Seismic modeling is an important step in the process used for imaging Earth subsurface. Current applications require accurate models associated with solutions of the wave propagation equation in real media. Unfortunately, it is common not to find in the technical literature deep discussions on the impact of specific details associated with the physical modeling of some crucial ingredients of the process, such as seismic source term and boundary conditions. In this paper, we discuss some issues related to the modeling of wave propagation in visco-acoustic media using finite differences. We focus our attention on two major elements of the modeling problem that are associated to the source term and the boundary conditions. We show that the source term can be modeled using a scale parameter that controls the spread of energy and shows that this parameter is a function of frequency and position of the source. As to boundary conditions, we show that Perfectly Matched Layer (PML) parameters are also frequency dependent. For both cases, seismic source scale parameter and PML model parameters we provide values and functions that optimize the performance of the approach for problems where visco-acoustic wave propagation is required. Frequency domain Full Waveform Inversion (FWI), or Reverse Time Migration (RTM) processes that depend fundamentally on the appropriate modeling of the wave-field are potential fields of application of these results.
{"title":"Numerical considerations on the modeling of source and boundary conditions for the frequency domain visco-acoustic wave equation solution","authors":"S. Avendaño, Juan Carlos Muñoz Cuartas","doi":"10.29047/01225383.80","DOIUrl":"https://doi.org/10.29047/01225383.80","url":null,"abstract":"Seismic modeling is an important step in the process used for imaging Earth subsurface. Current applications require accurate models associated with solutions of the wave propagation equation in real media. Unfortunately, it is common not to find in the technical literature deep discussions on the impact of specific details associated with the physical modeling of some crucial ingredients of the process, such as seismic source term and boundary conditions. In this paper, we discuss some issues related to the modeling of wave propagation in visco-acoustic media using finite differences. We focus our attention on two major elements of the modeling problem that are associated to the source term and the boundary conditions. We show that the source term can be modeled using a scale parameter that controls the spread of energy and shows that this parameter is a function of frequency and position of the source. As to boundary conditions, we show that Perfectly Matched Layer (PML) parameters are also frequency dependent. For both cases, seismic source scale parameter and PML model parameters we provide values and functions that optimize the performance of the approach for problems where visco-acoustic wave propagation is required. Frequency domain Full Waveform Inversion (FWI), or Reverse Time Migration (RTM) processes that depend fundamentally on the appropriate modeling of the wave-field are potential fields of application of these results.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90909256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Abreo, Ana Beatríz Ramírez Silva, Oscar Mauricio Reyes Torres
The second order scattering information provided by the Hessian matrix and its inverse plays an important role in both, parametric inversion and uncertainty quantification. On the one hand, for parameter inversion, the Hessian guides the descent direction such that the cost function minimum is reached with less iterations. On the other hand, it provides a posteriori information of the probability distribution of the parameters obtained after full waveform inversion, as a function of the a priori probability distribution information. Nevertheless, the computational cost of the Hessian matrix represents the main obstacle in the state-of-the-art for practical use of this matrix from synthetic or real data. The second order adjoint state theory provides a strategy to compute the exact Hessian matrix, reducing its computational cost, because every column of the matrix can be obtained by performing two forward and two backward propagations. In this paper, we first describe an approach to compute the exact Hessian matrix for the acoustic wave equation with constant density. We then provide an analysis of the use of the Hessian matrix for uncertainty quantification of the full waveform inversion of the velocity model for a synthetic example, using the 2D acoustic and isotropic wave equation operator in time.
{"title":"A GPU implementation of the second order adjoint state theory to quantify the uncertainty on FWI results","authors":"S. Abreo, Ana Beatríz Ramírez Silva, Oscar Mauricio Reyes Torres","doi":"10.29047/01225383.86","DOIUrl":"https://doi.org/10.29047/01225383.86","url":null,"abstract":"The second order scattering information provided by the Hessian matrix and its inverse plays an important role in both, parametric inversion and uncertainty quantification. On the one hand, for parameter inversion, the Hessian guides the descent direction such that the cost function minimum is reached with less iterations. On the other hand, it provides a posteriori information of the probability distribution of the parameters obtained after full waveform inversion, as a function of the a priori probability distribution information. \u0000Nevertheless, the computational cost of the Hessian matrix represents the main obstacle in the state-of-the-art for practical use of this matrix from synthetic or real data. The second order adjoint state theory provides a strategy to compute the exact Hessian matrix, reducing its computational cost, because every column of the matrix can be obtained by performing two forward and two backward propagations. \u0000In this paper, we first describe an approach to compute the exact Hessian matrix for the acoustic wave equation with constant density. We then provide an analysis of the use of the Hessian matrix for uncertainty quantification of the full waveform inversion of the velocity model for a synthetic example, using the 2D acoustic and isotropic wave equation operator in time.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89252753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Jim'enez, Juan Carlos Muñoz Cuartas, S. Avendaño
In this work we present a formalism that intends to solve the problem of modeling wave propagation in the context of seismic inversion. The formalism is based on the linear perturbation theory of Cauchy’s equations. Based on the foregoing, we derived an equivalent Helmholtz equation for the propagation of waves in a variable density media. Then, we defined a solution, by using the boundary conditions on a half plane. This solution is of an integral nature and resembles expansion in a Neumann series. We implemented the solution of the first terms in the series, considering only the incident wavefield and neglecting the reflections. We show how this approximation works in different media that include lateral in homogeneities in the velocity. The method presented hereunder is intended as a first step in the modelling process for the full wavefield, to be used in seismic inversion methods, Full Waveform Inversion, for example.
{"title":"Integral modelling of propagation of incident waves in a laterally varying medium: An exploration in the frequency domain","authors":"A. Jim'enez, Juan Carlos Muñoz Cuartas, S. Avendaño","doi":"10.29047/01225383.79","DOIUrl":"https://doi.org/10.29047/01225383.79","url":null,"abstract":"In this work we present a formalism that intends to solve the problem of modeling wave propagation in the context of seismic inversion. The formalism is based on the linear perturbation theory of Cauchy’s equations. Based on the foregoing, we derived an equivalent Helmholtz equation for the propagation of waves in a variable density media. Then, we defined a solution, by using the boundary conditions on a half plane. This solution is of an integral nature and resembles expansion in a Neumann series. We implemented the solution of the first terms in the series, considering only the incident wavefield and neglecting the reflections. We show how this approximation works in different media that include lateral in homogeneities in the velocity. The method presented hereunder is intended as a first step in the modelling process for the full wavefield, to be used in seismic inversion methods, Full Waveform Inversion, for example.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78847806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Florez, Sergio Alberto Abreo Carrillo, Ana Beatríz Ramírez Silva
Full Waveform Inversion (FWI) schemes are gradually becoming more common in the oil and gas industry, as a new tool for studying complex geological zones, based on their reliability for estimating velocity models. FWI is a non-linear inversion method that iteratively estimates subsurface characteristics such as seismic velocity, starting from an initial velocity model and the preconditioned data acquired. Blended sources have been used in marine seismic acquisitions to reduce acquisition costs, reducing the number of times that the vessel needs to cross the exploration delineation trajectory. When blended or simultaneous without previous de-blending or separation, stage data are used in the reconstruction of the velocity model with the FWI method, and the computational time is reduced. However, blended data implies overlapping single shot-gathers, producing interference that affects the result of seismic approaches, such as FWI or seismic image migration. In this document, an encoding strategy is developed, which reduces the overlap areas within the blended data to improve the final velocity model with the FWI method.
{"title":"Optimal coding of blended seismic sources for 2D full waveform inversion in time","authors":"K. Florez, Sergio Alberto Abreo Carrillo, Ana Beatríz Ramírez Silva","doi":"10.29047/01225383.78","DOIUrl":"https://doi.org/10.29047/01225383.78","url":null,"abstract":"Full Waveform Inversion (FWI) schemes are gradually becoming more common in the oil and gas industry, as a new tool for studying complex geological zones, based on their reliability for estimating velocity models. FWI is a non-linear inversion method that iteratively estimates subsurface characteristics such as seismic velocity, starting from an initial velocity model and the preconditioned data acquired. \u0000Blended sources have been used in marine seismic acquisitions to reduce acquisition costs, reducing the number of times that the vessel needs to cross the exploration delineation trajectory. When blended or simultaneous without previous de-blending or separation, stage data are used in the reconstruction of the velocity model with the FWI method, and the computational time is reduced. However, blended data implies overlapping single shot-gathers, producing interference that affects the result of seismic approaches, such as FWI or seismic image migration. \u0000In this document, an encoding strategy is developed, which reduces the overlap areas within the blended data to improve the final velocity model with the FWI method.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74788469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
César-Augusto Arias Chica, D. Abreo, S. Abreo, Luis Fernando Duque Gómez, Ana Beatríz Ramírez Silva
Full waveform inversion (FWI) has been recently used to estimate subsurface parameters, such as velocity models. This method, however, has a number of drawbacks when applied to zones with rugged topography due to the forced application of a Cartesian mesh on a curved surface. In this work, we present a simple coordinate transformation that enables the construction of a curved mesh. The proposed transformation is more suitable for rugged surfaces and it allows mapping a physical curved domain into a uniform rectangular grid, where acoustic FWI can be applied in the traditional way by introducing a modified Laplacian. We prove that the proposed approximation can have a wide range of applications, producing precise near-surface velocity models without increasing the computing time of the FWI.
{"title":"Full Waveform Inversion in generalized coordinates for zones of curved topography","authors":"César-Augusto Arias Chica, D. Abreo, S. Abreo, Luis Fernando Duque Gómez, Ana Beatríz Ramírez Silva","doi":"10.29047/01225383.84","DOIUrl":"https://doi.org/10.29047/01225383.84","url":null,"abstract":"Full waveform inversion (FWI) has been recently used to estimate subsurface parameters, such as velocity models. This method, however, has a number of drawbacks when applied to zones with rugged topography due to the forced application of a Cartesian mesh on a curved surface. In this work, we present a simple coordinate transformation that enables the construction of a curved mesh. The proposed transformation is more suitable for rugged surfaces and it allows mapping a physical curved domain into a uniform rectangular grid, where acoustic FWI can be applied in the traditional way by introducing a modified Laplacian. We prove that the proposed approximation can have a wide range of applications, producing precise near-surface velocity models without increasing the computing time of the FWI.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79309335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Jairo, Naranjo-Vesga Julián-Francisco, Mantilla-Figueroa Luis-Carlos
Studies conducted by means of petrography, cathodoluminescence, SEM, fluid inclusion and REE geochemistry in core samples from the Rosablanca Formation in the Mesa de Los Santos sector, identified two types of material: the host rock classified as Packstones and Grainstones, and veins that texturally expose three types of filling (blocky texture, blocky elongate texture, fibrous texture). Diagenesis is characterized by dissolution, carbonate cement precipitation, compaction, fracturing and fluid circulation through fractures during at least three episodes; these diagenetic processes were contemporaneous with the distensive and compressive tectonic regimes regionally dominant during the Cretaceous, Paleogene and Neogene in the study area. The fluids that generated the different types of texture inside the veins were brines that belonged to the H2O – NaCl – CaCl2 system, with salinities between 0.03 – 12.96 % wt eq NaCl, derived from the Rosablanca Formation that was deposited under oxic conditions, retaining their marine character and implying an autochthonousorigin for the REE present in the veins. The conditions of entrapment for fluid inclusions during the early event were heterogeneous, arising from an immiscible mixture of brines andhydrocarbons, while in the second, they were homogeneous with later post-entrapment processes.later post-entrapment processes.
通过岩石学、阴极发光、扫描电镜、流体包裹体和稀土元素地球化学研究，对Mesa de Los Santos地区Rosablanca组岩心样品进行了研究，确定了两种类型的物质:被分类为Packstones和Grainstones的寄主岩石，以及在结构上暴露出三种充填类型(块状结构、块状细长结构、纤维状结构)的脉体。成岩作用的特征是溶蚀作用、碳酸盐胶结物沉淀作用、压实作用、压裂作用和流体通过裂缝的循环作用至少3次;这些成岩作用与研究区白垩纪、古近纪和新近纪区域主导的扩张和挤压构造体制是同时期的。在脉内形成不同类型纹理的流体为H2O - NaCl - CaCl2体系的盐水，盐度在0.03 ~ 12.96% (wt eq NaCl)之间，来自Rosablanca组，在缺氧条件下沉积，保留了其海洋特征，表明脉内REE存在本地来源。在早期事件中，流体包裹体的包裹条件是不均匀的，这是由盐水和碳氢化合物的不混相混合物引起的，而在第二次事件中，它们是均匀的，这是后期的包裹过程。之后的捕获过程。
{"title":"Fluid Inclusions and Rare Earth Elements (REE) analysis in calcite veins: Tectonic - diagenesis interaction in the Rosablanca formation, Mesa de los Santos sector, eastern cordillera, Colombia","authors":"C. Jairo, Naranjo-Vesga Julián-Francisco, Mantilla-Figueroa Luis-Carlos","doi":"10.29047/01225383.89","DOIUrl":"https://doi.org/10.29047/01225383.89","url":null,"abstract":"Studies conducted by means of petrography, cathodoluminescence, SEM, fluid inclusion and REE geochemistry in core samples from the Rosablanca Formation in the Mesa de Los Santos sector, identified two types of material: the host rock classified as Packstones and Grainstones, and veins that texturally expose three types of filling (blocky texture, blocky elongate texture, fibrous texture). Diagenesis is characterized by dissolution, carbonate cement precipitation, compaction, fracturing and fluid circulation through fractures during at least three episodes; these diagenetic processes were contemporaneous with the distensive and compressive tectonic regimes regionally dominant during the Cretaceous, Paleogene and Neogene in the study area. The fluids that generated the different types of texture inside the veins were brines that belonged to the H2O – NaCl – CaCl2 system, with salinities between 0.03 – 12.96 % wt eq NaCl, derived from the Rosablanca Formation that was deposited under oxic conditions, retaining their marine character and implying an autochthonousorigin for the REE present in the veins. The conditions of entrapment for fluid inclusions during the early event were heterogeneous, arising from an immiscible mixture of brines andhydrocarbons, while in the second, they were homogeneous with later post-entrapment processes.later post-entrapment processes.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85473789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. F. Colmenares-Quintero, L. Latorre-Noguera, J. Colmenares-Quintero, J. Dibdiakova
The study carried out here aims to determine the advantage of using in-situ electricity generation facilities versus conventional generators, being evaluated from the environmental point of view. For this, an environmental analysis on the production of CO2 has been applied to two scenarios of electricity generation for a residential building in Medellin city (Colombia). The first one refers to La Sierra thermo-electric plant located in La Sierra, municipality of Puerto Nare, in the Antioquiashire, which is the most efficient plant in Colombian thermal generation. The second comparison scenario refers to the annual operation of a micro-cogeneration facility, which satisfies the building’s hot water and electrical energy needs. Using the capabilities of the TRNSYS v17® energy simulation software and the emission equations available in the public domain, the comparative environmental analysis is carried out between one and the other for the same load. The losses in electric transmission are assumed to be 10%. This analysis has shown a difference of more than 50% in emissions generation, with the main cause being the amount of fuel used, which for both cases is natural gas. On the other hand, this study shows the environmental advantages in the use of in-situ generators, decreasing transmission losses.
在这里进行的研究旨在确定使用就地发电设施与传统发电机的优势，并从环境的角度进行评估。为此，对二氧化碳产生的环境分析已应用于麦德林市(哥伦比亚)一座住宅楼的两种发电方案。第一个是位于Antioquiashire Puerto Nare市La Sierra的La Sierra热电厂，这是哥伦比亚火力发电效率最高的电厂。第二个比较方案是指微型热电联产设备的年度运行，该设备满足建筑物的热水和电能需求。利用TRNSYS v17®能源模拟软件的功能和公共领域可用的排放方程，在相同的负载下，在一个和另一个之间进行比较环境分析。假设电力传输中的损耗为10%。该分析显示，两者的排放量差异超过50%，主要原因是使用的燃料数量，两种情况下都是天然气。另一方面，本研究显示了使用原位发电机的环境优势，减少了传输损耗。
{"title":"Techno-environmental assessment of a micro-cogeneration system based on natural gas for residential application","authors":"R. F. Colmenares-Quintero, L. Latorre-Noguera, J. Colmenares-Quintero, J. Dibdiakova","doi":"10.29047/01225383.97","DOIUrl":"https://doi.org/10.29047/01225383.97","url":null,"abstract":"The study carried out here aims to determine the advantage of using in-situ electricity generation facilities versus conventional generators, being evaluated from the environmental point of view. For this, an environmental analysis on the production of CO2 has been applied to two scenarios of electricity generation for a residential building in Medellin city (Colombia). The first one refers to La Sierra thermo-electric plant located in La Sierra, municipality of Puerto Nare, in the Antioquiashire, which is the most efficient plant in Colombian thermal generation. The second comparison scenario refers to the annual operation of a micro-cogeneration facility, which satisfies the building’s hot water and electrical energy needs. Using the capabilities of the TRNSYS v17® energy simulation software and the emission equations available in the public domain, the comparative environmental analysis is carried out between one and the other for the same load. The losses in electric transmission are assumed to be 10%. This analysis has shown a difference of more than 50% in emissions generation, with the main cause being the amount of fuel used, which for both cases is natural gas. On the other hand, this study shows the environmental advantages in the use of in-situ generators, decreasing transmission losses.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"573 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88013607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Aptian-Albian Caballos Formation is a proven reservoir in the oil producing basins of the Upper Magdalena Valley and Putumayo (Colombia), characterized by wide variation in its petrophysical properties. Integrated provenance, diagenetic and basic petrophysical analyses are presented from two stratigraphic sections of the Caballos Formation in the Upper Magdalena Valley (Ocal and Cobre creeks) in order to test regional geological models, and to relate compositional and diagenetic factors with the reservoir quality.Sandstones from the Caballos Formation document a change from texturally immature- subarkoses, litharenites to quartz arenites. High quartz contents, the presence of feldspar, sedimentary, metamorphic and volcanic lithic suggest mixed provenance, with a major contribution from sedimentary sources. U-Pb dating of detrital zircons reveals age populations that include contributions from Precambrian, Permian, Triassic and Jurassic rocks. These data, together with the compositional trends, suggest that source areas likely include adjacent massifs from the eastern segment of the Upper Magdalena Valley with similar compositional andtemporal characteristics (Garzón and Macarena Massifs for the southeastern Ocal Section, and the Upper Magdalena Valley massifs and the eastern flank of the Central Cordillera; Ocal Section). The changes in compositional features and detrital geochronology between the upper and lower members of both sections suggest a change in source areas, associated with the erosion and depletion of adjacent uplifts, and the increasing dominance of more distal eastern and western sources, which reflect the end of tectonic instability and the deepening of the basin.The presence of quartz, feldspar, and lithic rock fragments have a major impact on the porosity and permeability of Caballos Formation sandstones. Porosity values are lower in the lower member of the Caballos Formation where diagenesis has altered abundant feldspar and lithic rock fragments to authigenic porefilling clays. Higher porosity and permeability values found in the upper member of the Caballos correspond to a combination of higher quartz contents and the dissolution of meta-stable components during late diagenesis.
{"title":"Provenance and diagenesis from two stratigraphic sections of the lower cretaceous Caballos formation in the upper Magdalena valley: Geological and reservoir quality implications","authors":"E. Duarte","doi":"10.29047/01225383.101","DOIUrl":"https://doi.org/10.29047/01225383.101","url":null,"abstract":"The Aptian-Albian Caballos Formation is a proven reservoir in the oil producing basins of the Upper Magdalena Valley and Putumayo (Colombia), characterized by wide variation in its petrophysical properties. Integrated provenance, diagenetic and basic petrophysical analyses are presented from two stratigraphic sections of the Caballos Formation in the Upper Magdalena Valley (Ocal and Cobre creeks) in order to test regional geological models, and to relate compositional and diagenetic factors with the reservoir quality.Sandstones from the Caballos Formation document a change from texturally immature- subarkoses, litharenites to quartz arenites. High quartz contents, the presence of feldspar, sedimentary, metamorphic and volcanic lithic suggest mixed provenance, with a major contribution from sedimentary sources. U-Pb dating of detrital zircons reveals age populations that include contributions from Precambrian, Permian, Triassic and Jurassic rocks. These data, together with the compositional trends, suggest that source areas likely include adjacent massifs from the eastern segment of the Upper Magdalena Valley with similar compositional andtemporal characteristics (Garzón and Macarena Massifs for the southeastern Ocal Section, and the Upper Magdalena Valley massifs and the eastern flank of the Central Cordillera; Ocal Section). The changes in compositional features and detrital geochronology between the upper and lower members of both sections suggest a change in source areas, associated with the erosion and depletion of adjacent uplifts, and the increasing dominance of more distal eastern and western sources, which reflect the end of tectonic instability and the deepening of the basin.The presence of quartz, feldspar, and lithic rock fragments have a major impact on the porosity and permeability of Caballos Formation sandstones. Porosity values are lower in the lower member of the Caballos Formation where diagenesis has altered abundant feldspar and lithic rock fragments to authigenic porefilling clays. Higher porosity and permeability values found in the upper member of the Caballos correspond to a combination of higher quartz contents and the dissolution of meta-stable components during late diagenesis.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88159216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, n-heptane insoluble fractions (asphaltenes) from six crude oils were analyzed by means of Fourier-transform ion cyclotron resonance mass spectrometry (FTICR MS) using both positive Atmospheric Pressure Photo Ionization (+) APPI and negative Electro- Spray Ionization (-) ESI in order to understand their water-oil emulsion stabilization capability on a molecular level basis. Through (+) APPI it was possible to obtain an overview of samples composition. By sorting as nitrogen sulfur and oxygen containing compounds, it was possible to compositionally distinguish the asphaltenes. Through (-) ESI, several differences were also observed by grouping the classes as oxygen (NxOy+NxOySz+Oy+OySz) and non oxygen containing classes (Nx+NxSz). The interactions of these two groups of compounds must be considered in order to understand the water-oil emulsion stability. It implies that the cores where nitrogen and sulfur are part may interact via π-π stacking, while the oxygen containing compounds may interact either via hydrogen bonding or via dipole forces with the aromatic aggregates (highly polarizable), forming potentially surface active aggregates. Thus, the rate between these two families of compounds may determine the surfactant character of asphaltenes at the water-oil interface. Bearing this in mind, an emulsion stability coefficient was proposed based on the relative abundances of some families of compounds detected by (-) ESI-FTICR-MS to explain the crude oils’ tendency to form emulsions.
{"title":"Finding a relationship between the composition and the emulsifying character of asphaltenes through FTICR-MS","authors":"F. Rojas-Ruiz, J. Orrego-Ruiz","doi":"10.29047/01225383.90","DOIUrl":"https://doi.org/10.29047/01225383.90","url":null,"abstract":"In this work, n-heptane insoluble fractions (asphaltenes) from six crude oils were analyzed by means of Fourier-transform ion cyclotron resonance mass spectrometry (FTICR MS) using both positive Atmospheric Pressure Photo Ionization (+) APPI and negative Electro- Spray Ionization (-) ESI in order to understand their water-oil emulsion stabilization capability on a molecular level basis. Through (+) APPI it was possible to obtain an overview of samples composition. By sorting as nitrogen sulfur and oxygen containing compounds, it was possible to compositionally distinguish the asphaltenes. Through (-) ESI, several differences were also observed by grouping the classes as oxygen (NxOy+NxOySz+Oy+OySz) and non oxygen containing classes (Nx+NxSz). The interactions of these two groups of compounds must be considered in order to understand the water-oil emulsion stability. It implies that the cores where nitrogen and sulfur are part may interact via π-π stacking, while the oxygen containing compounds may interact either via hydrogen bonding or via dipole forces with the aromatic aggregates (highly polarizable), forming potentially surface active aggregates. Thus, the rate between these two families of compounds may determine the surfactant character of asphaltenes at the water-oil interface. Bearing this in mind, an emulsion stability coefficient was proposed based on the relative abundances of some families of compounds detected by (-) ESI-FTICR-MS to explain the crude oils’ tendency to form emulsions.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76376337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Estimating the volumetric flow of cuttings and cavings that are extracted and transported by the drilling mud into the flow line while drilling a well is of major interest to for drillers so that they can understand the drilling conditions and maintain the wellbore stability. In this paper, a new method to estimate the volumetric flow of cavings via the Doppler effect is proposed. The proposed method is a non-invasive method that uses two piezo-electric acoustic sensors located on the flow line, one acting as an emitter and the other acting as a receiver. The system device estimates cavings and cuttings by measuring the mud and solids flow on a real-time basis. Results obtained at a laboratory experimental level reflected a maximum volumetric-flow error of 10.5% for small-sized cavings and 34,7% for large-sized cavings. According to those results, the method may be suitable for estimating cavingvolumetric-flow with acoustical techniques at the flow line while drilling and it might be used as a real-time operation method to evaluate wellbore stability.
{"title":"Estimation of Caving volumetric-flow using the ultrasonic Doppler method","authors":"Jenny-Mabel Carvajal-Jiménez","doi":"10.29047/01225383.92","DOIUrl":"https://doi.org/10.29047/01225383.92","url":null,"abstract":"Estimating the volumetric flow of cuttings and cavings that are extracted and transported by the drilling mud into the flow line while drilling a well is of major interest to for drillers so that they can understand the drilling conditions and maintain the wellbore stability. In this paper, a new method to estimate the volumetric flow of cavings via the Doppler effect is proposed. The proposed method is a non-invasive method that uses two piezo-electric acoustic sensors located on the flow line, one acting as an emitter and the other acting as a receiver. The system device estimates cavings and cuttings by measuring the mud and solids flow on a real-time basis. Results obtained at a laboratory experimental level reflected a maximum volumetric-flow error of 10.5% for small-sized cavings and 34,7% for large-sized cavings. According to those results, the method may be suitable for estimating cavingvolumetric-flow with acoustical techniques at the flow line while drilling and it might be used as a real-time operation method to evaluate wellbore stability.","PeriodicalId":10745,"journal":{"name":"CT&F - Ciencia, Tecnología y Futuro","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88072135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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