TITLE:
Structural Styles and Petroleum Potential of Miano Block, Central Indus Basin, Pakistan
AUTHORS:
Saif-Ur-Rehman K. Jadoon, Muhammad F. Mehmood, Zohaib Shafiq, Ishtiaq A. K. Jadoon
KEYWORDS:
Extensional Regime, Horst and Graben
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.10,
October
19,
2016
ABSTRACT: The
main purpose of this research article is to evaluate the structural styles and
hydrocarbon potential of Miano Block using seismic and well log data. The Miano
Block discovered in 1993 is located in the Central Indus Basin which is a part
of an extensional regime exhibiting normal faulting, formed as a result of
split of the Indian Plate firstly from Africa and then from Madagascar and
Seychelles. Tectonically, the Miano Block lies on the Panno-Aqil graben between
two extensive regional highs i.e. Jacobabad-Khairpur
High and Mari Kandhkot High. Four migrated seismic lines were used for structural
enhancement; P2092-111, P2092-113 and P2092-115 (dip lines) and P2092-110
(strike line). Time and depth contours were generated for four horizons,
HabibRahi Formation, Sui Main Limestone, Ranikot Formation and Lower Goru Formation
which showed the presence of horst and graben structures in the subsurface. The
interpretation of horst and graben structures is based on a parallel set of
NS-oriented high-angle planar normal faults with dips either towards SE or SW
with majority of the faults dipping towards the SW. The faults are observed to
exhibit slight disruption of strata with limited displacement to the order of
about 50 m in Lower Goru Formation. Thus, horst and graben structures with NS
trend in the study area are interpreted. The NS trend of these structures along
with similar structural dip is inconsistent to the NW-SE orientation of
regional structures i.e. Panno- Aqil graben and the
Jacobabad-Kharipur and Mari-Kandhkot Highs indicating about the presence of a
second minor set of faults and complexity of deformation. In this setting,
Maino-02 well was drilled with the primary target as B-Sands of Lower Goru
Formation belonging to Lower Cretaceous age while secondary target was A-Sands
of Lower Goru belonging to the same age. The result of the petrophysical
analysis supports two potential zones (zone 1 and zone 2) within the Lower Goru
Formation. Potential reservoir zones were marked with average hydrocarbon
saturation of zone 1 calculated as 63.5% and that of zone 2 as 68.9%.