scholarly journals Subsurface Thermal Modeling of Oxia Planum, Landing Site of ExoMars 2022

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
M. Formisano ◽  
M. C. De Sanctis ◽  
C. Federico ◽  
G. Magni ◽  
F. Altieri ◽  
...  
Keyword(s):  
Thermal Inertia ◽  
Landing Site ◽  
Lateral Wall ◽  
Water Ice ◽  
Self Heating ◽  
Drilling Operations ◽  
Drilling System ◽  
Frictional Coefficients ◽  
Heat Released ◽  
Multispectral Imager

Numerical simulations are required to thermophysically characterize Oxia Planum, the landing site of the mission ExoMars 2022. A drilling system is installed on the ExoMars rover, and it will be able to analyze down to 2 meters in the subsurface of Mars. The spectrometer Ma_MISS (Mars Multispectral Imager for Subsurface, Coradini and Da Pieve, 2001) will investigate the lateral wall of the borehole generated by the drill, providing hyperspectral images. It is not fully clear if water ice can be found in the subsurface at Oxia Planum. However, Ma_MISS has the capability to characterize and map the presence of possible ices, in particular water ice. We performed simulations of the subsurface temperatures by varying the thermal inertia, and we quantified the effects of self-heating. Moreover, we quantified the heat released by the drilling operations, by exploring different frictional coefficients and angular drill velocities, in order to evaluate the lifetime of possible water ice.

scholarly journals Autonomous Decision-Making While Drilling

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 969
Author(s):  
Eric Cayeux ◽  
Benoît Daireaux ◽  
Adrian Ambrus ◽  
Rodica Mihai ◽  
Liv Carlsen
Keyword(s):  
Decision Making ◽  
Internal State ◽  
Drilling Process ◽  
Autonomous Decision ◽  
Internal States ◽  
Markov Decision ◽  
Drilling Operations ◽  
Drilling System ◽  
Drilling Conditions ◽  
Erratic Behavior

The drilling process is complex because unexpected situations may occur at any time. Furthermore, the drilling system is extremely long and slender, therefore prone to vibrations and often being dominated by long transient periods. Adding the fact that measurements are not well distributed along the drilling system, with the majority of real-time measurements only available at the top side and having only access to very sparse data from downhole, the drilling process is poorly observed therefore making it difficult to use standard control methods. Therefore, to achieve completely autonomous drilling operations, it is necessary to utilize a method that is capable of estimating the internal state of the drilling system from parsimonious information while being able to make decisions that will keep the operation safe but effective. A solution enabling autonomous decision-making while drilling has been developed. It relies on an optimization of the time to reach the section total depth (TD). The estimated time to reach the section TD is decomposed into the effective time spent in conducting the drilling operation and the likely time lost to solve unexpected drilling events. This optimization problem is solved by using a Markov decision process method. Several example scenarios have been run in a virtual rig environment to test the validity of the concept. It is found that the system is capable to adapt itself to various drilling conditions, as for example being aggressive when the operation runs smoothly and the estimated uncertainty of the internal states is low, but also more cautious when the downhole drilling conditions deteriorate or when observations tend to indicate more erratic behavior, which is often observed prior to a drilling event.

scholarly journals Spectrophotometric characterization of the Philae landing site and surroundings with the Rosetta/OSIRIS cameras

2020 ◽  
Vol 498 (1) ◽  
pp. 1221-1238
Author(s):  
Hong Van Hoang ◽  
S Fornasier ◽  
E Quirico ◽  
P H Hasselmann ◽  
M A Barucci ◽  
...  
Keyword(s):  
Total Mass ◽  
Morphological Changes ◽  
Landing Site ◽  
Spectral Slope ◽  
Water Ice ◽  
Total Mass Loss ◽  
Before And After ◽  
Comet 67P ◽  
Cometary Activity

ABSTRACT We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov–Gerasimenko on 2014 November 12. Over 1000 OSIRIS-level 3B images were analysed, which cover the 2014 August–2016 September timeframe, with spatial resolution ranging from 7.6 m pixel−1 to approximately 0.06 m pixel−1. We found that the Abydos site is as dark as the global 67P nucleus and spectrally red, with an average albedo of 6.5 per cent at 649 nm and a spectral slope value of about 17 per cent/(100 nm) at 50° phase angle. Similar to the whole nucleus, the Abydos site also shows phase reddening but with lower coefficients than other regions of the comet, which may imply a thinner cover of microscopically rough regolith compared to other areas. Seasonal variations, as already noticed for the whole nucleus, were also observed. We identified some potential morphological changes near the landing site implying a total mass-loss of (4.7–7.0) × 105 kg. Small spots ranging from 0.1 to 27 m2 were observed close to Abydos before and after perihelion. Their estimated water ice abundance reaches 30–40 per cent locally, indicating fresh exposures of volatiles. Their lifetime ranges from a few hours up to three months for two pre-perihelion spots. The Abydos surroundings showed a low level of cometary activity compared to other regions of the nucleus. Only a few jets are reported originating nearby Abydos, including a bright outburst that lasted for about 1 h.

Study of Nonlinear Internal Waves and Impact on Offshore Drilling Units

2011 ◽  
Author(s):  
Nishu V. Kurup ◽  
Shan Shi ◽  
Zhongmin Shi ◽  
Wenju Miao ◽  
Lei Jiang
Keyword(s):  
Numerical Model ◽  
South China Sea ◽  
Internal Wave ◽  
Internal Waves ◽  
South China ◽  
Andaman Sea ◽  
Offshore Drilling ◽  
Nonlinear Internal Waves ◽  
Drilling Operations ◽  
Drilling System

Internal waves near the ocean surface have been observed in many parts of the world including the Andaman Sea, Sulu Sea and South China Sea among others. The factors that cause and propagate these large amplitude waves include bathymetry, density stratification and ocean currents. Although their effects on floating drilling platforms and its riser systems have not been extensively studied, these waves have in the past seriously disrupted offshore exploration and drilling operations. In particular a drill pipe was ripped from the BOP and lost during drilling operations in the Andaman sea. Drilling riser damages were also reported from the south China Sea among other places. The purpose of this paper is to present a valid numerical model conforming to the physics of weakly nonlinear internal waves and to study the effects on offshore drilling semisubmersibles and riser systems. The pertinent differential equation that captures the physics is the Korteweg-de Vries (KdV) equation which has a general solution involving Jacobian elliptical functions. The solution of the Taylor Goldstein equation captures the effects of the pycnocline. Internal wave packets with decayed oscillations as observed from satellite pictures are specifically modeled. The nonlinear internal waves are characterized by wave amplitudes that can exceed 50 ms and the present of shearing currents near the layer of pycnocline. The offshore drilling system is exposed to these current shears and the associated movements of large volumes of water. The effect of internal waves on drilling systems is studied through nonlinear fully coupled time domain analysis. The numerical model is implemented in a coupled analysis program where the hull, moorings and riser are considered as an integrated system. The program is then utilized to study the effects of the internal wave on the platform global motions and drilling system integrity. The study could be useful for future guidance on offshore exploration and drilling operations in areas where the internal wave phenomenon is prominent.

Thermal Physics of Cometary Nuclei

2020 ◽  
Author(s):  
Dina Prialnik
Keyword(s):  
Solar Energy ◽  
Thermal Emission ◽  
Thermal Evolution ◽  
Internal Heat ◽  
Thermal Inertia ◽  
Skin Depth ◽  
Physical Models ◽  
The Sun ◽  
Cometary Nuclei ◽  
Water Ice

Cometary nuclei, as small, spinning, ice-rich objects revolving around the sun in eccentric orbits, are powered and activated by solar radiation. Far from the sun, most of the solar energy is reradiated as thermal emission, whereas close to the sun, it is absorbed by sublimation of ice. Only a small fraction of the solar energy is conducted into the nucleus interior. The rate of heat conduction determines how deep and how fast this energy is dissipated. The conductivity of cometary nuclei, which depends on their composition and porosity, is estimated based on vastly different models ranging from very simple to extremely complex. The characteristic response to heating is determined by the skin depth, the thermal inertia, and the thermal diffusion timescale, which depend on the comet’s structure and dynamics. Internal heat sources include the temperature-dependent crystallization of amorphous water ice, which becomes important at temperatures above about 130 K; occurs in spurts; and releases volatiles trapped in the ice. These, in turn, contribute to heat transfer by advection and by phase transitions. Radiogenic heating resulting from the decay of short-lived unstable nuclei such as 26Al heats the nucleus shortly after formation and may lead to compositional alterations. The thermal evolution of the nucleus is described by thermo-physical models that solve mass and energy conservation equations in various geometries, sometimes very complicated, taking into account self-heating. Solutions are compared with actual measurements from spacecraft, mainly during the Rosetta mission, to deduce the thermal properties of the nucleus and decipher its activity pattern.

Water-Ice Cloud Thermal Effects at the Phoenix Mission Landing Site 

2021 ◽  
Author(s):  
Grace Bischof ◽  
Brittney Cooper ◽  
John E. Moores
Keyword(s):  
Thermal Effects ◽  
Landing Site ◽  
Water Ice ◽  
Ice Cloud ◽  
Phoenix Mission ◽  
The Phoenix

The 3.1 μm absorption feature on asteroids (24) Themis and (65) Cybele is not due to surface water ice

2021 ◽  
Author(s):  
Laurence O'Rourke ◽  
Thomas G. Müller ◽  
Nicolas Biver ◽  
Dominique Bockelée-Morvan ◽  
Sunao Hasegawa ◽  
...  
Keyword(s):  
Surface Water ◽  
Line Emission ◽  
Thermal Inertia ◽  
Infrared Camera ◽  
Far Infrared ◽  
Subsurface Water ◽  
Absorption Feature ◽  
Water Ice ◽  
V Band ◽  
Thermophysical Model

<p>Previous research on Asteroids (24) Themis and (65) Cybele have shown the presence of an absorption feature at 3.1 μm reported to be directly linked to surface water ice. We searched for water vapor escaping from these asteroids with the Herschel Space Observatory HIFI (Heterodyne Instrument for the Far Infrared) Instrument. While no H<sub>2</sub>O line emission was detected, we obtained sensitive 3σ water production rate upper limits of Q(H<sub>2</sub>O)< 4.1×10<sup>26</sup> molecules s<sup>−1</sup> for Themis and Q(H<sub>2</sub>O) <7.6 × 10<sup>26</sup> molecules s<sup>−1</sup> for the case of Cybele. Using a thermophysical model, we merged data from the Subaru/Cooled Mid-Infrared Camera and Spectrometer and the Herschel SPIRE (Spectral and Photometric Imaging Receiver) instrument with the contents of a multi-observatory database and thus derived new radiometric properties for these two asteroids. For Themis, we obtained a thermal inertia G = 20 <sup>+25</sup><sub>-10</sub> J m<sup>−2</sup> s<sup>−1/2</sup> K<sup>−1</sup>, a diameter 192 <sup>+10</sup><sub>-7</sub> km, and a geometric V-band albedo p<sub>V</sub>=0.07±0.01. For Cybele, we found a thermal inertia G = 25<sup>+28</sup><sub>-19</sub> J m<sup>−2</sup> s<sup>−1/2</sup> K<sup>−1</sup>, a diameter 282±9 km, and an albedo pV=0.042±0.005. Using all inputs, we estimated that water ice intimately mixed with the asteroids’ dark surface material would cover <0.0017% (for Themis) and <0.0033% (for Cybele) of their surfaces, while an areal mixture with very clean ice (Bond albedo 0.8 for Themis and 0.7 for Cybele) would cover <2.2% (for Themis) and <1.5% (for Cybele) of their surfaces. Based on these very low percentage coverage values, it is clear that while surface (and subsurface) water ice may exist in small localized amounts on both asteroids, it is not the reason for the observed 3.1 μm absorption feature.</p>

Riser gas risk mitigation with advanced flow detection and managed pressure drilling technologies in deepwater operations in Australia

2014 ◽  
Vol 54 (1) ◽  
pp. 23
Author(s):  
Julmar Shaun Sadicon Toralde ◽  
Chad Henry Wuest ◽  
Robert DeGasperis
Keyword(s):  
Risk Mitigation ◽  
Control Device ◽  
Asia Pacific ◽  
Well Control ◽  
Alternative Approach ◽  
Managed Pressure Drilling ◽  
Drilling Operations ◽  
Drilling System ◽  
Flow Detection ◽  
And Control

The threat of riser gas in deepwater drilling operations is real. Studies show that gas kicks unintentionally entrained in oil-based mud in deepwater are unlikely to break out of solution until they are above the subsea blowout preventers (BOPs). The rig diverter is conventionally used to vent riser gas with minimal control and considerable risk and environmental impact involved. Reactive riser gas systems provide a riser gas handling (RGH) joint that is composed of a retrofitted annular BOP and a flow spool with hoses installed on top of the rig marine riser. A proactive, alternative approach to riser gas handling, called riser gas risk mitigation, is proposed by using managed pressure drilling (MPD) equipment. MPD involves the use of a rotating control device (RCD) to create a closed and pressurisable drilling system where flow out of the well is diverted to an automated MPD choke manifold with a high-resolution mass flow meter that increases the sensitivity and reaction time of the system to kicks, losses and other unwanted drilling events. Experiments and field deployments have shown that the deepwater MPD system can detect a gas influx before it dissolves in oil-based mud, allowing for management of the same using conventional well control methods. Since the MPD system has already closed the well in, automatic diversion and control of gas in the riser is also possible, if required. This paper presents experience gained from deepwater MPD operations in the Asia-Pacific to illustrate this, and possible deployment options in Australia are discussed.

Optimizing Saudi Aramco Reentry Drilling Operations with the First Worldwide Combined High Dogleg RSS and Underreaming Drilling System

2014 ◽  
Author(s):  
Rami Saleh ◽  
Noor Chozin Ali ◽  
Yousif Abuahmad ◽  
Naser Otaibi ◽  
Ahmed Osman ◽  
...  
Keyword(s):  
Saudi Aramco ◽  
Drilling Operations ◽  
Drilling System

scholarly journals An Outlook of Drilling Technologies and Innovations: Present Status and Future Trends

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4499
Author(s):  
Catalin Teodoriu ◽  
Opeyemi Bello
Keyword(s):  
Oil And Gas ◽  
Academic Research ◽  
Cost Effective ◽  
Operational Performance ◽  
Great Effort ◽  
Technological Advancement ◽  
The Past ◽  
Drilling Operations ◽  
Drilling System ◽  
Selection Of

The present article analyzes the technological advancement and innovations related to drilling operations. It covers the review of currently proven and emerging technologies that could mitigate the drilling operational deficiencies and instabilities that could hinder operational performance activities and the economic part of drilling development with great effort to minimize their environmental footprint. Drilling system design and operations are among the major aspects and cost-effective endeavors of the oil and gas industries, which are therefore technology dependent. They are also considered to be among the most expensive operations in the world, as they require huge expenses daily. Drilling success, depending on prevalent conditions, is a function of several general factors. These include the selection of the best technologies and tools, procedural optimization, concrete problem-solving, accurate prediction, and rapid decision-making. Consequently, any sorts of tools or advanced technologies that can improve the time-efficient operational and economic performance of drilling activities are essential and demanded. The paper provides a review of available technologies and developmental innovations based on both company-based and academic research-enabled drilling solutions over the past 5 years in the field of drilling systems and technological design. The paper further highlighted potential technologies that could be tapped in from other industries and could possibly be adopted by pushing the conventional boundaries of drilling operations.

scholarly journals Geomorphic contexts and science focus of the Zhurong landing site on Mars

2021 ◽  
Author(s):  
Jianjun Liu ◽  
Chunlai Li ◽  
Rongqiao Zhang ◽  
Wei Rao ◽  
Xiaofeng Cui ◽  
...  
Keyword(s):  
Landing Site ◽  
Formation Mechanisms ◽  
High Resolution Imaging ◽  
Water Ice ◽  
Subsurface Structures ◽  
In Situ Investigation ◽  
Imaging Camera ◽  
Resolution Imaging ◽  
Shed Light

AbstractAs part of the Tianwen-1 mission, the Zhurong rover successfully touched down in southern Utopia Planitia on 15 May 2021. On the basis of the new sub-metre-resolution images from the High Resolution Imaging Camera on board the Tianwen-1 orbiter, we determined that the Zhurong rover landed at 109.925° E, 25.066° N at an elevation of −4,099.4 m. The landing site is near the highland–lowland boundary1 and multiple suspected shorelines2–7. Under the guidance of the remote sensing survey, the Zhurong rover is travelling south for specific in situ investigation. Supported by the six payloads on board the rover8, its initial key targets are rocks, rocky fields, transverse aeolian ridges and subsurface structures along the path. Extended investigation will aim at troughs and cones in the distance. A better understanding of the formation mechanisms of these targets may shed light on the historical volcanism and water/ice activities within the landing area, as well as the activities of the wind. These results may reveal the characteristics and evolution of the ancient Martian environment and advance the exploration of the habitability of ancient Mars.

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