There is a vast worldwide consumption of petroleum hydrocarbons and accidental release in to the environment is common. For example petroleum forecourt retail outlets have 'interceptors' to prevent release of hydrocarbons into the environment. The aim of this study was to investigate options for in-situ bioremediation of the hydrocarbon substrates within these 'interceptors' in a laboratory model. The initial studies on bioremediation were undertaken with diesel as the substrate. It was shown that the addition of nitrogen and phosphorus to the system increased hydrocarbon mineralisation by a factor of 16, resulting in increased carbon dioxide evolution. There was strong evidence indicating that nitrogen and phosphorus were the limiting factor for hydrocarbon metabolism in this aqueous system. Trichoderma harzianum and a soil bacterial isolate LFC D1 FI were assessed and shown to degrade hexadecane and pristane. The positive affect of adding a cosubstrate was evident in flask studies; the rates of degradation by LFC D1 FI and T. harzianum were approximately doubled and tripled respectively in the presence of glucose compared to treatments without glucose. Previous attention has focused on the ability of Phanerochaete chrysosporium to degrade polycyclic aromatic hydrocarbons; in this study the degradation of aliphatics was investigated. Spores from P. chrysosporium induced on the hydrocarbon substrate were found to be necessary to degrade hexadecane. Pseudomonas putida was unable to grow in liquid media containing hydrocarbons, however on solid media and in an aqueous environment containing acid-washed sand, degradation of hydrocarbons was evident, hi the presence of sand P. putida degraded both hexadecane and pristane by 70% of the initial concentration added; in the absence of sand no degradation in the aqueous system was seen. This suggests surface attachment plays an important role in hydrocarbon degradation by P. putida. The attachment and use of the sessile P. putida in aliphatic hydrocarbon degradation is discussed.

<p> Rock fracture mechanics theories have been used for more than 50 years in the oil and gas industry. Fracture mechanics is about understanding what will happen to the rocks in the subsurface when subjected to fracture stress. Much of what is used in hydraulic fracturing theory and design was developed by other engineering disciplines many years ago. However, rock formations often cannot be treated as isotropic and homogeneous. These assumptions affect the calculation of in-situ stresses which are important for designing hydraulic fracture and knowing the stability of wellbore. A Geomechanical model is built to investigate these problems and to predict the alterations and changes of the Geomechanical properties of the reservoir. </p><p> After the reservoir characterization and determination of the magnitude and direction of in&ndash;situ stresses, our next step is to prepare a 3-D Geomechanical model in ANSYS Workbench. Elastic anisotropy of the formation is included in the 3-D numerical models. The model will represent the Bakken Formation, having all its properties. After preparing a mesh for this model to carry out further studies, we apply stresses to the model so that it represents the depth at which the Bakken Formation is encountered while keeping the drilling conditions in mind. We analyze wellbore stability and predict wellbore behavior under stress alteration caused by drilling. </p><p>

<p> In shale gas development, the mechanical properties of shale are crucial in hydraulic fracture propagation, wellbore stability, and the productivity of a shale gas wells. In this dissertation, acoustic velocity tests, uniaxial compressive tests, and Brazilian tensile tests were conducted on Eagle Ford and Mancos shale to investigate gas shale mechanical properties, including dynamic mechanial properties and static mechanical properties (compressive and tensile mechanical properties). Water content, mineralogy, and anisotropic effects on shale mechanical properties were analyzed. </p><p> Ultrasonic velocity measurements were performed on Eagle Ford shale samples. Dynaimic elastic properties were determined according to the compressive- and shear-wave vleocities. The results showed that both P- and S-wave velocities increase as confining pressure increases. Horizontal elastic modulus, vertical elastic modulus, and shear modulus increase with increasing confining pressure. While horizontal and vertical Poisson&rsquo;s ratio exhibited more or less invariant with confining pressure. Transverse isotropy is an appropriate model to characterize Eagle Ford gas shale. Elastic properties of Eagle Ford shale are direction-dependent. Horizontal Young&rsquo;s modulus is higher than vertical Young&rsquo;s modulus and horizontal Poisson&rsquo;s ratio is higher than vertical Poisson&rsquo;s ratio. Increasing water content reduce Young&rsquo;s modulus and shear modulus significantly. Induced water can make the shale softer. Water increase Eagle Ford shale&rsquo;s anisotropies. Both P- and S- wave velocities decrease with increasing of TOC and clay content. Dynamic Young&rsquo;s modulus, shear modulus, and bulk modulus vary inversely with TOC and clay. Poisson&rsquo;s ratio does not correlate with TOC or clay content for these test samples. </p><p> Static mechanical properties were investigated by conducting uniaxial compressive tests and Brazilian tensile tests on Eagle Ford and Mancos shale samples. A new method was developed to analyze tensile elastic behavior of materials. The imbibed water significantly reduces the uniaxial compressive strength. Young&rsquo;s modulus of wet samples is lower for corresponding dry samples. The maximum Young&rsquo;s modulus decrease is up to about 70%. The imbibed water makes the shale softer. Poisson&rsquo;s ratio increase with water content. Bedding plane/laminations have a significant impact on Eagle Ford indirect tensile strength, but not on Mancos shale. The imbibed water significantly reduces tensile strength and tensile Young&rsquo;s modulus, but increase tensile Poisson&rsquo;s ratio. Low clay content in the Eagle Ford shale (around 6%) and high clay content in the Mancos (around 22%) might be the explanation for the overall lower tensile strength of the Mancos than Eagle Ford shale. </p><p> Static and dynamic elastic properties of Eagle Ford shale samples are compared. Static Young&rsquo;s modululs is lower than dynamic Young&rsquo;s modulus. There is no strong correlations between static and dynamic Poisson&rsquo;s ratio observed for the tested samples. The relationship of compressive and tensile mechanical properties of Eagle Ford shale are investigated. Tensile Young&rsquo;s modululs is 0.76 to 0.98 times lower than corresponding compressive Young&rsquo;s modulus. There is either no strong correlations between tensile and compressive Poisson&rsquo;s ratio observed for the tested samples. </p><p> Water weaken mechanism was analyzed. Three potentially major weakening mechanisms&mdash;chemical effects, water clay interaction, and capillary pressure increase&mdash;were discussed in detail.</p><p>

<p> Reliability of equipment during well construction is necessary. Failure of components increases non-productive time and may cause injuries or loss of life. The jar is a component used in well construction, usually as part of the drill string to free stuck pipe or during fishing. It is subject to impact loads due to the hammering and tensile loads caused due to hook loads on the drill string. In this work, a root cause is failure analysis of failed component. The failure is different from all the other cases due to the reason that most of the time the component collapses and rather fails completely. The main objective is to find the root cause of failure. The visual inspection indicates signs of tensile and brittle failure. The scanning electron microscope analyses show evidence of fatigue: the classic beach mark striations. The presence of aluminum and voids in the section show that the material used for manufacture was of low quality. In this paper, efforts are made to provide recommendations to the company that rents these jars. The various causes of failure mentioned can be useful to have better understanding and control of the manufacturing process, improved instructions for the use of the jar, improve the overall reliability of the component, and use it for well construction with the safety of personnel and minimum non-productive time. </p><p>

<p> The use of surfactants to alter the reservoir hydrocarbons affinity towards the injection fluids such as water is an effective method to increase the oil production on depleted reservoirs. However, the actual field use of this technique has been limited by major economical complications generated by the unaccounted loss of surfactants to the reservoir rock pores. Reducing the adsorption of surfactants to the reservoir rock can be achieved through the addition of sacrificial elements to the injection slug. Sacrificial elements such as polymers can engage in a competitive behavior with surfactants for the adsorption to the reservoir rock surface. This thesis work focuses on the simulation of the dynamic adsorption of surfactants when sacrificial agents, such as polymers, are injected on a 3-D field scale reservoir model. </p><p> The purpose of this thesis research is to determine if the new in model for streamline particle flow simulation developed in-house for academic purposes can accurately predict the surfactant and polymer adsorption/desorption to the reservoir pores. Based on laboratory experiment data from publications, the SL simulator will model the surfactant and polymer adsorption on a 3-D heterogeneous reservoir in order to determine if the surfactant adsorption could be reduced when polymers are injected as sacrificial agents on a chemical mixture or sequential profile. The simulation output displays promising results, since it accurately models the effects generated on the surfactant dynamic adsorption caused by the injection of sacrificial agents such as polymers. This 3-D SL simulator could be used for field applications to obtain better predictions about the dynamic adsorption of surfactants, which would increase the efficiency of surfactant flooding operations.</p><p>

<p> Hydraulic fracturing is a commonly used practice in stimulation treatment, especially in low-permeability formation. The fracture complexity usually took place in relation to the interaction between fractures and natural rock fabrics. Despite many studies regarding the production simulation, diagnostic methods, and mathematical models about fracture complexity, research about the local complexity development is still needed for optimized stimulation design. Aiming to predict the local complexity development and stimulation performance, a hierarchy model is designed to make the problem more tractable, and a corresponding mathematical model is developed for numerical simulation. A case study is provided, and the comparison with the result of micro-seismic mapping indicates much discrepancy between field data and simulated result. Considering the many limitations of the model, the discrepancy is tolerable and acceptable. According to the sensitivity analysis, a high injection rate could serve to increase fracture complexity while reducing the maximum length of fractures. The sensitivity analyses regarding bottom-hole net pressure show a weak relationship between the fracture complexity and the bottom-hole net pressure, but a high injection pressure or low in-situ stress can serve to enhance the stimulation performance by increasing the maximum length of fractures. Sensitivity analyses for fluid properties indicate that using the high-viscosity fracturing fluid can add to the local complexity of fractures and reduce the maximum length of fractures, while fluid density has little to do with the fracture complexity and stimulation performance. The parametric study regarding rock surface energy indicates little effect of surface energy of different shale rocks on changing the local fracture complexity and stimulation performance.</p><p>

Data driven modeling (DDM) techniques implement machine learning (ML) to analyze data and discover connections without explicit knowledge of the physical behavior. Recent improvements in technology and computational power have increased interest in the application of DDM in petroleum industry. Recovery process evaluation using numerical reservoir simulators are always costly, time consuming, computational intensive with many assumptions and uncertainty involved. In this thesis, DDM have been adopted as an alternative tool to predict production performance under waterflooding which is one of the most important techniques for improving oil recovery. A synthetic waterflooding dataset including production profile, operational parameters, reservoir properties and well locations is constructed using the numerical reservoir simulator. Exploratory data analysis provides several insights into the non-intuitive factors in building the reservoir model. K-means clustering analysis is performed to identify internal groupings among producers. Artificial neural network (ANN) and support vector machine (SVM), particularly support vector regression (SVR), are used to decipher the nonlinear relationships between input attributes and waterflooding production. The trained models are subsequently used to predict cumulative oil and watercut on the unseen samples. Clustering analysis reveal that distance to the free water level has a dominant effect. The cluster that has the smallest average distance to FWL tends to have the highest watercut and lowest cumulative oil compared with the simulation results. Clustering results also indicates that the clustering assignment is controlled by the interplay among input attributes characterizing reservoir properties and relative well locations. Good agreements between predicted outputs from models and simulation targets present the satisfactory generalization performance and predictive capabilities of ANN and SVR methods. ANN model with one output provides the most accurate prediction result on the test data. ANN model with two outputs reveals the robustness of this approach. SVR models provide similar but slightly worse forecast than ANN models. No previous work studied on the application of SVM on waterflooding performance prediction. Results in this study verify its acceptability and applicability. Proposed methodologies in this thesis study can be utilized as a surrogate or complementary model to analyze and predict recovery process in other reservoirs fast and efficiently.

The immiscible displacement of oil by water in a petroleum reservoir has been simulated in the laboratory using a consolidated porous medium constructed out of silica sand particles. Four distinct displacement flow modes were employed, namely horizontal, vertical upward, vertical downward, and transverse. Experiments were carried out by displacing the oil phase (heavy paraffin oil) by the aqueous phase (dyed glycerol solution) at different oil/water viscosity ratios, at different flow rates, and in the presence and absence of connate water (connate water is the name given to the very small amount of water that occurs naturally in petroleum reservoirs). The objective of this study was to investigate the effects of viscosity ratio, flow rate, and flow mode on the oil recovery efficiency. In the absence of connate water, a decrease in the oil recovery is observed when the oil/water viscosity ratio increases for all four flow modes but the displacement patterns are different for each flow mode. In the presence of connate water, the dependence of oil recovery on viscosity ratio is similar although in this case the displacement patterns are almost indistinguishable for the four different flow modes on account of coalescence of the connate water phase with the displacing aqueous phase. Without connate water, the highest recovery is obtained in the vertical upward mode where the buoyancy forces stabilize the displacement process. Conversely, in the vertical downward flow mode, the instability promoted by gravity leads to a low recovery. Comparison of the results obtained with and without connate water shows that connate water has a negative effect on the recovery and, moreover, that the synergistic effect between the viscosity ratio and the connate water reduces the oil recovery efficiency significantly.

When a higher-viscosity fluid is displaced by a lower-viscosity fluid in a porous medium, the displacing fluid tends to channel through the paths of lesser hydrodynamic resistance, thereby forming pronounced "fingers". The effects of buoyancy (gravity) forces on the stability of such displacement processes are of considerable importance in many practical situations, especially during the recovery of oil from underground reservoirs, or during the clean-up of subterranean toxic chemical spills, by means of aqueous fluid injection. The present work is confined to the former (i.e., oil recovery) situation. In this work, the effects of buoyancy forces on immiscible water/oil displacement processes and miscible oil/oil displacement processes were studied for linear flows occurring in a two-dimensional, consolidated, transparent porous medium aligned in either the vertical or horizontal plane. Experiments were performed using three different flow modes, namely horizontal, vertical-upwards and vertical-downwards. A wide range of injection flow rates were employed in order to elucidate the relative effects of buoyancy forces, viscous forces and capillary forces. For each displacement, the breakthrough condition was measured, and photographs of the evolving fingering patterns were taken. A mathematical analysis of the observed displacement phenomena produced an analytical relationship expressing the macroscopic water saturation profile as a function of dimensionless distance. The horizontal flow mode was employed as the reference condition for the prediction of the oil recovery efficiency in the two vertical flow modes, since buoyancy forces can be effectively neglected in horizontal flow. A reliable technique for measuring the saturation profile from the displacement photographs was developed in order to interpret the experimental data. Good agreement between the theoretical and experimental results was obtained, thereby permitting a reliable quantitative prediction of the effects of buoyancy forces on oil recovery during immiscible water/oil displacement processes. The extent to which the viscosity ratio, interfacial tension, and flow rate influenced the relative effects of the buoyancy forces will be discussed in relation to measured breakthrough times and oil recoveries. Also, the instability theory of the displacement will be discussed. It is evident from the results obtained that buoyancy forces are capable of exerting very significant effects on the stability of liquid-liquid displacement processes occurring in porous media, on the formation of fingers, and on the ultimate recovery efficiency during practical oil recovery processes involving aqueous fluid injection.

Swarms, of diabase dikes have been reported in all Provinces of the Precambrian Shield. One of these is the Buckingham swarm which extends into the region of the Gatineau Park. A fresh exposure of one of these dikes was sampled to study ids petrographic and chemical characteristics and any variations which might reflect the nature of its formation. The physical and chemical characteristics of the dike compare closely to those of Hawaiian tholeiitic basalts, and the sub-ophitic texture of this dike resembles that of typical diabase dikes. The dike appears to be a member of a swarm of diabase dikes of probable Ordovician age, and are located in the Grenville province of the Canadian Shield. Some variations in composition exist across the dike. (a) Mafic minerals decrease in quantity inward while plagioclase increases inward. (b) Grain size graphs plot in the shape of a bell curve, rather than parabolic. (c) The characteristic sub-ophitic texture is replaced by porphyritic texture in the contact samples. (d) An content of plagioclase decreases inward. (e) Silica content of bulk rocks decreases outward. (f) Rock compositions appear to have erratic variation in the zones near the contacts. The observed variation in texture and chemical composition within the study dike may be attributed to a combination of factors including; contamination, secondary alteration, and some form of differentiation.