Crews, Steven G.¹
(1) Anadarko Petroleum, The Woodlands, TX

ABSTRACT: Map-Based Charge Modeling in the Eastern Black Sea, Offshore Georgia

A practical approach to modeling exploration charge risk that is both rapid and comprehensive is proposed and illustrated using a case study from the Georgian sector of the Black Sea. Regional and prospect-scale analyses were conducted; large uncertainties in the values of key parameters such as source-rock depth and heat flow in this undrilled frontier province were addressed using Monte Carlo techniques.
Our approach centers around pseudo-3D models based on high-resolution (typically 10⁵ grid cells) maps of chronostratigraphic surfaces. Burial history and paleostructure are obtained through backstripping. Convolution of the burial history with empirical or theoretical models for vertical and lateral temperature prediction, and with source rock properties, allows simulation of thermal maturity history and predictions of generated and expelled volumes through time. On any map surface, fetch areas can quickly be determined for prospective structures using non-Darcy migration techniques, and the total expelled volumes within each fetch area are calculated by summing the contributions of each grid cell. This process is fast enough to run hundreds or thousands of Monte Carlo realizations, in which the sensitivity to variation in 9 key input parameters is analyzed. Liquid and vapor column heights and leaked or expelled volumes can be predicted for each trap based on estimated reservoir, fluid and seal properties and P-T conditions.
The workflow presented here is enabled by two recent technological developments: (1) increased availability of semi-regional digital map grids based on seismic data; and, (2) dramatic improvements in the performance of personal computer hardware and software. The ability to import and manipulate large data sets, do rapid interactive maturity and flow path modeling, and visualize the model in 3D makes this approach practical, efficient and useful.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.