M. Jackson, M. Gudmundsson, T. Weisenberger, J. M. Rhodes, A. Stefánsson, B. Kleine, P. Lippert, J. Marquardt, H. Reynolds, J. Kück, V. T. Marteinsson, P. Vannier, W. Bach, A. Barich, Pauline Bergsten, J. Bryce, P. Cappelletti, S. Couper, M. Fahnestock, C. Gorny, C. Grimaldi, Marco Groh, A. Gudmundsson, Á. T. Gunnlaugsson, C. Hamlin, Thórdís Högnadóttir, K. Jónasson, S. Jónsson, S. Jørgensen, A. Klonowski, B. Marshall, E. Massey, J. McPhie, J. Moore, E. Ólafsson, S. L. Onstad, V. Perez, Simon Prause, S. P. Snorrason, Andreas Türke, J. White, B. Zimanowski
Abstract. The 2017 Surtsey Underwater volcanic System for Thermophiles, Alteration processes and INnovative concretes (SUSTAIN) drilling project at Surtsey volcano, sponsored in part by the International Continental Scientific Drilling Program (ICDP), provides precise observations of the hydrothermal, geochemical, geomagnetic, and microbiological changes that have occurred in basaltic tephra and minor intrusions since explosive and effusive eruptions produced the oceanic island in 1963–1967. Two vertically cored boreholes, to 152 and 192 m below the surface, were drilled using filtered, UV-sterilized seawater circulating fluid to minimize microbial contamination. These cores parallel a 181 m core drilled in 1979. Introductory investigations indicate changes in material properties and whole-rock compositions over the past 38 years. A Surtsey subsurface observatory installed to 181 m in one vertical borehole holds incubation experiments that monitor in situ mineralogical and microbial alteration processes at 25–124 ∘C. A third cored borehole, inclined 55∘ in a 264∘ azimuthal direction to 354 m measured depth, provides further insights into eruption processes, including the presence of a diatreme that extends at least 100 m into the seafloor beneath the Surtur crater. The SUSTAIN project provides the first time-lapse drilling record into a very young oceanic basaltic volcano over a range of temperatures, 25–141 ∘C from 1979 to 2017, and subaerial and submarine hydrothermal fluid compositions. Rigorous procedures undertaken during the drilling operation protected the sensitive environment of the Surtsey Natural Preserve.
{"title":"SUSTAIN drilling at Surtsey volcano, Iceland, tracks hydrothermal and microbiological interactions in basalt 50 years after eruption","authors":"M. Jackson, M. Gudmundsson, T. Weisenberger, J. M. Rhodes, A. Stefánsson, B. Kleine, P. Lippert, J. Marquardt, H. Reynolds, J. Kück, V. T. Marteinsson, P. Vannier, W. Bach, A. Barich, Pauline Bergsten, J. Bryce, P. Cappelletti, S. Couper, M. Fahnestock, C. Gorny, C. Grimaldi, Marco Groh, A. Gudmundsson, Á. T. Gunnlaugsson, C. Hamlin, Thórdís Högnadóttir, K. Jónasson, S. Jónsson, S. Jørgensen, A. Klonowski, B. Marshall, E. Massey, J. McPhie, J. Moore, E. Ólafsson, S. L. Onstad, V. Perez, Simon Prause, S. P. Snorrason, Andreas Türke, J. White, B. Zimanowski","doi":"10.5194/SD-25-35-2019","DOIUrl":"https://doi.org/10.5194/SD-25-35-2019","url":null,"abstract":"Abstract. The 2017 Surtsey Underwater volcanic System for Thermophiles, Alteration\u0000processes and INnovative concretes (SUSTAIN) drilling project at Surtsey\u0000volcano, sponsored in part by the International Continental Scientific\u0000Drilling Program (ICDP), provides precise observations of the hydrothermal,\u0000geochemical, geomagnetic, and microbiological changes that have occurred in\u0000basaltic tephra and minor intrusions since explosive and effusive eruptions\u0000produced the oceanic island in 1963–1967. Two vertically cored boreholes, to\u0000152 and 192 m below the surface, were drilled using filtered, UV-sterilized\u0000seawater circulating fluid to minimize microbial contamination. These cores\u0000parallel a 181 m core drilled in 1979. Introductory investigations indicate\u0000changes in material properties and whole-rock compositions over the past\u000038 years. A Surtsey subsurface observatory installed to 181 m in one\u0000vertical borehole holds incubation experiments that monitor in situ\u0000mineralogical and microbial alteration processes at 25–124 ∘C. A\u0000third cored borehole, inclined 55∘ in a 264∘ azimuthal\u0000direction to 354 m measured depth, provides further insights into eruption\u0000processes, including the presence of a diatreme that extends at least 100 m\u0000into the seafloor beneath the Surtur crater. The SUSTAIN project provides the\u0000first time-lapse drilling record into a very young oceanic basaltic volcano\u0000over a range of temperatures, 25–141 ∘C from 1979 to 2017, and\u0000subaerial and submarine hydrothermal fluid compositions. Rigorous procedures\u0000undertaken during the drilling operation protected the sensitive environment\u0000of the Surtsey Natural Preserve.\u0000","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"133 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2019-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73961971","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}
Pub Date : 2018-10-31DOI: 10.5772/intechopen.75827
Xuyue Chen, Jin Yang, D. Gao
{"title":"Drilling Performance Optimization Based on Mechanical Specific Energy Technologies","authors":"Xuyue Chen, Jin Yang, D. Gao","doi":"10.5772/intechopen.75827","DOIUrl":"https://doi.org/10.5772/intechopen.75827","url":null,"abstract":"","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"39 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74379153","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}
Pub Date : 2018-10-31DOI: 10.5772/INTECHOPEN.75712
Junyue Tang, Q. Quan, Shengyuan Jiang, Jieneng Liang, Z. Deng
The robotic technology, especially the intelligent robotics that can autonomously conduct numerous dangerous and uncertain tasks, has been widely applied to planetary explorations. Similar to terrestrial mining, before landing on planets or building planetary constructions, a drilling and coring activity should be first conducted to investigate the in-situ geological information. Given the technical advantages of unmanned robotics, utilizing an autonomous drill tool to acquire the planetary soil sample may be the most reliable and cost-effective solution. However, due to several unique challenges existed in unmanned drilling and coring activities, such as long-distance time delay, uncertain drilling formations, limited sensor resources, etc., it is indeed necessary to conduct researches to improve system’s adaptability to the complicated geological formations. Taking drill tool’s power consumption and soil’s coring morphology into account, this chapter proposed a drilling and coring characteristics online monitoring method to investigate suitable drilling parameters for different formations. Meanwhile, by apply - ing pattern recognition techniques to classify different types of potential soil or rocks, a drillability classification model is built accurately to identify the current drilling forma - tion. By combining suitable drilling parameters with the recognized drillability levels, a closed-loop drilling strategy is established finally, which can be applied to future inter - planetary exploration.
{"title":"Intelligent Drilling and Coring Technologies for Unmanned Interplanetary Exploration","authors":"Junyue Tang, Q. Quan, Shengyuan Jiang, Jieneng Liang, Z. Deng","doi":"10.5772/INTECHOPEN.75712","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75712","url":null,"abstract":"The robotic technology, especially the intelligent robotics that can autonomously conduct numerous dangerous and uncertain tasks, has been widely applied to planetary explorations. Similar to terrestrial mining, before landing on planets or building planetary constructions, a drilling and coring activity should be first conducted to investigate the in-situ geological information. Given the technical advantages of unmanned robotics, utilizing an autonomous drill tool to acquire the planetary soil sample may be the most reliable and cost-effective solution. However, due to several unique challenges existed in unmanned drilling and coring activities, such as long-distance time delay, uncertain drilling formations, limited sensor resources, etc., it is indeed necessary to conduct researches to improve system’s adaptability to the complicated geological formations. Taking drill tool’s power consumption and soil’s coring morphology into account, this chapter proposed a drilling and coring characteristics online monitoring method to investigate suitable drilling parameters for different formations. Meanwhile, by apply - ing pattern recognition techniques to classify different types of potential soil or rocks, a drillability classification model is built accurately to identify the current drilling forma - tion. By combining suitable drilling parameters with the recognized drillability levels, a closed-loop drilling strategy is established finally, which can be applied to future inter - planetary exploration.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"111 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77814416","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}
Pub Date : 2018-10-31DOI: 10.5772/INTECHOPEN.76903
Omogbolahan S. Ahmed, A. Adeniran, A. Samsuri
The prediction and the optimization of the rate of penetration (ROP), an important mea- sure of drilling performance, have increasingly generated great interest. Several empirical techniques have been explored in the literature for the prediction and the optimization of ROP. In this study, four commonly used artificial intelligence (AI) algorithms are explored for the prediction of ROP based on the hydromechanical specific energy (HMSE) ROP model parameters. The AIs explored are the artificial neural network (ANN), extreme learning machine (ELM), support vector regression (SVR), and least-square support vector regression (LS-SVR). All the algorithms provided results with accuracy within acceptable range. The utilization of HMSE in selecting drilling variables for the prediction models provided an improved and consistent methodology of predicting ROP with drilling efficiency optimization objectives. This is valuable from an operational point of view, because it provides a reference point for measuring drilling efficiency and performance of the drilling process in terms of energy input and corresponding output in terms of ROP. The real-time drilling data utilized are must-haves, easily acquired, accessible, and controllable during drilling operations.
{"title":"Rate of Penetration Prediction Utilizing Hydromechanical Specific Energy","authors":"Omogbolahan S. Ahmed, A. Adeniran, A. Samsuri","doi":"10.5772/INTECHOPEN.76903","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.76903","url":null,"abstract":"The prediction and the optimization of the rate of penetration (ROP), an important mea- sure of drilling performance, have increasingly generated great interest. Several empirical techniques have been explored in the literature for the prediction and the optimization of ROP. In this study, four commonly used artificial intelligence (AI) algorithms are explored for the prediction of ROP based on the hydromechanical specific energy (HMSE) ROP model parameters. The AIs explored are the artificial neural network (ANN), extreme learning machine (ELM), support vector regression (SVR), and least-square support vector regression (LS-SVR). All the algorithms provided results with accuracy within acceptable range. The utilization of HMSE in selecting drilling variables for the prediction models provided an improved and consistent methodology of predicting ROP with drilling efficiency optimization objectives. This is valuable from an operational point of view, because it provides a reference point for measuring drilling efficiency and performance of the drilling process in terms of energy input and corresponding output in terms of ROP. The real-time drilling data utilized are must-haves, easily acquired, accessible, and controllable during drilling operations.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"25 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76016237","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}
Pub Date : 2018-10-31DOI: 10.5772/INTECHOPEN.74674
Y. H. Chai, S. Yusup, V. Chok, S. Irawan
Performance issues of vegetable oil or bio-based oil drilling fluids are generally inferior as compared to synthetic based drilling fluids. This chapter focuses largely on thermal conductivity and rheological properties of bio-based oil drilling fluid as its core issues. Unstable drilling fluids do not only incur in downtime for maintenance, but it indirectly affects production capacity as well. To overcome these issues, nanoparticles acts as addi - tives to improve the thermo-physical traits of bio-based oil drilling fluid. The scope of this chapter focuses on dispersion of graphene oxide at very low concentration, namely 25, 50 and 100 ppm, to improve the thermal conductivity and rheological properties of bio-based oil drilling fluid. The data obtained from thermal conductivity and rheological experimental works were validated with various thermal conductivity and rheological models.
{"title":"Bio-Based Oil Drilling Fluid Improvements through Carbon- Based Nanoparticle Additives","authors":"Y. H. Chai, S. Yusup, V. Chok, S. Irawan","doi":"10.5772/INTECHOPEN.74674","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74674","url":null,"abstract":"Performance issues of vegetable oil or bio-based oil drilling fluids are generally inferior as compared to synthetic based drilling fluids. This chapter focuses largely on thermal conductivity and rheological properties of bio-based oil drilling fluid as its core issues. Unstable drilling fluids do not only incur in downtime for maintenance, but it indirectly affects production capacity as well. To overcome these issues, nanoparticles acts as addi - tives to improve the thermo-physical traits of bio-based oil drilling fluid. The scope of this chapter focuses on dispersion of graphene oxide at very low concentration, namely 25, 50 and 100 ppm, to improve the thermal conductivity and rheological properties of bio-based oil drilling fluid. The data obtained from thermal conductivity and rheological experimental works were validated with various thermal conductivity and rheological models.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"90 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83459458","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}
Pub Date : 2018-10-31DOI: 10.5772/INTECHOPEN.75377
G. Cavalheiro, Mariana Brandão, S. Rocha
In recent years, Brazil has emerged as a leading offshore producer with extensive proven reserves yet to be explored. As a matter of fact, the discovery of huge oil deposits in the pre-salt layer of the country’s Southeastern coast is motivating oil and gas exploration in great depths in Brazil, thereby also generating increasing demand for drilling capabilities. This study addresses the technological implications of this discovery by examining patent information. Here, we provide empirical evidence indicating an increased interest for patenting technologies designed to enhance not only ultra-deep drilling capabilities and build and maintain oil wells, but also technologies to increase oil production from formations.
{"title":"Proposing a Patent Information Approach for Identifying Technological Trends in the Brazilian Upstream Oil and Gas Industry","authors":"G. Cavalheiro, Mariana Brandão, S. Rocha","doi":"10.5772/INTECHOPEN.75377","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75377","url":null,"abstract":"In recent years, Brazil has emerged as a leading offshore producer with extensive proven reserves yet to be explored. As a matter of fact, the discovery of huge oil deposits in the pre-salt layer of the country’s Southeastern coast is motivating oil and gas exploration in great depths in Brazil, thereby also generating increasing demand for drilling capabilities. This study addresses the technological implications of this discovery by examining patent information. Here, we provide empirical evidence indicating an increased interest for patenting technologies designed to enhance not only ultra-deep drilling capabilities and build and maintain oil wells, but also technologies to increase oil production from formations.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"45 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85932075","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}
Pub Date : 2018-10-31DOI: 10.5772/INTECHOPEN.76149
S. Irawan, Imros B. Kinif
This chapter focuses on the development of solid control system that is suited for drilling 12.25-inch hole. The first part discusses the performance of rate of penetration (ROP), equivalent circulating density (ECD) and drill string drag while the second part of the chapter discusses about the effect of solid control system performance to mud properties plastic viscosity (PV), yield point (YP), and low gravity solid (LGS). The input parameters were gathered from two different set up of solid control systems that were used in Well A and Well B. The result is mainly based on the performance of original solid control system new design vs. old design. Installation of distributor tank and channeling the mud to respective shale shakers significantly enhanced the system and operational performance. The ROP at 12.25-inch drilling was improved by 20%. New design, on an average, improved the ECD margin by reducing additional pressure exerted using original mud from 4.9 to 2.9%. High ECD margin is not recommended because it can break the weak formation. Mud properties while drilling the 12.25-inch hole section; PV, YP and LGS values were improved by 14, 17, and 25% respectively.
{"title":"Solid Control System for Maximizing Drilling","authors":"S. Irawan, Imros B. Kinif","doi":"10.5772/INTECHOPEN.76149","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.76149","url":null,"abstract":"This chapter focuses on the development of solid control system that is suited for drilling 12.25-inch hole. The first part discusses the performance of rate of penetration (ROP), equivalent circulating density (ECD) and drill string drag while the second part of the chapter discusses about the effect of solid control system performance to mud properties plastic viscosity (PV), yield point (YP), and low gravity solid (LGS). The input parameters were gathered from two different set up of solid control systems that were used in Well A and Well B. The result is mainly based on the performance of original solid control system new design vs. old design. Installation of distributor tank and channeling the mud to respective shale shakers significantly enhanced the system and operational performance. The ROP at 12.25-inch drilling was improved by 20%. New design, on an average, improved the ECD margin by reducing additional pressure exerted using original mud from 4.9 to 2.9%. High ECD margin is not recommended because it can break the weak formation. Mud properties while drilling the 12.25-inch hole section; PV, YP and LGS values were improved by 14, 17, and 25% respectively.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"26 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85392362","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}
Pub Date : 2018-10-31DOI: 10.5772/INTECHOPEN.77998
P. A. Potter
In this chapter, a broad technical overview is offered to illustrate the technological advancements that have made the original direct hydraulic system reach those system design features that are shown in figure overleaf, which is a modern general arrangement of the “multiplexing” type of the BOP control system. Behind each discrete advancement, it goes without saying, there was a lot of design work, influenced by the radically differ - ent conditions in the subsea marine environment than those that we experience on land. Each step of this enabling technology is reviewed with in-depth reasoning explaining the “whys” and “wherefores” of each particular development. Let us start, as the drilling industry did for the development of BOP designs, at the beginning of the industry’s step offshore around 60 years ago. Not least, it should be emphasized that the ways in which the systems’ architecture has evolved have, in large part, been “driven” by the statutes laid out by the American Petroleum Institute (API) and later by other class societies that govern design compliance within the industry. The learning objectives of this chapter are to provide factual insights into evolving BOP control system designs as the indus try moved from onshore to offshore and subsequently from bottom-supported drilling installations to floating drilling installations. This technology also forms the basis of the underpinning principles of hydraulic/electro and multiplexing subsea control systems that are currently used in the control of all kinds of production trees, subsea production centers, subsea distribution, and pipe line end manifolds (PLEMs). This chapter can be considered as a foundation and introductory overview for the development of control systems used in the subsea environment and those engineering challenges and obstacles that have been successfully surmounted, resulting in the technology basis in use today in the manufacture of subsea control systems.
{"title":"Making the Connection for Well Control on Floaters: Evolving Design Rationales for BOP Control Systems","authors":"P. A. Potter","doi":"10.5772/INTECHOPEN.77998","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.77998","url":null,"abstract":"In this chapter, a broad technical overview is offered to illustrate the technological advancements that have made the original direct hydraulic system reach those system design features that are shown in figure overleaf, which is a modern general arrangement of the “multiplexing” type of the BOP control system. Behind each discrete advancement, it goes without saying, there was a lot of design work, influenced by the radically differ - ent conditions in the subsea marine environment than those that we experience on land. Each step of this enabling technology is reviewed with in-depth reasoning explaining the “whys” and “wherefores” of each particular development. Let us start, as the drilling industry did for the development of BOP designs, at the beginning of the industry’s step offshore around 60 years ago. Not least, it should be emphasized that the ways in which the systems’ architecture has evolved have, in large part, been “driven” by the statutes laid out by the American Petroleum Institute (API) and later by other class societies that govern design compliance within the industry. The learning objectives of this chapter are to provide factual insights into evolving BOP control system designs as the indus try moved from onshore to offshore and subsequently from bottom-supported drilling installations to floating drilling installations. This technology also forms the basis of the underpinning principles of hydraulic/electro and multiplexing subsea control systems that are currently used in the control of all kinds of production trees, subsea production centers, subsea distribution, and pipe line end manifolds (PLEMs). This chapter can be considered as a foundation and introductory overview for the development of control systems used in the subsea environment and those engineering challenges and obstacles that have been successfully surmounted, resulting in the technology basis in use today in the manufacture of subsea control systems.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"34 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80215458","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}
F. Sylvestre, M. Schuster, H. Vogel, Moussa Abdheramane, D. Arizteguí, U. Salzmann, A. Schwalb, N. Waldmann
Abstract. At present, Lake Chad (∼ 13∘′ N, ∼ 14∘ E) is a shallow freshwater lake located in the Sahel/Sahara region of central northern Africa. The lake is primarily fed by the Chari–Logone river system draining a ∼ 600 000 km2 watershed in tropical Africa. Discharge is strongly controlled by the annual passage of the intertropical convergence zone (ITCZ) and monsoon circulation leading to a peak in rainfall during boreal summer. During recent decades, a large number of studies have been carried out in the Lake Chad Basin (LCB). They have mostly focused on a patchwork of exposed lake sediments and outcrops once inhabited by early hominids. A dataset generated from a 673 m long geotechnical borehole drilled in 1973, along with outcrop and seismic reflection studies, reveal several hundred metres of Miocene–Pleistocene lacustrine deposits. CHADRILL aims to recover a sedimentary core spanning the Miocene–Pleistocene sediment succession of Lake Chad through deep drilling. This record will provide significant insights into the modulation of orbitally forced changes in northern African hydroclimate under different climate boundary conditions such as high CO2 and absence of Northern Hemisphere ice sheets. These investigations will also help unravel both the age and the origin of the lake and its current desert surrounding. The LCB is very rich in early hominid fossils (Australopithecus bahrelghazali; Sahelanthropus tchadensis) of Late Miocene age. Thus, retrieving a sediment core from this basin will provide the most continuous climatic and environmental record with which to compare hominid migrations across northern Africa and has major implications for understanding human evolution. Furthermore, due to its dramatic and episodically changing water levels and associated depositional modes, Lake Chad's sediments resemble maybe an analogue for lake systems that were once present on Mars. Consequently, the study of the subsurface biosphere contained in these sediments has the potential to shed light on microbial biodiversity present in this type of depositional environment. We propose to drill a total of ∼ 1800 m of poorly to semi-consolidated lacustrine, fluvial, and eolian sediments down to bedrock at a single on-shore site close to the shoreline of present-day Lake Chad. We propose to locate our drilling operations on-shore close to the site where the geotechnical Bol borehole (13∘28′ N, 14∘44′ E) was drilled in 1973. This is for two main reasons: (1) nowhere else in the Chad Basin do we have such detailed information about the lithologies to be drilled; and (2) the Bol site is close to the depocentre of the Chad Basin and therefore likely to provide the stratigraphically most continuous sequence.
{"title":"The Lake CHAd Deep DRILLing project (CHADRILL) – targeting ∼ 10 million years of environmental and climate change in Africa","authors":"F. Sylvestre, M. Schuster, H. Vogel, Moussa Abdheramane, D. Arizteguí, U. Salzmann, A. Schwalb, N. Waldmann","doi":"10.5194/SD-24-71-2018","DOIUrl":"https://doi.org/10.5194/SD-24-71-2018","url":null,"abstract":"Abstract. At present, Lake Chad (∼ 13∘′ N, ∼ 14∘ E) is\u0000a shallow freshwater lake located in the Sahel/Sahara region of central\u0000northern Africa. The lake is primarily fed by the Chari–Logone river system\u0000draining a ∼ 600 000 km2 watershed in tropical Africa. Discharge\u0000is strongly controlled by the annual passage of the intertropical convergence\u0000zone (ITCZ) and monsoon circulation leading to a peak in rainfall during\u0000boreal summer. During recent decades, a large number of studies have been\u0000carried out in the Lake Chad Basin (LCB). They have mostly focused on a\u0000patchwork of exposed lake sediments and outcrops once inhabited by early\u0000hominids. A dataset generated from a 673 m long geotechnical borehole\u0000drilled in 1973, along with outcrop and seismic reflection studies, reveal\u0000several hundred metres of Miocene–Pleistocene lacustrine\u0000deposits. CHADRILL aims to recover a sedimentary core spanning the Miocene–Pleistocene\u0000sediment succession of Lake Chad through deep drilling. This record will\u0000provide significant insights into the modulation of orbitally forced changes\u0000in northern African hydroclimate under different climate boundary conditions\u0000such as high CO2 and absence of Northern Hemisphere ice sheets. These\u0000investigations will also help unravel both the age and the origin of the lake\u0000and its current desert surrounding. The LCB is very rich in early hominid\u0000fossils (Australopithecus bahrelghazali; Sahelanthropus tchadensis) of Late Miocene age. Thus, retrieving a sediment core from this\u0000basin will provide the most continuous climatic and environmental record with\u0000which to compare hominid migrations across northern Africa and has major\u0000implications for understanding human evolution. Furthermore, due to its\u0000dramatic and episodically changing water levels and associated depositional\u0000modes, Lake Chad's sediments resemble maybe an analogue for lake systems that\u0000were once present on Mars. Consequently, the study of the subsurface\u0000biosphere contained in these sediments has the potential to shed light on\u0000microbial biodiversity present in this type of depositional environment. We propose to drill a total of ∼ 1800 m of poorly to semi-consolidated\u0000lacustrine, fluvial, and eolian sediments down to bedrock at a single\u0000on-shore site close to the shoreline of present-day Lake Chad. We propose to\u0000locate our drilling operations on-shore close to the site where the\u0000geotechnical Bol borehole (13∘28′ N, 14∘44′ E) was\u0000drilled in 1973. This is for two main reasons: (1) nowhere else in the Chad\u0000Basin do we have such detailed information about the lithologies to be\u0000drilled; and (2) the Bol site is close to the depocentre of the Chad Basin\u0000and therefore likely to provide the stratigraphically most continuous\u0000sequence.\u0000","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"86 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73054787","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}
P. Olsen, J. Geissman, D. Kent, G. Gehrels, R. Mundil, R. Irmis, C. Lepre, C. Rasmussen, D. Giesler, W. Parker, N. Zakharova, Wolfram M Kürschner, Charlotte S. Miller, Viktória Baranyi, M. Schaller, J. Whiteside, D. Schnurrenberger, A. Noren, K. Shannon, Ryan O’Grady, M. Colbert, J. Maisano, D. Edey, S. Kinney, R. Molina-Garza, G. H. Bachman, J. Sha
Abstract. Phase 1 of the Colorado Plateau Coring Project (CPCP-I) recovered a total of over 850 m of stratigraphically overlapping core from three coreholes at two sites in the Early to Middle and Late Triassic age largely fluvial Moenkopi and Chinle formations in Petrified Forest National Park (PFNP), northeastern Arizona, USA. Coring took place during November and December of 2013 and the project is now in its post-drilling science phase. The CPCP cores have abundant detrital zircon-producing layers (with survey LA-ICP-MS dates selectively resampled for CA-ID-TIMS U-Pb ages ranging in age from at least 210 to 241 Ma), which together with their magnetic polarity stratigraphy demonstrate that a globally exportable timescale can be produced from these continental sequences and in the process show that a prominent gap in the calibrated Phanerozoic record can be filled. The portion of core CPCP-PFNP13-1A for which the polarity stratigraphy has been completed thus far spans ∼215 to 209 Ma of the Late Triassic age, and strongly validates the longer Newark-Hartford Astrochronostratigraphic-calibrated magnetic Polarity Time-Scale (APTS) based on cores recovered in the 1990s during the Newark Basin Coring Project (NBCP). Core recovery was ∼100 % in all holes (Table 1). The coreholes were inclined ∼60–75∘ approximately to the south to ensure azimuthal orientation in the nearly flat-lying bedding, critical to the interpretation of paleomagentic polarity stratigraphy. The two longest of the cores (CPCP-PFNP13-1A and 2B) were CT-scanned in their entirety at the University of Texas High Resolution X-ray CT Facility in Austin, TX, and subsequently along with 2A, all cores were split and processed at the CSDCO/LacCore Facility, in Minneapolis, MN, where they were scanned for physical property logs and imaging. While remaining the property of the Federal Government, the archive half of each core is curated at the NSF-sponsored LacCore Core Repository and the working half is stored at the Rutgers University Core Repository in Piscataway, NJ, where the initial sampling party was held in 2015 with several additional sampling events following. Additional planned study will recover the rest of the polarity stratigraphy of the cores as additional zircon ages, sedimentary structure and paleosol facies analysis, stable isotope geochemistry, and calibrated XRF core scanning are accomplished. Together with strategic outcrop studies in Petrified Forest National Park and environs, these cores will allow the vast amount of surface paleontological and paleoenvironmental information recorded in the continental Triassic of western North America to be confidently placed in a secure context along with important events such as the giant Manicouagan impact at ∼215.5 Ma (Ramezani et al., 2005) and long wavelength astronomical cycles pacing global environmental change and trends in atmospheric gas composition during the dawn of the dinosaurs.
{"title":"Colorado Plateau Coring Project, Phase I (CPCP-I): a continuously cored, globally exportable chronology of Triassic continental environmental change from western North America","authors":"P. Olsen, J. Geissman, D. Kent, G. Gehrels, R. Mundil, R. Irmis, C. Lepre, C. Rasmussen, D. Giesler, W. Parker, N. Zakharova, Wolfram M Kürschner, Charlotte S. Miller, Viktória Baranyi, M. Schaller, J. Whiteside, D. Schnurrenberger, A. Noren, K. Shannon, Ryan O’Grady, M. Colbert, J. Maisano, D. Edey, S. Kinney, R. Molina-Garza, G. H. Bachman, J. Sha","doi":"10.5194/SD-24-15-2018","DOIUrl":"https://doi.org/10.5194/SD-24-15-2018","url":null,"abstract":"Abstract. Phase 1 of the Colorado Plateau Coring Project (CPCP-I) recovered a total of over 850 m of stratigraphically overlapping core from three coreholes at two sites in the Early to Middle and Late Triassic age largely fluvial Moenkopi and Chinle formations in Petrified Forest National Park (PFNP), northeastern Arizona, USA. Coring took place during November and December of 2013 and the project is now in its post-drilling science phase. The CPCP cores have abundant detrital zircon-producing layers (with survey LA-ICP-MS dates selectively resampled for CA-ID-TIMS U-Pb ages ranging in age from at least 210 to 241 Ma), which together with their magnetic polarity stratigraphy demonstrate that a globally exportable timescale can be produced from these continental sequences and in the process show that a prominent gap in the calibrated Phanerozoic record can be filled. The portion of core CPCP-PFNP13-1A for which the polarity stratigraphy has been completed thus far spans ∼215 to 209 Ma of the Late Triassic age, and strongly validates the longer Newark-Hartford Astrochronostratigraphic-calibrated magnetic Polarity Time-Scale (APTS) based on cores recovered in the 1990s during the Newark Basin Coring Project (NBCP). Core recovery was ∼100 % in all holes (Table 1). The coreholes were inclined ∼60–75∘ approximately to the south to ensure azimuthal orientation in the nearly flat-lying bedding, critical to the interpretation of paleomagentic polarity stratigraphy. The two longest of the cores (CPCP-PFNP13-1A and 2B) were CT-scanned in their entirety at the University of Texas High Resolution X-ray CT Facility in Austin, TX, and subsequently along with 2A, all cores were split and processed at the CSDCO/LacCore Facility, in Minneapolis, MN, where they were scanned for physical property logs and imaging. While remaining the property of the Federal Government, the archive half of each core is curated at the NSF-sponsored LacCore Core Repository and the working half is stored at the Rutgers University Core Repository in Piscataway, NJ, where the initial sampling party was held in 2015 with several additional sampling events following. Additional planned study will recover the rest of the polarity stratigraphy of the cores as additional zircon ages, sedimentary structure and paleosol facies analysis, stable isotope geochemistry, and calibrated XRF core scanning are accomplished. Together with strategic outcrop studies in Petrified Forest National Park and environs, these cores will allow the vast amount of surface paleontological and paleoenvironmental information recorded in the continental Triassic of western North America to be confidently placed in a secure context along with important events such as the giant Manicouagan impact at ∼215.5 Ma (Ramezani et al., 2005) and long wavelength astronomical cycles pacing global environmental change and trends in atmospheric gas composition during the dawn of the dinosaurs.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"18 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76358382","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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