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.

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 Numerical Study on the Influence of Well Layout on Electricity Generation Performance of Enhanced Geothermal Systems

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1474
Author(s):  
Yuchao Zeng ◽  
Fangdi Sun ◽  
Haizhen Zhai
Keyword(s):  
Energy Efficiency ◽  
Electric Power ◽  
Electricity Generation ◽  
Horizontal Well ◽  
Production Performance ◽  
Electricity Production ◽  
Fracture Permeability ◽  
Fracture Spacing ◽  
Vertical Well ◽  
Well Spacing

The energy efficiency of the enhanced geothermal system (EGS) measures the economic value of the heat production and electricity generation, and it is a key indicator of system production performance. Presently there is no systematic study on the influence of well layout on the system energy efficiency. In this work we numerically analyzed the main factors affecting the energy efficiency of EGS using the TOUGH2-EOS1 codes at Gonghe Basin geothermal field, Qinghai province. The results show that for the reservoirs of the same size, the electric power of the three horizontal well system is higher than that of the five vertical well system, and the electric power of the five vertical well system is higher than that of the three vertical well system. The energy efficiency of the three horizontal well system is higher than that of the five vertical well system and the three vertical well system. The reservoir impedance of the three horizontal well system is lower than that of the three vertical well system, and the reservoir impedance of the three vertical well system is lower than that of the five vertical system. The sensitivity analysis shows that well spacing has an obvious impact on the electricity production performance; decreasing well spacing will reduce the electric power, reduce the energy efficiency and only have very slight influence on the reservoir impedance. Fracture spacing has an obvious impact on the electricity production performance; increasing fracture spacing will reduce the electric power and reduce the energy efficiency. Fracture permeability has an obvious impact on the electricity production performance; increasing fracture permeability will improve the energy efficiency and reduce the reservoir impedance.

scholarly journals A Solution to Sand Production from Natural Gas Hydrate Deposits with Radial Wells: Combined Gravel Packing and Sand Screen

2022 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
Yiqun Zhang ◽  
Wei Wang ◽  
Panpan Zhang ◽  
Gensheng Li ◽  
Shouceng Tian ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Control Method ◽  
Gas Production ◽  
Sand Production ◽  
Natural Gas Hydrate ◽  
Vertical Well ◽  
Sand Control ◽  
Gravel Packing ◽  
Radial Well

Sand production is one of the main problems restricting the safe, efficient and sustainable exploitation of marine natural gas hydrate. To explore the sand-control effects of gravel packing, experiments that simulate hydrate extraction in the water-rich environment were conducted with designed hydrate synthesis and exploitation devices. Three sand control completion methods, including 120 mesh sand screen, 400 mesh sand screen, 120 mesh sand screen combined with gravel packing, are adopted. Sand and gas production rates were compared under different well types and sand control completion methods. Results show that the gas production modes of radial wells and vertical wells are almost the same at the same time due to the small experimental scale and high permeability. The sand production of the vertical well with gravel packing combined with a sand-control screen is 50% lower than that of the vertical well with sand-control screens only. Radial well with gravel packing combined with sand-control screens produced 87% less sand than screen mesh alone. The cumulative gas production and recovery rates of a radial well with the composite sand control method are better than those without gravel packing in the same development time.

scholarly journals The Effects of the Length and Conductivity of Artificial Fracture on Gas Production from a Class 3 Hydrate Reservoir

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7513
Author(s):  
Shilong Shang ◽  
Lijuan Gu ◽  
Hailong Lu
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Energy Resource ◽  
Gas Production ◽  
Production Performance ◽  
Natural Gas Hydrate ◽  
Conductivity Method ◽  
Fracture Length ◽  
Hydrate Reservoir ◽  
Artificial Fracture

Natural gas hydrate is considered as a potential energy resource. To develop technologies for the exploitation of natural gas hydrate, several field gas production tests have been carried out in permafrost and continental slope sediments. However, the gas production rates in these tests were still limited, and the low permeability of the hydrate-bearing sediments is identified as one of the crucial factors. Artificial fracturing is proposed to promote gas production rate by improving reservoir permeability. In this research, numerical studies about the effect of fracture length and fluid conductivity on production performance were carried out on an artificially fractured Class 3 hydrate reservoir (where the single hydrate zone is surrounded by an overlaying and underlying hydrate-free zone), in which the equivalent conductivity method was applied to depict the artificial fracture. The results show that artificial fracture can enhance gas production by offering an extra fluid flow channel for the migration of gas released from hydrate dissociation. The effect of fracture length on production is closely related to the time frame of production, and gas production improvement by enlarging the fracture length is observed after a certain production duration. Through the production process, secondary hydrate formation is absent in the fracture, and the high conductivity in the fracture is maintained. The results indicate that the increase in fracture conductivity has a limited effect on enhancing gas production.

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 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.

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