Petroleum Geoscience最新文献

{"title":"The influence of sedimentary facies, mineralogy, and diagenesis on reservoir properties of the coal-bearing Upper Carboniferous of NW Germany","authors":"J. Greve, Benjamin Busch, Dennis Quandt, Mathias Knaak, C. Hilgers","doi":"10.1144/petgeo2023-020","DOIUrl":"https://doi.org/10.1144/petgeo2023-020","url":null,"abstract":"Former coal mines hosted in Upper Carboniferous silt- and sandstones in the Ruhr Basin, NW Germany, are currently examined for post-mining applications (e.g., geothermal energy) and are also important tight-gas reservoir analogs. Core material from well Pelkum-1, comprising Westphalian A (Bashkirian) delta deposits, was studied. The sandstones and siltstones are generally tight (mean porosity 5.5 %; mean permeability 0.26 mD). Poor reservoir properties primarily result from pronounced mechanical compaction (mean COPL 38.8 %) due to deep burial and high contents of ductile rock fragments. Better reservoir properties in sandstones (> 8 %; > 0.01 mD) are due to (1) lower volumes of ductile grains (< 38 %) that deform during mechanical compaction and (2) higher volumes in feldspar and unstable rock fragments. During burial these form secondary porosity (> 1.5 %) resulting from acidic pore water from organic matter maturation. Still, sandstones with enhanced porosities only show a small increase in permeability since authigenic clays (i.e., kaolinite and illite) or late diagenetic carbonates (i.e., siderite and ferroan dolomite/ankerite) clog secondary porosity. Quartz cementation has a minor impact on reservoir properties. Evaluating the Si/Al ratio can be a suitable proxy to assess grain sizes and may be a convenient tool for further exploration.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7003156\u0000","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"47 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444903","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":"Natural fractures at depth in shale reservoirs: new insights from the southern Sichuan Basin marine shales","authors":"Tao Nian, Yuhan Tan, Fengsheng Zhang, Heng Wu, Chengqian Tan, Pengbao Zhang","doi":"10.1144/petgeo2023-071","DOIUrl":"https://doi.org/10.1144/petgeo2023-071","url":null,"abstract":"Natural fractures are pervasive in southern Sichuan Basin marine shales, China, and provide a desired opportunity to understand subsurface fracture network in shale reservoirs. Based on cores and electrical imaging logs from vertical and horizontal petroleum wells in southern Sichuan Basin, four types of natural fractures are identified in terms of orientation, size, filling properties, and spatial distribution. The uncemented bed-parallel shear fracture is developed at or in the vicinity of the mechanical interfaces and inclined to present in shale layers with dip angles greater than 12°. The cemented bed-parallel fracture is characterized with crack-seal texture marked by multiple bands of fibrous cement, and its intensity decreases upwards and shows a positive relation with the TOC values. The uncemented bed-oblique fracture is barely developed, and bears limited open space. The cemented bed-oblique/perpendicular fracture is the most developed fracture type and distributed on a regional scale with a pattern of two systematic sets. The results imply that these shale fractures could be formed sequentially by local and regional tectonic deformation, and by abnormally high-pressure. Most natural fractures cannot contribute to reservoir storage or efficiently enhance its permeability yet can act as planes of weakness and be potentially reactivated during hydraulic fracture treatments.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"50 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139384958","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":"Simultaneous Well Spacing and Completion Optimization Using Automated Machine Learning Approach. A Case Study of Marcellus Shale Reservoir in the North-Eastern United States","authors":"E. Fathi, Ali Takbiri-Borujeni, F. Belyadi, M. F. Adenan","doi":"10.1144/petgeo2023-077","DOIUrl":"https://doi.org/10.1144/petgeo2023-077","url":null,"abstract":"Optimizing unconventional field development requires simultaneous optimization of well spacing and completion design. However, the conventional practice of using cross plots and sensitivity analysis via Monte Carlo simulations (MCS) for independent optimization of well spacing and completion design has proved inadequate for unconventional reservoirs. This is due to the inability of cross plots to capture non-linear cross-correlations between parameters affecting hydrocarbon production, and the computational expense and difficulty of Monte Carlo simulations. Recently, automated machine learning (AutoML) workflows have been used to tackle complex problems. However, applying AutoML workflows to engineering problems presents unique challenges, as achieving high accuracy in forecasting the physics of the problem is crucial. To address this issue, a new physics-informed AutoML workflow based on the TPOT open-source tool developed that guarantees the physical plausibility of the optimum model while minimizing human bias and uncertainty. The workflow has been implemented in a Marcellus Shale reservoir with over 1,500 wells to determine the optimal well spacing and completion design parameters for both the field and each well. The results show that using a shorter stage length (SSL) and a higher sand-to-water ratio (SWR) is preferable for this field, as it can increase cumulative gas production by up to 8%. Additionally, it is observed that fifty-percentile cumulative gas predictions are in close agreement with actual field productions.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Digitally enabled geoscience workflows: unlocking the power of our data collection available at:\u0000 https://www.lyellcollection.org/topic/collections/digitally-enabled-geoscience-workflows\u0000","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"20 11","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387097","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":"Fault-Seal Analysis in the Greater Bay du Nord Area, Flemish Pass Basin, Offshore Newfoundland","authors":"Asdrúbal Bernal","doi":"10.1144/petgeo2023-019","DOIUrl":"https://doi.org/10.1144/petgeo2023-019","url":null,"abstract":"A 3D subsurface structural model was built in a zone of the greater Bay du Nord Area, Flemish Pass Basin, offshore Newfoundland and Labrador, to carry out a post-drilled, fault-seal analysis in a multi-rift, geological complex setting; aiming to test fault-seal predictions, calibrate computed static fault zone attributes and estimate hydrocarbon contact depths. Hydrocarbon exploration campaigns in the greater Bay du Nord Area have primarily targeted rotated fault blocks, which often exhibit structural segmentation and compartmentalisation. A comprehensive approach that combines empirical and deterministic methods for static fault-seal analysis has been implemented. This approach provides insights into open, base, and tight fault-seal scenarios, aiding prospect evaluation in this region. Notably, Shale Gouge Ratios (SGRs) within the range of 16% to 25% serve as a crucial indicator of the transition between fault-rock sealing and non-sealing fault segments. Furthermore, it is emphasised the critical role of hydrodynamics when calibrating or evaluating fault sealing properties. In areas like the Greater Bay du Nord region, characterised by complex geology, it is imperative to regularly update fault-seal models. These updates should align with the availability of new subsurface data, comprehensive analyses, and an improved understanding of the petroleum system. Thematic collection: This article is part of the Fault and top seals 2022 collection available at: https://www.lyellcollection.org/topic/collections/fault-and-top-seals-2022","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"55 4","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139257709","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 analytical relationship between pore geometry and other pore space properties in carbonate rocks","authors":"B. Khadem, Mohammad Reza Saberi, Michel Krief, Hossein Rezaei Abbasi","doi":"10.1144/petgeo2023-028","DOIUrl":"https://doi.org/10.1144/petgeo2023-028","url":null,"abstract":"Although pore geometry plays an important role in carbonates rock physics modeling, few studies have been done on its analytic relationship with other pore space properties like pore space stiffness. We propose an analytical workflow based on the differential effective medium (DEM) to estimate the elastic properties of carbonate rocks. Then, the validity of our results is cross-checked with the Xu and Payne model on a real carbonate dataset. This workflow establishes a direct and quantitative link between the pore geometry of carbonate rock with its other pore space properties such as Biot's coefficient and pore space stiffness. This relationship can be, furthermore, utilized in defining rock physics templates (RPTs) to investigate the role of pore geometry on the rock elastic properties. Furthermore, we extended the Biot-Gassmann-Krief (BGK) model through our proposed workflow by establishing a theoretical framework to relate the main components of the BGK model to the pore geometry usually estimated in the laboratory or empirically. This can help to investigate the impact of fluid substitution on each of these main components. Our investigation suggests that the higher the Biot and Gassmann coefficients, the rock is more sensitive to fluid substitution. Moreover, this analytical workflow has been employed to examine the role of selecting different rotational spheroids (i.e., oblate and prolate) on the modeled velocities. Our results show that the modeled velocities depend on this selection in a way that prolate pores are less sensitive to the variations in their pore aspect ratio compared with the oblate pores.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"63 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139258009","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 Impact of Igneous Intrusions on Sedimentary Host Rocks: Insights from Field Outcrop and Subsurface Data","authors":"N.J. Mark, N. Schofield, D.A. Watson, S. Holford, S. Pugliese, D. Muirhead","doi":"10.1144/petgeo2022-086","DOIUrl":"https://doi.org/10.1144/petgeo2022-086","url":null,"abstract":"Pervasive igneous intrusive complexes have been identified in many sedimentary basins which are prospective for petroleum exploration and production. Seismic reflection and well data from these basins has characterised many of these igneous intrusions as forming networks of interconnected sills and dykes, with distinctive morphologies and typically cross-cutting sedimentary host rocks. Intrusions have also been identified in close proximity to many oil &amp; gas fields and exploration targets (e.g. Laggan-Tormore fields, Faroe Shetland Basin). It is therefore important to understand how igneous intrusions interact with sedimentary host rocks, specifically reservoir and source rock intervals, to determine the geological risk for petroleum exploration and production. The risks for petroleum exploration include low porosity and permeability within reservoirs, and overmaturity of source rocks, which are intruded. Additionally, reservoirs may be compartmentalised by low permeability igneous intrusions, inhibiting lateral and vertical migration of fluids. Based on a range of field studies and subsurface data, we demonstrate that sandstone porosity can be reduced by up to 20% (relative to background porosity) and the thermal maturity of organic rich claystones can be increased. The extent of host rock alteration away from igneous intrusions is highly variable and is commonly accompanied by mechanical compaction and fracturing of the host rock within the initial 10 to 20 cm of altered host rock. Reservoir quality and source rock maturity are key elements of the petroleum system and detrimental alteration of these intervals by igneous intrusions increases geological risk and should therefore be incorporated into any risk assessment of an exploration prospect or field development. Thematic collection: This article is part of the UKCS Atlantic Margin collection available at: https://www.lyellcollection.org/topic/collections/new-learning-from-exploration-and-development-in-the-ukcs-atlantic-margin","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"17 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135634334","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 distribution along open folds in Southern Tunisia: Implications for naturally fractured reservoirs","authors":"Ruaridh Y. Smith, Pierre-Olivier Bruna, Ahmed Nasri, Giovanni Bertotti","doi":"10.1144/petgeo2023-039","DOIUrl":"https://doi.org/10.1144/petgeo2023-039","url":null,"abstract":"Fracture networks play a critical role in fluid flow within reservoirs, and it is therefore important to understand the interactions and influences these networks have. Our study focusses on the Southern Chotts-Jeffara basin which hosts reservoirs within the Triassic, Permian and Ordovician units containing significant hydrocarbon accumulations. Recent developments on the structural understanding of the basin have proven a regional shortening phase occurring between the Permian and Jurassic forming open folds and a distributed fracture network. Analysis of late Palaeozoic and Mesozoic outcrops within the basin identify several sets of fractures (150/80; 212/86) and compressional structural features which support this shortening hypothesis. We integrate fracture data from surface analogues and subsurface analysis of advanced seismic attributes and well data through structural linking to form a 2D hybrid fracture model of the reservoirs in the region. Through analytical aperture modelling and numerical simulation, we find that the fractures orientated 212° in combination with large-scale fractures contribute significantly to the fluid flow orientation and potential reservoir permeability. Our presented fracture workflow and framework provides an insight in network characterisation within naturally fractured reservoirs of Tunisia and how certain structures form fluid pathways influence flow and production. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6904499","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"2012 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135636997","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":"Synthetic seismic stratigraphic interpretation from a sedimentological forward model in a pre-salt field of the Santos Basin","authors":"Pedro Benac, Desiree Liechoscki de Paula Faria, Alexandre Maul, Cleverson Guizan","doi":"10.1144/petgeo2023-069","DOIUrl":"https://doi.org/10.1144/petgeo2023-069","url":null,"abstract":"Forward modelling of sedimentary systems is a method that simulates sedimentation processes over geological time to generate a set of facies distributed in a depositional space. The objective of using forward modelling in this work was to build a 3D facies model from which a synthetic seismic simulation was generated, and then to analyse the relation of seismic-stratigraphic interpretations with the knowledge of the a priori generated sedimentological model. This modelling methodology was applied in a pre-salt field in the Santos Basin, Brazilian offshore, focused on the Barra Velha Formation. The modelling parameters used were: (i) the initial surface of bathymetric depth; (ii) the lake-level variation; (iii) the subsidence map; and (iv) the deposition rates of the facies. Average-constant of acoustic impedance values were assigned to each facies and a synthetic seismic was obtained. With the facies and synthetic models available, it was possible to analyse: (i) the distribution of thicknesses and proportion of facies by region; (ii) the vertical stacking pattern and lateral facies variation; (iii) the Wheeler distance × time diagram; and (iv) the seismic reflector patterns through the seismic facies classification. Through these analyses it was possible to better understand the possibilities and limitations of seismic stratigraphy as an interpretation auxiliary tool in pre-salt carbonate environments.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135667263","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":"Petroleum generation and migration through the Faroe-Shetland Basin - The role of Igneous Intrusions","authors":"A. Mangione, N. Schofield, S. Holford, C. Grove, C. Ellis, C. Forster, O. Schenk, D. Gardiner, B. Hedley, L. Broadley, J.R. Underhill","doi":"10.1144/petgeo2022-084","DOIUrl":"https://doi.org/10.1144/petgeo2022-084","url":null,"abstract":"Previous basin modelling of the Faroe-Shetland Basin (FSB, offshore UK) has suggested mid-Cretaceous petroleum generation, which predates the deposition of the working Paleogene reservoirs and traps. To justify the time discrepancy between generation, reservoir and trap formation, factors such as intermediary accumulations and overpressure have been invoked. However, across much of the FSB, the Cretaceous sequences that overly the Kimmeridgian source rock are heavily intruded by Paleogene-aged intrusions. Recent modelling has shown that the emplacement of the intrusions, coupled with lower radiogenic heat production from underlying basement, leads to estimates of petroleum generation occurring up to 40 Myr more recently than suggested by previous models. In this work, we seek to better understand the role that igneous intrusions have exerted on petroleum generation and migration in the FSB. Models with varying thicknesses of Paleogene intrusions are compared with those that consider the Cretaceous sequence as purely sedimentary (i.e. similar to assumptions in previous modelling). The estimated times of petroleum generation are compared with geochronological constraints on the ages of oils (i.e. 90-68 Ma) and deposition and formation of other petroleum system elements. By considering only the effect of igneous intrusions, the expulsion onset from the source rocks is retarded by up to approximately 12 Myr. In addition, our models show the impact of the intrusions on petroleum saturation and migration suggesting that intrusions have potentially compartmentalised the basin, trapping petroleum beneath or within the sill complex. Finally, our findings suggest that basin models in regions impacted by significant magmatism need to consider the impact of intrusions to more accurately constrain both petroleum generation and migration. Thematic collection: This article is part of the UKCS Atlantic Margin collection available at: https://www.lyellcollection.org/topic/collections/new-learning-from-exploration-and-development-in-the-ukcs-atlantic-margin","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134912044","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":"Radioactive Heat Production variations in the Faroe-Shetland Basin: key new heat production, geological and geochronological data for regional and local basin modelling","authors":"A. Finlay, D. Wray, Guy Comfort, Julian Moore","doi":"10.1144/petgeo2022-039","DOIUrl":"https://doi.org/10.1144/petgeo2022-039","url":null,"abstract":"\u0000 This study presents the results of a joint Chemostrat – APT study that aimed to produce a suite of Radioactive Heat Production (RHP) data for basement rocks in the Faroe Shetland Basin to enable more accurate basin modelling to be undertaken. To enable regional studies to be undertaken, the basement has been split into four zones based on similarities. Zone A is formed of high grade metamorphic basement from the Rockall trough (quads 154 & 164) southwest of the “Laxfordian front” postulated by Holdsworth et al., (2019). Zone B comprises granodioritic, tonalitic and dioritic Neoarchean aged (2700-2830 Ma) high grade metamorphic basement from the southwest of the Rona Ridge and Basin (wells 202/08-1, 204/15-2, 205/161, 205/21-1A, 206/7a-2, 206/08-2, 206/09-2 and 206/12-1) and northeast of the Laxfordian front. Zone C contains Neoarchean aged high grade metamorphic basement of a predominantly granitic and quartz rich granitoid composition from the northeast of the Rona Ridge (wells 207/01-3, 207/02-1, 208/23-1 and 208/26-1). Zone D differs from the rest of the material in this study in that it is Caledonian (∼460 Ma) granitic plutonic basement from Quads 209 (Ereland volcanic centre). Radioactive heat production values were derived from Potassium, Thorium and Uranium data produced from the analysis of eighty-four basement samples by ICP-OES and ICP-MS analysis. Each mapped basement zone was then assigned a mean radioactive heat production value for use in future basin modelling studies; Zone A = 0.21 µWm\u0000 3\u0000 , Zone B, 0.64 µWm\u0000 3\u0000 , zone C = 0.88 µWm\u0000 3\u0000 and zone D = 2.1 µWm\u0000 3\u0000 .\u0000 \u0000 \u0000 Thematic collection:\u0000 This article is part of the UKCS Atlantic Margin collection available at:\u0000 https://www.lyellcollection.org/topic/collections/new-learning-from-exploration-and-development-in-the-ukcs-atlantic-margin\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6771540\u0000","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49452641","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}