Role of Self-Organization in Migration and Trapping of Petroleum

Peter Ortoleva

Self-organization is the transformation of a system to a state of higher order without the imposition of a template from the external world. We demonstrate that the coupling of reaction and transport processes during diagenesis can lead to self-organization of patterns of mineralization and petroleum Specifically, the coupling of pressure solution and free-face dissolution to diffusion is shown to lead to the generation of laminated cements and stylolite arrays that may serve as diagenetic traps. Furthermore, such mechanical-chemical coupling during burial can lead to an instability of steady compaction that endures the formation of extensive, horizontal pressure seals. The coupling of reaction and flow through the texture dependence of the Darcy permeability is shown to ead to flow focusing and associated fingered alteration fronts that dramatically alter the pathways of petroleum migration. Finally, methanogenesis coupled with buoyancy may drive kilometer-scale flows.

All the above phenomena are demonstrated via the solution of coupled mass valance, grain growth, and force balance equations. Solution is accomplished via a number of computer codes. Such studies are valuable in assessing conditions (sedimentation rate and chemistry and tectonic history) favoring these phenomena.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.