Abstract:
A source rock has the ability of generating hydrocarbons after the maturation
of the organic component for a specific period of time. In this research work, Chichali
Formation of Cretaceous age is considered to be a potential source rock in the Upper
Indus Basin on the basis of results obtained from conventional petrophysical analysis
of wells Chanda-01, Chanda Deep-01 and Chanda-02 along with the geochemical
analysis of outcrop samples. Faults and horizons are marked on only two lines using
forwarding modeling due to poor resolution of seismic data.
Interpretation has been carried by using the conventional log data. The
interpretation depict that the lower portion of the formation encountered in all the
wells is possibly deposited in anoxic conditions containing sufficient organic content.
Petrophysical assessment includes computation of mineralogy and evaluation of
source rock potential of Chichali Formation. DlogR method is employed in which
porosity and resistivity logs are used for the demarcation of source and non-source
intervals. A continuous profile of total organic carbon content in weight % (TOC) is
created. Seven outcrop samples have been taken into account for TOC, REP and VR
analysis. The analytical results of the outcrop samples revealed that they have
generally good Total Organic Carbon (TOC values ranging between 1 & 2 %) which
shows that shale in this particular area has fair to good source potential. The TOC
results obtained from geochemical analysis complements the results obtained from the
petrophysical analysis. Rock Eval results indicates all of the samples consist of Type
III kerogen which are capable of generating gas at suitable temperature and depth.
Thermal maturity modeling of all wells has been carried out by the geological
input including well log data and literature knowledge. The results of 1D maturity
modeling and burial history show that there is considerable thickness of the overlying
rocks and temperature making Chichali Formation mature enough for hydrocarbon
generation. Therefore, having fair source rock potential and maturity in Chanda gas
field, there is a possibility that Chichali Formation could act as a potential source in
the other fields of Upper and Middle Indus basin and a prospect for the Shale gas
resource as well.
