Search results for "drilling"
showing 10 items of 88 documents
Intraosseous monitoring of drilling in lumbar vertebrae by ultrasound: An experimental feasibility study.
2016
The rationale for this project is to evaluate the efficiency of a novel sonographic method for measurements of interosseous distances. The method utilizes a propagating ultrasonic beam through aqueous milieu which is directed as a jet into a drilled tract. We used a plastic model of human L5 vertebra and ex vivo specimen of L5 porcine vertebra and generated 2 mm in diameter tracts in vertebral pedicles. The tracts were created in the "desired" central direction and in the "wrong" medial and lateral directions. The drilled tracts and the residual, up to opposite cortex, distances were measured sonographically and mechanically and compared statistically. We show that "true" mechanical measure…
Investigating the effect of residual stress on hydrogen cracking in multi-pass robotic welding through process compatible non-destructive testing
2021
Abstract In this paper, the effect of Welding Residual Stress (WRS) on the size and morphology of hydrogen-induced cracks (HIC) is studied. Four samples were manufactured using a 6-axis welding robot and in two separate batches. The difference between the two batches was the clamping system used, which resulted in different amounts of welding deformation and WRS. The hydrogen cracks were intentionally manufactured in the samples using a localised water-quenching method, where water was sprayed over a specific weld pass in a predetermined position. The Phased-Array Ultrasonic Testing (PAUT) system was implemented during the welding process (high-temperature in-process method), to detect the …
Identifying sedimentary structures and spatial distribution of tsunami deposits with GPR - examples from Spain and Greece
2011
Shallow drilling in coastal areas like southern Spain and different parts of Greece (Corinth region and Argolis Gulf) proved evidence for tsunamis. Sedimentary analyses were conducted to identify tsunamigenic deposits, but did not reveal sedimentary structures or spatial distribution of tsunamites in a regional scale. Since drilling is time-intensive and expensive (depending on extend), this method can by far not cover an entire coastal area. On the other hand, distribution and preservation of tsunamigenic deposits seems to be highly variable. We used ground penetrating radar (GPR) in combination with electrical resistivity tomography (ERT) measurements and sedimentological research methods…
Considerations on sand control in natural gas wells
2017
Mechanism of sand production in gas wells is complex and influenced by every operation performed into the well, starting from the opening of the production interval by drilling, and continuing with completion and putting into production as well as with the exploitation regime. Sand production along with fluids from gas reservoirs creates a series of potentially dangerous and costly problems. For selecting the most appropriate methods of sand-control all the data and information related to properties of reservoir rock, the history of sand production, the potential well flow rates as well as HSE and costs need to be evaluated. The conclusion of the authors is that the best results in sand con…
A Recent Advancement: Casing while Drilling – A Viable Alternative to Conventional Drilling
2021
Mankind’s increased requirement for and dependence on energy resources, including the resources resulting from discovery and development of new hydrocarbon commercial reservoirs involves the use of new technologies such as optimization of the drilling process by reducing the non-productive time, the costs and the risks. Casing while drilling involves elimination of classical drilling string by using the casing string both for transmission to the bit of the mechanical energy and for circulation of drilling fluid into the well. Casing while drilling, constantly improving over time, has proven an efficient method to reduce risks, especially those related to the presence of a conventional…
Casing while Drilling – a Viable Alternative to Conventional Drilling
2019
Mankind’s increased requirement for and dependence on energy resources, including the resources resulting from discovery and development of new hydrocarbon commercial reservoirs involves the use of new technologies such as optimization of the drilling process by reducing the non-productive time, the costs and the risks. Casing while drilling involves elimination of classical drilling string by using the casing string both for transmission to the bit of the mechanical energy and for circulation of drilling fluid into the well. Although there is a number of technical or perception barriers related to the use of casing drilling, the important benefits of this technology related to reduced dril…
Dependence between aging treatments and residual stresses on composite laminate
2006
International audience; The objective of this paper is to study the influence of residual stresses due to fabrication conditions on the thermomechanical behavior of carbon/epoxy laminate structures (cross ply). These studied laminates have undergone various cycles of thermal aging. The addition of a post-cure cycle after the end of the initial cycle makes it possible to reduce the residual stresses level. The incremental hole-drilling method is used to measure the residual strain in the laminates. These measured strains and the numerical calibration coefficients obtained by the finite element method allow to calculating the residual stress distribution in composite depth. The obtained resul…
Optimization of depth increment distribution in the ring-core method
1996
The integral equation method is the most suitable calculation procedure for the determination of non-uniform residual stresses by semi-destructive mechanical methods such as hole and ring-core drilling. However, the high sensitivity to strain measurement errors due to the ill-conditioning of the equation sets has prevented its practical use. Examination of the influence of the strain measurement error on the calculated stresses and its propagation has shown that, for given maximum groove depth and total steps number, the error sensitivity depends on the particular depth increment distribution used. By means of an alternative matrix formulation of the equation sets the depth increment distr…
Perforazione della Caldera dei Campi Flegrei - Una proposta anfibia IODP-ICDP
2018
Active calderas are major volcanic features of the Earth’s crust associated with shallow magma reservoirs, high geothermal gradients, and geodynamic unrests often documented through historical time. As large caldera-forming eruptions are also among the most catastrophic events that may affect the Earth’s surface, calderas are ostensibly the sites of major interest for both the scientific community and governmental institutions worldwide. The Campi Flegrei is an active volcanic area located west of the city of Naples, largely on the continental shelf of the Eastern Tyrrhenian margin that has been characterized by dominantly explosive eruptions during the latest Quaternary. This is one among …
1D Compression Behaviour of Opalinus Clay
2017
One of the main concerns related to tunnel excavations, drilling operations and wellbore stability in shales is the generation of excess pore water pressure due to changes in mechanical stress; therefore the consolidation of shales is a fundamental process that must be considered. This paper presents a compre- hensive methodology for analysing the compression and consolidation behaviour of shales. An apparatus to perform high-pressure oedometric tests is presented and an analytical method is introduced to analyse the shale consolidation behaviour, which allows information to be gathered on the coeffi cient of consolidation, stiffness, poroelastic properties, and permeability of the tested m…