The impact of kerogen properties on shale gas production: A reservoir simulation sensitivity analysis

Shale gas is one of the primary types of unconventional reservoirs to be exploited in search for long-lasting resources. Production from shale gas reservoirs requires horizontal drilling with hydraulic fracturing to achieve the most economic production. However, plenty of parameters (e.g., fracture conductivity, fracture spacing, half-length, matrix permeability, and porosity,etc) have high uncertainty that may cause unexpected high cost. Therefore, to develop an efficient and practical method for quantifying uncertainty and optimizing shale-gas production is highly desirable. This paper focuses on analyzing the main factors during gas production, including petro-physical parameters, hydraulic fracture parameters, and work conditions on shale-gas production performances. Firstly, numerous key parameters of shale-gas production from the fourteen best-known shale gas reservoirs in the United States are selected through the correlation analysis. Secondly, a grey relational grade method is used to quantitatively estimate the potential of developing target shale gas reservoirs as well as the impact ranking of these factors. Analyses on production data of many shale-gas reservoirs indicate that the recovery efficiencies are highly correlated with the major parameters predicted by the new method. Among all main factors, the impact ranking of major factors, from more important to less important, is matrix permeability, fracture conductivity, fracture density of hydraulic fracturing, reservoir pressure, total organic content (TOC), fracture half-length, adsorbed gas, reservoir thickness, reservoir depth, and clay content. This work can provide significant insights into quantifying the evaluation of the development potential of shale gas reservoirs, the influence degree of main factors, and optimization of shale gas production.

Download Full-text

Numerical Simulation of Shale Gas Multiscale Seepage Mechanism-Coupled Stress Sensitivity

Journal of Chemistry ◽

10.1155/2019/7387234 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Xun Yan ◽

Jing Sun ◽

Dehua Liu

Keyword(s):

Shale Gas ◽

Gas Flow ◽

Gas Transport ◽

Sensitivity Coefficient ◽

Stress Sensitivity ◽

Gas Production ◽

Molecular Flow ◽

Adsorption Phenomenon ◽

Gas Seepage ◽

The Impact

The complexity of the gas transport mechanism in microfractures and nanopores is caused by the feature of multiscale and multiphysics. Figuring out the flow mechanism is of great significance for the efficient development of shale gas. In this paper, an apparent permeability model which covers continue, slip, transition, and molecular flow and geomechanical effect was presented. Additionally, a mathematical model comprising multiscale, geomechanics, and adsorption phenomenon was proposed to characterize gas flow in the shale reservoir. The aim of this paper is to investigate some important impacts in the process of gas transportation, which includes the shale stress sensitivity, adsorption phenomenon, and reservoir porosity. The results reveal that the performance of the multistage fractured horizontal well is strongly influenced by stress sensitivity coefficient. The cumulative gas production will decrease sharply when the shale gas reservoir stress sensitivity coefficient increases. In addition, the adsorption phenomenon has an influence on shale gas seepage and sorption capacity; however, the effect of adsorption is very weak in the early gas transport period, and the impact of later will increase. Moreover, shale porosity also greatly affects the shale gas transportation.

Download Full-text

Understanding Shale Gas Production Mechanisms Through Reservoir Simulation

10.2118/167753-ms ◽

2014 ◽

Cited By ~ 5

Author(s):

Hao Sun ◽

Adwait Chawathe ◽

Hussein Hoteit ◽

Xundan Shi ◽

Lin Li

Keyword(s):

Shale Gas ◽

Reservoir Simulation ◽

Gas Production ◽

Production Mechanisms

Download Full-text

An Analytical Flow Model for Heterogeneous Multi-Fractured Systems in Shale Gas Reservoirs

Energies ◽

10.3390/en11123422 ◽

2018 ◽

Vol 11 (12) ◽

pp. 3422 ◽

Cited By ~ 4

Author(s):

Honghua Tao ◽

Liehui Zhang ◽

Qiguo Liu ◽

Qi Deng ◽

Man Luo ◽

...

Keyword(s):

Fractal Dimension ◽

Anomalous Diffusion ◽

Shale Gas ◽

Gas Production ◽

Gas Reservoirs ◽

Pressure Transient ◽

Mass Fractal ◽

Shale Gas Reservoirs ◽

Mass Fractal Dimension ◽

The Impact

The use of multiple hydraulically fractured horizontal wells has been proven to be an efficient and effective way to enable shale gas production. Meanwhile, analytical models represent a rapid evaluation method that has been developed to investigate the pressure-transient behaviors in shale gas reservoirs. Furthermore, fractal-anomalous diffusion, which describes a sub-diffusion process by a non-linear relationship with time and cannot be represented by Darcy’s law, has been noticed in heterogeneous porous media. In order to describe the pressure-transient behaviors in shale gas reservoirs more accurately, an improved analytical model based on the fractal-anomalous diffusion is established. Various diffusions in the shale matrix, pressure-dependent permeability, fractal geometry features, and anomalous diffusion in the stimulated reservoir volume region are considered. Type curves of pressure and pressure derivatives are plotted, and the effects of anomalous diffusion and mass fractal dimension are investigated in a sensitivity analysis. The impact of anomalous diffusion is recognized as two opposite aspects in the early linear flow regime and after that period, when it changes from 1 to 0.75. The smaller mass fractal dimension, which changes from 2 to 1.8, results in more pressure and a drop in the pressure derivative.

Download Full-text

Numerical Analysis of Transient Pressure Behaviors with Shale Gas MFHWs Interference

Energies ◽

10.3390/en12020262 ◽

2019 ◽

Vol 12 (2) ◽

pp. 262 ◽

Cited By ~ 4

Author(s):

Dapeng Gao ◽

Yuewu Liu ◽

Daigang Wang ◽

Guofeng Han

Keyword(s):

Shale Gas ◽

Large Scale ◽

Horizontal Well ◽

Gas Production ◽

Pressure Recovery ◽

Hydraulic Fractures ◽

Transient Pressure ◽

Gas Well ◽

Well Pattern ◽

The Impact

After the large-scale horizontal well pattern development in shale gas fields, the problem of fast pressure drop and gas well abandonment caused by well interference becomes more serious. It is urgent to understand the downhole transient pressure and flow characteristics of multi-stage fracturing horizontal well (MFHW) with interference. Therefore, the reservoir around the MFHW is divided into three regions: fracturing fracture, Stimulated reservoir volume (SRV), and unmodified matrix. Then, multi-region coupled flow model is established according to reservoir physical property and flow mechanism of each part. The model is numerically solved using the perpendicular bisection (PEBI) grids and the finite volume method. The accuracy of the model is verified by analyzing the measured pressure recovery data of one practical shale gas well and fitting the monitoring data of the later production pressure. Finally, this model is used to analyze the effects of factors, such as hydraulic fractures’ connectivity, well distance, the number of neighboring wells and well pattern arrangement, on the transient pressure and seepage characteristics of the well. The study shows that the pressure recovery double logarithmic curves fall in later part when the well is disturbed by a neighboring production well. The earlier and more severe the interference, the sooner the curve falls off and the larger the amplitude shows. If the well distance is closer, and if there are more neighboring wells and interconnected corresponding fracturing segments, the more severe interference appears among the wells. Moreover, the well interference may still exist even without interlinked fractures or SRV. Especially, severe interference will affect production when the hydraulic fractures are connected directly, and the interference is weaker when only SRV induced fracture network combined between wells, which is beneficial to production sometimes. When severe well interference occurs, periodic well shut-in is needed to help restore the reservoir pressure and output capacity. In the meanwhile, the daily output should be controlled reasonably to prolong the stable production time. This research will help to understand the impact of well interference to gas production, and to optimize the well spacing and achieve satisfied performance.

Download Full-text

Key Factors in Shale Gas Modeling and Simulation

Archives of Mining Sciences ◽

10.2478/amsc-2014-0068 ◽

2014 ◽

Vol 59 (4) ◽

pp. 987-1004 ◽

Cited By ~ 2

Author(s):

Łukasz Klimkowski ◽

Stanisław Nagy

Keyword(s):

Shale Gas ◽

Gas Production ◽

Production Performance ◽

Hydraulic Fractures ◽

Well Performance ◽

Key Factors ◽

Gas Well ◽

Well Production ◽

Multi Stage ◽

The Impact

Abstract Multi-stage hydraulic fracturing is the method for unlocking shale gas resources and maximizing horizontal well performance. Modeling the effects of stimulation and fluid flow in a medium with extremely low permeability is significantly different from modeling conventional deposits. Due to the complexity of the subject, a significant number of parameters can affect the production performance. For a better understanding of the specifics of unconventional resources it is necessary to determine the effect of various parameters on the gas production process and identification of parameters of major importance. As a result, it may help in designing more effective way to provide gas resources from shale rocks. Within the framework of this study a sensitivity analysis of the numerical model of shale gas reservoir, built based on the latest solutions used in industrial reservoir simulators, was performed. The impact of different reservoir and hydraulic fractures parameters on a horizontal shale gas well production performance was assessed and key factors were determined.

Download Full-text

Integrated Approach to Drilling Project in Unconventional Reservoir Using Reservoir Simulation

E3S Web of Conferences ◽

10.1051/e3sconf/20183501002 ◽

2018 ◽

Vol 35 ◽

pp. 01002

Author(s):

Jerzy Stopa ◽

Rafał Wiśniowski ◽

Paweł Wojnarowski ◽

Damian Janiga ◽

Krzysztof Skrzypaszek

Keyword(s):

Shale Gas ◽

Reservoir Simulation ◽

Integrated Approach ◽

Gas Production ◽

Full Scale ◽

Production Optimization ◽

Unconventional Reservoir ◽

Gas Field ◽

Technical Factor ◽

Drilling Project

Accumulation and flow mechanisms in unconventional reservoir are different compared to conventional. This requires a special approach of field management with drilling and stimulation treatments as major factor for further production. Integrated approach of unconventional reservoir production optimization assumes coupling drilling project with full scale reservoir simulation for determine best well placement, well length, fracturing treatment design and mid-length distance between wells. Full scale reservoir simulation model emulate a part of polish shale – gas field. The aim of this paper is to establish influence of technical factor for gas production from shale gas field. Due to low reservoir permeability, stimulation treatment should be direct towards maximizing the hydraulic contact. On the basis of production scenarios, 15 stages hydraulic fracturing allows boost gas production over 1.5 times compared to 8 stages. Due to the possible interference of the wells, it is necessary to determine the distance between the horizontal parts of the wells trajectories. In order to determine the distance between the wells allowing to maximize recovery factor of resources in the stimulated zone, a numerical algorithm based on a dynamic model was developed and implemented. Numerical testing and comparative study show that the most favourable arrangement assumes a minimum allowable distance between the wells. This is related to the volume ratio of the drainage zone to the total volume of the stimulated zone.

Download Full-text

Coupling of fracture model with reservoir simulation to simulate shale gas production with complex fractures and nanopores

Journal of Petroleum Science and Engineering ◽

10.1016/j.petrol.2020.107422 ◽

2020 ◽

Vol 193 ◽

pp. 107422 ◽

Cited By ~ 1

Author(s):

Xincheng Wan ◽

Vamegh Rasouli ◽

Branko Damjanac ◽

Wei Yu ◽

Hongbing Xie ◽

...

Keyword(s):

Shale Gas ◽

Reservoir Simulation ◽

Gas Production ◽

Fracture Model ◽

Complex Fractures

Download Full-text

An integrated workflow to perform reservoir and completion parametric study on a shale gas reservoir

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-019-00829-9 ◽

2020 ◽

Vol 10 (4) ◽

pp. 1497-1510

Author(s):

Mohamed Mahmoud ◽

Ahmed Aleid ◽

Abdulwahab Ali ◽

Muhammad Shahzad Kamal

Keyword(s):

Shale Gas ◽

Gas Production ◽

Production Performance ◽

Analytical Models ◽

Well Performance ◽

Short Term ◽

Gas Reservoirs ◽

Shale Gas Reservoirs ◽

The Impact

AbstractThe main objectives of this paper are to assess the long-term and short-term production based on both reservoir parameters and completion parameters of shale gas reservoirs. The effects of the reservoir parameters (permeability and the initial reservoir pressure) and completion parameters (fracture geometry, stimulated reservoir volume, etc.) on the short-term and long-term production of shale gas reservoirs were investigated. The currently used approach relies mainly on the decline curve analysis or analogs from a similar shale play to forecast the gas production from shale gas reservoirs. Both these approaches are not satisfactory because they are calibrated on short production history and do not assess the impact of uncertainty in reservoir and well data. For the first time, this study integrates initial production analysis, probabilistic evaluation, and sensitivity analysis to develop a robust workflow that will help in designing a sustainable production from shale gas plays. The reservoir and completion parameters were collected from different available resources, and the probability distributions of gathered uncertain data were defined. Then analytical models were used to forecast the production. Two well evaluation results are presented in this paper. Based on the results, completion parameters affected the short-term and long-term production, while the reservoir parameters controlled the long-term production. Long-term well performance was mainly controlled by the fracture half-length and fracture height, whereas other completion and reservoir parameters have an insignificant effect. Stimulation treatment design defines the initial well performance, while well placement decision defines well long-term performance. The findings of this study would help in better understanding the production performance of shale gas reservoirs, maximizing production by selecting effective completion parameters and considering the governing reservoir parameters. Moreover, it would help in accomplishing more effective stimulation treatments and define the potentiality of the basin.

Download Full-text