Geological, Geophysical and Geochemical Analysis for the Assessment of Source Rock Potential of Chichali Formation, Upper Indus Basin, Pakistan (T-1530) (MFN 5821)

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.