scholarly journals ASSESSMENT OF POSSIBLE IN-SITU FORMATION OF HYDRATE DURING GAS PRODUCTION FOR THE CONDITIONS OF THEGAS FIELD YUZNO-RUSSKOE

2016 ◽  
pp. 93-98 ◽  
Author(s):  
N. G. Musakaev ◽  
S. L. Borodin ◽  
M. K. Khasanov
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Hydrate Formation ◽  
Gas Production ◽  
The Real ◽  
Productive Stratum ◽  
In Situ Formation ◽  
Temperature And Pressure ◽  
Bottomhole Pressure

To assess the possibility of hydrate formation during gas production a mathematical model has been developed. This model takes into account the real properties of gas, the adiabatic and throttling effects. Also, the computer program has been written, which allows calculating the distributions of the main parameters in the productive stratum. The analysis of the bottomhole pressure, permeability and porosity influence on the character of distribution of temperature and pressure in the reservoir has been carried out.

Methane-Hydrate-Formation Processes in Methane/Water Bubbly Flows

SPE Journal ◽  
2016 ◽  
Vol 22 (03) ◽  
pp. 746-755 ◽  
Author(s):  
T.. Shimizu ◽  
Y.. Yamamoto ◽  
N.. Tenma
Keyword(s):  
Methane Hydrate ◽  
Hydrate Formation ◽  
Production Method ◽  
Gas Production ◽  
Bubbly Flows ◽  
Turbulent Shear ◽  
Formation Processes ◽  
Flow Loop ◽  
Offshore Production

Summary Offshore natural-gas production from methane-hydrate (MH) reservoirs has received considerable attention. In this study, the offshore production method is briefly described, followed by the flow loop experiments performed to investigate the formation processes of MH in methane-in-water bubbly flows. Transient processes of phase transformation are characterized by phase paths, flow morphologies, pump heads, and in-situ particle-size measurements. It is realized that an MH slurry is generated by MH shells covering unconverted bubbles, whereas it can be transformed into a colloidal flow with fine crystalline particles under an intense turbulent shear. This study suggests that, in practice, the flow pattern under MH formation would be determined by the phase path and the flow velocity in the pipeline, which is one of the important factors considered in the evaluation of flow-assurance risks.

Increasing Coal Absolute Permeability in the San Juan Basin Fruitland Formation

1998 ◽  
Vol 1 (03) ◽  
pp. 201-206 ◽  
Author(s):  
M.J. Mavor ◽  
J.E. Vaughn
Keyword(s):  
Test Data ◽  
Simulation Models ◽  
Gas Production ◽  
Absolute Permeability ◽  
San Juan ◽  
Well Test ◽  
San Juan Basin ◽  
M Theory ◽  
Bottomhole Pressure

Summary Recently measured data show that the absolute permeability of coal natural fracture is increasing significantly with continued gas production in the San Juan basin Fruitland formation. This phenomenon caused gas-production rates to be many times greater than expected from early production history. The phenomenon also caused producing bottomhole pressures to increase when gas rates were constant, opposite from that expected from conventional applications of Darcy's law. The increase in absolute permeability caused by gas desorption has been measured on cores, but, until recently, there was no verification that this phenomenon occurs in situ. Palmer and Mansoori (P&M) presented a new theory and showed how this theory matched gas- and water-production rates and estimated bottomhole-pressure data for a high-deliverability San Juan basin Fruitland formation coal-gas well. However, Palmer and Mansoori had no transient pressure data to support in-situ permeability changes. This paper documents data from drill stem tests (DST's) and shut-in tests with analyses there of and additional production-rate and pressure behaviors that support the P&M theory. The well-test data were measured in three wells completed in the San Juan basin Fruitland formation coal seams located under the Valencia Canyon (VC) area. These wells, VC 29-4, VC 32-1, and VC 32-4, are located in Sections 29 and 32, T33N, RllW, La Plata County, Colorado, and operated by EnerVest San Juan Operating LLC. In addition to the well-test data, EnerVest and the Gas Research Inst. (GRI) collected extensive formation-evaluation data and performed detailed analyses that allowed a thorough description of the area. Although there are other wells operated by EnerVest in the area, well-test data were not available from the other wells to determine the absolute permeability estimates; therefore, these wells are not discussed in this paper. The P&M theory was calibrated with well-test-derived absolute permeability estimates and published coal-shrinkage data. Reservoir simulation models, based on the calibrated theory, matched the unusual producing, bottomhole-pressure behavior. Without the P&M theory it was not possible to match pressure behavior or permeability estimates with reasonable variations of reservoir properties input into the reservoir-simulation models. The remainder of this paper summarizes the well-test analysis results from the three wells and, for brevity, one set of well-test data and one simulation study. The well-test data and simulation studies for the other wells were similar to the examples.

scholarly journals Hydrate Formation and Decomposition Regularities in Offshore Gas Reservoir Production Pipelines

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 248 ◽  
Author(s):  
Na Wei ◽  
Wantong Sun ◽  
Yingfeng Meng ◽  
Jinzhou Zhao ◽  
Bjørn Kvamme ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Numerical Solutions ◽  
Sea Water ◽  
Hydrate Formation ◽  
Gas Production ◽  
Gas Reservoir ◽  
Solution Algorithms ◽  
Wellbore Pressure ◽  
Wellbore Temperature ◽  
Temperature And Pressure

In recent years, the exploitation and utilization of offshore oil and gas resources have attracted more attention. In offshore gas reservoir production, wellbore temperature and pressure change continuously when water-bearing natural gas flows upward. The wellbore temperature is also affected by the low-temperature sea water. The combination of temperatures and pressures controlled by the upward flow, and cooling from the surrounding seawater frequently leads to the conditions of temperature and pressure for hydrate formation. This can lead to pipeline blockage and other safety accidents. In this study, we utilize mathematical models of hydrate phase equilibrium, wellbore temperature, wellbore pressure to study hydrate formation and decomposition in offshore gas reservoir production. Numerical solution algorithms are developed and numerical solutions are validated. The sensitivity influence of different parameters on the regions and regularities of hydrate formation and decomposition in wellbores are obtained through numerical simulations. It is found that increased daily gas production, water content, or geothermal gradient in offshore gas reservoir production pipelines results in less hydrate formation in the wellbores. Accordingly, the risk of wellbore blockage decreases and production safety is maintained. Decreased tubing head pressure or seawater depth results in similar effects. The result of this study establishes a set of prediction methods for hydrate formation and decomposition that can be used in the development of guidelines for safe construction design.

The lake ecosystem simulation program

1995 ◽  
Vol 31 (8) ◽  
pp. 367-370
Author(s):  
J. Heringa ◽  
H. Hylkema ◽  
M. Kroes ◽  
E. Ludden ◽  
P. G. van Schaick Zillesen
Keyword(s):  
Mathematical Model ◽  
Water Resources ◽  
Computer Program ◽  
Water Resources Management ◽  
Lake Ecosystem ◽  
Original Research ◽  
Ecological Processes ◽  
Resources Management ◽  
Lake Ecology ◽  
Ecosystem Simulation

The computer program LAKE simulates a shallow lake ecosystem. The program is based on a mathematical model. In the model the most important aspects of several models for water resources management are integrated (Collins and Wlosinski, 1988; Jørgensen, 1976; Jørgensen et al., 1978; Scheffer, 1988). Furthermore, the model describes several ecological processes that have not yet been described by lake-ecosystem models so far. In the computer program, the mathematical model and an advanced, object oriented, user interface are combined. Following this approach the use of the original research models was extended to a use for the purpose of teaching lake ecology. We suggest that the same approach may be followed to open research models to other groups concerned with water resources management, such as management authorities, industry, agricultural extension, nature conservation and recreation.

Real-life Field Studies of the NOx Removing Properties of Photocatalytic Surfaces in Roskilde and Copenhagen Airport, Denmark

2020 ◽  
Vol 01 ◽  
Author(s):  
Henrik Jensen ◽  
Pernille D. Pedersen
Keyword(s):  
Air Quality ◽  
High Stability ◽  
Reference Site ◽  
Real Life ◽  
Field Studies ◽  
The Real ◽  
Before And After ◽  
Parking Lot ◽  
Photocatalytic Concrete

Aims: To evaluate the real-life effect of photocatalytic surfaces on the air quality at two test-sites in Denmark. Background: Poor air quality is today one of the largest environmental issues, due to the adverse effects on human health associated with high levels of air pollution, including respiratory issues, cardiovascular disease (CVD), and lung cancer. NOx removal by TiO2 based photocatalysis is a tool to improve air quality locally in areas where people are exposed. Methods: Two test sites were constructed in Roskilde and Copenhage airport. In Roskilde, the existing asphalt at two parking lots was treated with TiO2 containing liquid and an in-situ ISO 22197-1 test setup was developed to enable in-situ evaluation of the activity of the asphalt. In CPH airport, photocatalytic concrete tiles were installed at the "kiss and fly" parking lot, and NOx levels were continuously monitored in 0.5 m by CLD at the active site and a comparable reference site before and after installation for a period of 2 years. Results: The Roskilde showed high stability of the photocatalytic coating with the activity being largely unchanged over a period of 2 years. The CPH airport study showed that the average NOx levels were decreased by 12 % comparing the before and after NOx concentrations at the active and reference site. Conclusion: The joined results of the two Danish demonstration projects illustrate a high stability of the photocatalytic coating as well as a high potential for improvements of the real-life air quality in polluted areas.

scholarly journals Formation of compact systems of super-Earths via dynamical instabilities and giant impacts

2019 ◽  
Vol 491 (4) ◽  
pp. 5595-5620 ◽  
Author(s):  
Sanson T S Poon ◽  
Richard P Nelson ◽  
Seth A Jacobson ◽  
Alessandro Morbidelli
Keyword(s):  
Initial Conditions ◽  
Post Processing ◽  
Significant Modification ◽  
Kepler Mission ◽  
Giant Impacts ◽  
Low Mass ◽  
In Situ Formation ◽  
Dynamical Instabilities ◽  
Gaseous Envelopes

ABSTRACT The NASA’s Kepler mission discovered ∼700 planets in multiplanet systems containing three or more transiting bodies, many of which are super-Earths and mini-Neptunes in compact configurations. Using N-body simulations, we examine the in situ, final stage assembly of multiplanet systems via the collisional accretion of protoplanets. Our initial conditions are constructed using a subset of the Kepler five-planet systems as templates. Two different prescriptions for treating planetary collisions are adopted. The simulations address numerous questions: Do the results depend on the accretion prescription?; do the resulting systems resemble the Kepler systems, and do they reproduce the observed distribution of planetary multiplicities when synthetically observed?; do collisions lead to significant modification of protoplanet compositions, or to stripping of gaseous envelopes?; do the eccentricity distributions agree with those inferred for the Kepler planets? We find that the accretion prescription is unimportant in determining the outcomes. The final planetary systems look broadly similar to the Kepler templates adopted, but the observed distributions of planetary multiplicities or eccentricities are not reproduced, because scattering does not excite the systems sufficiently. In addition, we find that ∼1 per cent of our final systems contain a co-orbital planet pair in horseshoe or tadpole orbits. Post-processing the collision outcomes suggests that they would not significantly change the ice fractions of initially ice-rich protoplanets, but significant stripping of gaseous envelopes appears likely. Hence, it may be difficult to reconcile the observation that many low-mass Kepler planets have H/He envelopes with an in situ formation scenario that involves giant impacts after dispersal of the gas disc.

A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

1986 ◽  
Vol 18 (7-8) ◽  
pp. 239-248 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dwang Ho Lee ◽  
Sang Eun Lee
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Biomass Concentration ◽  
Gas Production ◽  
Septic Tank ◽  
Volatile Acid ◽  
Hydraulic Residence Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

scholarly journals Method for determining the thermal conductivity of in situ formation rock using drilling cuttings

AIP Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 065015
Author(s):  
Fu Yi ◽  
Xupeng Qi ◽  
Xuexin Zheng ◽  
Huize Yu ◽  
Wenming Bai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
In Situ Formation
Sign in / Sign up

Export Citation Format

Share Document