a full-diameter drilling assembly, and this is achieved using only mechanical and / or hydraulic means.

[0014] The core drilling equipment includes: a core drill bit; an outer tube for transmitting force to the drill bit; an inner tube having an upper end connected to a lifting device and a lower end adapted to receive core samples; a conveying device connected to the upper end of the outer tube, wherein the lifting device is adapted to operate between an upper position and a lower position within the outer tube.

[0015] The coring bit includes a closure element with an integrated cutting tool that, when in a closed or partially closed position, allows the bit to operate at full diameter, and when the closure element is in an open position, allows the bit to operate as a coring bit by inserting a rock sample into the inner tube.

[0016] The lifting device includes a release mechanism that, when activated, releases the force acting on the lifting device, such that when the lifting device is in the upper position when activated, the lifting device lowers the inner tube, thereby pushing the closing element to the open position, and when the lifting device is in the lower position when activated, the lifting device lifts the inner tube from the closing element, such that the closing element is in the closed or partially closed position.

[0017] In one embodiment, the core drilling equipment includes a channel connecting a hoisting device to a flow of drilling fluid, wherein when a release mechanism is activated, the channel opens, thereby allowing pressure exerted by the circulation of drilling fluid in the channel to act on the hoisting device for raising or lowering the hoisting device.

[0018] In another embodiment, the core drilling equipment includes one or more pre-charged hydraulic chambers connected to a hoisting device, wherein when a release mechanism is activated, a fluid flow is released from the hydraulic chambers, thereby causing pressure exerted by the fluid flow to act on the hoisting device for raising or lowering the hoisting device.

[0019] In yet another embodiment, the core drilling equipment includes one or more compression springs connected to the lifting device, wherein when the release mechanism is activated, mechanical force is released from the springs, thereby causing the pressure applied by the springs to act on the lifting device for raising or lowering the lifting device.

[0020] In one embodiment, the release mechanism includes a ball seat for receiving the ball, which activates the release mechanism when the ball falls.

[0021] In another embodiment, the release mechanism includes a shear pin that is broken when a mechanical force is applied and activates the release mechanism.

[0022] In yet another embodiment, the release mechanism includes a disc that is broken and activated when hydraulic pressure is applied.

[0023] The release mechanism may also include an electronic receiving unit adapted to control an electric valve included in the core drilling equipment upon receiving a signal from the dropped flowable device.

[0024] The invention is also defined by a method for switching core drilling equipment between a core drilling assembly and a full-diameter drilling assembly. The core drilling equipment includes: a coring bit; an outer tube for transmitting force to the bit; an inner tube having an upper end connected to a lifting device and a lower end adapted to receive a core sample; a conveying device connected to the upper end of the outer tube, and wherein the lifting device is adapted to operate between an upper position and a lower position within the outer tube.

[0025] The method includes: lowering a core drilling device into a wellbore, and if the core bit includes a closure element with an integrated cutting tool, the closure element, when in a closed or partially closed position, enables the bit to operate at full diameter, and when the closure element is in an open position, enables the bit to operate as a core bit by allowing a rock sample to enter the inner tube.

[0026] The method further includes: activating a release mechanism included in the lifting device to release the force acting on the lifting device, such that when the lifting device is in the upper position when activated, the lifting device lowers the inner tube to push the closing element to the open position to achieve the core sampling mode, and when the lifting device is in the lower position when activated, the lifting device raises the inner tube from the closing element so that the closing element is in the closed or partially closed position to achieve the drilling mode.

[0027] According to one embodiment of the method, by releasing the force acting on the lifting device, when the release mechanism is activated, the flow channel connecting the lifting device to the drilling fluid flow is opened, so that the pressure applied by the circulation of the drilling fluid in the flow channel acts on the lifting device for raising or lowering the lifting device.

[0028] According to another embodiment of the method, when the release mechanism is activated, pressure exerted by the fluid flow is applied to the lifting device by releasing the force acting on the lifting device through the release of fluid flow from one or more pre-charged hydraulic chambers connected to the lifting device, so as to raise or lower the lifting device.

[0029] According to another embodiment of the method, when the release mechanism is activated, one or more compression springs connected to the lifting device are released by releasing the force acting on the lifting device, thereby causing the mechanical force applied by the springs to act on the lifting device for raising or lowering the lifting device.

[0030] According to one embodiment of the method, the release mechanism is activated by dropping the ball onto a ball seat included in the release mechanism.

[0031] According to another embodiment of the method, the release mechanism is activated by destroying a disc included in the release mechanism.

[0032] According to yet another embodiment of the method, the release mechanism is activated by breaking a shear pin included in the release mechanism.

[0033] When a flowable device is detected, the release mechanism can also be activated by causing the flowable device to trigger an electronic receiving unit, wherein the electronic receiving unit is adapted to control an electric valve included in the core drilling equipment.

[0034] All the above-described features of the present invention will be described in detail below with reference to the examples shown in the accompanying drawings. Attached Figure Description

[0035] In the following detailed description, the invention will be explained with reference to the accompanying drawings, which illustrate examples of embodiments of the features of the invention:

[0036] Figure 1 shows a conventional core drilling assembly.

[0037] Figure 2 The features of a core drilling assembly in coring mode are shown.

[0038] Figure 3 An embodiment of a core drilling rig in coring mode is shown, wherein a ball serves as an activation device, and wherein internal circulation of drilling fluid is used to provide force to the lifting device.

[0039] Figure 4 An embodiment of a core drilling rig in drilling mode is shown, wherein a ball serves as an activation device, and wherein internal circulation of drilling fluid is used to provide force to the lifting device.

[0040] Figure 5 An embodiment of a core drilling rig in coring mode is shown, wherein a ball serves as an activation device, and a spring is used to provide force to the lifting device.

[0041] Figure 6 The diagram illustrates the transition of a core drilling rig from drilling mode to coring mode, with a spring used to provide force to the lifting device and a ball used as an activation device.

[0042] Figure 7 An embodiment of a core drilling rig in coring mode is shown, wherein a ball serves as an activation device, and wherein a hydraulic chamber and a piston are used to provide force to the lifting device.

[0043] Figure 8 An embodiment of a core drilling rig in drilling mode is shown, wherein a ball serves as an activation device, and wherein a hydraulic chamber and a piston are used to provide force to the lifting device.

[0044] Figure 9 An embodiment of a core drilling rig in coring mode is shown, wherein a flowable device serves as an activation device for a battery-powered electric valve, and wherein internal circulation of drilling fluid is used to provide force to the lifting device.

[0045] Figure 10 An embodiment of a core drilling rig in drilling mode is shown, wherein a flowable device serves as an activation device for a battery-powered electric valve, and wherein internal circulation of drilling fluid is used to provide force to the lifting device.

[0046] The following attached diagram is used for reference:

[0047] 100 - Core Drill Bit

[0048] 103 - Passage

[0049] 110 - Foreign Management

[0050] 120 - Inner tube

[0051] 130 - Bearing assembly

[0052] 140 - Conveying device

[0053] 150—Core Sample

[0054] 160 — Drilling fluid

[0055] 161—Inner Ring Space

[0056] 162—Drill hole annulus

[0057] 200 - Core Drill Bit

[0058] 201—Closed element

[0059] 202 - Drill bit opening

[0060] 203 - Passage

[0061] 210—External Pipe

[0062] 220 - Inner tube

[0063] 221—Inner tube end

[0064] 222 - Bearing Assembly

[0065] 223 - Lower bearing assembly

[0066] 224 - Upper bearing assembly

[0067] 225 - Bearing

[0068] 226——Small drop ball

[0069] 227 - big drop

[0070] 230 - Lifting device

[0071] 231—Controller device

[0072] 234——Upper Room

[0073] 235 - Lower Room

[0074] 238 - Flow channel

[0075] 240 - Conveying device

[0076] 250—Core sample

[0077] 260 — Drilling fluid

[0078] 261—Internal Circular Space

[0079] 262—Drilling annular space

[0080] 270 - Shear pin

[0081] 271—Spring-loaded shear pin

[0082] 272 - Groove

[0083] 273 - Spring

[0084] 275—Pre-charged hydraulic chamber

[0085] 276 - Valve

[0086] 277 - Piston

[0087] 278 - Battery

[0088] 279—Electronic Unit

[0089] 280—Receiver Unit

[0090] 281—Mobile Device

[0091] 282—Hydraulic Lifting System Detailed Implementation

[0092] To explain the invention in detail, reference is made to the following description of a core drilling apparatus and a method for switching between a core drilling assembly and a full-diameter drilling assembly, in conjunction with the accompanying drawings illustrating examples of embodiments that feature the invention.

[0093] This invention discloses details of core drilling equipment suitable for drilling and coring without tripping operations, and methods for switching between coring and drilling modes. The core drilling equipment can be switched between core drilling assemblies and full-diameter drilling assemblies using purely mechanical and / or hydraulic devices (i.e., without the use of complex downhole control electronics and power supplies).

[0094] The core drilling equipment includes: a core bit; an outer tube for transmitting force to the bit; and an inner tube having an upper end connected to a lifting device and a lower end adapted to receive core samples. It also includes a conveying device connected to the upper end of the outer tube. The lifting device is adapted to operate between an upper position and a lower position within the outer tube and includes a release mechanism that, when activated, releases the force acting on the lifting device, such that when the lifting device is in the upper position, it lowers the inner tube, thereby pushing a closing element to the open position, and when the lifting device is in the lower position, it lifts the inner tube from the closing element, such that the closing element is in the closed or partially closed position.

[0095] The coring bit includes a closure element with an integrated cutting tool that, when in a closed or partially closed position, allows the bit to operate at full diameter, and when the closure element is in an open position, allows the bit to operate as a coring bit by inserting a rock sample into the inner tube.

[0096] By closing or substantially closing the central opening of the coring bit below the inner tube, the rock that entered the central opening of the coring bit will be ground away. By opening the central opening of the coring bit below the inner tube, the rock that entered the central opening of the coring bit will enter the inner tube, making it available for further analysis.

[0097] The central opening is opened or closed by a closure element with an embedded cutting tool for grinding away drilled rock formations when closed. The ground debris or rock fragments are carried to the surface via a port in the drill bit along with the drilling fluid return flow. The port leads to the annular space between the drill bit and the borehole wall.

[0098] The closing element is opened and closed by raising and lowering the inner tube. When the inner tube is lowered, it pushes the closing element downward, thus providing an open passage for coring formation material to enter the inner tube. When the inner tube is raised, it no longer pushes the closing element downward, and a spring or other device connected to the closing element pushes the closing element to the closed position. Details of this mechanism are disclosed in the applicant's own patent application PCT / EP2019 / 083974.

[0099] The solutions disclosed herein describe additional improved features of the apparatus for combined coring and drilling in wellbores disclosed in PCT / EP2019 / 083974, and in particular details of the activation, lifting and lowering mechanism of the lifting device, which enables the lifting and lowering of the inner tube to control the opening and closing of the closing element.

[0100] In its basic form, the present invention includes the above references Figure 2 The main features described in the applicant's own patent application PCT / EP2019 / 083974 include: a special coring bit 200 with a closure device 201 that converts the coring bit into a full-diameter bit; and a lifting device or elevator 230 located at the distal end of the assembly for raising and lowering the inner tube 220. In terms of current industry practice, the invention also includes: an outer tube 210; an inner tube 220 for collecting and holding core samples 250; and some conveying device 240 connected to the upper end of the core drilling assembly, such as a standard drill pipe. However, instead of a complex electronic controller device 231 for switching between coring and drilling modes, the invention provides a non-electrical solution to perform the same function.

[0101] In one configuration, the invention can be set for single-step operation, wherein the downhole assembly is configured to achieve a single transition from drilling mode to coring mode. When the downhole assembly is lowered into the well, the inner casing is in the ascending position, and elements of the closure device (including cutting tools or teeth) extend and engage below the inner casing. The tool is then configured for drilling. This tool configuration can then be switched to coring mode as needed.

[0102] To convert a core drilling assembly from drilling mode to coring mode, and vice versa, the transition from one mode to the other must first be initiated. This initiation can be done by dropping a ball into the drill string or by using other initiation devices as described below. Once the ball or other initiation device is received by the downhole tool, the initiation process begins, thereby releasing the force of an actuation mechanism, such as a loaded spring, a hydraulic chamber, or any other actuation mechanism. Upon releasing the actuation force, the inner tube is lowered or pushed downwards, the internal cutting blades of the coring bit are pushed to one side into their rest position relative to the sides of the inner tube, and the inner tube continues to be pushed downwards to its lowest position, which is suitable for coring. Coring can then begin and continue until the inner tube is filled with core, or the operator decides to interrupt coring. The core drilling equipment and the core can then be pulled out of the borehole and placed on the surface.

[0103] Similarly, the invention can be used in the opposite application: in this case, the device is also configured for single-step operation, but is configured to allow a transition from coring mode to drilling mode. When the inner tube is lowered into the well, the internal cutter of the coring bit retracts to its resting position within the tool wall behind the inner tube, i.e., the tool is configured for coring. This tool configuration can then be switched to drilling mode as needed. This is accomplished by initiating the activation process by dropping a ball into the drill string or any other activation device as previously described. Once the ball or any other suitable activation device is received by the downhole tool, the activation process begins, thereby releasing the force of the actuating mechanism, such as a loading spring or a fluidized hydraulic chamber, or any other actuating mechanism as described later. Upon releasing the actuating force, the inner tube retracts or rises, thereby releasing the internal cutter blades of the device in or near the coring bit from their retracted position, allowing these blades to move into the core path below the inner tube and closing the central opening of the coring bit. When the cutter blades are in the closed position, the downhole assembly is configured for full-diameter drilling. Drilling can then begin and continue as appropriate without having to make a round trip to the ground from the coring unit to the drilling unit.

[0104] In another embodiment, the invention can be configured for a two-step operation: the core drilling equipment is lowered into a borehole configured for full-diameter drilling, and then activated for the first time at an appropriate time to perform a transition from drilling to coring, and then activated a second time to perform a transition from coring back to drilling. Compared to conventional drilling and coring wellbore operations, this eliminates two complete round trips involving changing downhole tools: the first operation is from the drilling assembly to the coring assembly, and the second operation is from the coring assembly back to the drilling assembly. Compared to standard wellbore operations, the first step can be related to the transition from drilling to coring once the core point is reached. Once coring is completed, the second step can be related to the transition from coring back to drilling.

[0105] When the tool is lowered into the well in drilling mode, the inner tubing will be in the raised position, and the closure element of the coring bit will extend and engage below the inner tubing. The tool is then configured for drilling and can be switched to coring mode as needed. This is accomplished by dropping a ball into the drill string or any other activation device as described later, initiating the first activation process. Once the ball or any other suitable activation device is received by the downhole tool, the first activation process begins, thereby releasing the force of an actuation mechanism, which is a loaded spring or a fluid-filled hydraulic chamber or any other actuation mechanism as described later. Upon releasing the actuation force, the inner tubing is lowered or pushed downward, and the closure element of the coring bit is pushed to one side into its rest position behind the inner tubing. The inner tubing continues to be lowered or pushed downward to its lowest position, which will be suitable for coring. Coring can then begin and continue until the inner tubing is filled with core, or the coring process is interrupted for any reason. Instead of pulling the core drilling assembly out of the borehole to lower the core and switch from the coring assembly to the drilling assembly, a second activation step is initiated. This is accomplished by dropping a ball into the drill string or any other second activation device as described later. Once the ball or other activation device is received by the downhole tool, the second activation process begins, thereby releasing the force of the actuation mechanism. Upon releasing the actuation force, the inner tube is lifted or pushed upward, the closing element of the coring bit is released from its retracted position, and is allowed to move into the core path below the inner tube, which will be suitable for drilling. Drilling can then be restarted as appropriate without having to perform a round trip to the surface from the coring assembly to the drilling assembly. Once drilling is complete, the convertible core drilling equipment and the collected core sample can be pulled out of the borehole and placed on the surface.

[0106] Similarly, the invention can be configured in reverse order for two-step operation: the convertible core drilling assembly is lowered into a borehole configured for coring, and then first activated to perform a transition from coring to drilling, followed by a second activation to perform a transition from drilling back to coring. Upon lowering into the borehole, the inner tube is in a lowered position, and the closure element of the coring bit retracts to its resting position within the tool wall behind the inner tube. The tool is then configured for coring. Once the first core section has been cut, the tool configuration can be switched to drilling mode as needed. This is accomplished by initiating a first activation process by dropping a ball into the drill string or any other activation device as described later. Once the ball or any other activation device is received by the downhole tool in due course, the first activation process begins, thereby releasing the force of an actuation mechanism, which is a loaded spring or a fluid-filled hydraulic chamber or any other actuation mechanism as described later. Upon release of the actuation force, the inner tube is lifted or pushed upwards, the coring bit's closing element is released from its retracted position, and it is allowed to move into the core path below the inner tube, converting the equipment to drilling mode. Drilling can then begin as appropriate. Upon reaching the second core sampling point, the equipment can be converted from drilling configuration to coring configuration as needed. This is accomplished by initiating a second activation process, or by dropping a second ball into the drill string, or by any other activation device. Once the ball or other activation device is received by the downhole tool, the second activation process begins, thereby releasing the force of the actuation mechanism, which is a loaded spring or a fluid-filled hydraulic chamber or any other actuation mechanism. Upon release of the actuation force, the inner tube is lowered or pushed downwards, the coring bit's closing element is pushed to one side into its rest position behind the inner tube, and the inner tube continues to be pushed downwards to its lowest position. The equipment is then configured for core sampling, and coring of the second section can begin and continue until the entire inner tube is filled with core, or coring is interrupted for any other reason.

[0107] As can be inferred, the functionality of the invention can be enhanced by including an additional activation mechanism. This can be achieved by dropping a ball of an incremental size corresponding to a ball seat of the same incremental size into the receiver unit of the activation mechanism, or by other means that can operate in incremental steps, or any combination of these methods. In this way, a system can be designed to enable and deactivate the lifting device multiple times.

[0108] The following provides a description of various alternatives to the lifting / lowering mechanism for activating core drilling equipment. The basic idea is based on patent application PCT / EP2019 / 083974, in which electricity is used to displace a valve that opens for drilling fluid flow to pressurize a piston used to lift or lower the inner tube. In one configuration, the flow of drilling fluid in the drill string is used to apply hydraulic pressure to the piston to lift the entire inner tube, thereby opening the space below the inner tube to allow the closing element of a special coring bit to move into the core path and activate the equipment for drilling mode. The reverse operation is also disclosed, again utilizing electric current to displace a valve that opens for drilling fluid flow to apply pressure to the piston in the opposite direction, thus pushing the inner tube downwards to force the cutting element at the lower end of the inner tube into its recessed position and continuing to lower the inner tube until it is in the position for coring. The described method is based on a device having bidirectional communication between the surface control unit and the downhole tool, and on having power generation and electronic processing devices in the downhole tool. On the other hand, the present invention generally does not use such devices for communication, power generation, or electronic processing. One exception is a device described that uses an onboard power source (such as a battery) which is brought in with the tools when it is lowered into the well, and electronic processing to operate the hydraulic hoist, but without the previously patented two-way communication with the ground device, such as that described in patent application PCT / EP2019 / 083974.

[0109] This invention includes an activation mechanism to switch a core drilling apparatus from a configuration for coring operations to a configuration for drilling operations, or vice versa, without primarily using electronic equipment. However, as previously described, in a particular configuration, as described in the final part of the patent specification, the invention is described using an electronic control mechanism operated by a downhole power source, such as a battery. In one embodiment, the core drilling apparatus is configured for single-operation, wherein the apparatus can switch from one operating mode to another once. The described activation method for the lifting mechanism can be incorporated into, or any combination thereof, a device for lifting and lowering the inner casing.

[0110] The following describes various devices for initiating the activation sequence. A conventional method for changing the state of downhole equipment is to drop a steel ball or similar object from the surface. The ball is placed inside the drill string and pumped downhole until it lands in a ball seat within the downhole equipment. The method of dropping the ball from the surface is well known in the art and is commonly used in conventional core drilling operations to initiate the coring process, i.e., to divert drilling fluid flow from inside the inner tube of the core drilling equipment to the annular space between the inner and outer tubes. The principle is that the inner tube is fully opened when the core drilling equipment is lowered into the well, which allows drilling fluid to be pumped through the drill pipe and the core drilling equipment to clean the inner tube before core drilling begins. Subsequently, the ball is dropped from the surface or released from the downhole equipment above the inner tube into the flow path. When the ball lands in the ball seat, it prevents the drilling fluid from flowing through the inner tube and instead forces the drilling fluid into the annular space between the inner and outer tubes, thus enabling the following operating mode: coring can be performed and the core travels into the inner tube, while the drilling fluid provides no resistance and potentially washes away the core sample.

[0111] A similar method can be used to activate the lifting device of the present invention. A ball can be dropped from the ground to land on a ball seat above the inner tube. This then alters the flow of drilling fluid through the tool, diverting all or part of the fluid flow. The diverted portion of the drilling fluid flow passes through a channel that can be guided to a piston, thereby placing hydraulic pressure on the piston. The hydraulic pressure is then used to lift the inner tube. In principle, the energy behind this hydraulic pressure is the pressure difference between the inside and outside of the outer tube at the activation location. By lifting the inner tube, the device's closure element and cutting tool are then allowed access to the space below the inner tube, thus changing the device's configuration from a coring mode with the closure element retracted to a drilling mode with the cutting element activated. This describes a single activation of the device from coring to drilling operation mode.

[0112] It can be inferred that the same activation method can be used to achieve the opposite operation. When the ball falls from the ground to land on the ball seat above the inner tube, the drilling fluid flow through the apparatus is diverted. A portion of the diverted drilling fluid flow passes through a channel that can be guided to the piston, thereby placing hydraulic pressure on the piston and using this hydraulic pressure to push or lower the inner tube downwards. This activation method then forces the device's closing element into the recessed space behind the inner tube by lowering it. The inner tube is then further lowered to its lowest position, thereby changing the configuration of the core drilling equipment from a drilling mode where the cutter element is activated to a coring mode where the cutter element is retracted. This describes a single activation of the equipment from drilling to coring mode.

[0113] Alternative methods can be used to activate the activation mechanism. One such method involves using mechanical force applied from the surface, such as stopping drilling or coring operations by halting the rotation of the drill string and allowing the coring bit to remain at the bottom of the well, and then subsequently applying excessive weight from the surface by lowering the drill string and compressing a device such as a shear pin, thereby releasing the force on the shear pin, which will trigger the activation process. Another method to activate the activation process is to increase the pump speed of the drilling fluid to such an increasing rate that it flows through the tool at an ever-increasing rate until the downhole disc breaks, thereby releasing the force, which will trigger the activation mechanism of the equipment.

[0114] Another alternative to activating a hydraulic hoist is to use a semi-automatic electrically activated method. This method will not rely on a complete downhole instrumentation package with power supply, electronic processing, and two-way communication with surface equipment, as described in patent application PCT / EP2019 / 083974. This alternative electrical device can use a turbine / generator assembly, a battery, or other devices for providing power. It may additionally include a receiver device for receiving activation commands from the surface, such receiver device being capable of receiving information carried by a flowable device dropped to the surface via the drill string, or measuring changes in the drill string in rpm, or measuring changes in applied downhole weight, or changes in mud flow rate, or any other activation command device, or any combination thereof. The activation tool may additionally include electronic processing for controlling the equipment and initiating appropriate actions, and also includes electrically operated valve devices for opening and closing flow guides to release hydraulic pressure from the hydraulic chamber, or electrically operated valve devices for diverting mud flow to guide hydraulic pressure at the piston to raise or lower the core casing, or any other device for opening or closing hydraulic guides to initiate the raising or lowering of the casing assembly.

[0115] A more detailed description of the concept of using flowable devices as means of transmitting information and commands from the surface to downhole tools or from downhole tools to the surface can be found in the patent US 20020185273 A1, "Method of Utilizing Flowable Devices in Wellbores" by Aronstam et al.

[0116] Alternative methods exist for raising or lowering the inner tubing. One such alternative is the use of a spring. This spring is compressed when the core drilling equipment is lowered into the well. As the ball falls and is received at the ball seat, the diverted drilling fluid flow can be used to break the disc or shear pin, or the spring can be released by other means. In one embodiment, the force released by the spring raises the inner tubing and switches the equipment from core drilling mode to core drilling mode, as previously described. In different configurations, the spring will exert a force upon release that lowers the inner tubing, thereby switching the equipment from drilling mode to core drilling mode, as previously described.

[0117] In yet another embodiment, raising or lowering the inner tube can be achieved using a hydraulic chamber. This chamber is pre-filled with compressed fluid before the core drilling equipment is lowered into the borehole. When the ball is dropped and received at the ball seat, the transferred drilling fluid flow can be used to break the disc or shear pin, or to release the hydraulic pressure in the pre-filled chamber via other means. In one configuration, the hydraulic pressure is directed to a piston upon release, which raises the inner tube, switching the equipment from coring mode to drilling mode, as previously described. In another configuration, the hydraulic pressure is directed to a piston upon release, which pushes or lowers the inner tube, switching the equipment from drilling mode to coring mode, as previously described.

[0118] The above descriptions of alternative methods for activating the lifting device for the inner tube all describe a single activation, wherein the core drilling equipment either switches from coring mode to drilling mode or vice versa. These methods can be combined in such a way that the equipment can be configured for dual operation, for example, first switching from coring mode to drilling mode and then back to coring mode, or first switching from drilling mode to coring mode and then back to drilling mode. The activation methods can be further combined to achieve multiple operating modes, thereby enabling the equipment to switch from coring mode to drilling mode and vice versa multiple times.

[0119] A prerequisite for enabling core drilling equipment to switch between coring and drilling modes two or more times is that the activation process can be initiated multiple times. One such method involves dropping steel balls of increased size corresponding to the same size increase in the ball seat, each new and larger ball thus triggering a new and specific sequence of events. Similarly, methods of applying increased weight from the surface can be used to break shear pins with increased strength. Methods using increased drilling fluid flow pumped from the surface can also be used in incremental steps to break disks with increased strength. Furthermore, methods of electrically activated mechanisms are inherently semi-automatic and are activated by commands from the surface by pumping drilling fluid in a specific predetermined sequence, rotating the drill string in a specific predetermined sequence, dropping a flowable device carrying information or commands into the downhole receiver unit within the core drilling equipment, or any combination of the aforementioned activation methods. Finally, the above methods or any other downhole activation methods known in the art can be combined to achieve multiple processes for initiating a particular activation process.

[0120] The following outlines various combinations of activation mechanisms and sources for providing lifting force to the hoisting device. One embodiment of the invention utilizes a combination of transferred drilling fluid flows to raise and lower the inner tube. The method is the same, and as described above, regardless of whether the inner tube is raised or lowered. In one application, activation is first used to switch the device from coring mode to drilling mode, wherein the transferred drilling fluid flow is used to raise the inner tube. As the drilling fluid is pumped down from the surface, it provides a constant pressure on the hydraulic piston and prevents the inner tube from sliding down due to gravity. If the circulation of drilling fluid from the surface facility stops for any reason, the pressure on the hydraulic piston will cease. Therefore, unless the inner tube is locked in place, it can subsequently slide down and force the closing elements in the coring bit back to their retracted positions, thus unintentionally switching the device back to coring mode.

[0121] Therefore, a mechanism is needed to prevent the inner tube from unintentionally sliding downwards during hydraulic pressure removal. This can be achieved at the lower end of the inner tube via a closing element of an interlocking coring bit, thus preventing the inner tube from falling. Alternatively, the same result can be achieved by having one or more shear pins or other similar devices that, once the lifting process has reached its highest position, move into a recess and lock the inner tube lifting mechanism in place. In either case, the strength of the closing element lock or the shear pin must be sufficient to hold the weight of the suspended inner tube. As previously mentioned, the transferred drilling fluid flow system can then be used to lower the inner tube. Thus, it is important that the interlocking strength of the cutting element or the strength of the shear pin can be overcome by force or hydraulic pressure when applied in the opposite direction.

[0122] It should be noted that drilling can be performed without a mechanism to lock the inner casing in its raised position: during drilling, the rock matrix immediately below the closure element in the core bit will prevent the cutting element from retracting. In effect, the bottom of the well will act as a locking mechanism to prevent the inner casing from descending. However, once the entire drill string is raised away from the bottom of the wellbore, this opens the space between the closure element and the underlying rock, and the inner casing can move downwards unless the cutting element is interlocked or the inner casing is locked in the activated position.

[0123] In another embodiment, the activation mechanism uses a spring to raise or lower the inner tube. One or more springs may be installed in the equipment and pre-compressed and in an energized state while being lowered into the well. As previously described, a release mechanism may allow the spring to expand upon activation, thereby raising or lowering the inner tube, depending on its position. When using a spring mechanism, this mechanism may or may not be combined with another mechanism to lock the spring in its extended position. The spring will retain some of its potential energy unless it can fully expand. The spring may be designed to release its energy from an initial fully compressed state to raise the inner tube, thereby enabling a transition from coring mode to drilling mode, and then subsequently remain in a semi-compressed state during drilling, thus maintaining sufficient force to substantially prevent the inner tube from descending due to gravity as the drill string is raised from the bottom of the well.

[0124] In yet another embodiment, the activation mechanism is designed to use a combination of a spring and drilling fluid flow. This combination can be designed in two ways: In a first embodiment, the drilling fluid flow method is used to lift the inner casing, as previously described, to switch the core drilling equipment from coring mode to drilling mode. This is then combined with the spring to lower the inner casing and perform a switchback to coring mode. In an alternative second embodiment, the reverse activation method is used. The spring method is used to lift the inner casing, while the drilling fluid flow method is used to lower it.

[0125] In addition to the above description of using a spring to raise or lower the inner tube in conjunction with the drilling fluid flow method, the spring can also be installed in a non-compressed state without pre-charged energy. The spring activation mechanism is then initially powered using either the drilling fluid flow activation method or the hydraulic chamber activation method. In one embodiment, the drilling fluid flow mechanism is used to first raise the tubing to switch from coring mode to drilling mode. Simultaneously, the spring mechanism is compressed as the inner tube is raised. When the inner core rod has been raised to its highest position, a shear pin or other locking mechanism is activated to prevent the inner core rod from lowering due to gravity, thereby preventing the now compressed spring from being released. The hydraulic chamber activation mechanism will function primarily in the same manner, both raising the inner tube and simultaneously compressing the spring mechanism. Some alternative options utilizing the hydraulic chamber mechanism will be described in more detail later.

[0126] Regardless of which of these embodiments is used, the convertible core drilling rig is typically first used in coring mode. Upon initiating the first activation sequence, drilling fluid flow or hydraulic chambers activate the inner tubing, and the rig now switches to drilling mode. Upon initiating the second activation sequence, the release of spring compression lowers the inner tubing, and a switch back to coring mode is then performed. As previously described, the rig may include additional activation sequences to increase the ability to repeat the following steps: raising the inner tubing using drilling fluid flow and then compressing the spring, followed by the release of spring compression and lowering the tubing. In principle, the first and second activation sequences can be repeated multiple times. When a drilling fluid flow activation mechanism is used in combination with a spring, this can be repeated indefinitely in principle. When using a hydraulic chamber to raise the inner tubing, the number of times this step can be repeated is limited by the number of hydraulic chambers installed in the core drilling rig before it is lowered into the well, as these chambers are pre-energized before installation, unlike drilling fluid flow mechanisms which are energized downhole via drilling fluid flow. However, if a downhole electric activation mechanism is used, there is no limit to the number of times it can be operated.

[0127] In another embodiment, the opposite configuration is used. In this embodiment, the convertible core drilling rig is inserted into the wellbore in drilling mode. Upon initiation of the first activation sequence, drilling fluid flow or hydraulic chamber activation is used to lower the inner tubing, and the rig thus switches to core sampling mode. Upon initiation of the second activation sequence, the release of spring compression force raises the inner tubing, and a switch back to drilling mode is performed. Similarly, the possibility of multiple activation and deactivation sequences can be inferred.

[0128] As previously described, an alternative embodiment utilizes a hydraulic chamber to provide lifting force, rather than relying on the inherent pressure potential of the circulating drilling fluid. The hydraulic chamber is pre-filled with compressed hydraulic fluid, liquid, or gas to a preset pressure.

[0129] A key difference between using hydraulic chambers and drilling fluid flow is that a hydraulic chamber can only be activated and deactivated once, while drilling fluid can be used multiple times using suitable means. Therefore, to allow the invention to be activated and deactivated multiple times using pre-filled hydraulic chambers, multiple hydraulic chambers are required, with an equal number of chambers in the device to match the expected number of activations and deactivations. A core drilling apparatus containing multiple hydraulic chambers for raising or lowering the inner tube is then implemented. Small pressure vessels can be used as hydraulic chambers filled with gas or liquid and pressurized to a suitable preset pressure. Several pressure vessels can be housed in a rotating unit with multiple hydraulic chambers. In one embodiment, when the first hydraulic chamber is activated, the rotating unit containing one or more pressure vessels rotates until the first pressure vessel in the first hydraulic chamber is aligned with the fluid flow path to the piston, and the pressure is subsequently released, and the inner tube is raised or lowered as appropriate. In another embodiment, the hydraulic chamber containing the pressure vessel does not rotate, but a manifold unit at the opening of the hydraulic chamber rotates to align the flow path between the piston and the associated hydraulic chamber when appropriate, thereby subsequently releasing the pressure within the associated pressure vessel and applying the pressure to the piston to raise or lower the inner tube.

[0130] In one embodiment, the hydraulic chamber is used to raise and lower the inner tube. Whether the inner tube is raised or lowered, the method is the same: the potential energy in the pre-charged hydraulic chamber is used to apply hydraulic pressure to a piston, which raises or lowers the inner tube depending on the direction of movement. The hydraulic chamber can also be used in combination with a spring-activated device, in essentially the same way as combining drilling fluid flow with spring activation. In one embodiment, the hydraulic chamber, upon activation, is used to raise the inner tube to switch the equipment from coring mode to drilling mode. Subsequently, the inner tube is lowered using a spring, and the equipment is switched from drilling mode to coring mode. In another embodiment, the hydraulic chamber is used to lower the inner tube, and the spring can then be used to raise the inner tube. Furthermore, the drilling fluid flow method, the hydraulic chamber mechanism, and the spring can be combined and used in any combination to raise or lower the inner tube multiple times.

[0131] Finally, the downhole electric starter can be used to shift electrically operated valves to direct a portion of the drilling fluid flow onto a piston to apply hydraulic pressure, thereby raising or lowering the inner tubing. The downhole electric starter can be used multiple times and in combination with any other method. For example, instead of using a shear pin that cuts by applying weight from the surface or excessive drilling fluid flow rate, this can be a electrically operated shear pin.

[0132] Each of the described activation and enhancement methods will now be explained further with reference to the accompanying drawings.

[0133] Figure 3An embodiment of a core drilling apparatus in coring mode is shown, wherein ball 227 serves as an activation device, and internal circulation of drilling fluid is used to provide force to the lifting device. The apparatus is prepared for activation and conversion to drilling mode, wherein the inner tube 220 extends downwards to a point very close to the drill bit end face of the coring bit 200. An internal closure element 201 in the coring bit 200 is pushed to one side into a recess. A lower bearing assembly 223 with a ball seat for dropping ball 226 is attached to the end of the inner tube 220 away from the coring bit 200. Ball 226 drops at the start of the coring operation, forcing fluid into the internal annular space 261. Bearing 225 allows the lower bearing assembly 223 to rotate relative to the upper bearing assembly 224 to allow the core sample to enter the inner tube 220 with minimal rotational force. To initiate the transition from coring to drilling mode, the larger ball 227 is dropped. As ball 227 remains in the ball seat, the flow of drilling fluid is diverted, and the pressure in the lower chamber 235 increases. The upward force generated in the chamber will break shear pin 270, which was previously designed to prevent the inner cylinder from moving unintentionally upward. Any fluid in the upper chamber 234 can escape through flow channel 238 into the internal annular space 261 of the device. When the bearing assembly with inner cylinder 220 reaches its upper position, the spring-loaded shear pin 271 will lock in the groove 272, preventing the inner cylinder 220 from sliding downward and returning to its initial position.

[0134] Figure 4 An embodiment of a core drilling apparatus in drilling mode is shown, wherein a ball serves as an activation device, and the internal circulation of drilling fluid is used to provide force to the lifting device. In drilling mode, the inner cylinder 220 of the apparatus retracts to a position above the coring bit 200. The internal closing elements 201 in the coring bit 200 have been released from their recessed positions and closed across the central opening of the coring bit 200. To switch the core drilling apparatus from drilling mode to coring mode, the ball 226 is dropped from the ground to land in the ball seat of the lower bearing assembly 223. As the internal flow of drilling fluid is obstructed, the circulation pressure increases, and the shear pin 270 eventually breaks. The bearing assemblies 223, 224 with the inner cylinder 220 are then pushed downwards. As the bearing assemblies are pushed downwards, the connection between the lower bearing assembly 223 and the internal annular space 261 opens, allowing the flow of drilling fluid to transfer into the internal annular space 261 of the core drilling apparatus. Although the downward force of the drilling fluid flow will decrease, the combined hydraulic and gravitational forces will continue to push the inner tube 220 further downward. When the bearing assembly 223 has reached its lowest position, the spring-loaded shear pin 271 will lock into the groove 272, preventing the inner tube 220 from being pushed back upward.

[0135] Figure 5An embodiment of a core drilling apparatus in coring mode is shown, wherein a ball serves as an activation device, and a spring is used to provide force to the lifting device. The apparatus is prepared to perform a transition from coring to drilling mode, wherein the inner tube 220 is pushed downwards until it approaches the end face of the coring bit 200. The internal closure element 201 in the coring bit 200 is pushed to one side into a recess. A lower bearing assembly 223 with a ball seat for dropping a ball 226 is attached to the end of the inner tube 220 away from the coring bit 200. The ball 226 drops to initiate the coring operation and forces fluid into the internal annular space 261. The bearing 225 allows the lower bearing assembly 223 to rotate relative to the upper bearing assembly 224 to allow the core sample to enter the inner tube 220 with minimal rotational force. To initiate the transition from coring to drilling mode, a larger ball 227 is dropped. As the ball 227 remains in the ball seat, the pressure in the lower chamber 235 increases. The resulting upward pressure, combined with the force of the compression spring 273, will break the shear pin 270, which previously prevented the inner cylinder from unintentionally moving upward. When the shear pin 270 breaks, the force of the compression spring is released, and the upper bearing assembly 224 with the inner tube 220 is lifted, allowing the closing element 201 to close the central opening of the core drill bit 200. Any fluid in the upper chamber 234 can escape through the flow channel 238 into the internal annular space 261 of the device. The retaining force of the spring 273 will prevent the inner cylinder from moving downward and return it to its initial position.

[0136] Figure 6 This diagram illustrates the transition of a core drilling rig from drilling mode to coring mode, with a spring providing force to the lifting mechanism and a ball acting as an activation device. The diagram shows three distinct stages during the transition from drilling to coring mode. On the left, the tool is shown in drilling mode. The inner tube 220 retracts above the coring bit 200, and the inner closure element 201 extends and closes across the central opening of the coring bit 200. A shear pin 270 prevents the inner tube 220 from sliding downwards toward the closure element 201. In the middle diagram, the ball 226 drops from the ground to land in the ball seat of the lower bearing assembly 223. As the internal flow of drilling fluid is blocked by the ball 226 in the ball seat, pressure increases, and the shear pin 270 is broken due to the combined force of hydraulic pressure and the compression spring 273. In the right diagram, the shear pin 270 has broken, the force of the compression spring has been released, and the lower bearing assembly 223 has been pushed downwards, aligning with the opening that allows internal drilling fluid to flow into the internal annular space 261 of the equipment. As it moves downward, the inner tube 220 will open the internal closing element 201 of the coring drill bit 200 and eventually stop very close to the drill bit end face, thereby allowing the core sample to enter the inner tube 220, which is consistent with the coring operation mode.

[0137] Figure 7An embodiment of a core drilling apparatus in coring mode is shown, wherein a ball serves as an activation device, and a hydraulic chamber and piston are used to provide force to the lifting device. The core drilling apparatus is prepared to perform a transition from coring to drilling mode, wherein the inner tube 220 is pushed downwards very close to the drill bit end face of the coring bit 200. The internal closure element 201 in the coring bit 200 is pushed to one side into a recess, and the central opening of the coring bit 200 is opened to allow a core sample to enter the inner tube 220. A small ball 226 has been dropped into the ball seat of the lower bearing assembly 223 to divert the internal flow of drilling fluid from inside the inner tube 220 to the internal annular space 261 between the inner and outer tubes. To switch the core drilling apparatus to drilling mode, a second, larger ball 227 has been dropped into the ball seat of the upper bearing assembly 224. Since the internal flow of drilling fluid is now blocked, hydraulic pressure increases and disrupts the disc in valve 276. Therefore, hydraulic fluid can flow out from the pre-charged hydraulic chamber 275 and will flow to the piston 277, which will lift the bearing assemblies 223, 224 with the inner tube 220. When the lowermost end of the inner tube 220 retracts behind the core drill bit 200, the closing element 201 will close the central opening of the core drill bit 200, and the equipment will be ready for full-diameter drilling.

[0138] Figure 8 An embodiment of a core drilling rig in drilling mode is shown, wherein a ball serves as an activation device, and a hydraulic chamber and piston are used to provide force to the lifting device. The core drilling rig is ready to perform a transition from drilling to coring mode. The piston 277, in its extended position, prevents the inner tube 220 from traveling along the axial direction of the rig. The ball 226 has been dropped from the ground and obstructs the internal flow of drilling fluid. As hydraulic pressure from the drilling fluid increases, a disc in valve 276 breaks. Fluid then flows from the pre-charged hydraulic chamber 275 to the piston 277, which retracts and lowers the bearing assemblies 223, 224, and subsequently the inner tube 220 descends to the drill bit face. During descent, the inner tube 220 opens the internal closure element 201 of the coring bit 200 and eventually stops very close to the drill bit face, thereby allowing a core sample to enter the inner tube 220.

[0139] Figure 9 An embodiment of a core drilling rig in coring mode is shown, wherein a flowable device serves as an activation device for a battery-powered electric valve, and wherein internal circulation of drilling fluid is used to provide force to the hoisting device. In this configuration, the activation process is initiated by dropping the flowable device off the surface. The flowable device carries messages or commands continuously transmitted from the device. As the flowable device passes a receiver unit within the downhole tool, the receiver unit picks up the information and initiates the corresponding action.

[0140] The coring drilling equipment is illustrated in coring mode, just before being activated for drilling, with the inner tube 220 extending downwards to the drill bit end face immediately adjacent to the coring bit 200. The internal closure element 201 in the coring bit 200 is pushed to one side into a recess. A lower bearing assembly 223 with a ball seat for a dropped ball 226 is attached to the end of the inner tube 220 away from the coring bit 200. The ball 226 drops to initiate the coring operation and forces fluid into the internal annular space 261.

[0141] To initiate the transition to drilling mode, the flowable device 281 is lowered from the ground. As the flowable device 281 passes the receiver unit 280, the electronic unit 279, powered by the battery 278 or other power source, activates the electrically operated hydraulic valve 276 upon receiving information from the flowable device 281, allowing for the flow and transfer of drilling fluid, and increasing the pressure in the upper chamber 234. The upper chamber 234 is described below. Figure 10 As can be seen, any fluid in the lower chamber 235 can escape into the internal annular space 261 of the device through the flow channel 238. When all the fluid in the lower chamber 235 has been discharged and the bearing assembly 224 with the inner cylinder 220 has reached its upper position, corresponding to the top of the hydraulic lifting system 282 reaching the upper bearing assembly 224, the electrically operated hydraulic valve 276 is activated and switched again to prevent any fluid in the upper chamber 234 from being discharged, thereby preventing the inner cylinder 220 from sliding downward and returning to its initial position.

[0142] As an additional operating device, receiver unit 280 may also be configured to transmit data back to the mobile device 281 and exchange information with it. Such data may include confirmation of receipt of an initial command, as well as other data such as downhole sensor information, electronic equipment status information, and operating parameter information. As is known in the art, the mobile device may then circulate downwards through the internal annular space 261, through the lower part of the core drilling equipment, and back to the surface, whereby the mobile device 281 is collected, and the information contained therein is retrieved by the surface reading unit.

[0143] Figure 10 An embodiment of a core drilling apparatus in drilling mode is shown, wherein the flowable device serves as an activation device for a battery-powered electric valve, and wherein internal circulation of drilling fluid is used to provide force to the lifting device. In drilling mode, the inner tube 220 is retracted to a position above the coring bit 200. The internal closing elements 201 in the coring bit 200 have been released from their recessed positions and closed across the central opening of the coring bit 200. A lower bearing assembly 223 with a ball seat for a dropped ball 226 is attached to the end of the inner tube 220 away from the coring bit 200. The ball 226 drops to initiate the coring operation and forces fluid into the internal annular space 261.

[0144] To initiate the transition of the core drilling equipment from drilling mode to coring mode, the flowable device 281 is dropped from the ground. As the flowable device 281 passes the receiver unit 280, the electronic unit 279, powered by the battery 278 or other power source, activates the electrically operated hydraulic valve 276 upon receiving information from the flowable device 281, allowing the drilling fluid to flow and transfer, and increasing the pressure in the lower chamber 235. The lower chamber 235... Figure 9 As can be seen, any fluid in the upper chamber 234 can escape into the internal annular space 261 of the device through the flow channel 238. When all fluid in the upper chamber 234 has been discharged and the bearing assembly 224 with the inner cylinder 220 has reached its lower position, corresponding to the bottom of the hydraulic lifting system 282 reaching the lower part of the upper bearing assembly 224, the electrically operated hydraulic valve 276 is activated and switched again to prevent any fluid in the lower chamber 235 from escaping, thereby preventing the inner cylinder 220 from being forced upward due to friction from the core sample entering the inner cylinder 220. As described above, the receiver unit 280 can also be configured to transmit data back to the flowable device 281 and exchange information with it.

[0145] The present invention provides a flexible core drilling device that can be converted to operate in coring mode or drilling mode, wherein the transition between modes is enabled and driven by mechanical and / or hydraulic devices.

Claims

1. A core drilling apparatus suitable for switching between a core drilling assembly and a full-diameter drilling assembly, the core drilling apparatus comprising: Core drill bit (200); outer tube (210) for transmitting force to said drill bit (200). An inner tube (220) has an upper end connected to a lifting device (230) and a lower end adapted to receive a core sample; a conveying device (240) is connected to the upper end of the outer tube (210), wherein the lifting device (230) is adapted to operate between an upper position and a lower position within the outer tube (210), characterized in that: - The coring drill bit (200) includes a closure element (201) with an integrated cutting tool, wherein the closure element (201) is operated to close when the lifting device (230) is in the upper position and to open when the lifting device (230) is in the lower position, the drill bit (200) operates at full diameter when the closure element (201) is closed or partially closed, and the drill bit (200) operates as a coring drill bit by allowing a rock sample into the inner tube (220) when the closure element (201) is open; - The lifting device (230) includes a release mechanism that, when activated, releases the force acting on the lifting device (230) to raise or lower the lifting device (230), such that when the lifting device (230) is in the upper position when activated, the lifting device (230) lowers the inner tube (220), thereby pushing the closing element (201) to the open position to achieve the core sampling mode, and when the lifting device (230) is in the lower position when activated, the lifting device (230) raises the inner tube (220) from the closing element (201), such that the closing element (201) is in the closed or partially closed position to achieve the drilling mode.

2. The core drilling equipment according to claim 1, characterized in that: This includes connecting the lifting device (230) to a flow channel (238) for drilling fluid flow, wherein when the release mechanism is activated, the flow channel (238) opens, thereby allowing the fluid force applied by the circulation of drilling fluid in the flow channel (238) to act on the lifting device (230) for lifting or lowering the lifting device.

3. The core drilling equipment according to claim 1, characterized in that: Includes one or more pre-charged hydraulic chambers (275) connected to the lifting device (230), wherein when the release mechanism is activated, fluid is released from the hydraulic chambers (275), thereby causing pressure applied by the fluid to act on the lifting device (230) for raising or lowering the lifting device.

4. The core drilling equipment according to claim 1, characterized in that: Includes one or more compression springs (273) connected to the lifting device (230), wherein when the release mechanism is activated, mechanical force is released from the one or more compression springs (273), thereby causing the force applied by the one or more compression springs (273) to act on the lifting device (230) for raising or lowering the lifting device.

5. The core drilling equipment according to any one of claims 2, 3 or 4, characterized in that: The release mechanism includes a ball seat for receiving the ball, which is activated when the ball falls.

6. The core drilling equipment according to any one of claims 2, 3 or 4, characterized in that: The release mechanism includes a shear pin (270) that is broken when a mechanical force is applied and activates the release mechanism.

7. The core drilling equipment according to claim 3, characterized in that: The release mechanism includes a disc within a valve (276) of the pre-charged hydraulic chamber (275), which is broken when hydraulic pressure is applied and activates the release mechanism.

8. The core drilling equipment according to any one of claims 2, 3 or 4, characterized in that: The release mechanism includes an electronic receiving unit adapted to control an electric valve included in the core drilling assembly upon receiving a signal from a fallen, movable device.

9. A method for switching core drilling equipment between a core drilling assembly and a full-diameter drilling assembly, the core drilling assembly comprising: Core drill bit (200); outer tube (210) for transmitting force to said drill bit (200). An inner tube (220) has an upper end connected to a lifting device (230) and a lower end adapted to receive a core sample; a conveying device (240) is connected to the upper end of the outer tube (210), wherein the lifting device (230) is adapted to operate between an upper position and a lower position within the outer tube (210), characterized in that: - The core drilling equipment is lowered into the wellbore, wherein the core bit (200) includes a closure element (201) with an integrated cutting tool, wherein the closure element (201) is operated to close when the lifting device (230) is in the upper position and to open when the lifting device (230) is in the lower position, wherein the bit (200) operates at full diameter when the closure element (201) is closed or partially closed, and wherein the bit (200) operates as a core bit by allowing a rock sample to enter the inner tube (220) when the closure element (201) is open; - Activate the release mechanism included in the lifting device (230) to release the force acting on the lifting device (230) to raise or lower the lifting device (230), such that when the lifting device (230) is in the upper position when activated, the lifting device (230) lowers the inner tube (220) to push the closing element (201) to the open position to achieve the core sampling mode, and when the lifting device (230) is in the lower position when activated, the lifting device (230) raises the inner tube (220) from the closing element (201) so that the closing element (201) is in the closed or partially closed position to achieve the drilling mode.

10. The method according to claim 9, characterized in that: When the release mechanism is activated, the flow channel (238) connecting the lifting device (230) to the drilling fluid flow is opened, so that the force applied by the circulation of the drilling fluid in the flow channel (238) acts on the lifting device (230) for raising or lowering the lifting device.

11. The method according to claim 9, characterized in that: When the release mechanism is activated, fluid is released from one or more pre-charged hydraulic chambers (275) connected to the lifting device (230), thereby causing the pressure exerted by the fluid to act on the lifting device (230) for raising or lowering the lifting device.

12. The method according to claim 9, characterized in that: When the release mechanism is activated, one or more compression springs (273) connected to the lifting device (230) are released, thereby causing the mechanical force applied by the one or more compression springs (273) to act on the lifting device (230) for raising or lowering the lifting device.

13. The method according to any one of claims 9 to 12, characterized in that: The release mechanism is activated by dropping the ball onto a ball seat included in the release mechanism.

14. The method according to claim 11, characterized in that: The release mechanism is activated by breaking a disc within a valve (276) in the pre-charged hydraulic chamber (275) included in the release mechanism.

15. The method according to any one of claims 9 to 12, characterized in that: The release mechanism is activated by breaking the shear pin (270) included in the release mechanism.

16. The method according to any one of claims 9 to 12, characterized in that: When a flowable device (281) is detected, the release mechanism is activated by causing the flowable device (281) to trigger an electronic receiving unit, wherein the electronic receiving unit is adapted to control an electric valve included in the core drilling assembly.

Images