ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymer. The organization has 16969 authors who have published 23758 publications receiving 535713 citations. The organization is also known as: Exxon Mobil Corporation & Exxon Mobil Corp..

How clay grain coats inhibit quartz cement and preserve porosity in deeply buried sandstones: Observations and experiments

Abstract: Observations and hydrothermal experiments were used to derive new information about how clay grain coats inhibit quartz cement and preserve porosity in deeply buried sandstones. Samples of deeply buried, porous sandstones with different types of clay coats were split in two, coats removed from one of each pair of splits, and grain surfaces inspected with scanning electron microscopy. Quartz grains in a fluvial-deltaic sandstone buried to 115C had no visible authigenic quartz on grain surfaces cleaned of diagenetic chlorite coats, though well-developed overgrowths occurred on nearby, naturally uncoated grains. However, in similar sandstones buried to 164C, quartz-grain surfaces exposed by chlorite-coat removal were covered with small (5 m), mainly anhedral, syntaxial quartz overgrowths. Similar overgrowths were observed under various detrital and diagenetic clay coats in porous eolian sandstones buried to temperatures up to 215C. We conclude that clay coats may retard quartz nucleation at moderate temperatures, but at high temperatures, many coats permit quartz nucleation and preserve porosity by limiting cement growth. To investigate cement growth-limitation mechanisms, samples with coats removed were subjected to quartz-cementing conditions in a hydrothermal reactor. During experiments, the naturally occurring small overgrowths on clay-cleaned grains coalesced and grew, suggesting that clay particles in coats inhibit cement growth by forming barriers to early-overgrowth coalescence. Although the fraction of grain-surface coverage is the primary control on cement inhibition by coats, cement growth–interference textures vary with coat type, providing a mechanism by which coat composition may be a secondary control on inhibitory effectiveness. In deeply buried sandstones, quartz cement can fill significant microporosity within diagenetic chlorite coats, potentially affecting mechanical and petrophysical rock properties.

Ion Exchange of the Layered Perovskite KCa2Nb3O10 by Protons.

Abstract: The alkali cations in the layered perovskites MCa 2 Nb 3 O 10 (M ≡ K, Rb, Cs) are exchanged by protons in aqueous acid in a topochemical reaction to give HCa 2 Nb 3 O 10 . The unit cell of HCa 2 Nb 3 O 10 , as determined from powder X-ray diffraction, is tetragonal with a = 3.851 A and c = 14.38 A and contains one formula unit. The anhydrous hydrogen compound hydrates to form a composition HCa 2 Nb 3 O 10 ·1.5H 2 O which is also tetragonal with a = 3.854 A and c = 16.23 A . The hydration-dehydration behavior at 24 °C as a function of the partial water pressure shows significant hysteresis as a result of the expansion and contraction of the unit cell along the c axis.

Downhole gas separation method and system

Abstract: A method of separating a multi-component fluid in a wellbore uses at least one fluid separation membrane (21) having a feed side and a permeate side that is incorporated in the wellbore. A flowing stream (16) of the multi-component fluid obtained from a subterranean zone (11) being in fluid communication with the wellbore is passed across the feed side of the membrane (21) at a first pressure. A retentate stream (18) depleted in at least one component compared to the multi-component fluid is withdrawn from the feed side of the membrane (21) and passed to the earth's surface. A permeate stream (17), at a second pressure is withdrawn from the permeate side, in which the permeate stream (17) is enriched in at least one component compared with the multi-component fluid. The second pressure is controlled to maintain the second pressure below the first pressure.

Bioremediation of Marine Oil Spills

Abstract: In the long run, biodegradation is the eventual fate of oil spilled at sea that cannot be collected or burnt. Stimulating this biodegradation is thus an important option for maximizing the removal of oil from the environment, and minimizing the environmental impact of a spill. For handling oil while it is still floating on the sea surface, dispersants are advantageous because they maximize the surface area available for microbial attack, and stimulate biodegradation. If oil beaches on a shoreline, it is likely that biodegradation is limited by nutrients such as nitrogen and phosphorus, and the careful application of fertilizers stimulates the biodegradation of residual beached oil. These approaches epitomize modern environmental technologies; working with natural phenomena to achieve a more rapid clean-up while minimizing undesirable environmental impacts of a spill. For handling oil while it is still floating on the sea surface, dispersants are advantageous because they maximize the surface area available for microbial attack, and stimulate biodegradation. If oil beaches on a shoreline, it is likely that biodegradation is limited by nutrients such as nitrogen and phosphorus, and the careful application of fertilizers stimulates the biodegradation of residual beached oil. These approaches epitomize modern environmental technologies; working with natural phenomena to achieve a more rapid clean-up while minimizing undesirable environmental impacts.

Effects of UV Irradiation and Plasma Treatment on a Polystyrene Surface Studied by IR−Visible Sum Frequency Generation Spectroscopy

Abstract: IR−visible sum frequency generation (SFG) spectroscopy was used to study surface modification of polystyrene by its exposure to a UV light source or plasma. It was found that the polystyrene surface underwent dramatic changes after exposure to these treatments, as evidenced by marked changes in the surface SFG spectra. Before the treatments, the surface spectrum showed a pronounced peak at 3068 cm-1 which is characteristic of the symmetric stretch of the aromatic C−H of polystyrene. This peak decreased markedly, and other vibrational bands associated with the CH2 and CH3 groups appeared after the treatments. The observed spectral changes provided direct evidence of surface reactions involving the aromatic ring. In addition, our data showed that the degrees of oxidation of the polystyrene surface were different with the two processes. The oxidation to a higher oxidation state, resulting in the formation of carbonyl/carboxyl species, was observed with plasma treatment but not with UV irradiation. This diffe...