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QAB 3023

ROCK PHYSICS & AVO ANALYSIS

ROKDOC (LAB 2 REPORT)

LECTURER : MR LULUAN

_____________________________________

NAME : RENUGA DEVI A/P SUBRAMANIAM

MATRIC : 16327

COURSE : PETROLEUM GEOSCIENCE

YEAR : YEAR 3 SEMESTER 2

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LAB 2.0 : PROJECT MANAGEMENT, IMPORTING DATA AND WELL VIEWER

OBJECTIVES

1. To understand global project setting.

2. To load and displaying data in the track.

3. To setup working interval

INTRODUCTION TO ROCK PHYSICS AND ROKDOC

Rock Physics is a key component in oil and gas explopration, development and

production. It provides the empirical relationships, understanding and theory to connect

petrophysical, geomechanical and seismic data to the intrinsic properties of rocks, such

as mineralogy, porosity, pore shapes, pore fluids, pore pressures, stresses and overall

architecture, such as laminations and fractures. Rock physics is needed to optimize all

imaging and reservoir characterization solutions based on geophysical data and to build

mechanical earth models for solving geomechanical problems.

RokDoc is defined as Quantitative Exploration and Development. It is a

comprehensive Quantitative Interpretation (QI) platform. It is designed to be powerful

and easy to use and is the number one QI platform of choice at oil companies worldwide

(Survey Aupec, 2012). RokDoc gives interpreters access to rock physics, forward

modelling, seismic inversion, geopressure, advanced quantitative reservoir analysis and

geomechanics. Besides, it enables asset teams to maximise the value of available data

and regional knowledge.

RokDoc has all the tools for forward modelling and rock physics analysis to link

well data to seismic data and relate rock properties to exploration data. Forward

modelling is a powerful what if? tool to predict the change in seismic signature related

to bed thickening or thinning, changes in rock properties such as porosity or

permeability, fluid changes and tuning effects that can interfere with direct rock and

fluid property identification. Rock physics drives a scientific understanding of a rocks

elastic property variations due to rock type changes, fluids, depth, temperature and

pressure.

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4. Confirm the value for Well KB(Kelly Bushing)=25.0, Well X Pos=300000and Well Y

Pos=6 000 000

5. Click Select Z-stick of Logs and choose MD then click coordinate unit and

selectfeet (ft)as the unit.

6. Click Create new well button.

7. Click Well management>Edit wells.

8. Change the colour of your choice by clicking colour block and definegas wellin

Show Type column. Select Completedas Completion status and click OK.

9. To load markers, right click Markers under demo wall in the project tree and

click Edit markers.

10.Click Import ASCII.. button and locate Test_Well_Tops.txt. Select appropriate

parameters and click Read button. Activate all.

11.Repeat the same process to load Position set.

12.Create new position set, rename it as you wish, highlight and Read ASCII file..

13.Select MD-Dip-Azimuth for position. Browse Deviation.txt(make sure the initial

value in the txt is 0 for both Depth and Deviation) and fill parameter

appropriately. (Use ft for unit and click Read when ready. Click active

checkbox. Specify that X,Y coordinate in the file are Relative and click No for

MD-TVD conversion.

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Question 1. Base-map before and after deviation well loaded. Print-out table of well

deviation converted from Dip-Azimuth to X-Y.

Figure 1: Well before deviation

Figure 2: Table of well deviation converted from Dip-Azimuth to X-Y and

Well after deviation

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Setting Up Of Porosity Log by Density

1.In the well viewer, select Well Ops > Petrophysics > Porosity by Density

Generator.

2.

Select GR as the source log and calculate.

3.Overlay the porosity log onto the GR log.

Question 2. Display of Tops and Bottoms sand-shale packages and display working

area.

Figure 3: Display of Tops and Bottoms sand-shale packages and display working area

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Question 3. Display of porosity log overlying with gamma ray and fill-sands area

then give your name on the track.

Figure 4: Display of porosity log overlying with gamma ray and fill-sands area

DISCUSSION

It is important to set cutoff in order to differentiate between sand and shale in GR track.

Based on figure 4, it is concluded that the green portion is clean sand where the GR is

less than 70 API while the purple portion is shale where the GR is more than 70 API. The

markers indicate the interval between the formations.

Clean Sand

Shale

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CONCLUSION

As mentioned earlier, RokDoc allows users to improve the quality and productivity of

subsurface analysis, accelerate value and reduce risk, save interpretation time by having

available tools needed to make right choices and achieve swift answers.

In summary, Lab 2 has 3 main work flows which are project management,

importing data and well viewer. In project management, there are four important data,

which are working intervals, averages, minerals sets and fluids sets. These data are

project level data. Moving on from that, Workflow 2 explains the procedures for

importing well data. It consists of six steps; LAS loading, log data, markers, position sets,

deviation surveys and checkshots. Lastly, we have seen Workflow 3 Well Viewer based

on these five steps; launching the well viewer, general right-click options, color fills,

working intervals and creating and using well views.

The results obtained are the base map of well before and after deviation is

generated. The table of well deviation converted from Dip-Azimuth to X-Y is also

obtained from the workflow. Next, display of tops and bottoms sand-shale packages and

working area are created. Lastly, the porosity log overlying with gamma ray and fill-

sands area is displayed. In the log, shale and clean zone is identified.

REFERENCES

EREX, 2011. RokDoc. Earth Resources Exploration

Ghosh, D.P. et al., 2013. Rock Physics Lab Manual. Department Of Geosciences, Universiti

Teknologi Petronas.

IkonScience, 2014. RokDoc. Retrieved from http://www.ikonscience.com/rokdoc-

software

Rock Physics, n.d. Retrieved from http://www.rockphysicists.org/