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..

Long Chain Branched Isotactic Polypropylene

Abstract: Long chain branched isotactic polypropylene (LCB-PP) was synthesized using metallocene catalyst (rac-dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride activated by methylaluminoxane). The branching was in situ generated in a diluted polymerization condition using hexane or toluene as diluent. The polymers have a significant population of branched molecules as evidenced by multiangle laser light scattering analysis. More importantly, such a branching structure in isotactic polypropylene has been, for the first time, identified by 13C NMR spectroscopy. The 13C NMR resonance assignments of the branching structure are based on the model polymer characterization, stereo environment analysis, and chemical shift calculation. The unique stereo environment of the branching structure provides insight into the mechanism of LCB formation in such isotactic polypropylenes. The branching levels determined by 13C NMR are directionally consistent with that estimated from laser light scattering analysis.

Acid gas disposal method

Abstract: This invention is method of recovering gas from a gas-bearing subterranean formation (11) in which gas is produced from an upper portion of the formation (11) and a waste gas is injected into a lower portion of the formation (11) to dispose. The waste gas is injected within a 3000 ft (914 m) radial distance from the production of the gas. The injection and production can be carried out using one well or a plurality of wells.

Model for the fingering instability of spreading surfactant drops

Abstract: We show that the Marangoni effect drives the fingering instability observed at the edge of an aqueous surfactant drop spreading on a thin film of water. A calculation of the unperturbed flow profile demonstrates that the spreading of the drop is controlled by the dynamics of a thin layer which develops in front of the drop. The surface-tension gradient in this region leads to the fingering instability via a mechanism mathematically similar to that in Hele-Shaw flow despite the very different underlying physics.

Quantitative Determination of the Mechanical Properties of Shales

Abstract: Shales make up more than 75% of drilled formations and cause at least 90% of wellbore-stability problems. Physical measurements of shale properties are required to develop realistic constitutive relationships and to understand and define shale strength and behavior under downhole conditions. Quantitative shale-strength data are needed to improve wellbore-stability model predictions. This paper describes a research test program to determine the mechanical properties of different classes of shales and to build a database on their characteristics and mechanical behavior. Shale samples from undisturbed block samples were prepared under controlled conditions. Mechanical test techniques were developed to measure effective-stress/strain properties accurately for shales. The tests require a heavy-duty, triaxial test load frame and other specially designed equipment to obtain precise pore pressure measurements. During the tests, pore pressure, stresses, and strains were monitored accurately by an automatic data-acquisition system. The test techniques described can be used to test shales with different characteristics: soft, hard, brittle, plastic, etc. On the basis on results of several shale tests, high-quality, effective-stress/strain data and failure criteria (shale strength relationships) can be obtained routinely.

Method for utilizing triethylaluminum to prepare an alumoxane support for an active metallocene catalyst

Abstract: of EP0368644This invention relates to a process for preparing a supported metallocene alumoxane catalyst for use in the polymerization of olefins. The invention particularly relates to the use of silica gel containing from about 6 to about 20 per cent by weight adsorbed water as the catalyst support material. It has been found that such silica gel may be safely added to a solution, of trialkylaluminum to form by direct reaction with the adsorbed water content of the silica gel catalyst support material the majority of the alumoxane component requirement of the catalyst system. An alkylalumoxane coated silica gel is formed to which a trimethylaluminum treated metallocene may be added and the resulting material dried to free-flowing powder. The dry free flowing powder may then be used as a supported metallocene alumoxane catalyst complex for gas phase or liquid phase polymerization of olefins. The supported catalyst produced by such procedure has an activity at least comparable to a catalyst of similar composition which is produced exclusively with trimethylaluminum as the alumoxane forming aluminum alkyl.