Meet the Team

  • John Voon  is an accomplished explorer with 31 years’ experience in the Upstream oil and gas industry of which 26 years are with Shell in various managerial and technical roles including Asia-Pacific New Venture Manager, Area Exploration Manager, Global Technology consultant and Deepwater Exploration Manager. John was pioneer in deepwater exploration success in Sabah, Malaysia.  He has proven track record of delivery in exploration, business development and M&A.  John possesses strong networking among NOCs in Asia.  He has a MS degree in Petroleum Geology from Curtin University, Australia.
  • Allan Scardina was most recently Acquisitions GM for Shell’s Global Exploration organization, where he was a member of the BG deal team and, post-deal closure, he led the exploration portfolio integration effort of the two companies.  In a 36-year career focused on Asia and sub-Saharan Africa, Allan has been directly responsible for several new play discoveries, led successful appraisal campaigns, and led teams for new basin entries and divestments / farm-down efforts. Roles have included regional exploration manager, new business chief geologist and opportunity manager. In addition to Shell, he spent time at Santa Fe Energy and Devon Energy, where he was Head of International NBD. Allan has a MS degree in Geology and an MBA, is a licensed professional Geoscientist in the State of Texas and is a member of AAPG, PESGB, SEAPEX, HGS and SPE.

In addition to the founding members, VGS and Associates has a large team of technical, economic and commercial specialist (the “associates”) that are available as per project requirements.

  • Herman DARMAN, an exploration geoscientist with 24 years of experience and 20 of those years he spent with Shell in several locations such as Indonesia, Brunei, Malaysia and the Netherlands. In his early career Herman worked as a field geologist and in the last few years he worked as principal geocientist to lead many regional studies to identify and screen exploration opportunities in Southeast and Central Asia. He provides training on Play Based Exploration, core evaluation, petroleum geology of Southeast Asia and also lead field trips in the region. Holding a MS degree in Petroleum Geology, Herman is also a certified petroleum geologist of AAPG, a life member of GSM, a co-founder of FOSI and a member of IPA and IAGI.


  • Frank GLASS is an experienced exploration Geoscientist, who has filled several different subsurface evaluation roles in hydrocarbon exploration and development teams during his 27 year career with Shell International. He worked at various locations, including the United Kingdom, the Netherlands, Australia, the United States and recently in Malaysia. He is considered a technical expert in the field of risk and volumetric assessments of exploration prospects, oil and gas prospect generation and evaluation, play-based exploration methods, geophysical data integration and advanced seismic interpretation methods. He has been a long time member of the PESGB, PESA, AAPG EAEG and SEAPEX and holds a masters degree in Structural Geology from the University of Amsterdam.


  • Jason JEREMIAH is a recognized specialist in integrated play evaluation and for his ability to translate subsurface evaluations into project value.  Jason’s expertise stems from his 25 years of experience in petroleum exploration and development. In his most recent positions as subsurface team leader, he and his team accurately defined the subsurface volume and value potential of the Santos Pre-salt basin for Shell E&P, leading to a competitive and successful bid round application.  In addition to Brazil, Jason has led teams both in establishing new country entries and heartland growth along the Atlantic and Caribbean margins (Colombia Deepwater, Argentina unconventionals, Gabon Presalt and West of Shetlands) where he was team leader and Principal Regional Geologist. Jason has a Masters degree in Stratigraphy from University College London. He is a member of AAPG, PESGB and Research Associate for University of Manchester, England and University of Mexico City (UNAM).


  • Mike LENNANE is petroleum explorationist with 25 years’ experience in the oil and gas industry including specialist skills in seismic  interpretation having evaluated major petrolific basins in SE Asia, Australasia and Southern Asia. Undertaken roles from small operating companies through to large multinationals. Excellent understanding of the complete G&G processes from business development, new ventures, regional PBE evaluations, exploration, and appraisal to development. Passionate lead geoscientist with excellent ability to build trust, communicate, listen and present to inspire technical excellence. Proven ability to complete evaluations on time, on budget and achieving goals.


  • Calum MACDONALD has 28 years of experience as a geophysicist with Shell. He is recognised as an expert in basin evaluation and has a unique combination of geophysical and geological knowledge. In is his recent positions has demonstrated his versatility by performing detailed Quantitative Interpretation evaluations for Shell Alaska and then moving to regional basin evaluation for the Americas New Ventures group. Calum has worked on successful bid round and farm in projects in basins all over the globe as a technical lead for global New Ventures. In addition to technical evaluations, Calum is the author of Shell’s Play Based Exploration manual and teacher of the PBE training course. Calum has a PhD in geophysics from the University of California, Los Angeles and is a member of the SEG and PESGB.


  • Michael NOSIARA is a recognized specialist in petroleum systems analysis and integrated play evaluation and for his ability to derisk critical play elements in order to add value to the play portfolio. Michael’s experience stems from his 35 years in petroleum exploration and development, covering projects in over 30 countries and across all 5 continents. In his most recent position as Regional Exploration Manager for the Gulf of Mexico for Hess, he and his team were responsible for evaluating the new Cretaceous play in that basin, resulting in successful acreage capture and a dominant position for the company in that play. In addition, he designed and ran a number of 3 day Play Based Exploration training courses for Hess, which all exploration staff were required to take and substantially changed company culture with regard to how regional evaluations were conducted. Prior to his 6 years with Hess, he was the Head of Basin Modeling for Shell globally, responsible for reviewing all significant petroleum systems evaluations, setting research directions and directing in-house training. Michael has an Honors degree from the University of Melbourne and is a member of AAPG.


  • David PRESCOTT is an experienced petroleum geoscientist who worked for over 25 years with major operating companies (Shell, Hess, Occidental and BHP).  He is recognized for his objective evaluations, with an emphasis on using the full range of exploration geoscience techniques, from play-based exploration processes through to detailed prospect analysis, to arrive at fully integrated solutions.  He has enjoyed notable success in opportunity capture, through both competitive bid rounds and asset purchases.  In his last position at BHP, David lead a small team conducting a complete re-working of the hydrocarbon charge history of the mature Gippsland Basin, to better understand the basin’s remaining prospectivity. Since leaving BHP, David has provided exploration evaluation services through his own consultancy.  David has worked in many of the countries bordering the South China Sea, in the Middle East, and on deep-water projects in NW Europe and West Africa. He was educated in the U.K. (B.Sc. Durham, Ph.D. Oxford) and is a member of the AAPG, PESGB and SEAPEX.


  • Tomas VAN HOEK has held a variety of technical subsurface and team lead roles during his 16-year career with Shell International and Roc Oil while on postings in the Netherlands, Malaysia, and China. During this time, he worked on the revitalization of the Shell Malaysia portfolio (resulting in a number of significant discoveries), conducted a large number of high-impact subsurface studies across the Shell global portfolio and developed new seismic interpretation technology (invented 3 patented, novel seismic attributes). Roles included technical lead for Shell Malaysia deep water, senior geoscientist, and research geologist. In his most recent position as technical team lead for Roc Oil, Tomas was instrumental in the signing of two new PSC’s, successful acreage divestment and execution of a substantial exploration program. Tomas is a recognized technical expert in the fields of seismic interpretation, prospect evaluation, prospect risking & volumetric assessment and petroleum systems analysis. He was co-founder and instructor of the Shell Advanced Petroleum Systems Analysis field course. Tomas earned his Masters degree in Geology from the University of Amsterdam.


  • Vicky YAWAPONGSIRI  has 18 years of experience in oil and gas industry with a focus economic valuation, fiscal regime, oil and gas development plan, gas commercialization option, new country entry, business development, contract negotiations and due diligence.  She joined ConocoPhillips in Houston in 1999 and relocated with the company to Indonesia, Australia and Singapore.  She is currently working as a consultant at Twinza Oil.  She has worked on various oil and gas upstream and midstream projects in Vietnam, Indonesia, Malaysia, Cambodia, Myanmar, Bangladesh, East Timor, Australia and Thailand.Vicky has an MBA from Carnegie Mellon University and a Bachelor in Industrial Engineering from Chulalongkorn University.  She is also a Chartered Financial Analyst charterholder.