WO2014062174A1

WO2014062174A1 - System and method for using mobile computing devices to select drill bits for wellbores

Info

Publication number: WO2014062174A1
Application number: PCT/US2012/060575
Authority: WO
Inventors: Gary Eugene Weaver; Thomas Goebel
Original assignee: Halliburton Energy Services, Inc.
Priority date: 2012-10-17
Filing date: 2012-10-17
Publication date: 2014-04-24

Abstract

Computer-implemented methods, computer-readable media, and computer systems for selecting drill bits for wellbores are described. A mobile computing device (100) receives geological data that describes a wellbore and drill bit data describing the drill bit (112) to drill a specified depth interval in the wellbore (110). The device determines lithology in the wellbore to be drilled to the specified depth interval using the wellbore data and the drill bit solution data. The device compares a theoretical wear rate of the drill with a historical wear rate of a drill bit used in an offset wellbore to determine a theoretical rate of penetration and theoretical drilling distance in the wellbore using the drill bit. In response to receiving input from an external device, the device provides providing the theoretical rate of penetration and the theoretical drilling distance.

Description

SYSTEM AND METHOD FOR USING MOBILE COMPUTING DEVICES TO SELECT DRILL BITS FOR WELLBORES

TECHNICAL FIELD

[0001] The present disclosure relates to computer-implemented methods, computer-readable media, and computer systems for using one or more mobile computing devices to select drill bits for wellbores.

BACKGROUND

[0002] A drilling rig used to drill wellbores is a portable factory for making deep holes in the ground. When a drill bit is pressed against the ground and rotated, the teeth on the bit grind and gouge the rock into small pieces. These pieces of rock or cuttings are moved out of the way so the drill bit's teeth can be constantly exposed to fresh, uncut rock. To do so, a liquid called drilling fluid or mud is used to move the cuttings away from the bit. A mud pump takes mud from mud tanks and pumps it under high pressure past the drill bit. Mud, exiting under pressure from jets in the drill bit clears the cuttings and moves them up an annulus of the wellbore hole. The cuttings are filtered out of the mud and the mud is returned to the mud tank for recirculation.

[0003] To operate a drilling rig efficiently, i.e., to optimize a speed at which the wellbore is drilled without wearing out the drill bit's teeth, an understanding of the geological environment through which the drill bit will drill is useful. Analyzing the strength of the rock in which the wellbore will be drilled can allow simulating, using computer systems, a drilling operation of a drill bit through the rock.

SUMMARY

[0004] The present disclosure describes computer-implemented methods, computer-readable media, and systems for using rock strength analysis to select drill bits for wellbores.

[0005] In general, one innovative aspect of the subject matter described here can be implemented as a computer-implemented method for selection of a drill bit solution for use in drilling a specified depth interval in a wellbore. A mobile computing device receives: (a) a drill bit selection query comprising a specified depth interval to analyze, (b) geological data for the selected depth interval, (c) drilling data for the specified interval comprising at least one of proposed mud weight, proposed pore pressure and weight on bit, torque on bit, or rotations per minute (RPM), and (d) bit characteristics comprising at least one of proposed drill-ability index, specific energy rating, or wear rating. The mobile device determines lithology for the selected depth interval. The mobile computing device receives a historical wear rate of another drill bit used in an offset well, said wear rate defined by degradation per interval foot. The mobile computing device determines a theoretical wear rate of a drill bit for use in drilling the specified depth interval. The mobile computing device compares the theoretical wear rate of the drill bit and the historical wear rate of the other drill bit to determine if the theoretical wear rate is less than the historical wear rate of the other drill bit. The mobile computing device determines a theoretical rate of penetration (ROP) and a theoretical drilling distance using the drill bit. The mobile computing device outputs data comprising the theoretical ROP and the theoretical drilling distance.

[0006] This, and other aspects, can include one or more of the following features. The mobile device can further determine overbalance for the specified depth interval using the received drilling data for the specified depth interval, rock strength for the specified depth interval using the received geological data for the specified depth interval, and mechanical specific energy (MSE) per unit volume of rock to be drilled in the specified depth interval using the received drilling data. The theoretical wear rate of the drill bit for use in drilling the specified depth interval can be determined using at least the previously calculated MSE. A subsequent drill bit selection query that includes selection criteria that are different from criteria received in the drill bit selection query can be received. A new theoretical wear rate of a revised drill bit that satisfies the selection criteria for use in drilling the specified depth interval using the previously calculated MSE can be determined. The new theoretical wear rate of the revised drill bit and the historical wear rate of the drill bit used in an offset well can be compared to determine if the new theoretical wear rate is less than the historical wear rate. A new theoretical ROP and a new theoretical drilling distance are determined for the revised proposed bit. In response to receiving the subsequent drill bit selection query, data comprising the new theoretical ROP and the new drilling distance are outputted to another mobile computing device. The data comprising the new theoretical ROP and the new theoretical drilling distance can be output to another mobile computing device. The selection criteria can be selected from a group comprising cutter density, blade count specific energy, drillability index, wear rate, blade profile, nozzle number and size, bit forces, steerability, face control and walk, gauge length, and cutter count. The mobile computing device can display the output data in response to the received drill bit selection query. Said wear rate can be based at least in part on ROP-to-torque ratio data for the offset well. Said wear rate can be determined by one or more of: an empirical calculation of the percentage of wear incurred by a bit in an offset well, based on dull condition included in a bit record; or application of wear rate to proposed bit, with appropriate adjustments for bit characteristics and application of parameters weight on bit (WOB) and rotations per minute (RPM), or interval length and changing formation type. Comparing the theoretical wear rate of the drill bit and the historical wear rate of the other drill bit can include determining wear rate of the drill bit, and plotting the determined wear rate over a wear rate curve of the drill bit from the offset well. The geological data can be stored on a hardware storage device. Receiving the geological data can include reading the data from the hardware storage device. The geological data can be received over the data network either automatically or by interrogation. Receiving the geological data over the data network automatically can include detecting a connection to the data network, and in response to detecting the connection to the data network, automatically triggering transmission of the geological data over the data network. The data network can be a cellular network. The geological data can be received over the cellular network. Receiving the geological data over the cellular network can include forming a connection with a server computer system that hosts a website, and triggering transmission of the geological data over the cellular network upon logging on to the website. Receiving the geological data can include reading the geological data upon determining that the mobile computing device is within a wireless network signal zone at a drilling site. An automatic download of the geological data can be triggered upon determining that the mobile computing device is within the wireless network signal zone. Determining the rock strength can include determining upper and lower limits of gamma ray log; and using the upper and lower limits to define 100% concentration values of shale and non-shale. Log data can be stretched or compressed between two given points in space for a nearby well to conform to the geological model generated for a proposed well. The stretching or compressing can be repeated until the entire interval of the proposed well is modeled. Porosity can be determined from user- selected log(s) according to Wyllie's Equation. Receiving drilling data for the specified depth interval further can include receiving a description of drill bit characteristics for multiple drill bits. Receiving drilling data for the specified depth interval can include receiving drilling fluid characteristics and rheology from the wellbore. The MSE per unit volume of rock to be drilled in the specified depth interval can be determined using the description of drill bit characteristics or the drilling fluid characteristics and rheology. The mobile computing device can access data stored in a computer system. The stored data can include at least one drill bit selection that satisfies the drill bit query and associated rock strength, MSE and proposed performance criteria comprising theoretical wear rate, theoretical ROP and theoretical time drilling the specified depth interval in the proposed wellbore for the at least one bit. The mobile computing device can receive actual drilling data for at least a portion of the specified interval that has been drilled in the wellbore. The mobile computing device can compare the received actual data to the accessed stored data, and output differences between the actual data and the accessed stored data. The mobile computing device can determine adjustments to drilling conditions based on the differences between the actual data and the accessed stored data, and can transmit the adjustments. Transmitting the adjustments can include transmitting the adjustments to at least one of a driller, a computer system that operates the drill bit, or a bottom hole assembly that includes the drill bit. The adjustments can include at least one of a change of a drilling condition or an instruction to remove the drill bit from the wellbore. Said at least one drill bit selection that satisfies the drill bit query and the associated rock strength, MSE and proposed performance criteria including theoretical wear rate, theoretical ROP and theoretical drilling distance in the proposed wellbore for the at least one bit can be stored in the computer system. A difference includes a difference between 5 and 10 percent between the actual data and the accessed stored data. Said actual drilling data received can include at least one or more of WOB, RPM, flowrate, circulating mud pressure, and torque. The mobile computing device can receive a revised drill bit selection inquiry including a revised depth interval. The mobile computing device can determine a revised MSE per unit volume of rock to be drilled in the revised depth interval. The mobile computing device can determine a revised theoretical wear rate of the revised drill bit for use in drilling the specified depth interval using the revised MSE. The mobile computing device can determine a revised theoretical ROP and revised theoretical drilling distance in the wellbore for the revised proposed bit. The mobile computing device can output the revised theoretical ROP and revised theoretical drilling distance in the wellbore for the revised proposed bit. The mobile computing device can include at least one of a smart phone, a tablet computer, a laptop computer, or a personal digital assistant. Receiving the actual drilling data can include downloading the actual drilling data via a communications protocol. Receiving the actual drilling data can include receiving the actual drilling data in real time. The geological data can be received from instruments. The data can be output over a data network.

[0007] Another innovative aspect of the subject matter described here can be implemented as a computer-implemented method that includes generating, by at least one computer, in response to a drill bit selection query, instructions to cause rendering of a graphical interface on a display, the graphical interface comprising at least one selectable control; detecting a selection of the at least one selectable control; in response to detecting the selection, determining: rock strength for a depth interval using geological data for the specified depth interval, lithology for the depth interval, mechanical specific energy (MSE) per unit volume of rock to be drilled in the specified depth interval using drilling data, a theoretical wear rate of a drill bit for use in drilling the specified depth interval using the (MSE); and a theoretical ROP and theoretical drilling distance in the wellbore for the proposed bit, and displaying, in the graphical interface, at least one drill bit solution for drilling the specified interval, the theoretical ROP and theoretical drilling distance in the wellbore. [0008] This, and other aspects, can include one or more of the following features. The method can further include receiving, in the graphical user interface, a revised drill bit selection inquiry; and receiving another selection of the at least one control after receiving the revised drill bit selection query; in response to receiving the other selection, determining: a revised rock strength for the depth interval by the computing device using geological data for the specified depth interval, a revised mechanical specific energy (MSE) per unit volume of rock to be drilled in the specified depth interval using drilling data, a revised theoretical wear rate of the drill bit for use in drilling the specified depth interval using the previously calculated (MSE); and a revised theoretical ROP and theoretical period of time drilling the specified depth interval in the wellbore for the proposed bit; and displaying, in the graphical interface, at least one revised drill bit solution for drilling the specified interval, the revised theoretical ROP and the revised theoretical period of time drilling the specified depth interval in the wellbore for the revised proposed bit. The method can further include displaying, in the graphical user interface, one or more fields to receive at least one drill bit selection criteria, wherein the selection criteria includes at least one of a cutter density or a blade count. The method can further include displaying, in the graphical user interface, a plurality of objects, each object representing an input option that corresponds to a respective drilling condition parameter; receiving, in the graphical user interface, a selection of a particular object of the plurality of objects, the particular object representing a particular input option; and in response to receiving the selection of the particular object, displaying, in the graphical user interface, a control object representing a controller to control a particular drilling condition parameter to which the particular input option corresponds. The method can further include displaying, in the graphical user interface, a plurality of objects, each object representing an output option that corresponds to a respective revised drill bit solution; receiving, in the graphical user interface, a selection of a particular object of the plurality of objects, the particular object representing a particular output option; and in response to receiving the selection of the particular object, displaying, in the graphical user interface, an output object that includes the particular output option. [0009] A further innovative aspect of the subject matter described here can be implemented as a computer-implemented method for selection of a drill bit for use in drilling a specified depth interval in a wellbore. The method includes receiving, by a mobile computing device, wellbore data including geological data that describes a wellbore and drill bit data describing the drill bit to drill a specified depth interval in the wellbore; determining, by the mobile computing device, lithology, overbalance, and rock strength for the specified depth interval, and mechanical specific energy (MSE) per unit volume of rock in the wellbore to be drilled to the specified depth interval using the wellbore data and the drill bit solution data; determining, by the mobile computing device, a theoretical wear rate of the drill, at least in part, using the MSE; obtaining, by the mobile computing device, a historical wear rate of a drill bit used in an offset wellbore, the historical wear rate describing wear of a drill bit used to drill the offset wellbore; determining, by the mobile computing device, a theoretical rate of penetration and theoretical drilling distance in the wellbore using the drill bit, wherein the theoretical rate of penetration and the theoretical drilling distance is determined, in part, by comparing the theoretical wear rate and the historical wear rate; and in response to receiving input from an external device connected to the mobile computing device, providing the theoretical rate of penetration and the theoretical drilling distance.

[0010] This, and other aspects, can include one or more of the following features. The drill bit data can include at least one or more of a cutter density, a blade count specific energy, a drillability index, a wear rate, a blade profile, a nozzle number and size, bit forces, steerability, face control and walk, a gauge length, and a cutter count. Providing the theoretical rate of penetration and the theoretical drilling distance can include transmitting the theoretical rate of penetration and the theoretical drilling distance in to the external device over a network. The network can be a packet-switched data network. Providing the theoretical rate of penetration and the theoretical drilling distance can include displaying the theoretical rate of penetration and the theoretical drilling distance in a user interface connected to the mobile computing device. Providing the theoretical rate of penetration and the theoretical drilling distance can include detecting, by the mobile device, a connection to a data network, and in response to detecting the connection, transmitting the theoretical rate of penetration and the theoretical drilling distance over the network. The method can further include receiving the input from the external device after detecting the connection. The wellbore data and the drill bit data can be received by the mobile computing device over the network. The wellbore data and the drill bit data can be received from a computer-readable storage device that stores the wellbore data and the drill bit data.

[0011] While generally described as computer- implemented software embodied on tangible media that processes and transforms the respective data, some or all of the aspects may be computer-implemented methods or further included in respective systems or other devices for performing this described functionality. The details of these and other aspects and implementations of the present disclosure are set forth in the accompanying drawings and the description below. Other features and advantages of the disclosure will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 illustrates an example of a mobile computing device to communicate with computer systems implemented at a wellbore.

[0013] FIGS. 2A, 2B, and 2C illustrate examples of user interfaces to receive a drill bit selection query, geological data, drilling data, and bit characteristics.

[0014] FIG. 3 illustrates an example of a user interface to display parameters of the wellbore determined based on the input received through the user interfaces shown in FIGS. 2A and 2B.

[0015] FIGS. 4A and 4B illustrate examples of user interfaces to display theoretical bit data.

[0016] FIG. 5 illustrates an example of a mobile computing device communicating with the computer systems implemented at the wellbore.

[0017] FIGS. 6A and 6B are flowcharts of an example process for recommending drill bits for wellbores.

[0018] FIG. 7 is a flowchart of an example process for providing the theoretical rate of penetration and the theoretical wear expectation for drilling a wellbore. [0019] Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0020] This disclosure describes computer-implemented methods, computer- readable media, and computer systems for using rock strength analysis to select drill bits for wellbores. In some implementations, a mobile computing device (for example, a smart phone, a tablet computer, a laptop computer, a personal digital assistant, and the like) can be configured to execute computer software applications that can determine an initial in situ rock strength of a geological environment in which a wellbore is to be drilled. The mobile computing device can further be configured to receive additional inputs including a specified depth interval, drilling data, and bit characteristics. The mobile computing device can also be configured to receive parameters describing a previously drilled wellbore and the drill bit used to drill the previous wellbore. The mobile computing device can implement, for example, in real time, computer applications that can compute a theoretical wear rate of a drill bit with a historical wear rate of the drill bit used to drill the previous wellbore. Based on the determination, the mobile computing device can provide a theoretical rate of penetration (ROP) and a theoretical wear expectation (i.e., the estimated distance the bit will drill) for drilling the specified depth interval using the drill bit.

[0021] In some implementations, the mobile computing device can be configured to display one or more user interfaces (for example, graphical user interfaces) into which a user can input parameters describing the geological environment in which the wellbore is to be drilled and characteristics of a drill bit for drilling the wellbore. The mobile computing device can also be configured to display the output of the rock strength analysis calculations and characteristics of the drill bit in respective user interfaces.

[0022] As drilling of the wellbore progresses, the mobile computing device can be configured to periodically receive data describing characteristics of the wellbore, for example, over one or more wired or wireless networks, such as the Internet or cellular telephony networks (or combinations of them). The mobile computing device can additionally receive data from wellbore telemetry connecting sensors at the bit or other positions within the wellbore from instruments, for example, monitor while drilling (MWD) instruments, wired pipes, and the like. The mobile computing device can also be configured to determine a wear rate of the drill bit based on the received data and compare the wear rate with historical wear rate of the previously drilled wellbore under similar drilling circumstances. The mobile computing device can be configured to revise drilling parameters and to transmit the revised drilling parameters to the wellbore over the one or more wired or wireless networks. In this manner, the drilling operations can be periodically revised, if needed, to optimize drill bit efficiency and drilling speed, and to adjust changing circumstances.

[0023] Implementing the techniques described in this disclosure can provide one or more of the following potential advantages. The mobile computing device can be portable, allowing use of the device and access to the data provided by the device, both onsite and off-site, from the wellbores, for example, in offices, homes, and the like. Users of the device can view a catalog including multiple drill bits having a range of drilling characteristics using the device. Because the device's user interfaces enable the user to input and output multiple drilling parameters, the need for an interpretive analyst can be decreased or eliminated. Because in some implementations the user is provided with periodic updates about the wellbore being drilled on the user's device, the user can responsively provide instructions to change drilling conditions using the device itself. In addition, the user can make quick adjustments to the drilling environment using the device itself.

[0024] In situations in which the user is a vendor providing drilling services to a customer, the customer can be granted access to all or portions of the data that the vendor can access at one or more or all of the vendor's facilities. The mobile computing device can continuously determine, receive, and transmit the data in substantially real time. In some situations, alerts representing drilling conditions can be sent to the vendor who can communicate the alerts to the customer or directly to one or more or all customers (or combinations of them). This can permit a user to view the real time data and understand reasons for which changes in drilling conditions, if any, are being recommended. In this manner, the mobile computing device can be implemented as a high-end, data gathering and telecommunication solution, which is a single receiving point of all rig-related data for drilling tool bits.

[0025] FIG. 1 illustrates an example of a mobile computing device 100 to communicate with computer systems implemented at a wellbore. In other implementations the computer system may be located remotely from the wellbore. In some implementations the device may be hand-held and shaped and/or sized similar to a cellular phone or pocket calculator. The device 100 can be a computer system that includes a data processing apparatus 102 configured to execute computer software instructions stored on a computer-readable medium 104 to perform operations for selection of a drill bit solution for use in drilling a specified depth interval in the wellbore. The device 100 can be connected to one or more computer systems or computer-readable storage devices (or both) implemented at the wellbore over one or more networks 108, for example, the Internet, cellular telephony networks, Wi-Fi, WWAN, and the like. Through the networks 108, the device 100 can transmit drilling conditions determined based on drilling parameters received from a user to computer systems implemented at the wellbore. The device 100 can further receive updates describing the drilling parameters from the computer systems and revise the drilling conditions based on the updates.

[0026] The drilling parameters can include in situ rock strength of a wellbore 110 to be drilled in a geological environment (i.e., one or more geologic formations or portions thereof) 114 and characteristics of a drill bit 112 used to drill the wellbore 110. In some implementations, the mobile computing device 100 can execute computer software instructions stored on a computer-readable medium to determine the in situ rock strength of the wellbore 110 and the characteristics of the drill bit 112. To determine the in situ rock strength and the drill bit characteristics, the mobile computing device 100 can receive input including drilling parameters (described below) through one or more user interfaces (for example, the user interface 132). The mobile computing device 100 can provide the rock strength analysis and the characteristics of the drill bit to an on-site server computer system 106 over the one or more networks 108. For example, the mobile computing device 100 can execute computer software instructions to identify a drill bit solution that identifies a drill bit 112 and drilling conditions based on the drilling parameters received through the user interfaces. When the mobile computing device 100 provides the drill bit solution and the drilling conditions to the on-site server computer system 106, the site operators can use the drill bit 112 to drill the wellbore 110 in the geological environment 114 according to the drilling conditions. In other implementations the device 100 instead of or in addition to communicating with a server located at a well site may communicate with a server remote from the well site.

[0027] As the wellbore 110 is being drilled, the performance of the drill bit 112 used to drill the wellbore 110 and the characteristics of the wellbore 110 can be periodically measured using multiple measuring instruments (for example, a first instrument 116, a second instrument 118, and the like). The instruments can include, for example, gamma ray tools, density tools, weight-on-bit indicators, rotational speed measurement tools, torque -on-bit indicators, logging while drilling (LWD) instruments, multivariate optical element (MOE) instruments, formation characteristic measurement instruments, and the like. The instruments can be positioned proximal to or within the wellbore 110, the drill bit 112 or the ground in the geological environment 114. Using the instruments, parameters of the wellbore, for example, porosity, lithology, and the like, and parameters of the drill bit, for example, wear rating, specific energy rating, and the like, can be periodically determined. The instruments can be connected to a computer- readable storage device 128 either directly or through one or more networks 120, 130 (for example, the Internet, Wi-Fi, WWAN, intelligent wired drill pipe, and the like), and can transmit the measured data to the storage device 128. The storage device 128 can include one or more of a non-volatile secure digital (SD) card, external drives, flash drives, hard drives, computer-readable memory chips, and the like. Additional examples of the storage device 128 are provided below. The mobile computing device 100 can receive the measured data either directly from the storage device 128 or from the server computer system 106 to which the storage device 128 transmits the measured data.

[0028] In some implementations, the mobile computing device 100 can additionally receive parameters describing another drill bit that was used to previously drill another wellbore 122. For example, the other wellbore 122 may have been drilled in a geological environment that shares some similarities with the geological environment 114 in which the wellbore 110 is being drilled. When the other wellbore 122 was being drilled, parameters describing the wellbore 122 and the drill bit used to drill the wellbore 122 (not shown) may have been collected using respective instruments (for example, a first instrument 124, a second instrument 126, and the like), and transmitted to the computer-readable storage device 128 or the server computer system 106 (or both). The device 100 can retrieve the stored parameters describing the drill bit used to previously drill the other wellbore 122 through either of these sources. The device 100 can determine a historical wear rate of the drill bit used to drill the wellbore 122 from the retrieved parameters. In some implementations, the device 100 can additionally present the retrieved data through one or more user interfaces for a user to view. By comparing the historical wear rate with a theoretical wear rate of the drill bit 112 as the wellbore 110 is being drilled, the device 100 can determine and provide revised drilling parameters to the server computer system 106, which, in turn, can be implemented to further drill the well 122.

[0029] FIGS. 2A, 2B, and 2C illustrate examples of user interfaces to receive a drill bit selection query, geological data, drilling data, and bit characteristics. In some implementations, the mobile computing device 100 can execute one or more computer software applications that display multiple input screens (for example, a first input screen 220, a second input screen 222) in the user interface 132. In each input screen, the device 100 can display multiple control fields, for example, a first text box 204, a second text box 206, a third text box 208, a drop-down table 210 that includes multiple selectable fields 212, 214, 216, 218, and the like. In each input screen, the device 100 can display selectable control buttons, for example, a "BACK" button, a "NEXT" button, and the like. To select a control field, a user of the device 100 can provide either a touch input to a touch screen included in the device or select a hard key, for example, the key 202. For example, in response to detecting a selection of the "NEXT" button displayed in the first input screen 220, the device 100 can display the second input screen 222 instead of the first input screen 220. In the second input screen 222, the device 100 can display more control fields, for example, text boxes 224, 226, selectable radio buttons, and the like.

[0030] Through the control fields included in the multiple input screens, the mobile computing device 100 can receive, from a user, a drill bit selection query, geological data, drilling data, and bit characteristics. The drill bit selection query can include a specified depth interval for analysis. The geological data for the selected depth interval can be received from instruments. The drilling data for the specified interval can be selected from the group consisting of proposed mud weight, proposed pore pressure and weight on the bit, torque on the bit, and rotations per minute (RPM). The bit characteristics can be selected from the group consisting of proposed drillability index, specific energy rating, wear rating, design, anticipated formation interaction, and distance the bit is expected to drill in a specified geological environment (i.e., geological formation(s) or interval(s)). In some implementations, the device 100 can receive portions of the aforementioned data from the computer-readable storage device 128. For example, the storage device 128 can store the geological data. The device 100 can receive the geological data from the storage device 128 over the one or more networks 108. Receiving drilling data for the specified depth interval can further include receiving a description of drill bit characteristics for multiple drill bits and characteristics of a drilling fluid and rheology for the wellbore 110.

[0031] As described above, the inputs into the multiple control fields in the multiple input screens represents inputs describing the drilling parameters to drill the wellbore 110 with the drill bit 112. In one of the input screens, for example, the last input screen, the device 100 can include a "CALCULATE" control button 228. In response to detecting a selection of the "CALCULATE" button 228, the mobile computing device 100 can determine drilling conditions including the in situ rock strength analysis and the characteristics of the drill bit 1 12. In some implementations, for the specified depth interval, the device 100 can determine an overbalance using the received drilling data, a rock strength and lithology using the received geological data, and mechanical specific energy (MSE) per unit volume of rock to be drilled using the received drilling data. In addition, the device 100 can determine upper and lower limits of the gamma ray log, and, using the upper and lower limits, can define 100% concentration values of shale and non-shale. The device 100 can determine a shale reference value for an interval based on the gamma ray log from the previously drilled wellbore 122 and determine the gamma value at which the rock type is 100% shale. The device 100 can determine the minimum value to be the value at the point at which the rock type has no trace of shale (i.e., is all non-shale), and the maximum value to be the value which will exceed the actual maximum value of the gamma ray log. The reference value for the non-shale can be equivalent to the minimum value for the shale, the non- shale maximum can be equivalent to the shale reference value, and the non-shale minimum can be zero. In summary, the device 100 can determine the minimum shale value of gamma ray log to be a value at which the non- shale is at a maximum concentration, and the maximum non-shale value to be a value at which the shale is at a maximum concentration.

[0032] The mobile computing device 100 can additionally stretch or compress log data between two given points in space for the previously drilled wellbore 122 to conform to the geological model generated for the wellbore 110. Stretching and compressing can allow updating logs/data for model revision to the proposed wellbore 110 as new information becomes available as drilling progresses. The device 100 can enable a user to select, in one or more of the input screens, points on logs of the previously drilled wellbore 122 at which the logs deviate from logs for the wellbore 110 as updated information about trigger events become available. Once new points in space or time (i.e., z-direction) are identified for a given event, the device 100 can stretch or compress the log to force the event in the wellbore 122 to match the event for the wellbore 110 that is currently being drilled. The device 100 can further repeat the stretching or compressing until the entire interval of the wellbore 110 has been modeled. In some implementations, the device 100 can determine porosity from user-selected logs according to Wyllie's Equation. For example:

Sonic porosity = (At_log - At_matrix)/ (At_form - At_matrix).

[0033] In some implementations, the mobile computing device 100 can determine the MSE per unit volume of rock to be drilled in the specified depth interval using the description of drill bit characteristics or the drilling fluid characteristics and rheology. The computer-readable storage device 128 can store data including at least one drill bit selection that satisfies the drill bit query and associated rock strength, mechanical specific energy, and proposed performance criteria. The criteria can include theoretical wear rate, theoretical ROP, and theoretical time drilling the specified depth interval in the proposed wellbore for the at least one drill bit. Separately, the device 100 can receive actual drilling data for at least a portion of the specified interval that has been drilled in the wellbore 110. The device 100 can compare the received actual data to the stored data accessed from the storage device 128. The device 100 can output differences between the actual data and the accessed stored data, for example, in output screens (described below) displayed in the user interface 132.

[0034] The computer-readable storage device 128 can store at least one drill bit selection that satisfies the drill bit query and also store the associated rock strength, MSE, and proposed performance criteria that includes the theoretical wear rate, theoretical ROP, theoretical time drilling the specified depth interval, and the theoretical distance to be drilled ("drilling distance") in the wellbore 110 for the at least one bit. The mobile computing device 100 can determine that the actual data (i.e., data for the wellbore 110 being drilled) differs from the accessed data (for example, theoretical data) if the device 100 determines a difference of between 5% and 10% between the actual and accessed data. Actual drilling data received can include at least one or more of weight on bit (WOB), ROP, flowrate, circulating mud pressure, and torque.

[0035] In some implementations, the mobile computing device 100 can receive, for example, from the computer-readable storage device 128 or the server computer system 106 (or remote server system), a historical wear rate of another drill bit used in an offset well (i.e., the previously drilled wellbore 122). The wear rate can be defined by degradation per interval foot and can be based at least in part on ROP-to -torque ratio data for the offset well. This can include empirical calculation of the percentage of wear incurred by a bit in the wellbore 122, based on dull condition reported in the bit record or other report, and application of wear rate to proposed bit with appropriate adjustments for bit characteristics and application of parameters WOB and RPM. Similarly, adjustments can also be made for interval length and changing formation type. An ROP-to-Torque ratio can be used to gauge the amount of wear incurred in the bit used in the wellbore 122 for re-application to expected wear in the proposed bit for the wellbore 110. ROP can be inversely proportional to torque.

[0036] FIG. 2C displays a user interface 230 using which a user can provide input to control drilling conditions. The device 100 can display the user interface 230, for example, in response to receiving input from the user. In the user interface 230, the device 100 can display multiple input options (for example, input options 232, 234, 236, and 238), each of which represents a respective drilling condition parameter. Each drilling condition parameter can be an input that an operator can control while performing a drilling operation in the wellbore 110. Through the user interface 230, the device 100 can enable the user to control the drilling condition parameters. To do so, the device 100 can display multiple control objects (for example, control objects 242, 246) in a portion 231 of the user interface 230. The control objects can represent controllers, and can include, for example, an object with one or more slider bars, an input dial, and the like.

[0037] In some implementations, a user can select an input option, for example, input option 234 representing "geological data," using an input device such as a cursor 240. The device 100 can be configured to receive input using any type of input device including a touch input, a voice input, and the like. The device 100 can associate the selected input option with a respective control object. In response to detecting that the user has selected input option 234, the device 100 can identify a corresponding control object, and display the control object in the portion 231 of the user interface 230. For example, if the device 100 displays control object 242 which includes slider bars, then the user can control the slider bars to provide geological data input. The device 100 can transmit the input that the user provides to an operator at the wellbore 110 who can perform the drilling operations according to the received input. In some implementations, the device 100 can receive a first selection of an input option (for example, input option 236) and a second selection of a control object (for example, control object 246), and responsively display the selected control object in the portion 231 to enable a user to control the selected input option. Using the control objects, the user can provide real time input to control the drilling operations.

[0038] In some implementations, the mobile computing device 100 can compare the theoretical wear rate (i.e., distance to be drilled) of the drill bit to be used in drilling the wellbore 110 and the historical wear rate (i.e., drilled distance) of the other drill bit used to previously drill the wellbore 122. Based, in part, on the comparison, the device 100 can determine a theoretical rate of penetration (ROP) and a theoretical distance drilled using the drill bit. In some implementations, the device 100 can present each drilling condition in a respective control field in an output screen. For example, the device 100 can display the overbalance, rock strength, mechanical specific energy, theoretical and historical wear rates in respective control fields - control fields 304, 306, 308 - in one or more output screens, such as output screen 302, displayed in the user interface (FIG. 3). In control fields - for example, control fields 404, 406, 408 - displayed in a different output screen 402 (FIGS. 4A, 4B), the device 100 can display data describing the offset well (i.e., the wellbore 122) and the theoretical bit data - the theoretical ROP and the theoretical distance to be drilled. In addition, the device 100 can output the data comprising the theoretical ROP and the theoretical distance to be drilled over a data network, for example, the networks 108, to one or more computer systems, for example, the server computer system 106. Operators on-site at the wellbore 110 can receive the determined drilling conditions and drill the wellbore 110 accordingly. In addition, the device 100 can transmit instructions to the computer-readable storage device 128 to store the drilling conditions.

[0039] FIG. 4B is an example of a user interface 410 in which the device 100 can display multiple objects (for example, objects 414, 416, 418), each representing an output option 412 that corresponds to a respective drill bit solution. For example, in the objects, the device 100 can display lithology, overbalance, rock strength, actual wear rate, and the like. A user can select an output option, for example, using a cursor or a touch selection or a voice input. In response to receiving a selection of a particular object displayed in the graphical user interface 410, the device 100 can display, in the portion 411 of the graphical user interface 410, an output object that includes the particular option. An output object can be a line chart 420, a bar graph 422, a pie chart 424, or any visual aid that allows the user to visually observe the drill bit solution. For example, the output object can be a line chart that displays a weight on bit over time or a bar graph that displays a torque on bit over time or a visual representation of the geological formation in which the wellbore is being drilled. In this manner, the device 100 can enable the user to view an output option in any visual representation that the user prefers. Further, the device 100 can periodically (for example, continuously) update the output object to reflect data that the device 100 receives in real time.

[0040] In some implementations, the mobile computing device 100 can receive data measured by the measuring instruments over the one or more networks 108. Using the measured data, the device 100 can revise the drilling conditions for drilling the wellbore 110. Alternatively, or in addition, the device 100 can receive a subsequent drill bit selection query that can include selection criteria that are different from criteria previously received in the drill bit selection query. For example, the device 100 can receive the subsequent drill bit selection query from the server computer system 106 (or remote server system). The device 100 can determine a new theoretical wear rate of a revised drill bit that satisfies the selection criteria for use in drilling the specified depth interval using the previously calculated MSE. The device 100 can compare the theoretical wear rate of the revised drill bit and the historical wear rate of the drill bit used in the wellbore 122. Based on the comparison, the device 100 can determine that the wear rate of the drill bit used to drill the wellbore 110 is less than that of the drill bit that was used to drill the wellbore 122. If so, then continued drilling of the wellbore 110 under the drilling conditions can improve drilling efficiency and duration of run. If not, then the device 100 can determine revised drilling conditions to improve the efficiency and the run duration.

[0041] If the device 100 determines that the wear rate (i.e., distance to be drilled) of the drill bit used to drill the wellbore 110 is less than that of the drill bit that was used to drill the wellbore 122, the device 100 can determine a new theoretical ROP and a new theoretical distance to be drilled ("drilling distance") for the revised drill bit. In response to receiving the subsequent drill bit selection query, the device 100 can output the data comprising the new theoretical ROP and the new theoretical drilling distance to another mobile computing device or to the server computer system 106 or to the computer- readable storage device 128 over the one or more networks. The on-site operators can revise the drill conditions to drill the wellbore 110 based on the new theoretical ROP and the new theoretical drilling distance. The selection criteria can be selected from a group that includes cutter density, blade count specific energy, drillability index, wear rate, blade profile, nozzle number and size, bit forces, steerability, face control and walk, gauge length, and cutter count. In addition to outputting the data over the network, the device 100 can display the data in one or more output screens.

[0042] FIG. 5 illustrates an example of a mobile computing device 100 communicating with the computer systems (for example, the server computer system 106 (or remote server system), another mobile computing device, the computer-readable storage device 128) implemented at the wellbore 110. As described above, the device 100 receives input through control fields in input screens displayed in the user interface 132, determines drilling conditions, and provides the drilling conditions to the computer systems on-site at the wellbore 110. The device 100 can be configured to execute the instructions to present the input screens in the user interface 132 regardless of whether the device 100 is within a range of the networks 108. For example, a user of the device 100 can be in an office far removed from the site of the wellbore 110, provide input to cause the device 100 to execute the computer software application, and provide drilling parameters and the geological data into the input screens. The device 110 can be connected to a network, for example, the Internet, and can automatically transmit the received data over the network to the on-site computer systems. In some implementations, the device 110 can store the received data and transmit the data upon receiving input from the user to do so. The user can provide the input either immediately after providing the data or at a later time.

[0043] In some implementations, the device 100 can determine a technical limit that describes the most efficient drilling conditions that can be employed using a drill bit of known characteristics and at a wellbore in a known geological environment. For example, the device 100 can determine the technical limit based on the input data received through the interfaces described above with reference to Figs. 2A-C. Having determined and stored the technical limit, the device 100 can periodically (for example, continuously) compare actual drilling conditions with the most efficient drilling conditions described in the technical limit. The difference between the actual drilling conditions and the technical limit can represent an inefficiency of the drilling system. Such an inefficiency can be a result of one or more of the drill bit, the geological environment, or devices employed during drilling. For example, the technical limit may be determined based on a rating of a mud pump. But, the mud pump may actually operate at less than its rating, for example, due to faulty maintenance. In this example, the inefficiency of the drilling system can be caused, in part, by the mud pump.

[0044] Upon determining an inefficiency of the drilling system, the device 100 can implement instructions to probe one or more or all of the components of the drilling system. For example, the device 100 can implement instructions to compare an actual performance of each component with a rated performance of the component. By doing so, the device 100 can identify one or more components in the drilling system that cause the inefficiency. Responsively, the device 100 can notify a rig operator (or a controller of a responsible component) about the cause of the inefficiency. The device 100 can further receive responses from the rig operator or the controller about changes (for example, repairs, replacements, and the like) to the responsible component. The device 100 can determine a revised technical limit and continue to monitor actual drilling conditions, as described above.

[0045] In some implementations, the user can transport the mobile computing device 100 that includes the input data on-site. When the device 100 is outside the range of the networks 108, then the device 100 may not transmit any data to the on-site computer systems. Once the device 100 enters the range of the networks 108, then the device 100 can detect a connection to the data network, and, in response to detecting the connection to the data network 108, can trigger transmission of the geological data and other data received through the input screens over the data network 108 to the on-site computer systems. For example, the device 100 can automatically transmit the data upon detecting the connection. Alternatively, or in addition, the server computer system 106 can detect that the device 100 is connected to the network 108 and can interrogate the device 100 requesting the data. In some implementations, the device 100 can execute authentication protocols to authenticate the device 100 as being authorized to form a connection with the network 108. For example, the authentication protocols can cause a webpage of website to be presented into which the user can present authentication information - log-in and password - to authenticate the device 100. In implementations in which the network 108 is a cellular network, a cellular network tower (not shown) can be installed on-site which can detect that the device 100 has entered the range of the network 108.

[0046] In some implementations, the on-site computer systems can receive the drilling data and the geological data (for example, surface data or down hole data, or both) by reading the drilling data or the geological data (or both) upon determining that the mobile computing device 100 is within a wireless network signal zone on-site. In such implementations, the network 108 can be a Wi-Fi network. Multiple other devices can be connected to the network 108. For example, the multiple other devices can each be connected to a central server device such as the server computer system 106. Alternatively, or in addition, the multiple other devices can be connected to each other as long as the devices are within a range of the network 108. When the mobile computing device 100 enters the range of the network 108, other devices connected to the network 108 can detect a connection of the device 100 to the network and can receive data directly from the device 100. For example, a user of another mobile computing device that is connected to the network 108 can automatically receive the geological data and the drilling conditions from the mobile computing device 100 when the user of the device 100 transports the device 100 within the range of the network 108. To do so, the devices connected to the network 108 can implement a "handshake" or similar protocols that enable data transfer between the devices.

[0047] In some implementations, one or more of the multiple other devices (and the server computer system 106) can continuously search for the mobile computing device 100. Upon detecting that the device 100 has formed a connection to the network 108, the other devices can automatically trigger a download of the geological data and the drilling conditions from the device 100.

[0048] Similarly to transmitting data over the network 108, either automatically or responsive to requests, the device 100 can receive data from multiple other devices (and the server computer system 106, (or remote server system)) over the network 108. For example, the device 100 can receive the actual drilling data from another mobile computing device or the server system 106 (or remote server system), or the computer- readable storage device 128 (or combinations of them), either automatically or responsive to one or more requests. The device 100 can also receive the actual drilling data even when it is not within a range of the network 108, for example, over the Internet.

[0049] In some implementations, the device 100 can receive the data from the multiple other devices in real time. In real time processing, data is received, recorded, and processed as an event occurs. In the context of actual geological data, as the measuring instruments measure the actual geological data and transmit the measured data to either the server computer system 106, the computer-readable storage device 128, or other mobile computing devices, the actual geological data is transmitted to the mobile computing device 100 without any appreciable time delay between receipt of the data by the other devices and transmission of the data to the device 100. In sum, as soon after the measuring instruments measure the actual geological data as possible, the device 100 receives the data.

[0050] In some implementations, multiple other devices (for example, devices similar to device 100) can receive all or portions of the data that device 100 can receive. For example, the device 100 can be operated by a drilling services provider and one or more of the multiple other devices can be operated by customers that receive drilling services from the provider. The drilling services provider can establish a network of other devices, and authenticate each other device to receive all or portions of the data that device 100 receives. In some situations, the drilling services provider can cause all or portions of the data to be transmitted to the other devices after device 100 receives the data. This can allow the provider to determine if the received data should or should not be transmitted to the other devices. Alternatively, the data can be received substantially simultaneously and substantially in real-time by the device 100 and all of the devices included in the network of other devices.

[0051] FIGS. 6A, B are flowcharts of an example process 600 for recommending drill bits for wellbores. The process 600 can be implemented by a computer system that includes data processing apparatus that can execute computer instructions stored on a computer-readable medium. For example, the process 600 can be executed by the mobile computing device 100. At 602, the process 600 begins and, at 604, the process receives incoming real time (RT) data (i.e., gamma ray log (GR), porosity, derivative log, and surface data). In some implementations, the incoming RT data can be uploaded to the mobile computing device 100 over the on-site network. At 608, a check to determine whether minimum data required for analysis has been obtained can be performed. If not (decision branch "NO"), then more data can be requested from the client (i.e., the server computer system 106, the computer-readable storage media 128, and the like) at 610. At 612, another check can be performed to determine whether minimum required data has been obtained. If not (decision branch "NO"), then additional data can be manually entered at 616 based on supplied information. If it is determined that minimum required data has been provided (decision branch "YES"), then, at 606, a depth interval for analysis can be received. Alternatively, or in addition, the depth interval for analysis can be obtained at 614. Using the received data, shale content determination can be performed at 618 and 620. Subsequently, at 622, porosity can be determined using either source log or Wyllie's Equation. At 624, mud weight and pore pressure values can be received, either automatically (from a computer system over the network) or manually (from a user of the mobile computing device 100). At 626, overbalance calculation can be performed and, at 628, rock strength calculation can be performed.

[0052] At 630, the rock strength can be output. For example, the mobile computing device 100 can display the rock strength in an output screen in the user interface 132. Alternatively, or in addition, the device 100 can transmit the rock strength over the one or more networks 108 to the server computer system 106. At 632, a rock strength (RS) input can be received. At 634, the log intervals can be stretched/compressed to accommodate geology of the proposed wellbore (for example, wellbore 110) or to update model to existing conditions, for example, arrivals of geological events at depths other than those of the original model, and the like. At 636, logged surface data and bit information can be received, for example, from the on-site computer systems. At 638, a historical wear rate of an offset wellbore (for example, wellbore 122) can be calculated. For example, a ratio of WOB/ROP (klb- ft/hr) of greater than 2 indicates that the drill bit is approaching high wear. The wear rate can be plotted against the historical wear rate of the offset wellbore. At 640, MSE can be calculated for the entire well. The MSE can be used as a stickslip or an additional wear indicator or as an indicator of drilling efficiency.

[0053] At 642, a check can be made to determine if the drilling interval was too slow or too short. If the drilling interval is neither too slow nor too short (decision branch "NO"), then it can be recommended that the same drilling conditions (for example, the drill bit and drilling parameters) be maintained at 650. If the drilling interval is not as expected (decision branch "YES"), then an expected run length, ROP, and rock strength based on the previously drilled wellbore (for example, wellbore 122) can be determined at 646. An adjustment in bit characteristics (for example, the cutter density, blade count, and the like) or drilling parameters can be recommended (for example, displayed in an output screen in a user interface and transmitted to the on-site computer systems) at 644. In this manner, multiple conditions at the wellbore 110 can be monitored, and solutions to changes to the drilling scenarios (for example, what-if conditions #1 - #n (648)) can be identified. Based on the changes to the drilling conditions, final bit recommendations can be provided at 652.

[0054] FIG. 7 is a flowchart of an example process 700 for providing the theoretical rate of penetration and the theoretical distance to be drilled ("drilling distance") for drilling a wellbore. The process 700 can be implemented by a computer system that includes data processing apparatus that can execute computer instructions stored on a computer-readable medium. For example, the process 700 can be executed by the mobile computing device 100. At 702 wellbore data including geological data that describes a wellbore and drill bit data describing the drill bit to drill a specified depth interval in the wellbore is received. At 704, overbalance and rock strength for the specified depth interval and mechanical specific energy (MSE) per unit volume of rock in the wellbore to be drilled to the specified depth interval can be determined using the wellbore data and the drill bit solution data. Under ideal conditions, the bit will perform with MSE at or below a specified value. At 706, a theoretical wear rate of the drill can be determined at least in part using the MSE. At 708, a historical wear rate of a drill bit used in an offset wellbore can be obtained. At 710, the historical wear rate can be compared with the theoretical wear rate. At 712, a theoretical rate of penetration and theoretical drilling distance for drilling the specified depth interval in the wellbore using the drill bit can be determined. At 714, input can be received from an external device. AT 716, in response to receiving the input, the theoretical rate of penetration and the theoretical drilling distance can be provided as output, for example, over a packet- switched data network. Providing this data as output can include transmitting this data to an external device over the network or displaying this data in a user interface of a mobile computing device (or both).

[0055] Implementations of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially-generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. A computer storage medium, for example, the computer-readable medium 106, can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially-generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical and/or non- transitory components or media (e.g., multiple CDs, disks, or other storage devices).

[0056] The operations described in this specification can be implemented as operations performed by a data processing apparatus, for example, data processing apparatus 102, on data stored on one or more computer-readable storage devices or received from other sources.

[0057] The term "data processing apparatus" encompasses all kinds of apparatus, devices, and machines for processing data, including by way of example, a programmable processor, a computer, a system on a chip, or multiple ones, or combinations, of the foregoing The apparatus can include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). The apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them. The apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures.

[0058] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

[0059] The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

[0060] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory, or both. The essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive, data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto -optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive), to name just a few. Devices suitable for storing computer program instructions and data include all forms of non- volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto -optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0061] To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with a user by sending documents to and receiving documents from a device that is used by the user; for example, by sending web pages to a web browser on a user's client device in response to requests received from the web browser.

[0062] Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network, for example, network 108. Examples of communication networks include a local area network ("LAN") and a wide area network ("WAN"), an inter-network (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks).

[0063] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. In some implementations, a server transmits data (e.g., an HTML page) to a client device (e.g., for purposes of displaying data to and receiving user input from a user interacting with the client device). Data generated at the client device (e.g., a result of the user interaction) can be received from the client device at the server. [0064] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any implementations or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0065] 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. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0066] Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous.

Claims

WHAT IS CLAIMED IS:

1. A computer-implemented method for selection of a drill bit solution for use in drilling a specified depth interval in a wellbore, said method comprising:

receiving, by a mobile computing device:

(a) a drill bit selection query comprising a specified depth interval to analyze,

(b) geological data for the selected depth interval ,

(c) drilling data for the specified depth interval comprising at least one of of proposed mud weight, proposed pore pressure and weight on bit, torque on bit, or RPM, and

(d) bit characteristics comprising at least one of proposed drill-ability index, specific energy rating, or wear rating;

determining, by the mobile computing device, lithology for the selected depth interval;

receiving, by the mobile computing device, a historical wear rate of another drill bit used in an offset well, said wear rate defined by degradation per interval foot;

determining, by the mobile computing device, a theoretical wear rate of a drill bit for use in drilling the specified depth interval;

comparing, by the mobile computing device, the theoretical wear rate of the drill bit and the historical wear rate of the other drill bit to determine if the theoretical wear rate is less than the historical wear rate of the other drill bit;

determining, by the mobile computing device, a theoretical rate of penetration (ROP) and a theoretical drilling distance using the drill bit; and

outputting, by the mobile computing device, data comprising the theoretical ROP and the theoretical drilling distance.

2. The method of claim 1, further comprising determining, by the mobile device: overbalance for the specified depth interval using the received drilling data for the specified depth interval; rock strength for the specified depth interval using the received geological data for the specified depth interval; and

mechanical specific energy (MSE) per unit volume of rock to be drilled in the specified depth interval using the received drilling data.

3. The method of claim 1 wherein determining the rock strength comprises:

determining upper and lower limits of gamma ray log; and

using the upper and lower limits to define 100% concentration values of shale and non-shale.

4. The method of claim 2, wherein the theoretical wear rate of the drill bit for use in drilling the specified depth interval is determined using at least the previously calculated MSE.

5. The method of claim 1, further comprising:

receiving a subsequent drill bit selection query that includes selection criteria that are different from criteria received in the drill bit selection query;

determining a new theoretical wear rate of a revised drill bit that satisfies the selection criteria for use in drilling the specified depth interval using the previously calculated MSE;

comparing the new theoretical wear rate of the revised drill bit and the historical wear rate of the drill bit used in an offset well to determine if the new theoretical wear rate is less that the historical wear rate ;

determining a new theoretical ROP and a new theoretical drilling distance in the wellbore for the revised drill bit; and

in response to receiving the subsequent drill bit selection query, outputting data comprising the new theoretical ROP and the new theoretical drilling distance.

6. The method of claim 5, wherein the data comprising the new theoretical ROP and the new theoretical drilling distance is output to another mobile computing device.

7. The method of claim 5, wherein the selection criteria comprises cutter density, blade count specific energy, drillability index, wear rate, blade profile, nozzle number and size, bit forces, steerability, face control and walk, gauge length, and cutter count.

8. The method of claims 1 or 5, further comprising displaying, by the mobile computing device, the output data in response to the received drill bit selection query.

9. The method of claim 1, wherein said wear rate is based at least in part on ROP-to- torque ratio data for the offset well.

10. The method of claim 9, further comprising determining said wear rate by one or more of:

an empirical calculation of a percentage of wear incurred by a bit in the offset well, based on dull condition included in a bit record; or

application of wear rate to proposed bit, with appropriate adjustments for bit characteristics and application of parameters weight on bit (WOB) and rotations per minute (RPM); or

interval length and changing formation type.

11. The method of claim 1 , wherein comparing the theoretical wear rate of the drill bit and the historical wear rate of the other drill bit comprises:

determining wear rate of the drill bit; and

plotting the determined wear rate over a wear rate curve of the drill bit from the offset well.

12. The method of claim 1 wherein the geological data is stored on a hardware storage device, and wherein receiving the geological data comprises reading the data from the hardware storage device.

13. The method of claim 1 , further comprising receiving the geological data over a data network either automatically or by interrogation.

14. The method of claim 13, wherein receiving the geological data over the data network automatically comprises:

detecting a connection to the data network; and

in response to detecting the connection to the data network, automatically triggering transmission of the geological data over the data network.

15. The method of claim 36, wherein receiving the geological data over the cellular network further comprises:

forming a connection with a server computer system that hosts a website; and triggering transmission of the geological data over the cellular network upon logging on to the website.

16. The method of claim 1 wherein receiving the geological data comprises reading the geological data upon determining that the mobile computing device is within a wireless network signal zone at a drilling site.

17. The method of claim 16, further comprising triggering an automatic download of the geological data upon determining that the mobile computing device is within the wireless network signal zone.

18. The method of claim 3, further comprising:

stretching or compressing log data between two given points in space for a nearby well to conform to a geological model generated for a proposed well; and

repeating the stretching or compressing until the entire interval of the proposed well is modeled.

19. The method of claims 3 and 18, further comprising determining porosity from user-selected log(s) according to Wyllie's Equation.

20. The method of any of claims 1 through 19 wherein receiving drilling data for the specified depth interval further comprises receiving a description of drill bit

characteristics for a plurality of drill bits.

21. The method of claims 1 through 19 wherein receiving drilling data for the specified depth interval further comprises receiving drilling fluid characteristics and rheology from the wellbore.

22. The method of claims 20 or 21 further comprising determining the MSE per unit volume of rock to be drilled in the specified depth interval using the description of drill bit characteristics or the drilling fluid characteristics and rheology.

23. The method of any of claims 1 to 22 further comprising:

accessing, by the mobile computing device, data stored in a computer system, the stored data including at least one drill bit selection that satisfies the drill bit query and associated rock strength, MSE and proposed performance criteria comprising theoretical wear rate, theoretical ROP and theoretical time drilling the specified depth interval in the proposed wellbore for the at least one bit;

receiving, by the computing device, actual drilling data for at least a portion of the specified interval that has been drilled in the wellbore;

comparing, by the computing device, the received actual data to the accessed stored data; and

outputting, by the computing device, differences between the actual data and the accessed stored data.

24. The method of claim 23, further comprising:

determining, by the computing device, adjustments to drilling conditions based on the differences between the actual data and the accessed stored data; and transmitting, by the computing devices, the adjustments.

25. The method of claim 24, wherein transmitting the adjustments comprises transmitting the adjustments to at least one of a driller, a computer system that operates the drill bit, or a bottom hole assembly that includes the drill bit.

26. The method of claim 25, wherein the adjustments include at least one of a change of a drilling condition or an instruction to remove the drill bit from the wellbore.

27. The method of claim 23, further comprising storing in the computer system, said at least one drill bit selection that satisfies the drill bit query and storing the associated rock strength, MSE and proposed performance criteria comprising theoretical wear rate, theoretical ROP and theoretical drilling distance in the proposed wellbore for the at least one bit.

28. The method of claim 23, wherein a difference includes a difference between 5 and 10 percent between the actual data and the accessed stored data.

29. The method of claim 23, wherein said actual drilling data received comprises at least one or more of WOB, RPM, flowrate, circulating mud pressure, and torque.

30. The method of claim 23, further comprising:

receiving, by the mobile computing device, a revised drill bit selection inquiry including a revised depth interval; and

determining, by the mobile computing device, a revised MSE per unit volume of rock to be drilled in the revised depth interval;

determining, by the mobile computing device, a revised theoretical wear rate of the revised drill bit for use in drilling the specified depth interval using the revised MSE; determining, by the mobile computing device, a revised theoretical ROP and revised theoretical drilling distance in the wellbore for the revised proposed bit;

outputting, by the mobile computing device, the revised theoretical ROP and revised theoretical drilling distance in the wellbore for the revised proposed bit.

31. The method of claim 1 or 23, wherein the mobile computing device comprises at least one of a smart phone, a tablet computer, a laptop computer, or a personal digital assistant.

32. The method of claims 1 or 23, wherein receiving the actual drilling data comprises downloading the actual drilling data via a communications protocol.

33. The method of claims 1 or 23, wherein receiving the actual drilling data comprises receiving the actual drilling data in real time.

34. The method of claim 1, wherein the geological data is received from instruments.

35. The method of claim 1, wherein the data is output over a data network.

36. The method of claim 1, wherein the data network is a cellular network, and wherein the method further comprises receiving the geological data over the cellular network.

37. A computer implemented method, the method comprising:

generating, by at least one computer, in response to a drill bit selection query, instructions to cause rendering of a graphical interface on a display, the graphical interface comprising at least one selectable control;

detecting a selection of the at least one selectable control;

in response to detecting the selection, determining:

rock strength for a depth interval using geological data for the specified depth interval, lit ho logy for the depth interval,

mechanical specific energy (MSE) per unit volume of rock to be drilled in the specified depth interval using drilling data,

a theoretical wear rate of a drill bit for use in drilling the specified depth interval using the (MSE); and

a theoretical ROP and theoretical drilling distance in the wellbore for the proposed bit, and

displaying, in the graphical interface, at least one drill bit solution for drilling the specified interval, the theoretical ROP and theoretical drilling distance in the wellbore.

38. The method of claim 37, further comprising:

receiving, in the graphical user interface, a revised drill bit selection inquiry; and receiving another selection of the at least one selectable control after receiving the revised drill bit selection query;

in response to receiving the other selection, determining:

a revised rock strength for the depth interval by the computing device using geological data for the specified depth interval,

a revised mechanical specific energy (MSE) per unit volume of rock to be drilled in the specified depth interval using drilling data,

a revised theoretical wear rate of the drill bit for use in drilling the specified depth interval using the previously calculated (MSE); and

a revised theoretical ROP and theoretical period of time drilling the specified depth interval in the wellbore for the proposed bit; and

displaying, in the graphical interface, at least one revised drill bit solution for drilling the specified interval, the revised theoretical ROP and the revised theoretical period of time drilling the specified depth interval in the wellbore for the revised proposed bit.

39. The method of claims 37 or 38, further comprising displaying, in the graphical user interface, one or more fields to receive at least one drill bit selection criteria, wherein the selection criteria includes at least one of a cutter density or a blade count.

40. The method of any one of claims 29 or 30, further comprising:

displaying, in the graphical user interface, a plurality of objects, each object representing an input option that corresponds to a respective drilling condition parameter; receiving, in the graphical user interface, a selection of a particular object of the plurality of objects, the particular object representing a particular input option; and

in response to receiving the selection of the particular object, displaying, in the graphical user interface, a control object representing a controller to control a particular drilling condition parameter to which the particular input option corresponds.

41. The method of any one of claims 29 or 30, further comprising:

displaying, in the graphical user interface, a plurality of objects, each object representing an output option that corresponds to a respective revised drill bit solution; receiving, in the graphical user interface, a selection of a particular object of the plurality of objects, the particular object representing a particular output option; and

in response to receiving the selection of the particular object, displaying, in the graphical user interface, an output object that includes the particular output option.

42. A computer-implemented method for selection of a drill bit for use in drilling a specified depth interval in a wellbore, said method comprising:

receiving, by a mobile computing device, wellbore data including geological data that describes a wellbore and drill bit data describing the drill bit to drill a specified depth interval in the wellbore;

determining, by the mobile computing device, lithology, overbalance, and rock strength for the specified depth interval, and mechanical specific energy (MSE) per unit volume of rock in the wellbore to be drilled to the specified depth interval using the wellbore data and the drill bit solution data; determining, by the mobile computing device, a theoretical wear rate of the drill bit at least in part using the MSE;

obtaining, by the mobile computing device, a historical wear rate of a drill bit used in an offset wellbore, the historical wear rate describing wear of a drill bit used to drill the offset wellbore;

determining, by the mobile computing device, a theoretical rate of penetration and theoretical drilling distance in the wellbore using the drill bit, wherein the theoretical rate of penetration and the theoretical drilling distance is determined, in part, by comparing the theoretical wear rate and the historical wear rate; and

in response to receiving input from an external device connected to the mobile computing device, providing the theoretical rate of penetration and the theoretical drilling distance.

43. The method of claim 42, wherein the drill bit data includes at least one or more of a cutter density, a blade count specific energy, a drillability index, a wear rate, a blade profile, a nozzle number and size, bit forces, steerability, face control and walk, a gauge length, and a cutter count.

44. The method of claim 42, wherein providing the theoretical rate of penetration and the theoretical drilling distance comprises transmitting the theoretical rate of penetration and the theoretical drilling distance in to the external device over a network.

45. The method of claim 44, wherein the network is a packet-switched data network.

46. The method of claim 42, wherein providing the theoretical rate of penetration and the theoretical drilling distance comprises displaying the theoretical rate of penetration and the theoretical drilling distance in a user interface connected to the mobile computing device.

47. The method of claim 42, wherein providing the theoretical rate of penetration and the theoretical drilling distance comprises:

detecting, by the mobile device, a connection to a data network; and

in response to detecting the connection, transmitting the theoretical rate of penetration and the theoretical drilling distance over the network.

48. The method of claim 47, further comprising receiving the input from the external device after detecting the connection.

49. The method of claim 47, wherein the wellbore data and the drill bit data is received by the mobile computing device over the network.

50. The method of claim 49, wherein the wellbore data and the drill bit data is received from a computer-readable storage device that stores the wellbore data and the drill bit data.