CA2516872C - Digital core workflow method using digital core images - Google Patents

Abstract

A method for registration and correction of downhole core depth information using digital core images. Digital core images are employed during depth registration, with top and base depths for a selected interval being determined by field data and a digital ruler which calculates an actual interval length based on the digital core image. Correction of the top and base depths is enabled by side- by-side display of the digital core image interval and corresponding well logging data, which displayed information can be manipulated by a user to provide more accurate depth information. The method further allows for shale volume calculations and facies interpretation, again employing the digital core images.

Description

DIGITAL CORE WORKFLOW METHOD USING DIGITAL CORE
IMAGES
FIELD OF THE INVENTION
The present invention relates to methods for determining formation depths, and more particularly to core logging methods.
BACKGROUND OF THE INVENTION
Although relatively expensive, coring - the taking of subsurface rock samples with specialized drilling tools - is one of the oldest methods of subsurface formation evaluation and the only method (other than cuttings analysis) for providing rock samples for laboratory analysis. Coring is used to provide geologists and other earth scientists with physical rock samples that can provide much-needed information on a direct rather than indirect basis.
A core bit is used to cut a generally cylindrical section of rock that is contained within a coring tube, which section within the tube is then brought to surface (any expected portion of the core that does not make it back to surface is considered to be "lost core"). The core tube is marked with a well name, core number, and subsurface interval depths and orientation (which end of the core was originally up-hole) by workers on the drilling rig. The marked core tubes, which may need to be frozen in the field (especially oil sands cores), are transported to a core handling lab where cores (with tube) are cut or "stabbed" along the tube length into two halves (see step 20 of Figure 2, which Figure summarizes the traditional physical core workflow), one side for viewing and the other side for cutting physical samples. The stabbed two halves are placed in two separate sets of boxes for future handling, with the viewing side being cleaned first before it is placed into core boxes. Core boxes of the two separate sets are labelled in a certain way to preserve the field information of the cores, including the well name, core number and orientation. Additional information (e.g. physical core box number) is added to the box label. If the cores are frozen, the sample side of the core will be sent back to a freezer to preserve the original state, and the viewing side of the core will be displayed in a room to be dried at step 21, normally at room temperature and typically for 24 to 48 hours.
Various tests and analyses can then be conducted on the cores in a laboratory setting. Traditionally, after the viewing side of the cores are dried to a certain degree, geologists use the physical core to engage in "core logging" at step which includes determining core depths and core order in the subsurface and describing the cores. Geologists also need to provide guidelines for lab technicians to select, or select by themselves, sample intervals (at step 23) and then do physical samplings (at step 27) with digital image shooting (at step 24) and image annotation (at step 25) in between.
Geologists need to determine exactly where (at what depths) the rock samples were taken from in order to understand geology deep in the Earth and to assess the spatial occurrence of mineral resources. As depth analysis is part of core logging, core depth correction has also been routinely performed by geologists for many years. During drilling, core depths are recorded by workers on a drilling rig, but very often they are not accurate (off-depth), and the geologist is faced with the task of attempting to determine depth information based on rock that has already been brought to surface.
The task of depth determination has been aided considerably by the development and use of special tools (well logging tools) which measure physical rock properties around the borehole. These rock properties include rock gamma radiation, resistivity, and porosity, among many others. Logging tools are sent downhole and take measurements at even spacing along the borehole. All the measurements for a given rock property, when plotted out against depth, will produce a rock property curve (or well log). Any given well will normally have a suite of well logs, and the depths on well logs are believed to be generally accurate if good logging procedures have been followed during well logging. As can be seen, rock samples and well logs provide different kinds of information from virtually the same object (rock), an analogy being the human body and its X-ray image. As a result, it is expected that a suite of well logs will match the physical cores in a certain way, which is the basis of core depth correction with well logging data as the depth reference.
Depth correction is used to shift initial core depths to match the depths determined by well logging data (including well logs and borehole imaging logs), as the latter is considered to provide accurate depth information. In a traditional physical core workflow, geologists bring a paper copy of the relevant well logs to the lab and lay them out on a table side-by-side with the core boxes, along with a copy of the field core depth sheet. They will then locate a depth reference marker on the well logs and its corresponding depth marker on the cores, assigning the depth of the depth reference marker to the corresponding core marker. Based on core length from the core depth reference marker and the depth of the marker itself, geologists then calculate depths of any points on the cores above and below the marker. They repeat this process until all the cores are depth-shifted or depth-corrected and have a good depth match with the well logs. A corrected core depth table, which normally includes top and base depths of each core box (and lost core intervals if any exist), is produced and provided to the lab for calculating sample depths. They may need to adjust lost core intervals (add or delete) and amend core orders to achieve a good match between the cores and the well logs. A mismatch between cores and well logs is normally caused by (1 ) core depths (including lost core intervals) being incorrectly recorded in the fields, (2) core expansion, (3) core being upside-down, (4) core being misplaced, or (5) any combination of these four. Depth correction alone normally takes 3 to 4 hours for a typical oil sands well.

Following core depth correction, geologists engage in core description by looking at physical cores (including visually estimating volume of shale), observing and describing the cores and recording a description on paper or in a computer file.
Core description will normally take 4 to 8 hours per oil sands well. Core depth correction and description are normally performed by one geologist.
After the cores are described, the geologist will provide sampling guidelines to enable a lab technician to select the sample intervals (or mark sample intervals by themselves). A lab technician will select sample intervals on the viewing portion of the cores, mark the sample intervals on the core boxes, and then calculate the sample depths based on the corrected core depth table provided by the geologist. The lab technician will also need to determine the physical position on the core for every meter depth, and these positions are marked on the core boxes for later use. Determination of sample depths and meter depth are traditionally achieved by using measurements of physical core lengths to enable calculation based on core top/base depths in the corrected core depth table. Sample selection/marking, sample depth calculation and determination/marking of position for each meter depth normally takes 2 to 4 hours per oil sands well. The marked sample intervals will usually then be translated to the sampling portion of the cores by another lab technician to guide physical sampling.
The viewing side of the core, which has been described by the geologist and marked with sample intervals, is then transported to a digital lab for digital imaging at step 24. Before digital images of the cores can be taken, the photographer needs to manually place many labels onto the physical cores, normally with magnetic stickers. There are three key label types (in addition to others): (1 ) top and base depths of cores; (2) sample intervals and sample numbers; and (3) meter depths. The manual, hard-coded labelling is a very time-consuming process and prone to errors; it also makes any updating of labels extremely difficult, especially when the geologist changes a depth. Changes in the geologist's core depths normally require re-calculating of meter depths/sample depths, which also requires "laying out" of the physical cores again and probably re-shooting the digital images. Labelling and digital imaging typically take 3 to 4 hours per oil sands well. Any label updating or re-shooting will add extra time to this process. This process produces raw digital images with labels.
Raw digital images with labels need to be cropped, and other information such as well name, depth scale, and company logo will be added to produce ready-for-print images at step 25 or 26. This process normally takes less than one hour per oil sands well. Ready-for-print digital core images will then be printed on high-quality photographic paper to produce core photographs or on paper at step 26. A paper copy is generally used by the lab technician to translate sample intervals that are marked on view-side cores and recorded on the digital images to the sample-side cores to enable physical sampling. The core photograph hard copies are normally not printed out on photographic paper until the passage of to 4 weeks, to avoid any potential waste should any update on image annotation be needed.
As is abundantly clear from the foregoing, there are numerous disadvantages to the traditional physical core workflow:
1 ) Several people are necessarily involved. More than eight people (one geologist and more than seven lab technicians) are usually involved, from core stabbing to producing deliverable results for oil companies. The more people that are involved, the harder it is to co-ordinate and the more opportunities there are for mistakes. There are more inherent errors as well.
2) The traditional workflow is time-consuming (as can be seen in Figure 2). It typically takes 24 to 48 hours to dry oil sands cores. Seventeen to twenty two hours elapses from core logging (core depth correction and description) to producing ready-for-print digital images and getting ready for physical sampling, and another 1 to 4 weeks will usually pass while waiting for the core photographs.
3) The reliance on a physical core workflow. Most processes are happening on physical cores. People involved therefore need to be physically present in a lab, working on the physical cores. The workflow also accordingly requires usage of physical lab space.
4) Geologists do the depth correction and core togging with physical paper-copy well logs and physical cores. In order for them to do core depth correction, geologists need to visually estimate the depth of a depth marker on well logs, and then manually translate that depth to the corresponding core depth marker, to physically measure the core length at a given point from a core marker with a measuring tape (and then to calculate the corrected depth of the given point). They need to repeat the above process for every point for which they need to calculate a corrected core depth. The process is slow and prone to errors; in addition, any change in the depth of a depth marker requires repetition of the above steps.
5) The use of manual, hard-coded labelling. All sample intervals, core depth and meter depth labels, plus all other labels are manually placed on the physical cores before any digital images are taken. The labelling process is time-consuming and prone to errors, and the resultant labelling (now part of the images) is hard-coded and makes it extremely difficult to make any required updates and changes.

6) Due to the time-consuming nature of the traditional workflow, sample selection and sample depth calculation are normally carried out by a lab technician with sampling guidelines provided by a geologist. As a result, sample selection is not totally controlled by the geologist, and very often more samples are taken than is needed.
What is needed, therefore, is an improved and more efficient workflow that overcomes the above disadvantages of the traditional physical workflow.
SUMMARY OF THE INVENTION
The present invention accordingly seeks to provide a method for utilising digital core images in depth registration and correction processes.
The present invention further seeks to provide a digital, integrated workflow comprising a method for utilising digital core images in core depth registration, core depth correction, sample selection, digital image annotation, shale volume quantification, facies interpretation and core description.
According to a first aspect of the present invention there is provided a method for registration of downhole core depth information comprising the steps of:
a. providing at least one digital image of a core sample from a well;
b. displaying the at least one digital image on a display device;
c. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;
d. establishing an approximate actual depth value for the first depth of the displayed interval; and e. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval.
According to a second aspect of the present invention there is provided a method for registration and correction of downhole core depth information comprising the steps of:
a. providing at least one digital image of a core sample from a well;
b. providing well logging data corresponding to the core sample;
c. displaying the at least one digital image on a display device;
d. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;
e. establishing an approximate actual depth value for the first depth of the displayed interval;
f. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval;
g. displaying the well logging data adjacent the displayed interval;
h. allowing for comparison of the well logging data and the displayed interval; and i. allowing for correction of the first depth and the second depth.
According to a third aspect of the present invention there is provided a method for on-line registration and correction of downhole core depth information comprising the steps of:
_g_ a. providing a web portal for accessing digital images and well logging data and a server for storing the digital images and the well logging data;
b. allowing for uploading of at least one digital image of a core sample from a well to the server;
c. allowing for uploading of well logging data from the well to the server;
d. downloading and displaying the at least one digital image on a display device;
e. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;
f. establishing an approximate actual depth value for the first depth of the displayed interval;
g. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval;
h. downloading and displaying the well logging data adjacent the displayed interval;
i. allowing for comparison of the well logging data and the displayed interval; and j. allowing for correction of the first depth and the second depth.
According to a fourth aspect of the present invention, there is provided a method for determining shale volume in a core sample from a well comprising the steps of:
a. selecting at least one region of a digital image of the core sample to represent a shale type;
b. specifying colour threshold values for the shale type;
c. specifying shale volume calculation options; and d. calculating a shale volume value.
Preferably, a plurality of shale volume values are calculated, each at a discrete shale volume depth point, enabling plotting of a shale volume curve which can be displayed on a display device. This fourth aspect can be combined with the methods of the first, second and third aspects of the present invention.
According to a fifth aspect of the present invention, there is provided a method for enabling facies interpretation of a core sample from a well comprising the steps of:
a. displaying a digital image of the core sample on a display device;
b. defining at least one facies by means of characteristics including facies colour and minimum and maximum shale volume value cut-offs, the facies colour and minimum and maximum shale volume value cut-offs being determined by reference to the digital image of the core sample;
c. selecting a facies interval directly from the digital image by selecting first and second locations representing top and base depths of the facies interval;
d. identifying the at least one facies with at least a part of the facies interval based on the characteristics;

e. displaying the at least one facies on the display device according to the top and base depths; and f. allowing for inspection and interpretation of the displayed at least one facies.
This fifth aspect can be combined with the methods of the first, second, third and fourth aspects of the present invention.
According to a sixth aspect of the present invention, there is provided a computer readable memory having recorded thereon statements and instructions for execution by a computer to carry out the method of any one of the other aspects of the present invention.
According to a seventh aspect of the present invention, there is provided a digital core workflow method comprising the steps of:
a. providing at least one digital image of a core sample from a well;
b. providing well logging data corresponding to the core sample;
c. displaying the at least one digital image on a display device;
d. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;
e. establishing an approximate actual depth value for the first depth of the displayed interval;
f. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval;

g. displaying the well logging data adjacent to the displayed interval;
h. allowing for comparison of the well logging data and the displayed interval to enable selecting corresponding depth markers on the displayed interval and the displayed well logging data, and to enable adjusting lost core intervals;
i. allowing for correction of the first depth and the second depth;
j. selecting at least one region of the at least one digital image of the core sample to represent a shale type;
k. specifying colour threshold values for the shale type;
I. specifying shale volume calculation options;
m. calculating a shale volume value;
n. defining at least one facies by means of characteristics including facies colour and minimum and maximum shale volume value cut-offs, the facies colour and minimum and maximum shale volume value cut-offs being determined by reference to the at least one digital image;
o. selecting a facies interval directly from the at least one digital image by selecting first and second locations representing top and base depths of the facies interval;
p. identifying the at least one facies with at least a part of the facies interval based on the characteristics;
q. displaying the at least one facies on the display device according to the top and base depths;

r. allowing for inspection and interpretation of the displayed at least one facies; and s. using corrected top and base depths to annotate the at least one digital image.
In exemplary embodiments of the present invention, the providing of the well logging data and the at least one digital image of a core sample from a well is achieved by obtaining the well logging data and the at least one digital image from an oil company. The display device is preferably a computer monitor receiving signals from a user computer workstation.
The displayed interval is preferably selected by means of: positioning a mouse cursor over a first location on the displayed at least one digital image representing the first depth; clicking a mouse button to select the first location;
positioning the mouse cursor over a second location on the displayed at least one digital image representing the second depth; and clicking the mouse button to select the second location. The first depth may represent either the top depth of the displayed interval (with the second depth then representing the bottom depth of the displayed interval) or the bottom depth (the second depth then representing the top depth). The approximate actual depth value for the first depth is preferably established based on field data, as explained below, and the length of the displayed interval is preferably measured by means of a predetermined digital ruler that equates pixel numbers with a set length value.
After depth registration is accomplished, comparison and correction processes can be conducted. Preferably, the step of allowing for comparison of the well logging data and the displayed interval is achieved by means of displaying the well logging data and the displayed interval in parallel, adjacent orientation, enabling a user to visually inspect the well logging data and the displayed interval for correlation purposes. Allowing for correction of the first and second depths is then preferably achieved by means of: allowing a user to pick corresponding markers on the well logging data and the displayed interval, by means of mouse cursor positioning and location selection; inserting correlation lines connecting the corresponding markers; inspecting the digital interval to determine if there are any lost core intervals; adding any desired sub-intervals to the displayed interval to represent lost core intervals; and axially shifting the displayed interval such that the correlation lines are generally horizontal. Preferred embodiment of the present invention comprise the further step of using corrected top and base depths to annotate the at least one digital image.
The use of digital core images during depth registration, rather than reliance on the presence of physical core samples, provides tremendous advantages for geologists and the companies they work for, particularly when this is linked to the use of the Internet for access and dissemination of information. While digital images have been used in the past to summarize core logging information, and occasionally for comparison against well logging data during depth correction processes, the advantage of using digital core images in depth registration is a novel development in the field.
A method according to the present invention requires fewer personnel, with time expenditure reduced substantially when compared with traditional methods. All information, including well logs and cores, is provided in digital form and can therefore be easily manipulated, analyzed, and distributed to others. The geologist need no longer be confined to a laboratory setting to engage in core logging, but can instead be at some remote location anywhere in the world at a computer workstation.
Further, geologists engaged in traditional workflow can only do depth correction one box at a time, without having ready access to the whole picture of the entire well. The present invention, by contrast, can display both well logs and core images for the entire well on one screen by changing depth scale, and depth correction can be performed at the same time for the entire well. The methods of the present invention allow a user to attempt different correlation and matching scenarios before proceeding to the depth correction stage, and a user can easily insert or delete lost core or adjust core order.
In the end, the present invention can produce highly accurate depth determinations, integrating depth registration/correction with sample picking, image annotation, VSH (shale volume) calculation and picking facies intervals directly from digital core images, streamlining the entire core workflow.
A detailed description of an exemplary embodiment of the present invention is given in the following. It is to be understood, however, that the invention is not to be construed as limited to this embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:
Figure 1 is a schematic illustration of a digital core workflow according to the present invention;
Figure 2 is a schematic illustration of a traditional physical core workflow;
Figure 3 is a schematic illustration of a system for executing a method according to the present invention;
Figure 4 is a schematic illustration of the modules and information flow of the present invention;
Figure 5 is a flowchart illustrating a method according to the present invention;
Figure 6 is a representation of a login window;

Figure 7 is a representation of a project name entry window;
Figure 8 is a representation of a well name entry window;
Figure 9 is a flowchart illustrating the depth registration process;
Figure 10 is a screen shot of a digital ruler definition window;
Figure 11 is a representation of a raw digital core image with core number and box number as the only labels;
Figure 12 is a screen shot of a Smart DepthsT"" window illustrating how various depth registration information is displayed on an annotated core image;
Figure 13 is a screen shot of a well log loading window;
Figure 14 is a flowchart illustrating the depth correction process;
Figure 15 is a schematic illustration of the adjacent display of well logging data and stacked core images during the marker-picking portion of the depth correction process;
Figure 16 is a schematic illustration of the adjacent display of well logging data and stacked core images during the fine-tuning portion of the depth correction process;
Figure 17 is a screen shot of the display during the fine-tuning portion of the depth correction process;
Figure 18 is a lost core deletion window;
Figure 19 is a lost core insertion window;
Figure 20 is a screen shot illustrating uncorrected and corrected depths on a display;

Figure 21 is a raw digital image with annotations;
Figure 22 is a raw digital image provided with a frame and associated information;
Figure 23 is a digital core image with full annotation and frame information;
Figure 24 is a screen shot of a digital core image after selection of two sample intervals;
Figure 25 is a sample registration window;
Figure 26 is a representation of a sand/shale calibration window for shale volume calculations;
Figure 27 is a shale volume calculation options window;
Figure 28 is a screen shot of one embodiment of a display in the Depth Correction Window;
Figure 29 is a screen shot of a facies definition window; and Figure 30 is a flowchart illustrating the facies interpretation process.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. The preferred embodiment of the present invention will be described below by reference to an overall digital core workflow, which digital core workflow comprises a method and system referred to as ADFMT"~ (an acronym for "Accurate Depths for Facies and Modeling").
Digital Core Workflow Referring now in detail to Figure 1, a digital core workflow is illustrated in accordance with the present invention. As can be seen, after cores (which may be frozen) are stabbed into two halves at step 1, the view-side cores are placed at step 2a into a specialized drying room 2b for approximately 10 to 14 hours to dry the cores, instead of simply displaying the cores in an ordinary core-view room. The specialized drying room 2b is tightly sealed after the doors are closed and is separated from other ordinary view rooms or office rooms. The temperature in the room is settable, and is normally higher than room temperature. The humidity is settable, as well, through dehumidifiers, at a level normally much lower than typical office conditions. The room 2b is also provided with good internal circulation. The composite effect of the above three conditions is that the cores can be dried much faster, reducing drying time from 24 to 48 hours down to 10 to 14 hours for typical oil sands cores.
Dried cores are then transported to a digital imaging studio for digital imaging at step 3. This workflow order is very different from the traditional physical core workflow in which this step 3 happens near the end of the workflow process (see step 24 in Figure 2). This change in workflow order allows for a prompt acquisition of the digital format data of the cores, to enable the depth registration process (described below) to begin. Only the core number and physical box number are required to be placed onto the physical cores for labelling, since any other labels can be added digitally with the ADFM system at step 4. This simplified labelling requirement can reduce digital core image shooting time from 3 to 4 hours per oil sands well to less than one hour.
All processes at step 4 take place digitally in the ADFM system, and the view-side cores can be sent at step 6 to a core storage facility. The ADFM system, described in detail below, is a computer-assisted system that enables the use of digital core images in the core logging work that is normally done by geologists and some of the work traditionally done by lab technicians. As will be clear from the following description, this integrated digital ADFM system overcomes the disadvantages of the traditional physical workflow described above. The preferred embodiment of the ADFM system comprises the following seven functionalities:
1 ) Displaying digital well logging data such as digital well logs, micro-s formation imaging, etc. for use as a depth reference;
2) Registering (assigning) core depths on raw digital images;
3) Performing core depth correction using digital well logging data and digital core images;
4) Selecting samples on digital core images;
5) Calculating sample depths;
6) Annotating raw digital core images with desired labels and generating composite digital images that combine raw digital core images with annotation for core photograph hardcopy printing (annotations may include sample intervals and sample numbers, core top/base depths, meter depths, well name, company name, company logo, depth scale bar, plus other labels);

7) Calculating volume of shale directly from digital core images;

8) Functionalities for enabling geologists to record their core descriptions and export the results, including facies (rock groups) determinations; and 9) Exporting results.
The ADFM system preferably produces the following five sets of results:
1 ) Corrected core depths, with lost core interval depths, for core box labelling;

2) A sample list with corrected core depths, NA (Not Analyzed) intervals and lost core intervals;
3) Annotated digital core images that are ready for hardcopy print on photographic paper (annotated images are also provided by paper copy to the lab to assist in physical sampling on sample-side cores, according to sample intervals annotated on the images);
4) VSH and facies results; and 5) Selected content of the Depth Correction Window.
One implementation of the preferred embodiment of the ADFM system has demonstrated that the ADFM system can reduce the time from the digital imaging stage to the physical sampling stage from 17 to 22 hours per oil sands well to approximately 3 to 5 hours. It can also reduce the number of required personnel from five people (as required in the traditional workflow) to two people (in the ADFM system - one photographer for digital imaging and one geologist for operating the ADFM system). With ADFM, more accurate core depths and sample depths can be produced. A core photo hardcopy can be printed out on photographic paper immediately upon completion of the desired processing and delivered to the oil company within 1 to 2 days, since core depth correction, sample selection and image annotation are handled by one geologist in a very efficient and consistent way. This is in contrast to the traditional physical core workflow where one might wait 1 to 4 weeks before digital image printing, since information for annotation is obtained from different sources: (1 ) core depths are provided by a geologist, (2) meter depths and sample intervals are provided by a lab technician, (3) most labels are put on by a photographer, and (4) the remaining labels such as company name, well name, etc. are added by an image editor.
ADFM System Referring now in detail to Figure 3, an ADFM system according to the present invention is illustrated for executing a method according to the present invention.
As can be seen, an ADFM user 31, with access to the ADFM system 32, is connected through the Internet 33 to a data server 34 to retrieve their assigned privileges from the data server 34, as described in detail below. The user 31 is provided with digital images and well logging data either through the Internet connection or by means of portable storage media 35. The clients 36 (oil companies, labs, etc.) provide raw data to users by uploading raw data to the data server (by browser or ftp client 37) or through portable storage media 35, the users 31 typically being geologists or other earth science professionals employed by the oil company 36 as full-time or contract workers to analyse the raw data from the clients 36 and then upload analyzed results to the data server 34. The users 31 can also deliver results (for example, back to the oil company 36) through portable media 35 or paper copy. Clients 36 or any authorized users can browse or download results from the data server 34. When raw data is provided in a digital format (digital core images and digital well logging data) and results are delivered in a digital format, ADFM users 31 can accordingly remotely perform core logging work without ever looking at any physical cores in a traditional lab, and can provide their services to different clients globally, which is logistically extremely difficult to achieve in the traditional physical core workflow.
The preferred embodiment of a method according to the present invention comprises a series of stages, namely Program Initiation, Depth Registration, Depth Correction, Annotation, Finalizing Annotated Images, Sample Selection, VsH (shale volume) Calculation, Facies Interpretation, and Result Export (including Depth Correction Window Export). These stages each have their own corresponding module, as is illustrated in detail in Figure 4, and will each be addressed in detail in the following, with reference to the accompanying drawings.

PROGRAM INITIATION
Referring now in detail to Figure 5, Program Initiation begins when the program is accessed by a user. As the preferred embodiment is web-based, the user would utilise an Internet connection to log onto the server to obtain the assigned privileges from the data server. The user will be presented at step 50 with a window (see Figure 6) that enables entering a username and password, which username and password will have been set up and stored in the data server before the user requires access to the ADFM program. The preferred user verification process is of a commonly employed form. When the user enters their username and password at step 50, the program will connect to the database server to retrieve pre-assigned access privileges at step 51 using the username and password. If the combination of the username and password exists in the data server, the program will enable or disable certain modules (see Figure 4) of the ADFM system based on the retrieved access privileges. If, for example, the retrieved value for a module is 1, the module is enabled; if the retrieved value for a module is 0, the module is disabled.
Once user verification is accomplished and the user has been provided access to the full program functionality, the next step is to create a "project" at step 52. To do this, the user enters a project name in an input window (such as that shown in Figure 7); the project name then becomes the name of a folder on the hard disk.
The user is preferably given a number of options after the new project is created:
a) Open a project, which enables the user to select a project folder and set it as a working project;
b) Save, where information is saved;
c) Save as, to save a project under a new name; and d) Exit, to quit the program.

The next step 53 is to add the name of a well (one well at a time) to a working project, thereby creating a placeholder. The user can add as many wells to a project as desired. Where a number of wells are added, a well list will be generated and saved for access by the user in selecting a "working" well for the given project. The user will be presented with options regarding wells:
a) Add, to add a well to the current project; a well name is provided by the user (as shown in Figure 8); when a well is added, a folder with that well name is created;
b) Export, to save well information of the selected wells) from the current project into a file;
c) Import, to import well information from a file created in Export from another existing project;
d) Delete, where the well list is displayed for the user to select a well to delete; and e) Select, where a well can be selected from the well list under the current project as the working well.
After a well is added to a project, the next stage, then, is for the user to load digital core images at step 54, the raw digital images being previously received from an oil company. The raw digital core images can be loaded from portable storage media or downloaded from the data sever (see Figure 3), depending on how the raw data was provided by the client. A well is usually represented by to 25 images in any image format, which images are presented in file list form in a typical file-open window and can be loaded one-by-one or all at once. The user will again be presented with options:
a) Load, to load images into the current well; a "file open" window is presented to enable the user to browse and select images to load;
b) Select, to select an image from the image list of the current well as the working image and display it in the Depth Registration Window (discussed below); on the list, images that have been depth-s registered are separated from the rest with a special sign or marker; and c) Delete, to delete selected images (one or more) from the well.
In the Depth Registration Window (illustrated in Figure 12 and discussed in detail below), the selected image can be zoomed in, zoomed out, or rotated 90°
left or right. Three special zoom functions are also available: 1:1, Fit-all, and Fit-width, the default being Fit-all. Four image navigation buttons are also provided:
First, Previous, Next, and Last. The Depth Registration Window is a workspace on the screen for use in engaging in steps related to the raw digital core images.
Three modules (see Figure 4) are associated with the Depth Registration Window: (1 ) the Depth/sample Registration Module for registering core depths and selecting sample intervals; (2) the Facies Registration Module for selecting facies top/base depths; and (3) the Annotation Module for adding, displaying, and manipulating annotation.
Once the raw image has been selected at step 55, the program will then display the core image in the Depth Registration Window (as shown in Figure 11 ), labelled only by core number and box number; note that the core number defines a discrete section, or "run", of core (usually 3m in length for oil sands cores), while the box number identifies the box where the actual physical cores are stored. While digital image providers normally must spend a substantial amount of time providing detailed annotation before shooting digital images, the limited annotation requirements of the present invention enable a relatively rapid shooting of digital core images, cutting down considerably on their acquisition time. Traditional core labs will normally have to manually insert information, such as by putting magnetic stickers of sample intervals, sample numbers, core top/base depths, core meter depths, etc., on a metallic framing structure to label cores, before taking any digital photographs, and hence there is a substantial time savings in a method according to the present invention, normally reducing the required time from 3 to 4 hours per oil sands well to less than one hour.
DEPTH REGISTRATION
The next stage of the ADFM process is Depth Registration (step 56 of Figure 5).
A flowchart illustrating the steps of the depth registration stage is presented in Figure 9, which steps are explained in greater detail below.
First, the user must select an image at step 91 to display it in the Depth Registration Window and then define a "digital ruler" at step 92, which digital ruler will be employed by the program to determine an exact, actual length of the interval in question. To define the digital ruler, the user right-clicks (using the mouse) anywhere over the displayed image to display a pop-up menu and then selects "Define digital ruler" from the menu. The user clicks on any two points on the displayed image and a "Define digital ruler" window is popped up (see Figure 10), including the horizontal distance on the digital image in term of pixels between the clicked two points (2389 pixels in Figure 10), and two radio buttons for selection (one for 0.75m and the other for an alternative length defined in the user-input box). When the OK button is clicked, the window closes, which establishes a user-defined relationship between digital image sizes in terms of pixels and physical core lengths in terms of meter. For example, if the 0.75m radio button is selected, the program defines a digital ruler in which 2389 pixels on the image are equivalent to 0.75m of physical core length. This relationship will be maintained and used to calculate core length during the core depth registration process until a new digital ruler is established.

Once the digital ruler is defined, depth registration proceeds by means of the Smart Depths process, details of which process follow with reference to Figure 12.
According to the Smart Depths process, the user will select top and base depth points using the mouse to define a desired interval, and there can be multiple selected intervals within the same digital image. The user selects the top and base depth points by clicking at two locations on the image itself at step 93.
The program then measures and crops a rectangular area (a depth registration rectangle) between these top and base depth points for later use and pops up a Smart Depths window at step 94 for the user to input/confirm depth registration information for the interval defined by the depth registration rectangle.
Depth registration information includes core identification (core number, box number and interval number) and both top and base depths.
Core identification is then assigned in the following manner: the user will manually input a core number in the Smart Depths window, and the program will then automatically determine the proper box number. For example, using common digital images where a typical core is 3m, there are two physical core boxes (representing 1.5m of physical core each). The first physical core box has the number "1" as its box number and the second physical core box has the number "2" as its box number. Each 1.5m core box will result in two 0.75m image sections, which are labelled "A" and "B", respectively. As a result, core box identification will have a format such as 1A, 1 B, 2A, 2B, etc., where "1"
and "2" provide the physical core box sequence and "A" and "B" represent the first and second 0.75m core within a physical core box. The program automatically advances the box number from 1 A to 1 B, 2A, 2B, 3A, etc., when one Smart Depths window is completed and the user proceeds to define the next adjacent displayed interval (a new Smart Depths window is employed for each subsequent selected interval). This automatic advance in box number can be altered by the user if desired at step 95.
For the first Smart Depths window representing the most shallow core interval, the user will manually input the top depth, which will normally be determined in the field by coring personnel, and the program will then automatically determine the base depth based on the digital ruler and the distance on the image between the two clicks. The base depth will be remembered by the program and used as the top depth for the next adjacent descending core interval (the last depth from the former Smart Depths window cannot be changed by the user within the new Smart Depths window, but the user can amend the top depth in the new Smart Depths window at step 95).
When moving on to the next core, the user will manually input a new core number in the Smart Depths window, otherwise the program will assume that the user is still working with the previous core interval and only update the box number. The program will then automatically reset the box number to 1A and calculate the new interval length and the base depth; the interval number is specified by the user and remains the same until it is changed again. After the user makes necessary changes at step 95, the user will be presented with the option of either accepting the edit at step 96a or cancelling the edit at step 96b.
If "Accept" is chosen, the program will crop out the rectangular portion, save it with its core identification and top/base depths at step 97, and automatically annotate each registered interval with the core number, box number, interval number, and top and base depths, in a program-defined format (as shown in Figure 12).
The user can repeat steps 93 through 97 until all core intervals on the image are depth-registered. The user then moves to the next image to do depth registration at step 98.
Although the preceding has been presented as a top-down registration process, registration can be conducted top-to-bottom or bottom-to-top, at the option of the user. The program automatically determines whether registration is being conducted top-to-bottom or bottom-to-top, based on the relative positions of the two mouse-selected points and their order of selection. If the user changes registration direction during the process, however, the user will need to ensure that the depths are being accurately determined, and the user may need to manually amend the core/box/interval number if necessary when the first Smart Depths window is popped up after a change of depth registration direction.
Depth consistency is also checked by the program, such that shallower depth images cannot be overlapped with or displayed as being deeper than any deeper images.
Having completed the initial depth registration steps, the registration information can be modified by the user at this stage. If the user clicks anywhere within a selected depth registration rectangle, the depth registration window is popped-up with the associated information, including top/base depths and core length.
The user can also change the core/box/interval number. However, any change in one depth registration rectangle will not trigger changes in other depth registration rectangles, so the user will need to revise other interval information as desired.
The user can also delete registration information by entering depth deletion mode, which enables deletion of a selected piece of information or all depth registration information for the core image, and start again.
Once the user has completed all depth registration for the digital core images, the user can then close the core image window and proceed to core Depth Correction in the Depth Correction Window. Optionally, the user can select and register sample intervals, as well, at step 57 of Figure 5. Sample selection will be described in detail below.
DEPTH CORRECTION

The Depth Correction Window is the workspace on the display wherein the user performs all actions related to stacked images that are cropped from raw digital core images, which cropped images were defined by depth registration rectangles during the depth registration process in the Depth Registration Window.
After core depth registration is completed for all raw digital core images, the user will then load corresponding well logging data at step 58 (which provides depth reference, so the well logs are sometimes termed "depth reference logs"), enabling correcting of the core depths at step 59 below. The well logging data can include GR, porosity, resistivity, dipmeter logs and/or high-resolution borehole image logs such as formation micro-imaging (FMI) logs. Well logging data can be provided in an oil industry standard format such as LAS or a digital image format (such as .tif or .jpeg) by oil companies, as was the case with the digital core images, and the user accesses the well logging data by means of the well logging data selection window shown in Figure 13.
As is shown in Figure 17 and described in greater detail below, the program then displays in the Depth Correction Window (1 ) the stacked, cropped core images (that have just been registered) in a vertical orientation (the images possibly being highly compressed depending on the depth scale used), (2) the corresponding core identification, and (3) the well logging data. All of these three pieces of information are displayed according to depths, and the depth scales in the Depth Correction Window can be changed by the user. In this preferred embodiment, there will be two vertical core image stacks, one displaying the cropped images according to their registered depths and the other displaying the cropped images according to either their registered depths or corrected depths at the user's option. The second stack is used in the depth correction process detailed below (and illustrated in Figure 15). Any lost core intervals (depth gaps between any neighbouring cropped images) are filled with a highlight colour, such as red.
With depth reference well logs, stacked core images and corresponding core identification displayed side-by-side on the display device, the user begins the stage of core Depth Correction (step 59 of Figure 5). Depth correction is to recalculate the top/base depths of each cropped image based on depth markers selected by the user and save the results for further analysis.
The first step in the depth correction stage is to pick depth reference markers, which is illustrated in the flowchart of Figure 14. Depth reference markers will usually be selected on the basis of some visible feature of importance, such as a lithology change; they are special contacts that can be easily identified on both well logs and core images by geologists. The user will select the marker-picking icon or a marker-picking menu to enter the marker-picking mode at step 141, in a manner well known to those skilled in the art. The user can then manually pick corresponding markers on the well log and the digital image at step 142, said depth markers being "picked" by clicking the mouse when the cursor is over the desired point on the well logs and then the core images.
As is shown in schematic form in Figure 15, once corresponding markers are selected, the program will insert horizontal lines 151 and 152 through each of the well logs and the core images, respectively, and then also insert a correlation line 153 connecting those two horizontal lines. As many markers as are desired may be selected. The user can delete markers, as well, either a single selected marker or all markers.
Given the highly-compressed nature of the displayed images, there may be some error where the user has been relying on their own visual inspection of the displayed images to conduct marker-picking. The next step 143, therefore, is for the user to fine-tune the markers - to position a marker to an exact position at the user's choice. The user enters the fine-tune markers mode by selecting a fine-tune markers icon or fine-tune markers menu, which will pop-up a floating window (which is shown in schematic form in Figure 16 and in a screen shot in Figure 17). The floating window (fine-tune marker window) displays a drop-down list 161 of all the markers that have been picked and a zoom-in 162 of a small section of the digital image centring around the current active marker 163.
The active marker 163 is the same one displayed in both the floating window and the stacked core images in the Depth Correction Window. The user can set a marker as active, in the fine-tune markers mode, by (1 ) double-clicking a marker in the Depth Correction Window or (2) selecting a marker on the drop-down marker list under the zoom-in 162 in the fine-tune markers window. When the position of an active marker 163 is changed, the zoom-in 162 image will be updated accordingly, and the new active marker 163 is highlighted in the Depth Correction Window with a highlight colour defined in the program.
In addition to the pop-up of a floating fine-tune markers window, entering fine-tune marker mode will display the difference 164 in thickness (the thickness being between any two adjacent markers) of a corresponding well log and stacked core section in the Depth Correction Window. The preferred thickness difference unit is centimetres (e.g. the thickness difference 164 is 20cm in Figure 16). When the thickness difference exceeds a certain established value (threshold value), the thickness difference is highlighted with a highlight colour as defined in the program to indicate a substantial thickness difference that the user may wish to examine in detail.
With the help of a floating window, the user then has a more magnified display of the digital image immediately surrounding the selected marker, and the mouse is then employed to drag the marker line 163 into a more desirable position based on the magnified visual inspection. The active marker 163 can also be dragged in the Depth Correction Window itself, and dragging in either window automatically updates the marker in the other (and the thickness difference is updated accordingly).
After all markers are fine-tuned and moved to their correct positions on both core images and well logs, the thickness difference between any two neighbouring markers should preferably be zero or close to zero, since the markers for any corresponding well log and core image are intended to refer to the same contact in the subsurface. If the thickness is not zero, the geologist must decide, based on their professional knowledge and experience, what may have caused this difference and take actions accordingly to render the thickness difference zero.
There are three key potential causes for the geologist to consider: (1 ) lost core intervals have been recorded incorrectly in the field; (2) cores have been misplaced or are upside-down; and (3) core expansion. Any one of these, or any combination thereof, can cause a non-zero thickness difference.
Lost core adjustment takes place at step 145. If there is a lost core interval which is too thick (when compared by the program to the well logging data), which can be indicated by a sign in front of the thickness difference value (e.g. a "-" sign), the user places the mouse over the lost core interval and right-clicks the mouse to select the "Delete lost core" menu. A Lost Core Deletion window is popped up (as is shown in Figure 18), showing the maximum lost core thickness that can be deleted and an input box for the user to specify the lost core thickness for deletion. The maximum thickness is the total thickness of the lost core interval at this position. When the "OK" button is clicked, the specified lost core thickness is deleted and all of the top/base depths of all cropped images below the lost core interval are shifted up by the specified (deleted) thickness.
A lost core interval can also be inserted into any join between two neighbouring cropped images. To do this, the user will place the mouse over a desired join and right-click the mouse to select the Insert Lost Core menu, and a Lost Core Insertion window is then popped up (as is shown in Figure 19), with an input box provided for the user to specify a lost core thickness to be inserted at the join.

When the "OK" button is clicked, the specified lost core interval is inserted into the join. If a lost core interval exists, the specified (inserted) lost core interval is added to the existing interval. The program will then shift down the depths of all cropped images below the insertion join by the specified (inserted) thickness.
The displayed core intervals (cropped core images) can each be moved interactively up and down (if inaccurate vertical positioning is determined to have occurred) at step 144 or rotated 180° (if it is determined that core was accidentally placed upside down, either in the field or during image shooting), if there is an error clear from visual inspection of the well logging data and digital images. When a cropped image is moved from one place to another, a void (_ lost core) is left at the old position; a prompt is provided as to whether to delete the void or not. The depth of all markers and cropped images below the old or new position, whichever is shallower, may need to be adjusted.
Core expansion is handled by the program automatically by shrinking cropped image lengths to their corresponding lengths at the subsurface.
After lost core interval adjustment 145 and core order restoration 144, depth correction of the stacked core images on the Depth Correction Window can be performed. The user selects a depth correction icon or menu, whereupon the program displays a table showing raw top/base depths and corrected raw/base depths for all core boxes or cropped images, plus their thickness before and after depth correction, for the user to review. The positions of all of the markers are displayed, as well. "OK" and "Cancel" buttons are provided on the table for the user to confirm or cancel the action of depth correction. If the "OK" button is clicked, the program then automatically performs depth correction at step 147, which calculates corrected top/base depths of all cropped images and adjusts core expansion (if any exists), resulting in a display as shown in Figure 20.
Corrected top/base depths for all cropped images can be "locked" and remain stable unless they are overwritten by the user by "locking again". As can be seen in Figure 20, two stacked core image columns are presented, the first representing the uncorrected depths and the second being updated so that all cropped images are displayed according to their corrected top and base depths.
All markers picked on the core images will be aligned by the program at the same level as their corresponding markers picked on the depth reference logs, such that the two horizontal lines 151, 152 and the correlation line 153 connecting the two horizontal lines 151, 152 will then appear as one horizontal line. Note that the second column of cropped images need not provide the corrected depth information; in other words, the first and second columns may instead be presented in identical form (if it is desired, for example, to have two separate users each correct the uncorrected information for comparison purposes).
Any given top or base will have two associated depths: a Raw Depth that was assigned during depth registration, and a Corrected Depth that was calculated when depth correction was performed. In addition, there is a Current Depth, which is a working copy of top and base depths of cropped images. Before depth correction is performed, Corrected Depth = Raw Depth. When displaying the depth information, the program will offer the user with options as to whether to use Raw Depths or Corrected Depths.
Once correction is completed, the corrected information can be exported as displayed or in text/table format at step 148 (part of step 60 of Figure 5).
Corrected cropped image top/base depths are used to calculate core top and bottom depths, and meter depths. Core top/bottom depths and meter depths are used for annotating raw digital core images, as described in detail below.
The depth correction process traditionally takes three to four hours for a typical oil sands core length, but this time is cut to less than one hour with the ADFM
method according to the present invention.

ANNOTATION
After correction of the registered depths, the user can proceed to annotate the digital images at step 61. As stated above, annotation has traditionally been conducted by placing magnetic stickers on a metallic framing structure on the core box, before any digital images are even taken. With the ADFM process, the use of digital images as early as initial depth registration means that all corrected depth information is easily accessible and can be presented directly on the digital images themselves.
To begin, the user activates the Annotation Module in the Depth Registration Window by clicking an annotation icon or by selecting an annotation menu, and the program automatically transfers the corrected core top and base depths and annotates them on the digital images; the program will also automatically calculate the position for every meter depth and mark the position with a mark and display the depth value adjacent the calculated position. This can be seen in Figure 21. If samples are selected, as described in detail below, the program will automatically annotate sample labels, sample numbers, and sample start and end marks such as arrows. If lab analysis results from any samples are available, an option can be turned on to display lab results adjacent their corresponding sample labels. If facies have been interpreted, as described in detail below, facies identification indicators can be annotated on the digital image with a corresponding facies colour.
Annotations displayed on core images by the Annotation Module can be moved by click-and-drag of the mouse, to assist the user in ensuring that the digital images are not obscured by the labelling.
FINALIZING ANNOTATED IMAGE
Once the raw digital core images have been annotated at step 61, the user can finalize the annotated images at step 62. To finalize the annotated images, the program can add a frame, company name, well name, the digital ruler, the client's company logo, etc. Any of this information can be included or excluded at the user's choice. Figures 22 and 23 illustrate the type of information that may be included when finalizing the annotated image. A final, printable copy of the annotated image, in the user's choice of digital image format, is then generated automatically by the program at step 63. The user may then print off the finalized annotated image at this stage or deliver it to the client by portable media or uploading to the data server (for the client to download or browse through the Internet).
SAMPLE SELECTION
A large number of rock samples are routinely taken from oil sands cores for analyzing bitumen weight percentage in order to determine the richness of bitumen. Sample intervals are selected on view-side cores by a lab technician and marked on the core boxes. The digital photographer traditionally positions sample labels according to these marks before shooting the digital core images.
The digital images with sample sticker labels are then used to translate sample intervals to frozen sample-side cores to enable physical sampling. This traditional sample selection/translation approach usually involves two people, and is time-consuming and prone to errors.
To sample according to the preferred embodiment of the present invention at step 57, the user selects a Sample Registration menu or clicks on a Sample Registration icon to enter the sample selection mode. In the sample selection mode, the user selects a sample interval by clicking on two points on the digital core image. The two points have to be within a depth registration rectangle so that sample depths can be calculated based on the positions of the two points related to core depths. After the two clicks are completed, a Sample Registration window is popped up (as shown in Figure 25) asking for three inputs from the user: (1 ) Label (which indicates the kind of sample with a suggested value that will remain the same unless the user makes a change to it); (2) Number (the sequence number for the same kind of sample, which automatically increases by one after every successful sample registration; the value will be re-set to "1"
when the Label input box is changed by the user, and the value can be overwritten by the user); and (3) two radio buttons for "Yes" and "No" to indicate if the sample number is to be displayed in the sample annotation ("Yes"
indicates real samples and the sample information will be annotated on digital images;
"No" is for "false" samples and is only for text annotation where only the Label value will be annotated on digital images). After "OK" is selected, the sample intervals are displayed with two marks (for example, two arrows) to show the start and end points of sample intervals, as is shown in Figure 24. If the two clicks cover a lost core interval, an error message will be displayed and the sample selection attempt will fail.
When the Annotation Module is activated and the program is in annotation mode, the sample marks will be automatically moved out of the depth registration rectangles and placed at some defined distance above the top of the rectangle within which they reside in the sample selection mode. Lab analysis results may also be displayed or annotated on the digital core images, beside the sample label and number, which is very useful for any lab result quality checking.
Sample registration values can be edited or deleted in a manner similar to core depth registration. A sample list table with corrected top/base depths and sample length can be exported in different text formats at step 60. NA (Not Analyzed) intervals and lost core intervals can be included in the table so that the lab can directly use the output in their lab report, saving the lab a few hours in manually generating the similar output.
VSH CALCULATION
The use of digital core images throughout the process, however, adds additional functionality to the ADFM process. Geologists often need to determine the volume of shale (VSH) in a given oil sands core in order to assess oil sands reservoir quality, and the ADFM VSH Module provides a novel means of achieving that goal. Bitumen-saturated oil sands are essentially black in colour, while shales are light to dark grey. This characteristic feature of oil sands makes calculation of VSH directly from digital core images possible.
Regions of the digital image are selected at step 64 to represent sand, shale, dark shale and water/gas sand. These selected regions of the digital images are used by the program to generate Red, Green and Blue (RGB) histogram curves for each corresponding rock type in a sand/shale calibration window (see Figure 26).
Referring to Figure 26, based on the histogram curves for different kinds of rock types, the user specifies Red, Green and Blue (RGB) threshold values for shale and dark shale. Threshold values are displayed as interactively-movable (by means of the mouse) vertical lines on the RGB histograms which essentially divide the RGB index of 0 to 255 into four regions: sand, dark shale, shale and gas/water sand, from which the VSH can be determined:
VSH = (shale region + dark shale region)/(all four regions) After the four regions are defined, the top and base of a cropped image interval can be specified so that the raw core image and interpreted sand/shale (in black and white) of the interval can be displayed side by side to allow assessment of the validity of the selected threshold values. When the threshold values are changed, the sand/shale interpreted image is updated accordingly.
The user specifies VSH calculation options (as can be seen in Figure 27), which options include Sampling window (the depth interval of cropped images within which all pixels will be included to calculate VSH) and Sampling step (the depth difference between two nearby VSH value points).

Using the top depth of the shallowest cropped image as the starting point, the program calculates VSH at the depth for every sampling step, based on RGB
threshold values for shale and dark shale as determined in the calibration step and the VSH calculation formula discussed above. The sampling window is the interval of images centred around a sampling point. If the sampling point is within a lost core interval, no value is calculated. If the sampling window includes lost core, the lost core interval is ignored.
With the threshold values determined, a pixel that has RGB values within shale or dark shale RGB regions is classified as shale; outside the ranges is classified as sand. The program then calculates a VSH value at every VSH depth point and with all pixels in the corresponding sampling window, and plots a VSH curve in the VSH track in the Depth Correction Window (see Figure 28) at step 65. The VSH
curve can be exported in the LAS format, a commonly used industry standard for recording well logs data, at step 66.
VSH calculation and display is handled by the VSH Module in the ADFM System.
FACIES INTERPRETATION
Oil sands projects are capital-intensive and oil companies spend considerable funds and effort in trying to characterize oil sands reservoirs, including building 3D facies models. Traditionally, 3D facies modellers spend 60 to 70% of their time and effort in compiling data in an appropriate format to enable them to load the data into their 3D facies modeling software. The ADFM Facies Module is designed specifically for generating facies results that can be imported into many 3D facies modeling software programs.
According to the preferred embodiment, the user defines a facies at step 67 by means of facies code (ID), facies colour, facies name, and minimum and maximum VSH cut-offs (see Figure 29). The facies code is unique and can be composed of a number, letters or a combination of both. Two facies columns are preferably provided on the Depth Correction Window, adjacent to the stacked digital core images, displaying the user's facies determinations (as described below). Once the various facies are defined by the user, facies can be interpreted automatically (step 68 of Figure 5) or interactively (step 69 of Figure 5). Facies can be auto-filled in one facies column in the Depth Correction Window based on the calculated VSH curve and facies VSH cut-offs, and the automatically-filled facies can be modified interactively by the user. Facies can be copied from one column to the other.
An interactive facies interpretation process is shown in the flowchart of Figure 30.
The user enters the interactive mode at step 300 by selecting an interactive menu or by clicking an interactive icon, whereupon a floating window showing the defined facies list is popped up (Figure 29). The user then selects a facies from the floating window at step 301, places the mouse cursor over a facies column or core image at step 302, and clicks on two points on the facies column or core image to define the top and base depth of an interval at step 303. If the mouse action is in Facies Column 1 (step 304a), the program sends the facies ID and top/base depths to Facies Column 1 at step 304b. If the mouse action is alternatively in Facies Column 2 (step 305a), the program sends the facies ID
and top/base depths to Facies Column 2 at step 305b. If the mouse action is alternatively on a digital core image in the Depth Registration Window (step 306a), the program sends the facies ID and top/base depths to a facies column in the Depth Correction Window at the user's choice at step 306b.
The selected interval is then filled with the predefined facies colour of the selected facies in a corresponding facies column at step 307, and the facies file is updated and saved at step 308. Any previously-established facies within the interval is replaced with the new facies. If facies above or below the interval are the same as the new facies, they will merge into one facies interval. If the new interval is inserted in the middle of an existing facies interval, the existing facies interval is split into two intervals divided by the new facies.
Where two geologists are engaged in facies determination and each provides a facies interpretation of the core on the same well, the program can provide two parallel facies columns in the Depth Correction Window with one facies ID
column or two displayed beside the facies columns. If there is only one facies ID
column, the displayed facies ID can be associated with either facies column.
Each geologist, being a separate user, would independently access the ADFM
system and conduct their own facies analysis. If desired, one geologist can copy the other geologist's facies column over to his own column and then make changes to the copied facies. This is extremely useful, for example, where a senior geologist is engaged in quality control of a junior geologist's facies interpretation; the senior geologist can make changes on his own facies column without losing the junior geologist's work. It is also very useful for an office geologist when refining an external consulting geologist's interpretation.
A core/facies description column (or "notes") can also be added adjacent to the facies columns) for the user to type in a description of the interval.
Horizontal lines can be drawn in the description column to divide different description text blocks, as can be seen in Figure 28.
Finally, facies information can then be exported in text/table or LAS format at step 70 and the data uploaded to the data server at step 71. Once the facies file has been updated and saved at step 308, the user can exit the module at step 309.
DEPTH CORRECTION WINDOW EXPORT
Information can be exported by the program by means of text/table or LAS
format, but the Depth Correction Window itself can also be exported. Any column in the Depth Correction Window can be turned on or off, and the width and orders of columns can be changed at any time by the user. The content displayed in the Depth Correction Window can be exported as a digital image in any format or in a .pdf file.
Referring now in detail to Figure 28, the columns of the Depth Correction Window available for export are as follows:
1 ) Gamma: (1 ) 0 - 150 API from left to right or 150 - 300 API; (2) depth/unit lattice;
2) Depth: (1 ) display scale and depth values; (2) depth value display depends on scale;
3) Density porosity (DPHI) and neutron porosity (NPHI) on the same track:
(1 ) fraction scale from 0 to 0.6; (2) curves in different colour;
4) Resistivity: (1 ) display shallow, medium and deep resistivity curves in different colours in log scale; (2) 0.2 - 2000 ohm.m;
5) Borehole imaging column: display borehole imaging logs, such as Formation Micro-Imaging (FMI);
6) Correlation columns which display the correlation lines that connect the corresponding markers on the well logging data and the stacked core images, and the correlation lines can be turned on or off;
7) Core image 1: (1 ) display cropped images according to their raw depths and the depth scale;
8) Image identifier: (1 ) display identifier of cropped images on core image column 7 and (2) draw a line between cropped images of column 7;
9) Core image 2: (1 ) display cropped images according to their raw depths or corrected depths and depth scale;

10)Image identifier: (1 ) display identifier of cropped images on core image column 9; (2) draw a line between cropped images;

11 )VSH column: (1 ) display the VSH (volume of shale) curve in fraction scale of 0-1; (2) highlight selected VSH cut-offs defined in facies definition by the user in different colours;

12)Facies column 1: (1 ) Colour fill facies;

13)Facies ID column: (1 ) display facies ID associated with Facies column 1 or Facies column 2 at the user's choice; (2) draw a horizontal line between neighbouring facies intervals;

14)Facies column 2: (1 ) Colour fill facies; may be identical to Facies 1 or present an alternative interpretation, at the user's choice;

15)Sample column: (1 ) display sample intervals; (2) if lab results are available, display lab results as a curve or histogram;

16)Notes: (1 ) multiple comments blocks divided by horizontal lines.
TEXT INFORMATION EXPORT
In addition to the ability to export the Depth Correction Window itself, the program enables the export of information in text form. An Export function is provided to enable the export of information relating to corrected core depths, VSH values, and facies. The user can choose what information combination from designated wells) to export from a well list, the information including:
a. Core depths: export corrected core box depths.
Format: Core No., Box No., Top depth, Base depth, Core corrected_length, Core_physical_length, Length difference b. Sample list with corrected sample depths and lengths. Lost core intervals and NA (Not Analyzed) intervals can be included, as well.
Format: Sample label, Sample number, Top depth, Base depth, Sample thickness c. VSH and Facies curves: export VSH and facies information in an industry standard LAS format.
Format: Depth, VSH, Facies code, Facies name d. Facies only: export facies in the interval format. For every facies interval on a facies column in the Depth Correction Window, there will be one row of data.
Format: Top depth, Base depth, Facies code, Facies_name ANNOTATED DIGITAL CORE IMAGE EXPORT
Composite images can be generated in any digital format. Composite images can include raw core images overlaid with different kinds of labels, such as sample labels, top/base depths of core intervals, meter depths, and image frame with information such as company name, well name, company logo, scale bar, etc. If lab results for samples are available and facies have been interpreted, sample results and facies ID can be annotated on the images, as well. Any kind of label can be turned on or off at the user's choice.
The foregoing method is preferably applied within a system including the modules as set out in the schematic illustration of Figure 4, which schematic illustration illustrates the data flow. The flowchart of Figure 5 illustrates the entire preferred ADFM process as described in detail above.
As is clear from the foregoing, there are substantial advantages to the present invention when compared with traditional core logging techniques. As can be seen in Figures 1 and 2, which respectively illustrate the ADFM Digital Core Workflow and Traditional Physical Core Workflow, the ADFM Digital Core Workflow using digital images in initial depth registration and throughout the remaining processes can result in substantial time savings and reduce the number of people involved. The composite impact is an efficient digital workflow with which information can be quickly and remotely processed, and the results can be delivered promptly to oil companies.
While a particular embodiment of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention and are intended to be included herein. It will be clear to any person skilled in the art that modifications of and adjustments to this invention, not shown, are possible without departing from the spirit of the invention as demonstrated through the exemplary embodiment. For example, the method could be embodied in a software product that a user could purchase, rather than utilising a password-protected on-line environment. The invention is therefore to be considered limited solely by the scope of the appended claims.

Claims (18)

1. A method for processing data for use in correcting downhole core depth information comprising the steps of:

a. accessing electronic data comprising at least one digital image of a core sample from a well;

b. displaying the at least one digital image on a display device;

c. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;

d. establishing an approximate actual depth value for the first depth of the displayed interval;

e. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval; and f. saving the displayed interval image and information comprising the approximate depth values for the first depth and second depth for use in correcting downhole core depth.

2. A method for processing data to correct downhole core depth information comprising the steps of:

a. accessing electronic data comprising at least one digital image of a core sample from a well;

b. accessing well logging data corresponding to the core sample;
c. displaying the at least one digital image on a display device;

d. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;

e. establishing an approximate actual depth value for the first depth of the displayed interval;

f. measuring or calculating the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval;

g. displaying the well logging data adjacent the displayed interval as the depth reference;

h. comparing the well logging data and the displayed interval; and i. correcting the first depth and the second depth; and j. saving the displayed interval image and information comprising the corrected first depth and second depth.

3. A method for processing data on-line for correction of downhole core depth information comprising the steps of:

a. providing a web portal for accessing electronic data comprising digital images and well logging data and a data server for storing the digital images and the well logging data;

b. transferring electronic data comprising at least one digital image of a core sample from a well to the server;

c. transferring electronic data comprising well logging data from the well to the server;

d. displaying the at least one digital image on a display device;

e. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;

f. establishing an approximate actual depth value for the first depth of the displayed interval;

g. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval;

h. downloading and displaying the well logging data adjacent the displayed interval;

i. comparing the well logging data and the displayed interval;
j. correcting the first depth and the second depth; and k. saving the displayed interval image and information comprising the corrected first depth and second depth.

4. The method of Claim 1 or 2 wherein the providing of the at least one digital image of a core sample from a well is achieved by obtaining the at least one digital image from an oil company.

5. The method of any one of Claims 1 to 3 wherein the display device is a computer monitor receiving signals from a user computer workstation.

6. The method of any one of Claims 1 to 3 wherein the displayed interval is selected by means of:

positioning a mouse cursor over a first location on the displayed at least one digital image representing the first depth;

clicking a mouse button to select the first location;

positioning the mouse cursor over a second location on the displayed at least one digital image representing the second depth; and clicking the mouse button to select the second location.

7. The method of any one of Claims 1 to 3 wherein the first depth represents the top depth of the displayed interval, and the second depth represents the base depth of the displayed interval.

8. The method of any one of Claims 1 to 3 wherein the first depth represents the top depth of the displayed interval, and the second depth represents the base depth of the displayed interval.

9. The method of any one of Claims 1 to 3 wherein the approximate actual depth value for the first depth is established based on field data.

10. The method of any one of Claims 1 to 3 wherein the length of the displayed interval is measured by means of a predetermined digital ruler that equates pixel numbers with a set length value.

11. The method of Claim 2 or 3 wherein the accessing of the well logging data is achieved by obtaining the well logging data from an oil company, government agency or any service provider.

12. The method of Claim 2 or 3 wherein the comparing of the well logging data and the displayed interval is achieved by means of displaying the well logging data and the displayed interval in parallel, adjacent orientation, enabling a user to visually inspect the well logging data and the displayed interval for correlation purposes.

13. The method of Claim 2 or 3 wherein the correction of the first depth and the second depth is achieved by means of:

allowing a user to pick corresponding markers on the well logging data and the displayed interval, by means of mouse cursor positioning and location selection;
inserting correlation lines connecting the corresponding markers;

inspecting the digital interval to determine if there are any lost core intervals;
adding any desired sub-intervals to the displayed interval to represent lost core intervals; and axially shifting the displayed interval such that the correlation lines are generally horizontal.

14. A computer readable memory having recorded thereon statements and instructions for execution by a computer to carry out the method of any one of Claims 1 to 3.

15. The method of any one of Claims 1 to 3 comprising the further steps of:

a. selecting at least one region of the at least one digital image of the core sample to represent a shale type;

b. specifying colour threshold values for the shale type;
c. specifying shale volume calculation options; and d. calculating a shale volume value.

16. The method of any one of Claims 1, 2, 3 and 15 comprising the further steps of:
a. displaying the digital image of the core sample on the display device;

b. defining at least one facies by means of characteristics including facies colour and minimum and maximum shale volume value cut-offs, the facies colour and minimum and maximum shale volume value cut-offs being determined by reference to the digital image of the core sample;

c. selecting a facies interval directly from the digital image by selecting first and second locations representing top and base depths of the facies interval;

d. identifying the at least one facies with at least a part of the facies interval based on the characteristics;

e. displaying the at least one facies on the display device according to the top and base depths; and f. allowing for inspection and interpretation of the displayed at least one facies; and g. saving the displayed at least one facies and information concerning same.

17. The method of Claim 2 or 3 comprising the further step of using corrected top and base depths to annotate the at least one digital image.

18. A method of processing data for downhole core analysis comprising the steps of:
a. accessing electronic data comprising at least one digital image of a core sample from a well;

b. accessing well logging data corresponding to the core sample;
c. displaying the at least one digital image on a display device;

d. selecting a displayed interval from the displayed at least one digital image, the displayed interval being defined by a first depth and a second depth spaced from the first depth;

e. establishing an approximate actual depth value for the first depth of the displayed interval;

f. measuring the length of the displayed interval to determine an approximate actual depth value for the second depth of the displayed interval;

g. displaying the well logging data adjacent the displayed interval;

h. comparing the well logging data and the displayed interval to enable selecting corresponding depth markers on the displayed interval and the displayed well logging data, and to enable adjusting lost core intervals;

i. correcting the first depth and the second depth;

j. selecting at least one region of the at least one digital image of the core sample to represent a shale type;

k. specifying colour threshold values for the shale type;
l. specifying shale volume calculation options;

m. calculating a shale volume value;

n. defining at least one facies by means of characteristics including facies colour and minimum and maximum shale volume value cut-offs, the facies colour and minimum and maximum shale volume value cut-offs being determined by reference to the at least one digital image;

o. selecting a facies interval directly from the at least one digital image by selecting first and second locations representing top and base depths of the facies interval;

p. identifying the at least one facies with at least a part of the facies interval based on the characteristics;

q. displaying the at least one facies on the display device according to the top and base depths;

r. allowing for inspection and interpretation of the displayed at least one facies; and s. using corrected top and base depths to annotate the at least one digital image; and t. optionally saving the at least one digital image and information associated therewith.