Welch, John Charles (Baker Hughes Inc.) | Newman, Caleb Ray (U. of Houston) | Gerrard, David Peter (Baker Hughes Inc.) | Mazyar, Oleg A. (Baker Hughes Inc.) | Mathur, Vipul (Baker Hughes Inc.) | Thieu, Vu (Baker Hughes Inc.)
The oil and gas industry is continuously looking for robust material and tool designs that provide greater operational flexibility in aggressive environments. Coating systems, engineered at the nanometer scale, exhibit enhancements that can address these needs.
Our study of nano-engineered coatings started with simple polymer-polymer self-assembled systems, to which was added nano-sized clay or one of several carbon-based nano materials. We evaluated application of different cross linker treatments. To evaluate the variables involved in preparation of the coating systems we quantified thickness and contact angle, and we performed micrographic and scanning electron microscope analysis of standard coated substrates. When applied to copper coupons we determined a 91% reduction of corrosion after four hours, 60% after 24 hours, and 13% after ninety hours in a hydrogen sulfide gas blend. Nano-engineered coatings applied to common oilfield elastomeric materials produce a 40x delay in swelling and decrease in transmission of carbon dioxide gas by 73%. All of the above are lab results, and the comparisons were made to baseline commercially available rubber compounds without nano-enhancement.
Our results demonstrated that nanotechnology can be very effectively used to significantly modify properties of commonly used oilfield materials. Reduced corrosion can extend the life of downhole electronics and motors. The oil swelling rate can be drastically reduced to give operators a greater flexibility in setting the packers and reducing intervention. These findings can be used to design new packers, sealing elements and other elastomeric components used in downhole environment. This paper will present our recent lab results along with a postulated mechanism on how nanotechnologies can impact material performance in downhole applications.
Thin films, typically less than 1µm thick, are created by alternately exposing a substrate to positively-charged and negatively-charged molecules or particles, as shown in Fig. 1. In this case, steps 1-4 are continuously repeated until the desired number of ?bilayers? (or cationic-anionic pairs) is achieved. However, an additional cation or anion can be introduced in the setup, leading to formation of ?quadlayers? (or cationic-anionic-cationic-anionic layers). Each individual layer may be 1-100+ nm thick depending on chemical properties, molecular weight, charge density, temperature, deposition time, counterion, and pH of species being deposited. The ability to control coating thickness down to the nanometer level, to easily insert variable thin layers without altering the process, to economically use raw materials (due to their thin nature), to self-heal and process under ambient conditions are some of the key advantages of this deposition technique. These films often have properties that are better than comparable thick films (greater than 1µm).
2.1 Layer-by-Layer Coating System
The coatings of interest contained a combination(s) of polymers like branched polyethyleneimine (B-PEI) and poly(acrylic acid) (PAA) along with nanomaterials - carbon-based and/or clay to produce 'nano brick wall' films that are fully dense and transparent. Glutaraldehyde (GA) or exposure to UV light was also used in polymer-based bilayer system to crosslink. Peroxide-based crosslinking systems were also briefly investigated.
The potential to confidently apply water-based drilling fluids in unconventional shale formations has been studied using engineered nanoparticles to minimize shale permeability through physically plugging the nanometer-sized pores. This paper discusses the development of nanoparticle technology and testing protocols developed using Marcellus and Mancos as shale candidates. In addition, new methods to better understand the plugging mechanism are currently under evaluation.
Nanoparticles in this study are specifically designed to physically plug the nanometer-sized shale pores, thereby reducing pressure transmission in the shale. Silica nanoparticles are commericially available and can be engineered to meet all specifications needed for the purpose. The particle size can vary between 5 and 100 nanometers (nm) and. The right sizes of nanoaprticles can be selected and in combination with a correct fluid loss package can minimize the fluid rock interaction. Surface treatment on the nanosilcia particle has been discovered to have a major influence on the final performance. It was revealed that appropariately sized nanoparticles with surface treatments compatible with ions present in drilling and formation fluids is required for effective plugging.
Marcellus and Mancos shales were used in the development phase due to their wide industry interest and geological similarity. The authors examined an in-house method, still under development, using the Shale Membrane Test that is intended to provide quantitative plugging and filter cake measurements using various shale samples.
Nanotechnology has already contributed significantly to advances in several industries, e.g. electronics, biomedical, aerospace, and more recently the energy industries. In particular, nanotechnology has the potential to pioneer changes in several areas of the oil and gas industry, such as exploration, drilling, production, enhanced-oil-recovery (EOR), and refining. For example, superparamagnetic nanoparticles that could act as contrast agents could be used to accurately determine the oil saturation distribution in a reservoir and help determine bypassed oils. Moreover, by correctly functionalizing the surface of the magnetic nanoparticles, colloidal suspensions of these nanoparticles that are stable at high temperatures and high salinities (oil-well conditions) can be prepared and could be co-injected with sweep and/or fracture fluids and their location determined and tracked over time by electromagnetic measurements. With this in mind, a study of the magnetic properties of ferrite nanoparticles with varying compositions (MFe2O4; M = Fe, Al) has been conducted to determine the magnetic responses of the various particles in order to evaluate the likelihood of using them as magnetic contrast agents in the oil and gas industry.
New technologies are emerging oil industry to afford the need for increasing oil recovery from oilfields, one of which is Nanotechnology. This paper experimentally investigates a special type of Nanoparticles named Polysilicon ones which are very promising materials to be used in near future for enhanced oil recovery. There are three types of Polysilicon Nanoparticles which can be used according the reservoir wettability conditions. In this paper, hydrophobic and lipophilic polysilicon (HLP) and naturally wet polysilicon (NWP) are investigated as EOR agents in water-wet sandstone rocks. These two Nanoparticles recover additional oil through major mechanisms of interfacial tension reduction and wettability alteration. The impact of these two Nanoparticle types on water-oil interfacial tension and the contact angle developed between oil and the rock surface in presence of water phase were investigated. Then, several coreflood experiments were conducted to study their impacts directly on recoveries. Furthermore, optimum pore-volume injection of each Nano-fluid was determined according the pressure drop across the core samples.
The results show a change toward less water-wet condition and a drastic decrease in oil-water interfacial tension from 26.3 mN/m to 1.75 mN/m and 2.55 mN/m after application of HLP and NWP Nano-fluids respectively. As a result, oil recoveries increase by 32.2% and 28.57% when a 4 gr/lit concentration of HLP and NWP Nano fluids are injected into the core samples respectively. According the differential pressure data, two and three pore-volume injections of NWP and HLP Nano-fluids are the best injection volumes respectively. Finally, HLP and NWP Nanoparticles improve oil recovery without inducing any formation damage according the oil recovery and pressure drop data.
To meet the rising energy consumption in the world, there is a dire need to produce more crude oil. Stagnant oil production and unimpressive recovery by primary and secondary recovery methods have made the situation more precarious. Hence, attention is being paid to more efficient technology (i.e. Nanotechnology) for recovering more oil from the existing oilfields. On an average, only about a third of the original oil in place can be recovered by the primary and secondary recovery processes (Kong and Ohadi, 2010). The rest of oil is trapped in reservoir pores due to surface and interfacial forces. This trapped oil can be recovered by reducing the capillary forces that prevent oil from flowing within the pores of reservoir rock and into the well bore (Wu et al., 2008). Capillary pressure which is the force necessary to squeeze a hydrocarbon droplet through a pore throat (Bear, 1988) reduces by reduction of oil-water interfacial tension and wettability alteration. Polysilicon Nanoparticles have a great potential for increasing pore scale displacement efficiency through reduction of interfacial tension and wettability alteration. There exist three types of polysilicon Nanoparticles, which can be used in proportion to reservoir wettability (Ju, 2002). In last decade, some studies have been done for application of polysilicon Nanoparticles in water-wet sandstone (Onyekonwu, 2010; Ju, 2009; Ju, 2002; Ju, 2006; Wang, 2010). In previous investigations, wettability alteration discussed as the main mechanism for increasing recovery efficiency. However, from the view of the literature in this field, there exist lack of fundamental understanding about the mechanism of oil recovery by utilizing neutrally-wet polysilicon (NWP) and hydrophobic Lipophilic polysilicon (HLP) Nanoparticles in enhancing oil recovery(Onyekonwu, 2010). This paper presents a comparison between recovery efficiency of these Nanoparticles in enhancing oil recovery from one of the Iranian oil reservoirs and discuss about main mechanisms contributed in oil recovery.
Parvazdavani, Mohammad (sharif U of Technology) | Masihi, Mohsen (Sharif University of Technology) | Ghazanfari, Mohammad Hossein (Sharif University of Technology) | Sherafati, Marjan (Sharif University of Technology) | Mashayekhi, Leila (Sharif University of Technology)
It has been shown that one kind of poly silicon particles with sizes ranging from 10-500 nm, can be used in oilfields to enhance the oil recovery of water injection by 15-20%. The contributing mechanism might be reducing the interfacial tension which appears through improving relative permeability of the oil-phase. However, fundamental understanding of how hysteretic behavior of relative permeability curves affected by nanosilica particles remains a topic of debate in the literature. In this study, water as well as water dispersed nanosilica particles floods was performed on sandstone rock sample saturated by light crude oil supplied from one of Iranian oil reservoir, and the relative permeability curves for both oil and water/ water dispersed nanosilica particles phases were determined for two successive cycles of imbibitions/drainage processes. The results revealed that the hysteresis in relative permeability of both oil and water phases decreased as the dispersed silica nano particles were used in the tests, and the hysteretic behavior of relative permeability curves decreased as the injection proceeds into the 2nd cycle of injection. Moreover, the relative permeability of non-wetting phase changes significantly while the changes for wetting phase is not much considerable. This work illustrates for the first time the role of dispersed silica particles on hysteretic trend of two-phase oil-water relative permeability curves.