A DETAILED FRACTURE ANALYSIS OF TRIASSIC KINGRIALI FORMATION IN THE WESTERN SALT RANGE AND TRANS INDUS RANGES (SURGHAR RANGE), PAKISTAN

Abstract

The current research studies carried out on Kingriali Formation western Salt Range (Nammal Gorge and Zaluch Nala) and Trans Indus Ranges (Surghar Range) to understand the structure architecture of the area. The stratigraphic sequence exposed in study area ranging in age from the Permian to Miocene/Pliocene, resulting from the collision of the Indian plate with the Eurasian plate, north-south compressional stresses caused considerable deformation. Fracture analysis of Triassic Kingriali Formation is carried out in research area i.e., Nammal Gorge, Zaluch Nala, and Surghar Range section. Using Circular Inventory Method, the petrophysical properties e.g., fracture density, fracture porosity and fracture permeability are calculated. These calculated data are plotted crossly on graphs to determine the relationship between them. The relationship between fracture density and fracture porosity/fracture porosity and fracture permeability is uniform, whereas the relationship between fracture density and fracture permeability is not. The reservoir potential for each formation was evaluated qualitatively using the Naturally Fracture Reservoir (NFR) classification. Which represent that Kingriali formation is type-3 to type-1 type reservoir in study area. The fracture system varies in different sections therefore Nammal Gorge and Surghar Range Section have high reservoir potential while Zaluch Nala Section have comparatively low reservoir potential. The maximum stress direction (δ1) of 23 stations lies in NW direction 6 stations in NE direction while 1 station lies in SE direction. This indicates that the deformation i.e., fold, fault, joint and fracture in study area is due to the North-South compressional stresses.