Browsing by Author "Ehlig-Economides, Christine"
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Item Accelerating Computations for Oil and Gas Problems: Reduced Physical Modeling of Hydraulic Fracturing and High-Performance Computing for Fluid Flow in a Porous Medium(2020-08) Protasov, Innokentiy; Ballarini, Roberto; Dontsov, Egor; Sharma, Pradeep; Ehlig-Economides, Christine; Krakowiak, Konrad J.; Momen, MostafaThe mechanical modeling of hydraulic fractures is a mathematically complex problem involving the coupling between the equations that describe fracturing of and fluid flow through the porous rock, and fluid flow inside the fractures. Simulation of these physical processes can offer critical insights into practical design problems associated with hydraulic fracturing technology. However, exploration of the influence of the relatively large number of control variables defining the design space is limited by the available computational resources. Generally speaking, the computational time can become a bottleneck for practical usage of available hydraulic fracture simulators. Acknowledging this limitation, this thesis presents a series of combined analytical-computational models that enable efficient simulation of the propagation of multiple non-planar hydraulic fractures, within the context of hardware-conscious advanced numerical techniques. Hydraulic fracture simulations are often coupled with the fluid flow within the surrounding porous rock. This thesis realizes the need for computationally efficient porous media flow simulations that achieve a similar level of efficiency as the fast hydraulic fracturing models. Remarkable computational efficiency is achieved through the novel formulations of numerical techniques and the state-of-the-art computational methods: reduced-order modeling of the hydraulic fracturing, and the application of physical block solvers to the porous media flow.Item Alternatives to Decline-Curve Models for Unconventional Reservoirs: A Case for Data-Driven Discovery of Natural Laws(2017-12) Thakur, Bharat; Nikolaou, Michael; Ehlig-Economides, Christine; Thakur, Ganesh C.Decline curve models, such as the Arps decline model and its variants, are fairly inaccurate for unconventional reservoirs. Therefore, usually hybrid models, combining early transient-flow models such as Duong and SEPD with Arps for boundary-dominated flow, are usually employed. However, in unconventional reservoirs with multiphase flow these transitions are gradual. Further, for transition period between transient flow and boundary dominated flow, there is no consensus for what is the appropriate model structure. In this study large database of available field data referring to production from unconventional reservoirs is analyzed using multivariate statistical method, such as principal component analysis (PCA). The analysis suggests that over 90% of variability in the data can be captured with only one or two latent variables. Therefore, an appropriate model structure naturally emerges from the data, thus eliminating the need to separate production into different flow-related regimes with explicit formulas for corresponding decline curves.Item Anisotropic Fracture Toughness Characterization of Shale Formation from Drill Cuttings(2022-05-10) Esatyana, Erica; Sakhaee-Pour, Ahmad; Farouq Ali, S. M.; Ehlig-Economides, Christine; Wong, George K.; Sepehrnoori, KamyShale is a sedimentary rock composed of clay minerals and silt-sized particles. Its pore throat sizes are as small as 10 nm in its matrix, which leads to ultralow permeability. It has become economically viable for hydrocarbon recovery because of hydraulic fracturing, in which the required energy is defined by fracture toughness. Shale is mechanically unstable and retrieving a suitable core size for common tests is costly and time-consuming. Thus, there is a need to develop new methods applicable to small pieces such as drill cuttings, which are often the only sources available in real-time conditions. This study proposes two methods for the geomechanical characterization of shale at the core scale based on the interpretation of small-scale measurements. Both rely on nanoindentations. The proposed conceptual models have applications in characterizing formation heterogeneity in the petroleum industry. The first determines Young’s moduli from cuttings, and the results are compared with those of the core plugs from the Wolfcamp Formation. The sensitivity of the results to sample preparation is also discussed. The second method characterizes the fracture toughness of shale based on the conceptual model proposed in accordance with the effective medium theory. The proposed model sheds light on the complexities of the induced fracture patterns in shale that differ from those observed in homogeneous materials, such as fused silica and aluminum. The conceptual model is realistic for shale because it captures the sample heterogeneity. The second method is tested at a small scale using different tip geometries. The interpreted fracture toughness values from the cube-corner and Berkovich tips are close, with less than 18% difference, which provides a partial validation for the conceptual model. The proposed model is also tested against independent data obtained from the cracked Chevron notched Brazilian disc (CCNBD) test. The difference between predicted fracture toughness values from nanoindentation and the CCNBD test is less than 13%, and this good agreement validates the proposed model. The proposed model has applications in characterizing the mechanical properties of shale using small samples from unconventional resources.Item Applying Predictive Analytics to detect and diagnose impending problems in Electric Submersible Pumps(2015-08) Gupta, Supriya; Nikolaou, Michael; Ehlig-Economides, Christine; Grigoriadis, Karolos M.The electrical submersible pump (ESP) is currently the fastest growing artificial-lift pumping technology. Deployed across 15 to 20 percent of oil-wells worldwide, ESPs are an efficient and reliable option at high production volumes and greater depths. However, ESP performance is often observed to decline gradually and reach the point of service interruption due to factors like high gas volumes, high temperature, and corrosion. The financial impact of ESP failure is substantial, from both lost production and replacement costs. Therefore, ESP performance in extensively monitored, and numerous workflows exist to suggest actions in case of breakdowns. However, such workflows are reactive in nature, i.e., action is taken after tripping or failure. Furthermore, given the emerging trend in the E&P industry of using downhole sensors for real-time surveillance of parameters impacting ESP performance there is an opportunity for predicting and preventing ESP shutdowns using data analytics. Therefore, a data-driven analytical framework is proposed to advance towards a proactive approach to ESP health monitoring based on predictive analytics to detect impending problems, diagnose their cause, and prescribe preventive action.Item Determining Fluidization Across Gravel Pack Completion to Confirm its Integrity(2017) Bhowmick, Ankit; Ehlig-Economides, ChristineThe aim of this research is to understand the relationships determining pressure drop across an undamaged gravel pack such that the velocity for non-uniform inflow from the reservoir can be determined at the screen and at the sandface. Further, this study aims at determining the minimum inflow velocity sufficient to destabilize the gravel pack bed and thus, impair it, hence determine the minimum fluidization velocity. A CFD model for such a case hasn?t been done before in the oil and gas industry. We have created a model that describes the internal gravelpack dynamics of fluid and proppantItem Determining Gravelpack Fluidization Flow Velocity(2017-12) Bhowmick, Ankit; Ehlig-Economides, Christine; Wong, George K.; Kirkpatrick, RodIn a gravelpack completion, non-uniform reservoir inflow with very high velocity can fluidize the gravel and/or erode the sand screen. Previous works have addressed the risks of fluidizing the gravelpack in high flow rate deepwater wells and have quantified a critical velocity above which fluidization is at risk. However, no formal mathematical model has justified the value, and details of the failure mechanism are lacking. The gravelpack screen is equipped with a basepipe with a pattern of holes through which fluid must pass after flowing through the gravelpack and screen. In a cased hole completion fluid reaches the pack through a pattern of perforation tunnels opening into the pack. The result is a complex flow pattern inside the pack involving both vertical and annular flow in addition to the expected radial flow. Alternatively, during high rate flow, alignment of a single perforation with a hole in the basepipe could produce a jet effect. The aim of this thesis is to create a simulator that models gravelpack dynamics including fluidization and to determine the minimum fluidization velocity in a gravelpack completion with given casing, screen, and basepipe geometries. The ANSYS-FLUENT simulator enables modeling of flow through the gravelpack governed by the particle motion phenomena according to the Euler-Euler approach that treats each of two phases (inflowing hydrocarbon and the gravel) as a continuum. Results of this study will be useful in designing gravelpack completions in ultra-high rate wells.Item Evaluation of Pump and Treat Technology for Removal of Methane Contamination in a Fresh Water Aquifer(2017-05) Thomas, Gevargis; Ehlig-Economides, Christine; Hatzignatiou, Dimitrios G.; Kostarelos, KonstantinosAn operating company has used salt caverns for storage of natural gas since their creation in 1971. A casing leak developed in a gas storage well used for gas injection into and production from a salt cavern. Evidence suggests that natural gas that escaped because of the casing leak flowed into regional fresh water aquifers located in formation layers above the storage cavern. Measurements in wells penetrating the aquifers show that the groundwater flows in each in a regional NW to SE direction. Removal of organic and inorganic contaminants from groundwater is done using a pump and treat system. The objective for the proposed study is to evaluate the effectiveness of pump and treat ground water remediation technology to prevent further migration of gas downstream and remove the methane contamination from the aquifer.Item EXPERIMENTAL AND NUMERICAL STUDY OF THE PRESSURE SURGE EFFECT AND MAGMA CHAMBER RESONANCE(2023-08) Jin, Yuesu; Zheng, Yingcai; Suppe, John; Ehlig-Economides, Christine; Zhou, Hua-WeiThis dissertation is devoted to study elastodyanmic responses of a fluid-filled crack and a magma chamber in the subsurface using laboratory experiment and numerical modeling. I have made two important findings: i) a fluid-filled fracture can dynamically amplify the fluid pressure inside the fracture; ii) the presence of free surface is critical in generating long-period long-duration (LPLD) signals in volcano seismology. To be specific, the first finding is on laboratory verification of the Pressure Surge effect, where the fluid pressure in a fracture can be dynamically amplified relative to the incident wave pressure. I designed and built a low-frequency underwater system including a low-frequency acoustic source (Xfrac-S) using electromagnets that can generate low-frequency acoustic waves in the frequency range of 12~70Hz. I also built flexural transducers (Xfrac-H) that can measure the fluid pressure in the fracture directly. After investigating the effects of different frequencies and fracture apertures (0.2mm to 9.2mm), I achieved a maximum amplification factor about 25.2 using a 1.2-meter block. The Pressure Surge effect may be the underlying mechanism for multiple natural phenomena such as dynamic earthquake trigging, hydrogeological permeability change, and triggered mud volcano eruptions. The second finding is on the magma chamber resonance using a half-space boundary element modeling. I created a new 3D boundary element code to model the elastodynamic response of a magma chamber below the earth surface. I found the presence of the free surface can enhance the resonance energy of the magma chamber and generate LPLD signal much more efficiently. This modeling work provides a basis to constrain the magma chamber geometry and its depth using sparsely observed seismic data. In developing the BEM codes, I introduced a novel regularization of half-space Green’s functions in BEM which can reduce the integration time significantly. I also found a new expression for hypersingular Green’s functions which are critical in solving wave scattering by empty cavities in elastic media.Item Increasing Recovery Potential in a Tight Oil Reservoir(2017-12) Khandelwal, Ravi; Ehlig-Economides, Christine; Thakur, Ganesh C.; Qin, GuanLow estimates for primary oil recovery from tight oil reservoirs ranging from 5 to 10 percent prompt growing interest in enhanced oil recovery. The key to the success of any displacement process is assuring no connection exists between hydraulic fractures in injection and production wells. Well patterns likely to succeed feature positioning injector hydraulic fractures between the hydraulic fractures of producer hydraulic fractures. This study compares economics and recovery factors for primary, huff-n-puff, and displacement strategies for a multi-well pattern capable of providing many simultaneous planar displacements. This study addresses enhanced oil recovery for tight oil reservoir with and without secondary fractures. We use carbon dioxide as the injection fluid. We use the GEM compositional simulator developed by Computer Modelling Group to model primary production, huff-n-puff, and displacement for two planar fractures using formation and fluid properties typical for Eagle Ford play. Simulations apply a dual porosity model to consider varying secondary fracture extents from 10% to 50% of the distance between injection and production fractures. Multiplying by the number of plane-to-plane displacements in the multi-well pattern scales up to the field application. The presence of secondary fractures greatly affects the enhanced oil recovery efficiency. Oil recovery by gas flooding is less in the case where the secondary fractures are distributed throughout the field as compared to those in which natural fractures are activated near the wellbore. In contrast, the presence of secondary fractures greatly enhances oil recovery by huff-n-puff. The economic analysis indicates that the presence of secondary fractures affects the performance of gas flooding but still it performs better than huff-n-puff when the secondary fracture distribution remains below 50%. As the percentage of secondary fracture in the field increases, the nature of the net present value curve reverses indicating that the performance of huff-n-puff is superior to that of the gas flooding.Item Integrated Fluid and Heat Flow Model: Analyses and Operation of Subsea CO2 Injection System(2023-08) Effiong, Michael; Wong, George K.; Ehlig-Economides, Christine; Lee, Kyung Jae; Myers, Michael T.; Soliman, Mohamed Y.The required CO2 injection rate for carbon capture and storage (CCS) to meet the net zero ambition is significant. Deepwater (subsea) environments provide the potential for high rate, sustained injectivity and low well count. The subsea system is characterized by huge volumes of flowline and riser, relative to the well. Deepwater subsea environments are also characterized with high pressure and low temperature. In this research, we developed and validated a one-dimensional (1D) finite element model to analyze the non-isothermal fluid flow behavior of the integrated deepwater system that is comprised of surface, subsea and subsurface components. For improved efficiency, optimal storage density and operational stability, the desire is to inject CO2 at supercritical state, maintain dense phase in the entire system, avoid flash vaporization at any point along the system and during injection operations. The developed model demonstrates the feasibility of integrated subsea systems to meet these desired criteria. We conclude that for subsea systems, dense phase is maintained throughout the entire system over the range of depleted to geopressured reservoirs, high to low injectivity, various subsea geometry (riser, flowline length, pipe diameter) and during ramp-up operations. In the subsea system, the potential for flash vaporization is highest at the subsea wellhead under high injection rates. Frictional pressure drop is a crucial (non-linear) factor that exacerbates the liquid-vapor phase transition in deepwater (subsea) systems. This is contrary to onshore or shallow water development where flash vaporization is dominant for depleted reservoirs. The scenarios, cases and analyzed results from simulations conclusively support the objectives of this research. Deepwater (subsea) CCS is feasible and has technical and environmental benefits, relative to onshore and offshore environments. Prudent and proactive research to enable CCS in deepwater (subsea) must be advocated.Item Microseismic Motivated Model for Asymmetric Hydraulic Fractures in Adjacent Multiple Transverse Fracture Horizontal Wells(2018-12) Hu, Xiaofan; Ehlig-Economides, Christine; Dontsov, Egor; Qin, GuanEngineers commonly expect symmetric fracture wings in multiple transverse fracture horizontal wells (MTFHWs). However, microseismic surveys have shown asymmetric hydraulic fracture growth of in successive MTFHWs, and the reason may be elevated stress around a recently fractured well. Dissipating net pressure from the first fracturing treatment may increase the minimum principal stress near created fractures and cause fractures being pumped from an adjacent horizontal well to grow away from the previous fractures and toward lower minimum principal stress on the opposite side of the well. Microseismic maps have shown uneven fracture propagation in a treatment well very near a recently fractured well. Motivated by the microseismic observations, we developed a simple 2-D fracture model to simulate asymmetric fractures which can approximately simulate fracture propagation with a lateral stress barrier. The model indicates a preferred order for hydraulic fracturing in multiple wells that minimizes or avoids asymmetric fracture wings.Item Model for a Shale Gas Formation with Salt-Sealed Natural Fractures(2015-05) Merry, Hoagie; Ehlig-Economides, Christine; Myers, Michael T.; Qin, Guan; Teets, Thomas S.There are reported cases of hydraulically fractured shale wells that exhibit boundary dominated flow in a very short period. This study suggests that dissolution of salt-sealed natural fractures in the shale offers a novel explanation for the early boundary dominated flow. We first discuss a plausible diagenetic history for generation of a salt-sealed natural fracture system in shale gas and how core, log, and conventional test data may behave. We then note that flowback of water with significantly higher salinity than the injected fracture fluid may suggest that the injected low salinity fracturing fluid dissolved salts that sealed an existing natural fracture system. In this scenario, the effective permeability would represent that of the natural fracture system induced by salt dissolution, and the stimulated rock volume would be directly related to the leakoff volume. A simple material balance model tracks salt dissolution by leaked off fracturing fluid and estimates the resulting stimulated rock volume.Item Modeling and Bifurcation Analysis of Oxidative Coupling of Methane(2019-08) Sun, Zhe; Balakotaiah, Vemuri; Harold, Michael P.; Bollini, Praveen; Auchmuty, Giles; Ehlig-Economides, ChristineIn the first part, we present a detailed ignition-extinction analysis of Oxidative Coupling of Methane (OCM) in the gas phase using a global kinetic model for the various oxidation, reforming and dehydrogenation reactions. The kinetic model satisfies the thermodynamic constraints and is validated with literature data as well as new data obtained under near isothermal conditions. It is shown that the type of reactor used has profound influence on the width of the region of multiplicity. Further, the best C₂ yield may be obtained on the ignited branch close to the extinction point where exothermic chemistry dominates or at higher space times or feed temperatures where endothermic chemistry dominates. The extinction locus, which forms the boundary of the region of autothermal operation, is determined as a function of various design and operating variables. In the second part, ignition-extinction analysis of laboratory scale catalytic reactors with heat exchange with the furnace is provided. It is shown that the same volume or mass of catalyst packed in tubes of different diameter and/or with different lengths of inert sections could lead to different types of ignition-extinction behavior as well as product distribution. The impact of tube diameter, heat exchange time, length of inert sections and catalyst dilution on the ignition-extinction behavior is analyzed. Simulations on the impact of heat loss, kinetics and heat/mass dispersion on the region of autothermal operation of lab-scale reactors are also presented. In the third part, ignition-extinction behavior of catalytic OCM with La₂O₃/CaO catalyst in large scale adiabatic reactors is analyzed using a global kinetic model. It is shown that in the homogeneous limit (small particles), the best selectivity of the C₂ products is obtained in the limit of very thin bed (with effective heat and mass Peclet numbers approaching zero). When inter and intra-phase heat and mass transfer gradients are significant (larger particles) so that particle level ignition could occur, selectivity to C₂ product can be enhanced. The impact of catalyst particle properties, inter and intra-particle gradients on conversion and C₂ product selectivity on the ignited branch is analyzed. Finally, some potential autothermal reactor designs for OCM with catalysts of different activity are proposed.Item Modeling of Solid Diverter Particles to Improve the Cluster Efficiency in Hydraulic Fracturing(2023-05-12) Luo, Bo; Wong, George K.; Farouq Ali, S. M.; Soliman, Mohamed Y.; Ehlig-Economides, Christine; Lee, Kyung JaeMulti-stage fracturing in horizontal wells is a crucial technique for boosting production in unconventional reservoirs. Solid diverter particles are often used to enhance cluster stimulation efficiency by promoting uniform fracture propagation. However, the physical processes involved in rock deformation, fluid flow, and particle transport during this technology remain unclear. This dissertation aims to develop an efficient fracturing model with dynamic particle transport to better understand the effectiveness of diversion technology. The developed model utilizes the 3D displacement discontinuity method (DDM), global tip asymptotic solution, and implicit level set algorithm to create a computationally efficient fracturing simulator. The particle transport model uses the ‘wind’ scheme to track nonlinear particle waves in multiple fractures and the Kozeny-Carman model to evaluate the permeability of diverter pack. By treating the dispersed phase as continua, the coupled fracturing model and particle transport model enable the field-scale modeling of the effectiveness of diversion technology in multiple non-parallel fractures. The accuracy of the proposed model is validated through comparisons with analytical and numerical solutions of single fracture, multiple parallel/non-parallel fractures, and 2D particle transport. The evaluated examples demonstrate the feasibility of fracture entrance diversion in a KGD-type fracture model with strong stress interaction at S⁄H= 0.125. However, the PKN-type fracture model with low stiffness and less stress interference (S⁄H= 0.1875) fails to create a stable low permeability diverter pack near the fracture entrance in overgrown fractures. The implementation of a particle swelling and dissolving model promotes successful fluid diversion in the low stiffness (S⁄H= 0.1875) and high stiffness (S⁄H= 0.5) PKN-type fracture models. Besides creating equal unpropped fracture length using the developed model, this study is able to deliver equal propped fracture length by using the proposed slurry pumping schedule. Overall, this dissertation provides a better understanding of the effectiveness of diversion technology in PKN-type fractures. The proposed model can be applied to cases with different fracture stiffness and slurry pumping schedules, providing insights into the optimal use of swelling particles for enhancing cluster stimulation efficiency in unconventional reservoirs. The developed model and insights presented in this dissertation could contribute to more efficient and effective fracture designs in the field.Item Numerical Simulation Study for Analyzing the Factors Affecting Microbial Enhanced Oil Recovery(2021-05) Youzan, Floriane Seka; Lee, Kyung Jae; Ehlig-Economides, Christine; Farouq Ali, S. M.Primary and secondary recovery methods are usually not sufficient to maximize the oil recovery. In many cases, more than 40% of the Oil Initially in Place (OIIP) is left in the reservoir after implementing these recovery methods. To resolve the issue at hand, petroleum engineers have at their disposition a plethora of tertiary recovery methods such as chemical flooding, thermal recovery, and microbial enhanced oil recovery (MEOR). In this study, we propose the use of MEOR: a technique that uses naturally occurring microbes in the reservoir or injected microbes to enhance the oil recovery. This approach is particularly attractive because it is inexpensive and most importantly environmentally friendly. The MEOR process is governed by several mechanisms such as viscosity reduction, wettability alteration, interfacial tension reduction, and other reaction-induced system changes such as pressurization. This study investigates the impact of these mechanisms on the hydrocarbon production by conducting a numerical simulation using the in-house MEOR numerical simulator which is developed from the seed code of TOUGH+ and TOUGH2 family of codes. We conduct a sensitivity analysis to evaluate the impact of factors affecting MEOR to the system responses and production behavior. We investigate the factors as follows: changing relative permeability of oil and water affected by MEOR (to analyze the impact of wettability alteration), changing capillary pressure between oil and water affected by MEOR (to analyze the impact of interfacial tension alteration), and microbial reaction parameters such as yield coefficient of microbes (Y), maximum microbial growth rate (µmax), maximum temperature for microbial growth (Tmax), and microbial death rate (δ) (to analyze the impact of reaction-induced system changes). The system responses include the pressure, temperature, oil viscosity, phase saturations, production rates, and cumulative productions of fluid phases. The simulation results can provide the relative impacts of factors affecting the performance of MEOR, which subsequently can suggest the most important factors to be investigated to reliably predict the improvement of oil production through MEOR. Unlike other MEOR simulator, our in-house simulator models the impact of microbial parameters on fluid production.Item PERFORMANCE ANALYSIS AND THE EFFECTS OF KEY PARAMETERS IN SOLID PARTICLE BEDS(2021-12) Hossain, Nazmul; Metcalfe, Ralph W.; Ostilla-Mónico, Rodolfo; Ehlig-Economides, Christine; Alba, Kamran; Yang, DiFluid-solid particle beds have a broad range of industrial applications as packed and fluidized beds. The particle-particle collision, particle-wall interaction, and virtual mass force which initiates from particle motion influencing neighboring particles make it very difficult to analyze the problem experimentally and numerically. This work is focused on assessing the performance of the existing numerical models for determining minimum fluidization velocity (u_mf), the effects of the key parameters in bed optimization, the turbulence-like behavior initiating from three-dimensionality, quantification of bed performance, and jet-like patterns in uniform inflow. The Eulerian 2D model overestimates pressure drop near fluidization, and thus the U_mf from pressure drop slope cannot be determined accurately. We investigated the 2D TFM (Two-Fluid Model) abnormal pressure drop near minimum fluidization and proposed an Euler number as a more accurate alternative determining u_mf. From our research, the Kinetic Theory of Granular Flow (KTGF) model for particle interaction is more impactful near fluidization, and the drag model is more influential at velocities above u_mf. Our simulations have shown that wall effects on the particle bed including frictional losses and wall-particle collision are the dominant reasons for abnormal pressure drop near minimum fluidization. In an annular fluidized bed, 3D TFM showed that particle size is the most dominant factor in u_mf, followed by the particle bed height or overburden. Bed thickness does not influence u_mf for this type of fluidized bed. Our CFD-DEM simulations showed that there is an increase in recirculation zones for increasing bed thickness to particle ratio. An approach to quantifying the effectiveness of solid particle beds has been proposed with heat transfer between fluid and particles using the CFD-DEM approach. A more efficient capped fluidized bed design has been proposed, and the numerical results show the significant advantage of capped beds over packed, and fluidized beds. We also observed repeating cellular patterns in particle motion for very small size particles in large elongated fluidized beds, and jet-like patterns for uniform inflow under periodic boundary conditions. This will help us in understanding chaotic particle motion and in optimizing bed heat transfer in the future.Item Production Estimation for Hydraulically Fractured Horizontal Wells: A Data-Driven Model-Based Approach(2017-12) Mathur, Sunit; Nikolaou, Michael; Ehlig-Economides, Christine; Marongiu-Porcu, MatteoHydraulic fracturing is essential for oil and gas production from unconventional low-permeability reservoirs. Countless number of variables contribute towards a successfully hydraulic fractured well. Understandings of these variables and its relationships with well production can generate valuable insight which can be used to build better wells for the future. Estimation of well production performance is extremely important to maintain a positive cash flow for any company. Current methodology to relate these variables with production is very tedious and might require expensive and complex simulation models. With the recent advancement in data capturing technologies and emergence of Internet of Things there exist an inordinate opportunity to use the existing data using sophisticated data driven models. Therefore, a framework for building a data driven solution is provided. The model is capable of taking existing wellbore data, completions data, fracture operation data, historical production data and first month production to predict the decline curves of producing wells. This will help in minimizing risks, promote better investment decisions and provide statically backed decline curves in a very short time.Item Reducing the Risk of Gas Leaks into the Ocean Floor Induced by Offshore Production Well Failure in the Gulf of Mexico(2023-12) De Oliveira Souza, Thales; Lee, Kyung Jae; Ehlig-Economides, Christine; Wong, George K.; Farouq Ali, S. M.In the Gulf of Mexico, there are tens of thousands of wells, between producing, shut-in, and abandoned ones. Considering the high number of wells having a risk of leaking gas into the surrounding formations, which may result in gas broaching at the seafloor, a deep understanding of the fate and transport of gas released from damaged wells is of special relevance for hazard assessment and prevention in offshore petroleum operations. This thesis explores a novel strategy to reduce the risk and impact of contaminant releases in the Gulf of Mexico by analyzing the applicability of machine learning technology as a tool to forecast the information regarding a possible broaching in a loss of containment scenario of an offshore well. In this thesis, a conceptual 3-D model of an area representative of the Gulf of Mexico was used to simulate the geosystem behavior for different scenarios of subsurface containment failure. A total of 20 heterogeneous permeability fields were initially used in the modeling of gas broaching. For each of the 20 heterogeneous permeability fields, this work tested 13 different locations where a hypothetical vertical well would be placed, and then a leakage point due to failure would lead to gas escaping from containment. The TOUGH+HYDRATE code for the simulation of system behavior in hydrate-bearing media was selected to be used in this work. For each simulation, we compiled the broaching day and location, the hydrate mass generated in the system until broaching day and at the end of the simulation, and the total released CH4 in gas phase in the system until broaching day and at the end of the simulation. The data generated from the different scenarios of well containment failure were compiled to be used as input data for training the Artificial Neural Network (ANN) models. We trained six networks to be data-driven models for the prediction of the different outputs. The data-driven models to predict the gas broaching time and location were created as functions of the cartesian coordinates of the leakage point and the permeability of all blocks in the vertical column above the leakage. The data-driven models to predict the hydrate mass and gas phase CH4 volume on broaching day and at the end of the simulation were created as functions of the gas broaching time and gas broaching location. From the six ANN models created and trained, four of them were able to find a strong or very strong correlation between the input and output features during training and when tested with the full dataset. We used a new permeability model to generate a new set of input and output parameters for measuring the network’s generalization. The new dataset was applied to the chosen ANN models predicting broaching location, broaching time, hydrate mass generated in the system at the end of the simulation, and the gas phase CH4 volume in the system at the end of the simulation. When presented with the validation dataset, the outstanding performance of these ANN models indicated their reliability in the prediction of the broaching parameters, and the significant generalization capability of the models.Item Shale Gas Production Forecasting using Reservoir Simulation with Hydraulic Fracture Mapping(2019-05) Xu, Ben; Qin, Guan; Thakur, Ganesh C.; Ehlig-Economides, Christine; Nikolaou, Michael; Lee, Kyung JaeThis dissertation presented a hybrid Embedded Fracture Dual Porosity (EF-DP) model for shale gas production forecasting. We presented a new correlation between the microseismic magnitude and the shape factor coefficients in the classic dual-porosity model accompany a procedure to calibrate this coefficient with real production data. The novel contribution was the employment of the shape factor in the dual-porosity model to characterize a relatively complex small scale fracture network, which numerically integrates with the large scale fractures geometry in the EDFM model to forecast shale gas well production. A constrained result of using microseismic data to measure the length and direction of the large scale fractures was put into the embedded discrete fracture model (EDFM) to integrate the large scale fracture into a corner point grid. The EF-DP model considered stimulation data such as total fluid volume for hydraulic fracturing, flow rate, wellhead pressure, sand concentration, and proppant size. To verify the credibility of this model, we performed two sets of parameter sensitivity analyses for the large scale fractures and the small scale fractures. We used two sets of real-world shale gas production data for history matching and successfully used the EFDP model to quantify analysis the impact of frac-hit on a shale gas producing well. Parameter sensitivity analysis confirmed that enhanced small scale fracture permeability could effectively increase production, mainly by strengthening far-field reservoir drainage volume. According to the application results, we found that the EFDP model was effectively and accurately predict shale gas production, and quantitatively evaluate the impact of frachit between multiple wells. The refracturing candidate selection results guided further well completion strategy improvement. Microseismic-based approaches provide a robust fracture network model, further reservoir modeling calibration and simulation studies can reveal invaluable information about the active stimulated zone.Item Simultaneous Multiple Plane to Plane Waterflooding in Fractured Tight Reservoirs(2017-12) Bhargav, Bhaskar Jyoti; Ehlig-Economides, Christine; Thakur, Ganesh C.; Soliman, Mohamed Y.Waterflooding is common in conventional reservoirs, but efforts to apply waterflooding to unconventional tight oil formations have not met much success. The purpose of this research is to investigate the effectiveness of a novel 3-well pattern using horizontal wells (one injector and two producers, or one producer and two injectors) with multiple transverse hydraulic fractures nested to create arrays of plane-to-plane injector-producer waterflood displacements between propped hydraulic fractures. The model for each plane-to-plane displacement uses pseudorelative permeability functions to account for conductive secondary fracture networks induced by hydraulic fracturing of the horizontal wells. Each pseudorelative permeability function is computed using inputs for the matrix and secondary fracture porosity and absolute permeability values, and matrix and secondary fracture relative permeability curves generated from Corey functions. To represent heterogeneity, input parameters are randomly generated, and the computed pseudorelative permeability functions are fit using Corey function parameters. Then we apply the Buckley-Leverett model for each displacement using the pseudorelative permeability curves. Finally, the pattern waterflood model accounts for the simultaneous multiple displacements using constant pressure well conditions and assuming minimal pressure losses along the wells and in the created hydraulic fractures. Sensitivity studies have been carried out on a sample pattern with a smaller number of waterflood units undergoing plane-to-plane displacement, while full-scale simulation of a pattern with 408 waterflood units has been carried out to study the effectiveness of waterflooding in an unconventional reservoir using the proposed pattern. The study showed that pattern recovery factors increased for reduced secondary fracture porosity, and decreasing the hydraulic fracture spacing accelerated recovery. Further, rapid water breakthrough through in any individual displacement could short-circuit the displacement, and multiple short-circuits can cause poor pattern recovery efficiency. The proposed 3-well pattern offers a way to avoid well to well short-circuiting through propped fractures and enables a large number of simultaneous displacements. This work evaluates both the potential recovery efficiency increase and the potential risk and uncertainty related to the presence of induced secondary fractures.