Digging Deeper with Lee Esch

Salt welds form due to salt thinning by mechanical (e.g., salt-flow) and/or chemical (e.g., salt-dissolution) processes. This webinar explores how we use 3-D seismic reflection, borehole, and biostratigraphic data to constrain the thickness and composition of salt welds, and to test the predictions of analytical models for salt welding.

Author(s): Xavier Moonan (presenter), Connie McLaren, Lynn Anderson, Touchstone Exploration Touchstone Exploration is the operator of the 184 sq km Ortoire Block onshore south eastern Trinidad. Structurally the block covers the open east facing Ortoire Syncline which entails Late Miocene Lower Cruse to Pleistocene Mayaro Fm deltaic fill. These passive fordeep infill deposits sit conformably onto a south easterly verging Early to Middle Miocene fold belt. As such throughout the breadth of the Ortoire Block there are numerous tear fault dissected WSW to ENE trending anticlines. These anticlines were the result of the oblique collision between the northern margin of the South American plate with the leading edge of the Caribbean Plate culminating in the Middle Miocene. Historical exploration within the area by United British Oilfields of Trinidad (UBOT) and Shell, had been focussed on Middle Miocene Herrera amalgamated channelised slope to base of slope deepwater turbidites of the Cipero Formation and Late Miocene Lower Cruse base of slope sheet like turbidite fans. Considered shallow water deposits at the time, the results of many of those wells were considered disappointing or uncommercial. Mapping on various 3D seismic surveys and numerous 2D seismic lines, integrated with surface geology, regional well data and fold and thrust belt models have revealed numerous Middle Miocene Herrera plays within the block. From north to south, Touchstone Exploration has identified an eastern extension of the prolific Penal Barrackpore oilfield in the Cascadura area, a subthrust north verging anticline at Coho, a south easterly verging subthrust anticline at Royston and an eastern extension of the Carapal Ridge north verging subthrust anticline in the Chinook area. Two of these structures, Coho and Cascadura have been successfully explored todate by Touchstone Exploration. At COHO-1 and CAS-1 ST1, extended tests have been completed and commercial discovery notifications have been submitted to the Ministry of Energy and Energy Industries. Touchstone has spud its 3rd exploration well, Chinook-1 in August 2020 and will then drill CAS Deep-1 to test further thrust sheets in the Cascadura area. Bio: Xavier Moonan, Touchstone Exploration Xavier Moonan is a Senior Geoscientist at Touchstone Exploration in Trinidad & Tobago. He has an MSc. in Structural Geology with Geophysics at the University of Leeds, UK, and was awarded a ‘Top Ten Presentation’ by AAPG for his poster presentation on the Penal Barrackpore Anticline at AAPG ICE Conference in Milan, 2011. He served as the Convener for the 20th Caribbean Geological Conference Trinidad 2015, as Programme Committee Trinidad Representative for AAPG ICE Cartagena, 2013, and as General Co-Chair for AAPG GTW Trinidad 2014, GTW Guyana 2017 and GTW Suriname 2019. Xavier is Vice President of the AAPG Latin America & Caribbean Region. He is a member of the Geological Society of Trinidad & Tobago, the Houston Geological Society and the Society of Petroleum Engineers.

Author(s): Peter Bartok, Bartok Inc. (presenter); Simon Oropeza, Independent Consultant; Charles Campbell, Accel Services Inc. Precambrian Greenstone belt underlies a portion of the Guyana-Suriname Offshore Basin (GSOB) followed by Lower Paleozoic sediments deposited in a back arc setting and folded during the Caledonian and the Alleghenian orogenies. Gravity/magnetics aided in delineating the major tectonic features in the region. The Early Jurassic separation of the Florida Block and South America resulted in normal to attenuated crust followed by oceanic crust. The Atlantic rifting resulted in peri-cratonic rifts extending into central GSOB. New concepts on the tectonics of the region provide the basis for structural analysis of the basin and aided by seismic sequence stratigraphy. Of particular significance is the relationship between the Guyana Shelf, associated with the Waini “Arch” and the Demerara Platform. The transition between the two is being called the “Demerara Trough”. Santonian to Campanian canyons associated with faults/fractures, and linked to major rivers acted as conduits for high quality sand-rich slope and basin floor fans described on paleogeographic maps. The Albian facies of Northern South America are deltaic systems restricted to the platform interior (Stabroek) and carbonates (Potoco) with anoxic conditions. The Cenomanian/Coniacian organic-rich Canje Formation is the main source rock. The Cenomanian/Turonian kitchen was evaluated in detail based on available information, new estimates of thermal conditions and description of overpressure in the region. The revised kitchen and geochemical parameters provide for an estimate of basin’s resource potential. Bio: Peter Bartok, Bartok Inc., Petroskills, University of Houston Peter earned a MSc from the State University of New York at Buffalo, and with 48 years of experience he has published over 25 papers. His past experience includes Texaco (5 years), PDVSA (10 years), BP (10 years) and 23 years as a consultant. Along with working as a consultant at Bartok Inc. and Petroskills, he currently is Adjunct Professor at the University of Houston, where he teaches petroleum geology/geophysics and shale resource assessment. Peter is a member of AAPG, SEG and HGS.