scholarly journals THE IMPACT OF THE PRODUCTION OF NEIGHBOUR WELLS ON WELL PRODUCTIVITY IN A SHALE GAS RESERVOIR

2014 ◽  
Vol 15 (1) ◽  
Author(s):  
Asri Nugrahanti ◽  
Agus Guntoro ◽  
Muhammad Taufiq Fathaddin ◽  
Denny Suwanda Djohor
Keyword(s):  
Shale Gas ◽  
Recovery Factor ◽  
Gas Reservoir ◽  
Gas Recovery ◽  
Shale Gas Reservoir ◽  
Matrix Permeability ◽  
Well Spacing ◽  
Influence Parameter ◽  
The Impact ◽  
Half Length

ABSTRACT: A shale gas reservoir is a self-contained source-reservoir system, characterized by extremely low matrix-permeability and low porosity, which typically requires extensive fracturing to produce gas at commercial rates. This paper presents a simulation experiment, intended to study the impact of well interference on gas recovery in a shale gas reservoir. The simulation model was constructed to study well interference through variation of horizontal well length, fracture half length, number of fracture, and well spacing. The results show that the increment of recovery factor of a well in the presence of neighbour wells is up to 7%. In this study, fracture half length is the most influence parameter on recovery factor, initial rate and reservoir pressure decline. ABSTRAK: Takungan gas syal merupakan sistem sumber-takungan kandung sendiri, khasnya kerana ia mempunyai kebolehtelapan-matriks yang begitu rendah dan keliangan yang rendah.  Sifat sebegini memerlukan ia melalui peretakan yang ekstensif untuk menghasilkan gas pada nilai komersial. Kertas kerja ini membentangkan eksperimen simulasi yang bertujuan untuk mengkaji impak perigi interferens terhadap perolehan gas dalam takungan gas syal.  Model simulasi di konstruksi untuk mengkaji interferens perigi; iaitu menerusi pelbagai variasi  panjang mendatar perigi, retakan separuh panjang dan jarak perigi.  Keputusan menunjukkan peningkatan faktor perolehan perigi sebanyak 7% dengan kehadiran perigi bersebelahan. Dalam kajian ini, retakan separuh panjang merupakan ciri utama dalam faktor perolehan, kadar awalan dan penurunan tekanan takungan.

scholarly journals Investigation of the Main Factors During Shale-gas Production Using Grey Relational Analysis

2016 ◽  
Vol 9 (1) ◽  
pp. 207-215 ◽  
Author(s):  
Hongling Zhang ◽  
Jing Wang ◽  
Haiyong Zhang
Keyword(s):  
Shale Gas ◽  
Gas Production ◽  
Gas Reservoirs ◽  
Fracture Conductivity ◽  
Matrix Permeability ◽  
Shale Gas Reservoirs ◽  
Main Factors ◽  
Grey Relational ◽  
The Impact ◽  
Half Length

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.

Investigation of CO2–CH4 Displacement and Transport in Shale for Enhanced Shale Gas Recovery and CO2 Sequestration

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Xi-Dong Du ◽  
Min Gu ◽  
Shuo Duan ◽  
Xue-Fu Xian
Keyword(s):  
Shale Gas ◽  
Co2 Storage ◽  
Fixed Bed ◽  
Co2 Injection ◽  
Gas Reservoir ◽  
Co2 Gas ◽  
Gas Recovery ◽  
Shale Gas Reservoir ◽  
Shale Reservoir ◽  
Adsorption Amount

To gain a better understanding of the enhanced shale gas recovery by CO2 gas injection (CO2-ESGR) technique, the dynamic displacement mechanism of CO2–CH4, the CO2 enhanced shale gas recovery (RCH4), and CO2 storage capacity (VCO2) were studied based on transport properties of CO2 and CH4. Experiments of CO2 injection into shale gas reservoir preadsorbed by CH4 were performed in a fixed bed. Breakthrough curves were obtained under different test conditions and simulated by one-dimension advection-dispersion (AD) model. It was found that dispersion coefficient (K1) rather than molecular diffusivity of CO2 dominated its transport in shale. K1 together with advection velocity (υ) of CO2 during CH4 displacement controls RCH4 and VCO2. When transporting in shale gas reservoir, CO2 had larger dynamic adsorption amount and υ, but smaller K1 than CH4. The competitive transport and adsorption behavior of CO2 and CH4 made it possible for CO2 to store in shale reservoir and to drive the in-place CH4 out of shale reservoir. The transfer zone of CO2–CH4 displacement (CCD) was very wide. High RCH4 and VCO2 were reached at low injection CO2 gas pressure and for small shale particles. Higher injection flow rates of CO2 and temperatures ranging from 298 K to 338 K had a little effect on RCH4 and VCO2. For field conditions, high CO2 injection pressure has to be used because the pore pressure of shale reservoir and adsorption amount of CH4 increase with the increase in depth of shale gas reservoir, but RCH4 is still not high.

scholarly journals Research progress and prospects of CO2 enhanced shale gas recovery and geologic sequestration

2018 ◽  
Vol 53 ◽  
pp. 04002
Author(s):  
Rong Chen ◽  
GuoHui Zhang ◽  
ChengGao Yi
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Carbonic Acid ◽  
Research Progress ◽  
Geologic Sequestration ◽  
Affecting Factors ◽  
Gas Reservoir ◽  
Shale Formations ◽  
Gas Recovery ◽  
Shale Gas Reservoir

CO2 injection to strengthen shale gas development is a new technology to improve shale gas recovery and realize geologic sequestration. Many scholars have studied these aspects of this technology: mechanism of CO2 displacement CH4, CO2 and CH4 adsorption capacity, affecting factors of shale adsorption CO2, CO2 displacement numerical simulation, and supercritical CO2 flooding CH4 advantages. Research shows that CO2 can exchange CH4 in shale formations, improve shale gas recovery, on the other hand shale formations is suitable for CO2 sequestration because shale gas reservoir is compact. The supercritical CO2 has advantages such as large fluid diffusion coefficient, CO2 dissolution in water to form carbonic acid that can effectively improve the formation pore permeability etc., so the displacement efficiency of supercritical CO2 is high. But at present the technology study mainly focus on laboratory and numerical simulation, there is still a big gap to industrial application, need to study combined effect of influence factors, suitable CO2 injection parameter in different shale gas reservoir, CO2 injection risk and solutions etc.

Proxy-Based Assisted History Matching and Well-Spacing Optimization in Shale Gas Field

2021 ◽  
Vol 73 (04) ◽  
pp. 56-57
Author(s):  
Chris Carpenter
Keyword(s):  
Shale Gas ◽  
History Matching ◽  
Work Flow ◽  
University Of Texas ◽  
Matrix Permeability ◽  
Reservoir Volume ◽  
Well Spacing ◽  
Assisted History Matching ◽  
The University ◽  
Half Length

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 200466, “Proxy-Based Assisted History Matching and Well-Spacing Optimization in Shale Gas Development of a Real Field Case,” by Chuxi Liu, The University of Texas at Austin; Wei Yu, Sim Tech and The University of Texas at Austin; and Cheng Chang, PetroChina, et al., prepared for the 2020 SPE Improved Oil Recovery Conference, originally scheduled to be held in Tulsa, 18–22 April. The paper has not been peer reviewed. A robust, reliable work flow for well-spacing optimization in a shale reservoir development incorporating various types of uncertainties and detailed economics analysis is necessary for achieving sustainable unconventional production. In the complete paper, the authors describe a novel well-spacing-optimization work flow based on the results of assisted history matching and apply it to a real shale gas well, incorporating uncertainty parameters such as matrix permeability, matrix porosity, fracture half-length, fracture height, fracture width, fracture conductivity, and fracture water saturation. Introduction The work of well-spacing optimization is significant because it will subsequently dominate the planning of the drilling job and completion job and ultimately will affect recovery efficiency. The purpose of well-spacing optimization serves to maximize either capital revenue or ultimate recovery. The greatest challenge for well-spacing optimization is how to interpret the uncertainties associated with unconventional reservoirs. Stimulated reservoir volume and external reservoir volume, effective fracture half-length vs. propped half-length, matrix permeability, and complex structural geology are examples of such challenges. Therefore, developing an efficient and trustworthy work flow for optimizing well spacing in any shale reservoir is critical. Previous work on unconventional shale well-spacing optimization includes operator data analysis and numerical and analytical simulation. However, almost all previous studies ignored the effects of uncertainties. In addition, most studies require input information regarding the reservoir of interest. One method to obtain such information is to history match the production data, and a few history-matching methods have been explored and analyzed. Nevertheless, traditional history-matching methods could not overcome the problem of high-dimensional uncertainty space, as is commonly seen in unconventional development. Because of this, more- stochastic approaches have been developed and applied. These methods use the concept of proxy to minimize simulation runs and are also able to obtain as many, or more, history-matching realizations. Furthermore, Markov-chain Monte Carlo (MCMC) algorithms usually are coupled with the proxy model in assisted history matching. This method could be helpful in finding the complex posterior distributions of multiple uncertainty variables with ease.

scholarly journals Effect of Complex Natural Fractures on Economic Well Spacing Optimization in Shale Gas Reservoir with Gas-Water Two-Phase Flow

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2853
Author(s):  
Cheng Chang ◽  
Yongming Li ◽  
Xiaoping Li ◽  
Chuxi Liu ◽  
Mauricio Fiallos-Torres ◽  
...  
Keyword(s):  
Shale Gas ◽  
Two Phase Flow ◽  
Natural Fracture ◽  
Hydraulic Fractures ◽  
Phase Flow ◽  
Natural Fractures ◽  
Gas Reservoir ◽  
Two Phase ◽  
Shale Gas Reservoir ◽  
Well Spacing

At present, investigation of the effects of natural fractures on optimal well spacing of shale gas reservoirs from an economic perspective has been lacking. Traditional frameworks of fracture characterization, such as local grid refinement, make it unfeasible and inaccurate to study these effects of high-density natural fractures with complex geometries on well spacing. In this study, the non-intrusive EDFM (embedded discrete fracture model) method was presented to characterize fractures fast and accurately. The non-intrusiveness of EDFM removed the necessity of accessing the codes behind reservoir simulators, which meant it could simply create associated keywords that would correspondingly modify these fracture properties in separate files without information regarding the source codes. By implementing this powerful technology, a field-scale shale gas reservoir model was set up, including two-phase flow. The effective properties of hydraulic fractures were determined from the history matching process, and the results were entered into the well spacing optimization workflow. Different scenarios of natural fracture (NF) distributions and well spacing were designed, and the final economic analysis for each case was explored based on simulated productions. As a result, one of the findings of this study was that optimal well spacing tended to increase if more natural fractures were presented in the reservoir.

scholarly journals A Novel Optimization Workflow Coupling Statistics-Based Methods to Determine Optimal Well Spacing and Economics in Shale Gas Reservoir with Complex Natural Fractures

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3965
Author(s):  
Cheng Chang ◽  
Chuxi Liu ◽  
Yongming Li ◽  
Xiaoping Li ◽  
Wei Yu ◽  
...  
Keyword(s):  
Shale Gas ◽  
History Matching ◽  
Net Present Value ◽  
Hydraulic Fractures ◽  
Natural Fractures ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Shale Gas Reservoir ◽  
Shale Gas Reservoirs ◽  
Well Spacing

In order to account for big uncertainties such as well interferences, hydraulic and natural fractures’ properties and matrix properties in shale gas reservoirs, it is paramount to develop a robust and efficient approach for well spacing optimization. In this study, a novel well spacing optimization workflow is proposed and applied to a real shale gas reservoir with two-phase flow, incorporating the systematic analysis of uncertainty reservoir and fracture parameters. One hundred combinations of these uncertainties, considering their interactions, were gathered from assisted history matching solutions, which were calibrated by the actual field production history from the well in the Sichuan Basin. These combinations were used as direct input to the well spacing optimization workflow, and five “wells per section” spacing scenarios were considered, with spacing ranging from 157 m (517 ft) to 472 m (1550 ft). An embedded discrete fracture model was used to efficiently model both hydraulic fractures and complex natural fractures non-intrusively, along with a commercial compositional reservoir simulator. Economic analysis after production simulation was then carried out, by collecting cumulative gas and water production after 20 years. The net present value (NPV) distributions of the different well spacing scenarios were calculated and presented as box-plots with a NPV ranging from 15 to 35 million dollars. It was found that the well spacing that maximizes the project NPV for this study is 236 m (775 ft), with the project NPV ranging from 15 to 35 million dollars and a 50th percentile (P50) value of 25.9 million dollars. In addition, spacings of 189 m (620 ft) and 315 m (1033 ft) can also produce substantial project profits, but are relatively less satisfactory than the 236 m (775 ft) case when comparing the P25, P50 and P75 values. The results obtained from this study provide key insights into the field pilot design of well spacing in shale gas reservoirs with complex natural fractures.

scholarly journals Simulation Study to Evaluate the Impact of Fracture Parameters on Shale Gas Productivity

2020 ◽  
Vol 39 (2) ◽  
pp. 432-442
Author(s):  
Abdul Majeed Shar ◽  
Waheed Ali Abro ◽  
Aftab Ahmed Mahesar ◽  
Kun Sang Lee
Keyword(s):  
Shale Gas ◽  
Gas Production ◽  
Simulation Software ◽  
Production Performance ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Shale Gas Reservoir ◽  
Fracture Parameters ◽  
Shale Gas Reservoirs ◽  
The Impact

The production from shale gas reservoirs has significantly increased due to technological advancements. The shale gas reservoirs are very heterogeneous and the heterogeneity has a significant effect on the quality and productivity of reservoirs. Hence, it is essential to study the behavior of such reservoirs for accurate modelling and performance prediction. To evaluate the impact of fracture parameters on shale gas reservoir productivity using CMG (Computer Modelling Group) stars simulation software was the main objective of this study. In this paper, a comprehensive analysis considering an example shale gas reservoir was conducted for production performance analysis considering uniform and non-uniform fractures configurations. Several simulations were performed by considering the multi-stage hydraulically fractured reservoir. The sensitivities conducted includes the different cases of moderate and severe heterogeneity along with variable fractures half-length, effect of changing fracture spacing, variable fracture conductivities. The simulation results showed that by increasing conductivity of fracture increases the gas production rate significantly. Moreover, cases of reservoir permeability heterogeneity were analyzed which show the significant effect on gas rate and on cumulative gas production. The results of this study can be used to improve the effectiveness in designing and developing of shale gas reservoirs and also to improve the accuracy of analyzing heterogeneous shale gas reservoir performance.

scholarly journals Analysis of the Influencing Factors on the Well Performance in Shale Gas Reservoir

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Cheng Dai ◽  
Liang Xue ◽  
Weihong Wang ◽  
Xiang Li
Keyword(s):  
Shale Gas ◽  
Gas Flow ◽  
Gas Production ◽  
Recovery Factor ◽  
Natural Fracture ◽  
Total Production ◽  
Gas Reservoir ◽  
Free Gas ◽  
Shale Gas Reservoir ◽  
Adsorbed Gas

Due to the ultralow permeability of shale gas reservoirs, stimulating the reservoir formation by using hydraulic fracturing technique and horizontal well is required to create the pathway of gas flow so that the shale gas can be recovered in an economically viable manner. The hydraulic fractured formations can be divided into two regions, stimulated reservoir volume (SRV) region and non-SRV region, and the produced shale gas may exist as free gas or adsorbed gas under the initial formation condition. Investigating the recovery factor of different types of shale gas in different region may assist us to make more reasonable development strategies. In this paper, we build a numerical simulation model, which has the ability to take the unique shale gas flow mechanisms into account, to quantitatively describe the gas production characteristics in each region based on the field data collected from a shale gas reservoir in Sichuan Basin in China. The contribution of the free gas and adsorbed gas to the total production is analyzed dynamically through the entire life of the shale gas production by adopting a component subdivision method. The effects of the key reservoir properties, such as shale matrix, secondary natural fracture network, and primary hydraulic fractures, on the recovery factor are also investigated.

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