scholarly journals Numerical Simulation Study on Seepage Theory of a Multi-Section Fractured Horizontal Well in Shale Gas Reservoirs Based on Multi-Scale Flow Mechanisms

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2329 ◽  
Author(s):  
Chao Tang ◽  
Xiaofan Chen ◽  
Zhimin Du ◽  
Ping Yue ◽  
Jiabao Wei
Keyword(s):  
Shale Gas ◽  
Large Scale ◽  
Gas Diffusion ◽  
Gas Production ◽  
Hydraulic Fractures ◽  
Klinkenberg Effect ◽  
Stimulated Reservoir Volume ◽  
Multi Scale ◽  
Reservoir Volume ◽  
Flow Mechanisms

Aimed at the multi-scale fractures for stimulated reservoir volume (SRV)-fractured horizontal wells in shale gas reservoirs, a mathematical model of unsteady seepage is established, which considers the characteristics of a dual media of matrix and natural fractures as well as flow in the large-scale hydraulic fractures, based on a discrete-fracture model. Multi-scale flow mechanisms, such as gas desorption, the Klinkenberg effect, and gas diffusion are taken into consideration. A three-dimensional numerical model based on the finite volume method is established, which includes the construction of spatial discretization, calculation of average pressure gradient, and variable at interface, etc. Some related processing techniques, such as boundedness processing upstream and downstream of grid flow, was used to limit non-physical oscillation at large-scale hydraulic fracture interfaces. The sequential solution is performed to solve the pressure equations of matrix, natural, and large-scale hydraulic fractures. The production dynamics and pressure distribution of a multi-section fractured horizontal well in a shale gas reservoir are calculated. Results indicate that, with the increase of the Langmuir volume, the average formation pressure decreases at a slow rate. Simultaneously, the initial gas production and the contribution ratio of the desorbed gas increase. With the decrease of the pore size of the matrix, gas diffusion and the Klinkenberg effect have a greater impact on shale gas production. By changing the fracture half-length and the number of fractured sections, we observe that the production process can not only pursue the long fractures or increase the number of fractured sections, but also should optimize the parameters such as the perforation position, cluster spacing, and fracturing sequence. The stimulated reservoir volume can effectively control the shale reservoir.

Hydraulic Fractures Simulation and Stimulated Reservoir Volume Estimation for Shale Gas Fracturing

2019 ◽  
Author(s):  
Ran Lin ◽  
Lan Ren ◽  
Jinzhou Zhao ◽  
Yongfu Tao ◽  
Xiucheng Tan ◽  
...  
Keyword(s):  
Shale Gas ◽  
Volume Estimation ◽  
Hydraulic Fractures ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume

Quad-porosity shale systems – a review

2016 ◽  
Vol 13 (6) ◽  
pp. 529-539 ◽  
Author(s):  
Samarth D. Patwardhan ◽  
Fatemeh Famoori ◽  
Suresh Kumar Govindarajan
Keyword(s):  
Shale Gas ◽  
Experimental Studies ◽  
Gas Diffusion ◽  
Gas Production ◽  
Total Production ◽  
Actual Process ◽  
Coupled Flow ◽  
Production Forecast ◽  
Content Type ◽  
Flow Mechanisms

Purpose This paper aims to review the quad-porosity shale system from a production standpoint. Understanding the complex but coupled flow mechanisms in such reservoirs is essential to design appropriate completions and further, optimally produce them. Dual-porosity and dual permeability models are most commonly used to describe a typical shale gas reservoir. Design/methodology/approach Characterization of such reservoirs with extremely low permeability does not aptly capture the physics and complexities of gas storage and flow through their existing nanopores. This paper reviews the methods and experimental studies used to describe the flow mechanisms of gas through such systems, and critically recommends the direction in which this work could be extended. A quad-porosity shale system is defined not just as porosity in the matrix and fracture, but as a combination of multiple porosity values. Findings It has been observed from studies conducted that shale gas production modeled with conventional simulator/model is seen to be much lower than actually observed in field data. This paper reviews the various flow mechanisms in shale nanopores by capturing the physics behind the actual process. The contribution of Knudson diffusion and gas slippage, gas desorption and gas diffusion from Kerogen to total production is studied in detail. Originality/value The results observed from experimental studies and simulation runs indicate that the above effects should be considered while modeling and making production forecast for such reservoirs.

scholarly journals Numerical Analysis of Transient Pressure Behaviors with Shale Gas MFHWs Interference

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 262 ◽  
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.

History Matching of Stimulated Reservoir Volume of Shale-Gas Reservoirs Using an Iterative Ensemble Smoother

SPE Journal ◽  
2017 ◽  
Vol 23 (02) ◽  
pp. 346-366 ◽  
Author(s):  
Haibin Chang ◽  
Dongxiao Zhang
Keyword(s):  
Hydraulic Fracturing ◽  
Shale Gas ◽  
History Matching ◽  
Fracture Network ◽  
Hydraulic Fractures ◽  
Gas Reservoirs ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Shale Gas Reservoirs ◽  
Iterative Ensemble Smoother

Summary Economic production from shale-gas reservoirs typically relies on the drilling of horizontal wells and hydraulic fracturing in multiple stages. In addition to the creation of hydraulic fractures, hydraulic-fracturing treatment can also reopen existing natural fractures, which can create a complex-fracture network. The area that is covered by the fracture network is usually termed the stimulated reservoir volume (SRV), and the spatial extent and properties of the SRV are crucial for shale-gas-production behavior. In this work, we propose a method for history matching of the SRV of shale-gas reservoirs using production data. For each hydraulic-fracturing stage, the fracture network is parameterized with one major fracture of the hydraulic fractures and the SRV that represents minor hydraulic fractures and reopened natural fractures. The major fracture is modeled explicitly, whereas the SRV is modeled by the dual-permeability/dual-porosity (DP/DP) model. Moreover, the spatial extent of the SRV is parameterized by the level-set-function values on a predefined representing-node system. After parameterization, an iterative ensemble smoother is used to perform history matching. Both single-stage-fracturing cases and multistage-fracturing cases are set up to test the performance of the proposed method. Numerical results demonstrate that by use of the proposed method, the SRV can be well-recognized by assimilating production data.

Diffusion and Flow Mechanisms of Shale Gas through Matrix Pores and Gas Production Forecasting

2013 ◽  
Author(s):  
Juntai Shi ◽  
Lei Zhang ◽  
Yuansheng Li ◽  
Wei Yu ◽  
Xiangnan He ◽  
...  
Keyword(s):  
Shale Gas ◽  
Gas Production ◽  
Production Forecasting ◽  
Flow Mechanisms

scholarly journals APPLICATION OF FRACTAL GEOMETRY IN EVALUATION OF EFFECTIVE STIMULATED RESERVOIR VOLUME IN SHALE GAS RESERVOIRS

Fractals ◽  
2017 ◽  
Vol 25 (04) ◽  
pp. 1740007 ◽  
Author(s):  
GUANGLONG SHENG ◽  
YULIANG SU ◽  
WENDONG WANG ◽  
FARZAM JAVADPOUR ◽  
MEIRONG TANG
Keyword(s):  
Hydraulic Fracturing ◽  
Shale Gas ◽  
Fractal Geometry ◽  
Fracture Network ◽  
Gas Reservoirs ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Adsorbed Gas ◽  
Shale Gas Reservoirs ◽  
Shale Reservoirs

According to hydraulic-fracturing practices conducted in shale reservoirs, effective stimulated reservoir volume (ESRV) significantly affects the production of hydraulic fractured well. Therefore, estimating ESRV is an important prerequisite for confirming the success of hydraulic fracturing and predicting the production of hydraulic fracturing wells in shale reservoirs. However, ESRV calculation remains a longstanding challenge in hydraulic-fracturing operation. In considering fractal characteristics of the fracture network in stimulated reservoir volume (SRV), this paper introduces a fractal random-fracture-network algorithm for converting the microseismic data into fractal geometry. Five key parameters, including bifurcation direction, generating length ([Formula: see text]), deviation angle ([Formula: see text]), iteration times ([Formula: see text]) and generating rules, are proposed to quantitatively characterize fracture geometry. Furthermore, we introduce an orthogonal-fractures coupled dual-porosity-media representation elementary volume (REV) flow model to predict the volumetric flux of gas in shale reservoirs. On the basis of the migration of adsorbed gas in porous kerogen of REV with different fracture spaces, an ESRV criterion for shale reservoirs with SRV is proposed. Eventually, combining the ESRV criterion and fractal characteristic of a fracture network, we propose a new approach for evaluating ESRV in shale reservoirs. The approach has been used in the Eagle Ford shale gas reservoir, and results show that the fracture space has a measurable influence on migration of adsorbed gas. The fracture network can contribute to enhancement of the absorbed gas recovery ratio when the fracture space is less than 0.2 m. ESRV is evaluated in this paper, and results indicate that the ESRV accounts for 27.87% of the total SRV in shale gas reservoirs. This work is important and timely for evaluating fracturing effect and predicting production of hydraulic fracturing wells in shale reservoirs.

Stimulated reservoir volume estimation for shale gas fracturing: Mechanism and modeling approach

2018 ◽  
Vol 166 ◽  
pp. 290-304 ◽  
Author(s):  
Lan Ren ◽  
Ran Lin ◽  
Jinzhou Zhao ◽  
Vamegh Rasouli ◽  
Jiangyu Zhao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Volume Estimation ◽  
Stimulated Reservoir Volume ◽  
Modeling Approach ◽  
Reservoir Volume ◽  
Fracturing Mechanism
Sign in / Sign up

Export Citation Format

Share Document