Patent Application
20140077963
Common practice in pressure management services is to constantly monitor the annular pressure or its pressure gradient equivalent (ECD) at the pressure sensor position and check if the value is in the allowed pressure window. A single downhole tool is normally used to measure the annular pressure and to calculate the ECD with the true vertical depth of the tool. Thus modeling is required, in order to fill the sensor gaps.
Modern digital systems are able to calculate parameters based on physical or empirical models in intervals, in which measured sensors values are not available. Both, time and location sensor gaps can be bridged with modern digital technologies. Whereas the visualization of the modeled values is done based on the individual application, it is difficult to put them into the context of allowed operational ranges for a whole interval. If alarms need to be generated, usually a small number of points of interests (POI) from the interval is selected and put into the context of minimum and maximum allowed critical or warning values. The direct comparison of the actual value and the min/max ranges is usually visualized with traffic light colors.
A method of processing parameter data includes: receiving at least one alarm value for a selected interval, the at least one alarm value generated based on a comparison of estimated parameter values at one or more respective interval points with limits at the respective interval points; performing, by a processor, a statistical analysis of the at least one alarm value over the selected interval; and generating an alarm indication associated with the selected interval, the alarm indication corresponding to a result of the statistical analysis.
A computer program product is stored on machine readable media for processing parameter data by executing machine implemented instructions. The instructions are for: receiving at least one alarm value for a selected interval, the at least one alarm value generated based on a comparison of estimated parameter values at one or more respective interval points with limits at the respective interval points; performing, by a processor, a statistical analysis of the at least one alarm value over the selected interval; and generating an alarm indication associated with the selected interval, the alarm indication corresponding to a result of the statistical analysis.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
There are provided systems and methods for generating alert or alarm indications in conjunction with downhole parameters. A data visualization and alarm method utilizes measured or modeled values in a selected interval (e.g., depth or time interval) for comparison with alarm data, such as discrete data points and/or alarm data curves, and displays the measured or modeled data in the context of one or more alarm levels (e.g., on a display screen or printed report). This allows visualizing a high resolution alarm history for every single point in an interval. The alarms can be accumulated and statistically analyzed for specified depth intervals to generate accumulated alarms, which can be used to display various kinds of information for each interval. In one embodiment, the alarm displays can be visually compacted, which allows alarm data to be shown using less space, and also allows alarm data to be shown in context with other information. The systems and methods described herein also allow for control of the level of detail that is viewed by zooming between lower resolution and high resolution displays.
In one embodiment, relatively high resolution alarm data is accumulated on a depth scale and/or time scale, by statistically analyzing alarm data over a selected interval and generating an alarm indication for that interval. Severity levels can be attached to each selected depth or time location or interval, and displayed so that times or locations at which a parameter is out of an acceptable range can be readily identified.
Referring to
In one embodiment, the system 10 includes a derrick 16 mounted on a derrick floor 18 that supports a rotary table 20 that is rotated by a prime mover at a desired rotational speed. The drill string 12 includes one or more drill pipe sections 22 or coiled tubing, and is connected to a drill bit 24 that may be rotated via the drill string 12 or using a downhole mud motor. Drilling fluid or drilling mud is pumped through the drill string 12 and/or the wellbore 14. The system 10 may also include a bottomhole assembly (BHA) 26.
During drilling operations a suitable drilling fluid 24 from, e.g., a mud pit 28 is circulated under pressure through the drill string 12 by one or more mud pumps 30. The drilling fluid 24 passes into the drill string 12 and is discharged at a wellbore bottom through the drill bit 22, and returns to the surface by advancing uphole through an annular space between the drill string 12 and the borehole wall and through a return line 32.
Various sensors and/or downhole tools may be disposed at the surface and/or in the borehole 12 to measure parameters of components of the system 10 and or downhole parameters. Such parameters include, for example, parameters of the drilling fluid 24 (e.g., flow rate and pressure), environmental parameters such as downhole temperature and pressure, operating parameters such as rotational rate, weight-on-bit (WOB) and rate of penetration (ROP), and component parameters such as stress, strain and tool condition. For example, a downhole tool 34 is incorporated into the drill string 12 and includes sensors for measuring downhole fluid flow and/or pressure in the drill string 12 and/or in the annular space to measure return fluid flow and/or pressure. Additional sensors 36 may be located at selected locations, such as an injection fluid line and/or the return line 32. Such sensors may be used, for example, to regulate fluid flow during drilling operations.
The sensors and downhole tool configurations are not limited to those described herein. The sensors and/or downhole tool 34 may be configured to provide data regarding measurements, communication with surface or downhole processors, as well as control functions. Such sensors can be deployed before, during or after drilling, e.g., via wireline, measurement-while-drilling (“MWD”) or logging-while-drilling (“LWD”) components. Exemplary parameters that could be measured or monitored include resistivity, density, porosity, permeability, acoustic properties, nuclear-magnetic resonance properties, formation pressures, properties or characteristics of the fluids downhole and other desired properties of the formation surrounding the borehole 14. The system 10 may further include a variety of other sensors and devices for determining one or more properties of the BHA (such as vibration, bending moment, acceleration, oscillations, whirl, stick-slip, etc.) and drilling operating parameters, such as weight-on-bit, fluid flow rate, pressure, temperature, rate of penetration, azimuth, tool face, drill bit rotation, etc.)
In one embodiment, the downhole tool 34, the BHA 26 and/or the sensors 36 are in communication with a surface processing unit 38. In one embodiment, the surface processing unit 38 is configured as a surface drilling control unit which controls various production and/or drilling parameters such as rotary speed, weight-on-bit, fluid flow parameters, pumping parameters. The surface processing unit 38 may be configured to receive and process data, such as measurement data and modeling data, as well as display received and processed data. Any of various transmission media and connections, such as wired connections, fiber optic connections, wireless connections and mud pulse telemetry may be utilized to facilitate communication between system components.
The downhole tool 34, BHA 26 and/or the surface processing unit 38 may include components as necessary to provide for storing and/or processing data collected from various sensors therein. Exemplary components include, without limitation, at least one processor, storage, memory, input devices, output devices and the like.
In one embodiment, the surface processing unit 38, in conjunction with downhole and/or surface processors and sensors, is configured to operate as part of a drilling and/or pressure management system. For example, in drilling operations utilizing underbalanced, overbalanced or managed pressure drilling techniques, or other techniques that utilize drilling fluid pressure measurement and/or management, the surface processing unit 38 is configured as a processing and control unit that controls drilling parameters, such as pump speed and mud density, based on measurements of the drilling fluid flow and/or pressure in the borehole.
In one embodiment, the surface processing unit 38 (or other suitable processor) is configured to analyze measured or modeled downhole parameters and generate alarms or alerts in response to such parameters approaching or coinciding with selected limits. For example, minimum and maximum annular pressure or flow parameters for returning fluid are set based on formation parameters such as pore pressure and fracture pressure. The minimum value is either defined by the pore pressure gradient or the collapse gradient (whichever is higher at a certain depth). The maximum value is defined by the formation fracture gradient. Usually the minimum and maximum values are defined before the drilling activities start, but they can also be redefined while drilling or automatically set without human interaction. Depending on the well, the values may be either single values for the whole planned depth range of the well or curves with varying values for each depth. The minimum and maximum values define a pressure window within which annular fluid pressure should be maintained in order to maintain the integrity of the borehole during drilling and prior to deploying casing strings.
Parameters like mud density, mud rheology and flow rate, ROP are set as part of the drilling planning, so that the planned drilling pressure fits into the pressure window for the whole drilled section. When the section is actually drilled, the measured pressure from a downhole tool is available and can be compared against the pressure window values at sensor depth. Automatic alarms are generated to indicate whether the annular pressure at sensor depth is outside the pressure window.
In addition, hydraulic modeling systems allow calculating a parameter profile from top to the bottom of the wellbore and can provide pressure values along the full well path. The modeling system can use available measurements (e.g. downhole pressure, pump pressure) for calibration purposes. In a fully automated real-time system the modeled pressure profile along the well path is constantly updated. Such modeled parameter data can be periodically or continuously compared to the pressure window curves for alarm generation. For example, an initial model of the wellbore prior to drilling can be analyzed in conjunction with the pressure window curves to generate alarms or alarm indications at relevant points along the borehole path. As measurements performed during drilling are received (e.g., in real-time or near real-time), the alarm indications can be updated to provide updated information to drillers regarding possible problems. Measured and modeled parameter values are collectively referred to herein as “estimated values” or “estimated parameters.”
In the first stage 61, parameter limits, i.e., parameter values that define an upper and/or lower limit of acceptable parameters, are established. For example, drilling parameters are selected to plan for a drilling operation, which may include calculation of the pore pressure, the collapse gradient and/or the fracture gradient along the planned wellbore path. These values may be acquired via any suitable method. For example, seismic velocity data may be used to predict pore pressure and gradient values.
In one example, upper and/or lower return fluid parameter limits are set for a plurality of points along a selected interval, such as a depth or time interval representing part or all of a borehole or planned borehole. One or more of these parameters are combined to generate upper and lower pressure limits, in order to set the lower and upper limits of a pressure window. Each limit is associated with a depth or time location or a depth or time interval. The generated limit points may be processed to produce and display one or more limit curves along the interval.
In the second stage 62, alert or alarm values for the selected parameters are selected relative to the parameter limits. The alarm values may be values associated with discrete depth/time interval levels, or may be processed to generate curves. Alarm values and/or alarm curves are generated based on a selected relation to the parameter limits, and may be displayed with the limit values. In the example shown in
Additional display components may also be included. For example, a window center curve 78 provides an orientation about the ideal distance from lower and upper limits. In another example, if the limits for one or more depth ranges cannot be set or can just be set for either the lower or the upper limit, this can be indicated, e.g., by a “blind zone” indication 80.
Alarms are selected and configured to be generated in response to actual or predicted pressure parameters (e.g., return fluid pressure) intersecting the limit curve or alert curves. As described herein, an “alarm” is any indication (visual or otherwise) that is associated with a specific time or depth (or time or depth interval), which indicates that one or more estimated values at the time/depth or interval exceed an acceptable value. For example, a red visual alarm such as that shown in
In the third stage 63, a drill string, logging string and/or production string is disposed within the wellbore 12 and a downhole operation is performed. During the operation, parameters such as fluid pressure, temperature or drilling parameters are estimated via sensor devices (e.g., the sensors 36 and/or the downhole tool 34). In one embodiment, instead of performing an actual operation, an operation can be fully or partially modeled, and parameters can be estimated based on the model.
For example, drilling hydraulic modeling systems can calculate a parameter profile, e.g.,an equivalent circulating density (ECD) profile, from the top of the wellbore down to the bottom, an example of which is shown as profile curve 82 in
In the fourth stage 64, the estimated parameter value data is compared to the limit values and/or the alarm values to generate alarms where appropriate. For each depth/time at which estimated parameter data is compared to alarm data, an alarm may be generated that indicates the level of risk of the parameter exceeding the set limits. The estimated value is associated with a depth (or time) and compared to the associated limit or alarm data. For example, intersection of the estimated value with an alarm curve results in an alarm indication being generated and displayed for the depth associated with the estimated value. For those depths at which an alarm is not generated, no indication need be provided. At other depths, a yellow (warning) or red (critical) indication shows where the operation parameters came close to the operating limits (e.g., pore pressure or fracture pressure). In some embodiments, a different color coding can be used to differentiate upper and lower limits. Additional intermediate colors may be used to generate a continuous or near-continuous color coding scheme.
For example, as shown in
In the fifth stage 65, generated alarms are analyzed over a selected interval or intervals. The alarm data is statistically analyzed over each selected interval and an alarm value or indication (referred to herein as an “accumulated alarm”) is generated based on the statistical analysis. For example,
Any suitable statistical analysis can be used to generate accumulated alarm indications for selected intervals. Examples of statistical analysis include calculation of a summation, an average, a variance, a standard deviation, t-distribution, a confidence interval, and others. Examples of data fitting include various regression methods, such as linear regression, least squares, segmented regression, hierarchal linear modeling, and others.
In the example of
The depth scale alarm display 84 therefore displays not only whether an alarm was triggered over an interval, but also provides additional information, such as the number of alarms, the type of alarm and the relation between that alarm and previous conditions. The alarm and visualization method described in this stage requires only warning and critical limits, in addition to estimated values as input.
This visualization and alarm method provides a way to utilize all modeled values in an interval for alarm generation and to put them into the context of individual alarm levels.
In the sixth stage 66, operational parameters may be modified as needed, based on alert indications and/or alarms, in order to keep them within the selected parameter limits.
Referring to
Various depth ranges might not contain any displayed alarm. For example, the data shown in
In one embodiment, the alarm data can be displayed with other information, which allows one to view the alarm data in the context of various other downhole parameters or conditions. For example, as shown in
The methods 100 and 110 are described in the context of exemplary alarm displays shown in
Referring to
For example, referring to
At stage 115, a statistical analysis of the alarms within each accumulated interval is performed to generate an accumulated alarm for that interval. In the example of
At stage 116, the accumulated alarm is set for each accumulated interval. At stage 117, the resulting alarms are added to the buffer.
As an illustration,
These accumulated alarms (“alarms of alarms”) can condense information and allow for visually compacting the full resolution alarm data. This compaction can allow for zooming features, whereby a user can zoom out to view a lower resolution but broader display or zoom in to view higher resolution details.
Instead of setting one fixed limit (e.g. 20%) as the single criteria, more intermediate linear or non-linear limits (e.g., between 0% and 100%) can be used, in order to provide more details (e.g. five limits at 10%, 20%, 50%, 70% and 90%). These limits can be extended until a continuous color scheme with multiple colors can be applied for visualization.
As shown in the above example, accumulated alarms may be compacted to a single value for each accumulated interval, which at least considers the length of intervals with critical alarms, warnings and the duration of alarms. In other embodiments, a combination of color and dot size may be used in order to visualize the single accumulated alarm. This will provide information about the alarm level and the duration at the same time. An exemplary alarm color and size scheme is shown in
In addition or in place of accumulating alarms along the depth axis for a specific time, the detailed alarm data can also be accumulated along the time axis for a specific depth. This allows assigning severity levels to each depth based on the overall duration of alarms at a specific depth. These intervals may be statistically analyzed, e.g., summed up or averaged, to provide accumulated durations for warning and critical events. For example,
In one embodiment, the display can be divided into multiple displays showing different kinds of events. For example,
In addition to alarms indicating depth/time duration of alarms, alarms can be set based on actual parameter measurements. For example, especially in wellbore stability and pressure management, not only the duration of alarm events is important, but also single very high or very low pressure peaks can have an impact on the stability of the formation. A third peak alarm level outside the critical alarm range (shown in
Generally, some of the teachings herein are reduced to an algorithm that is stored on machine-readable media. The algorithm is implemented by a computer or processor such as the surface processing unit 38 and provides operators with desired output. For example, data may be transmitted in real time from the tool 34 or sensors 36 to the surface processing unit 38 for processing.
The systems and methods described herein provide various advantages over prior art techniques. The systems and methods described herein facilitate control over downhole parameters and monitoring of downhole intervals having depth locations for which direct measurement data is unavailable. The embodiments described herein allow for periodic or continuous monitoring of depth intervals based on array type data.
In support of the teachings herein, various analyses and/or analytical components may be used, including digital and/or analog systems. The system may have components such as a processor, storage media, memory, input, output, communications link (wired, wireless, pulsed mud, optical or other), user interfaces, software programs, signal processors (digital or analog) and other such components (such as resistors, capacitors, inductors and others) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user or other such personnel, in addition to the functions described in this disclosure.
One skilled in the art will recognize that the various components or technologies may provide certain necessary or beneficial functionality or features. Accordingly, these functions and features as may be needed in support of the appended claims and variations thereof, are recognized as being inherently included as a part of the teachings herein and a part of the invention disclosed.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
