Patent Application
20240418076
The disclosure generally relates to the field of wellbore drilling, and more specifically to determining drilling parameters during wellbore drilling.
Drilling equipment, such as drill bits, may include strain gauges that indicate various forces exerted on the drilling equipment. The various forces may introduce biases into certain computations that utilize the strain data (such as determinations of weight). Some drilling systems may perform taring of the stain data to improve accuracy of computations that utilize the strain data. Taring the strain data may involve collecting numerous downhole and surface parameters and performing complex computations. In some instances, the computations may not complete before the parameters change, so drilling systems may have difficulties taring strain data.
Implementations of the disclosure may be better understood by referencing the accompanying drawings.
The description that follows includes example systems, methods, techniques, and program flows that embody implementations of the disclosure. However, this disclosure may be practiced without these specific details. For clarity, some well-known instruction instances, protocols, structures, and techniques may not be shown in detail.
In drilling systems, drill bits and other drill string components may include strain gauges that produce strain data. Drilling systems may use strain data for determining drilling measurements such as weight on bit (WOB), torque on bit (TOB), bending on bit (BOB), and others. However, the strain data may include biases that skew these drilling measurements. For example, when a drill bit is held weightless in a borehole, the drilling system should determine a WOB value of zero. However, despite having no weight on the drill bit, drilling mud and other materials may exert force on the drill bit's strain gauges. These forces may appear in the strain data and affect computations of WOB and other drilling measurements.
Traditionally, drilling systems may cease drilling to determine biases in strain data. While drilling has ceased, the drilling system may hold the drill string weightless in the borehole with no weight on the drill bit. With drilling ceased and no weight on the drill bit, a non-zero WOB value may be associated with bias in the strain data—that is, bias in the strain data may be causing the non-zero value for WOB. Because there is no weight on the drill bit, the drilling system may identify and eliminate the bias in WOB values. However, the process of repeatedly ceasing drilling to determine bias may prolong drilling. Some implementations of this disclosure determine and remove biases from strain data while the drilling bit is drilling the borehole. That is, some implementations may determine and remove bias from strain data without ceasing drilling.
Some implementations continuously determine bias in strain data from strain gauges located in the drill string, such as on tools, tubulars, drill bits, and other drill string components. Some implementations may continuously determine bias in strain data based on one or more of drilling mud weight, true vertical depth of drilling mud, hydrodynamic pressure of the drilling mud, hydrostatic pressure of the drilling mud, and pipe diameter of the drill string, thereby avoiding the traditional process of ceasing drilling and holding the drill string weightless in the borehole. By continuously determining bias in strain data, the drilling system may determine unbiased values for WOB and other drilling measurements at any time during drilling.
Some implementations may determine bias in strain data periodically, on-demand, in response to certain conditions, or in any other suitable manner.
The drilling rig 102 may provide support for the drill string 108. The drill string 108 may operate with the rotary table 110 for drilling the borehole 112 through subsurface formations 114. The drill string 108 may include a Kelly 116, drill pipe 118, and a bottom hole assembly 120 located at the lower portion of the drill pipe 118.
The bottom hole assembly 120 may include one or more drill collars 122, a down hole tool 124, and a drill bit 126. The drill bit 126 may operate to create a borehole 112 by penetrating the surface 104 and subsurface formations 114. The drill bit 126 may include one or more strain gauges 129 that may produce strain data indicting forces exerted on surfaces of the drill bit 126. The forces may be related to forces exerted on the drill bit 126 by hydrostatic pressure of drilling mud in the drill string 108, hydrodynamic pressure of drilling mud flowing through the drill bit 126 and up the annular space between the drill sting and the borehole 112, and more. These forces may appear in the strain data and affect computations of WOB, TOB, and other drilling measurements. In some implementations, the computer system 190 continuously determines bias in the strain data and removes the bias, thereby enabling accurate determination of WOB, TOB, and other drilling measurements. In some implementations, the computer system 190 determines bias in the strain data based on one or more of drilling mud weight, true vertical height of the drilling mud on the drill bit 126, hydrodynamic pressure of the drilling mud, hydrostatic pressure of the drilling mud, and pipe diameter of the drill string 108. By continuously determining bias in strain data, the computer system 190 may continuously determine unbiased values for drilling measurements (such as WOB) at any time during drilling.
During drilling operations, the drill string 108 (perhaps including the Kelly 116, the drill pipe 118, and the bottom hole assembly 120) may be rotated by the rotary table 110. In addition to, or alternatively, the bottom hole assembly 120 may also be rotated by a motor (e.g., a mud motor) that is located down hole. The drill collar 122 may be used to add weight to the drill bit 126. The drill collar 122 may also operate to stiffen the bottom hole assembly 120, allowing the bottom hole assembly 120 to transfer the added weight to the drill bit 126, and in turn, to assist the drill bit 126 in penetrating the surface 104 and subsurface formations 114.
During drilling operations, a mud pump 132 may pump drilling fluid (sometimes known by those of ordinary skill in the art as “drilling mud”) from a mud pit 134 through a hose 136 into the drill pipe 118 and down to the drill bit 126. The drilling fluid can flow out from the drill bit 126 and be returned to the surface 104 through an annular area 140 between the drill pipe 118 and the sides of the borehole 112. The drilling fluid may then be returned to the mud pit 134, where such fluid is filtered. In some implementations, the drilling fluid can be used to cool the drill bit 126, as well as to provide lubrication for the drill bit 126 during drilling operations. Additionally, the drilling fluid may be used to remove subsurface formation 114 cuttings created by operating the drill bit 126. It is the images of these cuttings that many implementations operate to acquire and process.
The strain gauges 129 may measure strain in components on which they are mounted (such as the drill bit 126, drill collar 122, and others). Strain refers to a deformation or change in shape that occurs when the component is subjected to external forces. The strain gauges 129 may include resistive strain gauges that may detect and quantify deformations by measuring changes in the strain gauge's electrical resistance. By measuring changes in resistance, the strain gauges 129 may determine a magnitude and direction of the strain. The strain gauges 129 also may include other suitable types such as capacitive strain gauges or others. Strain may be dimensionless, as it may represent a ratio of change in dimension to the original dimension. Strain data may be expressed as a decimal or a percentage. Some implementations utilize strain to determine pressure, weight, and other drilling measurements (as described herein).
Some implementations may utilize a known relationship between weight and strain. The relationship between weight and strain may be determined under laboratory conditions, through analysis in the field, or through any other suitable methodologies. According to the relationship, an amount of strain may indicate an amount of weight. For example, 1 Micro-strain may indicate 1 lb. of weight on the drill string 108.
Additionally, some implementations may determine a relationship between strain and pressure. Some implementations determine this relationship under laboratory conditions.
In the laboratory environment, the drill bit 126 may include one or more nozzles 212 to restrict drilling mud 204 flowing out of the inner space. Before pumping the drilling mud 204 into the inner space 206 of the drill string 108 (held weightless), the strain gauges 129 may record strain data at 0 pounds per square inch (psi) of hydrodynamic pressure inside the inner space 206. Next, the drilling mud 204 may be pumped into the inner space 206. As the drilling mud 204 is pumped into the inner space 206, hydrodynamic pressure may build up in the inner space 206. The hydrodynamic pressure may apply forces 208 on the inner diameter of the tubulars and components of the drill string 108. The outside of the drill string 108 may be exposed to atmospheric pressure, so there may be very little force pushing inward on the outer diameter of the drill string 108. In some implementations, the drilling mud 204 is pumped into the inner space 206 until a hydrodynamic pressure reaches 2000 psi. At 2000 psi, the strain gauges 129 may record strain data as the hydrodynamic pressure deforms the components of the drill string 108.
As a result of the above-noted operations, the strain data may include strain at 0 psi of hydrodynamic pressure and at 2000 psi of hydrodynamic pressure. As noted, there may be a known relationship between strain and weight. Therefore, when the drill string is held weightless and there is no drilling mud 204 being pumped into the drill string 108 (such as when the hydrodynamic pressure is 0 psi), the strain data indicates a baseline amount of strain for a weightless drill string. For example, at 0 psi, the baseline amount of strain may be 0. When the weightless drill string 108 is exposed to 2000 psi of hydrodynamic pressure, any deviation from the baseline amount of strain for the weightless drill string may be considered bias in the strain data (also referred to as “un-tarred weight”). Hence, these operations indicate a relationship between pressure and un-tarred weight. That is, for each psi of hydrodynamic pressure in the drill string 108, there may be a corresponding number of pounds of un-tarred weight. For example, for each psi of hydrodynamic pressure inside the drill string 108, there may be 6 pounds of un-tarred weight. Hence, for 100 psi of hydrodynamic pressure, there may be 600 pounds of un-tarred weight.
A very similar process is performed to determine a hydrostatic pressure response on WOB computations. For the hydrostatic pressure response, instead of applying force from drilling fluid flow only on the internal bore of the drill string device, force may be applied (pressure in a fluid) all around the entire drill string device. By following a process similar to that noted with reference to
In some implementations, there are no direct pressure measurement devices that directly measure hydrodynamic pressure and hydrostatic pressure. In the absence of direct pressure measurement devices, some implementations use strain data from the strain gauges 129 to determine pressure values in the borehole 112. For example, the computer system 190 may determine hydrodynamic pressure values and hydrostatic pressure values based on strain data from one or more strain gauges 129, vertical depth of drilling mud, mud weight, and other parameters. The computer system 190 may then use the pressure values for determining WOB, TOB, and other drilling measurements.
While the drill string 108 is being used for drilling a well bore, the computer system 190 may use equation 1 to determine hydrodynamic pressure (Pd) on the drill string 108.
Similarly, the computer system 190 may use equation 2 to determine hydrostatic pressure (Ps) on the drill string 108.
In Equations 1 and 2, the parameters are:
The drilling parameters in equations 1 and 2 may vary based on details for each drilling rig. For example, some drilling rigs may utilize a particular size and grade of pipe in their drill strings, while other drilling rigs may utilize different sizes and grades of pipe. As another example, some drilling rigs may utilize drilling mud of a particular weight, while others may utilize drilling mud of other weights. In any case, the computer system 190 is configured to determine values for each of the drilling parameters noted herein. The computer system 190 may determine values for one or more of these drilling parameters of equations 1 and 2 based on sensor information, information in one or more databases, user-provided information, or otherwise accessing one or more data sources indicating values for these parameters.
During drilling, the computer system 190 may use equations 1 and 2 to determine hydrodynamic pressure (Pd) and/or hydrostatic pressure (Pd) about the drill string 108. After the computer system 190 determines the hydrodynamic and/or hydrostatic pressures, the computer system 190 may use relationships between pressure and un-tarred weight to remove bias from the strain data. For example, the computer system 190 may determine hydrodynamic pressure values in the borehole 112 to then determine various drilling measurements such as TOB, WOB, etc. Based on relationships between pressure and un-tarred weight, the computer system may remove bias from strain data and accurately determine drilling measurements such as TOB, WOB, and other drilling measurements.
As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.
The various illustrative logics, logical blocks, modules, circuits, and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described throughout. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.
The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the implementations disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor or any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes and methods may be performed by circuitry that is specific to a given function.
In one or more implementations, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also may be implemented as one or more computer programs, e.g., one or more modules of computer program instructions stored on a computer storage media for execution by, or to control the operation of, a computing device.
If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. The processes of a method or algorithm disclosed herein may be implemented in a processor-executable instructions which may reside on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that may be enabled to transfer a computer program from one place to another. Storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection may be properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-Ray™ disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations also may be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.
Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.
Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the Figures and indicate relative positions corresponding to the orientation of the Figure on a properly oriented page and may not reflect the proper orientation of any device as implemented.
Certain features that are described in this specification in the context of separate implementations also may be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also may be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example process in the form of a flow diagram. However, some operations may be omitted and/or other operations that are not depicted may be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described should not be understood as requiring such separation in all implementations, and the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results.
Some implementations may include the following clauses.
Clause 1: A method for eliminating bias in strain data produced by one or more strain gauges in a drill string, the method comprising: drilling a borehole with the drill string; determining a bias in strain data based on drilling parameters detected during the drilling; and removing the bias from a biased downhole drill string measurement to indicate an unbiased downhole drill string measurement.
Clause 2: The method of clause 1, wherein the drilling parameters include a hydrostatic pressure of drilling mud about the drill string, a weight of the drilling mud, an inner diameter of one or more tubulars in the drill string, and a true vertical depth of the drilling mud in the drill string.
Clause 3: The method of any one or more of clauses 1-2 further comprising: continuously determining additional biases of the strain data based on a hydrostatic pressure of drilling mud in the drill string, a weight of the drilling mud in the drill string, an inner diameter of the drill string, and a true vertical depth of the drilling mud in the borehole.
Clause 4: The method of any one or more of clauses 1-3 further comprising: removing the additional biases from additional biased downhole drill string measurements during the drilling of the borehole.
Clause 5: The method of any one or more of clauses 1-4, wherein the biased downhole drill string measurement indicates a weight on a drill bit of the drill string.
Clause 6: The method of any one or more of clauses 1-5, wherein the biased downhole drill string measurement is torque on a drill bit of the drill string.
Clause 7: The method of any one or more of clauses 1-6 further comprising: causing pressure from drilling fluid to exert force on the drill string; detecting, while holding the drill string weightless, strain from the one or more strain gauges; and determining a relationship between the strain and un-tarred weight on the drill string.
Clause 8: The method of any one or more of clauses 1-7, wherein the pressure is hydrostatic pressure or hydrodynamic pressure.
Clause 9: One or more machine-readable mediums including instructions that, when executed by a processor, eliminate bias in strain data produced by one or more strain gauges in a drill string, the instructions comprising: instructions to determine, while the drill string is drilling a borehole, a bias in strain data based on drilling parameters detected during the drilling; and instruction to remove the bias from a biased downhole drill string measurement to indicate an unbiased downhole drill string measurement.
Clause 10: The one or more machine-readable mediums of clause 9, wherein the drilling parameters include a hydrostatic pressure of drilling mud about the drill string, a weight of the drilling mud, an inner diameter of one or more tubulars in the drill string, and a true vertical depth of the drilling mud in the drill string.
Clause 11: The one or more machine-readable mediums of any one or more of clauses 9-10, the instructions further comprising: instructions to continuously determine additional biases of the strain data based on a hydrostatic pressure of drilling mud in the drill string, a weight of the drilling mud in the drill string, an inner diameter of the drill string, and a true vertical depth of the drilling mud in the borehole.
Clause 12: The one or more machine-readable mediums of any one or more of clauses 9-11, the instructions further comprising: instructions to remove the additional biases from additional biased downhole drill string measurements during the drilling of the borehole.
Clause 13: The one or more machine-readable mediums of any one or more of clauses 9-12, wherein the biased downhole drill string measurement indicates a weight on a drill bit of the drill string.
Clause 14: The one or more machine-readable mediums of any one or more of clauses 8-13, wherein the biased downhole drill string measurement is torque on a drill bit of the drill string.
Clause 15: An apparatus comprising: a processor; one or more machine-readable mediums including instructions that, when executed by the processor, eliminate bias in strain data produced by one or more strain gauges in a drill string, the instructions including instructions to determine, while the drill string is drilling a borehole, a bias in strain data based on drilling parameters detected during the drilling, and instruction to remove the bias from a biased downhole drill string measurement to indicate an unbiased downhole drill string measurement.
Clause 16: The apparatus of clause 15, wherein the drilling parameters include a hydrostatic pressure of drilling mud about the drill string, a weight of the drilling mud, an inner diameter of one or more tubulars in the drill string, and a true vertical depth of the drilling mud in the drill string.
Clause 17: The apparatus of any one or more of clauses 15-16 further comprising: instructions to continuously determine additional biases of the strain data based on a hydrostatic pressure of drilling mud in the drill string, a weight of the drilling mud in the drill string, an inner diameter of the drill string, and a true vertical depth of the drilling mud in the borehole.
Clause 18: The apparatus of any one or more of clauses 15-17 further comprising: instructions to remove the additional biases from additional biased downhole drill string measurements during the drilling of the borehole.
Clause 19: The apparatus of any one or more of clauses 15-18, wherein the biased downhole drill string measurement indicates a weight on a drill bit of the drill string.
Clause 20: The apparatus of any one or more of clauses 15-19, wherein the biased downhole drill string measurement is torque on a drill bit of the drill string.
