Prediction of Geomechanical Properties and Seismic Inversion Analysis of Khipro Area, Thar Platform, Pakistan

Abstract

Khipro field is an important producing field of Pakistan; geographically situated in district Sanghar in Sindh and geologically positioned in Lower Indus Basin. To find trapping mechanism formed by normal faults, seismic interpretation is carried out in fractured reservoir of Cretaceous age. Horst and Grabens are recognized in this field. To typify reservoir quality, Petrophysical evaluation have been employed. Results are up to the mark for reservoir zone i.e. Basal Sand with medium to low shale volumes possessing high values of effective porosity and low water saturation. Seismic inversion aimed to extrapolate the quantified inverted parameters beyond the vicinity of well point. Post stack inversion techniques are used to verify the interpretation reliability, reservoir quantification and pore pressure estimation. Post stack inversion algorithms of Sparse spike and Model based are implemented to see their relative outputs. Well stability during Borehole drilling costs 8$ billion roughly in oil and gas sector worldwide. Therefore an evaluation of formation pressure and fracture gradient before drilling an exploratory well, help oil companies to handle their capital resources in a better way. Pore pressure prediction is an important tool contributes in risk analysis before discovering hydrocarbons. Estimating pore pressure in formation helps all shareholders to design a better strategy which ensure well control during exploration activities. The dissertation focuses on prediction of pore pressure, overpressure and under-pressure by applying Eaton’s and Bowers methods using log data of Khipro boreholes and extrapolating these estimates on seismic section using inverted parameters. Some over-pressured zones are found in wells Naimat-Basal-01 and Siraj-south-01 whereas mostly normal pressure prevailed in the study area. In situ stresses formed the basis for unconventional reservoir