Abstract:
The lower Indus Basin has a huge significance and a great potential to produce oil
and gas in Pakistan. To determine its hidden certainties, the present study on Duljan area
has been carried out using advanced techniques of petrophysics, seismic inversion, and
Rock physics modeling. The sands of Lower Goru have been assessed by utilizing a
variety of seismic, well logs, core and field analysis that showed spatial heterogeneity in
composition, making it difficult to discriminate between facies and the kind of fluid
content present in the reservoir interval. In this study, 3D seismic cube has been used
along with the data of two wells i.e., Duljan East-01 and Duljan Re-entry 01 well residing
in that field to evaluate reservoir behavior. Seismic data has been used to delineate the
sub-surface structure which shows that the horst and graben structures were formed by
extensional tectonics in the area. C interval of Lower Goru Formation has been evaluated
as clean intervals of considerable reservoir thickness by using Petrophysics. Elastic
properties such as acoustic impedance, density and velocity from seismic data set have
extracted by applying seismic inversion technique. This technique also has facilitated in
the reliable interpretation of important geological and petrophysical boundaries in the
subsurface by giving acoustic impedance contrast for both ‘A’ and ‘C’ intervals of the
utilized wells. Computation of the set of modelled logs for the reservoir interval of Duljan
area by using rock physics modeling. The rock physics modeling has used various input
parameters i.e., lithology, porosity percentage or fluid content to evaluate reservoir
interval. The resulted models for A and C interval of both wells have been shown good
consistencies between measured and predicted properties for the zone of interest. The
cross-plots generated by rock physics modeling clearly separated and distinguished the
litho-fluid zones such as wet sand interval, gas sand interval and shaly units, with proper
alignment which were not obvious by only using conventional petrophysical cross-plots.
