Permanent Alteration of Porous Media Wettability from Liquid-Wetting to Intermediate Gas-Wetting

Wettability of Berea and low permeability reservoir rocks are permanently altered from liquid-wetting to intermediate gas-wetting. We use water and decane as model liquid, and air and nitrogen as model gas in the experiments. New chemicals with various functional groups are used in the wettability alteration. We perform compositional analyses of the treated chemical solutions extracted from rock treatment by gas chromatography–mass spectrometry (GCMS) and by inductively coupled plasma-mass spectrometry (ICPMS). The analyses demonstrate reaction between the chemicals and the rock substrate. There is no measurable change in permeability from the chemical reaction for the low molecular weight chemicals. The results reveal the permanent alteration of wettability. Tests are conducted to measure contact angle, spontaneous imbibition, and flow to assess the effect of wettability alteration on flow performance as a function of chemical concentration and functionality. For Berea, the contact angle for the water–air–rock is altered from 0° to ~150° depending on the chemical concentration. For the reservoir rock, the contact angle is altered from ~70° to ~130°. As a result of the treatment, the water flow rate may increase two and a half times for a given pressure drop in the Berea. The permanent alteration of wettability with the new chemicals is intended for prevention of water blocking in gas production from tight reservoirs. Instead of hydraulic fracturing when water is introduced in formations with most of the water retained by the water-wet rocks, one may use the new chemical surfactants in fracturing to avoid water retention for high gas well productivity.     

Zum Nachweis reduzierender Zucker

Ohne Zusammenfassung     

Fuzzy multiple level programming

The use of fuzzy set concept to overcome the computational difficulties of multi-level optimization for large systems appears to be a powerful approach and can solve practical large problems in a very simplified manner. Furthermore, unlike the duo-ploy or multi-ploy approaches, the proposed interactive concept provides flexibility, which is essential due to the different styles of management in different organizations. The approach is formulated based on exploring the fuzziness or indefiniteness, which is almost always present in a decentralized large hierarchy organization. The advantage of this approach is that, not only the problem is much more simplified for solution purposes, the original problem is also much more realistically represented.     

Eiweissstoffe

Ohne Zusammenfassung     

Universal Groups of Effect Spaces

Various axiomatic models for unsharp quantum measurements are investigated. These include effect spaces (E-spaces), effect test spaces (E-test spaces), effect algebras, and test groups. It is shown that a test group G is the universal group of an E-test space if and only if G is strongly atomistic. It follows that if G is strongly atomistic, then G is an interpolation group. We then demonstrate that if G is an interpolation group, then G is the universal group of an E-space. Finally, it is shown that an E-space is isomorphic to an E-test space if and only if it is strongly atomistic.     

Structure-inheriting solid-state reactions under hydrothermal conditions

We have explored several structure-inheriting solid-state reactions (SISSRs) under hydrothermal conditions for syntheses in the Co-Mo-O system. And we found an interesting hydrothermal SISSR from CoMoO₄·3/4H₂O to high-pressure (hp-) phase of CoMoO₄, which enabled us to considerably reduce the severe conditions for the synthesis of hp-CoMoO₄. As similar hydrothermal SISSRs are expected to be useful tools for material syntheses, we also briefly discuss them as a means of developing novel material syntheses and designs.