Geo-Mechanical Property Analysis of Unconventional Reservoirs
1. Introduction
1.1 Shale Gas Fracking
Shale gas was the major source for the natural gas or hydrocarbons. It is obtained from the earth at below 3000 meters. Hydraulic fracturing was a method used to obtain this gas. This technique also known as fracking. Here the deep drill was made on the earth. Then the steel pipe covered with many layers was inserted in the bore hole. After that the small cracks are developed. Then the high pressure fluid (water) pumped inside the bore well. Then the cracks are propagated. After that the shale gas was collected continuously (“Fracking Shale Gas and the Gas Fracking Process”, 2018).
Shale gas is seen mostly on the shale. For the formation of shale gas two methods are used. One is horizontal drilling and other is hydraulic fracturing. In hydraulic drilling is used to get the gas in the inner where gas is formed deeply. A vertical well is bored to the rock which is the target (“Fracking pros and cons explained”, 2018). Then by the lake horizontally drill bit modified to drill a well that well is result in the formation of shale. Hydraulic fracturing is also called as a hydro fracking else fracking, it is a method for pumping the chemicals, water, sand to the well to free the hydrocarbons cached by the shale formed by the fractures(cracks) in the rock and from the shale natural gas is flowed to the well (“Shale Gas Fracking”, 2018). When in use of both hydraulic fracturing, horizontal drilling the extraction of shale gas is possible at the low cost. The natural gas does not flow frequently and trading quantity cannot be produced by the shale (“10 Chief Pros and Cons of Hydraulic Fracturing”, 2018).
Conventional gas reservoirs are produced when natural gas travel toward the Earth’s surface from an organic-rich source formation into highly permeable reservoir rock, where it is cached by an overlying layer of impermeable rock. In difference, shale gas resources are formed within the organic rich shale source rock (Bagudu, McDougall & Mackay, 2018). The low permeability of the shale largely suppress the gas from migrating to more permeable reservoir rocks (“Shale Gas 101 | Department of Energy”, 2018). Without horizontal drilling and hydraulic fracturing, shale gas production would not be economically possible because the natural gas would not flow from the production at large enough rates to justify the cost of drilling (Adelinet, Barnoud, Clochard & Ricarte, 2013).
1.2 Unconventional Reservoir
Unconventional reservoir the name tells that it was not similar to the conventional structure and practice. Oil and Gas requirements are increasing day to day. So that there are many methods are used to collect the oil from the earth’s crust. In conventional oil or gas reservoirs has many disadvantages (Al-Rbeawi, 2017). To overcome this problems a new technique that was invented. And it was called us unconventional reservoirs. In the existing system the soil deformation was the main problem. Because of that there are many problems occurs (“Forecasting physical and reservoir characteristics of reservoir formations for exploration of unconventional gas”, 2014). But in unconventional technique the non-deformable resource was developed by extract the gases and oils by creating the small cracks instead of creating the huge hole in the earth. In the below figure the difference between the conventional as well as unconventional reservoir was shown (2018)..
Figure 1 Difference between Conventional and Un-conventional Reservoirs
1.3 CMG Software
CMG stand for the Computer Modelling Group Ltd. There are many simulation software tools are developed and sold by this company. CMG is one of the biggest ‘pure play’ reservoir simulation company around the world. CMG has essential contribution that has been its effect and great support for the scientific community, like universities, that has made the course for innovative research, leading to building the reservoir simulation in future CMG is helpful in designing the oil and gas reservoirs inner underground to find out the possible way of developing it (Becker, Zhang & Ayala H, 2016)
. This type of software is greatly difficult and technical and need domain specialist in physics, computer science, mathematics and reservoir engineering which gives an entry. This software is a huge mission critical to gas and oil producers (Moghadam & Chalaturnyk, 2017). Though it is a high priced rate software it is less compared to suboptimal work developing the reservoir. Among them the reservoir analyzing software tool was highly renovated product of the company (Shad, Holmgrün & Calogirou, 2016). They provides three reservoir analyzing software tools. And they are listed below.
- IMEX
- GEM
- STARS
Here each module has its own specifications. Each modules are used for certain applications. IMEX was used for the conventional black oil recovery analysis process. It is highly used for oil recovery process. GEM was used for the unconventional reservoir analysis. In our case the unconventional reservoir need to be analyzed (Mohamadi, Wan & Shen, 2017). For that the GEM module was selected. And the STARS was the advanced module, has the thermal analyzing facility of the reservoirs. In addition it gives CMOST, it is a reservoir engineering device that contain sensitivity analysis, optimization of reservoirs and history matching (Stalgorova & Mattar, 2013).
1.4 Problem Statement
In this project the numerical analysis of the unconventional reservoir was need to be analyzed. For that the set of data required for the analysis was provided. The CMG analysis was need to be done by the given set of details (Paryani, Awoleke, Ahmadi, Hanks & Barry, 2017). For that the GEM module was needs to be used. Then the various results and graphs are need to be plotted by using the same software itself (CMG).
2. Key Objectives
The main objective of the project was to analyze the various geo-mechanical properties of the unconventional shale gas reservoirs to the development of the effective shale gas fracking design to assist the filed planning and implementation. For that, the following things are needed to be done in this project. The below-listed things are the key objectives of the project. And they are listed below (Denney, 2013).
- To carry out the detailed study of the shale gas fracking process and numerical analysis software (CMG).
- To identify the problem and collect the data required for the analysis.
- To develop the model in the CMG software.
- To assign Properties in the developed model (Denney, 2012)
- To carry out the analysis and simulation in the same software itself.
- Generate the various results and graphs for the developed model (“Pros and Cons of Fracking – Conserve Energy Future”, 2018).
3. Need of Geo-Mechanical Property Analysis
The overall effectiveness of the hydrocracking or shale gas extraction process was depends on the geo-mechanical properties of the system. Because the geo-mechanical properties plays the major role in the shale gas extraction from the earth. In the unconventional technique the well has only cracks with the small thickness (Carpenter, 2014). So the collection of the gas by the well depends on the rock permeability and some other parameters. Hydrocarbon extraction wells are highly dangerous, because they are highly flammable (Steel, Mackay & Maroto-Valer, 2018). So the very small mistake leads to a very big losses like financial losses, human losses etc. So they are need to be designed very carefully. For that the geo-mechanical property analysis was too important (Carpenter, 2018). Based on these details only the well-design was developed. For the efficient well or unconventional reservoir the geo-mechanical property must analyzed before the development. This analysis acts as a guidelines for the design of the well or unconventional reservoir (“Rock mechanical properties -“, 2018). Based on this parameter only the drilling methodology was selected. The drill size as well as the crack size depends on the stability of the rock system. Also the moisture content in the rock also impacts on the shale gas extraction process. Here the major geo-mechanical properties and their importance was discussed (Santiago & Kantzas, 2017). And they are,
- BD – Bulk Density
- Sonic Porosity
- BM – Bulk Modulus
- SM – Shear Modulus
- YM – Young’s Modulus
- PR – Poisson’s Ratio
- TMHS – Total Minimum Horizontal Stress
The detailed overview of the above stated geo-mechanic properties are given in the below context also the impact of those properties in the shale gas extraction well was discussed here (Chen, Liao, Zhao & Li, 2018).
3.1 Bulk density
The bulk density is described as total mass divided by the total volume. It is also known as the soil density. Normally the bulk is the collection of object mass and the density is the quantity of matter in the soil. The bulk density make the impact in the hydrofracking. And these densities are used to mention the range of soil condition (Uzun, Kurtoglu & Kazemi, 2016). The volume of content is important in the soil factors. And the type of soil affect the factors through the volumes.
3.2 Sonic porosity
The sonic porosity is derived by using the matrix interval transmit time. The changes of sonic porosity are described by the tolerance limit. The porosities of the object with fractures are calculated by the formula and the values for the porosity comes very low. And the calculation part includes acoustic transit time (Miskimins, 2009).
3.3 Bulk modulus
Normally the bulk modulus is described as the ratio of ininitesimal pressure. And it used to improve the output of the volume.
The above-mentioned formula is used in the bulk modulus. And here in the formula p and v are known as the pressure and volume. The pressure derivation should with the respect to the volume. And using this formula we can make the density of the object. It is used to describe the variation in the temperature during compression. The modulus is used to describe the response of the materials to the hydrostatic pressure.
3.4 Shear modulus
It is described as the ratio of shear stress to the shear strain.
Here in the formula G is defined as the shear modulus. And the unit of this modulus is Pascal. This modulus describes the response of the materials to the stress. The metals in the modulus are used to get the analysis of temperature in the way of increasing or decreasing (Liang, Khan & Puspita, 2018)
3.5 Young’s modulus
It is the geo-mechanical property of the solid materials. And this modulus is described as the relation between the material stress and strain. In the modulus, the material properties are analyzed by using the strength, hardness, and toughness. The Young’s modulus is not similar to all materials. But the properties are the same for all material.
The above mentioned formula is used in the young’s modulus. Here the E is described as the calculation of dividing the stress. F is the force and L is the length of the object.
3.6 Poisson’s ratio
It is described as the negative of the ratio of transverse strain to axial strain. And the ratio is the poison effect measurement.
3.7 Total minimum horizontal stress
The minimum horizontal stress is used in the hydro-fracking and sand production. And the stress is analyzed by using the direct methods. They are leak off and mini-frac tests. The equation contains some parameters (Ganguly & Cipolla, 2012) (Wanderley de Holanda, Gildin & Valko, 2018). They are elastic, shear sonic logs and core data. The geo-mechanics property is constructed to get the minimum stress in the way of horizontal. And several algorithms are used to get the minimum horizontal stress.
4. CMG Analysis Procedure
CMG- Analysis was a one kind of the numerical analysis. Here we need to develop the mathematical mode of the problem first. Then we need to develop the governing conditions (Boundary conditions) for the system. Then the variables are assigned for the developed model. After that the model was simulated by using the best suited modules. In this project the design or mathematical model was developed by using the CMG builder module. Then the variables are assigned in the form of ‘.csv file format’ as well as ‘.xlsx file format’ and also the ‘.xml file format’ (Kydland, Haugan, Bousquet & Havig, 1988). In this section the detailed explanation about the processes involved in the CMG analysis process was given. The CMG analysis for the unconventional reservoir or shale gas well was done by the following four steps (Li, Xing, Liu & Liu, 2015). And they are given below.
- Data preparation.
- Mathematical Model Development.
- Result Generation.
4.1 Data Preparation
Data preparation was the major process involved in the CMG analysis process. The overall effectiveness of the method depends on the quality of the data preparation. In this step the various set of information about the process was collected by using the different set of procedures. In this section the data preparation techniques was explained with full details. These details are collected by the processes like monitoring the well or unconventional reservoir, calculation of properties by using the standard formulas etc. Data preparation is the first step used for developing the data-driven models. The accuracy of data is calculated by the data preparation method. And also it allows only the correct file format in a computer file. By developing a data structure and documenting the data structure is done by next steps. Different types of properties are used. This study, we need to take a dataset from the available logs. These datasets are used for rock verses depth method. And also it portraits some specific properties. First, we need to identify the production pay zone. The production pay zone is available in conventional good logs along with the horizontal logs. Once the depth is identified then go to the next step. In this contains a lot of Marcellus scales from conventional good logs. Such as gamma rays and information. Each and every individual will have separate information, these pieces of information are extracted by good logs. We are using some log characteristics and tools. Using this model you can easily find out the differences between two or more production pay zones. These production pay zones are also using the same datasets. We need to specify the contrast between pay zones and the adjacent rocks. Such as upper Marcellus, Purcell, lower Marcellus, and Onondaga. The data set contains two things one is row and another one is a column (Wihbey & Wihbey, 2018) (Zhang, Becker & Ayala, 2016). The rows and columns contain lots of data such as the good name, the good coordinates, and the value of gamma-ray, bulk density, sonic porosity, bulk modulus, shear modulus, young modulus, poisons ratio, and total minimum no of horizontal stress. All the data’s are not included in geo-mechanical good logs. And also it calculates the geo-mechanical values. The following image shows the data prepared for the analysis from the various resources.
Figure 2 Microcosmic Data Collected for the Unconventional Reservoir Model Analysis.
4.2 Mathematical Model Development
Mathematical model development was the second step of the CMG analysis process. Here the mathematical model was developed for the unconventional reservoir or shale gas extraction well. It was created by using the CMG – Builder software. For that, the values or data collected in the previous step was used. Mathematical modeling for the shale gas well is a notable and very important method in the fluid mechanics and this method is successfully implemented in the technology of construction and building for developing the gas and oil reservoir. Shale is a fine-grained and sedimentary rock which is clastic in nature. The capacity and structure of the shale are very tiny that is used to make spaces. Also they are minute for the oil, water, and gas for traveling through the shale. So it is served by compelling common gases and rocks. Shale gas stores, which are likewise called source rock reservoirs (SRR), have kind properties that make water driven cracking a basic alternative keeping in mind the end goal to start a financial level of the petroleum gas generation. The spaces of interstitial in the shale are very tiny and minute to calculate that. Which can take up to a high volume of the rock and that gives the shale for the worthy calculations of oil, water and gas and they not have the capability for emitting them that results from less permeability and the business of another fluid that is petroleum have won the confinements of shale makings in the following reasons like permeability, porosity, cracking of hydraulics and penetrating levels. So the calculation of interstitial spaces for the shale is very difficult for each and everything. Numerous examines are led from shale pore-scale level to field scale repository reenactments to enhance the comprehension of complex stream conduct that is produced and talked about through numerical, logical, and semi-analytical supply models for whimsical supplies. Dissimilar to customary gas stores, inadequate penetrability, the ultra-low porosity of shale shake, and constrained store contact territory be that as it may, inconceivably natural rich development, can’t offer generation in a business esteem without incitement forms. The developed mathematical model by using the CMG Builder seems like the image below given.
Figure 3 Mathematical Model Developed by CMG-Builder
4.3 Simulation
To set boundary condition when modeling the reservoir
Consistent weight limit at the one side of the supply is satisfactory is there is just creation and no pressurization over the first limit weight is occurring and the repository extension at the open side has an interminable conduct. Moreover, is it perhaps conceivable to demonstrate the one side store extension with a predetermined number of extensive lattice cells to impersonate the volumetric conduct of the extension in mix with balanced limit transfer. If there should be an occurrence of over-compelling the consistent weight limit condition will confine genuine forcing up of the liquid infused some portion of the store. The other main things for governing the values in the boundary conditions are: pressure and permeability.
GEM (Geo-Mechanics Simulation Software)
GEM is the software for reservoir simulation and it is also the leading software programming for chemical and unconventional reservoir and also the compositional software. The scope of work processes gave by our geo mechanics programming and administrations gives penetrating, store, and creation engineers with the devices and know-how to completely coordinate geo mechanics into the basic leadership forms. The mechanical reaction of the subsurface amid consumption, infusion, and temperature changes can influence numerous parts of penetrating, generation, and supply conduct. Which is used in the following methodologies:
- Shale gas and liquids, Coal bed methane and oil/gas which is tight in nature.
- Enhanced Oil Recovery (Hydrocarbon and Acid Gas Injection)
- Gas, Gas Condensate and Volatile Oil
- Carbon Capture and Storage (CSS)
- Unconventional Oil, Gas and Liquids Rich Reservoirs (Shale Gas/Liquids, Tight Oil/Gas, and Coalbed methane.
- Naturally or Hydraulically Fractured Reservoirs
- Foam and Geochemical EOR (Enhanced Oil Recovery)
GEM for unconventional reservoir
To open shale gas it is critical to amplify the well contact region to guarantee the most astounding generation rates. This is frequently accomplished by water powered breaking, contact-stunned cracking innovation, and level penetrating. Arranging effective culminations and creation requires a grid information of the shale’s heterogeneity and anisotropy. The operators in the unconventional reservoir are developed the most costliest and complex gas and oil plays and that shows the idea and understandings of the geo mechanical behaviors. In outlining the improvement design it is additionally imperative to consider the area and conduct of characteristic cracks, and in addition anisotropy and heterogeneity in the shale gas well. These components impact the accomplishment of pressure driven breaking and coming about creation. Thorough 3D demonstrating is given by the Petrel Geo mechanics framework and pressure driven crack displaying by utilizing a well-driven model.
Figure 4 Simulation of the Developed Model Using the CMG-GEM Module.
4.4 Results Generation
Results generation was the final step of the CMG analysis process. For that the same software was used. In this stage the results for the developed mathematical model of the unconventional reservoir was generated. These results may be in the form of graphs or images or animations. This results support us to take the decisions on the shale gas extraction process. In our case there are four cases are analyzed. The first case was the basic model. Here the shale gas well was developed without considering the effects of the geo-mechanical property. It was saved in the name of ‘Shale Gas Model’. In this model the seismic behavior of the soil only considered. After that the model was improved by adding the hydraulic fractures. It was saved in the name of ‘Shale Gas Model_HF’. Here the hydraulic fracking parameters are added in the design. Then the same model was improved by adding the extra details like nodes and pressure etc. on the developed model. It was saved in the name of ‘Shale Gas Model_ND’. After that the all the parameters involved in the hydraulic fracking was assigned to the model. And it was the final model for the project. Here the Developed models as well as the simulated results was attached. To open this results and developed model we need the CMG software.
5. Key Findings
Based on the analysis carried out in the Unconventional reservoir system, (Shale gas extraction well) the following results are founded. And they are described here. In this analysis the seismic data for the soil and rock system present in the unconventional reservoir was given. The starting date for the analysis was considered as 2000-Jan-1. From this date the geo-mechanical behavior of the system was analyzed.
5.1 Shale gas Match History
Shale gas match history was the major result obtained from the CMG analysis of the unconventional reservoir (Shale gas well). Here the comparison of the simulation results as well as the production results are given. Here the two main parameters are considered. One is Gas rate extracted from the well and another one is the water rate used in the well. Here the comparison graphs are added. The detailed explanation for the generated graphs are given below.
Gas Rate vs. Time.
In the below graph was plotted among the gas rate vs. time. Here the there are two cases are compared. One is the production rate of the well. This value was the actual value. The second one was simulated results. This values are predicted values. This values are software generated values based on the model and simulation done on the software. From the graph the decreasing nature of the gas rate was noticed. It reduced with respect to time. The gas rate was the simulation result was slightly higher than the actual production rate.
Water Rate vs. Time
The graph given below was plotted among the values between the water rate as well as Time. Similar to the gas rate diagram here the relation between the water rate as well as time was shown. The water rate decreases with the increase of the time. Also the relation between the simulation results as well as the actual values are described in the graph given below.
6. Conclusion
In this project, the CMG analysis of the shale gas fracking procedure was successfully completed. The important analysis of geo-mechanical property is studied in this project. The analysis of many geo-mechanical properties of the unconventional shale gas reservoir to the formation of the shale gas fracking model is done successfully. For hydrocarbons and natural gas shale gas is the main source. Hydraulic fracturing and horizontal drilling are the main technique used in this. It is seen among the shale place. The detailed study of this shale gas is given. A model is created in the CMG software and the properties are given in the developed model. The simulation and analysis in the CMG software are done successfully. CMG is a computer modeling group software. It has a great impact on reservoir simulation. That software detail description is given in this project. The project on Numerical CMG analysis and shale gas fracking process is studied clearly in this project.
7. References
10 Chief Pros and Cons of Hydraulic Fracturing. (2018). Retrieved from https://greengarageblog.org/10-chief-pros-and-cons-of-hydraulic-fracturing
(2018). Retrieved from https://www.cmgl.ca/uploads/files/pdf/TRAINING/CMG_2013_training_catalogue.pdf
Adelinet, M., Barnoud, A., Clochard, V., & Ricarte, P. (2013). Improved unconventional reservoir characterization using multi-azimuth stratigraphic inversion, case study on the Fort Worth Basin. Journal Of Unconventional Oil And Gas Resources, 3-4, 15-26. doi: 10.1016/j.juogr.2013.10.001
Al-Rbeawi, S. (2017). How much stimulated reservoir volume and induced matrix permeability could enhance unconventional reservoir performance. Journal Of Natural Gas Science And Engineering, 46, 764-781. doi: 10.1016/j.jngse.2017.08.017
Bagudu, U., McDougall, S., & Mackay, E. (2018). Network modelling analysis of a depressurization experiment on a North Sea reservoir core sample. Journal Of Petroleum Science And Engineering, 162, 63-75. doi: 10.1016/j.petrol.2017.11.036
Becker, M., Zhang, M., & Ayala H, L. (2016). On the pressure-saturation path in infinite-acting unconventional liquid-rich gas reservoirs. Journal Of Natural Gas Science And Engineering, 35, 97-113. doi: 10.1016/j.jngse.2016.08.007
Carpenter, C. (2014). Unconventional-Reservoir Development in Mexico. Journal Of Petroleum Technology, 66(07), 122-126. doi: 10.2118/0714-0122-jpt
Carpenter, C. (2018). Unconventional-Reservoir Characterization With Azimuthal Seismic Diffraction Imaging. Journal Of Petroleum Technology, 70(03), 92-94. doi: 10.2118/0318-0092-jpt
Chen, Z., Liao, X., Zhao, X., & Li, X. (2018). Appraising Carbon Geological-Storage Potential in Unconventional Reservoirs: Engineering-Parameters Analysis. SPE Reservoir Evaluation & Engineering, 21(02), 476-488. doi: 10.2118/189442-pa
Denney, D. (2012). Improve Unconventional-Reservoir Completion and Stimulation Effectiveness. Journal Of Petroleum Technology, 64(10), 115-119. doi: 10.2118/1012-0115-jpt
Denney, D. (2013). Integrated Dynamic-Flow Analysis To Characterize an Unconventional Reservoir. Journal Of Petroleum Technology, 65(02), 127-131. doi: 10.2118/0213-0127-jpt
Forecasting physical and reservoir characteristics of reservoir formations for exploration of unconventional gas. (2014). “Proceedings” Of “Oilgasscientificresearchprojects” Institute, SOCAR, (1). doi: 10.5510/ogp20140100182
Fracking pros and cons explained. (2018). Retrieved from https://www.bbc.com/news/av/uk-england-lancashire-33230412/fracking-the-pros-and-cons-of-extracting-shale-gas
Fracking Shale Gas and the Gas Fracking Process. (2018). Retrieved from http://www.alternative-energy-tutorials.com/energy-articles/fracking-shale-gas.html
Ganguly, U., & Cipolla, C. (2012). Multidomain Data and Modeling Unlock Unconventional Reservoir Challenges. Journal Of Petroleum Technology, 64(08), 32-37. doi: 10.2118/0812-0032-jpt
Kydland, T., Haugan, P., Bousquet, G., & Havig, S. (1988). Application of Unconventional Techniques in Constructing an Integrated Reservoir Simulation Model for Troll Field. SPE Reservoir Engineering, 3(03), 967-976. doi: 10.2118/15623-pa
Li, Q., Xing, H., Liu, J., & Liu, X. (2015). A review on hydraulic fracturing of unconventional reservoir. Petroleum, 1(1), 8-15. doi: 10.1016/j.petlm.2015.03.008
Liang, B., Khan, S., & Puspita, S. (2018). An Integrated Modeling Work Flow With Hydraulic Fracturing, Reservoir Simulation, and Uncertainty Analysis for Unconventional-Reservoir Development. SPE Reservoir Evaluation & Engineering, 21(02), 462-475. doi: 10.2118/187963-pa
Miskimins, J. (2009). Design and Life-Cycle Considerations for Unconventional Reservoir Wells. SPE Production & Operations, 24(02), 353-359. doi: 10.2118/114170-pa
Moghadam, A., & Chalaturnyk, R. (2017). Rate dependency of permeability in tight rocks. Journal Of Natural Gas Science And Engineering, 40, 208-225. doi: 10.1016/j.jngse.2017.02.021
Mohamadi, M., Wan, R., & Shen, Z. (2017). An elastoplastic description of frictional destructuration in natural clays and shales. Acta Geotechnica. doi: 10.1007/s11440-017-0585-6
Paryani, M., Awoleke, O., Ahmadi, M., Hanks, C., & Barry, R. (2017). Approximate Bayesian Computation for Probabilistic Decline-Curve Analysis in Unconventional Reservoirs. SPE Reservoir Evaluation & Engineering, 20(02), 478-485. doi: 10.2118/183650-pa
Pros and Cons of Fracking – Conserve Energy Future. (2018). Retrieved from https://www.conserve-energy-future.com/pros-and-cons-of-fracking.php
Rock mechanical properties -. (2018). Retrieved from http://petrowiki.org/Rock_mechanical_properties
Santiago, C., & Kantzas, A. (2017). Chromatographic separation and liquid drop-out in unconventional gas reservoirs. Journal Of Petroleum Science And Engineering, 159, 553-563. doi: 10.1016/j.petrol.2017.09.049
Shad, S., Holmgrün, C., & Calogirou, A. (2016). Near wellbore thermal effects in a tight gas reservoir: Impact of different reservoir and fluid parameters. Journal Of Unconventional Oil And Gas Resources, 16, 1-13. doi: 10.1016/j.juogr.2016.09.002
Shale Gas 101 | Department of Energy. (2018). Retrieved from https://www.energy.gov/fe/shale-gas-101
Shale Gas Fracking. (2018). Retrieved from https://www.waterworld.com/articles/wwi/print/volume-27/issue-2/regional-spotlight-europe/shale-gas-fracking.html
Stalgorova, K., & Mattar, L. (2013). Analytical Model for Unconventional Multifractured Composite Systems. SPE Reservoir Evaluation & Engineering, 16(03), 246-256. doi: 10.2118/162516-pa
Steel, L., Mackay, E., & Maroto-Valer, M. (2018). Experimental investigation of CO 2 -brine-calcite interactions under reservoir conditions. Fuel Processing Technology, 169, 122-131. doi: 10.1016/j.fuproc.2017.09.028
Uzun, I., Kurtoglu, B., & Kazemi, H. (2016). Multiphase Rate-Transient Analysis in Unconventional Reservoirs: Theory and Application. SPE Reservoir Evaluation & Engineering, 19(04), 553-566. doi: 10.2118/171657-pa
Wanderley de Holanda, R., Gildin, E., & Valko, P. (2018). Combining Physics, Statistics, and Heuristics in the Decline-Curve Analysis of Large Data Sets In Unconventional Reservoirs. SPE Reservoir Evaluation & Engineering. doi: 10.2118/185589-pa
Wihbey, J., & Wihbey, J. (2018). Pros and cons of fracking: 5 key issues » Yale Climate Connections. Retrieved from https://www.yaleclimateconnections.org/2015/05/pros-and-cons-of-fracking-5-key-issues/
Zhang, M., Becker, M., & Ayala, L. (2016). A similarity method approach for early-transient multiphase flow analysis of liquid-rich unconventional gas reservoirs. Journal Of Natural Gas Science And Engineering, 28, 572-586. doi: 10.1016/j.jngse.2015.11.044
