ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymerization. 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..

The microgeometry and transport properties of sedimentary rock.

Abstract: This monograph describes recent progress in modelling the transport properties of sedimentary rock. Statistical descriptions are applied to the pore-space geometry and to the transport processes involving pore fluids. Fractals are used to quantify the pore geometry at length scales shorter than grain size. Percolation theory is applied to fluid flow. The permeability can be expressed in terms of a single effective pore diameter measured from mercury injection capillary pressure. This permeability relation is valid for essentially all porous rock and for a broad class of porous media. Mercury injection provides a powerful caliper of the geometry of a percolation cluster in a pore-space and supplies new information about pore space correlations and dynamics of fluid displacements. The statistical description of fluid transport in porous media has analogues in disordered electronic and magnetic materials. Future work may make substantial use of such analogues to solve more complex problems of direct...

Process and catalyst for producing polyethylene having a broad molecular weight distribution

Abstract: Polyolefins having a broad molecular weight distribution are obtained by polymerizing ethylene or higher alpha-olefins in the presence of a catalyst system comprising two or more metallocenes each having different propagation and termination rate constants and alumoxane.

Interpreting avulsion process from ancient alluvial sequences: Guadalope-Matarranya system (northern Spain) and Wasatch Formation (western Colorado)

Abstract: Alluvial deposits of the Guadalope-Matarranya system (Oligocene, Ebro basin, Spain) and the Wasatch Formation (Eocene, western Colorado), provide time-integrated records of the process of river-channel avulsion. These sequences consist of isolated channel-belt sandstones incised into, and abruptly overlain by, flood-plain siltstones, indicating deposition by avulsive river systems. The geometry and distribution of channel incisions suggest that avulsion was not controlled by tectonics, climate, or base-level changes, but formed by autocyclic processes. Measurements from 221 channel fills in the Guadalope-Matarranya system and 38 from the Wasatch Formation allow us to statistically characterize channel geometries we infer to be associated with establishment and abandonment of individual river avulsions. Paleoflow depths in both systems average 1.4 to 1.6 m. Aggradation height (superelevation) of channel margin levees are, on average, 0.6 and 1.1 times paleoflow depth in the Guadalope-Matarranya and Wasatch systems, respectively. These results are consistent with values from recently avulsed modern rivers and suggest that (1) flow depth is the appropriate parameter against which to scale the critical superelevation necessary for channel avulsion; and (2) the increase in potential energy due to channel perching drives the lateral instability that is needed for avulsion to be successful. Numerous stacked channel fills indicate repeated reoccupation of the same site by avulsing channels. These reoccupation channels indicate that inherited flood-plain topography, here abandoned channel forms, was an important control on the arrival site of newly avulsed channels. Comparison of our results to others suggests two end-member types of avulsion can take place. Incisional avulsion, seen here, is characterized by an early incision phase followed by infilling by migrating bar forms. Aggradational avulsion begins with aggradation followed in time by stream integration into a single downcutting channel. We suggest that the type of avulsion is strongly influenced by whether or not the adjacent flood plain is well or poorly drained. In both cases subsequent aggradation and channel perching increase the chances that some triggering event will lead to avulsion.

Mono-Cp heteroatom containing Group IVB transition metal complexes with MAO: supported catalysts for olefin polymerization

Abstract: The invention is a supported catalyst system including an inert support material, a Group IV B transition metal component and an alumoxane component which may be employed to polymerize olefins to produce a high molecular weight polymer.