The Penyu basin is a transtensional-transpressional basin that developed approximately coeval to the greater Malay Basin to the north. In spite of the stratigraphic and structural similarities of these basins, Penyu basin has had marginal results in terms of discovered volumes of hydrocarbons, and no commercial discoveries yet made on the Malaysian side of the basin. Conventional industry wisdom has attributed this largely to source rock leanness, most likely consisting of lacustrine-type sediments as isolated pods in the deeper portions of half grabens. Poor drilling results since the early 70’s and the elusive nature of this uncalibrated source rock has kept explorers out of Penyu in recent years. Nevertheless, straddling the Malay- Penyu basin is the largest field discovered thus far: the ~350-400 mmbo Belida field. Belida is distinctive in many ways: it consists of a mildly inverted structure sitting on a basement ridge that separates Malay from Penyu basin, it is not underpinned by source rock, thus relying on long distance migration, and has a distinctive oil signature that can be linked to a possibly significant contribution from a Penyu source. In addition, the Rhu oil discovery indicates that there is a working petroleum system within Penyu itself. Post drill analysis, 3D maturation-migration modeling and detailed structural geology suggests that drilling failure in the Penyu basin may be attributable primarily to the following reasons: structural timing versus peak HC generation, trap preservation (especially on the Indonesian side of the basin), trap definition -not one single well has been drilled using 3D data- and migration- given the likely anisotropic character of the carrier beds. Therefore, even though Penyu Basin has a seemingly less abundant petroleum system than the Malay basin, we sense that of all the perceived risks outlined above, only source rock presence and quality may not be derisked ahead of the drill bit. From our regional studies, there are a multiplicity of plays to be tested independently; and the use of 3D seismic as a key exploration tool is required to test once and for all the prospectivity of the Penyu basin.
Thailand's offshore Tertiary basins have yielded nearly five BBOE. Exploration initiated in the 1970s and peaked by mid 1990s. Volumetrically the discoveries are dominantly gas (∼80%). Some important discoveries within the northern Pattani Basin have significant oil reserves e.g. Jasmine 60 MMBO. Basins offshore Thailand consist of Eocene-Oligocene NW-SE grabens, overprinted by narrow N-S fault depocenters developed during Miocene back-arc stretching of continental Sundaland crust. These are filled by lower synrift lake/fluvial deposits, post rift fluvial sequences and drowning brackish intertidal to marine succession. Hydrocarbons are sourced from synrift lacustrine shales. Internally the basins are heavily dissected and compartmentalized by faulting generating numerous traps; consequently, exploration targets have consisted primarily of structural traps. With the exception of the disputed boundary zone straddling Thailand / Cambodian waters exploration offshore Thailand is considered to be in a mature stage of exploration. Nevertheless, fields currently being developed reveal a level of complexity that suggest significant additional exploration upside: complex trapping mechanisms related to combined structural and stratigraphic elements rarely targeted in past ventures. We present a rejuvenated play portfolio for offshore Thailand, within the context of a regional structural and biostratigraphic recalibration. In addition, we illustrate examples of several complex play-trap systems that we consider still worth significant exploration potential. Our view is that Thailand's perception of exploration maturity may be more related to the operational approach taken till now to finding hydrocarbons, rather than actual depletion of the resource. Current “exploration maturity” is related to old ideas and innovative complex / subtle trapping models and play-types as presented here should generate a step-change in the gulf of Thailand creaming curve.
Abstract Exploration in Thailand's offshore Tertiary basins is hampered by the perception that the exploration efforts have reached a mature stage and by increased difficulties related to environmental approvals and stakeholder relations. Petroleum activities in Mubadala Petroleum's concessions in the GoT, although not situated close to the coast, are subject to review by a wide range of stakeholders, including coastal communities, local and national administrations and institutions, and NGO's. At the same time technical work has revealed the possibility of exploration upside, but proving this potential, in addition to the nearly 7.5 BBOE already found, depends on a license to operate and therefore CSR approach and execution are key. We will demonstrate that, while developing a prospect inventory based on innovative play types and complex/subtle trapping models, with combined structural and stratigraphic elements, we also developed a timely, clear and transparent CSR approach, which focuses on local needs combined with active stakeholder engagement by working in partnership with communities, local administrations and organizations on a tiered, repeatable and sustainable long-term footing. There is strong and genuine synergy between an exploration agenda which focusses on play and trap types away from the conventional faulted 3-way in heavily dissected and compartementalised traps concept, and CSR partnering initiatives. Failure to focus on both is restrictive and disadvantageous as they are genuinely complementary. In our view Thailand's perception of exploration maturity may be more related to the operational approach to finding hydrocarbons, rather than actual depletion of the resource. We will illustrate the exploration potential with a regional and biostratigraphic recalibration and with examples of complex play-trap systems and will demonstrate how we are successfully engaging with coastal communities and institutions to address socio-economic, educational and environmental challenges facing the communities around our operations in the GoT.
