Patent ID: 12241366

DETAILED DESCRIPTION

Certain aspects and examples of the present disclosure relate to determining operating parameters for a wellbore operation while taking resonance into account. A mechanical system can be under mechanical resonance, or at a resonance speed, when a frequency of operation of equipment, such as drilling machinery, equals a natural frequency of the system. The system undergoing resonance can be displaced by large operational amplitudes, which often results in large mechanical stresses in a body of the mechanical system. Thus, avoiding resonance may be beneficial when dynamic machinery is being operated, such as during a drilling operation when a drill pipe and a drill bit of drill machinery are subjected to mechanical stresses. During the drilling process, the drill string is affected largely by two types of vibrations, the lateral vibration of the string, and the torsional vibration of the string. Thus, the drill machinery has the possibility of undergoing lateral forward whirl vibration. If the mechanical stresses on the drill machinery are sufficiently large, it may cause dramatic failures, which might lead to economic losses and an indefinite delay in completion of the drilling process.

By using a system according to some examples, resonance can be taken into account prior to a drilling operation, which can reduce a likelihood of operating at a resonance condition. Avoiding operating at a resonance condition may result in less wear and tear on the system from the high stresses and displacements imposed on the system. Additionally, using the system to avoid operating at a resonance condition can lead to lower operation costs caused when a drilling system malfunctions from going into resonance.

Weight-on-bit (WOB) and rotations-per-minute (RPM) are examples of drilling parameters that can affect whether the drilling system is subjected to resonance or not. The RPM values at each WOB for which stress and displacement values peak can be considered to be critical speeds. Critical speeds are also called resonance speeds, where the stress and displacement in a mechanical system becomes significantly large compared to the values of stress and displacement in the vicinity of the noted critical speeds.

In some examples, a plot can be generated that illustrates operating conditions in which the resonance speeds occur during the drilling operation. For a particular WOB and RPM of the drilling operation, a particular RPM-WOB point can be shown on the plot. A set of points can be identified as lying in a particular region in the plot, and operating in the particular region can render the drilling system devoid of vibration. The region can be chosen as a suitable region of operation based on wellbore parameters and other characteristics of the drilling operation. Constraints may be added in the form of curves to the WOB-RPM plot, which can reduce a span of the suitable region of operation. The constraints may pertain to a maximum mechanical specific energy (MSE), a maximum hydro-mechanical specific energy (HMSE), a bit-wear rate of penetration (ROP) line, etc.

An additional set of curves can be added to the plot that indicates the values of RPM-WOB points that are to be avoided to prevent resonance from inducing in the system. A plot can generated for each depth of the drilling operation. Less prominent resonance points, which can be an RPM-WOB pair that causes resonance but is not prominent, may be removed from the chart to improve readability of the chart. The less prominent resonance points can correspond to points that display low levels of induced stress and displacement compared to the stress and displacement at other resonance points. The plot can be a guideline during the drilling operation that can allow an operator to identify values of the operating parameters that can cause the system to be at a resonance speed. As a result, operating parameters can be selected that avoid the resonance speeds. The system may be able to automatically implement the selected operating parameters determined from the plot by sending the selected operating parameters as setpoints for the parameters to the drilling system.

Illustrative examples are given to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects, but, like the illustrative aspects, should not be used to limit the present disclosure.

FIG.1is a schematic diagram of a drilling rig100for drilling a wellbore102into a subterranean formation101according to one example of the present disclosure. In this example, drilling rig100is depicted for a well, such as an oil or gas well, for extracting fluids from a subterranean formation101. The drilling rig100may be used to create a wellbore102from a surface110of the subterranean formation101. The drilling rig100includes a well tool or downhole tool118, and a drill bit120. The downhole tool118can be any tool used to gather information about the wellbore102. For example, the downhole tool118can be a tool delivered downhole by wireline, often referred to as wireline formation testing (“WFT”). Alternatively, the downhole tool118can be a tool for either measuring-while-drilling or logging-while-drilling. The downhole tool118can include a sensor component122for determining information about the wellbore102. Examples of information can include ROP, WOB, standpipe pressure, depth, mud flow in, RPM, torque, equivalent circulation density, or other parameters. The downhole tool118can also include a transmitter124for transmitting data from the sensor component122to the surface110. The downhole tool118can further include the drill bit120for drilling the wellbore102.

The wellbore102is shown as being drilled from the surface110and through the subterranean formation101. As the wellbore102is drilled, drilling fluid can be pumped through the drill bit120and into the wellbore102to enhance drilling operations. As the drilling fluid enters into the wellbore, the drilling fluid circulates back toward the surface110through a wellbore annulus128—the area between the drill bit120and the wellbore102. Fractures104,106, or108may be of natural origin or may be created during drilling operations. For example, fractures in the wellbore may be induced by increasing the pressure of the drilling fluid until the surrounding formation fails in tension and a fracture is induced.

Also included in the schematic diagram is a computing device126. The computing device126can be communicatively coupled to the downhole tool118and receive real-time data about the drilling process. The computing device126can use the real-time data to determine and implement drilling parameters for the drilling operation. The computing device126can select drilling parameters that avoid resonance speeds for the drilling equipment.

FIG.2is a block diagram of a computing device200for determining parameters for a wellbore operation based on resonance speeds of drilling equipment according to one example of the present disclosure. WhileFIG.2depicts the computing device200as including certain components, other examples may involve more, fewer, or different components than are shown inFIG.2. In an example, the computing device200may be implemented as the computing device126, as described above with respect toFIG.1.

As shown, the computing device200includes a processor202communicatively coupled to a memory204by a bus206. The processor202can include one processor or multiple processors. Non-limiting examples of the processor202include a Field-Programmable Gate Array (FPGA), an application-specific integrated circuit (ASIC), a microprocessor, or any combination of these. The processor202can execute instructions208stored in the memory204to perform operations. In some examples, the instructions208can include processor-specific instructions generated by a compiler or an interpreter from code written in any suitable computer-programming language, such as C, C++, C#, or Java.

The memory204can include one memory device or multiple memory devices. The memory204can be non-volatile and may include any type of memory device that retains stored information when powered off. Non-limiting examples of the memory204include electrically erasable and programmable read-only memory (EEPROM), flash memory, or any other type of non-volatile memory. At least some of the memory device includes a non-transitory computer-readable medium from which the processor202can read instructions208. A non-transitory computer-readable medium can include electronic, optical, magnetic, or other storage devices capable of providing the processor202with the instructions208or other program code. Non-limiting examples of a non-transitory computer-readable medium include magnetic disk(s), memory chip(s), ROM, random-access memory (RAM), an ASIC, a configured processor, optical storage, or any other medium from which a computer processor can read the instructions208.

The computing device200may receive real-time data210for a drilling operation. The drilling operation can be occurring concurrently with the computing device200receiving the real-time data210. Sensor components deployed downhole in a wellbore can send the real-time data210to the computing device200. The real-time data210can include wellbore parameters and drilling information. For example, the real-time data210can include a wellbore inclination, drilling depth, standpipe pressure, mud flow in, rate of penetration, torque, equivalent circulation density, or any other drilling data. For the drilling depth and a WOB value, the computing device200can determine an RPM value212that corresponds to a resonance speed. That is, the computing device200can determine the RPM value212that can cause drilling equipment to experience vibration when used in correlation with the WOB value. The WOB value and the RPM value212that corresponds to a resonance speed can be considered a resonance speed point. The computing device200can determine an RPM value212for each possible WOB value of the drilling equipment. Additionally, each WOB value may be associated with multiple RPM values212that correspond to resonance speeds. It may be beneficial to avoid the RPM values212that correspond to the resonance speeds to avoid lateral forward whirl.

The computing device200can generate a plot214of the resonance speed points. One or more curves can be generated on the plot214by connecting the resonance speed points. The computing device200can also determine a stable region in the plot214, such as by performing dynamic-stability analysis. The stable region can correspond to combinations of WOB values and RPM values that may help mitigate vibration that might occur during the drilling operation as a result of dynamic instability. The stable region can be bounded by curves corresponding to torsional instability and lateral instability. Bounding the stable region can ensure that RPM values and WOB values that result in backward whirl or torsional stick-slip vibration are avoided during the drilling operation. The curves for the resonance speed points may be within the stable region, but can be considered unstable points. The computing device200can also add constraints to the plot214, which can reduce a size of the stable region. The constraints can include one or more of a maximum mechanical specific energy curve, a maximum hydro-mechanical specific energy curve, a bit-wear rotations-per-minute curve, or a combination thereof.

The computing device200may determine that a WOB value is associated with multiple RPM values212that correspond to resonance speeds. The computing device200can compare stresses and displacements associated with each of the resonance speeds to determine which resonance speed point for the WOB value is associated with a higher stress and displacement. To improve cleanliness and readability of the plot214, the computing device200can remove resonance speed points that are associated with lower stresses and displacements.

The computing device200may additionally determine and remove outliers from the plot214. To identify an outlier, the computing device200may use a suitable algorithm, such as a z-scoring model, a proximity-based model, a linear regression model, or a statistical model. The computing device200can then remove resonance speed points determined to be outliers.

In some examples, the computing device200includes a display device222. The display device222can represent one or more components used to output data. Examples of the display device222can include a liquid-crystal display (LCD), a computer monitor, a touch-screen display, etc. The computing device200can output the plot214to a user interface of the display device222. An operator may then use the plot214to determine drilling parameters216for the drilling operation.

The computing device200can determine drilling parameters216that are to be used for the drilling operation. The drilling parameters216can be selected for the drilling depth indicated in the real-time data210. The drilling parameters216can include an operating WOB value and an operating RPM value. The computing device200can select a combination of a WOB value and an RPM value that is within the stable region and that is not a resonance speed point on the plot214.

The computing device200can also include an action module218. The action module218can include executable program code for taking one or more actions based on the plot214. For example, computing device200may execute the action module218to adjust the drilling operation to use the drilling parameters216, which can avoid operating at conditions associated with a resonance speed, therefore reducing operating costs resulting from a drilling system malfunctioning from going into resonance. The action module218can send the drilling parameters216to the drilling system, which can use the drilling parameters216as control setpoints during the drilling operation.

FIG.3is a graph300of an example of an RPM value that corresponds to a resonance speed306according to one example of the present disclosure. The graph300corresponds to a particular WOB value. An x-axis302of the graph300corresponds to RPMs, and a y-axis304of the graph300corresponds to stress. The resonance speed306is the RPM value at which the stress becomes significantly large, or peaks, for the WOB value. As illustrated inFIG.3, the resonance speed306is one-hundred forty-eight RPMs for the particular WOB value. Thus, drilling equipment should not be operated at the particular WOB value and one-hundred forty-eight RPMs to avoid operating at the resonance speed306.

FIG.4is a graph400of an example of a plot of WOB values and associated RPM values that correspond to resonance speeds according to one example of the present disclosure. The graph400corresponds to a particular drilling depth. An x-axis402of the graph400corresponds to RPMs, and a y-axis404of the graph400corresponds to WOB in pounds. Points of (RPM, WOB) on the graph400correspond to resonance speed points, or combinations of WOB values and RPM values that result in a resonance speed. The resonance speed points can be determined for a range of WOB values. As illustrated, RPM values that result in resonance speeds are determined for WOB values between zero and one-hundred thousand pounds. The resonance speed points can be connected to form curves406of values that are to be avoided during a drilling operation. For examples, the curves406indicate combinations of WOB values and RPM values that may result in forward whirl for the drilling equipment, so any points on the curves406should be avoided to improve a drilling operation.

FIG.5is a graph500of another example of a plot of WOB values and associated RPM values that correspond to resonance speeds according to one example of the present disclosure. The graph500corresponds to a particular drilling depth. An x-axis502of the graph500corresponds to RPMs, and a y-axis504of the graph500corresponds to WOBs in pounds. The graph500includes a stable region510determined based on dynamic-stability analysis. The stable region510corresponds to WOB values and RPM values for which a drilling operation can be stable. The stable region can be bounded by curves corresponding to torsional instability and lateral instability. Bounding the stable region can ensure that RPM values and WOB values that result in backward whirl or torsional stick-slip vibration are avoided during the drilling operation. Constraints508can be determined that further shrink a size of the stable region510. For example, the constraints508are shown to include an HMSE curve, a MSE curve, and a bit-wear ROP curve.

Points of (RPM, WOB) on the graph500that make up curves506correspond to resonance speed points, or combinations of WOB values and RPM values that result in a resonance speed. The resonance speed points on the curves506can be combinations of WOB values and RPM values that are to be avoided during a drilling operation. For examples, the curves506indicate combinations of WOB values and RPM values that may result in forward whirl for the drilling equipment, so any points on the curves506should be avoided to improve a drilling operation.

FIG.6is a block diagram of a system for determining parameters for a wellbore operation based on resonance speeds of drilling equipment according to one example of the present disclosure. A plot engine602can generate a plot that is usable in determining the drilling parameters. The plot engine602can receive real-time data610of a concurrently occurring drilling operation, wellbore parameters612for a wellbore associated with the drilling operation, and drilling information614. The real-time data610may include the wellbore parameters612, or the wellbore parameters612may be received separately from the real-time data610. The real-time data610and the wellbore parameters612can include a wellbore inclination, drilling depth, standpipe pressure, mud flow in, rate of penetration, torque, equivalent circulation density, or any other drilling data. The drilling information614can store an indication of a previously drilling depth at which a chart was generated for WOB values and associated RPM values that correspond to resonance speeds. The plot engine602may generate plot at predefined intervals of drilling depths, such as every ninety feet, so the plot engine602can receive the drilling information614and determine whether the predefined interval has occurred since a plot has been generated. If so, the plot engine602can use the real-time data610and the wellbore parameters612to generate a plot for a current drilling depth.

The plot generated by the plot engine602can be similar to the graph400or the graph500, in which one or more curves are generated of WOB values and associated RPM values that correspond to resonance speeds. The plot engine602can output the plot to a user interface620. An operator may interact with the user interface620and use the plot to determine drilling parameters for the drilling operation. For example, the operator can select a combination of a WOB value and an RPM value for the current drilling depth that does not appear along the curve of values that correspond with resonance speeds. In some examples, the plot engine602may determine the drilling parameters from the plot and automatically send the drilling parameters to the drilling equipment for the drilling equipment to implement in the drilling operation.

FIG.7is a flow chart of a process for determining parameters for a wellbore operation based on resonance speeds of drilling equipment according to one example of the present disclosure. In some examples, the computing device200inFIG.2can implement the process shown inFIG.7for effectuating some aspects of the present disclosure. Other examples can involve more operations, fewer operations, different operations, or a different order of the operations shown inFIG.7. The operations ofFIG.7are described below with reference to the components shown inFIG.2.

At block702, the computing device200can receive real-time data210for a drilling operation that is concurrently occurring with receiving the real-time data210. A sensing component positioned downhole in a wellbore in communication with the computing device200can collect the real-time data210and send the real-time data210to the computing device200. The real-time data210can include can include a wellbore inclination, drilling depth, standpipe pressure, mud flow in, rate of penetration, torque, equivalent circulation density, or any other drilling data.

At block704, the computing device200can determine, for a drilling depth, a RPM value212corresponding to a resonance speed based on a WOB value and the real-time data210. The drilling depth can be a current drilling depth indicated in the real-time data210. The WOB value may be a current WOB value indicated in the real-time data210, or may be any other WOB value the drilling equipment is capable of having. The computing device200can select the WOB value. The computing device200can determine, using the WOB value, at what RPM value a stress of the drilling system peaks, which can be the RPM value212that corresponds to the resonance speed. The computing device200may determine the RPM value212by generating a graph similar to the graph300inFIG.3.

At block706, the computing device200can generate a plot214of the WOB value and the RPM value212corresponding to the resonance speed. The plot214can be for the drilling depth and can include RPM values along an x-axis and WOB values along a y-axis. The WOB value and the RPM value212can be one resonance speed point on the plot214. The plot214can also include other resonance speed points of WOB values and associated RPM values that correspond to resonance speeds. Each WOB value may be associated with one or more RPM values that correspond to resonance speeds. In some example, the computing device200can also perform dynamic-stability analysis to determine a stable region of operation for drilling parameters of the drilling operation bounded by a torsional instability curve and a lateral instability curve. The computing device200can include an indication of the stable region on the plot214. Additionally, the stable region may be constrained based on an HMSE curve, a MSE curve, a bit-wear ROP curve, or a combination thereof.

At block708, the computing device200can determine drilling parameters216for the drilling operation based on the plot214. The drilling parameters216can exclude, for the WOB value, the RPM value212that corresponds to the resonance speed. The drilling parameters216can be selected from values within the stable region, but excluding combinations of WOB values and RPM values that are associated with a resonance speed. The computing device200may select an operating RPM value and an operating WOB value that are not associated with a resonance speed. For example, the computing device200may determine the operating WOB value to be the WOB value indicated in the real-time data210, and can determine the operating RPM value to be any RPM value in the plot214that is not associated with a resonance speed for the operating WOB value. The computing device200may automatically cause the drilling parameters216to be used in the drilling operation by sending the drilling parameters216to the drilling equipment as control setpoints for the RPM and the WOB.

In some aspects, a system, a method, and a non-transitory computer readable medium for determining drilling parameters for a wellbore operation based on resonance speeds are provided according to one or more of the following examples:

As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”).

Example 1 is a system comprising: a processing device; and a memory device that includes instructions executable by the processing device for causing the processing device to: receive real-time data for a drilling operation that is concurrently occurring with receiving the real-time data; determine, for a drilling depth, a rotations-per-minute (RPM) value corresponding to a resonance speed based on a weight-on-bit (WOB) value and the real-time data; generate a plot of the WOB value and the RPM value corresponding to the resonance speed; and determine drilling parameters for the drilling operation based on the plot, the drilling parameters excluding, for the WOB value, the RPM value corresponding to the resonance speed.

Example 2 is the system of example 1, wherein the memory device further includes instructions executable by the processing device for causing the processing device to: adjust the drilling operation to include the drilling parameters.

Example 3 is the system of examples 1-2, wherein the memory device further includes instructions executable by the processing device for causing the processing device to: determine, for the drilling depth and a plurality of WOB values, a plurality of RPM values corresponding to a plurality of resonance speeds, each WOB value of the plurality of WOB values associated with a corresponding RPM value of the plurality of RPM values, the plurality of WOB values including the WOB value, the plurality of RPM values including the RPM value, and the plurality of resonance speeds including the resonance speed; generate the plot by plotting, for each WOB value of the plurality of WOB values, the corresponding RPM value of the plurality of RPM values; and determine the drilling parameters for the drilling operation based on the plot, the drilling parameters excluding, for each WOB value of the plurality of WOB values, the corresponding RPM value of the plurality of RPM values.

Example 4 is the system of example(s) 1-3, wherein the memory device further includes instructions executable by the processing device for causing the processing device to: determine a stable region for the drilling parameters of the drilling operation; and determine the drilling parameters based on the stable region, the WOB value, and the RPM value corresponding to the resonance speed.

Example 5 is the system of example 4, wherein the memory device further includes instructions executable by the processing device for causing the processing device to determine the stable region by: constraining the stable region based on a maximum mechanical specific energy curve, a maximum hydro-mechanical specific energy curve, a bit-wear rotations-per-minute curve, or a combination thereof.

Example 6 is the system of example(s) 1-5, wherein the memory device further includes instructions executable by the processing device for causing the processing device to: output the plot to a user interface, the plot usable by an operator to determine the drilling parameters.

Example 7 is the system of example(s) 1-6, wherein the memory device further includes instructions executable by the processing device for causing the processing device to: determine, for the WOB value at the drilling depth, an additional RPM value that corresponds to another resonance speed is an outlier resonance speed; and remove the additional RPM value for the WOB value from the plot.

Example 8 is the system of example(s) 1-7, wherein the drilling parameters comprise an operating RPM value and an operating WOB value and the real-time data comprises a wellbore inclination, the drilling depth, standpipe pressure, mud flow in, rate of penetration, torque, and equivalent circulation density.

Example 9 is a method comprising: receive real-time data for a drilling operation that is concurrently occurring with receiving the real-time data; determine, for a drilling depth, a rotations-per-minute (RPM) value corresponding to a resonance speed based on a weight-on-bit (WOB) value and the real-time data; generate a plot of the WOB value and the RPM value corresponding to the resonance speed; and determine drilling parameters for the drilling operation based on the plot, the drilling parameters excluding, for the WOB value, the RPM value corresponding to the resonance speed.

Example 10 is the method of example 9, further comprising: adjusting the drilling operation to include the drilling parameters.

Example 11 is the method of example(s) 9-10, further comprising: determining, for the drilling depth and a plurality of WOB values, a plurality of RPM values corresponding to a plurality of resonance speeds, each WOB value of the plurality of WOB values associated with a corresponding RPM value of the plurality of RPM values, the plurality of WOB values including the WOB value, the plurality of RPM values including the RPM value, and the plurality of resonance speeds including the resonance speed; generating the plot by plotting, for each WOB value of the plurality of WOB values, the corresponding RPM value of the plurality of RPM values; and determining the drilling parameters for the drilling operation based on the plot, the drilling parameters excluding, for each WOB value of the plurality of WOB values, the corresponding RPM value of the plurality of RPM values.

Example 12 is the method of example(s) 9-11, further comprising: determining a stable region for the drilling parameters of the drilling operation; and determining the drilling parameters based on the stable region, the WOB value, and the RPM value corresponding to the resonance speed.

Example 13 is the method of example 12, wherein determining the stable region comprises: constraining the stable region based on a maximum mechanical specific energy curve, a maximum hydro-mechanical specific energy curve, a bit-wear rotations-per-minute curve, or a combination thereof.

Example 14 is the method of example(s) 9-13, further comprising: outputting the plot to a user interface, the plot usable by an operator to determine the drilling parameters.

Example 15 is the method of example(s) 9-14, further comprising: determining, for the WOB value at the drilling depth, an additional RPM value that corresponds to another resonance speed is an outlier resonance speed; and removing the additional RPM value for the WOB value from the plot.

Example 16 is a non-transitory computer-readable medium comprising instructions that are executable by a processing device for causing the processing device to perform operations comprising: receiving real-time data for a drilling operation that is concurrently occurring with receiving the real-time data; determining, for a drilling depth, a rotations-per-minute (RPM) value corresponding to a resonance speed based on a weight-on-bit (WOB) value and the real-time data; generating a plot of the WOB value and the RPM value corresponding to the resonance speed; and determining drilling parameters for the drilling operation based on the plot, the drilling parameters excluding, for the WOB value, the RPM value corresponding to the resonance speed.

Example 17 is the non-transitory computer-readable medium of example 16, further comprising instructions executable by the processing device for causing the processing device to: adjust the drilling operation to include the drilling parameters.

Example 18 is the non-transitory computer-readable medium of example(s) 16-17, further comprising instructions executable by the processing device for causing the processing device to: determine, for the drilling depth and a plurality of WOB values, a plurality of RPM values corresponding to a plurality of resonance speeds, each WOB value of the plurality of WOB values associated with a corresponding RPM value of the plurality of RPM values, the plurality of WOB values including the WOB value, the plurality of RPM values including the RPM value, and the plurality of resonance speeds including the resonance speed; generate the plot by plotting, for each WOB value of the plurality of WOB values, the corresponding RPM value of the plurality of RPM values; and determine the drilling parameters for the drilling operation based on the plot, the drilling parameters excluding, for each WOB value of the plurality of WOB values, the corresponding RPM value of the plurality of RPM values.

Example 19 is the non-transitory computer-readable medium of example(s) 16-18, further comprising instructions executable by the processing device for causing the processing device to: determine a stable region for the drilling parameters of the drilling operation; and determine the drilling parameters based on the stable region, the WOB value, and the RPM value corresponding to the resonance speed.

Example 20 is the non-transitory computer-readable medium of example 19, further comprising instructions executable by the processing device for causing the processing device to determine the stable region by: constraining the stable region based on a maximum mechanical specific energy curve, a maximum hydro-mechanical specific energy curve, a bit-wear rotations-per-minute curve, or a combination thereof.

The foregoing description of certain examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure.