微纳米技术在石油和天然气工业中的应用最近取得的进展概述.pdf

spe 138241 applications of micro and nano technologies in the oil and gas industry- an overview of the recent progress xiangling kong, spe, china university of petroleum (beijing), and michael m. ohadi, the petroleum institute (uae) copyright 2010, society of petroleum engineers this paper was prepared for presentation at the abu dhabi international petroleum exhibition illustrations may not be copied. the abstract must contain conspicuous acknowledgment of spe copyright. abstract micro and nano technologies have already contributed significantly to technological advances in a number of industries, including the electronics, biomedical, pharmaceutical, materials and manufacturing, aerospace, photography, and more recently the energy industries. micro and nano technologies have the potential to introduce revolutionary changes in several areas of the oil and gas industry, such as exploration, drilling, production, enhanced oil recovery, refining and distribution. for example, nanosensors might provide more detailed and accurate information about reservoirs; specially fabricated nanoparticles can be used for scale inhibition; structural nanomaterials could enable the development of petroleum industry equipment that is much lighter and more reliable and long-lasting; and nanomembranes could enhance the gas separation and removal of impurities from oil and gas streams. other emerging applications of micro and nano technologies in the petroleum industry are new types of “smart fluids” for enhanced oil recovery (eor) and drilling. in short, there are numerous areas in which nanotechnology can contribute to more efficient, less expensive, and more environmentally sound technologies. this paper provides an overview of the micro and nano technologies with a particular focus on nanotech-based solutions for the oil and gas and the broader energy industry. recent developments in research in areas of significance to the oil and gas industry are briefly reviewed and include two case study examples. the potential opportunities and challenges that face future trends of nanotechnology applications in the oil and gas industry are also discussed. introduction the global demand for energy is anticipated to continue to increase over the next few decades with the expectation that the worlds energy consumption will increase by as much as 50% in the next 20 years. although the use of alternative energy sources, such as nuclear and renewable energy will increase in the coming years, the increase will be relatively small and the main role of the alternative energy sources, at least for the next two decades, will be to complement and supplement, rather than replace, the use of hydrocarbons. accordingly, meeting the worlds growing energy demand will be a major challenge in the coming decades and will only be possible with revolutionary breakthroughs in the oil and gas industrys core science and engineering. breakthroughs in nanotechnology have the potential to move the industry beyond the current alternatives for energy supply by introducing technologies that are more efficient and more environmentally sound. broadly speaking, nanotechnology refers to a field of applied science and technology whose unifying theme is the control of matter on the atomic and moleculer scale, generally 100 nanometers or smaller, and the fabrication of devices with critical dimensions that lie within that size range. specifically, advancements in nanotechnology have led to development of significantly enhanced enabling materials, tools, and devices with features and characteristics that cannot be matched by conventional technologies. research and development in nanotechnology has exploited the unique combinations of mechanical, thermal, electronic, optical, magnetic, and chemical properties observed at the nano-length scale (krishnamoori, 2006). 2 spe 138241 nanotechnology is poised to dramatically impact all sectors of industry (mokhatab et al., 2006). for example, in oil and gas applications, nanotechnology could be used to develop new resources by enhancing thermal conductivity and improving downhole separation (esmaeili, 2009). because the oil and gas industry relies on the strength and stability of its materials, the extreme precision of nanoscale manipulation offers geoscientists and engineers not only miniaturized devices to work with but also drastically improved novel materials. a recently published paper makes the point that nanotechnology may someday boost the average global recovery factor of oil and gas by 10% and due to rapid advances in research in nanotechnology in the oil and gas industry, an explosion in applications of nanotechnology in the industry is expected in the near future (tippee, 2009). nanoscale metals have already been used to delineate ore deposits for geochemical exploration (wang et al., 1997). nanotechnology also opens interesting prospects for improved oil recovery in the form of tailored surfactants. these can be added to the reservoir in a more controlled way than with existing substances, thereby releasing more oil. nanotechnology could also be used to develop new metering techniques with tiny sensors to provide improved information about the reservoir. other emerging applications of nanotechnology in the oil and gas industry are new types of “smart fluids” for improved oil recovery and drilling (evdokimov et al., 2006; zitha, 2005). such “smart fluids” will further enhance drilling by adding benefits such as wettability alteration, advanced drag reduction, and binders for sand consolidation (chaaudhury, 2003; wasan and nikolov, 2003) nano-catalysts may also offer a solution for on-site upgrading of bitumen and heavy crude oil (ying and sun, 1997; scott et al., 2003). this paper first presents the challenges currently faced in the oil and gas industry and the potential solutions the nanotechnology may offer. next, recent developments in nanotechnology in select major areas of interest to the industry and relevant research areas are discussed. to conclude, the challenges and future trends of nanotechnology applications in the oil and gas industry are highlighted. oil and gas industry challenges and naonotechnology solutions the oil and gas and the broader energy industry is facing major future challenges from upstream to midstream to downstream applications in terms of materials, techniques and safe environmental operations. these challenges (summarized in table 1) have forced the industry to look for revolutionary solutions. in recent years micro and nano technologies have received substantial attention as potential candidates to offer solutions to some of these challenges. in the following a brief review of the recent progress in relevant research and development in areas of significance to the oil and gas are reviewed and followed by a summary of possible solutions the nanotechnology can offer in a number of areas of critical importance to the industry. exploration as easily accessible oil resources continue to shrink, demand will continue to increase for more sophisticated methods to improve field characterization techniques and processes that may lead to enhanced oil recovery. industry geoscientists believe that substantially more oil and gas could be extracted if their understanding of the chemical and physical properties of existing reservoirs were improved. even with the use of sophisticated secondary and tertiary enhanced oil recovery techniques, such as water flooding, gas flooding, chemical flooding and thermal flooding, a large amount of oil and gas is ultimately left behind. according to well established estimates by the u.s. department of energy (doe) and other sources, approximately 67 percent of all u.s. oil remains in place and will increasingly require advanced technologies to recover it. in fact, with the exception of seismic techniques, most sensing technologies penetrate and provide information only few inches from the wellbore, thus offer limited information. current state-of-the-art technologies still lack the needed resolution and/or the ability to deeply penetrate reservoir lithologies. moreover, in hostile conditions, such as high temperature and high pressure, conventional electrical sensors and other measuring tools are often not reliable. despite the use of advanced 3-d and 4-d seismic surveys, the industry still needs advanced downhole electrical methods, sensitive electromagnetic imaging methods, and sophisticated modeling and simulation techniques to improve in-depth understanding of the reservoirs. accurately locating and characterizing the remaining oil and gas in these reservoirsbillions of barrels of potentially available supply in many cases, particularly in the oil-rich areas of the worldis a great motivation for the development of novel techniques, realizing even a slight improvement in the enhanced oil recovery factors translates to billions of dollars in additional revenues. new sensor technology is needed to probe properties deep in reservoirs, which would allow us to unravel the complex nature of the rock and fluid interactions and to design suitable exploitation plans for trapped oil and gas. better sensor technology would also allow us to attain improved temperature and pressure ratings in deep wells and hostile environments. new imaging and computational techniques are also needed to allow better discovery, sizing, and characterization of reservoirs. with the tightest passages (or pore throats) in typical oil-bearing sandstones ranging from 1-15 m, injection of custom-designed nanoparticles or nanosensors, ranging from 1-100 nm, has captured the attention and imagination of petroleum geologists (pitkethly, 2004). to explore the potential of this technology in the u.s., in 2008 the advanced energy consortium (aec) was constituted in spe 138241 3 cooperation with major oil companies, such as bp, conocophillips, shell, schlumberger, and total. this consortium, with an annual budget of several billion dollars, was charged with developing nanotechnologies to improve oil and gas production. the primary goal of the research consortium is to develop subsurface micro-and nanosensors that can be injected into oil and gas well bores. by virtue of their ultra-small size, these nanoagents would migrate out of the wellbores and into and through pores of surrounding geological structures to collect data about the physical characteristics of hydrocarbon reservoirs. nanoparticles with noticeable alterations in optical, magnetic, and electrical properties compared to their bulk counterparts, are excellent tools for the development of sensors and the formation of imaging contrast agents (krishnamoori, 2006). hyperpolarized silicon nanoparticles provide a novel tool for measuring and imaging in oil exploration (song and marcus, 2007). nanosensors deployed in the pore space by means of “nanodust” can provide data on reservoir characterization, fluid-flow monitoring, and fluid-type recognition. nano-ct can image tight gas sands, tight shales, and tight carbonates in which the pore structure is below what micro-ct can detect. in addition, nanotechnology has the potential to help develop geothermal resources by enhancing thermal conductivity, and nano-based materials could be used for geothermal production. nanoscale metals have already been used to delineate ore deposits for geochemical exploration. drilling and production as readily accessible reserves become depleted, the oil and gas exploration and production (e xu et al., 2003), have been widely employed to increase compressive and flexural strengths of portland and belite cements. furthermore, the self-monitoring capability of cement mortar with nano-fe2o3 has been reported (li, h. et al, 2004). due to the special properties and interaction potential of nanomaterials compared to their parent materials, the nanomaterials are considered the most promising future materials for “smart fluid” design for oil and gas field applications. moreover, due to the scope of manufacturing of tailored nanoparticles with custom-made functional behaviors, ionic natures, physical shapes and sizes, charge densities and unit volumes, nanotechnology has opened the door to the development of a new generation of fluids defined as “smart fluids” for drilling, production and stimulation-related applications. such smart fluids will further enhance drilling by adding benefits such as wettability alteration, advanced drag reduction, and binders for sand consolidation (chaaudhury, 2003; wasan and nikolov 2003). one specialized petroleum laboratory has developed an advanced fluid mixed with nanosized particles and superfine powder that significantly improves drilling speed. such nanofluids can eliminate damage to the reservoir rock in the well, making it possible to extract more oil (esmaeili, 2009). nickel nano- and micro- 4 spe 138241 particle adsorbents have been employed for removing asphaltanes from heavy oil model solutions by adsorption. the results demonstrate that the asphaltene adsorption capacity onto nickel nanoparticles show undeniable advantages compared to nickel microparticles (nassar et al., 2008). enhanced oil recovery (eor) the fast growth of worldwide demand for oil can be met effectively in only two ways: by finding new hydrocarbon resources or by enhancing the oil recovery of available reservoirs. however, the rate of new oilfield discoveries is declining, and most of the producing oilfields are in the late stages of production. the importance of improving oil production efficiency by enhanced oil recovery (eor) techniques is highly acknowledged because in many of the worlds reservoirs about two thirds of the oil in place cannot be recovered by conventional production methods. three major categories of eor have been found to be commercially successful to varying degrees: (1) thermal recovery, which involves the introduction of heat such as the injection of steam to reduce the viscosity of the heavy viscous oil and to improve its ability to flow through the reservoir; (2) gas injection, which uses gases such as natural gas, nitrogen, or carbon dioxide that expand in a reservoir to push additional oil to a production wellbore, or other gases that dissolve in the oil to lower its viscosity and improve its flow rate; and (3) chemical injection, which can involve the use of long-chained molecules called polymers to increase the effectiveness of waterflood, or the use of detergent-like surfactants to help lower the surface tension that often prevents oil droplets from moving through a reservoir. however, each of these techniques has been hampered either by its relatively high cost or, in some cases, by relatively inefficient oil recovery. for conventional water and gas flooding, the driving fluids often quickly channel through the formation to the producing well, bypassing most of the oil and leaving it uncovered due to the unfavorable mobility ratio of the driving fluids and the driven fluids. chemical eor processes such as polymer flooding, alkaline injection and surfactant flooding or their combinations are also limited by the high cost of the injectants, potential corrosion of the formation, and injectant loss during the flow-through reservoir. once these injectants are entrapped by the pore throats, there is a loss of mobility control, absolute permeability reduction, poor oil recovery, and high materials loss. therefore, low-mobility, cost-effective injectant is greatly needed. nanoparticles offer a way to control oil recovery processes that is unmatched by any current or previous technology. these nanoagents can drastically increase oil recovery by improving the geomechanics of a reservoir through the improvement of surface tension as well as actual modification of the reserves themselves. the viscosity of a fluid injected to displace oil, such as water, co2 or surfactant solution, is often lower than the viscosity of the oil. in this situation, adding nano particles can tune up the viscosity of the injected fluid to an optimum level, with net effect of improving the mobility, thus the oil recovery efficiency. several studies have reported that upon addition of the nanoparticles, the properties of the base fluid such as density, viscosity, thermal conductivity and specific heat can be increased. laboratory tests (shah and rusheet, 2009) show that the viscosity of co2 combined with 1% cuo nanoparticles and a small amount of dispersant is over 140 times greater than conventional co2. therefore, by dispersing such nanoparticles into the driving co2 fluids, a favorable mobility ratio and high sweep efficiency can be obtained, leading to a higher oil recovery. another research project, sponsored by conocophillips at the university of kansas (ku) (“nanotechnology,” 2008), aims at creating a new class of polymer-type nanoparticles that can be incorporated with eor injection fluids to improve hydrocarbon recovery from reservoirs in more efficient and environmentally favorable ways. with their ultra-small size and very high surface area/volume ratios, such nano-polymers can penetrate small pore throats without becoming trapped, and the amount of expensive injection can be decreased. thus, a cost-effective process of eor can be achieved. emulsification is another way to increase viscosity, but many current methods to stabilize emulsions are expensive or poorly suited to large-scale applications. stabilization with surface-modified nanoparticles could overcome these problems. emulsions stabilized by nanoparticles can withstand high temperature reservoir conditions for extended periods, which can expand the range of reservoirs to which eor can be applied (tiantian et al., 2009). emerging nanoemulsions such as water-in-oil (w/o) and oil-in- water (o/w) have also attracted great interest for oil applications (morales et al, 2003; del gaudio et al, 20