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Abstract: Trap and Seal Analysis — Concepts and Mexican Examples
Results of the application of a methodology of trap and seal analysis to pre- and post-drill cases are presented. The methodology is applied to risk exploratory prospects and to evaluate the trap and seal elements. Furthermore, this methodology is used in the post-drilling analysis to determine the controls affecting the distribution of the fluid columns in the well-tested traps.
The methodology covers four steps in general: 1) quality control of maps that describe the traps, 2) juxtaposition analysis, 3) capillary seal capacity analysis and 4) mechanical seal capacity analysis.
Two post-drilling examples are presented. The first one is an onshore oil field located in the Salina del Istmo Basin, which consists of a fault-dependent trap; the element controlling the trap fill will be shown to be a sand-on-sand juxtaposition (cross-fault leak) between two blocks. The second one is an offshore light-oil producing well in the Catemaco thrust and fold belt; two untested seismic amplitude anomalies were analyzed with the methodology, and the possible hydrocarbon columns would be controlled by cross-fault leak with minor participation of the capillary seal capacity.
Likewise, two offshore pre-drilling examples are presented, both of them are located in the Catemaco fold bend belt. The first one is a faulted anticline with a conformable seismic amplitude anomaly. The methodology shows that it has not reached the top seal capacity and the trap should be filled to its spill-point. The second example is a fault-dependent trap, with a conformable seismic amplitude. This trap is limited by two faults, both of them might have cross-fault leak controlling the possible hydrocarbon column.
Acknowledgments and Associated Footnotes
1 Pemex Exploracion y Produccion, Activo Integral Veracruz
2 Pemex Exploracion y Produccion, Activo Regional de Exploracion Region Sur
3 Pemex Exploracion y Produccion, Activo Regional de Exploracion Marina
4 ExxonMobil Exploration Co.
Copyright © 2007 by The Gulf Coast Association of Geological Societies