Evidence for biodegradation and evaporative fractionation in West Sak, Kuparuk and Prudhoe Bay field areas, North Slope, Alaska

Masterson, W. Dallam; Dzou, Leon; Holba, Á.; Fincannon, Ann L; Ellis, Leroy

doi:10.1016/s0146-6380(00)00187-x

Cited by 139 publications

(66 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is consistent with reports from other deep subsurface environments that microbial activity is stimulated at geochemical interfaces (Parkes et al, 2005). When the water leg contains low levels of sulphate, hydrocarbon degradation is driven by methanogenesis; indeed, many biodegraded petroleum reservoirs contain isotopically light methane indicative of a mixed secondary biogenic and thermogenic source (Scott et al, 1994;Larter et al, 1999;Sweeney and Taylor, 1999;Pallasser, 2000;Boreham et al, 2001;Masterson et al, 2001;Head et al, 2003).…”

Section: Introductionsupporting

confidence: 85%

“…Reduced naphthoic acids, metabolites characteristic of anaerobic hydrocarbon degradation have been detected in biodegraded petroleum reservoirs, but not in nondegraded reservoirs (Aitken et al, 2004). Geochemical and isotopic evidence also suggests that in many cases the end product of hydrocarbon degradation in petroleum reservoirs is methane (Scott et al, 1994;Larter et al, 1999;Sweeney and Taylor, 1999;Pallasser, 2000;Boreham et al, 2001;Masterson et al, 2001). Compositional gradients in oil columns towards the underlying water leg in biodegraded petroleum reservoirs suggests that the oil water transition zone is the primary site of biodegradation in petroleum reservoirs Larter et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermodynamic constraints on methanogenic crude oil biodegradation

2007

View full text Add to dashboard Cite

Methanogenic degradation of crude oil hydrocarbons is an important process in subsurface petroleum reservoirs and anoxic environments contaminated with petroleum. There are several possible routes whereby hydrocarbons may be converted to methane: (i) complete oxidation of alkanes to H 2 and CO 2 , linked to methanogenesis from CO 2 reduction; (ii) oxidation of alkanes to acetate and H 2 , linked to acetoclastic methanogenesis and CO 2 reduction; (iii) oxidation of alkanes to acetate and H 2 , linked to syntrophic acetate oxidation and methanogenesis from CO 2 reduction; (iv) oxidation of alkanes to acetate alone, linked to acetoclastic methanogenesis and (v) oxidation of alkanes to acetate alone, linked to syntrophic acetate oxidation and methanogenesis from CO 2 reduction. We have developed the concept of a 'window of opportunity' to evaluate the range of conditions under which each route is thermodynamically feasible. On this basis the largest window of opportunity is presented by the oxidation of alkanes to acetate alone, linked to acetoclastic methanogenesis. This contradicts field-based evidence that indicates that in petroleum rich environments acetoclastic methanogenesis is inhibited and that methanogenic CO 2 reduction is the predominant methanogenic process. Our analysis demonstrates that under those biological constraints oxidation of alkanes to acetate and H 2 , linked to syntrophic acetate oxidation and methanogenesis from CO 2 reduction offers a greater window of opportunity than complete oxidation of alkanes to H 2 and CO 2 linked to methanogenic CO 2 reduction, and hence is the process most likely to occur.

show abstract

Section: Introductionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Thermodynamic constraints on methanogenic crude oil biodegradation

2007

View full text Add to dashboard Cite

show abstract

“…The majority of these faults dip south, consistent with the polarity of Jurassic rifting observed elsewhere on the Alaska North Slope (Hubbard et al, 1987;Bird, 1999). Abutting and cross-cutting relationships indicate that the north-northeast-trending faults postdate many of the west-northwest-trending faults (Figure 3), which is supported by the northnortheast-trending faults consistent with those that cut the Brookian sequence in the Cenozoic , which have been shown to cut the top of the Kuparuk Formation (Masterson et al, 2001).…”

Section: Fault Network Characteristics General Structural Trends and mentioning

confidence: 84%

Fault interactions and reactivation within a normal-fault network at Milne Point, Alaska

Nixon¹,

Sanderson²,

Dee³

et al. 2014

Bulletin

View full text Add to dashboard Cite

A normal-fault network from Milne Point, Alaska, is investigated focusing on characterizing geometry, displacement, strain, and different fault interactions. The network, constrained from threedimensional seismic reflection data, comprises two generations of faults: Cenozoic north-northeast-trending faults and Jurassic west-northwest-trending faults, which highly compartmentalize Upper Triassic to Lower Cretaceous reservoirs. The west-northwest-trending faults are influenced by a similarly oriented underlying structural grain. This influence is characterized by increases in throw on several faults, strain localization, reorientation of faults and an increase in linkage maturity.Reconstructing fault plane geometries and mapping spatial variations in throw identified key characteristic features in their interactions and reactivation of pre-existing structures. Faults are divided into isolated, abutting, and splaying faults. Isolated faults exhibit a range of displacement profiles depending on the degree of restriction at fault tips. Fault splays accommodate step-like decreases in throw along larger main faults with a throw maximum at the intersection with the main fault. Throw profiles of abutting faults are divided into two groups: early stage abutting faults with throw minima at both the isolated and abutting tips, and developed abutting faults with throw maxima near the abutting tip.Developed abutting faults accumulate throw after initial abutment, locally reactivating and transferring throw onto the preexisting fault. Two abutting faults can link kinematically by Stephen Dee is a senior structural geologist at BP, working in the Integrated Subsurface Description and Modelling team and consulting on structural and geomechanics projects. He has a Ph.D. from the University of Southampton and specializes in fault and fracture interpretation, geomechanical modeling, and seal analysis.

show abstract

“…Evaporative fractionation may also occur from loss of solution gas or gas cap (Masterson et al 2001). Variations in the composition of n-alkanes and C 7 components are used to compare oils and determine and possibly quantify the impact of evaporative fractionation on fluid properties, which can also be used to determine the history of the petroleum system (Masterson et al 2001;Losh et al 2002a, b;Thompson 2010;Murillo et al 2016). Experimental separation of liquid and gas phases shows the δ 13 C of C 6 , C 7 and C 8 n-alkanes are identical in both the gas phase and the original oil.…”

Section: Other In-reservoir Processesmentioning

confidence: 99%

Carbon and hydrogen isotopic compositions of n -alkanes as a tool in petroleum exploration

Pedentchouk

Turich

2017

View full text Add to dashboard Cite

Compound-specific isotope analysis (CSIA) of individual organic compounds is a powerful but underutilized tool in petroleum exploration. When integrated with other organic geochemical methodologies it can provide evidence of fluid histories including source, maturity, charge history and reservoir processes that can support field development planning and exploration efforts. The purpose of this chapter is to provide a review of the methodologies used for generating carbon and hydrogen isotope data for mid-and high-molecular-weight n-alkanes.We discuss the factors that control stable carbon and hydrogen isotope compositions of n-alkanes and related compounds in sedimentary and petroleum systems and review current and future applications of this methodology for petroleum exploration. We discuss basin-specific case studies that demonstrate the usefulness of CSIA either when addressing particular aspects of petroleum exploration (e.g. charge evaluation, source rock-oil correlation, and investigation of maturity and in-reservoir processes) or when this technique is used to corroborate interpretations from integrated petroleum systems analysis, providing unique insights which may not be revealed when using other methods. CSIA of n-alkanes and related n-alkyl structures can provide independent data to strengthen petroleum systems concepts from generation and expulsion of fluids from source rock, to charge history, connectivity, and in-reservoir processes.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.Petroleum geoscientists use organic geochemistry as an essential tool in oil and gas exploration and field development planning. Relatively low-cost, high-throughput bulk data are commonly used to screen for source rock quality (e.g. per cent total organic carbon (%TOC), hydrogen and oxygen indices) and thermal maturity (Tmax, vitrinite reflectance equivalent). More in-depth geochemical analytical techniques are used in the context of full fluid and reservoir properties to correlate source rocks and reservoir oils, to determine fluid generation and migration history, including presentday reservoir connectivity, and to understand in-reservoir processes, such as biodegradation of in-reservoir oils. These tools are especially powerful when coupled with other measurements made during the exploration and development process, such as compositional analysis during drilling, downhole fluid analysis and other wireline measurements, and pressure, volume, temperature (PVT) and chemical analyses, integrated in the context of geological static and reservoir dynamic models.Molecular biomarkers have been employed in petroleum exploration for several decades (Peters et al. 2005). The usefulness of bulk stable isotope measurements of gases and oils was well demonstrated in the petroleum industry through the decades of the 1970s and 1980s (Stahl 1977;Schoell 1984;Sofer 1984). However, the use of compound-specific isotopic composition of light hydrocarbons, alkanes and biomarkers is less common....

show abstract

Evidence for biodegradation and evaporative fractionation in West Sak, Kuparuk and Prudhoe Bay field areas, North Slope, Alaska

Cited by 139 publications

References 40 publications

Thermodynamic constraints on methanogenic crude oil biodegradation

Thermodynamic constraints on methanogenic crude oil biodegradation

Fault interactions and reactivation within a normal-fault network at Milne Point, Alaska

Carbon and hydrogen isotopic compositions of n -alkanes as a tool in petroleum exploration

Contact Info

Product

Resources

About