L&TD

WellCAD is a single well-oriented system that operates under Win32, the 32 bits application-programming interface (API) from Microsoft.

WellCAD runs on Windows 3.1x, Windows 95, Windows NT and DEC Alpha AXP running Windows NT. WellCAD is OLE2 compliant and supports OLE object linking and embedding, OLE automation and drag and drop between WellCAD documents and other OLE compliant software.

Windows compatibility

Compatibility with Windows means that WellCAD printing and plotting is virtually hardware independent. Data exchange between WellCAD

and other data sources and repositories is extremely flexible using industry standard file formats and using the Windows clipboard and OLE functionality

WellCAD data types

WellCAD is capable of handling a diverse range of borehole information all on one document. These data types include:

• Conventional single curve well logs e.g natural gamma and density curves
  
• Full waveform sonic logs with wiggle, black and white and full colour VDL presentation    
  
• Image logs (FMS, televiewer, multi-am caplier)
• Structure logs(sine wave and arrow plots)
• Lithological logs with and without bed boundaries
  
• Comment full text logs. Mud logs (uneven depth sampled or time based data)
• Well construction and down-hole equipment logs
• OLE logs (containing embedded or linked objects from other applications) 

WellCAD Features

•  Windows 95 graphical user interface
• Multiple document interface
• Fully mouse driven
• Windows clipboard data exchange facilities
• Multiple log file import and export facilities
• Full log editing facilities
• WYSIWYG display and print preview
• OLE automation
• OLE drag and drop
• Global depth shift function
• Document templates
• Worksheet customization

WellCAD tools:

•  Header Editor - with independent zoom and rotation
• Formula Parser - with dynamic data link and formula browser
• Depth Matcher -for differentially squeezing and stretching logs
• Image and Structure Log Processing Module -for image log processing and interactive structure interpretation
• Tabular Editor - with dynamic data link

Application in L & TD – VSP.

WellCAD is powerful software and has been used for multi-purpose in L & TD. Since 1996 it has often been used for casing inspection quick look analysis plots. 

This picture presents a casing inspecting result in White Tiger oil field .

DESCRIPTION

The Data Processing Software for the Sondex Multi-Finger Imaging Tool (MITpro software) performs the task of processing MIT raw data automatically, but under interactive user control. It reduces the tedium of manually   analysing   the   data, producing consistent, reliable reports showing where and to what degree the pipe wall is damaged or scaled.

The software locates

collars in tubing or casing, using a range of specialised, automatic search algorithms. The results can be modified interactively, until a suitable description of every joint is obtained.

To process the data, the software uses algorithms, which correct for tool decentring and fit the interior shape of the pipe locally. All deviations from the fitted shape are merged and classified into damage reports. The software configuration can be adapted to process the data from any type of survey, using any Sondex MIT tool.

MITpro can generate highly reliable and consistent survey reports, which are stored as

ASCII format disc files. These include Summary Report Files, which summarise the findings as a Joint Tabulation, and Process Report Files, which contain detailed damage information.

The Summary Report can be printed out, to a high presentation standard, suitable for offering to end-users directly. Worst-case cross section plots can be generated and appended to the report automatically. Both metric and imperial formats are supported throughout.

The MITpro software is a 32-bit application, which runs under Microsoft Windows 95 or Windows 98. The software can also run under Windows NT.

Some pictures below were taken from the casing and tubing inspection results.  Data source was recorded by MIT (24,40,60) tools in White Tiger oil field.

• In this case, the casing was strongly deformed

• This image illustrates that the casing was parted.The measured value from all of fingers exceed the nominal outer radius of the casing

• Solid material adhering to the inside of pipe

DESCRIPTION

          One of the most effective ways of understanding the condition of a well is to produce 3D images. To achieve this, we use a package called MITview

           MITview users are able to produce a CD for their customer with the data  fil  e  s of a particular job together with an operating version of the program. This allows the engineer responsible for the well to run MITView and examine the data himself

           Exported images can be used to produce hard copy pictures suitable for use in written reports, for example the BOP shown on the right. 

•  A specific image of mandrel in tubing inspecting results

• This picture shows the scale build up phenomenon in tubing and casing in a well

• MITView showing a casing, which was wom by drilling towhichol

Emeraude has been uesd in Vietsovpetro L&TD since 2000.

This is one of the best production log interpretation softwares, an impossibly missing tool of reservoir monitoring.

In recent years production logging has moved from being considered as the tool of last resort to a powerful quantitative method that takes its own place in the set of data acquisition tools for the reservoir engineer.

This has been due to two factors: the lowering of acquisition costs using 'fit‑for‑purpose' tools and shifting the interpretation into the hands of the end‑user engineer by the development of client as opposed to tool focused software; Emeraude.

In the past, PL was a highly specialized business. Data acquisition was made using expensive tools and interpretations were performed by engineers poring focused on the mechanical aspects of the tools and looking for specific well problems but not on the reservoir under study.

The realization of the value of the results of a production logging surveillance survey has given the reservoir engineer a powerful new tool in the drive for the more accurate and refined reservoir characterization.

All the major and most of the independent service companies as well as many operating companies now use Emeraude. Emeraude is seen as the industry standard allowing a common platform for communication and interpretation between service companies and the operators.

The latest version of Emeraude, Version 2.42, includes facilities for the interpretation of highly deviated to horizontal wells with specific processing for multiple‑probe tools. These include the generation of holdup/bubble images and the display of holdups inside a representation of the wellbore.

KAPPA remains committed to the ongoing development of the industry standard PL interpretation package, Emeraude.

Reference channels / Spinner calibration

An interpretation starts with the selection/definition of a Reference Channel for each available measurement. From the spinner passes ‑ if a spinner has been run ‑ the in‑situ calibration can be calculated on user selected calibration zones and a resulting apparent velocity channel is generated.

          PVT

The fluid type is defined, and the PVT properties of each phase are represented using a wide variety of Black‑Oil correlations, for bubble point or dew point fluids. Each correlation can be matched to a set of user entered constraint points, to ensure that the model values are representative.

          Zone Rates

When all the required information has been entered, the user defines a number of calculation zones, outside the assumed inflow zones. Based on the fluid types and the available measurements Emeraude suggest a list of possible flow models and, for the one retained by the user, the software automatically calculates the cumulative phase rates on all the calculation zones.

The rates are obtained using non‑linear regression, which makes it possible to supply any relevant set of inputs, and to possibly use redundant information. The solution rates are found by minimizing the error between measured and simulated values. Each difference (or residual) can be weighted separately. The following measurements are viable regression inputs: density, spinner apparent velocity, holdup of any phase, velocity of any phase, rate of any phase, mixture rate, mixture velocity, and temperature. The measurements may be continuous or stationary. The simulation is based on a full range of flow models from single‑phase to full 3‑phase situations, and a number of slippage correlations for those cases, in vertical or deviated wells. Specific models are also provided to handle flow re‑circulation (apparent down flow) as well as flow through a standing water/liquid column.

In the Zone Rates option, the backbone of the interpretation, all the results relevant to the calculation on any particular zone can be visualized such as the flow regime, the slippage velocities, holdups, the flow map for the selected correlation, etc. The model / correlations can be modified, the velocities can be changed manually, and the surface conditions can be matched. etc. The solution can be examined in terms of actual contributions (rather than cumulative).

Global Regression, solving simultaneously for all the contributions on the entire well, can be run if necessary. The Global regression can be used as a second path to impose constraints on the solution. Constraints can be individual sign constraints (producing zone or a thief zone). Contributions can be manually edited and/or fixed to a given value. This helps finding a coherent solution when standard methods fail.

The fractured basement reservoir is characterized by a very complex structure and it requires a special method to evaluate. BASROC is one of those. The software BASROC was developed by VSP in 1992, for application in reservoir evaluation and simulation for Bach Ho oil field. In order to increase the utility and accuracy in the determination of reservoir parameters, this software has been upgraded continuously. Version 3.0 is the latest version now used in evaluation and simulation of basement reservoirs in Bach Ho, Rong and other oil fields.

• Macrofracture zones characterized by macro-fracture systems, distributed directionally with hydrodynamic permeability.
• Microfracture zones distributed along surfaces of macrofractures.
  

1-Vug Porosity,

2 -Macro Fracture,

3- Micro Fracture, 4-Unchanged Rock.

BASROC is an advanced multi-mineral log analysis program. It computes the most probable formation mineralogy and total porosity, open porosity using a multi-log, least-squares inversion technique.

It is particularly valuable in areas of mixed lithologies, special minerals and two porosities systems.

Grade porosity by filtered method.

Calculate fracture porosity by looped technique.

Export the result in the tabular and bitmap files.

Any Microsoft Windows supported printing device.

Fig. 2 – The comparison of theoretically synthetic and practical curves

Fig. 3 – Results of BASROC processing for fractured Basement

Imager is an interactive image interpretation software package used to present and analyze vector data from the Circumferential Acoustic Scanning Tool (CAST), Electric Micro Imaging (EMI) tool, the Formation MicroScanner™ (FMS) tool, and the Fullbore Formation MicroImager (FMI) tool. Imager allows displaying the logged data graphically in various ways.

The images may be enhanced to emphasize certain features, facilitating the interactive calculation of dip and fracture information.

For CAST service, Using Imager, we can: 

• Display the amplitudes and travel times logged by the CAST in compressed, standard, and expanded scales.
• Simulate a three-dimensional view by projecting the two-dimensional view onto a smooth cylinder. The cylinder can then be rotated.
• Display the travel time information as a borehole cross section.
• Display statistical information about a particular image.
• Apply image enhancement algorithms (filters) to the CAST data.
• Calculate the dip angle and direction of any bedding features or fractures found.
• Change the color (indicating dip quality) for tadpoles.
• Save the bedding and fracture data to the CLS database file for later presentation.
• Save an enhanced image to the CLS database file for later presentation.

For EMI Service, using Imager, we can: 

• Display the electrical images of the borehole logged by the EMI tool in compressed, standard, and expanded scales.
• Simulate a three-dimensional view by projecting the two-dimensional view onto a smooth cylinder. The cylinder can then be rotated.
• Apply speed correction and pad height correction to the raw EMI data.
• Display statistical information about a particular image.
• Apply image enhancement algorithms (filters) to the EMI data.
• Calculate the dip angle and direction of any bedding features or fractures found.
• Change the color (indicating dip quality) for tadpoles.
• Save the bedding and fracture data to the CLS database file for later presentation.
• Save an enhanced image to the CLS database file for later presentation.

                  Calculate the dip angle and direction of bedding, fractures

Comparison of EMI Images with speed correction applied. 

Imager analysis program window    

Geometry and Stress analysis 

FULL WAVE SONIC tool measures compressional wave, shear wave and stoneley wave in a waveform.

*FullWave module. Using a fullwave module we can present and analyze fullwave acoustic data. The program allows displaying the logged data graphically in many ways. The data images can be enhanced to emphasize certain features.

The following analysis techniques are available with FullWave:

•  Frequency Display
•  Receivers Display
•  Delta-T for IRD
•  Stoneley Delta-T
•  Stoneley Reflector
•  LWD Delta-T, LWD Delta-T Lite, or LWD Delta-T Mark II

Beside that, FullWave module allows the use of Kaiser and Finite Impulse frequency filters and from that we can see and analyze compressional wave, shear wave or stoneley wave independently.

*RockXpertTM Analysis module. Critical Information for Fracture Designs and Well Plans

• Provides valuable input to fracture-design programs that predict fracture geometry and that help select fracturing fluids, proppants, and pumping schedules.
• Determines the mud weights required to prevent sanding and fracturing during drilling.
• Provides optimal direction in which to drill deviated, horizontal, and extended-reach wells to maximize borehole stability and increase the effectiveness of subsequent hydraulic fracturing
• Provides optimal direction in which to drill deviated, horizontal, and extended-reach wells to maximize borehole stability and increase the effectiveness of subsequent hydraulic fracturing
• Assists in evaluating a well’s sanding potential to determine whether a gravel pack or frac pack may be necessary to help maintain production at optimal levels

The declination of a horizontal wellbore with respect to the principal horizontal stress can have a significant effect on wellbore stability and fracture geometry. RockXpert logs can aid in well planning to minimize borehole instability and to maximize the effectiveness of fracturing operations.

At any specified point along a proposed or existing well path, RockXpert analysis can identify stable borehole conditions as a function of mud weight and borehole deviation.

RockXpert logs indicate the safe mud-weight range to provide sanding and formation breakdown, as shown in Track 2. The logs also include gamma and caliper curves in Track 1, predicted maximum borehole deviation in Track 3, and lithology information in Track 4.

STRES, FRACHT, FRACPAR, FWSIWC modules allow us to estimate:

•  Poisson’s ratio, Young’s module, bulk module, travel time ratio
• Max compressional phase, max shear phase, max Stoneley phase, max compressional frequency, max shear frequency, max Stoneley frequency.
• Transit time at: max compressional transmissivity, max shear transmissivity and max Stoneley transmissivity
• Fracture initial pressure, fracture closure pressure

This plot shows potential zones in White Tiger fractured basement by means of the energy loss of Stoneley wave (Track 5), in fact, these zones are highly productive

          The program has two basic options to evaluate these parameters:

·    The general case when any type of hydrocarbons may be present and hence the density of hydrocarbons is not known.

·    When density of hydrocarbons is known and there is little or no invasion. This option is primarily designed to evaluate tight gas sands where the density of gas is usually known and there is no invasion due to very low permeability.

Shale content is computed from one or several (as a minimum) of the following shale indicators: Gamma Ray, SP, Deep resistivity curve, Thorium, Potassium, Thorium+Potasium, Neutron, Density-Neutron cross plot, and Density-Acoustic cross plot; or an external shale volume Vsh is used for the volume of shale.  

Porosity is computed from the Density-Neutron cross plot or Density-Acoustic cross plot or single porosity logs: Density, Neutron or Acoustic. Salt and coal can be identified when necessary by setting flags and cut-off values. SASHA also corrects for the excavation effect (if desired).

Permeability can be computed from one of two equations: Timur or Wyllie-Rose. Effective permeabilities for hydrocarbons and water are also computed

Fig. 1 – Results of SASHA processing for Shaly Sand

       CORAL Analysis provides an accurate detailed description of reservoirs and mixed lithology. Its primary use is in the evaluation of formations, which contain shale, sand, limestone, dolomite, anhydrite, and gypsum. Minimum log data consists of a gamma ray or spontaneous potential log; a density, neutron, or sonic porosity log; and an induction or laterolog resistivity log. Improved results are obtained if photoelectric (Pe), shallow resistivity, sonic, dielectric, and spectral gamma ray data are used.    

        These logs will provide determination of shale content, cross plot lithology (sandstone-limestone or limestone-dolomite), anhydrite content, porosity, secondary porosity or gypsum (if an acoustic log is available), permeability and water saturation. If it is known that there is no limestone in a formation, the combination of sandstone-dolomite can be evaluated.
        Shale content can be computed from a number of shale indicators: Gamma Ray, SP, Deep resistivity curve, Thorium, Potassium, Gamma ray Thorium+Potasium, Neutron, Alternative Indicator, External Shale Volume, Density-Neutron cross plot, and Density-Acoustic cross plot. Several of these shale indicators can be used simultaneously, and then the minimum shale content of several shale volumes will be computed.
        Matrix densities of major minerals (sand, lime, dolomite, and anhydrite) can be changed within certain limits if necessary when solving density-neutron cross plot for lithology and porosity. Correction for gas can be done if density of gas is known. Salt and coal contents can be identified by setting the appropriate flags. There are options to compute porosity from single porosity logs (Density, Neutron or Acoustic) Several equations are included to compute water saturation: Archie. Simandoux, Indonesia, Waxman-Smits, and Dielectric analysis models.   Permeability can be computed from one of two equations: Timur or Wyllie-Rose. Effective permeabilities for hydrocarbons and water can be computed from one of the three equations: Park Jones, Boatman, or Pirson.

This program has been used popularly in L&TD for sedimentary rock evaluation.

Tool response equations available are SP, GR, Rt, Rxo, density, neutron and sonic.

Figure 1 shows the result of a CORAL processing for Shaly Sand-Lime-Dolomite with coal. The unknowns are porosity, clay volume, sand volume, water saturation, water saturation in flushed zone, hydrocarbon density, lime volume, dolomite volume, coal volume, and permeability index.

Fig. 1 – Results of CORAL processing for Shaly Sand-Lime-Dolomite with Coal

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        This is a weighted-least-squares error minimization technique which provides the analyst extensive flexibility to choose parameters, log measurements, and interpretive models. The affects of trace minerals, such as pyrite or ankerite, can be accurately evaluated with the ULTRA program. The analyst can also incorporate core results and other petrophysical data into ULTRA analysis to enhance the interpretation.

        Tool response equations are available for the following: SP, Gamma Ray, Natural Spectroscopy Gamma Ray, Bulk Density, Photoelectric, Sidewall Neutron, Sonic Log, Pulsed Neutron/TMD/Neutron Lifetime, Dielectric Constant/EPT.

       The following Log Analysis Models are built in: Shaly Sand, Sand-Lime-Dolomite with up to six other minerals and clay, Sand-Lime-Dolomite with up to six other minerals and shale represented as a mixture of clay and silt, Lime-Dolomite with up to six additional minerals and clay, Igneous and metamorphic reservoir model. Core data are used quantitatively in the minimization process.

      Fracture and secondary porosity may be determined in one of two possible ways:

• As the difference of porosity from the sonic log and the porosity from the weighted least squares error optimization process.

• From the cementation factor which can be declared to be unknown and computed at each level along with all other unknowns in the weighted least squares error minimization process.

• Easy to use
• Flexible
• Powerful
• Intelligent

Adaptable – for operation on a variety of systems, including but not limited to Vax, HP, IBM and Apollo

This program has been popular in L&TD for sedimentary and basement rock evaluation.

Figures 1 & 2 show results of ULTRA processing for two sedimentary models. The Sand-Lime-Dolomite with other mineral and clay (Fig.1) and Shaly Sand with another minerals (Fig.2) had been chosen for use with porosity, clay volume, sand volume, water saturation, flushed zone saturation, hydrocarbon density, lime volume, dolomite volume and another mineral volumes as the unknowns.

Figure 3 shows a result of ULTRA processing for a basement model. The unknowns are porosity, quartz volume, kali-feldspar volume, plagioclase volume, and another mineral volume.

Fig. 1 – Results of ULTRA processing for sedimentary rock

Fig. 2 – Results of ULTRA processing for Shaly Sand with another minerals

Fig. 3 – Results of ULTRA processing for Basement