Gas-bearing sands appraisal through inverted elastic attributes assisted with PNN approximation of petrophysical properties

DOI: 10.48129/kjs.15915

Authors

  • Zahid Ullah Khan Department of Earth Sciences, Quaid-I-Azam University
  • Mona Lisa Department of Earth Sciences Quaid-I-Azam University Islamabad Pakistan
  • Muyyassar Hussain Principal Geoscientist, LMK Resources, Ufone Tower, 9th floor, Jinnah Ave, Block J F-7/1 Blue Area, Islamabad, Pakistan.
  • Syed Adnan Ahmed Sr. Geoscientist, LMK Resources, Ufone Tower, 9th floor, Jinnah Ave, Block J F-7/1 Blue Area, Islamabad, Pakistan.

DOI:

https://doi.org/10.48129/kjs.15915

Abstract

The Pab Formation of Zamzama block, lying in the Lower Indus Basin of Pakistan, is a prominent gas-producing sand reservoir. For the optimized production, it is necessary to characterize the gas-sand facies from the rest of the wet-sands and shales of the Pab Formation. Therefore, an approach is adopted based on a relation between petrophysical and elastic properties to delineate the prospect locations. Petro-elastic models for the identified facies are generated to discriminate lithologies in their elastic ranges. Several elastic properties such as p-impedance (11,600-12,100 m/s*g/cc), s-impedance (7,000-7,330 m/s*g/cc), and Vp/Vs ratio (1.57-1.62) are determined from the simultaneous prestack seismic inversion, which leads towards the identification of gas sands in the field. Further, inverted elastic attributes along with well-based lithologies are integrated into the Bayesian framework to estimate the gas sands probabilities surrounding the drilled well locations. Bulk volumes of PHIE and clay are approximated from elastic volumes trained on well logs through Probabilistic Neural Networking (PNN), which better handle heterogeneity effects. The outcome indicated the channelized gas-sands passing through existing well locations having less clay content with maximum effective porosities of 9%, hence confirming the good quality of the reservoir. Such techniques can be broadly adopted in the producing basins to recognize economic potential zones so that maximum production can be obtained from them.

Author Biographies

Zahid Ullah Khan, Department of Earth Sciences, Quaid-I-Azam University

Zahid Ullah Khan is PH.D scholar in Quaid-I-Azam University, Islamabad and had done his M.Phil. and M.Sc. from similar institute. He remained visiting faculty member in the similar institute and taught various G&G subjects. He also employed in the LMKR, Pakistan and working as Sr. Geoscientist. He remained part of the teams that engaged in national and international projects related to R&D and QI.

Mona Lisa, Department of Earth Sciences Quaid-I-Azam University Islamabad Pakistan

Prof. Dr. Mona Lisa is currently working as a Professor in the Department of Earth Sciences, Quaid-I-Azam University (QAU), Islamabad. She won DAAD Sandwich Fellowship and AvH Fellowship of Germany. She is the first PhD in Earthquake Seismology in Pakistan. Won Pakistan Academy of Sciences (PAS) Gold Medal in Earth Sciences. Regular Associate of International Centre of Theoretical Physics (ICTP), Trieste, Italy. Collaboration with Oregon State University (OSU), USA; University Of Arkansas, USA; Imperial College London, UK; GFZ, Potsdam Germany; ICTP, Italy; IIEES, Tehran, Iran and many other national and international institutes. Published more than 50 research publications and won funding from PSF, HEC and PAS. Served as a Head of Department in COMSATS, Islamabad and as a Chairperson, Department of Earth Sciences, QAU, Islamabad.

Muyyassar Hussain, Principal Geoscientist, LMK Resources, Ufone Tower, 9th floor, Jinnah Ave, Block J F-7/1 Blue Area, Islamabad, Pakistan.

Muyyassar Hussain employed as Principle Geoscientist with LMKR, Pakistan. He has experience of more than 12 years in the petroleum sector and successfully delivered many national and international R&D, QI and unconventional studies. He is visiting faculty member in a couple of universities. He taught various G & G subjects and supervise many students at BS and MS levels. He is currently working on Rock physics modeling and inversion techniques.

Syed Adnan Ahmed, Sr. Geoscientist, LMK Resources, Ufone Tower, 9th floor, Jinnah Ave, Block J F-7/1 Blue Area, Islamabad, Pakistan.

Syed Adnan Ahmad has been working as Sr. Geoscientist with LMKR for 8 years. His responsibilities include Data validation i.e. wells and seismic for quality check on the commercial softwares, software algorithms QC, and client related petroleum workflows. He has done MS in Geophysics from Bahria University, Islamabad, and is currently a PH.D candidate in Earth Sciences, Quaid-I-Azam, University, Islamabad. He remained visiting faculty member in a similar university and taught many G&G subjects.

Published

14-12-2021

Issue

Section

Earth & Environment