Natural and Experimentally-Simulated Stylolitic Porosity in Carbonate Rocks

The natural occurrence of stylolitic porosity was studied by the detailed petrographic analysis of Lower Permian Wolfcamp limestones. Based on the observed, natural vertical succession of the microfacies and on the petrographic study of thin sections, an ideal, shallowing-upward sequence was derived, and from it a horizontal model was constructed. The latter consists of three microfacies in terms of depositional environments as follows: bioturbated calcisiltite (intermound); matrix-supported, phylloid algal calcarenite (mound flank); and a grain-supported, phylloid algal calcarenite (mound crest). The crest of this phylloid algal mound was deposited at or slightly above wave base. Two major diagenetic events were revealed. The first was exposure in a freshwater vadose environment and the second was deep burial. Existing reservoir porosity is primarily the result of late diagenetic dissolution and strongly stylolite-controlled. Dissolution along stylolite seams resulted in the formation of several pore types including well developed, suture-like, stylolitic pores, lamellar stylolitic pores, moldic and moldic-enlarged pores adjacent to stylolites, interparticle pores adjacent to stylolites, and vuggy, nonfabric selective pores which often crosscut the stylolites. In contrast, interstylolitic areas are consistently nonporous. Stylolitic porosity is best developed in sutured, high amplitude stylolites with no or little insoluble residue.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Geology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Von Bergen, Donald

Contributors dc:contributor

• Carozzi, Albert V.

• Geology

Identifier

(UMI)AAI8908881

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/72511