METHOD OF WELL DECOMMISSIONING IN THROUGH-TUBING APPLICATIONS

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to provisional application No. 63/387,823, titled “Method of Well Decommissioning in Through-Tubing Applications,” filed on Dec. 16, 2022, the contents of which are incorporated in their entirety.

BACKGROUND

Downhole mechanical service tools allow for performing operations within a wellbore. Producing hydrocarbons from a wellbore drilled into a geological formation is a remarkably complex endeavor. In many situations, a casing may be disposed within the wellbore to assist in transporting hydrocarbons from within the geological formation to a collection facility at the surface of the wellbore. In other situations, the casing may be used to isolate and/or protect delicate systems within the casing from physical damage (e.g., abrasion, exposure to corrosive well bore fluids) due to contact with the geological formation.

When it is time to decommission the well, casing and tubular elements might remain present in the wellbore. It may be difficult or even impossible to remove the casing and tubular elements as part of the decommissioning. To decommission the well, a series of barriers must be established to prevent the uncontrolled flow of fluid through the various annular spaces that may be present in the wellbore. To accomplish this goal, a rock-to-rock barrier must be established.

Additionally, during the active life of a well, slot recovery and integrity restoration processes may need to be performed. Systems are needed that allow for real-time assessment to make adjustments to the well as needed.

New systems and methods are needed to complete that goal without requiring the removal of tubulars.

SUMMARY

The examples described herein allow for the safe decommissioning of a well without requiring removal of all tubular elements present in a wellbore. The systems and methods allow for performing that operation through a series of steps, which can be fully evaluated in real time and repeated at will. The evaluation can be performed without the need for a trip back to surface to reset or redress the bottomhole assembly. These systems and methods can provide a significant value by reducing the overall operational complexity, scope, and time. Simplification provides both commercial advantages and safety for operators in the space.

Many regulators today would not accept a barrier that considers a control line penetrating within the barrier for well decommissioning purposes. As a result, a novel solution is required to mitigate this by doing series of operations to establish that the flow through the control line has been eliminated by a series of potential options: (1) filling of the control line, (2) segmenting the control line into smaller, discontinuous sections, and (3) confirmation of positioning and isolation of control lines following a segmenting operation.

A downhole tool can perform the segmenting, perforating, cleaning, and cementing. A control device, which can include a processor, can carry out stages of analysis to determine how to reconfigure the well for decommission. The processor can execute instructions on a physical non-transitory, computer-readable medium, in an example.

The method can include analyzing tubing integrity, casing, and eccentricity to build in a hydraulic model. The hydraulic model can optimize the perforating and wash regime implemented in other steps. Building the hydraulic model can include configuring a window cut through the tubings. It can also include configuring a washing operation and compounds to be utilized.

The hydraulic model can be a mathematical representation or simulation of the fluid flow dynamics within the wellbore and the surrounding reservoir. This model can be used to analyze and predict the behavior of fluids, such as drilling mud, completion fluids, or production fluids, as they move through the wellbore and interact with the reservoir rock.

The hydraulic model can predict and analyze the effects of various parameters on wellbore and reservoir performance. This can include predicting pressures, flow rates, temperature changes, and the potential for issues such as wellbore instability or formation damage. The real-time data can be compared against the model during various operations. This allows for dynamic adjustments and immediate responses to changing conditions.

The model can consider the principles of fluid dynamics to simulate the movement of fluids through the wellbore, including flow rates, pressures, and velocities. It can also take into account the physical characteristics of the wellbore, such as the size and geometry of the casing and tubing, wellbore trajectory, and the presence of any completion or production equipment. Information about the reservoir rock, including its permeability, porosity, and other reservoir properties, is incorporated into the model. This helps simulate the interaction between the fluid and the reservoir.

The method can also include reconfiguring the completion or tubulars, such as for regaining access and eliminating the control line. If perforating, the system can drop guns prior to other steps to reduce bottomhole assembly (“BHA”) length.

Depending on the well configuration, the operation can include passive or active orientation to optimize the efficiency of the cutting operations. During the cutting operations, the system can measure the well state.

The system can also confirm that the state of the well can be validated after reconfiguration. The validation can include using a camera, ultrasonic sensor, or other measurement to confirm that the well is in the required state for proceeding in the same or subsequent descent.

The system can further perform a washing operation to remove residual cement that is present in a variety of annuli. This step can be completed with the direct measurements downhole to monitor the progress of the operation in real-time. The reconfiguration can be confirmed and validated after this step in an example. The confirmation and validation can alternatively come after a cementing operation in which cement is pumped into the annual space, in an example.

It is understood that the aforementioned workflow can happen sequentially. However, the introduction of measurements and evaluation throughout the proposed invention can enable further control opportunities. For example, the system can control parts of or the entire bottomhole assembly. The additional control can allow the system to optimize the utilization of the bottomhole assembly to improve efficiency and effectiveness of the operation. The method also paves the way to new execution workflows that may not necessarily be sequential. For instance, one may decide to repeat one or a combination of steps based on the results of an evaluation during the operation. In such a case, the bottomhole assembly can selectively actuate parts in order to enable or disable at will the different applications contained in this invention, such as perforating, cutting, high-pressure jetting, cementing, and logging. Consequently, the aforementioned system may contain selective actuation sub, fully compatible with the telemetry and power delivery systems.

In some examples, if the state of the well may allow for completing the decommissioning operations with fewer steps. For example, the scope of work may be adjusted for wells that are pre-configured already, eliminate steps such as bullheading cement, bridge plug placement, or wells killed.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the embodiments, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate various embodiments and aspects of the present invention. In the drawings:

FIG. 1 is an example flow chart of a method for well decommissioning.

FIG. 2 is an example system diagram of components and sections of a wellbore that can be involved in and impacted by the method.

DESCRIPTION OF THE EXAMPLES

Reference will now be made in detail to the present exemplary examples, including examples illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The described examples are non-limiting.

Although examples discuss decommissioning operations, the method can also be used for maintenance and other operations in a well. In general, the method can be used to identify a location for a barrier in a well, placing the barrier, and verifying the integrity of the barrier. The method can allow for adjusting based on real-time conditions within the well. Examples presented for decommissioning should not be construed as limited to that particular operation unless specified otherwise.

An example method can perform a series of operations to establish that the flow through the control line has been eliminated by a series of potential options: (1) filling of the control line, (2) segmenting the control line into smaller sections, and (3) confirmation of positioning of control lines following a segmenting operation.

FIG. 1 is an example flow chart of stages performed by a system for well decommissioning or other downhole operations. At stage 105, the system can use a drift to confirm well depth. The drift can be a cylindrical tool that is run downhole to assess the internal diameter of the well casing or tubing. The system can ensure that the casing or tubing has not been deformed during installation and that there is enough clearance for subsequent tools or equipment to pass through smoothly.

Stage 105 can optionally include confirming the control line positioning and cements in the annular space of the well. The positioning can allow an operator to confirm the type of sensor to use for the operations, confirm any annular space that requires remediation, and determine how to perforate. The drift tool can be designed or selected to match the specified diameter of the casing or tubing. If the drift passes through the wellbore without any issues, it confirms that the internal diameter is within acceptable limits. If the drift encounters resistance or does not pass through a particular section, it indicates a potential problem, such as a deformation or obstruction in the casing.

Although cement is used as an example material for casing, other materials can also be used with the methods disclosed herein.

An initial confirmation of the of the annual contents and their properties present in the space. This can be done using ultrasonic and nuclear measurements. A multi-model measurement using sonic, ultrasonic, and nuclear measurements can allow the user or system to determine how to best proceed in perforating.

At stage 110, the system can perform analytics of tubing integrity. This can include analyzing the casing and eccentricity to build a hydraulic model. The hydraulic model can optimize the perforating and wash regime implemented in future stages. Stage 110 can include configuring a window cut through the tubings. Stage 110 can also include configuring a washing operation and compounds to be utilized.

The terms perforate and cut are used interchangeably. But in general, either can provide hydraulic communication access through the tubings. Overall, the system needs to create access for the future stages.

At stage 115, the system can set a fundament. The fundament can be a plug or other device. Stage 115 may not be necessary if non-cement-based barriers are used.

At stage 120, the system can reconfigure the completion or tubulars. This can include regaining access or eliminating the control line. At stage 120, the system may require multiple operations to achieve the required annular access at a given depth. If the system is perforating the tubings, different gun sizes may be required. Likewise, multiple different gun types may be used in order to cut through the various media in the wellbore. The system can optionally drop guns at different stages to reduce bottom hole assembly (“BHA”) length. The BHA can include a combination of drill bits, drill collars, mud motor, measurement tools, logging tools, directional drilling tools, and stabilizers.

Depending on the well configuration, the operation can require passive or active orientation to optimize the efficiency of creating the annular access. Again, creating the annular access can include any type of cutting or perforating operations.

During the operation, the system can measure the well state in real time. These real time measurements can inform the orientation of tools creating the access. Additionally, this can allow the user or system to recognize the need to reconfigure the tool-string configuration or operating mode. Some operations can require different tools and operation modes to achieve the annular access.

At stage 125, the system can confirm the reconfiguration of the well. This can include using a camera, ultrasonic sensor, or other measurement method. The system can confirm that the well is in the required state to proceed forth.

To confirm the annular contents and their properties in the space as part of the model, the system can use a combination of ultrasonic and nuclear measurements. These can be individual measurements or a multi-model measurement that takes advantage of camera, sonic, ultrasonic, and nuclear measurements. A processor can incorporate the measurements in modeling the space and the annular contents.

This can confirm that the target state of the well has been reached. The target state can also be verified based on measurements of density and composition of liquid or material in the space.

At stage 130, the system can perform a washing operation to remove residual cement (or other material) that is present in a variety of annuli. Stage 130 can be completed as part of a direct measurement downhole to monitor in real time the progress of the operation.

Plug and Abandonment (“P&A”) operations can include a washing operation that can be optimized with real-time measurements of pressure and temperature.

The washing operation can be performed with real-time downhole pressure and temperature measurements (coupled with surface indications). This can allow for adjusting rates of washing and other operating parameters, such as fluid type, while removing residual cement or annular debris that can be present in annuli in the wellbore. The system can automatically adjust operation in some circumstances. The user can also read the data on a graphical user interface (“GUI”) and make control and operating parameter adjustments as needed.

At stage 135, the system can again confirm that the current well configuration can be validated in its target state. Again, the system can use a camera, ultrasonic sensors, or other form of measurement. The system can confirm that the well is in the required state to proceed.

At stage 140, the system can perform operation to ensure the completion is configured adequately. For example, the system can ensure that the barriers are optimally conditioned for placement. This can include verifying that the barriers or well walls are free of contamination. For cement barriers, the system can confirm that all surfaces are wet for bonding and appropriate spacers are installed.

At stage 145, a barrier placement operation can be performed. Cementing is one type of barrier placement, but other materials can also be used. The system can place a barrier with the required length at a target location in accordance with design requirements.

The system can set a sleeve or barrier to enable the isolation of cement pumping. The pumping can be isolated such that cement is pumped into the annular spaces first, in an example.

The system can then pump the cement into the annular space in an example, such as in between the different well components or different casing strings of the wellbore. The system can then make measurements to confirm the cement quality. Then the system can pump cement directly into the tubular.

The system can also mill the cement to confirm the quality of the cement.

In the context of well decommissioning, placing barriers in the annular space between casing strings is a critical step to ensure the integrity and isolation of different zones within the well. The barriers can be composed of materials like cement or specialized sealing materials that solidify and create a permanent seal. This process helps prevent the movement of fluids between different geological formations and enhances the overall environmental and safety integrity of the wellbore.

At stage 150, the system can validate the reconfiguration of the well. This can confirm that the well is in the required state for the method to continue. Again, a camera, ultrasonic sensor, or other measurement device can be used.

Additionally, a pressure gauge or other sensor package can be placed below the barriers that have been put in place. The pressure gauge can confirm with a pressure cycle that the barrier has integrity. The system can also perform a volumetric estimation of the cement placed and the top of the cement identified.

The method of FIG. 1 can be performed sequentially. The method can allow for further control opportunities of the bottomhole assembly to improve efficiency and effectiveness of the operation. The method can also be performed as a nonsequential workflow. For example, an operator may decide to repeat one or a combination of steps based on the results of an evaluation made during performance of the method. To allow for this nonsequential workflow, the bottomhole assembly can be capable of selective actuation, such that functions of the bottomhole assembly can be enabled or disabled at will. These functions include perforating, cutting, high-pressure jetting, cementing, and logging. Therefore, the system can contain selective actuation controls that are compatible with telemetry and power delivery systems.

The method of FIG. 1 can also be used for effectively establishing barriers in annular spaces without P&A as the target state. For example, the method of FIG. 1 can be used for slot recovery and barrier restoration. Slot recovery can include the same wellbore evaluation stages and slot cleaning, such as clearing and cleaning the well slot to remove debris and obstructions. Slot recovery can also require re-entry and re-drilling, such as re-drilling to a desired depth or target formation. It can also include installing new casing and cementing to ensure wellbore integrity and prevent fluid migration. Slot recovery is often performed to maximize the utilization of existing infrastructure and reduce the environmental impact associated with drilling additional wells.

FIG. 2 is an example system diagram of components and sections of a wellbore that can be involved in and impacted by the method. The wellbore is shown in sections that can correspond to different stages and operations of the method.

The system can include a head assembly. The head assembly corresponds to the upper part of the wellhead equipment. The wellhead is the structure at the surface of the well that provides support for the casing strings and various tools used in drilling, completion, and production operations.

A locating assembly controlled from the surface can include a casing collar locator (“CCL”) or another locating technology, such as gamma ray (“GR”) correlation. A CCL can determine the depth and location of casing collars within a wellbore. Casing collars are typically thicker and more rigid portions of the well casing, and they are often installed at regular intervals along the length of the well. The CCL can be used during logging or other downhole operations to identify these casing collars and measure the depth at which they are located.

In one example, the CCL works by detecting changes in the electromagnetic field as it passes over the casing collar. The electromagnetic response from the collar is recorded, and this information is used to identify the collar's depth and the interval between collars.

Knowing the precise depth and location of casing collars can be important for various well operations, including logging, wellbore evaluation, and the placement of downhole tools. It helps in accurately correlating well data, understanding the wellbore structure, and making informed decisions during drilling and production activities.

Locating using GR correlation can be helpful in wells where non-magnetic alloys are used. Non-magnetic alloys do not generate a CCL signature. GR correlation can include using natural gamma ray measurements to reference against GR signatures of various lithologies. This can allow the system to confirm BHA positioning with respect to the native rock in the well.

Alternative methods can include an ultrasonic device that looks for diameter changes in the completion. The system can also utilize a caliper device to check diameter changes in the completion.

The system can also include an auxiliary measurement sub-assembly (“sub”). For example, other measurements such as temperature and pressure can be taken by the measurement sub-assembly. These can be correlated to the depth in the well based on the CCL and depth telemetry.

An imaging sub-assembly can include sensors, lights, and cameras for collecting visual information.

The system can also include a flow sub-assembly with bypass and flow control. This can be a downhole tool or assembly that is designed to control and manage the flow of fluids in and out of sections of the wellbore. The use of a flow sub-assembly with bypass and flow control can allow operators to have greater control over downhole conditions, optimize production, and respond to various challenges that may arise during the life cycle of a well.

The flow sub-assembly can include valves, ports, and other features to control and direct the movement of fluids. The bypass can include a secondary pathway or channel for fluid flow. This can be useful for redirecting or diverting fluids to achieve specific objectives, such as avoiding obstructions or controlling the rate of flow. This allows the system to regulate the rate and direction of fluid flow. In the context of a wellbore, flow control mechanisms can be crucial for managing reservoir fluids, controlling pressure, and optimizing production or intervention operations.

A jetting sub-assembly can be used for the cleaning and perforation stages. The tool can use high-pressure fluid jets to accomplish these tasks. A jetting sub-assembly can include a tool string with the jetting tool. The tool string is lowered into the wellbore on a wireline, slickline, coiled tubing, or drill string, depending on the application.

As the high-pressure fluid exits the nozzles, it creates powerful jets. These jets are directed at the wellbore wall, perforating targets, or specific formations. The force of the jets allows the tool to perform various tasks, such as cleaning debris and perforating casing or formations.

A key feature of the jetting sub-assembly is the presence of nozzles or jets (also called guns). These are openings through which high-pressure fluid is expelled. The number, size, and orientation of the nozzles can vary based on the intended purpose of the tool. They can also be deployed in different configurations based on real-time data. During the operation, the well operator can monitor the pressure, flow rate, and other parameters described above to ensure the effective performance of the jetting sub-assembly. Processor-driven control systems may be used to adjust the tool's operation in real-time.

A control line removal and destruction sub-assembly can remove or retrieve control lines or cables that have been previously installed in the well. Control lines are used in wells to convey signals, power, or data between the surface and downhole instruments, such as valves, sensors, or other monitoring and control devices. The control line removal sub-assembly facilitates the extraction of these lines, typically for well intervention or abandonment purposes. The control line removal sub-assembly can be part of a tool string. The control line removal sub-assembly can include a gripper or cutting mechanism to hold the control line. The tool can then apply force to either cut the control line or grip it securely.

A plug sub-assembly includes a set of tools or components designed to place plugs within the wellbore. Plugs are used to isolate specific zones, control fluid flow, or perform other well intervention operations. The assembly can include a disconnect to disassemble part of the assembly, which can remain with the plug in an example. Cement or casing fundament can be used for structural integrity or for zonal isolation.

An annular access sub-assembly can provide access to the annular space between the casing and tubing in the wellbore in an example. It can include instrumentation for installing sensors and tools within the annular space. The tool can also include mechanisms for sealing off sections of the annular space, allowing for controlled operations.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is understood that the control functionality can be carried out be a processor-enabled device, which can be separate from or part of the slot cutter, depending on the example. Also, the terms slot cutter and cutting device are used interchangeably. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.