Petroleum Geoscience最新文献

{"title":"Structural characterization and across-fault seal assessment of the Aurora CO\u0000 2\u0000 storage site, northern North Sea","authors":"Nora Holden, J. Osmond, M. Mulrooney, A. Braathen, E. Skurtveit, Anja Sundal","doi":"10.1144/petgeo2022-036","DOIUrl":"https://doi.org/10.1144/petgeo2022-036","url":null,"abstract":"\u0000 Faults play an essential role at many potential CO\u0000 2\u0000 storage sites because they can act as conduits or barriers to fluid flow. To contribute to the evaluation of the Aurora storage site in the northern North Sea, we perform a structural characterization and assessment of across-fault seals that displace the Lower Jurassic storage complex. We find that first-order faults are predominately N–S-striking, and W-dipping, with throws greater than the thickness of the primary seal (>85 m). In contrast, second-order faults have lower throws (15–50 m) and variable strike and dip directions. Due to the dip of the storage complex, injected CO\u0000 2\u0000 is likely to migrate northwards before encountering the first-order Svartalv Fault Zone on its footwall side, which juxtaposes the storage units against younger sand-rich units. However, shale gouge ratio values exceed 0.30 at the depth of the storage complex, suggesting that a fault membrane seal may be present. Furthermore, second-order NE-dipping faults create juxtaposition seals and, in places, small-scale structural traps (24–48 m) along the Svartalv Fault Zone. Overall, we suggest that faults within the Aurora storage site could provide barriers to plume migration allowing more CO\u0000 2\u0000 to become trapped, thereby increasing the storage capacity.\u0000 \u0000 \u0000 This article is part of the Energy Geoscience Series available at\u0000 https://www.lyellcollection.org/cc/energy-geoscience-series\u0000","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44840668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fracture Pressure, Leak-Off Tests and Poisson's Ratio","authors":"R. Lahann, R. Swarbrick","doi":"10.1144/petgeo2021-103","DOIUrl":"https://doi.org/10.1144/petgeo2021-103","url":null,"abstract":"Fracture pressure models are used to create pre-drill fracture pressure/depth plots essential to the design of drilling and casing programs in oil and gas wells, and future development of carbon capture and underground storage. Some of these models include an empirical term (stress ratio) which relates effective horizontal stress to effective vertical stress. Based on the literature, stress ratio is assumed to vary with compaction and can be calculated from Poisson's ratio (ν). An alternative to models which utilize the stress ratio term is a model which relates fracture pressure to a constant fraction of the vertical stress. This paper demonstrates that a constant fraction of vertical stress is equivalent to a stress ratio which increases slightly with depth.Estimation of how the ν changes with compaction is complicated by the multiple methods which are commonly employed to measure ν. The available static and dynamic ν data suggest a substantial decrease in ν with porosity reduction. Evaluation of in situ ν data from leak-off tests (LOTS) and associated fluid pressure data in Tertiary Basins indicates that in situ ν does not decline as rapidly as indicated by the other methods of ν determination. In situ ν data indicate that calibration of stress ratio from traditional ν methods is not appropriate and may substantially underestimate fracture pressure (Fp).Fracture pressure models which utilize a constant fraction of vertical stress or estimate stress ratio empirically from LOT data should be employed for pre-drill estimation of fracture pressure.Thematic collection: This article is part of the Geopressure collection available at: https://www.lyellcollection.org/cc/geopressure","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41392704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Insights into the Structure, Geology and Hydrocarbon Prospectivity along the Central-Northern Corona Ridge, Faroe-Shetland Basin","authors":"Lucinda K. Layfield, N. Schofield, D. Jolley, S. Holford, Tudor-Remus Volintir, Ben A. Kilhams, D. Muirhead, Helen Cromie","doi":"10.1144/petgeo2021-090","DOIUrl":"https://doi.org/10.1144/petgeo2021-090","url":null,"abstract":"The Faroe-Shetland Basin (FSB) is one of the only significant exploration frontiers remaining on the UK Continental Shelf. Over half of the basin's discovered reserves and resources lie along two intra-basinal highs, the Corona Ridge and Rona Ridge. In contrast to the Rona Ridge, the central-northern Corona Ridge has received much less attention. To reveal new insights into the geology, structural configuration, and hydrocarbon prospectivity of the central-northern Corona Ridge we analyse 3D seismic data and data from exploration wells 213/23-1 (Eriboll), 214/21a-2 (South Uist) and 213/25c-1V (North Uist). This study extends the Colsay T40-T45 sub- and intra-basaltic play concept from the Rosebank Field NE along the Corona Ridge, at least into 213/23-1. Analysis also suggests that no Triassic strata are present within 213/23-1, challenging the previous understanding of Triassic distribution within the central FSB. Our findings show that the central-northern Corona Ridge is structurally complex, comprised of a series of discrete basement bounding faults, down-flank fault terraces and faults which are oblique to the dominant NE-SW-striking structural fabrics of the FSB.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42908497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of shale depth functions in contrasting offshore basins and sealing behaviour for CH4 and CO2 containment systems","authors":"O. Nhabanga, P. Ringrose","doi":"10.1144/petgeo2021-101","DOIUrl":"https://doi.org/10.1144/petgeo2021-101","url":null,"abstract":"Mudrock compaction trends from the Rovuma basin offshore Mozambique are compared with those of the Norwegian North Sea, the Gulf of Mexico and the Kutai basin offshore Indonesia. The comparison reveals that burial rates and timing of rifting are the dominant causes for the differences observed. The compaction trend for the Rovuma basin is broadly similar to the trends for the Kutai basin and the Gulf of Mexico, but very different from those for the Norwegian North Sea data, which show higher porosity and shallower onset of overpressure than those from the other three basins. The relationships for seismic velocities as a function of depth show strong similarities between the Rovuma and Gulf of Mexico basins.We then use these comparisons to make a general assessment of the capillary sealing potential of Cretaceous mudrocks in the Rovuma basin, using a mudstone permeability prediction function and a method for mapping permeability to threshold pressure, allowing estimation of maximum column heights for CO2 and CH4, with uncertainty ranges. Predicted CO2 column heights are slightly less than the equivalent CH4 column heights. The observed CH4 column height at one of the wells is significantly lower than that predicted from mudstone permeability, which is probably due to other factors such as fracturing or gas migration out of the structure. The comparison indicates generally good capillary sealing potential for the Rovuma basin Cretaceous shales and offers a general approach for assessing CO2 storage potential from hydrocarbon sealing datasets from multiple offshore basins.This article is part of the Energy Geoscience Series available at https://www.lyellcollection.org/cc/energy-geoscience-series","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49313373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress state in parts of North-East India: borehole collapse modelling with sensitivity analysis","authors":"J. Alam, R. Chatterjee, S. Dasgupta, B. Das","doi":"10.1144/petgeo2021-059","DOIUrl":"https://doi.org/10.1144/petgeo2021-059","url":null,"abstract":"Structural heterogeneities and tectonic forces in North-East India give rise to changeable in-situ stresses with varying orientations in this part of India. Wells located in the seismic gap in Upper Assam, Naga Thrust and Chittagong-Mizoram-Tripura fold belt of Mizoram are considered for studying the stress state and borehole collapse models for the area. The absence of stress studies in the Mizoram area acts as a stimulator to take up stress studies. Poroelastic modeling shows an average ratio of maximum horizontal to vertical stress to be 0.79 for normal faulted, 1.18 for thrust faulted and 1.12 in strike-slip faulted regimes. The SH direction varies from 193°N in Upper Assam to 213°N in Mizoram areas. The image log in a well of the Mizoram area shows the rotation of SH direction (≈85°) from 500m to 3707m due to structural heterogeneity. The thrust and strike-slip regimes under the study area pose the major threat for safe borehole drilling in this complex terrain. To mitigate this issue, Mohr-Coulomb (MC) and Mogi-Coulomb (MG) rock failure criteria are discussed to predict minimum mud weight for borehole drilling. MG predicted mud weight (MW) ensures borehole stability in wells in normal faulted sediments while MC predicted MW prevents shear failure in wells in thrust and strike-slip regimes. A disc plot is used to model a stable wellbore drilling path with minimum MW is modeled using a disc plot. A vertical well is stable in a normal faulted regime whereas horizontal drilling is preferable in the fold-thrust belt. Sensitivity analysis of geomechanical input parameters on MW using Monte Carlo Simulation shows that SH has the maximum effect on MW regardless of the faulting regimes.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47664366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrographic and diagenetic investigation of the distal Triassic 'Budleighensis fluvial system in the Solway and Carlisle Basins for potential CO2 storage","authors":"J. R. Marsh, S. J. Jones, N. S. Meadows, J. G. Gluyas","doi":"10.1144/petgeo2021-065","DOIUrl":"https://doi.org/10.1144/petgeo2021-065","url":null,"abstract":"<p>Failure to find hydrocarbon prospects in the Solway Basin region has resulted in a lack of research into the local Sherwood Sandstone Group petrography, reservoir quality and depositional history compared to the analogous southern reservoirs in the EISB which will be utilized for carbon storage. A detailed petrographic study is presented which aims to understand if the Solway Firth could have similar utility. The Permo&ndash;Triassic Sherwood Sandstone Group is believed to be deposited in depocentres connected during the Early Triassic by the extensive &lsquo;Budleighensis&rsquo; fluvial system. Here, the Solway and Carlisle basins are proposed as terminal sites for this endorheic system, with the Lower Triassic Annan Sandstone Formation ascribed to the distal region of a fluvial distributary zone and the overlying Kirklinton Sandstone Formation thought to mark a transition to a basinal zone, depositing aeolian sandstones and locally associated playa lake facies. Fluid inclusion, stable isotope burial history modelling and field observations have been used to assess the relative timing and importance of different diagenetic cements. Early diagenetic cements include grain-rimming haematite and patchy calcite cement, especially in the Annan Sandstone Formation. Later burial diagenesis sees further calcite cement, quartz overgrowths and, restricted to the Kirklinton Sandstone Formation, ferroan dolomite. Porosity and permeability show significant differences between fluvial Annan and aeolian Kirklinton facies associations. Despite the finer grain size, a reservoir with excellent porosity and permeability as well as no hydrocarbon charging or legacy hydrocarbon extraction is persevered, suggesting the Solway Basin could be a secure CO<SUB>2</SUB> storage site.</p>\u0000<p>This article is part of the Energy Geoscience Series available at https://www.lyellcollection.org/cc/energy-geoscience-series</p>\u0000<p><b>Supplementary material:</b> An overview of the primary and secondary data collected and utilised in this study, as well as raw data values are available at https://doi.org/10.6084/m9.figshare.c.5906677</p>","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"75 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138542451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation and estimation of overpressure from wireline logs using deterministic approaches in western Indonesia's Tertiary sedimentary basins","authors":"Agus M. Ramdhan, Stephen O'Connor","doi":"10.1144/petgeo2021-062","DOIUrl":"https://doi.org/10.1144/petgeo2021-062","url":null,"abstract":"<p>Many basins in Indonesia such as the North Sumatra, South Sumatra and Lower Kutai are highly overpressured. As a result, some wells have experienced drilling problems resulting in termination. In the literature, an empirical relationship such as Eaton has historically often been used to interpret pore pressure. In this paper, we take an alternative approach, one based on deterministic models.</p>\u0000<p>Herein, we use Bowers&rsquo; and Dutta's equations to calculate the contributions of loading and unloading to the overall overpressure. Due to the advantages of the density log, the contributions of loading and unloading can be discriminated. By applying these methods, we suggest that in the North Sumatra Basin, unloading is caused by clay diagenesis. In the others, gas generation is significant.</p>\u0000<p>The analysis also reveals that the unloading parameter (<I>U</I>) in the North Sumatra and South Sumatra basins is different than that of <I>U</I> in the Lower Kutai Basin. This suggests that mudrock in the overpressure zone in the Sumatran basins is more elastic than that in the Lower Kutai Basin, which appears to be more plastic in behaviour.</p>\u0000<p><b>Thematic collection:</b> This article is part of the Geopressure collection available at: https://www.lyellcollection.org/cc/geopressure</p>","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"98 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138520204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Role of Creep in Geopressure Development","authors":"K. You, P. Flemings, Athma R. Bhandari, M. Heidari, J. Germaine","doi":"10.1144/petgeo2021-064","DOIUrl":"https://doi.org/10.1144/petgeo2021-064","url":null,"abstract":"This study developed a one-dimensional numerical model of sedimentation and compaction based on the equivalent isochrone framework to investigate the impact of creep on geopressure during burial. In this framework, the void ratio is a function of effective stress and strain rate; the change in void ratio is the same with each order of magnitude decrease in strain rate at a constant effective stress. We simulated lower void ratio and higher overpressure when creep was included compared to cases where no creep was present and void ratio is only a function of effective stress. Creep causes apparent overconsolidation. The apparent overconsolidation ratio is used to quantify the magnitude of creep; this is the vertical distance from the normal compression curve in a void ratio versus effective stress plot. The magnitude of creep depends on the loading rate, and increases with depth at sites with low sedimentation rates. These findings bridge the gap between laboratory and field observations on rock compression behaviors. For example, it provides one explanation why laboratory-derived compression curves have a higher void ratio at a given effective stress. In addition, it suggests under what conditions the rock will behave elastically.Thematic collection: This article is part of the Geopressure collection available at: https://www.lyellcollection.org/cc/geopressure","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44822793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clumped isotope constraints on the origins of reservoir methane from the Barents Sea","authors":"N. Thiagarajan, J. H. Pedersen, H. Brunstad, J. Rinna, A. Lepland, J. Eiler","doi":"10.1144/petgeo2021-037","DOIUrl":"https://doi.org/10.1144/petgeo2021-037","url":null,"abstract":"The Barents Sea basin is an oil and gas province containing more than 760 million tons of oil equivalents. The reservoir geology of the Barents Sea is complex due to multiple episodes of subsidence, uplift and erosion, which opened a network of extensional and wrench related faults allowing for fluid migration. The multifaceted geological history complicates efforts to describe the source and characteristics of natural gas in the subsurface Barents Sea. Here we apply stable isotopes, including methane clumped isotope measurements, to thirteen natural gases from five (Skrugard Appraisal, Havis, Alta, Filicudi, and Svanefjell) reservoirs in the Loppa High area in the southwestern Barents Sea to estimate the origins of methane. We compare estimates of methane formation temperature based on clumped isotopes to thermal evolution models for the region. We find that the methane has diverse origins including microbial and thermogenic sources forming and equilibrating at temperatures ranging from 34–238°C. Our clumped isotope temperature estimates are consistent with thermal evolution models for the area. These temperatures can be explained by gas generation and expulsion in the oil and gas window followed by isotopic re-equilibration in some reservoirs due to microbial methanogenesis and/or anaerobic oxidation of methane. Gases from the Skrugard Appraisal, Havis and Alta have methane equilibration temperatures consistent with maximum burial temperatures, while gases from Svanefjell have methane equilibration temperatures consistent with current reservoir temperature, suggesting isotope re-equilibration in the shallow reservoir. Gases from Filicudi on the other hand are consistent with generation over multiple points over its thermal history.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45408574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the role of differential biotic production on carbonate geometries through stratigraphic forward modelling and sensitivity analysis: the Llucmajor example","authors":"T. O. Tella, G. Winterleitner, M. Mutti","doi":"10.1144/petgeo2021-053","DOIUrl":"https://doi.org/10.1144/petgeo2021-053","url":null,"abstract":"The geometry of carbonate platforms reflects the interaction of several factors. However, the impact of carbonate-producing organisms has been poorly investigated so far. This study applies stratigraphic forward modelling (SFM) and sensitivity analysis to examine, referenced to the Miocene Llucmajor Platform, the effect of changes of dominant biotic production in the oligophotic and euphotic zones on platform geometry. Our results show that the complex interplay of carbonate production rates, bathymetry and variations in accommodation space control the platform geometry. The main driver of progradation is the oligophotic production of rhodalgal sediments during the lowstands. This study demonstrates that platform geometry and internal architecture varies significantly according to the interaction of the predominant carbonate-producing biotas. The input parameters for this study are based on well-understood Miocene carbonate biotas with characteristic euphotic, oligophotic and photo-independent carbonate production in which it is crucial that each carbonate-producing class is modelled explicitly within the simulation run and not averaged with a single carbonate production–depth profile. This is important in subsurface exploration studies based on stratigraphic forward models where the overall platform geometry may be approximated through calibration runs, and constrained by seismic surveys and wellbores. However, the internal architecture is likely to be oversimplified without an in-depth understanding of the target carbonate system and a transfer to forward modelling parameters.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48017746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}