This paper reviews the occurrence of biomacromolecules in fossil plants and animals. The range of... more This paper reviews the occurrence of biomacromolecules in fossil plants and animals. The range of techniques used in their release, preparation, microscopy and chemical analysis is described, as is the role of decay experiments in their investigation. The major plant parts that include resistant macromolecules are discussed: algal cell walls, cuticles, spore and pollen walls, propagules, periderm, secondary xylem, and secretions. The chemistry of animal cuticles preserved in the fossil record is briefly considered; they may incorporate macromolecules of plant origin during diagenesis. Some future directions for research are outlined; characterization of sporopollenin, characterization of extant and extinct tissues and organs, chemosystematic investigations, taphonomic processes, investigation of biomacromolecules in animal fossils.
The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-k... more The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-known fields in the UK Continental Shelf (UKCS). At the time of the initial development, Shearwater represented one of the most complex and technically challenging high-pressure and high-temperature (HPHT) developments of its kind in the North Sea. During the early life of the field, pressure depletion resulted in compaction of the Fulmar reservoir, leading to mechanical failure of the development wells. The compaction also resulted in weakening of the overburden due to an effect known as stress arching. Over time, this resulted in in situ stress changes in the overburden which have been observed from 4D seismic datasets and are in line with geomechanical modelling. This is particularly true for the Hod Formation in the Chalk Group, and resulted in the need to make changes to infill well design, including the use of new drilling technologies, to ensure safe and effective well delivery. The insights presented here, which relate to the understanding of pore pressure and fluid fill in the overburden, and how the overburden has responded to stress changes over time, are of relevance to current and future HPHT field developments in both the UK North Sea and elsewhere.
The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-k... more The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-known fields in the UK Continental Shelf (UKCS). At the time of the initial development, Shearwater represented one of the most complex and technically challenging high-pressure and high-temperature (HPHT) developments of its kind in the North Sea. During the early life of the field, pressure depletion resulted in compaction of the Fulmar reservoir, leading to mechanical failure of the development wells. The compaction also resulted in weakening of the overburden due to an effect known as stress arching. Over time, this resulted in in situ stress changes in the overburden which have been observed from 4D seismic datasets and are in line with geomechanical modelling. This is particularly true for the Hod Formation in the Chalk Group, and resulted in the need to make changes to infill well design, including the use of new drilling technologies, to ensure safe and effective well delivery. The insights presented here, which relate to the understanding of pore pressure and fluid fill in the overburden, and how the overburden has responded to stress changes over time, are of relevance to current and future HPHT field developments in both the UK North Sea and elsewhere.
... 3a). In addition, (alkyl)naphthalenes and homologous series of w-alkanes and «-alk-l-enes are... more ... 3a). In addition, (alkyl)naphthalenes and homologous series of w-alkanes and «-alk-l-enes are prominently present. ... Both samples are from Carboniferous Medullosan Pteridosperms. Key: x= «-alk-1-enes, · = w-alkanes, * = contaminants, Ci8 = octadecane, i-Ci9 = Pristane. ...
Fossil leaves which show excellent preservation of lipids and other organic compounds are preserv... more Fossil leaves which show excellent preservation of lipids and other organic compounds are preserved in abundance at the Miocene Clarkia lake deposit in northwestern Idaho, USA. Eighty three fossils from nine genera which are commonly found at the site, namely Quercus, Platanus, Magnolia, Pseudofagus, Fagus, Cocculus, Taxodium, Metasequoia and Sequoia were investigated to assess whether their chemical compositions can be used in chemotaxonomic comparisons. Chromatographically separated n-alkane and n-alkanol sub-fractions were examined by GC and GC/MS to establish whether characteristic distributions were evident between fossils and distinct from the enclosing sediment. Chemotaxonomic comparisons were performed between the individual fossil specimens and six sediments using the nalkane and n-alkanol pro®les and principal component analysis (PCA). Characteristic distributions were observed for certain genera, e.g. Platanus and Quercus, which were reproducible between multiple specimens of the same genus. Concentrations of the lipids in fossils were markedly greater than in the six sediments in all of the fossils except the conifers examined. These ®ndings demonstrate that n-alkyl lipid distributions from fossil leaves have chemotaxonomic utility, with potential for comparisons with modern taxa.
Summary This work demonstrates novel insights into Neoproterozoic-Cambrian petroleum systems and ... more Summary This work demonstrates novel insights into Neoproterozoic-Cambrian petroleum systems and highlights the application of aromatic molecular proxies, which can record information that may be overlooked if only utilizing conventional hopane and sterane biomarkers.
Carotenoids were analysed in ca. 1-cm thick subsamples of three laterally time-equivalent saprope... more Carotenoids were analysed in ca. 1-cm thick subsamples of three laterally time-equivalent sapropels from a west-east transect of the eastern Mediterranean Basin to study euxinic periods during Pliocene sapropel formation. The amount of intact isorenieratene (summed all-trans and cis isomers), ranged from non-detectable at the base and top of a sapropel up to 140 µg/g sediment in the central parts. Isorenieratene accumulation rates at the central and western site are remarkably similar and increase sharply to levels of up to 3.0 mg/m**2/ yr in the central part of the sapropel and then drop to low levels. This pattern indicates an expansion of euxinic conditions reaching into the photic zone, followed by deepening of the chemocline during deposition of this Pliocene sapropel. The sapropel from the easternmost site of the basin, which contains less organic carbon, shows much lower isorenieratene accumulation rates and even absence of isorenieratene in the central part of the sapropel. Ba/Al ratios indicate enhanced palaeoproductivity during sapropel formation, supporting previously proposed models, according to which increased productivity is the driving force for the generation of euxinic conditions.
30th International Meeting on Organic Geochemistry (IMOG 2021), 2021
Summary Diamondoid analysis has become a well-established technique for investigating hydrocarbon... more Summary Diamondoid analysis has become a well-established technique for investigating hydrocarbon fluids over a large maturity range, owing to the great thermal stability of diamondoids and their progressive enrichment with increasing maturity levels. This study presents the first detailed compilation of diamondoids results for hydrocarbon fluids from the North Sea. The data clearly reveals how diamondoid distributions can be used to disentangle maturity and source effects both on a regional as well as a field scale, which provides valuable insights for ongoing exploration efforts as well as further development optimization.
The Pierce Field lies 250 km east of Aberdeen, in the UK sector of the East Central Graben. The f... more The Pierce Field lies 250 km east of Aberdeen, in the UK sector of the East Central Graben. The field comprises twin salt diapirs, forming the trap for oil and free gas in the Paleocene–Eocene Forties Sandstone Member reservoir. The diapirs exerted a strong influence over the sedimentation of the reservoir, with the construction of multistorey sandstone bodies forming a complex reservoir geometry further complicated by a hydrodynamic aquifer.The field currently produces to the Haewene Brim floating production storage and offloading (FPSO) installation, and has undergone several phases of development as the understanding has matured. It was initially developed with six subsea horizontal oil producers tied back to the FPSO, with produced gas reinjected through two gas injectors. In 2004–05, water injection was introduced to South Pierce to provide increased pressure support and improve sweep. To maximize recovery, four additional oil producers were drilled between 2010 and 2016, with ...
29th International Meeting on Organic Geochemistry, 2019
The high-pressure and high temperature (HPHT) Shearwater Field is located in UKCS Block 22/30b. T... more The high-pressure and high temperature (HPHT) Shearwater Field is located in UKCS Block 22/30b. The field comprises gas-condensate at current conditions >10,000 psia reservoir pressure and temperature >300 F in three Jurassic reservoirs, Pentland, Fulmar and Heather. The initial reservoir pressures were in excess of 15,000 psia and reservoir temperatures exceeded 375 F (Jones et al. 2018 and refs therein). The field is located in the East Central Graben close to the Elgin-Franklin fields to the SW and the Erskine Field to the NE. The Field was discovered in 1988 and started first production in 2000.
The Paleontological Society Special Publications, 1992
The Bembridge Limestone Formation (BLF), Late Eocene of Headon Hill, Isle of Wight, England, cont... more The Bembridge Limestone Formation (BLF), Late Eocene of Headon Hill, Isle of Wight, England, contains a diverse array of mammals (around 50 spp.) distributed through 10 levels. Its lower part (“lower fauna”) marks the appearance of a significant number of species, genera and one family unknown from earlier English Late Eocene strata. Towards the top of the BLF there is a reversion to faunas (“upper fauna”) more typical of the underlying Headon Hill Formation. This represents their last appearance in England. The succeeding Bembridge Marls Member fauna is similar to that in the lower part of the BLF. These changes are provincial in scale and may be climate induced (reflecting a slight warming followed by terminal Eocene cooling). Superimposed on these changes are smaller-scale more frequent fluctuations linked to alternating marl and black mud lithologies which may represent local habitat changes. In order to obtain overall understanding of the environment of deposition and taphonomi...
Mesozoic petroleum systems in the West Siberian Basin have been studied extensively and are relat... more Mesozoic petroleum systems in the West Siberian Basin have been studied extensively and are relatively well understood. The two main source systems are the Upper Jurassic marine Bazhenov suite (J3) and the Lower-Middle Jurassic, more terrigenously influenced Togur/Tyumen suites (J1–J2). Most of the oils known to be generated from these sources are produced from Mesozoic reservoirs. However, there is also
This paper reviews the occurrence of biomacromolecules in fossil plants and animals. The range of... more This paper reviews the occurrence of biomacromolecules in fossil plants and animals. The range of techniques used in their release, preparation, microscopy and chemical analysis is described, as is the role of decay experiments in their investigation. The major plant parts that include resistant macromolecules are discussed: algal cell walls, cuticles, spore and pollen walls, propagules, periderm, secondary xylem, and secretions. The chemistry of animal cuticles preserved in the fossil record is briefly considered; they may incorporate macromolecules of plant origin during diagenesis. Some future directions for research are outlined; characterization of sporopollenin, characterization of extant and extinct tissues and organs, chemosystematic investigations, taphonomic processes, investigation of biomacromolecules in animal fossils.
The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-k... more The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-known fields in the UK Continental Shelf (UKCS). At the time of the initial development, Shearwater represented one of the most complex and technically challenging high-pressure and high-temperature (HPHT) developments of its kind in the North Sea. During the early life of the field, pressure depletion resulted in compaction of the Fulmar reservoir, leading to mechanical failure of the development wells. The compaction also resulted in weakening of the overburden due to an effect known as stress arching. Over time, this resulted in in situ stress changes in the overburden which have been observed from 4D seismic datasets and are in line with geomechanical modelling. This is particularly true for the Hod Formation in the Chalk Group, and resulted in the need to make changes to infill well design, including the use of new drilling technologies, to ensure safe and effective well delivery. The insights presented here, which relate to the understanding of pore pressure and fluid fill in the overburden, and how the overburden has responded to stress changes over time, are of relevance to current and future HPHT field developments in both the UK North Sea and elsewhere.
The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-k... more The Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-known fields in the UK Continental Shelf (UKCS). At the time of the initial development, Shearwater represented one of the most complex and technically challenging high-pressure and high-temperature (HPHT) developments of its kind in the North Sea. During the early life of the field, pressure depletion resulted in compaction of the Fulmar reservoir, leading to mechanical failure of the development wells. The compaction also resulted in weakening of the overburden due to an effect known as stress arching. Over time, this resulted in in situ stress changes in the overburden which have been observed from 4D seismic datasets and are in line with geomechanical modelling. This is particularly true for the Hod Formation in the Chalk Group, and resulted in the need to make changes to infill well design, including the use of new drilling technologies, to ensure safe and effective well delivery. The insights presented here, which relate to the understanding of pore pressure and fluid fill in the overburden, and how the overburden has responded to stress changes over time, are of relevance to current and future HPHT field developments in both the UK North Sea and elsewhere.
... 3a). In addition, (alkyl)naphthalenes and homologous series of w-alkanes and «-alk-l-enes are... more ... 3a). In addition, (alkyl)naphthalenes and homologous series of w-alkanes and «-alk-l-enes are prominently present. ... Both samples are from Carboniferous Medullosan Pteridosperms. Key: x= «-alk-1-enes, · = w-alkanes, * = contaminants, Ci8 = octadecane, i-Ci9 = Pristane. ...
Fossil leaves which show excellent preservation of lipids and other organic compounds are preserv... more Fossil leaves which show excellent preservation of lipids and other organic compounds are preserved in abundance at the Miocene Clarkia lake deposit in northwestern Idaho, USA. Eighty three fossils from nine genera which are commonly found at the site, namely Quercus, Platanus, Magnolia, Pseudofagus, Fagus, Cocculus, Taxodium, Metasequoia and Sequoia were investigated to assess whether their chemical compositions can be used in chemotaxonomic comparisons. Chromatographically separated n-alkane and n-alkanol sub-fractions were examined by GC and GC/MS to establish whether characteristic distributions were evident between fossils and distinct from the enclosing sediment. Chemotaxonomic comparisons were performed between the individual fossil specimens and six sediments using the nalkane and n-alkanol pro®les and principal component analysis (PCA). Characteristic distributions were observed for certain genera, e.g. Platanus and Quercus, which were reproducible between multiple specimens of the same genus. Concentrations of the lipids in fossils were markedly greater than in the six sediments in all of the fossils except the conifers examined. These ®ndings demonstrate that n-alkyl lipid distributions from fossil leaves have chemotaxonomic utility, with potential for comparisons with modern taxa.
Summary This work demonstrates novel insights into Neoproterozoic-Cambrian petroleum systems and ... more Summary This work demonstrates novel insights into Neoproterozoic-Cambrian petroleum systems and highlights the application of aromatic molecular proxies, which can record information that may be overlooked if only utilizing conventional hopane and sterane biomarkers.
Carotenoids were analysed in ca. 1-cm thick subsamples of three laterally time-equivalent saprope... more Carotenoids were analysed in ca. 1-cm thick subsamples of three laterally time-equivalent sapropels from a west-east transect of the eastern Mediterranean Basin to study euxinic periods during Pliocene sapropel formation. The amount of intact isorenieratene (summed all-trans and cis isomers), ranged from non-detectable at the base and top of a sapropel up to 140 µg/g sediment in the central parts. Isorenieratene accumulation rates at the central and western site are remarkably similar and increase sharply to levels of up to 3.0 mg/m**2/ yr in the central part of the sapropel and then drop to low levels. This pattern indicates an expansion of euxinic conditions reaching into the photic zone, followed by deepening of the chemocline during deposition of this Pliocene sapropel. The sapropel from the easternmost site of the basin, which contains less organic carbon, shows much lower isorenieratene accumulation rates and even absence of isorenieratene in the central part of the sapropel. Ba/Al ratios indicate enhanced palaeoproductivity during sapropel formation, supporting previously proposed models, according to which increased productivity is the driving force for the generation of euxinic conditions.
30th International Meeting on Organic Geochemistry (IMOG 2021), 2021
Summary Diamondoid analysis has become a well-established technique for investigating hydrocarbon... more Summary Diamondoid analysis has become a well-established technique for investigating hydrocarbon fluids over a large maturity range, owing to the great thermal stability of diamondoids and their progressive enrichment with increasing maturity levels. This study presents the first detailed compilation of diamondoids results for hydrocarbon fluids from the North Sea. The data clearly reveals how diamondoid distributions can be used to disentangle maturity and source effects both on a regional as well as a field scale, which provides valuable insights for ongoing exploration efforts as well as further development optimization.
The Pierce Field lies 250 km east of Aberdeen, in the UK sector of the East Central Graben. The f... more The Pierce Field lies 250 km east of Aberdeen, in the UK sector of the East Central Graben. The field comprises twin salt diapirs, forming the trap for oil and free gas in the Paleocene–Eocene Forties Sandstone Member reservoir. The diapirs exerted a strong influence over the sedimentation of the reservoir, with the construction of multistorey sandstone bodies forming a complex reservoir geometry further complicated by a hydrodynamic aquifer.The field currently produces to the Haewene Brim floating production storage and offloading (FPSO) installation, and has undergone several phases of development as the understanding has matured. It was initially developed with six subsea horizontal oil producers tied back to the FPSO, with produced gas reinjected through two gas injectors. In 2004–05, water injection was introduced to South Pierce to provide increased pressure support and improve sweep. To maximize recovery, four additional oil producers were drilled between 2010 and 2016, with ...
29th International Meeting on Organic Geochemistry, 2019
The high-pressure and high temperature (HPHT) Shearwater Field is located in UKCS Block 22/30b. T... more The high-pressure and high temperature (HPHT) Shearwater Field is located in UKCS Block 22/30b. The field comprises gas-condensate at current conditions >10,000 psia reservoir pressure and temperature >300 F in three Jurassic reservoirs, Pentland, Fulmar and Heather. The initial reservoir pressures were in excess of 15,000 psia and reservoir temperatures exceeded 375 F (Jones et al. 2018 and refs therein). The field is located in the East Central Graben close to the Elgin-Franklin fields to the SW and the Erskine Field to the NE. The Field was discovered in 1988 and started first production in 2000.
The Paleontological Society Special Publications, 1992
The Bembridge Limestone Formation (BLF), Late Eocene of Headon Hill, Isle of Wight, England, cont... more The Bembridge Limestone Formation (BLF), Late Eocene of Headon Hill, Isle of Wight, England, contains a diverse array of mammals (around 50 spp.) distributed through 10 levels. Its lower part (“lower fauna”) marks the appearance of a significant number of species, genera and one family unknown from earlier English Late Eocene strata. Towards the top of the BLF there is a reversion to faunas (“upper fauna”) more typical of the underlying Headon Hill Formation. This represents their last appearance in England. The succeeding Bembridge Marls Member fauna is similar to that in the lower part of the BLF. These changes are provincial in scale and may be climate induced (reflecting a slight warming followed by terminal Eocene cooling). Superimposed on these changes are smaller-scale more frequent fluctuations linked to alternating marl and black mud lithologies which may represent local habitat changes. In order to obtain overall understanding of the environment of deposition and taphonomi...
Mesozoic petroleum systems in the West Siberian Basin have been studied extensively and are relat... more Mesozoic petroleum systems in the West Siberian Basin have been studied extensively and are relatively well understood. The two main source systems are the Upper Jurassic marine Bazhenov suite (J3) and the Lower-Middle Jurassic, more terrigenously influenced Togur/Tyumen suites (J1–J2). Most of the oils known to be generated from these sources are produced from Mesozoic reservoirs. However, there is also
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