Technical Expert Session | 23 October 2024

This event is open to GESGB members only and information provided on the registration form will be will be checked on the membership database. Please read through the registration terms and conditions before registering.

Special Introductory Offer

The first 10 GESGB members to email us at events@ges-gb.org.uk will receive £15 off their booking to attend this talk.

If you are interested in becoming a member of GESGB please visit: https://www.ges-gb.org.uk/membership/

The GESGB Technical Expert Sessions Programme is designed for our members and focuses on providing in-depth technical insights on topics previously presented at our conferences.

Date & Time: 23 October 2024 | 17:00-18:00 (UK time)

Speaker: Melissa Johansson, Stag-Geological

Topic: The Fractured Basement of Malaysia – a Comparison with Vietnam

This will be an extended version of the talk Melissa Johansson delivered at the Asia Pacific 2024 Conference.

This event will be hosted online via Zoom. Login details will be sent to registered members 24 hours prior to the event. 

The Fractured Basement of Malaysia – a Comparison with Vietnam

Basement rocks represent important oil and gas reservoirs as well as aquifers in various areas of the world. Such reservoirs include fractured or weathered igneous rocks such as granites and granodiorites as well as metamorphic rocks, either unfoliated such as quartzites or foliated such as gneisses.  Probably the best-known fractured basement play in Vietnam is the giant-size Bach Ho (White Tiger) oil field, with estimated reserves of 1.0 to 1.4 billion barrels recoverable. This large gas discovery in fractured granites in Vietnam triggered several basement exploration projects.  Malaysia’s first basement oil discovery occurred with the drilling of Adang Utara-1 in the southern Malay basin, offshore Terengganu and now many basement plays form part of the Malaysian exploration portfolio.

The goals of a successful exploration and appraisal campaign in basement are to determine the hydraulic permeability and fluid storage capabilities of the rock. These properties can be estimated from measuring the  aperture, abundance, orientation and connectivity of the fracture sets intersected by wellbores.  Fractures with apertures of less than a centimetre are currently below the resolution of most borehole logging tools, except for borehole image logs. However, a large property contrast or a tight cluster of fractures can deflect the low-resolution tool readings making cryptic fractures qualitatively detectable. To investigate the geology of fractures in the subsurface, an ensemble of supporting evidence is accrued through the life cycle of a borehole. Advanced measurements and methodologies for fracture characterisation developed for oil and gas exploration exist and similar methodology can be applied to the currently developing geothermal fields.

Melissa Johansson, Stag-Geological

Dr. Melissa Johansson acquired her Ph.D. with Prof Dorrik. A.V. Stow from the University of Southampton on ‘Deep Water Massive Sandstones. She went on to teach Sedimentology at UNIMAS Borneo for two years at the Faculty of Science before joining Schlumberger in Kuala-Lumpur in 1998. Her career as Principal Sedimentologist spanning 24 years took her around the globe, working in countries such as Malaysia, Brunei, Philippines, Myanmar, Alaska, U.K., Norway, Egypt, Syria, Sudan, Qatar, Yemen and China.

Much of her work involved sedimentological studies, interpreting core, borehole images and integrating petrophysical data in deltaic, shallow marine and deep-water sediments. She has designed unique workflows utilizing drilling data, LWD, Wireline and production data to build both facies and fracture models., utilizing IP, Techlog and Petrel. Dr. Johansson spent 10 years as Principal Sedimentologist for Geode-Energy Ltd. a company specialized in Borehole images and Reservoir Characterisation for both oil/gas, CCS and Geothermal Fields. And she now works for Stag Geological designing barrier location for P&A wells in the North Sea.