scholarly journals Dynamic production characteristics and effect analysis of combined gas production well of coalbed methane and tight gas

2021 ◽  
Author(s):  
Cheng Leli ◽  
Zhao Shaoze ◽  
Yin Senlin ◽  
Chen Gongyang ◽  
Chen Ling ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Production ◽  
Dense Layer ◽  
Gas Reservoirs ◽  
Production Time ◽  
Stable Production ◽  
Geological Conditions ◽  
Single Well ◽  
Single Production ◽  
Production Layer

AbstractFor gas reservoirs with poor physical properties, the implementation of a single well with multi-layer combined production is an effective means to achieve efficient development. However, because of the differences in the geological conditions of the vast majority of multi-layer gas reservoirs, the dynamic characteristics of the gas wells will be complex under the multi-layer combined mining mode, and the inevitable interlayer interference in the production process will affect the development effect. In this paper, the coal seam and the dense layer are opened for production at the same time. The two kinds of different types of production are not only restricted by the heterogeneity of each layer, but also the special development mode of the coal seam. Through analyzing and summarizing the productivity equation of two kinds of production layers and the characteristics of the change of production pressure, the coupling calculation is carried out by the iterative programming of node analysis method in the wellbore, which can dynamically predict the dynamic gas production. In comparison with the dynamic gas production dynamics of combined production and the overlay production of each production layer, it is found that the amount of accumulated gas production of multiple production layers in the forecast period is only 2.56% lower than that of the single production of the multi-production layer, but the investment cost of the single well multi-layer production is far lower than that of the single production, and the stable production time of the combined production is longer, indicating that the stable production time is longer.

scholarly journals Study on Borehole Arrangement Methods for Gas Extraction by Hydraulic Slotting in Long-Distance Through-Coal Seam Tunnel

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Cunfang Zhu ◽  
Shuang Cai
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Simulation Models ◽  
Gas Production ◽  
Gas Extraction ◽  
Long Distance ◽  
Pressure Relief ◽  
Coal Deposits ◽  
Geological Conditions ◽  
Rapid Pressure

How to quickly eliminate outburst in long-distance through-coal seam tunnels is one of the major challenges faced by the tunnel industry in mountainous areas. Compared with coal mine rock crosscut coal uncovering, the work surrounding the rock of through-coal seam tunnels has a high degree of breakage, large cross-section of coal uncovering, and tight time and space. In this paper, a method of networked slotting in long-distance through-coal seam tunnels for rapid pressure relief and outburst elimination is proposed. Based on this method, the corresponding mathematical governing equations and numerical simulation models have been established. The optimal borehole arrangement spacing and the slot arrangement spacing obtained by numerical optimization are 2.85 m and 3.1 m, respectively. Field gas production data of through-coal seam tunnels show that compared with the traditional dense-borehole gas extraction, the method of networked slotting in long-distance through-coal seam tunnels for rapid pressure relief and outburst elimination can shorten the extraction time by about 66%, the net quantity of peak extraction is increased by 3.55 times, and the total quantity of gas extraction when reaching the outburst prevention index is increased by 1.26 times, which verifies the feasibility of this method and the reliability of numerical simulation results. This study could be used as a valuable example for other coal deposits being mined under similar geological conditions.

Productivity Evaluation Study of Shale Gas Reservoirs

2014 ◽  
Vol 1073-1076 ◽  
pp. 2296-2299
Author(s):  
Peng Xiang Diwu ◽  
Rui Liu ◽  
Tong Jing Liu ◽  
Bin Jia
Keyword(s):  
Pressure Gradient ◽  
Shale Gas ◽  
Production Capacity ◽  
Flow Characteristics ◽  
Evaluation Study ◽  
Gas Production ◽  
Gas Reservoirs ◽  
Compression Factor ◽  
Shale Gas Reservoirs ◽  
Stable Production

The seepage mechanism of unconventional gas is very complex, and has a unique seepage mechanism and dynamic flow characteristics. It is difficult to use conventional gas production capacity to predict recoverable reserves. In this paper, starting from fluid mechanics, based on reservoir characteristics of the shale gas fracturing, a composite model of shale gas reservoirs was established, and stable production time was determined. We analyzed the effects of inside and outside zone permeability, the radius, pressure gradient, desorption influence of the compression factor and reservoir thickness, etc., and the established a shale gas well productivity equation refer to Vogel equation. The results show that: area permeability, penetration outside the area, zone radius, reservoir thickness and desorption compression factor were sensitive to shale gas production capacity; skin factor and the pressure gradient is not sensitive factor; through reliability analysis, the productivity formula which was referred to Vogel equation can determine the production capacity of shale gas wells quickly and accurately.

Vertical gas migration associated with coal seam gas production

2016 ◽  
Vol 56 (2) ◽  
pp. 602
Author(s):  
Ludovic Ricard ◽  
Julian Strand
Keyword(s):  
Coal Seam ◽  
Risk Evaluation ◽  
Critical Role ◽  
Gas Production ◽  
Mitigation Strategies ◽  
Gas Migration ◽  
Coal Seam Gas ◽  
Gas Reservoirs ◽  
Gas Leakage ◽  
Migration Pathways

Gas migration outside coal seam gas reservoirs has been identified as a risk associated with CSG production. While such an event has not been reported or scientifically associated with CSG production, understanding the physical mechanism of the vertical migration in the overburden involved should gas leakage occur would improve mitigation strategies and risk evaluation. In this extended abstract, a series of key modelling scenarios of gas migration above the reservoir are developed. Interpretation of the scenarios highlights that: the seal/leakage nature of the overburden strongly impacts gas migration and volume of gas leaked; when leakage does occur, the leaked volume represents a very small portion of the original gas in place and volume of gas produced; the connectivity of the overburden plays a critical role on the gas migration pathways and volume of gas leaked; and, residual gas saturation, and relative permeability hysteresis provide means to trap the mobile gas, significantly reducing the volume of gas leaked reaching shallower formations.

scholarly journals Tight carbonate gas well deliverability evaluation and reasonable production proration analysis

2021 ◽  
Author(s):  
Jiang Li ◽  
Xianchao Chen ◽  
Ping Gao ◽  
Jingchao Zhou
Keyword(s):  
Numerical Model ◽  
Stress Sensitivity ◽  
Gas Production ◽  
Productivity Index ◽  
Dual Porosity ◽  
Gas Reservoirs ◽  
Gas Well ◽  
Well Production ◽  
Tight Carbonate ◽  
Single Well

AbstractIt is very important to accurately predict the gas well productivity and reasonably allocate the gas production at the early development stage of gas reservoirs. However, both the non-Darcy and stress sensitivity effects have not been investigated in dual-porosity model of tight carbonate gas reservoirs. This paper proposed a new dual-porosity binomial deliverability model and single-well production proration numerical model, which consider the effects of non-Darcy and stress sensitivity. The field gas well deliverability tests data validated the accuracy of the new analytical model, which is a very helpful deliverability method when lacking deliverability test. A geological model was built on the results of the well log, well testing, and well production analysis. Then, a reasonable production proration analysis was conducted based on history matched single-well numerical model. The gas productivity index curve and production–prediction of MX22 several simulation cases were adopted to analyze the reasonable production proration. The results indicate that 1/6 may be suitable for high productivity gas well proration. In addition, the absolute open flow rate from the numerical simulation is higher than that from the new deliverability equation, which also shows that the pressure transient analysis sometimes has some deviation in formation property prediction. It is suggested comprehensively utilizing the analytical binomial model and the single-well numerical model in tight carbonate gas well deliverability evaluation.

Optimization Proration Research in Volcanic Reservoir in Songnan Gas Field

2012 ◽  
Vol 616-618 ◽  
pp. 858-863
Author(s):  
Hua Liu ◽  
Zhi Liang Shi ◽  
Xiang Fang Li ◽  
Yun Cong Gao
Keyword(s):  
Production Method ◽  
Gas Production ◽  
Production Optimization ◽  
Gas Field ◽  
Field Development ◽  
Volcanic Reservoir ◽  
Geological Conditions ◽  
High Efficient ◽  
Single Well ◽  
Line Technology

Volcanic Reservoir in Songnan gas field is now in the early development, the scale of the single well and stable development put forward important requirements, reasonable match is efficient in gas reservoir development of the key. According to the geological conditions of volcanic rock reservoirs special, in the full analysis of the dynamic and static data, and on the basis of preliminary mastered the gas, water relations; And the use of gas production method, the method of curve, economic boundary method and the improvement of horizontal Wells method of the gas line technology reasonable production optimization and argument, high efficient and economical for gas field development.

Prediction and management of solids production in typical Surat Basin coal seam gas reservoirs, eastern Australia

2015 ◽  
Vol 55 (2) ◽  
pp. 444
Author(s):  
Abbas Khaksar ◽  
Morteza Jami ◽  
Ahmadreza Younessi
Keyword(s):  
Coal Seam ◽  
Water Saturation ◽  
Gas Production ◽  
Control Measures ◽  
Coal Seam Gas ◽  
Gas Reservoirs ◽  
Short Life Span ◽  
Sand Control ◽  
Eastern Australia ◽  
Different Characteristics

The exploiting of coal seam gas (CSG) reservoirs worldwide has developed rapidly. These reservoirs are located in different geological settings and have different characteristics. In eastern Australia for instance, Surat Basin CSG reservoirs are typically thin and interbedded with thick layers of sandstone, siltstones and shales, and occur at shallow depths, adjacent to fresh-water aquifers. For commercial gas production from wet- and low- permeability thin CSG reservoirs, both the hydrostatic pressure and the water saturation have to be reduced through a de-watering and pressure depletion process. These mechanisms increase the risk of rock failure and solids production before or from the onset of gas production in many CSG wells. In thinly bedded CSG reservoirs, solids production from coals may not be a concern, but sanding from interbed rocks—some with abundant water sensitive clay minerals—may be a significant source of solids production. Given the relatively low drilling and completion costs and short life span of the CSG wells, many of the conventional sand control measures such as screens or gravel packs may be of limited use or not applicable. In this extended abstract, examples of solids production issues and the potential sources of solids in typical Surat Basin CSG wells are shown, and options for solids control are discussed.

Determing the Reasonable Single-Well Proration in Gas Reservoir by the Method of Dynamic Production

2012 ◽  
Vol 204-208 ◽  
pp. 297-302
Author(s):  
Kui Zhang ◽  
Hai Tao Li ◽  
Yang Fan Zhou ◽  
Ai Hua Li
Keyword(s):  
Low Permeability ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Field ◽  
Gas Well ◽  
High Productivity ◽  
Well Production ◽  
Stable Production ◽  
Single Well

Low permeability, low abundance, water-bearing gas reservoirs are widely distributed in China, and their reserves constitute 85% of all kinds of reservoirs in current. It has important realistic meanings to develop them. Determining of reasonable gas well production is the prerequisite to achieving long-term high productivity and stable production. This paper takes Shanggu gas field at Sulige Gas Field for example, respectively from the dynamic data analogy methods, the pressure drop rate statistical methods, gas curve methods, production system nodal analysis methods, and studied the reasonable capacity of the low permeability gas reservoir. Through comprehensive analysis，the comprehensive technical indexes about single well reasonable production was determined.

scholarly journals A numerical simulation on coal seam gas recovery from high temperature reservoir

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 3971-3978
Author(s):  
Teng Teng ◽  
Xiao-Yan Zhu ◽  
Xiang-Yang Zhang ◽  
Peng-Fei Chen ◽  
Yu-Ming Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Coal Seam ◽  
Mechanical Model ◽  
Gas Flow ◽  
Gas Production ◽  
Coal Seam Gas ◽  
Production Time ◽  
Gas Recovery ◽  
Coal Deformation ◽  
Fully Coupled

The coal seam gas recovery in deep reservoirs often meets high temperature. The change of temperature can greatly influence gas sorption, and couples heat transfer with coal deformation and gas-flow. This paper modifies the conventional Langmuir adsorption equation into a non-isothermal adsorption equation with a set of experimental data. After then, a fully coupled thermo-hydro-mechanical model of coal deformation, gas-flow and heat transfer is established. By using a finite element approach of COMSOL multi-physics, a numerical simulation of coal seam gas recovery from high temperature reservoir is subsequently implemented. The results show that the gas pressure and temperature decrease with production time and increase with the distance from production well, the reservoir permeability decreases with production time due to the compaction of increasing effective stress to coal fracture network, the cumulative gas production increases with production time exponentially whereas the production efficiency decreases negative exponentially, that the gas production in earlier 10 years accounts for 80% of the total production in 30 years. Our fully coupled thermo-hydro-mechanical model can improve the current understanding of coal seam gas recovery from high temperature reservoirs.

Hydraulic fractures productivity performance in tight gas sands—a numerical simulation approach

2011 ◽  
Vol 51 (1) ◽  
pp. 519
Author(s):  
Jakov Ostojic ◽  
Reza Rezaee ◽  
Hassan Bahrami
Keyword(s):  
Hydraulic Fracture ◽  
Effective Field ◽  
Gas Production ◽  
Simulation Software ◽  
Hydraulic Fractures ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Gas Recovery ◽  
Single Well ◽  
The Impact

The increasing global demand for energy along with the reduction in conventional gas reserves has lead to the increasing demand and exploration of unconventional gas sources. Hydraulically-fractured tight gas reservoirs are one of the most common unconventional sources being produced today and look to be a regular source of gas in the future. Hydraulic fracture orientation and spacing are important factors in effective field drainage and gas recovery. This paper presents a 3D single well hydraulically fractured tight gas model created using commercial simulation software, which will be used to simulate gas production and synthetically generate welltest data. The hydraulic fractures will be simulated with varying sizes and different numbers of fractures intersecting the wellbore. The focus of the simulation runs will be on the effect of hydraulic fracture size and spacing on well productivity performance. The results obtained from the welltest simulations will be plotted and used to understand the impact on reservoir response under the different hydraulic fracturing scenarios. The outputs of the models can also be used to relate welltest response to the efficiency of hydraulic fractures and, therefore, productivity performance.

scholarly journals A Comprehensive Coal Reservoir Classification Method Base on Permeability Dynamic Change and Its Application

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 644 ◽  
Author(s):  
Xinlu Yan ◽  
Songhang Zhang ◽  
Shuheng Tang ◽  
Zhongcheng Li ◽  
Yongxiang Yi ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Dynamic Change ◽  
Initial Permeability ◽  
Gas Production ◽  
Gas Desorption ◽  
Reservoir Permeability ◽  
Geological Conditions ◽  
Production Stages ◽  
Productivity Potential ◽  
Coal Reservoir

Due to the unique adsorption and desorption characteristics of coal, coal reservoir permeability changes dynamically during coalbed methane (CBM) development. Coal reservoirs can be classified using a permeability dynamic characterization in different production stages. In the single-phase water flow stage, four demarcating pressures are defined based on the damage from the effective stress on reservoir permeability. Coal reservoirs are classified into vulnerable, alleviative, and invulnerable reservoirs. In the gas desorption stage, two demarcating pressures are used to quantitatively characterize the recovery properties of permeability based on the recovery effect of the matrix shrinkage on permeability, namely the rebound pressure (the pressure corresponding to the lowest permeability) and recovery pressure (the pressure when permeability returns to initial permeability). Coal reservoirs are further classified into recoverable and unrecoverable reservoirs. The physical properties and influencing factors of these demarcating pressures are analyzed. Twenty-six wells from the Shizhuangnan Block in the southern Qinshui Basin of China were examined as a case study, showing that there is a significant correspondence between coal reservoir types and CBM well gas production. This study is helpful for identifying geological conditions of coal reservoirs as well as the productivity potential of CBM wells.

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