scholarly journals Numerical Investigation on Gas Production Performance in Methane Hydrate of Multilateral Well under Depressurization in Krishna-Godavari Basin

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Xin Xin ◽  
Si Li ◽  
Tianfu Xu ◽  
Yilong Yuan
Keyword(s):  
Production Rate ◽  
Production Efficiency ◽  
Gas Production ◽  
Geometric Parameters ◽  
Production Performance ◽  
Production Volume ◽  
Hydrate Decomposition ◽  
Single Well ◽  
Influence Radius ◽  
Lateral Branches

Nature gas hydrate is a new kind of clean and potential resources. Depressurization is regarded as the most effective and promising hydrate production technology. One of the key points in improving the gas production effectiveness of depressurization is whether pressure gradient could transmit in strata effectively. Single well method is widely used in hydrate exploit which is circumscribed in expanding the range of hydrate decomposition. Consequently, the well structure and production strategy needs to be optimized for improving the gas recovery efficiency. The multilateral well technology is proposed for increasing the gas productivity of the reservoir greatly by increasing the multilateral branches. In this paper, we established a numerical simulation model based on the geological data NGHP-02-16 site in the KG basin to evaluate the gas production performance of the reservoir by depressurization. It mainly focuses on investigating the gas production performance of multilateral wells with different combinations of geometric parameters of multilateral branches, such as different dip angle, numbers, and spacing of lateral branches. The result shows that the multilateral well method can effectively increase the gas production rate with the water production rate increase slightly. The cumulative gas production volume of a single vertical well is about 2.85 × 10 6   m 3 , while it is of the multilateral well can reach 4.18 × 10 6   m 3 during a one-year production. The well interference, the effective influence radius of each multilateral branch, and the vertical depth of the lateral branch are the main factors which affect the gas production efficiency of the multilateral well. The optimization of the geometric parameters of lateral should consider not only the gas production efficiency but also the well interference between the lateral branches.

scholarly journals Anaerobic Co-Digestion of Oil Sludge with Corn Stover for Efficient Biogas Production

2020 ◽  
Vol 12 (5) ◽  
pp. 1861
Author(s):  
Qian Yang ◽  
Chenxi Zhang ◽  
Lei Li ◽  
Weijie Xu
Keyword(s):  
Corn Stover ◽  
Production Efficiency ◽  
Biogas Production ◽  
Gas Production ◽  
Production Performance ◽  
Raw Material ◽  
Oil Sludge ◽  
Smelting Process ◽  
Fundamental Parameter ◽  
Production Volume

The feasibility of anaerobic co-digestion for the utilization of oil sludge was verified using corn stover, to assess the influence of different raw material ratios and inoculum volumes on the properties of the generated gas. The anaerobic co-digestion method is a novel treatment technology, which may help to solve the problem of pollution by hazardous waste oil sand from the oil exploitation and smelting process. Results showed that single-oil sludge was not suitable for gas production as a digestive substrate due to the lack of organic materials and possible hazardous materials. With the increase in the quality of exogenous organic matter (corn stover), the cumulative gas production volume was proportional to the amount of corn stover material added. It was established that when the mass ratio of corn stover to oil sludge was 4:1, the gas production performance was optimal, with a cumulative gas yield of 1222.5 mL using an inoculum volume of 30 mL. The results of this study provide a fundamental parameter baseline for the treatment of oil sludge and the improvement of gas production efficiency.

An Early-Time Model for Drawdown Testing of a Hydrate-Capped Gas Reservoir

2009 ◽  
Vol 12 (04) ◽  
pp. 595-609 ◽  
Author(s):  
Shahab Gerami ◽  
Mehran Pooladi-Darvish
Keyword(s):  
Gas Hydrate ◽  
Gas Production ◽  
Production Performance ◽  
Gas Reservoir ◽  
Unconventional Gas ◽  
Free Gas ◽  
Hydrate Decomposition ◽  
Hydrate Reservoir ◽  
Wellbore Pressure ◽  
Hydrate Reservoirs

Summary Development of natural gas hydrates as an energy resource has gained significant interest during the past decade. Hydrate reservoirs may be found in different geologic settings including deep ocean sediments and arctic areas. Some reservoirs include a free-gas zone beneath the hydrate and such a situation is referred to as a hydrate-capped gas reservoir. Gas production from such a reservoir could result in pressure reduction in the hydrate cap and endothermic decomposition of hydrates. Well testing in conventional reservoirs is used for estimation of reservoir and near-wellbore properties. Drawdown testing in a hydrate-capped gas reservoir needs to account for the effect of gas from decomposing hydrates. This paper presents a 2D (r,z) mathematical model for a constant-rate drawdown test performed in a well completed in the free-gas zone of a hydrate-capped gas reservoir during the earlytime production. Using energy and material balance equations, the effect of endothermic hydrate decomposition appears as an increased compressibility in the resulting governing equation. The solution for the dimensionless wellbore pressure is derived using Laplace and finite Fourier cosine transforms. The solution to the analytical model was compared with a numerical hydrate reservoir simulator across some range of hydrate reservoir parameters. The use of this solution for determination of reservoir properties is demonstrated using a synthetic example. Furthermore, the solution may be used to quantify the contribution of hydrate decomposition on production performance. Introduction In recent years, demands for energy have stimulated the development of unconventional gas resources, which are available in enormous quantities around the world. Gas hydrate as an unconventional gas resource may be found in two geologic settings (Sloan 1991):on land in permafrost regions, andin the ocean sediments of continental margins. During the last decade, extensive efforts consisting of detection of the hydrate-bearing areas, drilling, logging, coring of the intervals, production pilot-testing, and mathematical modeling of hydrate reservoirs have been pursued to evaluate the potential of gas production from these gas-hydrate resources.

scholarly journals A Hybrid Model for Simulating Fracturing Fluid Flowback in Tight Sandstone Gas Wells considering a Three-Dimensional Discrete Fracture

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Suran Wang ◽  
Yuhu Bai ◽  
Bingxiang Xu ◽  
Yanzun Li ◽  
Ling Chen ◽  
...  
Keyword(s):  
Production Rate ◽  
Two Phase Flow ◽  
Three Dimensional ◽  
Gas Production ◽  
Production Performance ◽  
Phase Flow ◽  
Fracture Permeability ◽  
Tight Sandstone ◽  
Two Phase ◽  
Discrete Fracture

Abstract Two-phase (gas+water) flow is quite common in tight sandstone gas reservoirs during flowback and early-time production periods. However, many analytical models are restricted to single-phase flow problems and three-dimensional fracture characteristics are seldom considered. Numerical simulations are good choices for this problem, but it is time consuming in gridding and simulating. This paper presents a comprehensive hybrid model to characterize two-phase flow behaviour and predict the production performance of a fractured tight gas well with a three-dimensional discrete fracture. In this approach, the hydraulic fracture is discretized into several panels and the transient flow equation is solved by the finite difference method numerically. A three-dimensional volumetric source function and superposition principle are deployed to capture the flow behaviour in the reservoir analytically. The transient responses are obtained by coupling the flow in the reservoir and three-dimensional discrete fracture dynamically. The accuracy and practicability of the proposed model are validated by the numerical simulation result. The results indicate that the proposed model is highly efficient and precise in simulating the gas/water two-phase flow and evaluating the early-time production performance of fractured tight sandstone gas wells considering a three-dimensional discrete fracture. The results also show that the gas production rate will be overestimated without considering the two-phase flow in the hydraulic fracture. In addition, the influences of fracture permeability, fracture half-length, and matrix permeability on production performance are significant. The gas production rate will be higher with larger fracture permeability at the early production period, but the production curves will merge after fracturing fluid flows back. A larger fracture half-length and matrix permeability can enhance the gas production rate.

scholarly journals Rate Decline Analysis for Limited-Entry Well in Abnormally High-Pressured Composite Naturally Fractured Gas Reservoirs

2019 ◽  
Vol 9 (9) ◽  
pp. 1821
Author(s):  
Mingtao Wu ◽  
Xiaodong Wang ◽  
Wenqi Zhao ◽  
Lun Zhao ◽  
Meng Sun ◽  
...  
Keyword(s):  
Production Rate ◽  
High Efficiency ◽  
Negative Impact ◽  
Gas Production ◽  
Production Performance ◽  
Gas Reservoirs ◽  
Naturally Fractured ◽  
Limited Entry ◽  
Permeability Anisotropy ◽  
Stress Dependent

Most naturally fractured gas reservoirs in China exhibit strongly heterogeneous, abnormally high-pressured and, stress-sensitive behaviors. In this work, a semianalytical solution is developed to study the production performance for limited-entry well in composite naturally fractured formations. The pressure-dependent porosity and permeability, anisotropy and limited-entry characteristics are taken into consideration. Furthermore, conventional Warren-Root model is amended to accommodate for permeability anisotropy. Laplace and finite Fourier cosine transforms are used to solve the diffusivity equations. The model is verified on the basis of previous literature’s results and data of a field example from Moxi gas field in Southwest China. Through the parameters sensitivity analysis, the effects of prevailing factors on production performance are investigated. Results indicate that a large inner region radius and high mobility ratio can improve gas production rate in the early stage, while they also lead to a drastic decline of production rate in the late stage. Large permeability stress-dependent coefficient and low penetrated interval both have a negative impact on production rate. With its high efficiency and simplicity, this proposed approach can serve as a convenient tool to evaluate the behavior of partially penetrated production well in abnormally high-pressured composite naturally fractured gas reservoirs.

scholarly journals Influence of Intrinsic Permeability on the Production Performance of Shenhu Hydrate Sediment through Depressurization

2019 ◽  
Vol 118 ◽  
pp. 01008
Author(s):  
Yingrui Ma ◽  
Shuxia Li ◽  
Didi Wu
Keyword(s):  
Production Rate ◽  
Gas Production ◽  
Production Performance ◽  
Absolute Permeability ◽  
Reservoir Pressure ◽  
Intrinsic Permeability ◽  
Reservoir Temperature ◽  
Natural Gas Hydrate ◽  
Hydrate Dissociation ◽  
Hydrate Reservoirs

Natural gas hydrate(NGH) is a clean resource with huge reserves. The depressurization method is an economical and effective exploitation method. In the process of depressurization, reservoir absolute permeability has an important influence on production results. Based on the data of Shenhu hydrate reservoirs, this paper established a depressurization production numerical simulation model. Then, the production performances such as pressure, temperature, gas production rate, cumulative gas production, and hydrate dissociation effect are all studied under different permeability conditions.study the change of reservoir pressure, gas production rate, cumulative gas production, reservoir temperature change and hydrate dissociation effect under different permeability conditions. Results show that higher permeability is conducive to the depressurization of hydrate reservoirs.

scholarly journals Comparison and Optimization of Methane Hydrate Production Process Using Different Methods in a Single Vertical Well

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 124 ◽  
Author(s):  
Yun-Pei Liang ◽  
Shu Liu ◽  
Qing-Cui Wan ◽  
Bo Li ◽  
Hang Liu ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Natural Gas ◽  
Driving Force ◽  
Production Efficiency ◽  
Electric Heating ◽  
Gas Production ◽  
Production Performance ◽  
Water Production ◽  
Dual Decomposition ◽  
Vertical Well

Natural gas hydrate (NGH) is a potential type of clean and efficient energy that is widely distributed in the ocean and permafrost, and most of the present researches are mainly focused on finding out efficient exploitation methods. Taking the effects of natural gas productivity and extraction time into account, one of the exploitation methods that are most commonly investigated is depressurization combined with thermal stimulation. However, few studies considered the effect of different mining methods on NGH production in vertical wells, especially aiming at the in-situ electric heating without mass injection and the comparison of production efficiency in different modes. Considering the current research status, four exploitation methods which are pure depressurization (PD), pure heating (PH), simultaneous depressurization combined with electric heating (SDH) and huff and puff (H&P) were carried out in this paper to study the influences of different production methods on NGH exploitation in a vertical well. Some parameters such as gas production (VP), water production (CP) and the energy efficiency (η) were investigated to evaluate the production performance of these methods. The results suggest that the temperature in the reactor is affected by the exploitation methods as well as the water production during exploitation. For PD, although it has no extra energy consumption, the longest production period is seen in it due to the insufficient pressure driving force. On the contrary, the NGH cannot be completely exploited only triggered by heating driving force with PH method. So there is a limited decomposition effect with it. Taking the gas production time, the VP, and the NGH dissociation rate into account, the production effects of SDH are more beneficial than other methods as the dual decomposition driving force was adopted in it. Furthermore, a reasonable heating power can result in a better production performance. On the other hand, promoted by pressure difference and discontinuous heating, H&P shows its obvious advantage in shortening production duration and improving energy efficiency, which is therefore believed to have the best commercial exploitation value among the four methods.

Effect of Substrate Concentration on Hydrogen Production from Fermentation of Sugar Wastewater

2013 ◽  
Vol 409-410 ◽  
pp. 235-241
Author(s):  
Zheng Zhou ◽  
Kai Liu ◽  
Qiu Yang He
Keyword(s):  
Hydrogen Production ◽  
Production Rate ◽  
Substrate Concentration ◽  
Anaerobic Fermentation ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Gas Production ◽  
Production Performance ◽  
Volatile Acid ◽  
Hydrogen Production Rate

The biological hydrogen production by the sugar wastewater is an effective way to achieve the reclamation. In this paper, the effect of substrate concentration on the hydrogen production is discussed through employing the self-made continuous flow anaerobic fermentation hydrogen production reactor, taking the sludge in urban sewage treatment plant as the inoculated sludge and the simulated sugar wastewater as the substrate. The experimental results show that the best hydrogen production effect can be obtained when the temperature is (37±1) °C, HRT is 7h, the water alkalinity is around 530mg/L and the substrate concentration is 5000mg/L, namely the organic load is 60kgCOD/(m3·d). The volumes of gas production and hydrogen production both reach the maximum. The average values are respectively 36.2L/d and 21.8L/d. The obtained hydrogen production rate is 0.93kgCOD/(m3·d). During the whole process, the proportion of volatile acid composition remains stable, which is the butyric acid-type fermentation. When the concentration of COD is increased to 6000-8000mg/L, the ability of hydrogen production of system will be significantly dropped due to the increase of pH of system. The hydrogen production performance can be restored through artificially and timely lowering the water alkalinity. However, the hydrogen production rate will be decreased compared to the previous situation.

scholarly journals Effect of Perforation Interval Design on Gas Production from the Validated Hydrate-Bearing Deposits with Layered Heterogeneity by Depressurization

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Yingli Xia ◽  
Tianfu Xu ◽  
Yilong Yuan ◽  
Xin Xin
Keyword(s):  
Energy Demand ◽  
Production Efficiency ◽  
Gas Production ◽  
Production Performance ◽  
Gas Release ◽  
Methane Recovery ◽  
Hydrate Dissociation ◽  
Gas Recovery ◽  
Hydrate Reservoir ◽  
Production Wells

Natural gas hydrate is considered as one of the best potential alternative resource to address the world’s energy demand. The available geological data at the Mallik site of Canada indicates the vertical heterogeneities of hydrate reservoir petrophysical properties. According to the logging data and sample analysis results at the Mallik 2L-38 well, a 2D model of geologically descriptive hydrate-bearing sediments was established to investigate the multiphase flow behaviors in hydrate reservoir induced by gas recovery and the effects of perforation interval on gas production performance. Firstly, the constructed model with vertical heterogeneous structures of permeability, porosity, and hydrate saturation was validated by matching the measured data in the Mallik 2007 test. The excessive residual methane in the hydrate reservoir observed in simulated results indicates insufficient gas production efficiency. For more effective methane recovery from a hydrate reservoir, the effect of perforation interval on long-term gas production performance was investigated based on the validated reservoir model. The simulation results suggest that both the location and length of the perforation interval have significant impact on hydrate dissociation behavior, while the gas production performance is mainly affected by the length of the perforation interval. To be specific, an excellent gas release performance is found in situations where the perforation interval is set at the interface between a hydrate reservoir and an underlying water-saturated zone. By increasing the perforation interval lengths of 5 m, 8 m, and 10 m, the gas release volumes from hydrate dissociation and gas production volumes from production wells are increased by 34%, 52%, and 57% and 37%, 58%, and 62%, respectively.

scholarly journals Effect of electrolytes on the self-protection of natural gas hydrate decomposition

2021 ◽  
Vol 18 (4) ◽  
pp. 482-491
Author(s):  
Haixiang Zhang ◽  
Jinze Xu ◽  
Zhandong Li ◽  
Xin Tian ◽  
Wenbo Meng ◽  
...  
Keyword(s):  
Production Rate ◽  
Methane Hydrate ◽  
Inhibitory Effect ◽  
Gas Production ◽  
The Self ◽  
Natural Gas Hydrate ◽  
Protection Effect ◽  
Hydrate Decomposition ◽  
Na Ions ◽  
Self Protection

Abstract This paper presents an experimental study of methane hydrate decomposition with different concentrations of electrolytes Na+ and K+, with the aim of exploring the electrolyte's behaviour characteristics shown in its effect on the self-protection effect of methane hydrate during decomposition. The study used an experimental device for hydrate synthesis and decomposition. It focuses on the effect of electrolytes on the self-protection effect of methane hydrate during the self-protection effect during methane hydrate decomposition. (i) Na+ ions have an inhibitory effect on self-protection, whereas K+ ions do not have a significant effect. (ii) There is a negative correlation between the hydrate self-protection effect and the concentration of Na+ ions. However, an excessive Na+ concentration can inhibit the hydrate gas production rate. (iii) The synergistic system of Na+ and K+ ions has a better inhibitory effect on the hydrate's self-protection effect than a single Na+ ion solution. As the concentration of the synergistic system increased, the hydrate gas production rate was not inhibited. However, in contrast to a single Na+ ion solution, when the concentration of the synergistic system was too high, the methane hydrate gas production rate was not inhibited because of the coexistence of cations.

Integrated Subsurface to Surface Modeling to Assess Reservoir Uncertainty Quantification to A Carbonate Reservoir

2020 ◽  
Author(s):  
A. Chaterine
Keyword(s):  
Uncertainty Quantification ◽  
Gas Production ◽  
Carbonate Reservoir ◽  
Production Volume ◽  
Production Forecast ◽  
Uncertainty Range ◽  
Field Development ◽  
Production Forecasting ◽  
Production Scheme ◽  
Rock Compressibility

This study accommodates subsurface uncertainties analysis and quantifies the effects on surface production volume to propose the optimal future field development. The problem of well productivity is sometimes only viewed from the surface components themselves, where in fact the subsurface component often has a significant effect on these production figures. In order to track the relationship between surface and subsurface, a model that integrates both must be created. The methods covered integrated asset modeling, probability forecasting, uncertainty quantification, sensitivity analysis, and optimization forecast. Subsurface uncertainties examined were : reservoir closure, regional segmentation, fluid contact, and SCAL properties. As the Integrated Asset Modeling is successfully conducted and a matched model is obtained for the gas-producing carbonate reservoir, highlights of the method are the following: 1) Up to ± 75% uncertainty range of reservoir parameters yields various production forecasting scenario using BHP control with the best case obtained is 335 BSCF of gas production and 254.4 MSTB of oil production, 2) SCAL properties and pseudo-faults are the most sensitive subsurface uncertainty that gives major impact to the production scheme, 3) EOS modeling and rock compressibility modeling must be evaluated seriously as those contribute significantly to condensate production and the field’s revenue, and 4) a proposed optimum production scenario for future development of the field with 151.6 BSCF gas and 414.4 MSTB oil that yields a total NPV of 218.7 MMUSD. The approach and methods implemented has been proven to result in more accurate production forecast and reduce the project cost as the effect of uncertainty reduction.

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