The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Chiara Bosco - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the Theoretical Net Relief Drilling Rate for Conductor Pipes
Geotechnical and Geological Engineering, 2017Co-Authors: Giovanni Spagnoli, Alistair Kirby, Paul Adams, Pierpaolo Oreste, Chiara BoscoAbstract:The following paper deals with the prediction of the theoretical net Drilling time for a conductor pipe (CP) of offshore platforms when it plugs. The CP is driven to prevent the looser surface layer from caving in and obstructing the wellbore, because the shallow section of most wells on- and offshore is drilled in unconsolidated sediment. Due to the small CP diameter, the CP plugs very often. Normally the material is drilled out by using jetting, normal drill rigs and sometimes jack-up rigs. As offshore operations time is very important, this paper tries to assess the theoretical net time needed to excavate within the CP as a relief Drilling operation, by means of Nishimatsu and Evans cutting theories. The results are compared with publicly available TBM excavation Rates and then theoretical Drilling Rates for different unconfined compressive strength values for CP diameters of 700, 900 and 1000 mm are suggested. The results are considered for drag bits, however, they are only theoretical assumptions and cannot be applied for commercial projects with the same geotechnical properties.
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a probabilistic approach for estimating the theoretical net Drilling Rate for offshore bored piles
Geotechnique Letters, 2016Co-Authors: Chiara Bosco, Giovanni Spagnoli, Pierpaolo OresteAbstract:Driven piles, installed by using hammers, are the most common offshore foundation type. However, in certain cases driven piles can incur in a premature refusal (due to plug formations, hard layers, presences of rock and boulders or soil set-up). Drilled piles are therefore used as a back-up solution. However, the technology is not always preferred as time is a key factor for offshore operations and a pile drillability analysis is generally more complex and less reliable than a drivability assessment. This paper extends the results of previous researches, which considered a theoretical Drilling Rate model based on the estimation of the specific excavation energy, applying a probabilistic approach. To consider the uncertainty of the geotechnical parameters of soil/rock used in Drilling pile projects, a statistical method – that is, the Monte-Carlo method, has been applied to two cases of weak rock/cemented soil. It was possible to obtain the theoretical Drilling Rate values as a probabilistic distribution i...
Giovanni Spagnoli - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the Theoretical Net Relief Drilling Rate for Conductor Pipes
Geotechnical and Geological Engineering, 2017Co-Authors: Giovanni Spagnoli, Alistair Kirby, Paul Adams, Pierpaolo Oreste, Chiara BoscoAbstract:The following paper deals with the prediction of the theoretical net Drilling time for a conductor pipe (CP) of offshore platforms when it plugs. The CP is driven to prevent the looser surface layer from caving in and obstructing the wellbore, because the shallow section of most wells on- and offshore is drilled in unconsolidated sediment. Due to the small CP diameter, the CP plugs very often. Normally the material is drilled out by using jetting, normal drill rigs and sometimes jack-up rigs. As offshore operations time is very important, this paper tries to assess the theoretical net time needed to excavate within the CP as a relief Drilling operation, by means of Nishimatsu and Evans cutting theories. The results are compared with publicly available TBM excavation Rates and then theoretical Drilling Rates for different unconfined compressive strength values for CP diameters of 700, 900 and 1000 mm are suggested. The results are considered for drag bits, however, they are only theoretical assumptions and cannot be applied for commercial projects with the same geotechnical properties.
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a probabilistic approach for estimating the theoretical net Drilling Rate for offshore bored piles
Geotechnique Letters, 2016Co-Authors: Chiara Bosco, Giovanni Spagnoli, Pierpaolo OresteAbstract:Driven piles, installed by using hammers, are the most common offshore foundation type. However, in certain cases driven piles can incur in a premature refusal (due to plug formations, hard layers, presences of rock and boulders or soil set-up). Drilled piles are therefore used as a back-up solution. However, the technology is not always preferred as time is a key factor for offshore operations and a pile drillability analysis is generally more complex and less reliable than a drivability assessment. This paper extends the results of previous researches, which considered a theoretical Drilling Rate model based on the estimation of the specific excavation energy, applying a probabilistic approach. To consider the uncertainty of the geotechnical parameters of soil/rock used in Drilling pile projects, a statistical method – that is, the Monte-Carlo method, has been applied to two cases of weak rock/cemented soil. It was possible to obtain the theoretical Drilling Rate values as a probabilistic distribution i...
Pierpaolo Oreste - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the Theoretical Net Relief Drilling Rate for Conductor Pipes
Geotechnical and Geological Engineering, 2017Co-Authors: Giovanni Spagnoli, Alistair Kirby, Paul Adams, Pierpaolo Oreste, Chiara BoscoAbstract:The following paper deals with the prediction of the theoretical net Drilling time for a conductor pipe (CP) of offshore platforms when it plugs. The CP is driven to prevent the looser surface layer from caving in and obstructing the wellbore, because the shallow section of most wells on- and offshore is drilled in unconsolidated sediment. Due to the small CP diameter, the CP plugs very often. Normally the material is drilled out by using jetting, normal drill rigs and sometimes jack-up rigs. As offshore operations time is very important, this paper tries to assess the theoretical net time needed to excavate within the CP as a relief Drilling operation, by means of Nishimatsu and Evans cutting theories. The results are compared with publicly available TBM excavation Rates and then theoretical Drilling Rates for different unconfined compressive strength values for CP diameters of 700, 900 and 1000 mm are suggested. The results are considered for drag bits, however, they are only theoretical assumptions and cannot be applied for commercial projects with the same geotechnical properties.
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a probabilistic approach for estimating the theoretical net Drilling Rate for offshore bored piles
Geotechnique Letters, 2016Co-Authors: Chiara Bosco, Giovanni Spagnoli, Pierpaolo OresteAbstract:Driven piles, installed by using hammers, are the most common offshore foundation type. However, in certain cases driven piles can incur in a premature refusal (due to plug formations, hard layers, presences of rock and boulders or soil set-up). Drilled piles are therefore used as a back-up solution. However, the technology is not always preferred as time is a key factor for offshore operations and a pile drillability analysis is generally more complex and less reliable than a drivability assessment. This paper extends the results of previous researches, which considered a theoretical Drilling Rate model based on the estimation of the specific excavation energy, applying a probabilistic approach. To consider the uncertainty of the geotechnical parameters of soil/rock used in Drilling pile projects, a statistical method – that is, the Monte-Carlo method, has been applied to two cases of weak rock/cemented soil. It was possible to obtain the theoretical Drilling Rate values as a probabilistic distribution i...
Hamid Reza Ansari - One of the best experts on this subject based on the ideXlab platform.
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Drilling Rate of penetration prediction through committee support vector regression based on imperialist competitive algorithm
Carbonates and Evaporites, 2017Co-Authors: Hamid Reza Ansari, Mohammad Javad Sarbaz Hosseini, Masoud AmirpourAbstract:Rate of penetration (ROP) is an important parameter affecting the Drilling optimization during well planning. This is particularly important for offshore wells because, offshore rigs contain daily expensive cost and therefore ROP plays a critical role in minimizing time and cost of Drilling. There are many factors that affect the ROP such as mud, formation, bit and Drilling parameters. In the first step of this study, the best parameters to predict ROP, are selected by error analysis of multivariate regression and then ROP modeling is performed by means of various support vector regression (SVR) methods. Fundamental difference between the individual models is type of kernel function. Finally, a committee machine is constructed in power law framework and it is optimized with imperialist competitive algorithm (ICA). This novel technique is called committee support vector regression based on imperialist competitive algorithm (CSVR-ICA) in this study. Data set are gathered from three jack-up Drilling rigs. Results show that CSVR-ICA model improved the results of individual SVR models and it has a good performance in the ROP estimation.
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Optimized support vector regression for Drilling Rate of penetration estimation
Open Geosciences, 2015Co-Authors: Asadollah Bodaghi, Hamid Reza Ansari, Mahsa GholamiAbstract:Abstract In the petroleum industry, Drilling optimization involves the selection of operating conditions for achieving the desired depth with the minimum expenditure while requirements of personal safety, environment protection, adequate information of penetRated formations and productivity are fulfilled. Since Drilling optimization is highly dependent on the Rate of penetration (ROP), estimation of this parameter is of great importance during well planning. In this research, a novel approach called ‘optimized support vector regression’ is employed for making a formulation between input variables and ROP. Algorithms used for optimizing the support vector regression are the genetic algorithm (GA) and the cuckoo search algorithm (CS). Optimization implementation improved the support vector regression performance by virtue of selecting proper values for its parameters. In order to evaluate the ability of optimization algorithms in enhancing SVR performance, their results were compared to the hybrid of pattern search and grid search (HPG) which is conventionally employed for optimizing SVR. The results demonstRated that the CS algorithm achieved further improvement on prediction accuracy of SVR compared to the GA and HPG as well. Moreover, the predictive model derived from back propagation neural network (BPNN), which is the traditional approach for estimating ROP, is selected for comparisons with CSSVR. The comparative results revealed the superiority of CSSVR. This study inferred that CSSVR is a viable option for precise estimation of ROP.
Isamu Miyamoto - One of the best experts on this subject based on the ideXlab platform.
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High speed Drilling of thin silicon wafer by UV laser
International Congress on Applications of Lasers & Electro-Optics, 2020Co-Authors: Isamu Miyamoto, Shinsuke Asada, Tomokazu Sano, Etsuji OhmuraAbstract:Drilling Rate of thin silicon wafer of 50µm was investigated as a function of diameter and fluence by using KrF excimer laser. The Drilling Rate at constant fluence increases rapidly with decreasing beam diameter below 20µm, reaching approximately up to 4µm/pulse at diameter of 7µm. Melt ejection is the predominant mechanism in Drilling at beam diameters less than 30µm, and approximately 60% of laser energy remains in the silicon wafer. A simple formula giving Drilling Rate was derived as a function of diameter and fluence of laser beam, and agreed well with the experimental values in a wide range of diameter and fluence. Drilling Rate of 7milion holes/s of 10µm in diameter for 50µm thick silicon wafer are estimated at laser power of 100W.Drilling Rate of thin silicon wafer of 50µm was investigated as a function of diameter and fluence by using KrF excimer laser. The Drilling Rate at constant fluence increases rapidly with decreasing beam diameter below 20µm, reaching approximately up to 4µm/pulse at diameter of 7µm. Melt ejection is the predominant mechanism in Drilling at beam diameters less than 30µm, and approximately 60% of laser energy remains in the silicon wafer. A simple formula giving Drilling Rate was derived as a function of diameter and fluence of laser beam, and agreed well with the experimental values in a wide range of diameter and fluence. Drilling Rate of 7milion holes/s of 10µm in diameter for 50µm thick silicon wafer are estimated at laser power of 100W.
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High-efficiency microDrilling of silicon wafer using excimer laser
First International Symposium on Laser Precision Microfabrication, 2000Co-Authors: Shinsuke Asada, Tomokazu Sano, Isamu MiyamotoAbstract:Drilling Rate of thin silicon wafer of 50(mu) thickness was determined as a function of beam diameter and laser fluence of KrF excimer laser with a pulse width of approximately 30ns FMHW. Analysis of Drilling process indicated that decreasing beam diameter and laser fluence enhanced the Drilling Rate with improved quality of the drilled hole. The extent of debris and molten particles ejected from the hole was also reduced as the laser fluence was decreased. The Drilling Rate, approximately 0.6(mu) per pulse at beam diameters larger than 100(mu) , increased significantly as the beam diameter decreased especially below 20(mu) , reaching approximately as large as 4(mu) per pulse at 10(mu) in diameter under constant laser fluence. On the other hand, only very small increase in Drilling Rate was observed as the laser fluence was increased. A simple formula was derived where the Drilling Rate is proportional to the fourth root of the laser fluence and inversely proportional to the square root of the beam diameter, assuming that the silicon is removed in a liquid state out of the hole.
