Modelling and Mapping of Thermal and Geochemical Parameters in Mexican and Japanese Deep Waters

Harald R. Karg¹ and Demetrio M. Santamaria Orozco^2
1IES Integrated Exploration Systems, Villahermosa, Mexico
²Instituto Mexicano de Petroleo, Mexico City, Mexico

An integrated workflow is presented where 3D Petroleum Systems Modeling in combination with geochemical and statistical methods are employed to provide pre-drill reconnaissance to mitigate exploration risks in deep water provinces. Case studies from the Gulf of Mexico and the Japan Sea are shown.

Delineation of exploration potentials and assessment of geologic uncertainties and risks as well as mapping of source rock and fluid parameters beyond drilling and seismic coverage are the primary objectives. Temperature and heat flow maps, maturity, potential fluid properties (phase, GOR, API), and subsurface pressure are the final products of the procedure.

A key element of the work flow is the establishment of a conceptual thermal and geometric 3D model, based on heat flow data, top crust maps, sediment isopachs and bathymetry, followed by the geologic and petrophysical definition of individual stratigraphic units. For calibration, heat flow measurements and source rock data from shallow water exploration wells and deep water ODP drill holes were used. Calibration parameters were obtained through bulk geochemical methods and standard kerogen analysis, source rock pyrolysis and organic petrography. Application of statistical methods in the modeling package allows the determination and mapping of uncertainty ranges of individual parameters, for example isotherms or the regional extent of particular maturity intervals within denominated source intervals.

The presented workflow, based on dynamic 3D geologic models, provides essential elements for quantitative risk evaluation of unexplored deep water petroleum systems. Significant new exploration potential can be outlined in both study areas, with additional source potential predicted for the Japan Sea due to high geothermal gradients.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas