Download or read book In Situ Investigations of Wettability and Pore scale Displacements During Two and Three phase Flow in Oil wet Carbonates written by Ziqiang Qin and published by . This book was released on 2021 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preferentially oil-wet characteristics of carbonate reservoir rocks hinder oil recovery due to conventional waterflooding. The remaining oil in these reservoirs is the target of enhanced oil recovery (EOR) techniques such as low-salinity waterflooding (LSWF), immiscible/near-miscible gas injection, Water-Alternating-Gas (WAG) flooding, and carbonated water injection (CWI). An improved fundamental understanding of wettability and displacement mechanisms governing multiphase flow behavior in oil-wet carbonates is critical to ensure the success of these EOR schemes in the field. However, there is a dearth of literature focused on the displacement physics of such EOR processes at the pore scale. To fill in these research gaps, a series of miniature core-flooding experiments were performed in oil-wet carbonates at elevated temperature and pressure conditions, using a three-phase core-flooding system integrated with a high-resolution x-ray micro-CT scanner. Our observations indicated that higher temperature and lower initial water saturation established greater equilibrium in situ oil-brine contact angles during dynamic aging-induced wettability alteration process. For LSWF, wettability reversal towards neutral-wetness and the consequent reduction in threshold brine pressure required for the fluid to invade medium-sized oil-filled pores led to a higher oil recovery than that of high-salinity waterflooding. Under tertiary immiscible gas injection scheme, gas-to-oil-to-brine double displacements were the main pore-scale events responsible for the enhancement in oil production. During this process, the greater was the degree of oil-wetness of the rock, the larger became the additional oil recovery. Furthermore, WAG flooding significantly increased the displacement efficiency of both gas and brine phases because of the shield effect of the trapped gas ganglia. In the first WAG cycle, oil was produced through a series of direct and double displacements. Multiple displacements started taking place and further contributed to oil recovery as more WAG cycles were implemented. As for the CWI scheme, we found that pore-scale mechanisms governing oil mobilization included decrease in the threshold brine pressure of displacements due to wettability reversal, swelling and coalescence of oil ganglia, and brine flow diversion. After CWI, as the in situ CO2 exsolution progressed due to depressurization, gas bubbles preferably formed, grew, and resided in larger pores. The synergistic effects of spreading oil layers and double displacements prompted the isolated oil globules to coalesce and facilitated the oil mobilization. Finally, in near-miscible supercritical CO2 (scCO2) injection scheme, we observed a distinct wettability state where the wetting preference of the solid to scCO2, oil, and brine phases was similar. Consequently, pore sizes neither dictated any preferential invasion order nor restricted the displacement efficiency. Furthermore, we identified a new type of spreading system where spreading oil layers formed but did not exist globally across the pore space between the scCO2 and brine phases. In this experiment, the frequencies of double and multiple displacements were much higher than those observed during N2 injection in oil-wet systems. The interplay of scCO2-oil miscibility, the distinctive wettability state, favorable fluid connectivity, and frequent double/multiple displacements resulted in an exceptional displacement efficiency.

Download or read book Pore scale Characterization of Wettability and Displacement Mechanisms During Oil Mobilization Due to Waterflood based Oil Recovery Schemes written by Mahdi Khishvand and published by . This book was released on 2018 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of an extensive pore-scale experimental study of trapping of oil in topologically disordered naturally-occurring pore spaces. A unique miniature core-flooding system is built and then integrated with a high-resolution micro-computed tomography (micro-CT) scanner to create a new experimental platform, which enables us to conduct flow experiments on a small rock specimen, nominally 5-mm-diameter, at conditions representative of subsurface reservoirs while the sample is being imaged. We develop robust experimental procedures and state-of-the-art image analysis techniques to characterize in-situ wettability and accurately map the spatial distribution of fluid phases at the pore level during various multiphase flow phenomena. This indeed has the possibility to transform our understanding of these important flow processes and allows us to have a much more effective way of designing enhanced oil recovery schemes deployed in a wide range of geological systems. Below, we list four key applications of this new approach, which are achieved under this study. These include: (1) In-situ characterization of wettability and pore-scale displacement mechanisms; (2) Micro-scale investigation of the effects of flow rate on nonwetting phase trapping; (3) Systematic examination of the impact of brine salinity on residual phase saturation; and (4) Experimental study of the remobilization of trapped oil ganglia associated with CO2 exsolution during carbonated water injection. Initially, we perform several two-phase experiments on Berea sandstone core samples and characterize contact angle hysteresis for various fluid pairs. Afterward, we carry out a three-phase experiment including a secondary gas injection followed by a waterflood and then an oilflood. We generate in-situ oil-water, gas-water, and gas-oil contact angle distributions during each stage of this flow experiment and compare them with the two-phase counterparts to develop new insights into relevant complex displacement mechanisms. The results indicate that, during gas injection, the majority of displacements involving oil and water are oil-to-water events. It is observed that, during the waterflood, both oil-to-gas and gas-to-oil displacement events take place. However, the relative frequency of the former is greater. For the oilflood, gas-water interfaces only slightly hinge in pore elements. Pore-scale fluid occupancy maps and the Bartell-Osterhoff constraint verify the above-mentioned findings. Secondly we conduct a pore-scale experimental study of residual trapping on consolidated water-wet sandstone and carbonate rock samples. We investigate how the changes in wetting phase flow rate impacts pore-scale trapping of the nonwetting phase as well as size and distribution of its disconnected globules. The results show that with increase in imbibition flow rate, the residual oil saturation reduces from 0.46 to 0.20 in Bemtheimer sandstone and from 0.46 to 0.28 in Gambier limestone. The reduction is believed to be caused by alteration of the order in which pore-scale displacements took place during imbibition. We use pore-scale displacement mechanisms, in-situ wettability characteristics, and pore size distribution information to explain the observed capillary desaturation trends. Furthermore, we explore that the volume of individual trapped oil globules decreases at higher brine flow rates. Moreover, it is found that the pore space in the limestone sample is considerably altered through matrix dissolution at extremely high brine flow rates. Imbibition in the altered pore space produces lower residual oil saturation (from 0.28 to 0.22) and significantly different distribution of trapped oil globules. Thirdly, a series of micro- and core-scale flow experiments are carried out on mixed-wet reservoir sandstone core samples at elevated temperature and pressure conditions to examine the impact of injection brine salinity on oil recovery and accentuate governing displacement mechanisms. Individual core samples are cut from a preserved reservoir whole core, saturated to establish initial reservoir fluid saturation conditions, and subsequently waterflooded with low- and high-salinity brines. In addition to the preserved experiments, several samples are cleaned, subjected to a wettability restoration process, and then used for waterflooding experiments. The results indicate approximate waterflood residual oil saturations (S[subscript]orw) of 0.25 and 0.39 for LSWF and HSWF, respectively. These observations highlight the remarkably superior performance of LSWF compared to that of HSWF. LSWF tests show a more prolonged oil recovery response than HSWF. The findings provide direct evidence that LSWF also causes a wettability alteration toward increasing water-wetness – due to limited release of mixed-wet clay particles and multi-component ion exchange, whereas contact angles measured during HSWF remain unchanged. It is observed that the reduction in oil-water contact angles lowers the threshold water pressure needed to displace oil from some medium-sized pore elements and enhances oil recovery during LSWF. Finally, we present the results of a micro-scale three-phase experimental study, using a spreading fluid system, of carbonated water injection and subsequent CO2 exsolution, as a consequence of pressure depletion, that lead to recovery of a significant fraction of trapped oil. Micro-CT visualization of pore occupancy show that the gradual increase in the pressure drop leads to exsolution of CO2, internal gas drive, mobilization of oil ganglia, and a notable reduction in waterflood residual oil saturation. When contacted by CO2, oil globules form thick spreading layers sandwiched between brine (in the corners) and gas (in the center of pores) and are displaced toward the outlet along with moving gas clusters. We observe significant re-connection of trapped oil globules due to oil layer formation during early stages of CWI. The oil layers stay stable until the very late stages of gas exsolution.

Download or read book Multiphase Flow in Permeable Media written by Martin J. Blunt and published by Cambridge University Press. This book was released on 2017-02-16 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a fundamental description of multiphase fluid flow through porous rock, based on understanding movement at the pore, or microscopic, scale.

Download or read book A Geoscientist s Guide to Petrophysics written by Bernard Zinszner and published by Editions TECHNIP. This book was released on 2007 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geoscientists and Engineers taking an interest in Petrophysics, are struck by the contrasting treatment of the Physics Aspects and the Geology Aspects. If we are to scale up isolated petrophysical observations to an entire oil reservoir or an aquifer, it is essential to implement the powerful extrapolation tool of geological interpretation. This is clearly based on a good understanding of the relations between the petrophysical parameters studied and the petrological characteristics of the rock considered. The book is divided into two sections of different size. The first section (by far the largest) describes the various petrophysical properties of rocks. Each property is defined, limiting the mathematical formulation to the strict minimum but emphasising the geometrical and therefore petrological parameters governing this property. The second section concentrates on methodological problems and concerns, above all, the representativeness of the measurements and the size effects. The notions of Representative Elementary Volume, Homogeneity, Anisotropy, RockType, etc. provide a better understanding of the problems of up-scaling (Plug, Core, Log Analysis, Well Test). Lastly, we provide a description of several Porous Network investigation methods:Thin section, Pore Cast, Visualization of capillary properties, X-ray tomography.

Download or read book Pore Scale Modeling of Multiphase Flow in Heterogeneously Wet Media written by Rahul Verma (Ph. D. in petroleum engineering) and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pore scale simulation has recently become an important tool for understanding multiphase flow behavior in porous materials. It enables detailed mechanistic studies of upscaled flow parameters such as capillary-pressure saturation curves, residual saturation of each phase, and relative permeability. However, direct modeling of multiphase flow given the complex solid surfaces in a porous medium is a non-trivial problem. In this work, we develop a new quasi-static, variational level set formulation capable of handling trapped phases as well as wettability. We extend our previous work [1, 2] for simple geometries, and develop a new parallelized code enabling application of the method in larger geometries. We compare our model results against several experimental and semi-analytical datasets. The model is first applied to both homogeneous and heterogeneously wet rhomboidal pores, and compared against semi-analytical solutions derived by Mason and Morrow [3]. Subsequently, we focus on a quasi-2D micromodel study of fluid-fluid displacement for different wettabilities, which is quantified using the displacement efficiency and fractal dimension of the displacement patterns [4]. We then study classic experiments by Haines [5] and Leverett [6] for measuring the capillary pressure and relative permeability curves in sphere packs and sandpacks, respectively. We match trends in trapping in sandpacks during drainage/imbibition experiments by Pentland et al. [7], and also compare it against predictions by several other pore-scale models. Finally, we confirm the pore-scale hypothesis suggested by DiCarlo et al. [8] for explaining experimental observations of three-phase relative permeability of the intermediate-wet phase in sandpack experiments. For these three-phase experiments, we propose an approximation based on finding phases trapped between constant curvature surfaces, using two-phase simulations. We demonstrate the versatility of our methods by applying it to these disparate experimental datasets, and suggest future applications of our work

Download or read book Chemical Enhanced Oil Recovery written by Patrizio Raffa and published by Walter de Gruyter GmbH & Co KG. This book was released on 2019-07-22 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims at presenting, describing, and summarizing the latest advances in polymer flooding regarding the chemical synthesis of the EOR agents and the numerical simulation of compositional models in porous media, including a description of the possible applications of nanotechnology acting as a booster of traditional chemical EOR processes. A large part of the world economy depends nowadays on non-renewable energy sources, most of them of fossil origin. Though the search for and the development of newer, greener, and more sustainable sources have been going on for the last decades, humanity is still fossil-fuel dependent. Primary and secondary oil recovery techniques merely produce up to a half of the Original Oil In Place. Enhanced Oil Recovery (EOR) processes are aimed at further increasing this value. Among these, chemical EOR techniques (including polymer flooding) present a great potential in low- and medium-viscosity oilfields. • Describes recent advances in chemical enhanced oil recovery. • Contains detailed description of polymer flooding and nanotechnology as promising boosting tools for EOR. • Includes both experimental and theoretical studies. About the Authors Patrizio Raffa is Assistant Professor at the University of Groningen. He focuses on design and synthesis of new polymeric materials optimized for industrial applications such as EOR, coatings and smart materials. He (co)authored about 40 articles in peer reviewed journals. Pablo Druetta works as lecturer at the University of Groningen (RUG) and as engineering consultant. He received his Ph.D. from RUG in 2018 and has been teaching at a graduate level for 15 years. His research focus lies on computational fluid dynamics (CFD).

Download or read book Pore scale Investigation of Wettability Effects on Two phase Flow in Porous Media written by Harris Rabbani and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Relative Permeability Of Petroleum Reservoirs written by M.M. Honarpour and published by CRC Press. This book was released on 2018-01-18 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book enables petroleum reservoir engineers to predict the flow of fluids within a hydrocarbon deposit. Laboratory techniques are described for both steady-state and unsteady state measurements, and the calculation of relative permeability from field data is illustrated. A discussion of techniques for determing wettability is included, along with theoretical and empirical methods for the calculation of relative permeability, and prediction techniques. Contents include: Measurement of Rock Relative Permeability; Two-Phase Relative Permeability; Factors Affecting Two-Phase Relative Permeability; Three-Phase Relative Permeability; and Index.

Download or read book Pore scale Dynamics of Immiscible Two phase Flow on Porous and Fractured Media written by Qingqing Gu and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pore-scale investigations of immiscible two-phase flow displacement dynamics in porous media provides crucial information to natural and industrial processes such as nonaqueous phase liquid (NAPL) contamination of groundwater, carbon dioxide injection and storage, and enhanced oil recovery (EOR) operations. It has the potential to transform our understanding of multiphase flow processes, to improve oil and gas recovery efficiency, and to facilitate safe carbon dioxide storage. However, the modelled porespace geometry is naturally complex for these fields of application. For directly simulating multiphase flow within the complex structure, the most widely-used approach isthe lattice Boltzmann method (LBM).In this thesis, the implementation of the state-of-the-art colour gradient two-phase LBMhas been validated against the theoretical solution for capillary filling, and analytical solutions for relative permeabilities in a cocurrent flow in a 2D channel. Then it is employed to investigate the effects of interfacial tension, wettability, and the viscosity ratio on displacement of one fluid by another immiscible fluid in a two-dimensional(2D) Berea sandstone.

Download or read book Fundamentals and Practical Aspects of Gas Injection written by Reza Azin and published by Springer Nature. This book was released on 2021-07-28 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers different aspects of gas injection, from the classic pressure maintenance operation to enhanced oil recovery (EOR), underground gas storage (UGS), and carbon capture and storage (CCS). The authors detail the unique characteristics and specific criteria of each application, including: material balance equations phase behaviour reservoir engineering well design operating aspects surface facilities environmental issues Examples, data, and simulation codes are provided to enable the reader to gain an in-depth understanding of these applications. Fundamentals and Practical Aspects of Gas Injection will be of use to practising engineers in the fields of reservoir engineering, and enhanced oil recovery. It will also be of interest to researchers, academics, and graduate students working in the field of petroleum engineering.

Download or read book Wettability and Oil Recovery by Imbibition and Viscous Displacement from Fractured and Heterogeneous Carbonates written by Jill Buckley and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: About one-half of U.S. oil reserves are held in carbonate formations. The remaining oil in carbonate reservoirs is regarded as the major domestic target for improved oil recovery. Carbonate reservoirs are often fractured and have great complexity even at the core scale. Formation evaluation and prediction is often subject to great uncertainty. This study addresses quantification of crude oil/brine/rock interactions and the impact of reservoir heterogeneity on oil recovery by spontaneous imbibition and viscous displacement from pore to field scale. Wettability-alteration characteristics of crude oils were measured at calcite and dolomite surfaces and related to the properties of the crude oils through asphaltene content, acid and base numbers, and refractive index. Oil recovery was investigated for a selection of limestones and dolomites that cover over three orders of magnitude in permeability and a factor of four variation in porosity. Wettability control was achieved by adsorption from crude oils obtained from producing carbonate reservoirs. The induced wettability states were compared with those measured for reservoir cores. The prepared cores were used to investigate oil recovery by spontaneous imbibition and viscous displacement. The results of imbibition tests were used in wettability characterization and to develop mass transfer functions for application in reservoir simulation of fractured carbonates. Studies of viscous displacement in carbonates focused on the unexpected but repeatedly observed sensitivity of oil recovery to injection rate. The main variables were pore structure, mobility ratio, and wettability. The potential for improved oil recovery from rate-sensitive carbonate reservoirs by increased injection pressure, increased injectivity, decreased well spacing or reduction of interfacial tension was evaluated.

Download or read book Unconventional Reservoir Geomechanics written by Mark D. Zoback and published by Cambridge University Press. This book was released on 2019-05-16 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the key geologic, geomechanical and engineering principles that govern the development of unconventional oil and gas reservoirs. Covering hydrocarbon-bearing formations, horizontal drilling, reservoir seismology and environmental impacts, this is an invaluable resource for geologists, geophysicists and reservoir engineers.

Download or read book Wettability Alteration by Glycine and Seawater Injection in Carbonate Reservoirs written by Ricardo Antonio Lara Orozco and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbonate reservoirs contain more than half of the world’s conventional oil reserves. However, since most carbonates are naturally fractured and oil- to mixed-wet there is often significant oil saturation remaining after waterflooding. This is because the injected water mostly flows through the fractures without imbibing into the oil-wet matrix. There is an increasing interest in finding low-cost and enviromentally-friendly wettability modifiers that promote water imbibition by shiftting the wetting state of the rock matrix. These injected chemicals, however, must be able to withstand the high temperatures and high salinity brines typically found in carbonate reservoirs. This study presents experimental investigation and modeling work of the application of glycine as a wettability modifier for carbonate reservoirs to improve oil recovery. We first investigated the potential of glycine in altering the wettability of carbonate surfaces. The experiment consisted of monitoring the contact angle of oil droplets placed on top of natural calcite pieces at 95°C for 5 days. The calcite surface remained oil-wet when submerged in formation brine with an average contact angle of 130°. Similar results were obtained with seawater (SW) with a contact angle of 128°. Low salinity water (LSW) was also tested by diluting SW ten times. It resulted in an average contact angle of 108°. In contrast, a strongly water-wet condition was obtained using FB with a glycine concentration of 5 wt% with an average contact angle of 50°. The oil droplets started to detach from the surface on the fourth day. This was direct evidence of the effect of glycine on altering the wetting-state of carbonate surfaces. We then investigated the enhance oil recovery in carbonate rocks by glycine. Spontaneous imbibition experiments were performed at 95 °C with Indiana Limestone cores. Glycine solutions were prepared with FB, SW, and LSW, with a concentration of 5 wt% and compared to LSW. On average, the glycine solutions recovered about 25% more oil than LSW. The recovery factor as a function of the squared root of time showed a linear trend typical of capillary-dominated flow. Glycine significantly enhanced oil recovery in high temperature and high salinity conditions by promoting spontaneous imbibition of water. An explanation to the previous experimental results is that glycine anion interacts with the positively charged surface of carbonate rocks. Wettability alteration then occurs by glycine adsorption and the corresponding removal of organic material from the rock surface. Based on this hypothesis, this research proposes a surface complexation reaction between glycine and carboxylic acids to model wettability alteration. The equilibrium constant was obtained by matching the zeta potential measurements of synthetic calcite in glycine solutions. The tuned surface complexation model (SCM) was used to investigate the desorption of carboxylic acids as a function of glycine concentration and temperature. The results correlated with the contact angle measurements and the recovery factor from the spontaneous imbibition experiments. High temperature was found to be critical for wettability alteration because it increases the concentration of glycine anion in the aqueous phase. Finally, we coupled the SCM in PHREEQC with a numerical model of two-phase flow displacement to investigate the major geochemical reactions driving wettability alteration in carbonates. We found that eight surface complexation reactions in the SCM can be simplified into a couple of anion exchange reactions between the injected wettability modifiers, glycine anion, sulfate ion, and the adsorbed carboxylic acids. Analytical solutions are then presented for the coupled two-phase and multicomponent reactive-transport model with anion exchange reactions to model the injection of wettability modifiers in carbonates

Download or read book Pore Scale Mechanisms of Carbonated Water Injection in Oil Reservoirs written by Masoud Riazi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns over the environmental impact of carbon dioxide (CO2) have led to a resurgence of interest in CO2 injection (CO2I) in oil reservoirs, which can enhance oil recovery from these reservoirs and store large quantities of CO2 for a long period of time. Oil displacement and recovery by CO2I has been studied and applied in the field extensively. However, CO2I lacks acceptable sweep efficiency, due to the large viscosity contrast between CO2 and resident reservoir fluids. Various CO2I strategies e.g. alternating (WAG) or simultaneous injection of CO2 and water have been suggested to alleviate this problem. An effective alternative strategy is carbonated (CO2-enriched) water injection. In carbonated water, CO2 exists as a dissolved as opposed to a free phase, hence eliminating the problems of gravity segregation and poor sweep efficiency. In this thesis, the results of an integrated experimental and theoretical investigation of the process of carbonated water injection (CWI) as an injection strategy for enhanced oil recovery (EOR) with the added value of CO2 storage are described. High-pressure micromodel technology was used to physically simulate the process of CWI and visually investigate its EOR potential, at typical reservoir conditions. Using the results of these flow visualisation experiments, the underlying physical processes and the pore-scale mechanisms of fluid-fluid and fluid-solid interactions during CWI were demonstrated to be oil swelling, coalescence of the isolated oil ganglia, wettability alteration, oil viscosity reduction and flow diversion due to flow restriction in some of the pores as a result of oil swelling and the resultant fluid redistribution. A mathematical model was developed that accounts for the pore-scale mechanisms observed during the micromodel experiments. In this study, some of the micromodel experimental observations were interpreted and the impact of some of the pertinent parameters on CWI and CO2I processes was studied. The results predicted by the model were linked to the results obtained using a new relationship developed based on the dimensional analysis technique. To examine and investigate the effect of CWI on wettability, micromodel experiments, designed only to observe possible variation of contact angles and spontaneous imbibition displacement mechanisms due to CW, were performed. Contact angle measurements were also conducted to quantify different tendencies of CW and water to wet solid surfaces, using three different solid plates with different salinity of the aqueous phase, under different pressure and temperature conditions. Two other important parameters affecting the performance of CWI, i.e. CO2 solubility in water and its CO2 diffusion coefficient, were also experimentally studied and estimated. A mathematical model was developed to estimate CO2 diffusion coefficient from the corresponding experimental results. The results of this research show that CWI is an effective and efficient injection strategy that offers great potential for enhanced oil recovery and at the same time a unique solution to the problem of reducing CO2 emission.

Download or read book Physical Properties of Rocks written by Jürgen Schön and published by Elsevier. This book was released on 2011-08-02 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: A symbiosis of a brief description of physical fundamentals of the rock properties (based on typical experimental results and relevant theories and models) with a guide for practical use of different theoretical concepts.

Download or read book Waterflooding written by G. Paul Willhite and published by . This book was released on 1986 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Waterflooding begins with understanding the basic principles of immiscible displacement, then presents a systematic procedure for designing a waterflood.

Download or read book Fossil Energy Update written by and published by . This book was released on 1986 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: