Porosity enhancement

Lundegard, P.D. Land, L.S. (1986) Carbon dioxide and organic acids their role in porosity enhancement and cementation, Paleogene of the Texas Gulf Coast. In Roles of Organic Matter in Sediment Diagenesis (Ed. Gautier, D.L.), Spec. Publ. Soc. econ. Paleont. Miner., Tulsa, 38, 129-146. 

Surdam, R.C., Jiao, Z.S. MacGowan, D.B. (1993) Redox reactions involving hydrocarbons and mineral oxidants a mechanism for significant porosity enhancement in sandstones. Bull. Am. Ass. petrol. Geol., 77, 1509-1518. 

The best reservoir quality potential expected for the Serraria Formation is in structural blocks in the distal and middle domains affected by porosity enhancement through extensive feldspar and carbonate cement dissolution in connection with the post-rift exposure and telogenetic infl ux of meteoric waters. 

Curtis, C.D. (1983) Geochemistry of porosity enhancement and reduction in clastic sediments. In Petroleum Geochemistry and Exploration of Europe (Ed. Brooks, J.). Spec. Publ. Geol. Soc. London, 12, 113-125. 

Bloch, S., McGowen, J.H. Duncan, J.R. (1990) Porosity enhancement from chert dissolution beneath Neoco-mian unconformity Ivishak Formation, North Slope, Alaska Discussion. Bull. Am. Ass. Petrol. Geol., 74, 85-88. 

Fein, J.B. (1994) Porosity enhancement during clastic diagenesis as a result of aqueous metal-carboxylate complexation experimental studies. Chem. Geol., 115, 263-279. 

Lundegard, P.D. Land, LS. (1986) Carbon dioxide and organic acids their role in porosity enhancement and cementation, Paleogene of the Texas Gulf Coast. In ... 

Significant reduction of mixed-layer days and their further or-d ng latkb improwng crystallinity of Illite and chlorite. Emergence of dikite. Feldspar dissolution. Intens rve carbonate ament leashing (especially dolomite) and predpitation, as well as ferroan carbonates. Quartz pressure srrfution and other all-cate dissolution. Further finten-slve) porosity enhancement. 

Fig. 4.16b. Porosity enhancement and reduction of Paleozoic sediments (Ahnet-Mouydir Basin) due to pressure solution (boreholes stratigraphy and lithology are based on Sonatrach s drilling data)...

Porosity enhances the ability of PVC parhcles to easily release VCM dissolved in polymer, to absorb addihves, such as plashcizer, and to be easily deformable under heat and shear in an extruder. Secondary suspending agents that stabilize internal structure and early terminahon of polymerizahon enhance porosity. 

Increasing amounts of wustite in the precursor are therefore favorable, owing to their porosity-enhancing effect. Above an optimum concentration, however, any further increase in the amount of wustite will be detrimental. This is because a pore system which is too large will separate the individual crystallites of magnetite to such an extent that the fast ion diffusion mechanism is blocked. This, in turn, prevents the formation of intermediate wustite nuclei, resulting in an increase in the activation energy of the bulk reduction. 

Di-n-butyl phthalate Poly(vinyl acetate) (19), porosity enhancing in lithium cells (20), medical nail lacquers (21)... 

The highest specific capacitance of 1510 F/g was currently reported by Subramanian and co-workers using graphene nanolayers synthesized using electrophoretic deposition of graphene, followed by modification with electropolymerized polypyrrole. The composite electrode was highly porous and it is believed that this porosity enhances the electrode interaction with the electrolyte. 

Dielectric constant changes roughly with the square inverse of the bandgap. Dielectric constant drops with solid size or porosity enhancement. 

If this sequence of carbonate reactions is coupled with parallel organic reactions, including generation and decarboxylation of organic acids and acid anions, a predictive, process-oriented model can be constructed for the carbonate reactions. The model consists of three operations (1) interpretation of reaction pathways (2) kinetic modeling of organic reactions and (3) simulation of rock/water interactions in either time or temperature space. Integrating these three operations allows us to predict zones of carbonate dissolution or optimum porosity enhancement (positive porosity anomalies) in source/reservoir rock systems. 

We will evaluate the relationship between carbonate dissolution events, porosity enhancement, and organic acids. 

With continuous and progressive burial, a sandstone enters the intermediate burial zone at approximately 80°C (zone of intense diagenesis, 80 to 110°C Table 1). In this interval, a potential hydrocarbon reservoir accommodates important porosity enhancing reactions early-formed carbonate cements may be dissolved (or later carbonate cements inhibited), and aluminosilicate framework grains (both feldspar and lithic) may be dissolved. Thus, in this zone, porosity can be preserved or significantly enhanced. 

Several porosity-destroying reactions also characterize this zone. For example, late ferroan carbonate cements are potential reaction products in this zone, and may significantly occlude porosity (Boles 1978). Also, there is a wide variety of aluminosilicate reaction products (e.g., kaolinite, illite, chlorite, and quartz) that can form in this zone as a result of aluminosilicate dissolution. The imbalance between porosity-enhancing or-preserving reac-... 

The magnitude of porosity enhancement due to aluminosilicate grain dissolution in a reservoir and source-rock system depends on facies relationships, variations in original composition, formation of subsequent cements, availability of fluid conduits, fluid flux, and the proximity of organic-rich source rocks in hydrologic connection with the reservoir rock. In contrast, carbonate decementation and mass transfer apparently can occur on a scale larger than a specific reservoir and source-rock system (Schultz et al. 1989). 

In summary, acidic formation fluids generated by abiotic sulfate reduction (Table 4) can account for the observed additional dissolution of feldspar, carbonate, and sulfate minerals and the formation of such products as late illite, chlorite, and pyrite in deeply buried (130 to 210°C) clastic systems. The porosity enhancing and preserving potential of these reactions will be directly dependent upon the availability and spatial distribution of hydrocarbons, sulfate, and iron. 

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