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Gushor Inc. | Date: 2012-08-15

Techniques for sampling a subsurface reservoir include lowering a downhole logging tool comprising one or more samplers, a cleaner system, and a sample probe bit into a borehole until at least one sampler is positioned correctly in a subterranean reservoir; advancing the cleaner system into the reservoir cleaning mud filtrate and contaminated reservoir material away into a mud column; advancing the sample probe bit into the reservoir; and solvent is injected into the reservoir from the solvent reservoir.

The invention relates to an apparatus and method to obtain a bitumen or heavy oil sample from an oil reservoir sample, such as a core sample, to enable measurement of physical properties such as viscosity, API gravity, or chemical properties such as sulphur content of the obtained bitumen or heavy oil sample. The analyses performed on the samples obtained in accordance with the invention are effective in assisting oil field operators in making timely drilling and production decisions at the oil reservoir or for routine laboratory extraction of oils and bitumens. The invention also permits the collection of samples from simulated thermal recovery operations and also allows the collection of bitumens and oils for online analysis of live oil physical properties.

Mullins O.C.,Gushor Inc. | Andrews A.B.,Gushor Inc. | Pomerantz A.E.,Gushor Inc. | Dong C.,Gushor Inc. | And 6 more authors.
Proceedings - SPE Annual Technical Conference and Exhibition | Year: 2011

Understanding asphaltene gradients and dynamics of fluids in reservoirs had been greatly hindered by the lack of knowledge of asphaltene nanoscience. Gravitational segregation effects on oil composition, so important in reservoir fluids, are unresolvable without knowledge of (asphaltene) particle size in crude oils. Recently, the "modified Yen model" also known as the Yen-Mullins model, has been proposed describing the dominant forms of asphaltenes in crude oils: molecules, nanoaggregates and clusters. This asphaltene nanoscience approach enables development of the first predictive equation of state for asphaltene compositional gradients in reservoirs, the Flory-Huggins-Zuo (FHZ) EoS. This new asphaltene EoS is readily exploited with "downhole fluid analysis" (DFA) on wireline formation testers thereby elucidating important fluid and reservoir complexities. Field studies confirm the applicability of this scientific formalism and DFA technology for evaluating reservoir compartmentalization and especially connectivity issues providing orders of magnitude improvement over tradional static pressure surveys. Moreover, the mechanism of tar mat formation, a long standing puzzle, is largely resolved by our new asphaltene nanoscience model as shown in field studies. In addition, oil columns possessing large disequilibrium gradients of asphaltenes are shown to be amenable to the new FHZ EoS in a straightforward manner. We also examine recent developments in asphaltene science. For example, important interfacial properties of asphaltenes have been resolved recently providing a simple framework to address surface science. At long last, the solid asphaltenes (as with hydrocarbon gases and liquids) are treated with a proper chemical construct and theoretical formalism. New asphaltene science coupled with new DFA technology will yield increasingly powerful benefits in the future. Copyright 2011, Society of Petroleum Engineers.

Larter S.,Gushor Inc. | Larter S.,University of Calgary | Huang H.,University of Calgary | Adams J.,University of Calgary | And 4 more authors.
Organic Geochemistry | Year: 2012

Existing scales widely used to describe the extent of biodegradation of petroleum have insufficient resolution to usefully characterize many heavy oil and bitumen occurrences, including the volumetrically dominant heavily and severely biodegraded oil accumulations in the foreland basins of western Canada and Venezuela. In these and other deposits, existing classifications or descriptions of the biodegradation level may vary only slightly, yet oil may vary in viscosity by orders of magnitude. The " Manco" biodegradation scale proposed here is based on integrating the extent of degradation of various members of compound classes not included in previous biodegradation scales. They include alkyl aromatic and alkyl thiophenic compounds that show variable extent of alteration in samples degraded to uniform levels on standard scales, but which may show variation in local degradation systematics related to biodegradation mechanisms and extent of oil mixing. The Manco scale uses a combination of a consideration of the extent of alteration within a compound class together with a consideration of biodegradation across a range of compound classes. It can be reliably used as a basis for interpreting geochemical changes in heavily biodegraded oil suites and can also be used to differentiate biodegraded oil samples likely to be amenable to cold production from those requiring production strategies such as steam or chemical flooding. As with other biodegradation scales, the scale may also provide evidence for the influx of later, higher quality oil into a reservoir fluid that had been previously biodegraded. © 2012 Elsevier Ltd.

Fustic M.,University of Calgary | Fustic M.,Nexen Inc. | Fustic M.,Statoil | Bennett B.,Gushor Inc. | And 2 more authors.
Marine and Petroleum Geology | Year: 2012

The Lower Cretaceous McMurray Formation is the primary host of the Athabasca oil sands deposit, one of the largest petroleum deposits in the world. Regional studies show that within the McMurray Formation, bitumen-saturated reservoir sands are encountered within the western, central and northeastern sections of the northeastern Athabasca deposit, while the southeastern part of the deposit has never been charged by petroleum, and that, the lateral contact between petroleum- and water-saturated reservoir sands is in some instances characterized by rapid changes in bitumen saturation, even between closely spaced wells. In the literature, a number of petroleum entrapment schemes have been proposed to explain how the bitumen accumulated through different trapping mechanisms, however controversy remains. This paper investigates the concept of inter-compartmental petroleum "fill and spill" charge and entrapment in a setting where compartments are clearly defined by mud-filled channel deposits. Classical molecular maturity parameters based on gas chromatography - mass spectrometric analysis of hydrocarbon compounds that are extracted from the bitumen show notable changes in composition between the geologically defined reservoir compartments. Relatively higher maturity sourced oil resides in the western compartment while maturity decreases to the eastern most compartment suggesting that the eastern compartment was filled by petroleum of lower maturity which has been displaced via fill and spill as petroleum migration from an increasing maturity source enters compartments to the west. Oil saturation and hydrocarbon geochemistry results also suggest the oil charge was very limited locally and individual compartments located towards the eastern edge of the Athabasca may not have seen the multiple charges evident in the oil sands to the west. The concept of inter-compartmental fill-and-spill provides new insights regarding the often overlooked intra-formational geological controls on reservoir charge in the McMurray Formation. The concept explains that apparently sharp lateral oil-water contacts are in fact due to mud-filled channel deposits which at least locally serve as lateral seals. This concept should be applicable to other meandering fluvial belt reservoirs worldwide and suggests a necessity to revise existing stratigraphic trap schemes by including the point bar stratigraphic play type of trap as one of the trapping mechanisms. Additionally, geochemical gradients can be used as a tool for defining the presence and extent of individual compartments as well as the level of fluid communication as an aid to well placements. © 2012 Elsevier Ltd.

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