Yasir_Corrected Copy (Recovered)

8/16/2019 Yasir_Corrected Copy (Recovered)

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2D Seismic Refection DataInterpretation o Meyal Area along

with 1D Forward Modeling,Petrophysics and Seismic Attri !teAnalysis

By

Muhammad Yasir

Msc Geophysics

2014-2016

Department of Earth Sciences

Quaid-i- !am "ni#ersity

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$s%ama&ad

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'E()$*$' )E

This dissertation submitted by Muhammad Yasir son of Muhammad yoo& is accepted in its

present form by the Department of Earth Sciences, Quaid-i-Azam University s!amabad as

satisfyin" the re#uirement for the a$ard of %&Sc& de"ree in 'eophysics&

(ecommended )y

Dr& %uhammad To#eer *********************

+Supervisor

Dr& %ona isa ****************

.hairperson Department of Earth Sciences

E/terna! E/aminer ******************

Department of Earth Sciences Quaid-i-Azam University s!amabad, 0a istan


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'+, ./EDGEME,)

am especia!!y than fu! to my dissertation supervisor Dr Muhammad )o eer that he a!$ays

"ave me his !ovin" "uidance $henever as ed and spared his precious time for me durin" my

$or &

am a!so than fu! to my senior 3eeshan Ahmed for he!pin" me in my pro4ect&

A!so specia!!y than s to my c!ass fe!!o$s +Aamir %ehboob, Umair Sa44ad, %a hzan 5hitran,

Sohai! %ehboob, Asad 3aman, 6ahim Shai h, %una$ar 0ervaiz, Shahab An$ar, 7oman Abdu!

%a4eed, )i!a! Shehzad, Tahir %ustafa &

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Specia% )han s

am especia!!y than fu! to my respected senior 3unaid &&asi $ho a!$ays he!ps us to so!vin"

the prob!ems faced durin" the pro4ect&

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DED$' )$ ,

dedicate my thesis to my 6ather, %other, )rothers and my Sisters $ho supported me a!$ays in

the difficu!t time a!so especia!!y than fu! to my e!der brothers $ho encoura"ed me for

comp!etin" my de"ree&

:


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&stract

The present study inc!udes structura! and strati"raphic interpretation attributes ana!ysis, one

dimensiona! for$ard mode!in" and the petrophysica! study& The data used for this study consistsof seismic data and $e!! !o"s data of %eya! area provided by the Department of Earth Sciences

Quaid-i-Azam University s!amabad& %eya! area !ies in the eastern 0ot$ar are no$n for its

hydrocarbon +oi! and "as structura! traps&

The Seismic !ines $ere ac#uired and processed by 0; & 6or interpretation of these seismic !ines

three ref!ectors and reverse fau!ts $ere mar ed by usin" the interactive too!s of 5in"dom

soft$are& n this $ay time section $ere obtained& After time to depth conversion the true

structura! "eometry $as obtained in the form of depth sections& The mar ed horizons $ereidentified usin" formation tops from $e!!s and their depths $ere confirmed throu"h

corre!ation $ith synthetic seismo"ram& After "eneratin" fau!t po!y"ons time "rids and depth

"rids of mar ed horizons $ere prepared& 6rom time and depth "rids time and depth contour

maps of the horizons of interest $ere "enerated to understand the spatia! "eometry of the

structures and the nature of "eo!o"ica! structures& (everse fau!tin" as identified on seismic

sections confirmed compressiona! tectonic re"ime in the study area resu!tin" due to ndian

Eurasian p!ate and %eya!-=> confirmed

the position and depth of the mar ed horizons&

The 0etrophysica! ana!ysis of %eya!-1 for the se!ected zones of the interest sho$ed reservoir

#ua!ity of different formations&

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Contents

1 ntroduction&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&1 ntroduction to Study area&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&2 ocation of Study Area&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1& Seismic (ef!ection Data&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&8 )ase %ap&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&9 Data 6ormats&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&9&1 SE'-@&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&9&2 AS 6i!e&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&9& 7avi"ation Data&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&: or 6!o$ Ana!ysis&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

1&? ;b4ectives&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2 'eo!o"y and Tectonics of Study Area&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&1 (e"iona! Settin"s and Tectonics&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&2 7orth$ard Drift of ndia and the ;penin" of ndian ;cean&&&&&&&&&&&&&&&&&&&&&&&&

2& Tectonic 3ones of 0a istan&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&8 Sedimentary )asins&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&8&1 ndus )asin&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&8&2 Upper ndus )asin&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&2&9 0ot$ar Sub basin&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&9&1 7orther 0ot$ar Deformed 3one +70D3 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

2&9&2 %a4or 6au!ts in 0ot$ar )asin&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Strati"raphy and 0etro!eum 'eo!o"y&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

&1 ntroduction&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

&2 ntroduction to the 0etro!eum 'eo!o"y of Area&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

& 0etro!eum 'eo!o"y&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

& &1 Structure&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

&8 Cydrocarbon 0otentia!&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

&8&1 (eservoir (oc &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

&8&2 Source (oc &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

&8& .ap (oc s&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

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8 Seismic nterpretation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&1 ntroduction&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&2 Seismic Data nterpretation Techni#ues&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&2&1 Strati"raphic Ana!ysis&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&2&2 Structura! Ana!ysis&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8& 1-D 6or$ard Seismic %ode!in"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8& &1 Synthetic Seimo"ram of %eya!-=>&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8& &2 ;ne Dimensiona! 6or$ard %ode! of e!! %eya!-=>&&&&&&&&&&&&&&&&&&&&&&&&

8&8 Time section of ine B?-%@ -=2&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&9 Time Section of ine B?-%@ -=?&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&: Time section of ine B?- %@ -=B&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&? Time Section of B?-%@ -12&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&> Time Section of B?-%@ -1 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&B 6au!t 0o!y"on 'eneration&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&B&1 6au!t 0o!y"ons .onstructed at The eve! of .hor"a!i 6ormation&&&&&&&&&&&&&&&&&&

8&B&2 6au!t 0o!y"ons .onstructed at the eve! of Sa esar 6ormation&&&&&&&&&&&&&&&&&&

8&1= .ontour %aps&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&1=&1 Time .ontour %ap of .hor"a!i 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&1=&2 Time .ontour %ap of Sa esar 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&8&1=& Time .ontour %aps of 7amma! 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&11 Depth .ontours&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&11&1 Depth .ontour %ap of .hor"a!i 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

8&11&2 Depth .ontour %ap of Sa ear 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

9 Seismic Attributes&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

9&1 Seismic Attributes&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

9&2 App!ications of Seismic Attributes&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

9& Types of Attributes&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

9& &1 'eometrica! attributes&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

9& &2 0hysica! Attributes&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

: 0etrophysics&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&1 ntroduction&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

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:&2 Types of o"s&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2&1 'amma (ay o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2&2 Spontaneous 0otentia! o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2& .a!iper o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2&8 (esistivity o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2&9 Sonic o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2&: Density o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&2&? 7eutron o"&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:& 0etrophysica! 0roperties of %eya! e!!-1 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

:&8 nterpretation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

.onc!usion&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

)ib!io"raphy&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

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/ist of *i ures6i"ure 1-1 (e"iona! map sho$in" !ocation of the %eya! 6ie!d and tectonic features associated$ith 7orthern 0a istan +Casany, et a!&, 2=12 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 1-2 'eo!o"ica! ocation of Study Area $ith %eya! )!oc Ci"h!i"hted +A&C&5azmi, et a!&,1BB2 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 1- )ase %ap of Study Area&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 1-8 or 6!o$ Ana!ysis&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 2-1 7orth$ard Drift of ndian 0!ate +7a#vi, 2==9 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 2-2 Tectonic %ap of 0a istan +A&C&5azmi, et a!&, 1BB2 &&&&&&&&&&&&&&&&&&&&&&&&6i"ure 2- Tectonic Division of 0ot$ar )asin +Casany, et a!&, 2=12 &&&&&&&&&&&&&&&&&&&&&&&&6i"ure 2-8 'enera!ized Strati"raphy of 0ot$ar Sub-)asin Schematic +%u"ha!, et a!&, 2==? &&&&&&296i"ure -1 Strati"raphic .o!umn of 0ot$ar (e"ion +Casany, et a!&, 2=12 &&&&&&&&&&&&&&&&&&&&&&6i"ure -2 Sho$s the oi! and "as fie!ds of 0ot$ar 0!ateau +Shah, 1B?? &&&&&&&&&&&&&&&&&&&&&&6i"ure 9-9 Synthetic Seismo"ram of %eya!-=>&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

6i"ure 9-: ;ne- Dimensiona! 6or$ard %ode! of %eya! =>&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-1 Time Section of B?-%@ -=2&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-2 Time Section of ine B?-%@ -=?&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8- Time Section of ine B?-%@ -=B&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-8 Time Section of B?-%@ -12&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-9 Time Section of B?-%@ -1 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-: 6au!t 0o!y"ons .onstructed at the eve! of .hor"a!i 6ormation&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-? 6au!t 0o!y"ons 'enerated at the eve! of Sa esar 6ormation&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-> Time .ontour %ap of .hor"a!i 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-B Time .ontour %ap of Sa esar 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

6i"ure 8-1= Time .ontour %ap of 7amma! 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-11 Depth .ontour %ap of .hor"a!i 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 8-12 Depth .ontour %ap of Sa esar 6ormation&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 9-1 Enve!ope of ine B?-%@ -=2&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 9-2 Avera"e Ener"y of ine B?-%@ -=2&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 9- 0hase Attributes of ine B?-%@ -=2&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure 9-8 nstantaneous 0hase 6re#uency of ine B?-%@ -=2&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure :-1 o" curve sho$in" the response of different !o"s and the ca!cu!ated sh in %eya!

e!!-1 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&6i"ure :-2 o" curve sho$in" the ater saturation +S$ , Cydrocarbon saturation +Sh , )u!

o!ume, and estimated 0ermeb!ity in the !o$er part of the urassic Se#uence %eya! e!!-1 &&&&:1

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"hapter 1

1 $ntroduction

1 1 $ntroduction to Study area

%eya! 6ie!d is !ocated in Attoc district, near 0indi 'heb, 11= i!ometers south$est of

s!amabad in an active fore!and and thrust be!t in the .entra! 0ot$ar 0!ateau of the Upper ndus

)asin& %eya! 6ie!d is one of the ma4or oi! and "as producin" fie!ds in the 0ot$ar 0!ateau& The

fie!d $as discovered by 0a istan ;i!fie!ds imited in 1B:>& Discovery resu!ted after 92 years of

continuous e/p!oration efforts in the %eya!-5harpa area& n 1B1:, soon after the discovery of

5haur 6ie!d, the first $e!! $as dri!!ed $hich $as terminated in the %o!asse se#uence $ithoutreachin" the Eocene +Casany, et a!&, 2=12 &

The %eya! 6ie!d has produced : %%); and 29= ).6 "as from three reservoirs& The bu! of

production has come from the fractured carbonates of the .hor"a!i-Sa esar formations of Eocene

a"e, $hereas mar"ina! production has a!so been obtained from the carbonates of 0a!eocene

(ani ot- oc hart formations and urassic Datta 6ormation sandstone& The dri!!in" activity $as

focused main!y at the centra! part of the Eocene reservoir& After the discovery, the fie!d $as

subse#uent!y deve!oped durin" 1B:> to 1BB? by dri!!in" 19 more $e!!s& E/cept $e!! 7o& 11, a!!

$e!!s reached their ob4ective depths and produced varyin" vo!umes of hydrocarbons& The

produced "as from Eocene reservoirs contained appro/imate!y 2F C2S $hich $as unfit for the

pipe!ine and for the refinery& A "as s$eetenin" p!ant and su!fur recovery p!ant $as erected in

1B?8 for the commercia! supp!y of "as& An 0' + i#uefied 0etro!eum 'as p!ant $as a!so

insta!!ed to e/tract the 0' from the producin" "as in 1B>2-> & The producin" capacity of this

p!ant is 2== metric tons 0' per day +Casany, et a!&, 2=12 &

1 2 /ocation of Study rea'eo"raphica!!y the study area is situated at a part of the 0oto$ar basin, $hich !ies in the northern

part of upper ndus basin& n the south of %eya! area there is 5a!ar 5har, in the east city of

.ha $a! and in $est city of Ta!a"an"& The area is no$ easi!y approachab!e due to construction

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of ahore s!amabad %otor$ay& The study area %eya! !ies bet$een !atitude G, 11H, ==I 7 to

G, 22H, ==I 7 and !on"itude ?1G, 9BH, ==I E to ?2G, 1>H, ==I E&

6i"ure 1-1 (e"iona! map sho$in" !ocation of the %eya! 6ie!d and tectonic features associated

$ith 7orthern 0a istan +Casany, et a!&, 2=12 &

'eo!o"ica!!y %eya! b!oc !ies in the northern part of 0ot$ar sho$n in $here the structura! trend

is northeast-south$est as compared $ith the dominant east-$est trend of northern 0ot$ar& The

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%eya! b!oc !ies in the northern part of 0ot$ar sub-basin i&e& 70D3& The ndus (iver and the

he!um and Soan rivers are passin" on its $estern and eastern sides respective!y& The 5a!achitta-

%ar"a!!a (an"es are in the north and the Sa!t (an"e is in the south& Since area is tectonica!!y

very comp!e/, that is $hy, seismic study of this area is very tou"h& There is hi"h concentration of

hydrocarbons in this area& Thrust re!ated structura! !i e pop up, dup!e/ and antic!ina! traps are

common in this area&

6i"ure 1-2 'eo!o"ica! ocation of Study Area $ith %eya! )!oc Ci"h!i"hted +5azmi, et a!&,

1BB2 &

1 5 Seismic (ef%ection Data

The seismic ref!ection data of the study area $as obtained by Directorate 'enera! of petro!eum

concession +D'0. 0a istan in di"ita! format &This data $as ac#uired and processed by 0; &

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The trend of the seismic dip and stri e !ines in SE-7 and S -7E respective!y& The seismic

ref!ection data are "iven be!o$J

1 4 Base Map

The base map is important component of interpretation, as it sho$s the spatia! position of each

pic et of seismic section& 6or a "eophysicist a )ase map is that $hich sho$s the orientations of

seismic !ines and specify points at $hich seismic data $ere ac#uired or simp!y a map $hichconsist of number of dip and stri e !ines on $hich seismic survey is bein" carried out & A base

map typica!!y inc!udes !ocation of !ease and concession boundaries, $e!!s, seismic survey points

and other cu!tura! data such as bui!din"s and roads $ith "eo"raphic reference such as !atitude

and !on"itude& 'eophysicist typica!!y use shot points maps, $hich sho$ the orientation of

seismic !ines and shot points at $hich seismic data $ere re#uired , to disp!ay interpretation of

seismic data&

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6i"ure 1- )ase %ap of Study Area

1 Data *ormats

Seismic ref!ection data $hich consist of fo!!o$in" formatsJ

1 1 SEG-YThe SE' @ +sometimes SE'-@ fi!e format is one of severa! standards deve!oped by the Society

of E/p!oration 'eophysicists +SE' for storin" "eophysica! data& t is an open standard , and is

contro!!ed by the SE' Technica! Standards .ommittee, a non-profit or"anization&

The format $as ori"ina!!y deve!oped in 1B? to store sin"!e-!ine seismic ref!ection di"ita! data

on ma"netic tapes & The specification $as pub!ished in 1B?9&

The format and its name evo!ved from the SE' IE/I or E/chan"e Tape 6ormat& Co$ever, sinceits re!ease, there have been si"nificant advancements in "eophysica! data ac#uisition, such as -

dimensiona! seismic techni#ues and hi"h speed, hi"h capacity recordin"&

1:

https://en.wikipedia.org/wiki/File_formathttps://en.wikipedia.org/wiki/Society_of_Exploration_Geophysicistshttps://en.wikipedia.org/wiki/Society_of_Exploration_Geophysicistshttps://en.wikipedia.org/wiki/Geophysicshttps://en.wikipedia.org/wiki/Open_standardhttps://en.wikipedia.org/wiki/Open_standardhttps://en.wikipedia.org/wiki/Seismic_reflectionhttps://en.wikipedia.org/wiki/Magnetic_tapehttps://en.wikipedia.org/wiki/Seismichttps://en.wikipedia.org/wiki/File_formathttps://en.wikipedia.org/wiki/Society_of_Exploration_Geophysicistshttps://en.wikipedia.org/wiki/Society_of_Exploration_Geophysicistshttps://en.wikipedia.org/wiki/Geophysicshttps://en.wikipedia.org/wiki/Open_standardhttps://en.wikipedia.org/wiki/Seismic_reflectionhttps://en.wikipedia.org/wiki/Magnetic_tapehttps://en.wikipedia.org/wiki/Seismic


17/59

1 2 / S *i%eo" AS. Standard + AS is a standard fi!e-format common in the oi!-and-"as and $ater $e!!

industries to store $e!! !o" information& e!! !o""in" is used to investi"ate and characterize the

subsurface strati"raphy in a $e!!&

A sin"!e AS fi!e can on!y contain data for one $e!!, but it can contain any number datasets

+ca!!ed IcurvesI from that $e!!& .ommon curves found in a AS fi!e may inc!ude natura!

"amma , trave! time , or resistivity !o"s&

1 5 ,a#i ation Data 7avi"ation data actua!!y !ocate the area $here survey has been carried outJ it te!!s us about the

!ocation of that area on the "!obe& 'enera!!y navi"ation data is "iven in K, @ coordinates or in the

form of atitude and on"itudes by $hich $e can trace our area on the "!obe&

1 6 .or *%o7 na%ysis

The nterpretation $as carried for$ard usin" different techni#ues and steps $ith each step

invo!ve different processes $hich $ere performed usin" the soft$are too!s as mentioned above&

Simp!ified $or f!o$ used in the dissertation is "iven, $hich provides the comp!ete picture

depictin" ho$ the dissertation has been carried&

6i"ure 1-8 or 6!o$ Ana!ysis

1?

https://en.wikipedia.org/wiki/File_formathttps://en.wikipedia.org/wiki/File_formathttps://en.wikipedia.org/wiki/Petroleum_industryhttps://en.wikipedia.org/wiki/Water_wellhttps://en.wikipedia.org/wiki/Boreholehttps://en.wikipedia.org/wiki/Boreholehttps://en.wikipedia.org/wiki/Boreholehttps://en.wikipedia.org/wiki/Well_logginghttps://en.wikipedia.org/wiki/Well_logginghttps://en.wikipedia.org/wiki/Well_logginghttps://en.wikipedia.org/wiki/Stratigraphyhttps://en.wikipedia.org/wiki/Gamma_ray_logginghttps://en.wikipedia.org/wiki/Gamma_ray_logginghttps://en.wikipedia.org/wiki/Gamma_ray_logginghttps://en.wikipedia.org/wiki/Sonic_logginghttps://en.wikipedia.org/wiki/Resistivity_logginghttps://en.wikipedia.org/wiki/Resistivity_logginghttps://en.wikipedia.org/wiki/File_formathttps://en.wikipedia.org/wiki/Petroleum_industryhttps://en.wikipedia.org/wiki/Water_wellhttps://en.wikipedia.org/wiki/Boreholehttps://en.wikipedia.org/wiki/Well_logginghttps://en.wikipedia.org/wiki/Stratigraphyhttps://en.wikipedia.org/wiki/Gamma_ray_logginghttps://en.wikipedia.org/wiki/Gamma_ray_logginghttps://en.wikipedia.org/wiki/Sonic_logginghttps://en.wikipedia.org/wiki/Resistivity_logging


18/59

1 8 &9ecti#es

The main ob4ectives of this dissertation based on interpretation of seismic section areL

o Structura! and strati"raphic interpretation to find out the structura! traps and horizons of

interest&o Seismic attribute ana!ysis to confirm the interpretation&o 1 D for$ard mode!!in" to confirm the mar ed horizon &

o 0etrophysica! ana!ysis of reservoir formations to identify their prospect zones&

1>


19/59

"hapter 2

2 Geo%o y and )ectonics of Study rea

2 1 (e iona% Settin s and )ectonics

The Cima!ayan co!!ision system represents an active co!!ision oro"en bet$een the ndian and

Eurasian subcontinents& The co!!ision $as active since about 99 %a +5azmi, et a!&, 1BB2 and

invo!ves continuous up!iftin", erosion and deposition of sediments&

The 0ot$ar 0!ateau is situated in the !esser Cima!ayas of 0a istan, a zone of deformed meta-

sedimentary and sedimentary roc s ori"ina!!y deposited on the northern ndian continenta!

mar"in and in the ndo-'an"etic fore!and basin& This zone is south of the hi"h crysta!!ineCima!ayas, $hich contain, from north to south, meta-sedimentary and i"neous roc s of the

northern Asian continenta! mar"insJ meta-vo!canic, i"neous and meta-sedimentary roc s of the

5ohistan s!and arc terrainJ and i"neous and hi"h "rade metamorphic roc s of the intense!y

deformed northern mar"in of the ndian 0!ate& Thrust fau!ts have been traditiona!!y assi"ned for

the fau!t contacts bet$een these zones +5azmi, et a!&, 1BB2 &

Sedimentary strata in the fore!and are detached and trans!ated a!on" the Sa!t (an"e Thrust over

the ndo-'an"etic fore!and +'ee, 1B>B & The topo"raphica!!y ru""ed Sa!t (an"e and 0ot$ar

0!ateau is the northernmost feature of ndus )asin, bounded by the %ain )oundary Thrust and

the 5a!!a .hitta (an"e in the north and the Sa!t (an"e in the south +'ee, 1B>B & 0recambrian

Sa!t and possib!y Eocene evaporites and ar"i Cites are !i e!y the main deco!!ments that produced

!ar"e sca!e thrusts and te!escopin" that had transported the sedimentary units substantia!

distances from the point of their ori"in in the 0ot$ar and 5ohat basins&

Due to the e/istence of a number of $e!!-defined mappab!e surface antic!ines in the 5ohat-

0ot$ar )asin, hydrocarbon e/p!oration efforts remained active since 1>:= $hen the first $e!!

$as dri!!ed in 5unda! near %ian$a!i& These efforts $ere focused in the areas of oi! seeps&

The !ast period of up!ift and erosion corresponds to ma4or co!!ision probab!y durin" the ate

Eocene +Casany, et a!&, 2=12 & ;!i"ocene roc s are not present in the 0ot$ar re"ion $hich a!so

!ed us to assume that pro!ific structures $ere "oin" throu"h the process of fo!din" durin" that

time&

1B


20/59

2 2 ,orth7ard Drift of $ndia and the penin of $ndian cean

The ndo-0a istan subcontinent separated from the 'ond$ana mother!and about 1 = mi!!ionyears a"o +7a#vi, 2==9 &

6i"ure 2-9 7orth$ard Drift of ndian 0!ate +7a#vi, 2==9

2=


21/59

ts !ocation $ithin 'ond$ana in re!ation to Africa, Antarctica and Austra!ia is uncertain& arious

authors have p!aced in different positions& t has been estimated that bet$een 1 = m&y& and >=

m&y& ndia moved north$ard at a rate of to 9 cmMyear&

The vast distance +9,=== 5m bet$een the matchin" set of anoma!ies 21 and 2 sho$s that from>= m&y& a"o ndia moved at an avera"e rate of about 1: cmMyear re!ative to Austra!ia and

Antarctica )efore anoma!y 22 +9= m&y& this rate of movement varied bet$een 19 and 29

cmMyear&

This movement $as faci!itated by transform fau!tin" in the 0roto-;$en fracture zone and

e/tensive sea-f!oor spreadin" a!on" %id ;ceanic (id"e& t is note$orthy that e/tensive e/trusion

of Daccan Trap )asa!ts occurred bet$een :9-:= m&y& a"o durin" the fast north$ard drift of ndia&

2 5 )ectonic :ones of ;a istan

0a istan can be divided into seven tectonic zones, +5azmi, et a!&, 1BB2

o ndus 0!atform and 6ore deep&o East )a!ochistan 6o!d and Thrust )e!t&o 7orth$est Cima!ayan 6o!d and Thrust )e!t&o 5ohistan- ada h %a"matic Arc&o 5ara oram )!oc &o 5a ar 5horansan 6!ysch )asin and %a ran Accretionary 3one&o .ha"ai %a"matic Arc

2 4 Sedimentary Basins

)asin is an area that is characterized by re"iona! subsidence and in $hich sediments accumu!ate

and preserved for a "eo!o"ic time& 0a istan has three broad tectonic basins, ndus )asin,

0esha$ar )asin and )a!uchistan )asin&

2 4 1 $ndus Basinndus )asin consists of 29=== s#& 5m of South-East of 0a istan& t inc!udes the Thar-.ho!istan

desert and ndus 0!ain& Tectonica!!y it is much stab!e area as compare to other tectonic zone of

0a istan& t comprises of buried rid"es, p!atform s!ope, zone of up $arp and da$n $arp& +5azmi,

et a!&, 1BB2 , Structura!!y ndus )asin divided into t$o main partsJ

21


22/59

6i"ure 2- 6 Tectonic %ap of 0a istan +5azmi, et a!&, 1BB2 &

N Upper ndus )asin +in north

N o$er ndus )asin +in south

22


23/59

o$er ndus )asin is further divided into t$o partsJ

N .entra! ndus )asin +in north

N Southern ndus )asin +in south

2 4 2 "pper $ndus Basint is !ocated in the northern 0a istan and separated from the !o$er ndus )asin by the Sar"odha

Ci"h& %)T is in its north, $hi!e in east and $est stri e s!ip fau!ts he!um and 5a!aba"h is

!ocated& Upper ndus basin is subdivided into 0ot$ar and 5ohat )asins a!on" the ndus (iver&

+5azmi, et a!&, 1BB2 &

6i"ure 2-? Tectonic Division of 0ot$ar )asin +Casany, et a!&, 2=12

2 4 2 1 ;ot7ar Basin0ot$ar is a 6ore-!and fo!d and Thrust be!t of Cima!aya ;ro"eny that is bounded by 5a!a-.hitta

and %ar"a!!!a Ci!!s to the north, ndus (iver and 5ohat 0!ateau in the $est, he!um (iver and

Cazara 5ashmir Synta/is in the east and Sa!t (an"e 6ormation in the south& 0ot$ar 0!ateau has

undu!atin" topo"raphy& t is characterized by a series of para!!e! rid"es and va!!eys, "enera!!y

2


24/59

trend in the E- direction& 'eo!o"ica!!y, it forms part of the fore!and zone of the 7 Cima!ayan

6o!d and-Thrust be!t& Structura!!y 0ot$ar )asin is divided into 7orth 0ot$ar Deform 3one

+70D3 in the north, Soan Sync!ine and Southern 0ot$ar Deformed 3one +S0D3 in the south&

0ot$ar basin is covered by the mo!asse sediments ran"in" in a"e from %iocene to 0!eistocene&

0recambrian to Tertiary se#uence is e/posed a!on" the ran"es in south +Shami, et a!&, 1BB>

2 ;ot7ar Su& &asin

The 0ot$ar sub-basin is !ocated in the $estern foothi!!s of Cima!ayas in northern 0a istan& t

inc!udes the 0ot$ar 0!ateau, the Sa!t (an"e, and the he!um 0!ain& t is bounded in the north by

main )oundary Thrust-%)T +recent!y the term %)T has been cha!!en"ed by #ba! and )annert,

1BB> and #ba! et a!&, 2==? ho$ever $ithout indu!"in" in this controversy the term is used as

such in the te/t due to its common use in the !iterature and Sa!t (an"e in the south& he!um

stri e-s!ip fau!t occurs in the east and ndus (iver and 5a!aba"h stri e s!ip fau!t in the $est&

5ohat 0!ateau is in the $estern stri e e/tension of the 0ot$ar sub-basin $ith re!ative!y severe!y

deformed structures& The 0ot$ar sub-basin is fi!!ed $ith thic 0re-.ambrian evaporites over!ain

by re!ative!y thin p!atform deposits of .ambrian to Eocene a"e fo!!o$ed by thic %iocene

0!iocene mo!asse& This $ho!e section has been deformed by intensive Cima!ayan oro"eny in

0!iocene to %idd!e 0!eistocene& The 0ot$ar sub-basin is one of the o!dest oi! provinces of the

$or!d, $here the first commercia! discovery $as made in 1B18 at 5haur& So far, about 19=e/p!oratory $e!!s have been dri!!ed of $hich most cou!d not reach tar"et depths due to

operationa! prob!ems re!ated to e/treme!y hi"h-pressure $ater in mo!!asse deposits, thus $ere

premature!y abandoned& This abnorma! pressure is re!ated to rapid depositionMburia! of mo!asse

deposits, $hich is further a""ravated by structura! comp!e/ities& The centra!, $estern and the

eastern parts of the Sa!t (an"e M 0ot$ar 0!ateau have #uite different structura! sty!es& Uneven

distribution of sa!t, occurrence of different detachment !eve!s, fau!ts and f!e/ures in the basement

are amon" the possib!e reasons for structura! comp!e/ity& Subsurface picture of the 0ot$ar sub-

basin demonstrates that structures are re"iona!!y bounded by fore!and ver"in" thrusts& These

thrusts are "enera!!y trendin" northeast south$est in the eastern part, a!most east-$est in the

centra! part, and north$est-southeast in the $estern parts of the 0ot$ar sub-basin& There is !ess

distribution of evaporites in the eastern part $here competent roc s +carbonates and sandstones

dominate&

28


25/59

6i"ure 2-> 'enera!ized Strati"raphy of 0ot$ar Sub-)asin Schematic


26/59

+5ema!, 1BB1 ca!cu!ated about 99 m of horizonta! shortenin" for the zone bet$een the Soan

sync!ine and a point near %)T and the minimum rate of shortenin" in this zone is estimated to

be 1> mmMyr&The 70D3 is fo!!o$ed to the south by asymmetrica! $ide and broad Scan sync!ine,

$ith a "ent!y north$ard dippin" southern f!an a!on" the sa!t ran"e and a steep!y dippin"

northern !imb a!on" 70D3&

2 2 Ma9or *au%ts in ;ot7ar BasinAs 0ot$ar represents the southern mar"in of the Cima!ayan co!!isiona! zone, a variety of fau!ts

and fo!ds e/ist in this area& Some of the ma4or fau!ts of the area are "iven asL

o 5hair-i-%urat 6au!t +5%6

o Sa h$a! 6au!t +S6

o 5anet 6au!t +56

o Dhurna! )ac Thrust +D)T

o %ian$a!a 6au!t +%6

o (i$at 6au!t +(6

%a4or 6o!ds in 0ot$ar )asin

)esides ma4or fau!ts, other structures present in the area inc!ude severa! antic!ina! andsync!ina!

features $hich are "iven as fo!!o$sL

o Soan Sync!ineo .ha 7auran" Antic!ineo Adhi-'un"ri! Antic!ineso oya%air Antic!ineo %ahesian Antic!ineo Tan$in-)anis Antic!ine

"hapter #

2:


27/59

5 Strati raphy and ;etro%eum Geo%o y

5 1 $ntroduction

5 2 $ntroduction to the ;etro%eum Geo%o y of rean %eya! area, the Sa!t (an"e 6ormation is over!ain by the .ambrian to Eocene p!atform

se#uence& t is "enera!!y simi!ar to the rest of 0eninsu!ar ndia& n S(06), the Ear!y to %idd!e

.ambrian eh!um 'roup !ies on the Eocambrian Sa!t (an"e 6ormation +'ee, 1B>B &

The eh!um 'roup inc!udes .ambrian 5he$ra and 5ussa 6ormations& These $ere deposited in

!ittora! to sha!!o$ marine environments& The basin $as up!ifted durin" ;rdovician to

.arboniferousJ therefore no sediments $ere deposited in S(06) +Shami, et a!&, 1BB> &

The eh!um 'roup is disconformab!y over!ain by the 0ermian 7i!a$ahan 'roup& t inc!udes the

Tobra, Dandot, archa and Sardahi 6ormations& The ate 0ermian 3a!uch 'roup $as eroded or

not deposited in the area& The ate 0ermian to .retaceous roc s from $est to east in the basin is

eroded due to si"nificant pre-0a!eocene tectonic up!ift in S(06)&

The predominant oi! producin" 0ot$ar basin !ies at the northern e/tremity of the upper ndus

basin of 0a istan& 0ot$ar )asin is bounded to the $est by ndus river and to the east by he!um

river in the zone of intensive!y deformed and imbricate thrust sheet ca!!ed the 7orth 0ot$ar Deformed 3one& This zone !ies to the north of Soan sync!ine& t comprises of northern fo!d zone

and the p!atform zone formed as a resu!t of Cima!ayan co!!ision bet$een ndian and Eurasian

p!ates $hich is sti!! active since 99 %a resu!tin" in continuous up!iftin", erosion and deposition&

Tectonica!!y 0ot$ar basin is bounded to the north by %ain )oundary Thrust +%)T and Sa!t

(an"e Thrust to the south& This zone consists of a number of antic!ines& Eocene and 0a!aeocene

carbonate succession are the proven reservoirs a!on" $ith .ambrian, 0ermian and urassic

c!astic sediments in different fie!ds +'hazi, et a!&, 2=18 &

&

2?


28/59

&

6i"ure -B Strati"raphic .o!umn of 0ot$ar (e"ion +Casany, et a!&, 2=12

The ear!y 0a!eocene marine trans"ression resu!ted thic deposition of the 0a!eocene to Eocene

carbonate-sha!e se#uence& t inc!udes the oc hart, 0ata!a, Sa esar and .hor"a!i 6ormations&

The carbonates of these formations form the principa! reservoirs for the accumu!ation of oi! in

the area& Can"u 6ormation is not identified in this part of S(06), $hich is eroded after

deposition and is identifiab!e on outcrop representin" residua! environments of deposition& The

Cima!ayan oro"eny initiated the Eocene-;!i"ocene up!ift and erosion in the S(06) +Shami, et

a!&, 1BB> &

The upper part of the strati"raphic section comprises of the %iocene to 0!eistocene non-marine

mo!asse deposits&These inc!ude roc s of the (a$a!pindi 'roup +%urree, 5am!ia! & ;n top of

these are Si$a!i s that inc!ude .hin4i, 7a"ri, Dho 0athan and Soan formations& The

trans"ressive mo!asse sediments represent the erosiona! products of the south$ard advancin"

2>


29/59

Cima!ayan thrust sheets& The mo!asses sediments in the southern S(06) !ie on the !o$er Eocene

carbonates&

The thic mo!asse sediments $ere rapid!y deposited in the Cima!ayan S(06) &The mo!asses

sediments are "enera!!y over pressured throu"hout the basin& The si"nificant part of thesesediments in depth fa!! in the zone of oi! $indo$, servin" as a re"iona! over pressured cap +sea!

roc over the reservoir roc s in northern S(06) +Shami, et a!&, 1BB> &

5 5 ;etro%eum Geo%o y

The 5ohat-0ot$ar depression has severa! features that ma e it a favorab!e site for hydrocarbon

accumu!ations& ocated on a continenta! mar"in, the depression is fi!!ed $ith thic deposits of

sedimentary roc s, inc!udin" potentia! source reservoir and cap roc & t contains a thic

overburden +about === m of f!uvia! sediments, $hich provide the buria! depth and optimum

"eotherma! "radient for seeps found in this area +Casany, et a!&, 2=12 &

5 5 1 Structure%eya!-5harpa surface structure is an east-$est trendin" narro$, steep, fau!ted antic!ine $ith t$o

ma4or thrusts cuttin" the structure !on"itudina!!y& The subsurface structure does not !ie direct!y

underneath the surface structure& There is a south$est shift of subsurface structure to the surface

structure& This shift is !i e!y due to re!ative!y youn"er transpressiona! movement of the b!oc s&

0revious e/p!oratory attempts $ere main!y based on the surface "eo!o"ica! mappin"& Seismic

data ac#uisition durin" 1B:9-1B:: had he!ped identify the subsurface structure confi"uration&

At the Eocene !eve! the sub-surface structure is defined as east-$est trendin" pop-up, sa!t cored,

doub!y p!un"in", "ent!e dippin" antic!ina! fo!d bounded by thrust fau!ts in the north and south &

The eastern part of the fo!d is s!i"ht!y ti"hter than the $est& %ost of the $e!!s $ere dri!!ed in the

centra! part of the Eocene structure& Trappin" mechanism in the %eya! 6ie!d is structura!&

+Casany, et a!&, 2=12 -

5 4 >ydrocar&on ;otentia%

The S(06) be!on"s to the cate"ory of e/tra continenta! do$n $arp basins, this account for 8>F

of the $or!d no$n petro!eum& t has severa! features suitab!e for hydrocarbon accumu!ation

inc!udin" continenta! mar"in, thic marine sedimentary se#uence, potentia! source and reservoir

2B


30/59

and cap roc s& The thic overburden of =8? m of mo!asse provides buria! depth and optimum

"eotherma! "radient for oi! formation&& The presence of an optima! combination of source,

reservoir and trap $ithin the oi! $indo$ resu!ted oi! and "as accumu!ation in oya%air, Toot,

%eya! and Dhu!ian oi!fie!ds +Shami, et a!&, 1BB> &

5 4 1 (eser#oir (oc The .ambrian, 0ermian, urassic, 0a!eocene and Eocene reservoirs are producin" oi! in S(06)&

The fractured carbonates of the Sa esar and .hor"a!i 6ormations are the ma4or oi! producin"

reservoirs in oya%air area& n %eya!, .hor"a!i and Datta 6ormations is ma4or oi! producin"

reservoirs& The Sa esar !imestone is !i"ht ye!!o$ "ray, massive and part!y do!omitized and

!oca!!y contains chert concretions& The .hor"a!i 6ormation is creamy ye!!o$ to ye!!o$ "ray,

si!ty, part!y do!omitic and thin bedded !imestone& The Datta 6ormation is dominant!y sandstone&

6i"ure -1= Sho$s the oi! and "as fie!ds of 0ot$ar 0!ateau +Shah, 1B?? &

.ore ana!ysis from %eya!, Dhu!ian and )a! assar oi!fie!ds sho$s that the primary porosity is

!ess than 1F in the .hor"a!i and Sa esar!imestones& The fracture porosity is re!ative!y hi"her in

$e!!s of north$estern 0ot$ar because the roc s deformed severa! times durin" the Cima!ayan

oro"eny& The fracture sets trend east$est, northeast-south$est and north$est-southeast& The

=


31/59

fractures deve!op para!!e!, ob!i#ue and perpendicu!ar to the fo!d a/es of antic!ines +Shami, et a!&,

1BB> &

5 4 2 Source (oc

The "ray sha!es of the %ian$a!i, Datta and 0ata!a 6ormations are potentia! source roc s inS(06& The oi! sha!es of the Eocambrian Sa!t (an"e 6ormation inc!ude 2?F to :F tota! or"anic

content +T;. in iso!ated poc ets of sha!es, and are considered as the source roc in S(06)

+Shami, et a!&, 1BB> &

5 4 5 'ap (oc sThe 5u!dana formation acts as cap for the reservoirs of .hor"a!i and Sa esar !imestones in

S(06)& The c!ays and sha!es of the %urree 6ormation a!so provide efficient vertica! and !atera!

sea! to Eocene reservoirs in S(06) $here ever it is in contact& The fo!!o$in" ;i! O 'as fie!d is

present in Upper ndus )asin that accounts for !ar"e supp!y of ener"y in 0a istan&

1

e *ormations /itho%o y i%?Gas*ie%d

;roduction

EoceneM0a!eoce

ne

oc hartM

Sa esarM

.hor"a!i

imestoneO

Sha!e

Dhurna!,

)a! assarO

%eya!

;i!

urassic Data O

Samana Su

Sandstone O

imestone

Dhu!ian, Toot

O

%eya!

;i!

0ermian

Tobra7i!a$a

hanO

3au!ch 'roup

.on"!omerat

eO

imestone

AdhiO

Dhurna! ;i!

.ambrian 5he$ra-

Sandstone Sandstone

AdhiO

%issa5es$a!

'as


32/59

"hapter $

4 Seismic $nterpretation

4 1 $ntroduction

n seismic, interpretation is defined as, the trans!ation of seismic information into "eo!o"ic terms&

Accordin" to +(obinson, et a!&, 1B>> interpretation is defined as, the transformation of the

seismic ref!ection data into a structura! picture by the app!ication of correction, mi"ration and

time depth conversion&

nterpretation is the transformation of seismic data into structura! and strati"raphic picture

throu"h a series of different steps& Thus threadin" to"ether a!! the avai!ab!e "eo!o"ica! and"eophysica! information inc!udin" the seismic and then inte"ratin" them a!! in a sin"!e picture

can on!y "ive a picture c!oser to the rea!ity&

The main purpose of seismic ref!ection survey is to revea! as c!ear!y as possib!e, the structures

and strati"raphy of the subsurface& The "eo!o"ica! meanin"s of seismic ref!ection are simp!y

indications of different boundaries $here there is a chan"e in acoustic impedance& These

observed contrasts are associated $ith different "eo!o"ica! structures are strati"raphic contacts&

To distin"uish different formations by means of seismic ref!ection is an important #uestion in

interpretin" seismic ref!ection data& 6or this purpose $e corre!ate the data $ith the $e!! data and

"eo!o"y of the area under observation& The $e!! data provides !in s bet$een !itho!o"y and

seismic ref!ections& The ref!ector identification is the ne/t sta"e by $hich the actua!

interpretation starts and it estab!ishes a strati"raphic frame b!oc for the main interpretation&

E/tractin" "eo!o"ica! structures from seismic data such as fo!din" and fau!tin" are referred to as

structura! interpretation +Te!ford, 2==8 &;n the other hand, e/tractin" non-structura! information

from seismic data is ca!!ed, PSeismic 6acies Ana!ysis &

4 2 Seismic Data $nterpretation )echni ues

There are t$o main techni#ues of seismic data interpretation i&e&

Strati"raphic Ana!ysisStructura! Ana!ysis

2


33/59

4 2 1 Strati raphic na%ysisStrati"raphic ana!ysis invo!ves the subdivision of seismic sections into se#uences of ref!ections

that are interpreted as the seismic e/pression of "enetica!!y re!ated sedimentary

se#uences&Strati"raphic ana!ysis invo!ves the de!ineatin" the seismic se#uences, $hich present

the different depositiona! units, reco"nizin" the seismic facies characteristic $ith su""est

depositiona! environment and ana!ysis the ref!ection characteristic variation to !ocate the both

strati"raphicchan"e and hydrocarbon depositiona! environment& D $or is especia!!y important

in reco"nizin" the strati"raphic feature $ith distinct shape&

Cydrocarbon accumu!ation is indicated by the amp!itude, ve!ocity, fre#uency or the chan"e in

$ave shape& ariation of the amp!itude $ith the offset is a!so an important hydrocarbon

indicator& Unconformities are mar ed by draina"e pattern that he!p to deve!op the depositiona!

environment& (eef, !enses, unconformity are e/amp!e of strati"raphic traps& +Sheriff, 1BBBSome of the parameters used in seismic strati"raphic interpretation are,

(ef!ection .onfi"uration(ef!ection .ontinuity(ef!ection Amp!itude(ef!ection 6re#uency

nterva! e!ocityE/terna! 6orm

4 2 2 Structura% na%ysisStructura! interpretation of 2-D Seismic ref!ection data inc!udes mar in" of the Corizons and the

fau!ts& ith the he!p of these mar ed structures $e try to interpret structura! traps, $hich is the

conse#uence of the structura! dynamics that have !ar"e e/tension in the "eo!o"ica! history& So $e

can say that structura! interpretation $ou!d a!so inc!ude the study of "eo!o"ica! history of the

area& n structura! interpretation main emphasis is on the structura! traps in $hich tectonics p!ay

an important ro!e& Tectonic settin" usua!!y "overns $hich types of structures are present and ho$

the structura! features are corre!ated $ith each other


34/59

vice versa& Even a mi"rated section not fu!!y fit for comp!e/ area !i e the area of study

+(obinson, et a!&, 1B>> &Some seismic section contains ima"es that can be interpreted $ithout

any difficu!ty& Discontinuous ref!ectors c!ear!y indicate fau!ts and undu!atin" ref!ections revea!s

fo!ded beds& %ost interpretation of structura! features are direct!y mar ed on seismic time

sections +(obinson, et a!&, 1B>>

Structura! interpretation usua!!y inc!udes,

dentification of Corizonsdentification of 6au!ts and 6o!ds

Above mentioned features are easi!y mar ed if the ref!ections on seismic section are c!ear, and

they are seen continuin" throu"h a certain "eo"raphic e/tent&

4 2 2 1 $dentification of >ori!ons

7orma!!y the horizons are named on the basis of the chec shot survey andMor on the basis of

S0 data& The synthetic seismo"ram can a!so be used to name the horizons accurate!y, to some

e/tent& )ut the namin" of the horizons can a!so be done on the basis of $e!! summery sheet&

4 2 2 2 $dentification of *au%ts and *o%dsThe appearance of the fo!ds and the fau!ts on the seismic section can be considerab!y distortedJ

especia!!y on immi"rated section i&e& antic!ines appear too broad, but the antic!ine crest is in its

proper subsurface position and sync!ines are narro$ed, but sync!ine a/is is in its proper

subsurface position&6au!ts a!most a!$ays have inc!ined fau!ts p!anes $hich $i!! be proper!y represented on!y on the

seismic !ine, crossin" the fau!t trace at the ri"ht an"!e& The interpretation of the fau!ts $i!! not be

proper on!y on the section ob!i#ue to the fau!t trace& Stri e s!ip fau!tin" is a!so difficu!t to detect&

Stri e s!ip fau!tin" may be suspected $hen mappin" sho$s offsets of ma4or structura! features&

4 5 1-D *or7ard Seismic Mode%in

An artificia! seismic ref!ection record, prepared from ve!ocity !o" data and density !o" data by

convo!vin" the ref!ectivity function derived from di"itized acoustic and density !o"s $ith the

$ave!et derived from seismic data is ca!!ed as PSynthetic Seismo"ram & Synthetic

seismo"ram is an artificia! mode! of the Earth that is used to mar the different "eo!o"ica!

horizon on the seismic section& t is direct one-dimensiona! mode! of acoustic ener"y trave!in"

throu"h different !ayers of Earth& The synthetic seismo"ram can be of "reat va!ue to the

8


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interpreter and it is best presented by sp!icin" it to an interpreted seismic section throu"h the

$e!! !ocation& Synthetic seismo"ram of %eya!-=> $e!! $as "enerated usin" 'eo"raphi/ Seismic

soft$are& n this procedure the petrophysica! !o"sJ Sonic +DT and )u! Density +(C;) ,

$hich provide the ve!ocity and density information of subsurface !ayers respective!y, are

used& The DT is a de!ay time !o" and its inverse "ives the ve!ocity& These !o"s are ac#uired in the

boreho!e& e use this ve!ocity and density data to compute a series of ref!ection coefficients

ca!!ed ref!ectivity series& Then a source (ic er $ave!et $ith a dominant fre#uency of 9 Cz is

"enerated& The ref!ectivity series is convo!ved $ith the source $ave!et to "et a synthetic

seismo"ram& n this case $e have performed the convo!ution $ith on!y one ref!ectivity series

+1D , thus on!y one seismic trace is "enerated& 'raphica!!y $e p!ot mu!tip!e copies to

disp!ay it in the form of a stac section& The synthetic seismo"ram vertica! units are meters or

feet and it can be converted into time units by usin" its o$n ve!ocity information& Syntheticseismo"ram is matched $ith the seismic section at the $e!! point to corre!ate the succession of

ref!ectors& t may a!so be used to ca!ibrate our seismic ve!ocities&

Synthetic seismo"ramR (ef!ection coefficient Source ave!et

The parameters used for the "eneration of synthetic seismo"ram are "iven be!o$L

Type of $ave!etL (ic er6re#uencyL 9 CzSamp!in" (ateL 2 %i!!iseconds0haseL 3ero 0hases

7umber of tracesL 8=

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4 5 1 Synthetic Seimo ram of Meya%-0@

Strati"raphic formation tops of %eya!-=> $e!!&

66 7A'( ======&=m

66 .C 7 ===1B9&=m

66 5A% A ==1?B=&?m

66 %U((EE ==2==1&Bm

66 5;CAT == 9BB&?m

66 %A% 5CE == : 9&?m

66 .C;('A == :>1&8m

66 SA5ESA( == ?9?& m

%eya!-=> $e!! has ei"ht formations encountered durin" dri!!in"& These are a!so confirmed by one

dimensiona! for$ard seismic mode!& 6or corre!ation ca!iper and "amma ray !o"s are used& )!ac

$i""!es represent the strati"raphic ref!ectors& .hor"a!i and Sa essar formations have a!so stron"

ref!ection in this $e!!&

To ma e one dimensiona! seismic mode! of %eya!-=> $e!! first of a!! sonic !o" and density !o"

$ere used to find out acoustic impedance& 6rom acoustic impedance ref!ection coefficient series$as determined& This ref!ection coefficient series then convo!ved $ith theoretica!!y ca!cu!ated

$ave!et no$n as P(ic er ave!et & After convo!vin" ref!ection coefficient series $ith (ic er

$ave!et one dimensiona! for$ard seismic mode! of %eya!--=> $e!! $as obtained&

The ref!ectors on the time sections are mar ed on the basis of Synthetic Seismo"ram because by

the he!p of Synthetic Seismo"ram $e no$ the time of the ref!ector and then $e mar it on the

seismic section&

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6i"ure 9-11 Synthetic Seismo"ram of %eya!-=>

4 5 2 ne Dimensiona% *or7ard Mode% of .e%% Meya%-0@To ma e one dimensiona! seismic mode! of %eya!-=> $e!! first of a!! sonic !o" and density !o"

$ere used to find out acoustic impedance& 6rom acoustic impedance ref!ection coefficient series

$as determined& This ref!ection coefficient series then convo!ved $ith theoretica!!y ca!cu!ated

$ave!et no$n as P(ic er ave!et & After convo!vin" ref!ection coefficient series $ith (ic er $ave!et one dimensiona! for$ard seismic mode! of %eya!--=> $e!! $as obtained&

?


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6i"ure 9-12 ;ne- Dimensiona! 6or$ard %ode! of %eya! =>

>


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4 4 )ime section of /ine A8-MY/-02

&

6i"ure 8-1 Time Section of B?-%@ -=2

4 )ime Section of /ine A8-MY/-08

6i"ure 8-18 Time Section of ine B?-%@ -=?

B


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4 6 )ime section of /ine A8- MY/-0A

6i"ure 8-19 Time Section of ine B?-%@ -=B

4 8 )ime Section of A8-MY/-12

6i"ure 8-1: Time Section of B?-%@ -12

8=


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4 @ )ime Section of A8-MY/-15

6i"ure 8-1? Time Section of B?-%@ -1

4 A *au%t ;o%y on Generation

A fau!t po!y"on represents the !atera! e/tent of dip fau!ts or stri e fau!ts havin" same trend& 6au!t

po!y"ons sho$ the sub-surface discontinuities by disp!acin" the contours& To "enerate fau!t

po!y"ons it is necessary to identify the fau!ts and their !atera! e/tent by !oo in" at the avai!ab!e

seismic data& f one finds that the same fau!t is present on a!! the dip !ines, then a!! points on base

map can be manua!!y 4oined to ma e a po!y"on&

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4 A 1 *au%t ;o%y ons 'onstructed at )he /e#e% of 'hor a%i *ormation

6i"ure 8-1> 6au!t 0o!y"ons .onstructed at the eve! of .hor"a!i 6ormation

4 A 2 *au%t ;o%y ons 'onstructed at the /e#e% of Sa esar *ormation

6i"ure 8-1B 6au!t 0o!y"ons 'enerated at the eve! of Sa esar 6ormation

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4 10 'ontour Maps

The resu!ts of seismic interpretation are usua!!y disp!ayed in map form& %appin" is partof the

interpretation of the data& The seismic map is usua!!y the fina! product of seismic e/p!oration, the

one on $hich the entire operation depends for its usefu!ness& The contours are the !ines of e#ua!

time or depth $anderin" around the map as dictated by the data + .offeen, 1B>: &

n constructin" a subsurface map from seismic data, a reference datum must first be se!ected& The

datum may be sea !eve! or any other depth above or be!o$ sea !eve! &6re#uent!y, another datum

above sea !eve! is se!ected in order to ima"e a sha!!o$ mar er on the seismic cross-section,

$hich may have a "reat impact on the interpretation of the zone of interest +.offeen, 1B>: &

.ontourin" represents the three-dimensiona! earth on a t$o dimensiona! surface& The spacin" of

the contour !ines is a measure of the steepness of the s!opeJ the c!oser the spacin", the steeper the

s!ope& A subsurface structura! map sho$s re!ief on a subsurface horizon $ith contour !ines that

represent e#ua! depth be!o$ a reference datum or t$o-$ay time from the surface& These contour

maps revea! the s!ope of the formation, structura! re!ief of the formation, its dip, and any fau!tin"

and fo!din"&

The interpreted seismic data is contoured for producin" seismic maps $hich provide a three-

dimensiona! picture of the various !ayers $ithin an area $hich is circumscribed by intersectin"

shootin" !ines& The pic ed times for each ref!ector are e/ported a!on" $ith the navi"ation data in

the form of an K@3 fi!e to be used for contourin"& The 5in"dom soft$are is used to "enerate a!!contour maps&

4 10 1 )ime 'ontour Map of 'hor a%i *ormation.hor"a!i formation is one of the main reservoir formations in %eya! area& This formation has

both ;i! O 'as content and is main!y composed of !imestone $ith some sha!y content& .hor"a!i

time contours maps are p!otted on the seismic base map a!on" $ith $e!! !ocations and fau!t

po!y"ons& 6au!t po!y"ons ma e pop-up structures $hich are suitab!e for hydrocarbon

accumu!ation& .ontour interva! in time contour maps is set as 9= mi!!iseconds& As the red co!or sho$in" the up!ifted zone of %eya! area because the time is !ess there so it indicates the up!ifted

structure $hich is pop-up structure and that is suitab!e for the hydrocarbon accumu!ation and the

$e!! in our area are a!so dri!!ed in that zone& The pop-up structures are bounded by t$o ma4or

fau!ts&

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6i"ure 8-2= Time .ontour %ap of .hor"a!i 6ormation

4 10 2 )ime 'ontour Map of Sa esar *ormationSa esar formation is a!so one of the main reservoir formations second in %eya! area&& Sa asser

formation !ies be!o$ .hor"a!i formation in a!! seismic sections& 6au!t po!y"ons of Sa asser

formation are simi!ar to .hor"a!i formation $hich indicates the presence of same fau!ts on both

formations& .ontour interva! in time O depth contour maps is 9= mi!!iseconds&

Time variation is sho$n in contour map the b!ue co!ored portion sho$s deepest part of formation

red co!or from sho$s hi"hest point no$n as pop up structure and it is the most favorab!e area

for hydrocarbon e/traction from Sa asser formation&

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6i"ure 8-21 Time .ontour %ap of Sa esar 6ormation

4 10 5 )ime 'ontour Maps of ,amma% *ormation 7amma! formation has a!so reservoir properties& This formation is a!so main!y composed of

!imestone $ith sha!y content at its bottom !eve!& 6au!t po!y"on of 7amma! formation have same

trend as those of .hor"a!i formation and Sa esar formation& A pop up structure e/ists bet$een

the same fau!t po!y"ons& .ontour interva! in time O depth .ontour maps is 9= mi!!iseconds&

Time variation is sho$n by the co!or red co!or sho$s hi"hest point no$n as pop up structure

and it is favorab!e area for hydrocarbon e/traction from 7amma! formation&

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6i"ure 8-22 Time .ontour %ap of 7amma! 6ormation

4 11 Depth 'ontours

Depth contour maps are a!so formed as the time contours difference bet$een depth and time

contours is that in the time contours the formation is contoured $ith time and the depth contours

are formed accordin" to the depth of formations&

4 11 1 Depth 'ontour Map of 'hor a%i *ormationThe b!ue co!or in contour map sho$in" the sha!!o$ part $ith respect to surroundin"s $hich is

sho$in" the up!ifted potion of the pop-up structure $hich is suitab!e for the hydrocarbon

accumu!ation and $e!! in %eya! area are a!so insta!!ed in this portion&

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6i"ure 8-2 Depth .ontour %ap of .hor"a!i 6ormation

4 11 2 Depth 'ontour Map of Sa ear *ormationSa esar !imestone is a!so act as the reservoir in the %eya! area in depth contour map of sa esar

formation& The pin co!our zone sho$in" the sha!!o$ part $ith respect the surroundin"s $hich is

sho$in" the up!ifted part of the pop-up structure $hich is suitab!e for the hydrocarbon

accumu!ation and $e!! in %eya! area are a!so insta!!ed in this zone&

6i"ure 8-28 Depth .ontour %ap of Sa esar 6ormation

8?


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"hapter %

Seismic ttri&utes

1 Seismic ttri&utes

Seismic attributes are a set of properties computed from input seismic data $hich consist of

amp!itude as the basic attribute& Attributes can be ca!cu!ated on the pre-stac as $e!! as post-

stac data& The most common post stac attributes are instantaneous attributes that are computed

at each samp!e of seismic trace& The seismic ener"y is basica!!y a mechanica! ener"y $hich has

t$o components inetic and potentia! ener"y& Throu"h e/periments it has found that $e can on!y

measure the inetic ener"y& 7o$ to compute instantaneous attributes $e need to ca!cu!ate theima"inary potentia! ener"y component of seismic ener"y& The ima"inary component is basica!!y

a B= de"rees phase rotated version of the input seismic trace and therefore can be computedᵒ

throu"h the Ci!bert transform +Taner, et a!&, 1B:B &

2 pp%ications of Seismic ttri&utes

Uses of Seismic attributes inc!ude

To chec seismic data #ua!ity identifyin" artifacts0erformin" seismic facies mappin" to predict depositiona! environmentCydrocarbon p!ay eva!uation0rospect identification and ris ana!ysis(eservoir characterization

5 )ypes of ttri&utes

The defau!t attribute of Seismic data is Amp!itude&Attributes can be computed from pre-stac or

from post-stac data, before or after time mi"ration& The procedure is the same in a!!of these

cases& Attributes can be c!assified into many types but there are t$o broad c!assifications of the

attributes +Taner, et a!&, 1B:B & They inc!udeJ

5 1 Geometrica% attri&utes'eometrica! attributes are used to enhance the visibi!ity of the "eometrica! characteristics

of seismic dataJ they inc!ude dip, azimuth, and continuity&

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5 2 ;hysica% ttri&utes0hysica! attributes have to do $ith the physica! parameters of the subsurface and so re!ate

to !itho!o"y& These inc!ude amp!itude, phase, and fre#uency&

5 2 1 En#e%ope of )raceThe enve!ope is the enve!ope of the seismic si"na!& t has a !o$ fre#uency appearance and on!y

positive amp!itudes& t often hi"h!i"hts main seismic features& The enve!ope represents the

instantaneous ener"y of the si"na! and is proportiona! in its ma"nitude to the ref!ection

coefficient&The enve!ope is usefu! in hi"h!i"htin" discontinuities, chan"es in !itho!o"y, fau!ts and

chan"es in deposition, tunin" effect, and se#uence boundaries& t a!so is proportiona! to

ref!ectivity and therefore usefu! for ana!yzin" A ; anoma!ies& This attribute is "ood for !oo in"

at pac a"es of amp!itude& This attribute represent main!y the acoustic impedance contrast, hence

ref!ectivity& t a!$ays remains positive $hether the ref!ection coefficient is positive or ne"ative

and it hi"h!i"hts the petro!eum p!ay as a bri"ht spot& This attribute is main!y usefu! in

identifyin"L

)ri"ht spots&"as accumu!ation&Se#uence boundaries, ma4or chan"es or depositiona! environments&Unconformities&%a4or chan"es of !itho!o"y&

oca! chan"es indicatin" fau!tin"&

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6i"ure 9-29 Enve!ope of ine B?-%@ -=2

5 2 2 pparent ;o%arity Some of the instantaneous attributes such as instantaneous fre#uency sho$ a very sharp or

crispy si"nature therefore are difficu!t to interpret thus $ave!et attributes are computed our each

cyc!e of the seismic attribute +Taner, et a!&, 1B:B & ave!et attributes sho$ a b!oc y response as

they represent avera"e va!ue over each cyc!e in the seismic trace&

Avera"e ener"y is a post stac attribute that computes the sum of the s#uared amp!itudes divided

by the number of samp!es $ithin the specified $indo$ used& This provides a measure of

ref!ectivity and a!!o$s one to map direct hydrocarbon indicators $ithin a zone of

interest&Avera"e ener"y e/hibits more contrast than ref!ection stren"th and its "reater contrast are

on!y due to ho$ it presents the information&

9=


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6i"ure 9-2: Avera"e Ener"y of ine B?-%@ -=2

5 2 5 ;hase ttri&utesThe ar"ument of the comp!e/ function is defined as the phase& The phase component is

independent of seismic amp!itude therefore can be used as a "ood indicator of ref!ector

continuity&

6i"ure 9-2? 0hase Attributes of ine B?-%@ -=2

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5 2 4 $nstantaneous ;hase *re uencyThe computations of instantaneous fre#uency as the time derivative of phase, and its meanin"

has been the sub4ect of a number of papers& t has been sho$n that the instantaneous fre#uency

attribute re!ates to the centroid of the po$er spectrum of the seismic $ave!et& nstantaneous

fre#uency attribute responds to both $ave propa"ation effects and depositiona! characteristics,

hence it is a physica! attribute and can be used as an effective discriminator& ts uses inc!ude,

fracture zone indicator, fractures may appear as !o$er fre#uency zones, bed thic ness indicator&

Ci"her fre#uencies indicate sharp interfaces such as e/hibited by thin!y !aminated sha!es, !o$er

fre#uencies are indicative of more massive beddin" "eometries, e&"& sand-prone !itho!o"ies&

6i"ure 9-2> nstantaneous 0hase 6re#uency of ine B?-%@ -=2

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"hapter &

6 ;etrophysics

6 1 $ntroduction

0etrophysics is the study of the physica! and chemica! properties that describes the occurrence

and behavior of the roc s, soi!s and f!uids& To accurate!y characterize an oi! or "as reservoir,

measurements such as resistivity and density are made, from $hich effective porosity, saturations

and permeabi!ity can be #uantified&

6 2 )ypes of /o s'amma (aySpontaneous 0otentia!.a!iper o"(esistivity o"Sonic o"Density o"

7eutron o"

6 2 1 Gamma (ay /o'amma ray !o""in" is a method of measurin" natura!!y occurrin" "amma radiation to

characterize the roc or sediment in a boreho!e or dri!! ho!e& t is a $ire!ine !o""in" method used

in minin", minera! e/p!oration, $ater-$e!! dri!!in", for formation eva!uation in oi! and "as $e!!

dri!!in" and for other re!ated purposes& Different types of roc emit different amounts and

different spectra of natura! "amma radiation & n particu!ar, sha!es usua!!y emit more "amma rays

than other sedimentary roc s, such as sandstone , "ypsum , sa!t , coa! , do!omite , or !imestone

because radioactive potassium is a common component in their c!ay content, and because the

cation e/chan"e capacity of c!ay causes them to absorb uranium and thorium & This difference inradioactivity bet$een sha!es and sandstonesMcarbonate roc s a!!o$s the "amma too! to

distin"uish bet$een sha!es and non-sha!es&

9

https://en.wikipedia.org/wiki/Gamma_radiationhttps://en.wikipedia.org/wiki/Boreholehttps://en.wikipedia.org/wiki/Formation_evaluationhttps://en.wikipedia.org/wiki/Gamma_rayhttps://en.wikipedia.org/wiki/Shalehttps://en.wikipedia.org/wiki/Shalehttps://en.wikipedia.org/wiki/Sandstonehttps://en.wikipedia.org/wiki/Gypsumhttps://en.wikipedia.org/wiki/Gypsumhttps://en.wikipedia.org/wiki/Halitehttps://en.wikipedia.org/wiki/Coalhttps://en.wikipedia.org/wiki/Dolomitehttps://en.wikipedia.org/wiki/Dolomitehttps://en.wikipedia.org/wiki/Limestonehttps://en.wikipedia.org/wiki/Cation_exchange_capacityhttps://en.wikipedia.org/wiki/Uraniumhttps://en.wikipedia.org/wiki/Thoriumhttps://en.wikipedia.org/wiki/Gamma_radiationhttps://en.wikipedia.org/wiki/Boreholehttps://en.wikipedia.org/wiki/Formation_evaluationhttps://en.wikipedia.org/wiki/Gamma_rayhttps://en.wikipedia.org/wiki/Shalehttps://en.wikipedia.org/wiki/Sandstonehttps://en.wikipedia.org/wiki/Gypsumhttps://en.wikipedia.org/wiki/Halitehttps://en.wikipedia.org/wiki/Coalhttps://en.wikipedia.org/wiki/Dolomitehttps://en.wikipedia.org/wiki/Limestonehttps://en.wikipedia.org/wiki/Cation_exchange_capacityhttps://en.wikipedia.org/wiki/Uraniumhttps://en.wikipedia.org/wiki/Thorium


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6 2 2 Spontaneous ;otentia% /oThe Spontaneous 0otentia! +S0 !o" measures the natura! or spontaneous potentia! difference

bet$een the boreho!e and the surface, $ithout any app!ied current& t $as one of the first $ire!ine

!o"s to be deve!oped, found $hen a sin"!e potentia! e!ectrode $as !o$ered into a $e!! and a

potentia! $as measured re!ative to a fi/ed reference e!ectrode at the surface&

The most usefu! component of this potentia! difference is the e!ectrochemica! potentia! because it

can cause a si"nificant def!ection in the S0 response opposite permeab!e beds& The ma"nitude of

this def!ection depends main!y on the sa!inity contrast bet$een the dri!!in" mud and the

formation $ater, and the c!ay content of the permeab!e bed& Therefore, the S0 !o" is common!y

used to detect permeab!e beds and to estimate c!ay content and formation $ater sa!inity&

6 2 5 'a%iper /oA ca!iper !o" is a $e!! !o""in" too! that provides a continuous measurement of the size and shape

of a boreho!e a!on" its depth and is common!y used in hydrocarbon e/p!oration $hen dri!!in"

$e!!s& The measurements that are recorded can be an important indicator of cave ins or sha!e

s$e!!in" in the boreho!e, $hich can affect the resu!ts of other $e!! !o"s&

6 2 4 (esisti#ity /o(esistivity !o""in" measures the subsurface e!ectrica! resistivity, $hich is the abi!ity to impede

the f!o$ of e!ectric current& This he!ps to differentiate bet$een formations fi!!ed $ith sa!ty $aters+"ood conductors of e!ectricity and those fi!!ed $ith hydrocarbons +poor conductors of

e!ectricity & (esistivity and porosity measurements are used to ca!cu!ate $ater saturation&

(esistivity is e/pressed in ohms or ohms meter, and is fre#uent!y charted on a !o"arithm sca!e

versus depth because of the !ar"e ran"e of resistivity& The distance from the boreho!e penetrated

by the current varies $ith the too!, from a fe$ centimeters to one meter&

6 2 Sonic /oSonic !o""in" is a $e!! !o""in" too! that provides a formation


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6 2 6 Density /oDensity !o""in" is a $e!! !o""in" too! that can provide a continuous record of a formationHs bu!

density a!on" the !en"th of a boreho!e & n "eo!o"y, bu! density is a function of the density of the

minera!s formin" a roc +i&e&matri/ and the f!uid enc!osed in the pore spaces& This is one of

three $e!! !o""in" too!s that are common!y used to ca!cu!ate porosity, the other t$o bein" sonic

!o""in" and neutron porosity !o""in" &

6 2 8 ,eutron /oThe neutron porosity !o" $or s by bombardin" a formation $ith hi"h ener"y epitherma!

neutrons that !ose ener"y throu"h e!astic scatterin" to near therma! !eve!s before bein" absorbed

by the nuc!ei of the formation atoms& Dependin" on the particu!ar type of neutron !o""in" too!,

either the "amma ray of capture, scattered therma! neutrons or scattered, hi"her ener"y

epitherma! neutrons are detected& The neutron porosity !o" is predominant!y sensitive to the

#uantity of hydro"en atoms in a particu!ar formation, $hich "enera!!y corresponds to roc

porosity&

6 5 ;etrophysica% ;roperties of Meya% .e%%-15

)y usin" the $e!! data "iven by the the D'0. $e had ca!cu!ated the petrophysica! properties of

meya! e!!-1 usin" the AS fi!e of the $e!! in $hich $e had a!! the data of the !o" run in the

$e!!& e have ca!cu!ated different petrophysica! properties of the $e!!-1 and sho$n the "raph&

The upper part e/tends from 1 9?> feet depth to 1 ? 9 feet and consists of a!ternatin" beds of

sha!e and sandstone& A > feet thic bed of sha!e is present at the depth of 1 :?9 feet $hich is

indicated by hi"h neutron porosity, density porosity and "amma-ray curves& This part can be

considered as a sea! roc for under!yin" oi! reservoir &The !o$er part !ies at the depth of 1 ? :

feet and e/tends to 1 >9= feet depth, conta

Documents

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