Tectonic evolution of structures in Southern Sindh Monocline,Indus Basin,Pakistan formed in multi-extensional tectonic episodes of Indian Plate

There are a number of structures and structural styles found in extensional tectonic settings of the world,and it is a big challenge to study the evolution of these structures. Evolution of structures formed in extensional tectonic settings have been studied by researchers on different extensional basins of the world. Southern Sindh Monocline lies on the western corner of Indian Plate and the tectonic history of Indian plate has also experienced different extensional episodes, and its journey rifted from Gondwanaland to its final welding to Asia. The aim of this study is to figure out the evolution of structures in the subsurface of Southern Sindh Monocline, Pakistan using the seismic data interpretation and flattening of horizons approach. Structures within the subsurface of Southern Sindh Monocline have been characterized by different tectonic episodes of Indian plate while rifting from Gondwanaland, rifting from other plates at different geological times and to its collision with the Asia. Basic structures within study area are classified into nine types while the structural styles have been classified into six types as horst and grabens, dominos, crotch, synthetic and antithetic, negative and flashlight structural style. The structures within the study area revealed evidence for three major structural episodes which can be characterized as Episode 1: Structures associated with rifting of Indian plate from Gondwanaland during Late Jurassic to Early Cretaceous, Episode 2: Modification and reactivation of previous structures while Madagascar rifted from Indian Plate during the Middle Cretaceous and during Episode 3: Inversion and reactivation of structures occurred when Indian Plate collided with Asia during Early Eocene.

Morphological features of continental shelf margin:Examples from the Pakistan Offshore

This paper describes various morphological features of continental shelf and their present-day analogues both present in surface and subsurface data. Most of the examples are taken from Pakistan Offshore.Identification of subsurface features from wireline logs and seismic data is very significant for the application of facies identification in the field of petroleum geosciences, sequence stratigraphy and sedimentology, which is based on the analysis of various lithological characteristic of facies, as well as their geometrical distributions in the basin.

Sedimentary facies interpretation of Gamma Ray(GR)log as basic well logs in Central and Lower Indus Basin of Pakistan

Rocks and most type of soils emit Gamma Ray （GR） in varying amount. The emitting ele- ments of primary gamma radiations include potassium 40, uranium, and thorium which are associated with rocks forming minerals in variable amount. GR log is used to predict the varying lithology in borehole by measuring the spontaneous emission of GR radiation from rocks. Role of GR logs in the identification of subsurface facies is the main focused research theme of this manuscript including with objective of brief introduction of GR log and its applications in the identification of facies in the field of Petroleum Geosciences by analyzing the examples of GR log（s）from wells. Lower Indus Basin. Pakistan.

Possible origin of inert gases in hydrocarbon reservoir pools of the Zindapir Anticlinorium and its surroundings in the Middle Indus Basin, Pakistan

The natural gas in several gas fields in Pakistan is associated with varying percentages of inert gases（e.g.,CO;, N;, and H;S）. The heating capacity of such natural gas is measured in British thermal units（BTU） in Pakistan and is based on the combustion of the natural gases. The study area of this work belongs to the Middle Indus Basin, which also covers some parts of the Sulaiman Foldbelt and the Punjab Platform.Petroleum wells drilled in the study area contain inert gases（mostly CO;and N;） in varying percentages,which decreases the BTU value of sweet gases and the economic value of the gas reserves.Attempts were made to analyze the varying compositions of inert gases（mostly CO;and N;） along the deep-seated basement faults in the Zindapir Anticlinorium, eastern Sulaiman Foldbelt, but no specific relation could be established. Similarly, geothermal gradient zones were identified and the distribution of inert gases in these zones was studied, but even so, no well-established relation could be tracked.However, variations in the amounts of inert gases in the Chiltan Limestone of the Rodho Structure and the Afiband Structure point to the generation of in situ inert gases because both wells were drilled on the same anticlinorium and share the same geology, and possibly, the same source rock. Post-accumulation changes probably play an important role in the generation of in situ inert gases in varying concentrations.H;S is also present in some parts of the Indus Basin. Therefore, a brief discussion about the possible origin of the H;S is also included in this paper.