geological overview of trinidad and tobago

8/13/2019 Geological Overview of Trinidad and Tobago

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ACKNOWLEDGEMENTS

The authors wish to thank the Geological Society of Trinidad and Tobago, UTTCampus, Esperanza Rd, rechin Castle, Cou!a, for allowing the release of rele!ant

information on the "ourth Caribbean Geological Conference, Trinidad #$%&, and the

"ourth 'atin (merican Geological Congress Trinidad and Tobago, #$)$* +e would also

like to thank enesh Ramnarace, Reser!oir Engineer of -rimera Group of Companies,./0 "orest Reser!e Road "yzabad, Trinidad +est 1ndies, for sourcing information which

made possible the publication of this document*


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GEOGRAPHICAL LOCATION

Trinidad and Tobago comprises the southernmost of the Caribbean islands and issituated north of and opposite the mouth of the 2rinoco Ri!er* 1t is separated from the

South3(merican coast by the Gulf of -aria* Tobago is located /4km 540 miles6 northeast

of Trinidad and has an area of /00 s7*km 5#40 s7*miles6, while Trinidad has an area of

8949 s7*km* The island of Tobago is predominantly !olcanic in origin: hence the reasonfor the absence of onshore hydrocarbons* There has howe!er, been recent findings of

large gas fields off the southwest coast of Tobago*

Trinidad is situated at a triple ;unction formed by the collision of the South3(merican, Caribbean and


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The stratigraphy of Trinidad can be assessed in terms of three broad tectostratigraphic

phasesA -assi!e >argin

"oredeep

"oreland

-otential oil3prone source rocks are recognized in the middle to 'ate Cretaceous -assi!e

>argin and -aleogene foredeep sedimentary se7uences* The South3East Caribbean

represents a comple= plate interaction zone* The "oreland Thrust elt occupies large

areas of argin of northern South (merica de!eloped

during the Early to 'ate Cretaceous period* 1t is represented by the Cuche, Gautier,


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MA5OR OILFIELDS OF ONLAND

TRINIDAD


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Oi#ie$ Na&e S!ruc!ura Regi&e

o# Ma.or

Pro$uc!i*e 6o"e)

Age o# Ma.or

Pro$uc!i*e 6o"e

Na&e o# Ma.or

Pro$uc!i*e 6o"e

7ear Di)co*ere$ Appro8i&a!e

9!i&a!e Sie

+acre)-

alata3o!allius etached o!erthrust 'ower >iocene Berrera Sands #$&4 Small

arrackpore3-enal etached o!erthrust 'ower >iocene Berrera Sands #$##@#$8# 'arge

righton3-oint

'igoure

etached

o!erthrust@StrikeSlip3En echelon

-liocene

'ower >iocene

>orne lEnfer

io3-liocene Catshill #$&4 >edium

Coora3Duarry3

>orne iablo

Strike Slip

Stratigraphic

>io3-liocene Cruse3"orest3>orne

lEnfer

#$/% %&00

"yzabad3"orestReser!e

Strike Slip Enechelon (nticline

>io3-liocene Cruse3"orest #$#8@#$40 /$00

GuayaguayareGroup etached growthfault related >io3-liocene >oruga #$##@#$4)@#$&$ >edium

>oruga East Strike Slip

(nticline

-liocene "orest E7ui!alent #$&4 Small


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2ropouche etached o!erthrust 'ower >iocene Retrench Sands #$4# Small

-alo Seco 3 Erin3Grande Ra!ine

Strike Slip Stratigraphic

>io3 -liocene Cruse "orest >orne lEnfer

#$#4@#$ #0 000

-oint "ortin

-arrylands Guapo

Strike Slip

(nticlines

>io3-liocene Cruse "orest

>orne lEnfer

#$09@#$#4 4%)0

Rock ome East5>oruga iocene Berrera Sands #$&) Small


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The main oil producing sands are the Cruse and "orest sands*

PALO SECO FIELD

1t is situated near the South3Central coast of Trinidad*

1t has a surface area of appro=imately #0,000 acres*

'ies near the crest of the >orne iablo uplift*

Structurally located on the southern limb of the Siparia@Erin basin and is

intersected by two 546 ma;or faultsA

1* The 'os a;os fault11* The Santa "lora fault

The main oil3bearing reser!oir is the Top Cruse 5>iocene6 sandstone*

(-1 gra!ity of crude range from #8H 3 /%H (-1*

%RIGHTON ; POINT LIGO9RE FIELD

This is a gentle dome on the crest of which the -itch 'ake is situated*

( clayey "orest3Cruse comple= follows the top 'a rea and >oruga beds*


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The Cruse sandstone reser!oir bed has passed into clay, and production comes

form younger >iocene sands*

>ost of the oil in this field has come from sandy, deltaic >iocene lens3typereser!oirs*

Ultimate reco!erable Reser!es #4)$ >>2*

The -enal@arrackpore anticline formed as a result of middle >iocene

compression that occurred as a result of obli7ue collision of the Caribbean and

South (merican plates* ( transpressional episode occurred during the late

-liocene causing re;u!enation of faults and additional folding*

'ocal Structure South3west plunging -enal@arrackpore anticline with aregional tilt of appro=imately ##H toward the southwest*

Thrust faulted anticlinal traps with multiple pays: numerous stratigraphic traps*


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G9A7AG9A7ARE FIELD

2riginally disco!ered in #$04*

'ighter paraffinic oil is produced*

-roduction occurs principally from the >iocene Gros >orne sands*

OROPO9CHE FIELD

'ight oil and gas ha!e been found in the Ste* Croi= formation, but only in small7uantities*

MOR9GA WEST FIELD

(nticline traps are predominant in this area*

The oldest horizon is the Gautier formation*

The Jaramat and Berrera sands are the main producing reser!oirs in this area*

(-1 Gra!ity of crude in these reser!oirs ranges from 4%3//H*

900 acres of this field has been de!eloped*

The number of wells drilled in this field was recorded as 4&) in the year 400#*

Cumulati!e production in this area is greater than #0 million barrels*


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Figure ,: Mai" Oi#ie$) o# O"a"$ Tri"i$a$


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DISC9SSION

The east3west trend of the


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geological overview of trinidad and tobago

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