The outbursts of comet 29P/SW-1 and C/2020 R4 (ATLAS)

2021 ◽  
Author(s):  
Zhong-Yi Lin ◽  
Michael S. P. Kelly ◽  
Huen-Wing Ip
Keyword(s):  
Gas Production ◽  
Active Period ◽  
Production Rates ◽  
Preliminary Results ◽  
Long Period ◽  
Level Of Activity ◽  
Multi Wavelength ◽  
Dust Coma ◽  
Period Comet

<p>We present an analysis of the dynamic dust coma of Centaur 29P/Schewassmann-Wachmann 1 and long-period comet C/2020 R4 (Atlas). Comet P/SW1 has exhibited a considerable level of activity (so-called outbursts) since its discovery in 1925. In 2011, we found the morphology of comet P/SW 1 showed dust features in the form of jets, spirals and shells. This year, we have obtained multi-wavelength observations of 29P/SW 1's dust coma at Lulin observatory and we will present preliminary results including the morphological analysis and the colour (B-V, V-R, and R-I) investigation of the dust coma when comet is at quiet and active period.</p> <p>At least three outbursts found within two weeks from comet Atlas is unusual for long-period comet. However, we didn’t find any new jet features and fragments from the morphology of comet Atlas. Except for the color investigation during the outburst, we will also give the dust/gas production rates in the comparison between pre- and post-outbursts.</p>

scholarly journals Non-gravitational forces and masses of some long-period comets. The cases of Hale-Bopp and Hyakutake

2009 ◽  
Vol 5 (S263) ◽  
pp. 85-88
Author(s):  
Andrea Sosa ◽  
Julio A. Fernández
Keyword(s):  
Gravitational Force ◽  
Critical Issue ◽  
Cometary Nucleus ◽  
Gas Production ◽  
Force Model ◽  
Good Representation ◽  
Production Rates ◽  
Sublimation Rate ◽  
Long Period ◽  
The Masses

AbstractBy means of a simple non-gravitational force model of the cometary nucleus, which relies on the observed light curves assumed to be a good representation of the water sublimation rate, we estimate the masses of a sample of long-period comets (LPCs).A critical issue of our method is the assumption of a correlation between visual heliocentric magnitudes and water production rates. This is a necessary assumption because of the sparse observational data of gas production rates (with the exception of very few comets like Hale-Bopp or Hyakutake). In this regard we present here a new correlation for LPCs. We also present the preliminary results for the masses of comets Hale-Bopp and Hyakutake.

Beginning of Activity in Long-period Comet C/2015 ER61 (PANSTARRS)

2017 ◽  
Vol 153 (5) ◽  
pp. 206 ◽  
Author(s):  
Karen J. Meech ◽  
Charles A. Schambeau ◽  
Kya Sorli ◽  
Jan T. Kleyna ◽  
Marco Micheli ◽  
...  
Keyword(s):  
Long Period ◽  
Period Comet

Advanced Well Completion Strategies to Improve Gas Production Deliverability in Marginal Tight Gas Reservoirs from an Onshore Abu Dhabi Gas Field

2021 ◽  
Author(s):  
Hajar Ali Abdulla Al Shehhi ◽  
Bondan Bernadi ◽  
Alia Belal Zuwaid Belal Al Shamsi ◽  
Shamma Jasem Al Hammadi ◽  
Fatima Omar Alawadhi ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Horizontal Wells ◽  
Gas Production ◽  
Abu Dhabi ◽  
Tight Gas ◽  
Production Rates ◽  
Well Productivity ◽  
Gas Saturation ◽  
Well Design ◽  
The Impact

Abstract Reservoir X is a marginal tight gas condensate reservoir located in Abu Dhabi with permeability of less than 0.05 mD. The field was conventionally developed with a few single horizontal wells, though sharp production decline was observed due to rapid pressure depletion. This study investigates the impact of converting the existing single horizontal wells into single long horizontal, dual laterals, triple laterals, fishbone design and hydraulic fracturing in improving well productivity. The existing wells design modifications were planned using a near reservoir simulator. The study evaluated the impact of length, trajectory, number of laterals and perforation intervals. For Single, dual, and triple lateral wells, additional simulation study with hydraulic fracturing was carried out. To evaluate and obtain effective comparisons, sector models with LGR was built to improve the simulation accuracy in areas near the wellbore. The study conducted a detailed investigation into the impact of various well designs on the well productivity. It was observed that maximizing the reservoir contact and targeting areas with high gas saturation led to significant increase in the well productivity. The simulation results revealed that longer laterals led to higher gas production rates. Dual lateral wells showed improved productivity when compared to single lateral wells. This incremental gain in the production was attributed to increased contact with the reservoir. The triple lateral well design yielded higher productivity compared to single and dual lateral wells. Hydraulic fracturing for single, dual, and triple lateral wells showed significant improvement in the gas production rates and reduced condensate banking near the wellbore. A detailed investigation into the fishbone design was carried out, this involved running sensitivity runs by varying the number of branches. Fishbone design showed considerable increment in production when compared to other well designs This paper demonstrates that increasing the reservoir contact and targeting specific areas of the reservoir with high gas saturation can lead to significant increase in the well productivity. The study also reveals that having longer and multiple laterals in the well leads to higher production rates. Hydraulic fracturing led to higher production gains. Fishbone well design with its multiple branches showed the most production again when compared to other well designs.

scholarly journals Iterative Analytical Solutions for Nonlinear Two-Phase Flow with Gas Solubility in Shale Gas Reservoirs

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaoji Shang ◽  
J. G. Wang ◽  
Zhizhen Zhang
Keyword(s):  
Capillary Pressure ◽  
Analytical Solutions ◽  
Shale Gas ◽  
Nonlinear Term ◽  
Two Phase Flow ◽  
Gas Production ◽  
Phase Flow ◽  
Gas Solubility ◽  
Production Rates ◽  
Two Phase

The governing equations of a two-phase flow have a strong nonlinear term due to the interactions between gas and water such as capillary pressure, water saturation, and gas solubility. This nonlinearity is usually ignored or approximated in order to obtain analytical solutions. The impact of such ignorance on the accuracy of solutions has not been clear so far. This study seeks analytical solutions without ignoring this nonlinear term. Firstly, a nonlinear mathematical model is developed for the two-phase flow of gas and water during shale gas production. This model also considers the effects of gas solubility in water. Then, iterative analytical solutions for pore pressures and production rates of gas and water are derived by the combination of travelling wave and variational iteration methods. Thirdly, the convergence and accuracy of the solutions are checked through history matching of two sets of gas production data: a China shale gas reservoir and a horizontal Barnett shale well. Finally, the effects of the nonlinear term, shale gas solubility, and entry capillary pressure on the shale gas production rate are investigated. It is found that these iterative analytical solutions can be convergent within 2-3 iterations. The solutions can well describe the production rates of both gas and water. The nonlinear term can significantly affect the forecast of shale gas production in both the short term and the long term. Entry capillary pressure and shale gas solubility in water can also affect shale gas production rates of shale gas and water. These analytical solutions can be used for the fast calculation of the production rates of both shale gas and water in the two-phase flow stage.

scholarly journals Do comet groups exist?

1985 ◽  
Vol 83 ◽  
pp. 353-363
Author(s):  
B.A. Lindblad
Keyword(s):  
Computer Program ◽  
Confidence Level ◽  
Computer Search ◽  
Orbital Elements ◽  
Similarity Parameter ◽  
The Real ◽  
Meteor Streams ◽  
Long Period ◽  
Random Samples ◽  
Period Comet

AbstractThe phenomena of comet groups, i.e. sets of comets that exhibit similarity in their orbital elements, is investigated. A computer program based on the D-criterion of orbital similarity is used to search for comet pairs and groups. The reality of the groups is tested by making computer searches in random samples of comet orbits.The data base for the study is 599 long-period comet orbits. The degree of orbital similarity within a comet group was first assumed to be identical to that encountered in meteor streams. The computer search at this level produced five comet pairs plus two groups with four and seven members, respectively. The latter two represented the eleven known members of the Kreutz group of sun-grazing comets. A comparison with searches in random samples showed that the two Kreutz groups were significant. There is a probability of 0.2 that the five comet pairs found in the real sample could be accidental formations.In a second study the orbital similarity parameter Ds was varied and the number of comet groups found in the real and synthetic comet populations was compared at each level of Ds. Apart from the Kreutz group of comets, the number of groups detected in the real comet sample was for all levels of orbital similarity only slightly higher than the average found in the random samples. At the 2σ confidence level we conclude that comet groups exhibit similarity in their orbital elements, that is no greater than might be expected by chance.

scholarly journals Biogeochemistry and the associated redox signature of co-produced water from coalbed methane wells in the Shizhuangnan block in the southern Qinshui Basin, China

2020 ◽  
Vol 38 (4) ◽  
pp. 1034-1053
Author(s):  
Yang Li ◽  
Shuheng Tang ◽  
Songhang Zhang ◽  
Zhaodong Xi ◽  
Pengfei Wang
Keyword(s):  
Coalbed Methane ◽  
Produced Water ◽  
Dissolved Inorganic Carbon ◽  
Gas Production ◽  
Redox Conditions ◽  
Effective Parameters ◽  
Production Rates ◽  
Qinshui Basin ◽  
Southern Qinshui Basin ◽  
Biogeochemical Parameters

To meet the global energy demands, the exploitation of coalbed methane has received increasing attention. Biogeochemical parameters of co-produced water from coalbed methane wells were performed in the No. 3 coal seam in the Shizhuangnan block of the southern Qinshui Basin (China). These biogeochemical parameters were firstly utilized to assess coal reservoir environments and corresponding coalbed methane production. A high level of Na+ and HCO3– and deuterium drift were found to be accompanied by high gas production rates, but these parameters are unreliable to some extent. Dissolved inorganic carbon (DIC) isotopes δ13CDIC from water can be used to distinguish the environmental redox conditions. Positive δ13CDIC values within a reasonable range suggest reductive conditions suitable for methanogen metabolism and were accompanied by high gas production rates. SO42–, NO3– and related isotopes affected by various bacteria corresponding to various redox conditions are considered effective parameters to identify redox states and gas production rates. Importantly, the combination of δ13CDIC and SO42– can be used to evaluate gas production rates and predict potentially beneficial areas. The wells with moderate δ13CDIC and negligible SO42– represent appropriate reductive conditions, as observed in most high and intermediate production wells. Furthermore, the wells with highest δ13CDIC and negligible SO42– exhibit low production rates, as the most reductive environments were too strict to extend pressure drop funnels.

Thermally induced multi-wavelength filtering in electro-optic long period Ti:LiNbO3 waveguide grating

2018 ◽  
Vol 124 (11) ◽  
Author(s):  
Yuan Chen ◽  
Rui-Qi Piao ◽  
Chao-Yang Zhang ◽  
Zi-Bo Zhang ◽  
Jia-Qi Xu ◽  
...  
Keyword(s):  
Thermally Induced ◽  
Waveguide Grating ◽  
Long Period ◽  
Electro Optic ◽  
Multi Wavelength ◽  
Wavelength Filtering
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