Production Logging Analysis Tool PLATO Tutorial

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Production Logging Analysis Tool

PLATO Tutorial

Interpretive Software Products

www.ispforum.com

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Copyright Information

Interpretive Software Products claims copyright on each page of this document. The right to reproduce, distribute, display and make derivative works from this document, or any portion thereof requires approval from

Interpretive Software Products. For more information contact:

Interpretive Software Products

Web address: www.ispforum.com Email: [email protected] Document Author: Fred Vanhoecke Document Edition: 01 [September 2008]

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About This User Guide

Brief Description of the Chapters

This tutorial explains and describes a complete Well production analysis project, using simple examples and simplified data. The following Chapters are presented.

1 Introducing the PLATO Tutorial

This introductory Chapter gives an overview of the PLATO product.

2 Installing PLATO

This Chapter explains how to install the PLATO software.

3 Creating a Project

This Chapter explains how to create a new PLATO project.

4 Analysis of the Data

This chapter describes and explains a complete analysis consisting of a set of six Subtasks.

5 Zoning Techniques

This Chapter explains how to use the zoning techniques. Zoning means: using graphical tools to change parameters in specific sections of the Well.

User Profile

PLATO is not a black box program, but instead requires your interaction. To effectively use PLATO, it is assumed that:

 You have at least a basic understanding of production logs and their analysis.  You should be familiar with the operation of the various fluid identification

devices, what they record, and how they are used.

 You should also know the classical cross plot analysis of spinner data to determine the velocity of the fluid in the Well bore.

 You should be knowledgeable about logs to determine where fluid entries or exits are occurring along the Well bore.

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Highlighting Conventions

The following highlighting conventions are used in the text:

Bold Text

Used for highlighting any important text strings.

Light-grey Background and Italic Text

Used for Menu Items.

Bold-Italic Text

Used for Clickable buttons and icon names.

Italic Text

Used for Field, parameter and curve names. "Text in Quotation Marks"

Used for File names, entering text or values.

Clickable Icons

When used, an icon is shown in the margin of the document (see example in the margin). In the Graphical User Interface of PLATO, all icons are shown in the toolbar of the main window (MainPick). They are shortcuts to frequently used functions and tools. A list of all the icons and the equivalent menu item (if available), can be viewed in Section 1.3.3 Toolbar

Frequently Used Abbreviations

Abbreviation Description

PVT Pressure Volume Temperature

GOW Gas Oil Water

OW Oil Water

STP Surface Temperature and Pressure API American Petroleum Institute GOR Gas Oil Ratio

Show Context Help

Like most other software PLATO has small pop-up windows that show the name of a given button when the cursor moves across this button. More information can be shown in the pop-up windows by selecting Help-> Show context help in the menu. This extra information can, for example, be an explanation of the type of parameters that are assembled in a group in the Global editor.

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1 Introducing the PLATO Tutorial

This tutorial explains and describes a complete Well production analysis project, using simple examples and simplified data.

The goals of this tutorial are to introduce you to:  The Graphical User interface

 All the main features  How to set up a project

 The Six Analysis Subtasks (to be handled one-by-one and in sequence). This introductory Chapter gives an overview of the PLATO software application. The following main Sections are presented:

1.1 Overview of the Tasks ... 8 1.2 PLATO in a Nutshell ... 9 1.3 Overview of the Graphical User Interface ... 10

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1.1 Overview of the Tasks

Creating a Project

Analysis of the Data

Subtask 1: Reviewing the Input Data

 Edit the curve aliases.

 View the data.

Subtask 2: Preparing Data for Analysis

 Compute tool error estimates.

 Filter and average data logs. Subtask 3: Preparing the Spinner Data

 Compute the apparent velocity of the fluids from spinner data. Subtask 4: Building the Flow Profile

 Plan the global flow model. Subtask 5: Optimizing the Well Model

 Evaluate the data to determine the flow- and production rates. Subtask 6: Generating Surface Rates and Reports

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1.2 PLATO in a Nutshell

PLATO is a user-friendly, versatile and accurate tool for dramatically improving your Well production rates.

 PLATO is user-friendly, because: ▪ the workflow is easy to use.

▪ The computations are made in real-time • Guiding you through the workflow

• Using analyst-friendly graphical representations of the intermediate results.

 PLATO is versatile, because:

▪ All the available input data can be used simultaneously to compute the best flow profile.

▪ PLATO can determine production rates from flow meter data and/or temperature data.

▪ Furthermore, PLATO can analyse DTS data or simulate DTS data for feasibility studies.

You have the control over which logs to use. You can correct logs for depth, remove or add logs from the analysis and specify a weighting factor for each to improve coherence. The flow profile may be constrained in various ways to assess their impacts on the final analysis.

 PLATO is accurate, because:

▪ The analyzing process is based on the probabilistic optimization of a Well Model.

▪ In other words, the results are not found by using the classic deterministic method (requiring a drastic simplification of the occurring physics), but by optimizing a realistic Well Model.

Tool responses are predicted for each device under the conditions brought forth by the PLATO model. These predicted tool responses are compared to the actual data. Thereafter, the Well model is modified until the best possible match is obtained between the Well model and the actual data. The

coherence between the model and the data give direct quality control of the results.

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1.3 Overview of the Graphical User Interface

PLATO uses an analyst-friendly Graphical User Interface (GUI). The main window appears after setting up or re-opening a project.

From the main window, you can load and perform all the Subtasks provided by the application. The main window is also used to perform all editing and visualizations of parameters, log data and results.

The Main Window, shown below, contains the: 1. Caption bar 2. Menu bar 3. Toolbar 4. Canvas 5. Status bar 6. Picture buttons

1.3.1 Caption Bar

The Caption bar displays the following information in sequence, the:  Application name (e.g., "PLATO")

 Current Subtask (e.g., "PLATO-Process")  Current image (e.g., "MainPick")

 Project name (e.g., "SUMO")

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1.3.2 Menu Bar

The Menu bar contains all the tasks that can be performed by the PLATO application. The most common tasks are also available as shortcuts (icons and/or F-keys).

Tip Detailed explanations of the more complex tasks (e.g., editor and assist dialogs)

are available in the Alice Help. The Alice-Help file can be accessed by clicking the following menu item on your WINDOWSTM_desktop:

Start-> All Programs-> PLATO-> Help-> Alice Help.

The following tables contain all the menu and sub-menu items, including possible shortcuts.

Menu Item: File->

Shortcut Sub Menu 1 Sub Menu 2

Read parameter file Import log data Save

Save All

Save parameter file As Print...

Printer Preview...

Printer Options-> Printer Setup...

Print directly to printer Printer at true scale Exit

Menu Item: Edit->

Global editor Zone editor Curve editor F7 Image editor F8 Picture editor Report editor

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Menu Item: Tools->

Evaluation Global Optimization Next Subtask Sampling level Level1 (0.25%) Level 2 (0.50%) Level 3 (0.75%) Level 4 (0.75%) Level 5 (0.75%) Level 6 (0.75%) Level 7 (0.75%) Level 8 (0.75%) Level 9 (0.75%) Level 10 (0.75%) One in two (50%) All samples 100%)

Execution Modes High priority

Interactive

Subtask Idle (Review Data)

PreProcess (Prepare Data)

Spinner

Profile (Flow Profile)

Process (Optimizer)

PostProcess (Production Rates)

Task

Create a Report Report

Change database Change Well range

Change DB Units Delete DB Objects Create parameters

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Menu Item: Images->

F2 Main pick InputData-Pick SpinHist-Pick FlowProbe-Pick Constraints-Pick Pick1 Pick2 Pick3 Pick4 Pick5 Pick6 Plato-Idle-MainPick Plato-PreProcess-MainPick Plato-Spinner-MainPick Plato-Profile-MainPick Plato-Process-MainPick Plato-PostProcess-MainPick Default-Pick FluidProperties-Pick MultiRate-Pick F3 Other images

Menu Item: View->

Redraw screen

Show all pictures

Goto... First picture

Last picture

Previous picture page Next picture page Top depth Bottom depth Zoom In X 2 X 3 X 4 X 5

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Shortcut Sub Menu 1 Sub Menu 2 X 8 X 10 X 20 X 30 X 40 X 50 X 80 X 100 Other Zoom Out

View Options Enable scrolling

Cross hair

Automatic cross hair Large cross hair

Dark graphics background Dark grid lines

Verbose Legends

Edit viewpoints Add viewpoint

Remove all viewpoints Add hidepoint Remove all hidepoints

Edit Color gradients Gradient1

Gradient2 Gradient3 Gradient4 Gradient5 Gradient6

Graphics Tools Anchors

Figurines

Curve edit

Hard copy

Menu Item: Status->

Pause Continue Wrap up

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Terminate Show status View checkpoint Enable checkpoints

Edit checkpoints Add checkpoint

Remove all checkpoints

Menu Item: Options->

Ctrl move keys Scroll lock Auto advance Use Large Dialogs

No warning message Flashing Show Depth Marks

Use Smart Icons Picture Buttons to Right Hide Picture Buttons Novice User Mode Expert User Mode Use Help Wizard

Menu Item: Help->

Contents

Using Help Getting started

F11 Show context help

How to Glossary

Index About

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1.3.3 Toolbar

The following table lists all the clickable icons in the order they appear in the toolbar. They are shortcuts to functions and tools. The (available) alternative menu paths are shown next to the related icon.

Save - Saves all work done to time of save.

File-> Save

Exit - Terminates the program.

File-> Exit

Hard Copy - Creates a screenshot.

View-> Hard Copy

Global Editor - Opens the Global Editor.

Edit-> Global editor

Zoning Editor - Opens the Zoning Editor.

Edit-> Zone editor

Curve Editor - Opens the Curve Editor.

Edit-> Curve editor

Set Sampling Reduction Level - Allows the selection of a sampling percentage

Tools-> Sampling level

Evaluate - This “lightning bolt” icon begins the requested computation.

Tools-> Evaluate

Global Optimization - Used to optimize the flow calculation . Wrap Up - Finish Global Optimization as soon as possible.

Status-> Wrap up

Redraw Screen - Updates screen without initiating a new computation.

View-> Redraw screen

Rescale All Curves - (with Auto Scale set) - Rescales all the curves.

Zoom More - Zooms to magnify log view in steps along depth track.

View-> Zoom In

Zoom Less - Reduces log magnification in steps along depth track. Zoom Out - Returns magnified screen to normal size.

View-> Zoom Out

Top Of Page - Takes user to top depth.

View-> Goto...-> Top depth

Bottom Of Page - Takes user to bottom depth.

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Editing Depth Anchors - Opens the Depth Matching toolbox.

View-> Graphics Tools-> Anchors

Edit Figurines - Opens the Polygon Editing toolbox.

View-> Graphics Tools-> Figurines

Edit Curves With Mouse - Allows the editing of curves using the mouse.

View-> Graphics Tools-> Curve edit

Review Data (Subtask) - Starts/returns to the Reviewing the Input Data Subtask..

Tools-> Subtask-> Idle (Review Data)

Depth Matching - Allows curves to be depth matched. [No Menu Equivalent]

Prepare Data (Subtask) - Starts/returns to the Prepare Data for Analysis Subtask..

Tools-> Subtask-> PreProcess (Prepare Data)

Spinner (Subtask) - Starts/returns to the Preparing the Spinner Data Subtask.

Tools-> Subtask-> Spinner>

Flow Profile (Subtask) - Starts/returns to the Building the Flow Profile Subtask..

Tools-> Subtask-> Profile (Flow Profile)

Optimizer (Subtask) - Starts/returns to the Optimizing the Well Model Subtask..

Tools-> Subtask-> Process (Optimizer)

Production Rates (Subtask) - Starts/returns to the Generating Production Rates and Reports Subtask.

Tools-> Subtask-> PostProcess (Production Rates)>

Start the Wizard - Wizard helps the user through the then current step of the PLATO analysis.

Options-> Use Help Wizard

Help/Parameters & Curves - In the Help file, click Resources to access information.

Help->Glossary

Help/PLATO Concepts - Comprehensive index and computational details.

Help-> Contents

Select Spinner Xplot - Brings up spinner cross plot screen and Vap shift. [No Menu Equivalent]

Select Profile Editing View - Returns user to profile planning screen. [No Menu Equivalent]

Edit Fluid Properties - Opens Fluid Properties window in Global Editor. [No Menu Equivalent]

Show Error Log - Opens the Error Log. [No Menu Equivalent]

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1.3.4 Canvas

The Canvas is the area of the Main Window where the data is displayed graphically. When an Image is selected from the

Images- menu, its Pictures (plots or tracks) will be drawn on the canvas. The Canvas can contain two types of pictures:

 Tracks: The data is displayed in function of depth.

 Plots: The data is displayed in a histogram, a cross-plot or a station plot. When tracks are shown the depth axis is automatically added to the image. The layout of plots or tracks are calculated automatically, but you can change the relative width of a track.

The display area of a track or plot is divided in a Legend and the Drawing area. A right-mouse click in the Legend area will call up the Legend Editor. A double left-mouse click will perform automatic rescaling of the picture (provided Auto Scaling is enabled). The Drawing area can be Scrolled and, if required, Curve Editing can be performed.

1.3.5 Status Bar

The Status bar (below the canvas) shows information about the position of the cursor in the main window. The following information is displayed:

 When the cursor is within the canvas area, the current cross-hair reading is displayed.

 When the cursor hovers over an icon in the Toolbar, the function of the icon is displayed.

1.3.6 Picture Buttons

Each picture has an associated Picture button (green). The Picture buttons are shown to the right of the canvas area. Clicking a Picture button (down position) hides the associated picture. If the Picture button is clicked again (up position), the pictures is displayed again.

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2 Installing PLATO

To install a PLATO software package, simply follow the procedures in this Chapter. The following main Sections are presented:

2.1 Starting the Installation ... 20 2.2 Fast Installation ... 22 2.3 Completing the Installation ... 23

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2.1 Starting the Installation

To install the PLATO software, do the following:

1. Double click the "Setup.exe" file in the folder containing the files extracted from

the "Plato zip" file (an example PLATO folder is shown below).

2. The Install Wizard opens with the Customer Information dialog. Enter User Name

and Company Name. Click Next.

The Setup Type window opens as shown below.

Note Before you select the Setup Type, read the first paragraph of the next Section:

Choosing an Installation Type.

3. In the Setup Type window, select Fast installation and click Next. 4. Proceed to the next Section to continue the installation.

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2.2 Fast Installation

To proceed with the fast installation, do the following:

After clicking the Next button in the Setup Type window, the Unit System window opens.

1. In the Unit System window, select the default Unit System. 2. Click Next.

In the Check Setup Information window all settings are summarized (see the example window below).

3. Check the settings. If changes are required, return to previous dialogs by clicking

the Back button.

4. Click Next.

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2.3 Completing the Installation

To complete the installation, do the following:

1. After clicking the Next button in the Setup Information window, the installation of

the PLATO software starts. During the installation, a "Readme" file in HTML format opens (as shown in the example below). Read the information, and when done, close the "Readme" file.

An additional HTML file called "CrypKey" will open, explaining how to acquire a license (see the example below). Read the information, and when done, close the "CrypKey" file.

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2. Microsoft WORDTM will open. You will be prompted to enable macros and to install the Alice Macros. These macros must be installed in order to generate analysis reports.

3. Once the software installation is complete, click Finish and exit the wizard. 4. To complete the installation, reboot your computer.

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3 Creating a Project

In this Chapter, a new PLATO project will be created. The project and the database path will be specified. The input files will be selected and the basic Well

parameters will be set.

The following procedure explains how to create a PLATO project.

1. Click the PLATO icon in the WINDOWSTM menu: Start-> All Programs-> PLATO.

The Create new PLATO project dialog opens, as shown below.

2. In the Project Name field, enter the name of the new project, e.g., "3PhaseProd ".

The prepared example project is a three-phase producer. Therefore, "3PhaseProd" is an appropriate example name (Oil Water Gas).

3. Optionally, enter your name in the Analyst Name field.

4. Click Next to open the next dialog, as shown below.

Note The project name will be used as the project shortcut and default project folder

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In this dialog, you can change the project and database paths, the color coding and the unit system. However, in our example, there is no need to change anything.

5. Click Next to open the next dialog, as shown below.

6. Click the Add import files button to import ".LAS", ".LIS" or ".ASC" files of the

related project.

From the pop-up dialog (see below), any drive, folder and import files can be selected. In this example you will select ".LAS" files in the Plato/Ex2Gow folder.

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7. Select the first six ".LAS" files (Highlight the files and click Open). In this example,

you do not select files with suffix "S#"( stationary data).

8. The 'Add Import Files' window re-appears. The list of all the files that will be

imported can be viewed by clicking the down-arrow in the pull-down list.

9. Click Next to open the next dialog, which displays an overview of the project

settings.

10. You can view the input logs, their names and units by clicking the

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11. Click Next to open the next dialog.

12. The service company is selected. Selection of the service is used to preset log

names into the log aliases and preset tool characteristics. In this example the service company is "Baker atlas".

13. Click Next to open the next dialog, where a preselection of analysis types are

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14.

Note The three icons on each row have been added for user convenience to indicate a

Well location (land, desert and offshore).

15. In this example, you select Default PLATO, because you do not know yet which

phases will occur. Click the first icon (Land) of this option.

Caution In a real-case analysis, make sure you select the correct type. If you select the

wrong type, the analyzed results will be wrong.

16. Click Next to open the last dialog of the project creation procedure.

This last dialog displays a summary of the project settings. If required, you can change the settings by returning to previous dialogs.

17. Verify the information and click Finish to create the project.

This last step will create the log and parameter databases, and place them in the project folder. A project icon will be added as a shortcut, to re-open the project at any time.

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4 Analysis of the Data

The complete analysis consists of a set of six Subtasks. These Subtasks can be simple or complex, depending on the quality of the input data. The following is a brief description of each subtask.

Subtask 1: Reviewing the Input Data

In this Subtask, you inspect and sort the input data. You can remove logs if they are not recorded correctly. Make sure that all the available log data is displayed in the appropriate tracks.

Subtask 2: Preparing Data for Analysis

This Subtask is a preparation of the analysis to come. First you work with the fluid identification, pressure, and temperature logs. You select which logging runs will be put into the filtering process.

Subtask 3: Preparing the Spinner Data

In this Subtask, you use the spinner and line speed data to compute the apparent velocity (Vap) of the Wellbore fluid.

Subtask 4: Building the Flow Profile

This is the most important interactive phase! In this Subtask you build the

flow profile, based on the logs and the perforation locations. The flow profile is built by dividing/zoning the Well into intervals which are producing, thieving, flowing, or merely static.

Subtask 5: Optimizing the Well Model

In this Subtask, you optimize the Well model by generating the downhole flow and production rates of each fluid phase. This is an iteration process with the computation, first done in coarse depth increments, and then refined to include all of the data available.

Subtask 6: Generating the Production Rates and Reports

In this Subtask, you convert the downhole flow and entry profile to surface conditions. These are the production rates, which are the most important results of the analysis. Finally, you can generate a report containing all the inputs and the results.

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The following Sections are presented:

4.1 Subtask 1: Reviewing the Input Data ... 33 4.2 Subtask 2: Preparing Data for Analysis ... 36 4.3 Subtask 3: Preparing the Spinner Data ... 37 4.4 Subtask 4: Building the Flow Profile ... 39 4.5 Subtask 5: Optimizing the Well Model ... 42 4.6 Subtask 6: Generating the Production Rates and Reports ... 45

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4.1 Subtask 1: Reviewing the Input Data

In the first Subtask, the input data must be reviewed to make sure that all the imported data is present and can be accessed.

Once the project is created (see previous Section), the following screen is shown, displaying all the imported data as curves.

Initially, the tracks are displayed with default scaling. However, the scales can be too wide or the logs can partially/ totally fall out of the scale. In this example, we cannot see the Dielectric log, because it falls outside the default scaling.

To verify that all data is accessible and optimally displayed, do the following:

1. Automatically rescale all the curves by clicking the Rescale all curves icon.

Note It is good practice to rescale after an evaluation. The Rescale icon will be shown in

the margin, every time a re-scaling is required.

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On the right side of the screen, each track has an associated Picture Button (dark green). This button allows the user to hide (clicked down position) or show (not clicked position) the track.

2. Because there is no Gradio, GR, CCL and Caliper data, hide these tracks by clicking

the associated buttons (shown below).

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4.2 Subtask 2: Preparing Data for Analysis

In this Subtask, tool error estimates are calculated, the logs are filtered/smoothed, and multiple passes can be averaged.

To perform the Subtask Preparing the Data for Analysis, do the following:

1. Click the Prepare Data icon to start the data preparation Subtask.

2. Click the Evaluate icon to filter the tool curves and compute their error estimates.

3. Click the Rescale All Curves icon.

The following screen shows the updated tracks.

Basic color coding is as follows:

 Raw logs are always shown in their original default colors  Filtered (smoothed) logs are shown in black.

 Log error estimates (one standard deviation) are shown as dotted lines  Log error estimate derivatives with respect to depth are shown as pink lines.

4. In the example, all filtered curves are of good quality and, therefore, you do not

need any further editing or computations. Proceed to the next Subtask in the following Section.

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4.3 Subtask 3: Preparing the Spinner Data

In this Subtask the spinner and line-speed logs are used to calculate the apparent or bulk fluid velocity, Vap.

To perform the Subtask Preparing the Spinner Data, do the following:

1. Click the Spinner icon to start the spinner Subtask.

2. Click the Global Optimization icon to calibrate the spinner slope, spinner

threshold, and to start the iteration process to determine the most accurate Vap profile.

A best fit for Vap, Vthr and the Slope has been computed, as shown below.

4. Access the spinner/ linespeed crossplots by clicking the Spinner X-plot icon.

The left part of the screen shows the Spinner (RPS) vs. LineSpeed (FPM) crossplots at twelve depths, uniformly distributed across the interval to be analyzed. The red

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line and vertices correspond to the theoretical curves, calculated with Vap, Vthr and the Slope. The blue data points are the measured spinner responses.

The right part of the screen shows a plot of Spinner rotational speed (RPS) vs. the measured velocity of the flow relative to the spinner, Vcab -Vap (FPM), at each depth.

You can see that the computed line segments fit nicely through the measured data points.

5. The incoherence is low and the Vap is positive for up-flow. Therefore, proceed to

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4.4 Subtask 4: Building the Flow Profile

In this Subtask, you will build a tentative Production Profile by zoning the Profile parameter in the Profile track. The producing zones are identified by inspecting the curves (see the example screen in this Section). This screen displays many tracks, but three important tracks display clearly identifiable, sudden curve-angle changes. These sudden curve-angle changes are strong indications of fluid injection zones and, therefore, potential producing zones.

1. Click the Profile icon to start the profile building Subtask.

The screen below opens. You can see one blue track and several white tracks. The blue track is the track for marking the producing zones. It shows three curves that will help you to predict the flow profile, namely:

 D TwfDZ : The derivative of the temperature in function of depth.

 Vap : The apparent fluid velocity curve.

 DVapDz : The derivative of Vap in function of depth.

These curves show spikes at points of entry/ exit and, therefore, are potential producing zones..

The following three steps describe how to zone a producing zone. These steps are also illustrated in the following figure. It is recommended to start with the lowest zone.

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3. To designate a producing zone, place the cursor at the top or the bottom of the

zone, right -click-and-drag the cursor to the other boundary of the zone ( the width of the dashed marking-rectangle is irrelevant).

4. Release the button and the Profile Dialog opens. In this dialog the desired profile

specification is set and the boundaries of the zone can be changed.

5. Check Free hand zoning and select Produce.

6. Press OK. The selected square becomes green and the "Produce" label indicates a

producing zone.

More information about zoning of parameters can be found in Chapter 5.

7. When the lowest zone has been designated as producing, place the cursor

anywhere above this zone and call up the Profile dialog as before ( the dimensions of the selected interval are irrelevant here). Check Snap to top and bottom zones and select Flow.

8. Designate the other two zones as Produce by repeating steps 3 to 6.

9. When all three zones have been designated as producing, you have to specify the

Well and fluid information. This information is required to compute the quantitative flow profile. To enter this information click the

Fluid Properties Group icon.

10. The following list of parameters will appear. The information to be entered, for

this example, can be found in the file "Ex2GOW.txt".

11. Make sure the units are correct, before you provide the values. To modify a unit

right-click on the dark green label. This opens the Resource information dialog, where you can select the desired unit.

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12. When the information has been entered, click OK.

13. Click the Evaluate icon to build the Well model. The original screen is updated as

shown below. Notice that the potential producing zones have been added in the perforation track as blue blocks with a "rock" pattern.

14. Click the Rescale All Curves icon to get a balanced re-scaling of the tracks.

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4.5 Subtask 5: Optimizing the Well Model

You have reached the stage in the log evaluation process, where the fluid properties have been processed and the flow profile has been planned. In this Subtask, the production- and flow-rates of each phase remain to be estimated, based on these inputs.

To perform the Subtask Optimizing the Well Model, do the following:

1. To start the optimization process, click the Optimizer icon.

2. Click the Evaluate icon to optimize the holdups and compute the first global flow

model, shown below.

On this screen, you can see the downhole volumetric flowrates and the holdups along the Well for each phase.

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 Green for oil  Blue for water  Red for gas.

There are tracks for each measuring tool, displaying both their calculated (red) and measured (blue) curves. The incoherence between the model and the data is shown in the first track from the left.

The predicted and the measured curves show a good match in the top interval for all measuring tools. A good match is required, because the surface rates are known.

If there is not a good match, before proceeding, you need to determine which

tool or surface information is wrong.

Proceed with the Global Optimization, in which the rates will be optimized in all zones. In this procedure the Well model will be globally optimized (holdups and flowrates). The model is at first coarse, i.e. only a small amount of data points are used. A short computing time will be the result.

4. Click on the Global Optimization icon.

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6. If the incoherence is much higher than shown, you should do the following.

Return to the previous Subtask: Building the Flow Profile, call up the Well and fluid information dialog, set the ReZone Only parameter to "0" and repeat the Profile Building Subtask. Make sure that you specified the profile correctly, and, that you entered the correct fluid properties with the correct units.

7. Click the Set Sample Reduction Level icon and select All samples.

8. Click the Evaluate icon. At this point, all the data has been used.

The updated screen below shows the results of this Subtask.

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4.6 Subtask 6: Generating the Production Rates and

Reports

In this final Subtask, the production rates at surface conditions are calculated. To perform the Subtask Generating Surface Rates, do the following:

1. Click the Production Rates icon to start the last Subtask.

2. Click the Evaluate icon. The screen below opens showing the flowrates and

production rates for each phase at surface conditions.

3. Click the Rescale All Curves icon to get a balanced rescaling of the tracks.

In the three rightmost tracks, you can see the surface production rate for each phase in function of depth.

4. The lowest perforation produces only water. Therefore, you should recommend

to put a plug above 1175 ft.

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5 Zoning Techniques

Zoning is a simple and efficient way of marking and specifying parameters of a Well.

The zoning technique is the most frequently used method to: 1. Mark and specify fluid producing zones in a Well.

You use the mouse to roughly mark zones in a Well. Thereafter, you do the fine-tuning with the 'Zoning Profile' dialog (an example of a 'Zoning Profile' dialog is shown below).

This technique is explained in detail in this tutorial Chapter.

2. Add or remove passes for smoothing or spinner processing.

You use the 'Pass Selection' dialog to add or remove passes for smoothing or spinner processing (an example of a 'Pass Selection' dialog is shown below). 3. Specify different values for a given parameter along the Well.

You use the 'Value' dialog to specify different values for a given parameter along the Well (an example of a 'Value' dialog is shown below).

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The exercises in the following Sections can be made in less than fifteen minutes. However, to fully grasp the essence of the zoning and snapping methods, the exercises should be repeated a few times.

With this zoning technique, you use the mouse to graphically mark an area in a screen track, based on sudden changes in curve(s). Thereafter, you use the pop-up zoning dialog to further refine the specification of the curve(s)/parameter(s). The following Sections are presented. They describe and show the zoning options, using simple examples.

5.1 Marking a Producing Zone ... 49

5.2 Snapping To Top and Bottom ... 50

5.3 Specifying a Zone Exactly ... 51

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5.1 Marking a Producing Zone

A practical and simple example is used to show how the zoning technique works. The screen of the PLATO Tutorial, Subtask 4 is the basis for our zoning exercise. To get to the example screen, do the following:

1. Open the PLATO Tutorial example project by opening the following file in the Start

menu of WINDOWSTM:

Start-> PLATO-> 3PhaseProd.apf

2. Click the Flow Profile icon to go to the profile building.

In the "Flow profile" screen, the blue Profile track is now ready to be zoned. To mark a producing zone, do the following (refer also to the figures below):

3. In the blue Profile track, place the cursor approximately at the depth, where the

curve has a sudden change of angle (start of the injection zone).

4. Right-click-and-drag the cursor upwards to approximately the depth where the

curve has the next sudden change of angle (the width of the dashed marking rectangle is irrelevant).

5. Release the right mouse-button. The 'Zoning Profile' dialog opens.

In this dialog, you can specify the zoning option and Profile type.

6. Check the zoning option Free hand zoning in the bottom box. 7. Select the option Produce in the top box of the dialog. 8. Click OK.

9. The marked producing zone is shown in green. Verify if the green zone is labeled

as "Produce".

Congratulations, you just finished your first zoning exercise!

Step 1 and 2

Step 3 to 6

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5.2 Snapping To Top and Bottom

In the previous exercise Marking a Producing Zone, the result was a green producing zone. The area above this producing zone is marked as "Well Bottom". This is obviously not correct and must be changed to a flowing zone. You will use the Snap to top and bottom zone method to make this correction. The snapping technique makes it easy to change an area in one direction (up and/or down), without fiddling to get the correct depth with the cursor.

To use the Snap to top and bottom zone method, do the following:

1. In the blue Profile track, place the cursor approximately at the top of the green

producing zone.

2. Right-click-and-drag the cursor upwards anywhere in the blue zone, above the

producing zone. (the width of the dashed marking rectangle is irrelevant).

In this dialog, you can specify the zoning option and Profile type.

4. Check the zoning option Snap to top and bottom in the bottom box. 5. Select the option Flow in the top box of the dialog.

6. Click OK.

7. The zone above the producing zone is now a flowing zone, and as such labeled

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5.3 Specifying a Zone Exactly

In the previous Sections, we explained how to mark and snap a Well zone. These techniques are very fast, but not precise. In this Section, you are going to specify a zone exactly, using a zoning dialog.

To specify exactly, e.g., a producing zone, do the following:

1. In the blue Profile track, place the cursor approximately at the bottom of the

green producing zone, but still in the green area.

2. Right-click-and-drag the cursor upwards anywhere in the green zone (the width of

the dashed marking rectangle is irrelevant).

4. In the Top box, specify the top of the producing zone in foot, e.g., "11545" (ft). 5. In the Bottom box, specify the bottom of the producing zone in foot, e.g.,

"11595" (ft).

6. Click OK.

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5.4 Zoning Options

This Section gives a short description of all the graphical zoning options, using a dashed marking rectangle. Once a zone is marked, it can be specified precisely by entering the exact depths in the 'Zoning' dialog.

The zoning options are listed below:

 Snap to top zone: This option selects the marked interval plus the interval to

the next upwards zone boundary.

 Snap to bottom zone: This option selects the marked interval plus the interval

to the next downwards zone boundary.

 Snap to top & bottom zone: This option selects the marked interval plus the

intervals to the nearest zone boundaries above and below.  Free hand zoning: This option selects only the marked interval.  Clear all zones: This option removes all the zones.

 Clear all zones and free hand: This option selects only the marked interval.

The remainder is assigned the property of the highest zone.

Production Logging Analysis Tool PLATO Tutorial