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Marathon Oil Corporation is a United States-based oil and natural gas exploration and production company. Principal exploration activities are in the United States, Norway, Equatorial Guinea, Poland, Angola and Iraqi Kurdistan. Principal production activities are in the United States, the United Kingdom, Norway, and Equatorial Guinea. Within the United States, Marathon Oil has recently focused development efforts on liquids-rich shale plays, including the Bakken and Eagle Ford formations. Marathon Oil owns interests developing Athabasca oil sands resources and in Waha Oil Company . Marathon's headquarters facility is the Marathon Oil Tower in Houston, Texas. Wikipedia.

Grechka V.,Marathon Oil
Geophysics | Year: 2015

A recently published analytic technique for computing locations of microseismic events jointly with velocities of homogeneous isotropic media was extended to surface microseismic monitoring and transversely isotropic models with tilted symmetry axes (TTI). The analysis of traveltimes of the direct P-, SV-, and SH-waves, conducted under the assumptions of homogeneity and weak anisotropy, indicated that the SV-wave data acquired in modern wide-azimuth surface microseismic surveys yield uniquely solvable joint inverse problems for an arbitrary symmetry-axis tilt, whereas the tilts should be close to 90° from the vertical for the P-waves propagating in anelliptically anisotropic media and strictly equal to 90° for the SH-waves to maintain the uniqueness of the joint inversion. These theoretical findings, confirmed on ray-tracing synthetic, were applied to a field microseismic data set. The P-waves excited by microseismic events were found to exhibit significantly flatter moveouts and better focused stacks when located in a constructed effective TTI model compared to those located in a horizontally layered isotropic model provided as a part of conventional microseismic service. © 2015 Society of Exploration Geophysicists.

Grechka V.,Marathon Oil
Geophysics | Year: 2013

Two-point ray tracing in anisotropic media requires the group and phase velocities to be calculated along ray directions available at each step of a ray bending algorithm. This computation, usually done iteratively or through velocity tables, becomes exceedingly involved for shear-waves that have multivalued group-velocity surfaces, such as in the presence of triplications on the SV wavefronts in vertically transversely isotropic (VTI) media. The difficulties encountered in computing the SV-wave velocities for a given ray direction can be circumvented by solving a polynomial equation whose real-valued roots provide the phase directions of the P- and either one or three SV-waves propagating along a selected ray; those phase directions then allow the group and phase velocities to be computed in a standard fashion. I construct the polynomial and supply computer codes implementing its solution, the codes that can be used in two-point ray-tracing software to improve its performance. © 2012 Society of Exploration Geophysicists.

Grechka V.,Marathon Oil
Geophysics | Year: 2014

Shear waves excited by natural sources constitute a significant part of useful energy recorded in downhole microseismic surveys. In rocks, such as fractured shales, exhibiting symmetries lower than transverse isotropy (TI), the shear wavefronts are always multivalued in certain directions, potentially complicating the data processing and analysis. This paper discusses a basic tool -the computation of the phase and group velocities of all waves propagating along a given ray -that intends to facilitate the understanding of geometries of the shear wavefronts in homogeneous anisotropic media. With this tool, arbitrarily complex group-velocity surfaces can be conveniently analyzed, providing insights into possible challenges to be faced when processing shear waves in anisotropic velocity models that have symmetries lower than TI. Among those challenges are complicated multipathing and the presence of cones of directions, known as internal refraction cones, in which no fast shear waves propagate and the entire shear portion of the body-wave seismic data consists of several branches of the slow shear wavefronts. © 2014 Society of Exploration Geophysicists.

Royal Dutch Shell, Chevron and Marathon Oil | Date: 2014-12-17

The present invention provides a method for extracting bitumen from an aged oil sands ore stream, the method comprising at least the steps of:

Royal Dutch Shell, Chevron and Marathon Oil | Date: 2014-11-06

The present invention provides a method of filtering a solvent-containing slurry stream including: (a) providing a solvent-containing slurry stream, the solvent comprising an aliphatic hydrocarbon; (b) depositing the solvent-containing slurry stream provided in step (a) as a filter cake on a filter medium, wherein a top layer of liquid is formed on the filter cake; (c) allowing the top layer of liquid as formed in step (b) to drain through the filter cake such that substantially no liquid remains on top of the filter cake; (d) allowing a gas to partially penetrate into the filter cake thereby obtaining a filter cake with a liquid solvent-depleted top layer; (e) passing liquid solvent through the filter cake with the liquid solvent-depleted top layer as obtained in step (d) thereby obtaining a washed filter cake; (f) removing solvent from the washed filter cake as obtained in step (e) thereby obtaining a solvent-depleted filter cake; and (g) removing the solvent-depleted filter cake as obtained in step (f) from the filter medium.

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