ADAPTIVE MULTISCALE NEAR-WELLBORE STRESS AND STABILITY ANALYSIS METHOD

Abstract

A computer-implemented method for determining near-wellbore stress and state in a drilled well includes: importing input data of a form of data files; calculating stress and pressure parameters along a wellbore path from the input data imported; displaying one or more of the input data and the calculated stress and pressure parameters along a well path of the drilled well; receiving, by a graphical user interface (GUI), a user selection of a depth at which distribution of the near-wellbore stress and state around a wellbore is determined; in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

Description

BACKGROUND

Accurate knowledge of stress and strain (i.e., deformation) around a borehole is of critical importance to drilling, completion, stimulation, and production of oil and gas wells in various geological formations, including sandstone, carbonate, and shale formations. The stress and deformation of the rock mass around a borehole may be affected by the in-situ stress, origin reservoir pore pressure and borehole pressure, and a geometrical orientation and a hole size. Further, stress and deformation variables around a borehole are typically dynamic rather than static and they evolve under a drive of fluid diffusion and fluid-mechanical coupling in time domain. In the exploration, construction, and production practice, it is very helpful to have the distributions of stresses, pore pressure, and design parameters at a full or partial borehole length scale. It is also desirable to have the detailed information of stresses, deformation, and damage regions around a borehole at various depths.

SUMMARY

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

According to one or more embodiments disclosed herein, a computer-implemented method for determining near-wellbore stress and state in a drilled well includes: importing input data of a form of data files; calculating stress and pressure parameters along a wellbore path from the input data imported; displaying one or more of the input data and the calculated stress and pressure parameters along a well path of the drilled well; receiving, by a graphical user interface (GUI), a user selection of a depth at which to determine distribution of the near-wellbore stress and state around the wellbore; in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

Further, according to one or more embodiments disclosed herein, a non-transitory computer-readable medium stores instructions which, when executed, cause a computer to perform operations including: importing input data of a form of data files; calculating stress and pressure parameters along a wellbore path from the input data imported; displaying one or more of the input data and the calculated stress and pressure parameters along a well path of a drilled well; receiving, by a graphical user interface (GUI), a user selection of a depth at which distribution of near-wellbore stress and state around a wellbore is determined; in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

Further, according to one or more embodiments disclosed herein, a device includes: at least one hardware processor; and a non-transitory computer-readable storage medium coupled to the at least one hardware processor and storing programming instructions for execution by the at least one hardware processor. The programming instructions, when executed, cause the at least one hardware processor to perform operations including: importing input data of a form of data files; calculating stress and pressure parameters along a wellbore path from the input data imported; displaying one or more of the input data and the calculated stress and pressure parameters along a well path of a drilled well; receiving, by a graphical user interface (GUI), a user selection of a depth at which distribution of near-wellbore stress and state around a wellbore is determined; in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

BRIEF DESCRIPTION OF DRAWINGS

The following is a description of the figures in the accompanying drawings. In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.

FIG. 1 shows a petroleum system in accordance with one or more embodiments.

FIG. 2 shows an architecture of a system that implements a method in accordance with one or more embodiments.

FIG. 3 shows a flowchart describing process steps that implements a method in accordance with one or more embodiments.

FIG. 4 shows an example of a graphical user interface (GUI) of the system in accordance with one or more embodiments.

FIG. 5 shows an example of external data in a tabular form in accordance with one or more embodiments.

FIGS. 6A and 6B show views when external data is imported to a system that implements a method in accordance with one or more embodiments.

FIG. 7 shows an example of a GUI of the system in accordance with one or more embodiments.

FIG. 8 shows an example of a pulldown menu in accordance with one or more embodiments.

FIG. 9 shows an example of a GUI of the system in accordance with one or more embodiments.

FIG. 10 shows an example of a GUI of the system in accordance with one or more embodiments.

FIG. 11 shows an example of a GUI of the system in accordance with one or more embodiments.

FIG. 12 shows an example of a pulldown menu in accordance with one or more embodiments.

FIGS. 13A-13F show various visualizations of results of local-scale computations in accordance with one or more embodiments.

FIG. 14 shows a computing device in accordance with one or more embodiments.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

In the following description of FIGS. 1-14, any component described with regard to a figure, in various embodiments disclosed herein, may be equivalent to one or more like-named components described with regard to any other figure. For brevity, descriptions of these components will not be repeated with regard to each figure. Thus, each and every embodiment of the components of each figure is incorporated by reference and assumed to be optionally present within every other figure having one or more like-named components. Additionally, in accordance with various embodiments disclosed herein, any description of the components of a figure is to be interpreted as an optional embodiment which may be implemented in addition to, in conjunction with, or in place of the embodiments described with regard to a corresponding like-named component in any other figure.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a passive soil gas sample system” includes reference to one or more of such systems.

Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

It is to be understood that one or more of the steps shown in the flowcharts may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope disclosed herein should not be considered limited to the specific arrangement of steps shown in the flowcharts.

Although multiple dependent claims are not introduced, it would be apparent to one of ordinary skill that the subject matter of the dependent claims of one or more embodiments may be combined with other dependent claims.

Embodiments disclosed herein relate to a novel method for computing, visualizing, and recording stress, pore pressure, and a mechanical state for an arbitrarily oriented borehole at both local (i.e., at a specific depth) and global (i.e., along part or all of a well path) scales. The computation and visualization at local and global scales can transit naturally. Files output from various mechanical earth models or other pre-processing tools at different format conventions can be inputted to a system that implements this method. To provide a smooth connection with those third-party tools/products, an adaptive mapping algorithm is implemented in this system such that the format convention of chosen preprocessing tools/products will be recorded in a dynamic database in the background after one-time manual mapping.

FIG. 1 shows a petroleum system (100) in accordance with one or more embodiments. The petroleum system (100) includes a source rock formation (104), or rocks in which hydrocarbons have been generated or are capable of hydrocarbon generation. A source rock formation (104) is one of the necessary elements of a petroleum system (100) and includes organic-rich sediments that may be deposited in a variety of environments. With hydrocarbons present in a source rock formation (104), a petroleum system (100) requires a migration of these hydrocarbons into a reservoir formation (114). The hydrocarbons may migrate vertically through faults (118) or fractures upwards into a hydrocarbon reservoir (114). The fault (118) depicted in FIG. 1 fractures and displaces the source rock formation (104), allowing for the escape of the hydrocarbons in these cases. Hydrocarbon migration may also occur as a near-vertical migration from the reservoir (114) due to a buoyancy-driven flow of hydrocarbons. A buoyancy-driven flow of hydrocarbons occurs when the upward buoyancy force of the hydrocarbons is greater than the downward force of gravity, causing an upward migration. Migration may be local, as shown in the petroleum system (100) of FIG. 1 or may occur over distances of hundreds of kilometers in larger sedimentary basins and is a crucial mechanism to the formation of a viable petroleum system (100).

The reservoir (114) contains an accumulation of hydrocarbons including oil and/or natural gas. The reservoir (114) is usually a permeable and porous rock layer capable of storing and transmitting hydrocarbon fluids. Reservoirs (114) are formed under temperature conditions that may preserve the hydrocarbons and are overlain by an impermeable layer or layers of rock, known as a hydrocarbon seal (112). The hydrocarbon seal (112) acts as a barrier to stop the further migration of hydrocarbons and may be accompanied with an appropriate topographic structure, such as an anticline which helps to further trap the accumulation of hydrocarbons within the reservoir (114).

A hydrocarbon exploration may be conducted on a prospective petroleum system (100) by drilling into the suspected reservoir (114) in order to detect, quantify, or extract the hydrocarbons. A wellbore (102) may be drilled by a drill bit (126) attached by a drill pipe (106) to a drill rig (116) located on the Earth's surface (108). The wellbore (102) may traverse a plurality of overburden layers (110) and one or more seal formations (112) to a prospective hydrocarbon reservoir (114)

The logging system (120) may include the tools to determine a well log, including tools from a wireline logging or a logging while drilling (LWD) operation. A logging tool may be lowered into the wellbore (102) to acquire measurements as the tool traverses a depth interval. The plot of the logging measurements versus depth may be referred to as a “log” or “well log”. Well logs may provide depth measurements of the wellbore (102) that describe such reservoir characteristics as formation porosity, formation permeability, resistivity, water saturation, and the like. The resulting logging measurements may be stored or processed or both, for example, by a control system (122), to generate corresponding well logs for the wellbore (102).

FIG. 2 shows an architecture of a computing system (200) that implements a method in accordance with one or more embodiments, and FIG. 3 shows a flowchart describing process steps that implement the method. The four key components of the system architecture are shown in FIG. 2. FIG. 2 shows that the computing system (200) includes an adaptive mapping module (210), a global computation and visualization module (220), a depth selection module (230), and a local computation and visualization module (240), each of which is described below with reference to FIG. 3, in further detail.

After the process begins at step 310, the adaptive mapping module (210) loads external data (250) from outside sources and adjusts the format of the external data (250) into the format of global data (260) at step 320. The external data (250) include geometrical information at various depths of a well path, stresses of the rock (geological) formation and pore pressures at the depths, and rock properties at the depths. The external data may be obtained by the logging system (120) described above and/or as outputs from mechanical earth models (MEMs). A MEM carries measurements and mechanical properties of rocks and fractures and models responses of rocks and fractures to various loads, stresses, pressures, and temperatures acting on the formations at different times and depths. The external data (250) may be given in a tabular format such as a CSV (comma separated value) file. Data obtained by the logging system (120) and/or output data from different MEMs may have different orders, number formats, and names of data columns. When a specific data file is selected as a source of the external data (250), columns of the specific data file need to be mapped to a format the computing system (200) adopts and the data stored in the specific data file is loaded into the computing system (200). Accordingly, the adaptive mapping module (210) may include a CSV file selection submodule (212), a column mapping submodule (214), a data loading submodule (216), and a database (218), as shown in FIG. 2. Further details of actions of the adaptive mapping module (210) will be described later.

The data imported in the step 320 becomes part or a whole of global data (260) used in the global computation and visualization module (220). In one or more embodiments, the global computation and visualization module (220) includes a global computation submodule (222) and a profile plot submodule (224), as shown in FIG. 2. At step 330, the global computation submodule (222) calculates additional global data from the imported data when the imported data do not include data that a user would like to examine. The calculated additional global data becomes part of the global data (260) and may be used in the following steps together with the imported data.

The profile plot submodule (224) generates profile plots of the global data (260) at step 340. The profile plots of the global data (260) show variations of various parameters along the well path.

Further details of actions of the global computation and visualization module (220) are described below.

At step 350, a depth selection module (230) is used to select an arbitrary depth on the well path and extract data at the arbitrary depth from the global data (260). Further details of actions of the depth selection module (230) will be described later.

Extracted portion of the global data (260) by selecting an arbitrary depth on the well path at step 350 becomes part of local data (270) in a local computation and visualization module (240). The local computation and visualization module (240) includes a local computation submodule (242) and various chart submodules such as a curve chart submodule (244) and a polar chart submodule (246), as shown in FIG. 2. At step 360, the local computation submodule (242) calculates additional local data from the extracted portion of the global data (260) when the extracted portion of the global data (260) do not include data that a user would like to examine. The calculated additional local data becomes part of the local data (270) and may be used in the following steps together with the global data (260).

The local data (270) that include the extracted portion of the global data (260) and calculated additional local data may be displayed in various plots at step 370. The various plots may include curve charts generated by the curve chart submodule (244) and polar plots generated by the polar chart submodule (246).

Further details of actions of the local computation and visualization module (240) are described below.

After various plots are generated to display local data (270) at an arbitrary depth on the well path, the process terminates at step 380.

Actions the modules and submodules perform at the steps are now described in reference to FIGS. 4-13F.

FIG. 4 shows an example of a graphical user interface (GUI) (400) of the system in accordance with one or more embodiments. The GUI (400) includes an operational bar (410). The operational bar (410) includes one or more operational icons, including for example the “Run” icon (412). Each of the operational icons represents a different function. Examples of the functions include “New Analysis,” “Open,” “Save,” “Save As . . . ,” “Run,” “Settings,” “Help,” and “Lock.” Each icon, if clicked or otherwise selected, can trigger the system to execute the corresponding function.

The GUI (400) includes an analysis (child) window (420). The analysis window (420) includes a control pane (422), a data spreadsheet (424), and a curve plot pane (426). FIG. 4 shows an initial state of the GUI (400) when no external data has been imported from external sources. Therefore, the control pane (422), the data spreadsheet (424), and the curve plot pane (426) do not contain any data and are shown empty.

Near-wellbore stress and stability analysis requires data of three categories: geometrical characteristics of a borehole; confining in-situ stresses and pore pressure; and rock properties. The geometrical characteristics include the radius (or diameter) of the borehole, the true vertical depth (TVD) of the wellbore, the inclination of the wellbore, and the azimuth of the wellbore. The confining in-situ stresses and pore pressure include pore pressure (PP), the vertical stress (Sv), the maximum horizontal stress (SH), the minimum horizontal stress (Sh), and the azimuth of the maximum horizontal stress. The rock properties include elastic/plastic properties and hydraulic properties (e.g., permeability and porosity). More specifically, the rock properties include Young's modulus, Poisson's ratio, the cohesive strength, the frictional angle, and the tensile strength. The hydraulic properties may be required for investigation of evolution of stress/stability parameters, rock properties, and wellbore states in time-domain caused by fluid diffusion.

FIG. 5 shows an example of external data (250) in a tabular form in accordance with one or more embodiments. The external data (250) shown in FIG. 5 may be stored in a form of a CSV data file to be imported to the computing system (200). As shown in FIG. 5, this exemplary data consists of 15 columns in total: the measured depth (MD) of the wellbore in the unit of foot, the radius of the borehole in the unit of foot, the TVD of the wellbore in the unit of foot, the inclination of the wellbore in the unit of degree, the azimuth of the wellbore in the unit of degree, the pore pressure gradient in the unit of ppg (pound per gallon), the vertical stress gradient in the unit of ppg, the maximum horizontal stress gradient in the unit of ppg, the minimum horizontal stress gradient in the unit of ppg, the azimuth of the SH in the unit of degree, Young's modulus in the unit of Mpsi (million pound per square inch), Poisson's ratio (no unit), the cohesive strength in the unit of psig (pound per square inch gauge), the friction angle in the unit of degree, and the tensile strength in the unit of psig. The first five columns from the MD of the well bore to the azimuth of the wellbore describe the geometries of the well path. The next five columns from the pore pressure gradient to the azimuth of the maximum horizontal stress describe the stresses and PP of the wellbore. The last five columns from Young's modulus to the tensile strength describe mechanical properties of the formation. Each column has its labeling name (“MD,” “Radius,” “TVD,” “Inclination,” “Azimuth,” “PP,” “SV,” “SH,” “Sh,” “AziSH,” “Ymod,” “Prat,” “Cohesion,” “Friction,” “Tension”) given by a MEM program in the first (top) row (510). The units of these values are shown in the second row (520). The, the values start from the third row.

When the external data (250) in the tabular form as shown in FIG. 5 are imported into the computing system (200), the column information of the external data (250) need to be mapped properly into the form of the global data (260). FIG. 6A shows a view (600) of import of external data (250) while the column information is specified. The view (600) includes an information pane (610) and a raw data preview pane (620). The raw data preview pane (620) shows the external data (250). The information pane (610) lists the labeling names of the columns of the external data (250) in the column titled “CSV Column” (612), their designations in the global data (260) in the computing system (200) in the column titled “Associated Parameter” (614), and their units in the global data (260) in the computing system (200) in the column titled “Unit” (616). The entries of the first column “CSV Column” (612) are copied from the first row (510) of the external data (250). The entries of the second column “Associated Parameter” (614) and third column “Unit” (616) are selected from predetermined candidates using pulldown menus exemplified by a pulldown menu (630) shown in FIG. 6A. As shown in FIG. 6A, names of some columns (e.g., “MD” in column 1 and “TVD” in column 3) used in the external data (250) are the same as the designations used in the computing system (200). On the other hand, some other columns (e.g., “PP” in column 6, “SV” in column 7, and “SH” in column 8) in the external data (250) are different from the designations in the computing system (200) and require manual mapping. As shown in FIG. 6B, “PP” is mapped to “Pore Pressure Gradient,” “SV” to “Overburden Stress Gradient,” and “SH” to “Maximum Horizontal Stress Gradient.” The unit of each imported column is also chosen manually. The columns that are not mapped will not be assigned and not be imported (i.e., skipped). Further, as shown in FIG. 6B, rows that contain specified NULL values input (and shown right next to “NULL value” (634) in the information pane (610)) may be skipped by checking a box next to the text “Ignore rows containing NULL values” (632). After all the columns that need to be imported are manually mapped as shown in FIG. 6B, a user can click the “Import” button (640) to load the external data (250) to the computing system (200).

After manual mapping operation of the columns in the external data (250) to the columns in the data used in the computing system (200) (as the global data (260)), the column mapping relations may be stored in the database (218) in the adaptive mapping module (210) in the background. A user may use the same MEM in his/her work and the system may use an adaptive mapping algorithm with the same columns using their names as identifiers to the data structures of the system. Then, the stored column mapping relations may be loaded from the database (218) and reused when a user import a different external data (250) but from the same MEM. Further, the system may store in the database (218) more than one sets of column mapping relations and a user may select one set from the stored sets. This feature allows a user to stick to his/her own name conventions of all variables used in the MEMs and he/she needs to manually map/store his/her name conventions and column mapping relations only once.

Once the external data (250) are imported into the computing system (200), the global data (260) are not empty and the control pane (422) shows a list of datasets and their units in a “Dataset” column (722) and a “Unit” column (724), respectively, as shown in FIG. 7. The “Dataset” column (722) shows the names of the datasets stored as the global data (260). The “Unit” column (724) shows the units of the datasets. For example, for the true vertical depth (TVD), the unit is “ft” (feet) among candidates of, for example, “ft” (feet), “m” (meters), and “cm” (centimeters).

Further, the control pane (422) enables control of visualization of the data spreadsheet (424) and the curve plot pane (426). Specifically, the list of the control pane (422) includes a “Table” column (726) and a “Plot” column (728). The “Table” column (726) and the “Plot” column (728) are populated with checkboxes corresponding to the datasets. When the checkboxes in the “Table” column (726) are checked, the corresponding datasets are shown in the data spreadsheet (424). When the checkboxes in the “Plot” column (728) are checked, the corresponding datasets are plotted along the well path in the curve plot pane (426). In the example shown in FIG. 7, all the checkboxes in the “Table” column (726) are checked and all the datasets are displayed in the data spreadsheet (424). Further, only the checkboxes of “PP” and “Sh” in the “Plot” column (728) are checked and those datasets, PP and Sh, are plotted in the curve plot pane (426).

In addition to displaying the global data in the data spreadsheet (424) and the curve plot pane (426), the global computation and visualization module (220) of the computing system (200) enables computation and visualization of variables derived from the external data (250) imported by the adaptive mapping module (210). Examples of the variables derived from the external data (250) are borehole collapse mud pressure and borehole fracturing mud pressure. Further, a safe mud pressure window defined by the borehole collapse mud pressure as the lower bound and the borehole fracturing mud pressure as the upper bound can be obtained and plotted.

More specifically, clicking the ‘Run’ icon (412) on the toolbar opens a pulldown menu (800) that lists available options of global-scale computation and visualization functionalities, as shown in FIG. 8. In the example shown in FIG. 8, the pulldown menu (800) lists “Collapse Mud Weights” (810) and “Fracturing Mud Weights” (820). When the “Collapse Mud Weights” (810) is clicked, the global computation submodule (222) calculates the borehole collapse mud pressure. When the “Fracturing Mud Weights” (820) is clicked, the global computation submodule (222) calculates the borehole fracturing mud pressure.

FIG. 9 shows the GUI shown in FIG. 7 but after the variable, “Collapse MW” (borehole collapse mud pressure) and “Frac MW” (borehole fracturing mud pressure), are calculated. After the computation, the newly derived variables are added to the global data (260) and listed in the control pane (422) and their own checkboxes in the “Table” column (922) and the “Plot” column (924). The checkboxes of the “Collapse MW” and “Frac MW” in the “Table” column (922) are checked in the control pane (422) and calculated values of the derived variables are displayed in the data spreadsheet (424) under “Collapse MW” (932) and “Frac MW” (934), respectively. Further, the checkboxes of the “Collapse MW” and “Frac MW” in the “Plot” column (928) are checked in the control pane (422) and calculated values of the derived variable are plotted in the curve plot pane (426).

In one or more embodiments, transition from the global scale (i.e., along the well path) borehole computation and visualization to the local scale (i.e., at a selected depth) borehole computation and visualization may be implemented in the data spreadsheet (424). Clicking any one row in the data spreadsheet (424) opens a pulldown “Launch Single-Depth Analysis” menu (428), as shown in FIG. 10. Further clicking the “Launch Single-Depth Analysis” menu (428) selects a specific depth corresponding the row in the well path and the local data (270) is extracted from the global data (260). In this example shown in FIG. 10, the row that displays variable values at the MD of 9,046.0988 feet is selected. Therefore, by clicking the “Launch Single-Depth Analysis” menu (428), the data at the MD of 9,046.0988 feet is extracted as the local data (270) and local computation and visualization at this depth of MD of 9,046.0988 feet will be performed.

Transition to the local scale borehole computation and visualization further creates an analysis tab (1130) that includes an input tab (1140). The input tab (1140) displays the local data (270) extracted from the global data (260) and other values and conditions that the local computation and visualization module (240) uses to perform local computation and visualization. The input tab is a child tab of the analysis tab such that if a user closes the analysis tab (1130) by clicking its X mark, the input tab (1140) also disappears. However, if a user closes the input tab (1140) by clicking its X mark, the analysis tab (1130) remains open (as shown on the screen). As shown in FIG. 11, the local data extracted at the MD of 9,046.0988 are displayed in “Wellbore Geometry” box (1160), “Elastic Properties” box (1170), “In-Situ Stress State” box (1180), and “Failure Criteria & Strength Properties” box (1190). “Analysis Type” box (1150) shows default selections of “Elastic (no time involved)” for “Wellbore Stability Model” (1152) and “Impermeable” for “Borehole Condition” (1154). The “Failure Criteria & Strength Properties” box (1190) shows a default selection of “Mohr-Coulomb” for “Failure Criterion” (1192). The box (1190) also shows a radial ratio. In a cylindrical coordinate system, the reference point is the center of the cylinder. Any point around the borehole can be located by its radial distance (from the borehole center) and wellbore angle (measured from the maximum confining stress). The radial ratio is the ratio of the radial distance to the borehole radius. In other words, the radial ratio is still the radial distance of a point normalized by a constant (borehole radius).

In the local scale analysis, clicking the “Run” icon on the toolbar opens a pulldown menu (1200) that lists available options of local-scale computation and visualization functionalities, as shown in FIG. 12. In the example of FIG. 12, available options are “Stress Curves” option (1202), “Stress Color Maps” option (1204), “Failure Potential Curves” option (1206), “Failure Regions” option (1208), “Mud Weight Windows” option (1210), and “Polar Charts” option (1212). More details of the options will be described next.

The “Stress Curves” option (1202) and the “Stress Color Maps” option (1204) trigger the local computation submodule (242) to calculate each of six stress components (Srr, Stt, Szz, Srt, Stz, Srz) of the stress tensor and the pore pressure at the selected depth. When the local computation submodule (242) completes calculation, the curve chart submodule (244) and/or the polar chart submodule (246) create any one of the calculated variables (Srr, Stt, Szz, Srt, Stz, Srz, and the pore pressure) to visualize in a curve plot form or a color contour form. The curve plot may be presented in a circumferential direction or a radial direction. For example, FIG. 13A shows a conferential distribution of the tangential stress (Stt) on the wellbore wall as a function of the borehole angle and FIG. 13B displays a color contour map of the radial stress (Srr). The inner circle in FIG. 13B corresponds to the borehole (i.e., the radial coordinates is less than the radius of the borehole).

The “Failure Potential Curves” option (1206) triggers the local computation submodule (242) to calculate the risk of the wellbore running into failures at the selected depth under various mud weights. The risk is evaluated based on a selection of the failure criterion specified in the “Failure Criteria & Strength Properties” box (1190). When the local computation submodule (242) completes calculation, the curve chart submodule (244) creates a failure potential curve, as shown in FIG. 13C.

The “Failure Regions” option (1208) triggers the local computation submodule (242) to calculate failure regions under a given wellbore pressure, which is specified as “Mud Weight” in “In-Site Stress State” box (1180). When the local computation submodule (242) completes calculation, the polar chart submodule (246) creates a polar plot that shows the failure regions around the wellbore at the selected depth for a mud weight of 8 ppg, as shown in FIG. 13D.

Even with the same confining stresses, pore pressure, and rock (formation), the stability of the wellbore at the same depth may vary with the inclination angle and azimuth of the wellbore. The “Mud Weight Windows” option (1210) triggers the local computation submodule (242) to calculate the mud weight required for maintaining the wellbore stability under different azimuth and inclination angles. When the local computation submodule (242) completes calculation, the curve chart submodule (244) creates a curve chart that shows the safe mud weight window for wellbores with the wellbore inclination angle shown in the abscissa and varying from 0 degree (vertical well) to 90 degrees (horizontal well), as shown in FIG. 13E. The safe mud weight window is defined by two lines. The lower line corresponds to the collapse mud pressure line below which the wellbore will fail in compressive shearing and the upper line is the fracturing mud weight line above which the wellbore will fail in fracturing.

The “Polar Charts” option (1212) triggers the local computation submodule (242) to calculate the borehole collapse mud pressure. When the local computation submodule (242) completes calculation, the polar chart submodule (246) creates a polar plot that indicates the critical collapse mud weight for the complete ranges of wellbore's azimuth and inclination angles. In other words, the lower line in FIG. 13E corresponds to data on a full circumference of a circle of one radius in FIG. 13F.

FIG. 14 depicts a block diagram of a computer system (1400) used to provide computational functionalities associated with described algorithms, methods, functions, processes, flows, and procedures as described in this disclosure, according to one or more embodiments. The illustrated computer (1402) is intended to encompass any computing device such as a server, desktop computer, laptop/notebook computer, wireless data port, smart phone, personal data assistant (PDA), tablet computing device, one or more processors within these devices, or any other suitable processing device, including both physical or virtual instances (or both) of the computing device. Additionally, the computer (1402) may include a computer that includes an input device, such as a keypad, keyboard, touch screen, or other device that can accept user information, and an output device that conveys information associated with the operation of the computer (1402), including digital data, visual, or audio information (or a combination of information), or a GUI.

The computer (1402) can serve in a role as a client, network component, a server, a database or other persistency, or any other component (or a combination of roles) of a computer system for performing the subject matter described in the instant disclosure. The illustrated computer (1402) is communicably coupled with a network (1430). In some implementations, one or more components of the computer (1402) may be configured to operate within environments, including cloud-computing-based, local, global, or other environment (or a combination of environments).

At a high level, the computer (1402) is an electronic computing device operable to receive, transmit, process, store, or manage data and information associated with the described subject matter. According to some implementations, the computer (1402) may also include or be communicably coupled with an application server, e-mail server, web server, caching server, streaming data server, business intelligence (BI) server, or other server (or a combination of servers).

The computer (1402) can receive requests over network (1430) from a client application (for example, executing on another computer (1402) and responding to the received requests by processing the said requests in an appropriate software application. In addition, requests may also be sent to the computer (1402) from internal users (for example, from a command console or by other appropriate access method), external or third-parties, other automated applications, as well as any other appropriate entities, individuals, systems, or computers.

Each of the components of the computer (1402) can communicate using a system bus (1403). In some implementations, any or all of the components of the computer (1402), both hardware or software (or a combination of hardware and software), may interface with each other or the interface (1404) (or a combination of both) over the system bus (1403) using an application programming interface (API) (1412) or a service layer (1413) (or a combination of the API (1412) and service layer (1413). The API (1412) may include specifications for routines, data structures, and object classes. The API (1412) may be either computer-language independent or dependent and refer to a complete interface, a single function, or even a set of APIs. The service layer (1413) provides software services to the computer (1402) or other components (whether or not illustrated) that are communicably coupled to the computer (1402). The functionality of the computer (1402) may be accessible for all service consumers using this service layer. Software services, such as those provided by the service layer (1413), provide reusable, defined business functionalities through a defined interface. For example, the interface may be software written in JAVA, C++, or other suitable language providing data in extensible markup language (XML) format or another suitable format. While illustrated as an integrated component of the computer (1402), alternative implementations may illustrate the API (1412) or the service layer (1413) as stand-alone components in relation to other components of the computer (1402) or other components (whether or not illustrated) that are communicably coupled to the computer (1402). Moreover, any or all parts of the API (1412) or the service layer (1413) may be implemented as child or sub-modules of another software module, enterprise application, or hardware module without departing from the scope of this disclosure.

The computer (1402) includes an interface (1404). Although illustrated as a single interface (1404) in FIG. 14, two or more interfaces (1404) may be used according to particular needs, desires, or particular implementations of the computer (1402). The interface (1404) is used by the computer (1402) for communicating with other systems in a distributed environment that are connected to the network (1430). Generally, the interface (1404) includes logic encoded in software or hardware (or a combination of software and hardware) and operable to communicate with the network (1430). More specifically, the interface (1404) may include software supporting one or more communication protocols associated with communications such that the network (1430) or interface's hardware is operable to communicate physical signals within and outside of the illustrated computer (1402).

The computer (1402) includes at least one computer processor (1405). Although illustrated as a single computer processor (1405) in FIG. 14, two or more processors may be used according to particular needs, desires, or particular implementations of the computer (1402). Generally, the computer processor (1405) executes instructions and manipulates data to perform the operations of the computer (1402) and any algorithms, methods, functions, processes, flows, and procedures as described in the instant disclosure.

The computer (1402) also includes a memory (1406) that holds data for the computer (1402) or other components (or a combination of both) that can be connected to the network (1430). For example, memory (1406) can be a database storing data consistent with this disclosure. Although illustrated as a single memory (1406) in FIG. 14, two or more memories may be used according to particular needs, desires, or particular implementations of the computer (1402) and the described functionality. While memory (1406) is illustrated as an integral component of the computer (1402), in alternative implementations, memory (1406) can be external to the computer (1402).

The application (1407) is an algorithmic software engine providing functionality according to particular needs, desires, or particular implementations of the computer (1402), particularly with respect to functionality described in this disclosure. For example, application (1407) can serve as one or more components, modules, applications, etc. Further, although illustrated as a single application (1407), the application (1407) may be implemented as multiple applications (1407) on the computer (1402). In addition, although illustrated as integral to the computer (1402), in alternative implementations, the application (1407) can be external to the computer (1402).

There may be any number of computers (1402) associated with, or external to, a computer system containing computer (1402), wherein each computer (1402) communicates over network (1430). Further, the term “client,” “user,” and other appropriate terminology may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, this disclosure contemplates that many users may use one computer (1402), or that one user may use multiple computers (1402).

Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible, including dimensions, in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

1. A computer-implemented method for determining near-wellbore stress and state in a drilled well, comprising:

importing input data of a form of data files;

calculating stress and pressure parameters along a wellbore path from the input data imported;

displaying one or more of the input data and the calculated stress and pressure parameters along a well path of the drilled well;

receiving, by a graphical user interface (GUI), a user selection of a depth at which to determine distribution of the near-wellbore stress and state around a wellbore;

in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and

displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

2. The method according to claim 1, wherein the input data comprises one or more of:

measured properties of a geological formation around the drilled well; and

properties of the geological formation around the drilled well that are obtained from mechanical earth models.

3. The method according to claim 1, wherein the input data comprises one or more of:

stresses in a geological formation around the drilled well;

pore pressures in the drilled well;

elastic properties of the geological formation around the drilled well;

plastic properties of the geological formation around the drilled well;

permeability of the geological formation around the drilled well; and

porosity of the geological formation around the drilled well.

4. The method according to claim 1, wherein

the input data comprises data values along the well path, and

the form of data files is a tabular format.

5. The method according to claim 1, wherein the stress and pressure parameters calculated comprises one or more of:

maximum and minimum horizontal stresses and orientations around a borehole;

borehole collapse pressure; and

borehole fracturing pressure.

6. The method according to claim 1, wherein the near-wellbore parameters calculated comprise one or more of:

stress tensor in a geological formation around the drilled well;

failure potential curve around the drilled well;

failure region around the drilled well; and

safe mud weight window.

7. A non-transitory computer-readable medium storing instructions which, when executed, cause a computer to perform operations comprising:

importing input data of a form of data files;

calculating stress and pressure parameters along a wellbore path from the input data imported;

displaying one or more of the input data and the calculated stress and pressure parameters along a well path of a drilled well;

receiving, by a graphical user interface (GUI), a user selection of a depth at which distribution of near-wellbore stress and state around a wellbore is determined;

in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and

displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

8. The non-transitory computer-readable medium according to claim 7, wherein the input data comprises one or more of:

measured properties of a geological formation around the drilled well; and

properties of the geological formation around the drilled well that are obtained from mechanical earth models.

9. The non-transitory computer-readable medium according to claim 7, wherein the input data comprises one or more of:

stresses in a geological formation around the drilled well;

pore pressures in the drilled well;

elastic properties of the geological formation around the drilled well;

plastic properties of the geological formation around the drilled well;

permeability of the geological formation around the drilled well; and

porosity of the geological formation around the drilled well.

10. The non-transitory computer-readable medium according to claim 7, wherein

the input data comprises data values along the well path, and

the form of data files is a tabular format.

11. The non-transitory computer-readable medium according to claim 7, wherein the stress and pressure parameters calculated comprises one or more of:

maximum and minimum horizontal stresses and orientations around a borehole;

borehole collapse pressure; and

borehole fracturing pressure.

12. The non-transitory computer-readable medium according to claim 7, wherein the near-wellbore parameters calculated comprise one or more of:

stress tensor in a geological formation around the drilled well;

failure potential curve around the drilled well;

failure region around the drilled well; and

safe mud weight window.

13. A device, comprising:

at least one hardware processor; and

a non-transitory computer-readable storage medium coupled to the at least one hardware processor and storing programming instructions for execution by the at least one hardware processor, wherein

the programming instructions, when executed, cause the at least one hardware processor to perform operations comprising: importing input data of a form of data files; calculating stress and pressure parameters along a wellbore path from the input data imported; displaying one or more of the input data and the calculated stress and pressure parameters along a well path of a drilled well; receiving, by a graphical user interface (GUI), a user selection of a depth at which distribution of near-wellbore stress and state around a wellbore is determined; in response to receiving the user selection, calculating near-wellbore parameters describing the near-wellbore stress and state around the wellbore; and displaying, by the GUI, the calculated near-wellbore parameters around the wellbore.

14. The device according to claim 13, wherein the input data comprises one or more of:

measured properties of a geological formation around the drilled well; and

properties of the geological formation around the drilled well that are obtained from mechanical earth models.

15. The device according to claim 13, wherein the input data comprises one or more of:

stresses in a geological formation around the drilled well;

pore pressures in the drilled well;

elastic properties of the geological formation around the drilled well;

plastic properties of the geological formation around the drilled well;

permeability of the geological formation around the drilled well; and

porosity of the geological formation around the drilled well.

16. The device according to claim 13, wherein

the input data comprises data values along the well path, and

the form of data files is a tabular format.

17. The device according to claim 13, wherein the stress and pressure parameters calculated comprises one or more of:

maximum and minimum horizontal stresses and orientations around a borehole;

borehole collapse pressure; and

borehole fracturing pressure.

18. The device according to claim 13, wherein the near-wellbore parameters calculated comprise one or more of:

stress tensor in a geological formation around the drilled well;

failure potential curve around the drilled well;

failure region around the drilled well; and

safe mud weight window.