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Geology/petroleum geology ( traps , downstream and upstream activities of petroleum)


QUESTION: AOA sir , i have two questions to ask you. At first ,i wanted to ask you about the the traps i.e what are compressional , extensional , transtensional and transpressional traps and where they are located in Pakistan ? My second question is that what are the upstream and downstream activities of petroleum ?

ANSWER: Maham,

Good question.

The Indian Plate's collision with the Eurasian Plate was initially in a NWN direction and then it gradually became northerly and now it is more of a NEN direction. So all kinds of compressional, extensional and the mix like transpresion regime (compression and strike slip) or transtension regime (a mix of tension and strike-slip)have been acting on the rocks, which resulted in the ranges, plateau, escarpment etc, and in the subsurface horst-graben structural geometry in Badin area. However, the earth is so dynamic that there is always a mix of different kinds of tectonic forces. We classify them as per the force which is dominant.

In a compressional regime the forces act head-on like if you press a card board with your hands, it gets folded with the axis at right angle to the direction of force you are applying by your hands. This regime results in thrusts and fault bounded folds (traps), as we see in Potwar. The Arabian Plate and the Eurasian Plate are colliding head-on along offshore Makran resulting in the accretion of strata; though there seems to be an oblique factor too as the strike of the accretionary wedges is not exactly parallel to the subduction zone located in the offshore.

Extensional regime is opposite to that, like you pull apart a card board and it breaks if the exerted force is more than its strength. This regime results in a series of normal faults, and the faulted blocks move up and down (Isostacy) to cause the horst-graben geometry as we see in Badin area. It is the main trapping mechanism in Badin area.

The transpression regimes are formed during oblique collision of tectonic plates. Typically a mixture of oblique-slip thrust faults and strike-slip or transform faults are formed. Microstructural evidence of transpressional regimes can be rodding lineations, mylonites, augen-structured gneisses, mica fish and so on. I would say that Sulaiman Range is an example, though compression was a dominant force with significant oblique factor at some places.

On the other hand Kirthar Range is a result of compression with a minor oblique factor. However, in the northern part where the Sibi Re-entrant has imparted oblique forces on both the northern Kirthar Range and the western part of the Sulaiman Range (lobe), the oblique factor is significant. Here, normal domal structures (traps) are formed as we see in both Sulaiman and the Kirthar Ranges.  

Transtension regimes are oblique tensional environments. Oblique, normal geologic fault and detachment faults in rift zones are the typical structural manifestations of transtension conditions. Microstructural evidence of transtension includes rodding or stretching lineations, stretched porphyroblasts, mylonites, etc. Badin area is more in a transtensional regime (not just tensional as mentioned above).

Hope the above is of help.

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QUESTION: sir thanks alot for your feedback but sorry , i couldn't find in your answer , where exactly extensional , transpressional and transtentional traps in Pakistan has formed and why ?
i know the phenomenon of the formation of those traps but how did they form in Pakistan and where , that's what i want to know .
i hope you will let me know about it .


Please read my previous response again. I have mentioned about the regions in Pakistan with reference to the tectonic regime.

I inadvertently left out the last part. The upstream deals with finding the oil and gas, while downstream are those who market the oil and gas. PPL, OGDCL, OMV, ENI, POL etc are upstream companies, while SSGC, SNGPL, refineries etc belong to downstream sector.


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Nusrat Kamal Siddiqui (Mr)


I am a petroleum exploration geologist with about 40+ years of diversified experience. I can answer questions on stratigraphy, log interpretation, field studies based on set of logs and core results, general geology etc. Can provide guidance for career planning in earth sciences. Can not help in questions about hard rocks, igneous petrology & mineralogy, sequence stratigraphy and seismic.


Petroleum Exploration - field geology, stratigraphy, prospect generation, interpretation of satellite imagery (visual), log interpretation.

Retired in May, 2006 as Senior Manager Exploration from Pakistan Petroleum Limited after serving 26 years. Since then continuing in active service with petroleum exploration companies.A cumulative experience of about 40 years covers 30 years in petroleum exploration, 5 years hydrogeology experience in Libya, and about 5 years of dam geology in Pakistan.

-AAPG Bulletin (Vol.88, July, 2004); paper on Sui Main Limestone (Eocene), a prolific gas reservoir in Pakistan. -Have presented papers on diversified topics ranging from spirituality, flood control, remote sensing and off course geology in France, Nepal, Bangladesh, Sri Lanka, UAE, Kashmir, India and Pakistan that have been published in respective Special Proceedings. -ONGC Bulletin(India) Vol. 44, Number 2, December, 2009; Chapter 19.A & 19.B on basin architecture and stratigraphy of Pakistan, p.402-474.

BSc Honours in Geology and Master of Science in Petroleum and Structural Geology. PGD from ITC, The Netherlands.

Awards and Honors
-Remained Active Member of AAPG from 1990-2006; founding member of PAPG (a local affiliate of AAPG). -Life member of SEGMITE & AGID, and Senior Editor of SEGMITE magazine. -Member of the Board of Studies, i. Department of Petroleum & Gas Engineering (BUITMS, Quetta), and ii. Geology Department, Sindh University, Jamshoro. -Member of Stratigraphic Committee of Pakistan. -Represented Mining Journal, UK in Pakistan till 2007. -Chairman of Annual Technical Conference (ATC)& Oil Show, an SPE/PAPG annual event, in 2003. -Chairman Technical Committee (ATC, 2002).

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