System and Method for Downhole Strain Monitoring

This application claims the benefit of U.S. Provisional Patent Application 63/636,904 titled “System And Method For Downhole Strain Monitoring” filed Apr. 22, 2024.

Not applicable.

The disclosed embodiments relate generally to techniques for monitoring strain within a borehole using fiber optic sensing data.

Monitoring strain in the subsurface is critical to calibrating and validating mechanical earth models (MEM). One way to measure the strain is using fiber optic sensing data.

There are some known strain monitoring methods. These previous methods measure strain using direct measurements from fiber optic (FO) sensing data, but as an emerging field, these measurements are often uncertain.

However, there is business need to invent and develop more efficient methods for both calibration of other methods and sole use.

There exists a need for improved methods for measuring and verifying strain measurements in a borehole.

In accordance with some embodiments, a method of monitoring strain in a borehole using fiber optic (FO) sensing data is disclosed. The method may receive fiber optic sensing data recorded in the borehole; identify fingerprint signatures in the fiber optic sensing data caused by known markers; and use the fingerprint signatures to monitor changes in the borehole. In an embodiment, the known markers include downhole jewelry. In another embodiment, the known markers include changes in lithology along the borehole.

In another aspect of the present invention, to address the aforementioned problems, some embodiments provide a non-transitory computer readable storage medium storing one or more programs. The one or more programs comprise instructions, which when executed by a computer system with one or more processors and memory, cause the computer system to perform any of the methods provided herein.

In yet another aspect of the present invention, to address the aforementioned problems, some embodiments provide a computer system. The computer system includes one or more processors, memory, and one or more programs. The one or more programs are stored in memory and configured to be executed by the one or more processors. The one or more programs include an operating system and instructions that when executed by the one or more processors cause the computer system to perform any of the methods provided herein.

Like reference numerals refer to corresponding parts throughout the drawings.

Described below are methods, systems, and computer readable storage media that provide a manner of strain monitoring within a borehole using fiber optic sensing data. The method can measure strain indirectly by tracking the change in position, or displacement, of markers in the well, from which it is possible to estimate strain. The relative spatial distribution of fingerprint signatures associated with downhole jewelry or geologic markers can be used to identify displacement for strain estimation in the wellbore.

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure and the embodiments described herein. However, embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, components, and mechanical apparatus have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

The methods and systems of the present disclosure may be implemented by a system and/or in a system, such as a systemshown in. The systemmay include one or more of a processor, an interface(e.g., bus, wireless interface), an electronic storage, a graphical display, and/or other components. Processorreceives fiber optic sensing data and performs a method to identify strain based on the downhole jewelry fingerprint signatures.

The electronic storagemay be configured to include any electronic storage medium that electronically stores information. The electronic storagemay store software algorithms, information determined by the processor, information received remotely, and/or other information that enables the systemto function properly. For example, the electronic storagemay store information relating to input fiber optic sensing data, and/or other information. For example, the electronic storagemay store information relating to output strain estimates, and/or other information. The electronic storage media of the electronic storagemay be provided integrally (i.e., substantially non-removable) with one or more components of the systemand/or as removable storage that is connectable to one or more components of the systemvia, for example, a port (e.g., a USB port, a Firewire port, etc.) or a drive (e.g., a disk drive, etc.). The electronic storagemay include one or more of optically readable storage media (e.g., optical disks, etc.), magnetically readable storage media (e.g., magnetic tape, magnetic hard drive, floppy drive, etc.), electrical charge-based storage media (e.g., EPROM, EEPROM, RAM, etc.), solid-state storage media (e.g., flash drive, etc.), and/or other electronically readable storage media. The electronic storagemay include one or more non-transitory computer readable storage medium storing one or more programs. The electronic storagemay be a separate component within the system, or the electronic storagemay be provided integrally with one or more other components of the system(e.g., the processor). Although the electronic storageis shown inas a single entity, this is for illustrative purposes only. In some implementations, the electronic storagemay comprise a plurality of storage units. These storage units may be physically located within the same device, or the electronic storagemay represent storage functionality of a plurality of devices operating in coordination.

The graphical displaymay refer to an electronic device that provides visual presentation of information. The graphical displaymay include a color display and/or a non-color display. The graphical displaymay be configured to visually present information. The graphical displaymay present information using/within one or more graphical user interfaces. For example, the graphical displaymay present information relating to fiber optic sensing data, jewelry fingerprint signatures, strain estimates, and/or other information.

The processormay be configured to provide information processing capabilities in the system. As such, the processormay comprise one or more of a digital processor, an analog processor, a digital circuit designed to process information, a central processing unit, a graphics processing unit, a microcontroller, an analog circuit designed to process information, a state machine, and/or other mechanisms for electronically processing information. The processormay be configured to execute one or more machine-readable instructionsto facilitate strain monitoring. The machine-readable instructionsmay include one or more computer program components. The machine-readable instructionsmay include a fiber optic (FO) sensing data component, a stacking component, a domain transform component, and a slope component, and/or other computer program components. By way of example but not limitation, additional components may include signal processing components. Signal processing flows could include, but are not limited to, correlation of subsequent traces with a baseline trace to track the change in correlation coefficient, deconvolution of subsequent traces with a baseline trace to track the change in deconvolution, computer vision/artificial intelligence/machine-learning methods, other frequency analysis methods, and/or other signal processing that will aid in tracking our special fingerprint signatures.

It should be appreciated that although computer program components are illustrated inas being co-located within a single processing unit, one or more of computer program components may be located remotely from the other computer program components. While computer program components are described as performing or being configured to perform operations, computer program components may comprise instructions which may program processorand/or systemto perform the operation.

While computer program components are described herein as being implemented via processorthrough machine-readable instructions, this is merely for ease of reference and is not meant to be limiting. In some implementations, one or more functions of computer program components described herein may be implemented via hardware (e.g., dedicated chip, field-programmable gate array) rather than software. One or more functions of computer program components described herein may be software-implemented, hardware-implemented, or software and hardware-implemented.

Referring again to machine-readable instructions, the FO sensing data componentmay be configured to receive fiber optic sensing data that has been acquired for extended periods of time (hours, days, weeks, months, or years) from within the borehole. FO sensing data may include distributed acoustic sensing (DAS), distributed strain sensing (DSS), distributed temperature sensing (DTS) data, and/or other types of data acquired by fiber optic sensing. By way of example and not limitation,shows two possible configurations of how the fiber optic cable is deployed; these are not meant to be limiting. As those of skill in the art are aware, a borehole may contain a well casingwhich may, in turn, have production tubinginside it. The fiber optic cablemay be affixed to the well casing(configuration in left drawing) or the production tubing(configuration in right drawing). The fiber optic cablemay be affixed to the well casingor the production tubingwith downhole jewelry. Downhole jewelrymay include cross coupling clamps (see), centralizers (see), and the like.also shows example fingerprint signatures. Fingerprint signatures are likely due to thermal or mechanical strain. The position change can be tracked over time, indicating strain along the FO cable. The fingerprint signatures may be associated with any known object position in the well, including permanent and nonpermanent, i.e., retrievable, markers. The markers may be downhole jewelry, lithology changes, and the like.

The stacking componentmay be configured to stack the traces of the FO sensing data along the time axis for a user-specified time frame within a user-selected depth interval. Stacking improves the signal-to-noise ratio of the fingerprint signatures. Note that the stacking is a type of signal processing; other signal processing may be used in place of or in addition to the stacking.shows an example of stacking the traces along the time axis.

The domain transform componentmay be configured to transform the FO sensing data into the wavenumber domain. In an embodiment, the transformation into the wavenumber domain may be done rather than the stacking, then the transformed traces may be averaged. The lower panel ofshows the fingerprint signatures in the wavenumber domain.

The slope componentmay be configured to identify the changes of the peaks over time. By separating the extended-period recording into smaller time windows, such as week-long or shorter, individual peaks in the wavenumber domain can be found for each smaller time window. In an embodiment, linear regression can then be used to fit peaks of local maxima and the slope is determined. The sign of slope determines whether analyzed depth section is extending/dilating (negative strain), compressing/compacting (positive strain), or neither.show examples.shows two years of time lapse analysis broken into month long increments; early times in dark greys, later times in lighter greys.shows that to quantify how strain changes with time, the method will repeat regression fit over time. The slope gradient enables an estimate of strain gradient. In, a slope of ˜17 microstrain per year indicates overburden is compacting (positive strain) at a quantifiable rate. An increasing wavenumber of time equates to a decreasing wavelength over time, which indicates compression. A decreasing wavenumber of time equates to an increasing wavelength over time, which indicates extension.

The description of the functionality provided by the different computer program components described herein is for illustrative purposes, and is not intended to be limiting, as any of computer program components may provide more or less functionality than is described. For example, one or more of computer program components may be eliminated, and some or all of its functionality may be provided by other computer program components. As another example, processormay be configured to execute one or more additional computer program components that may perform some or all of the functionality attributed to one or more of computer program components described herein.

While particular embodiments are described above, it will be understood it is not intended to limit the invention to these particular embodiments. On the contrary, the invention includes alternatives, modifications and equivalents that are within the spirit and scope of the appended claims. Numerous specific details are set forth in order to provide a thorough understanding of the subject matter presented herein. But it will be apparent to one of ordinary skill in the art that the subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.

As used herein, the term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in accordance with a determination” or “in response to detecting,” that a stated condition precedent is true, depending on the context. Similarly, the phrase “if it is determined [that a stated condition precedent is true]” or “if [a stated condition precedent is true]” or “when [a stated condition precedent is true]” may be construed to mean “upon determining” or “in response to determining” or “in accordance with a determination” or “upon detecting” or “in response to detecting” that the stated condition precedent is true, depending on the context.

Although some of the various drawings illustrate a number of logical stages in a particular order, stages that are not order dependent may be reordered and other stages may be combined or broken out. While some reordering or other groupings are specifically mentioned, others will be obvious to those of ordinary skill in the art and so do not present an exhaustive list of alternatives. Moreover, it should be recognized that the stages could be implemented in hardware, firmware, software or any combination thereof.

The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.