Unconventional Oil Exploitation Research Articles

Experimental study on functional characteristics of pH-sensitive nanoparticles for pressure reduction and augmented injection in tight oil reservoir

In this paper, a novel kind of pH-sensitive nanoparticles (NPs) was synthesized for pressure reduction and augmented injection in the exploitation of the tight oil reservoir. The physical properties of the pH-sensitive NPs, including dispersibility, hydrodynamic diameter of the NPs, zeta potential, anti-swelling ability, interfacial tension, wettability, and pressure-decreasing capacity, were investigated as functions of the pH value of the water solution. The results indicate that with the increase of the pH value of pure water, the hydrodynamic diameter of the NPs decreased from hundreds to tens of nanometers, and the absolute value of the zeta potential increased from 3 mV (pH = 7) to about 56 mV (pH = 12). When the pH value changed from weakly alkaline to neutral, the anti-swelling rate increased. When the pH value increased to around 12, the anti-swelling rate reached 42%, and the interfacial tension decreased from 9.5 mN/m to around 4.0 mN/m. The wettability of the NPs was also influenced by the pH value; as the pH value increased, the wettability changed from hydrophobic to hydrophilic. Additionally, core-flooding experiment showed that the wettability of the NPs was altered from hydrophilicity to super hydrophobicity when the pH gradually decreased from 10 to 7, and the injection pressure in the tight sandstone outcrop core was reduced by 22.77%. This study is expected to inspire new strategies for the synthesis of nano-SiO2 materials, which are particularly used for depression and augmented injection in unconventional oil exploitation.

Reversible adhesion surface coating proppant

Proppant is a key material in the hydraulic fracturing process, which has been widely used in unconventional oil exploitation. Normal proppants are easy to sedimentate and accumulate at the entrance of shale fracture, which will block the diversion of water, oil and gas. Coated proppants (CPs) are fabricated by coating resin on normal ceramic proppants through a simple method, which is dramatically enhanced the supporting properties in shale fracture and easy to scale up. Compared with uncoated ceramic proppants, the self-suspension ability of CPs is ∼11 times higher, which are able to migrate and distribute farther and deeper inside the fracture. At the same time, Coating enhanced the 23.7% of adhesive force in maximum, which makes the CPs easier to adhere on the fracture surface to supportthe shale fracture. Besides, the liquid conductivity of CPs is 60% higher than uncoated ceramic proppants at 13.6 MPa pressure. This method is expected to fabricated varieties of proppantsfor shale fracture supporting to improve the exploration of unconventional oil and gas resources.

Thermal upgrading of Athabasca bitumen in porous media: Limitations and kinetic modelling

Technologies merging enhanced oil recovery with in situ upgrading can significantly increase the economic and environmental efficiency of unconventional oil exploitation. This work targets understanding the effects of thermal processing in a porous medium at moderate temperatures (340–370°C) and residence time between 12 and 48h for Athabasca bitumen. The main limitation for upgrading via thermal cracking in the reservoir is the formation of coke precursors. Vacuum residue (VR) conversions above 32% fail to produce a stable product. Below 32% VR conversion transporting oil properties are just slightly improved. Product viscosity is reduced by 1–2 orders of magnitude, while moderate improvement in other properties are achieved such as 3 points increase in API gravity when stable product is the limit and 7–23% reduction in sulfur content. Additionally, coke precursors are significantly retained by the sand matrix, as analyzed by Microcarbon residue testing of the sand. This retention may in time cause damage to the porous media, thus limiting the applicability of thermal cracking as an in situ upgrading process. The presence of the porous media increases the apparent reaction order for the Vacuum Residue conversion to a second order reaction. A five lump kinetic model with seven reactions was successfully used to predict the product distribution with an overall error of 7% and excellent correlation to Arrhenius law. Obtained activation energies are in the range of 100–250kJ/mol.

The forgotten implications of low oil prices on biofuels

AbstractThe sudden drop of oil prices since mid‐2014 has echoed in the news due to implications at national and international levels. For unknown reasons, the effects of quasi permanent low oil prices on biofuels were ignored. With current oil prices, biofuels are not competitive with gasoline, thus the blend wall of regular cars will not rise as soon as expected, and the ethanol's market saturation and the high prices of capital and operational costs are factors that do not contribute to boost consumption. Objections to biofuels subsidies, as well as arguments against the rise of food prices as a consequence of biofuel production from feed crops instead of agricultural and forestry wastes, will become more valid than ever. However, to fulfil biofuel policies regarding energy independence and decarbonization, and in the face of the failure of important advanced biofuel projects, huge public expenditures (incentives/subsidies), extended biofuel mandates, improvement in biofuel technologies, and security for investments through coherent and stable policies are needed. Furthermore, it is advisable to maintain a sustainable conventional biofuel industry to facilitate the transition to advanced biofuels. Citizens must be aware of the indirect costs of fossil fuels (coal mining, pollution, and energy security) and realize that the deployment of biofuels is both a question of opportunity and a challenge. The devastating effect of low oil prices on biofuels and on unconventional oil's exploitation and the constraints to biofuel developments, are still in the horizon, especially when OPEC will no longer act as the swing oil producer. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

The Importance Of Energy Solutions For A Safe And Rational Development

AbstractA new industrial revolution is on the verge in the energy domain considering the knowledge and skills acquired through the development of new energy technologies. Shale gas processing, unconventional oil exploitation, new exploring/drilling methods, mature renewable energy or in progress, all generated a wealth of knowledge in new technology. Therefore, this paper aims to analyse the positive and negative aspects of energy solutions, and to reveal the way to a world where a valid sustainable development, based on safe and rational premises, is actually considered. The paper also introduces suggestions for the energy system, which has a crucial importance in coping with the resource management of the future, where the economic, social, and environmental/climate needs of the post-crisis world should be suitably considered.

Technology Focus: Unconventional Resources (July 2009)

Technology Focus The baton has been passed, and so, during the next 3 years, I will provide here a brief editorial about and drawing your attention to recent publications or events pertaining to unconventional resources. I have been around the industry since the late 1970s and have seen many changes since. I started my petroleum career working in the unconventional oil sands of Alberta, Canada, which are similar to but colder than those of Venezuela. Although unconventional-oil exploitation is still a dynamic topic, activity in unconventional gas (e.g., tight gas, shale gas, and coalbed methane) is picking up as environmental awareness surrounding the exploitation of unconventional resources grows. So, my editorial is about "unconventionals," a very trendy word indeed. What are unconventional resources and what characterizes them? I will broach this topic in a general way without offering a definition—this has been debated for a long time! There are unconventional locations (e.g., deep water or beneath national parklands, a lake, or a city), which require unconventional methods. There are unconventional formations (e.g., oil sands and coalbed methane) containing hydrocarbons that cannot be produced in a conventional (primary or secondary) way with available equipment, or are not being exploited because of unavailable methods and/or high costs. Unconventional technologies are being developed to recover these unconventional and difficult-to-recover hydrocarbons, from drilling and completions to logging to production. There are unconventional "energies," with a shift toward renewable ones such as wind, solar, geothermal, and deep ocean energies, and biofuels. Obviously, the environment is a priority, and large efforts are expended nowadays in this direction. For example, greenhouse gases are being captured and disposed of in deep rocks or in the water in pilot projects; these gases are also used for enhanced oil recovery. The more-than-century-old "oil and gas" industry has changed into an "energy" industry. As this industry is redefined, many of the technologies that traditionally have been used for oil and gas exploration and development are needed to expand unconventional resources and advance the development of other sources of energy, whether they are nonrenewable or renewable ones. It is natural for this growth of the industry to happen. Along the way, we will find/discover new technologies that will also help the development or redevelopment of the old established sources. Bright is the future! Unconventional Resources additional reading available at OnePetro: www.onepetro.org SPE 119891 • "Workflow for Stratigraphic Characterization of Unconventional Gas Shales" by Roger M. Slatt, SPE, University of Oklahoma, et al. IPTC 12743 • "Importance of Unconventional Oil Resources in Shaping the Far East Energy Future" by Philip Stark, IHS, et al. SPE 113852 • "Oil and Gas Expertise for Geothermal Exploitation: The Need for Technology Transfer" by Gioia Falcone, SPE, Texas A&M University, et al.