Subscriber access provided by The Library | University of Bath
Article
The role of carbon nanotubes in improving thermal stability of polymeric fluids; experimental and modeling Mohamad Amin Halali, Cyrus Ghotbi, Kourosh Tahmasbi, and Mohammad Hossein Ghazanfari Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.6b00784 • Publication Date (Web): 15 Jun 2016 Downloaded from http://pubs.acs.org on June 19, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Industrial & Engineering Chemistry Research is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 54
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Industrial & Engineering Chemistry Research
The role of carbon nanotubes in improving thermal stability of polymeric fluids; experimental and modeling Mohamad Amin Halali 1, Cyrus Ghotbi 1*, Kourosh Tahmasbi 2, Mohammad Hossein Ghazanfari 1 1
Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran
2
Pars Drilling Fluids Company, Tehran, Iran
Abstract At harsh conditions of high pressure high temperature (HPHT) polymers undergo thermal degradation leading to serious loss in fluid rheological and filtration properties. Nanoparticles are the most promising additives proposed to address this challenge. The stability of nanofluids is perused from various facet including rheological and filtration properties, shale stability and zeta potential. The presence of nanoparticles could amazingly reduce the filtration at high temperatures even by 95% and it also had conspicuous effect on shale stability, thermal conductivity and zeta potential. Experimental data were fit to rheological models to determine the best models describing the behavior of the nanosystem. It was clarified that the Sisko and Mizhari-Berk models enjoy the highest accuracy among the others. Moreover, a correlation is developed relating the viscosity of nanofluid to shear rate, temperature and nanoparticles concentration. The model exposed high accuracy regarding high value of average correlation factor which was 0.994. Keywords: Carbon nanotube, Polymers, Surfactant, Rheology, Fluid loss, HPHT
*
Corresponding author: Email Address:
[email protected] (Cyrus Ghotbi)
1 ACS Paragon Plus Environment
Industrial & Engineering Chemistry Research
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
1. Introduction Petroleum industry involves complex operations and processes which may encounter problematic cases. The efficiency and success of such operations pivot on selecting eligible materials and additives. Take for instance drilling operation, a drilling fluid should enjoy numerous properties such as cleaning the cuttings from the hole, moving the cutting to the surface, balancing the formation pressure, helping the wall stability, cooling the drill bit and lubricating the bottom hole assembly (BHA).1 Nowadays, polymers play a vital role in petroleum industry along with drilling industry. Polymers are specifically added to drilling fluid to maintain rheological properties. Increasing the viscosity of fluid, boosting the cutting carrying capacity, a better hole cleaning, providing a suitable filter cake, controlling filtration and preventing shale swelling are the most well-known applications of polymers.2 Unfortunately, at harsh conditions such as high pressure high temperature (HPHT), polymers and more specifically biopolymers experience serious degradation and fail to retain their properties. Subsequently, due failure of the fluid to perform appropriately the well faces severe challenges such as cessation of the drilling operation, lost circulation, barite sag, etc. which all ensue a considerable cost.3 Hence, we can either use oil base fluids (OBFs) rather than water based fluids (WBFs) or using clays as a weighing and thickening agent rather than polymers. First solution neither is cost effective nor environment friendly and its application is only restricted to very sensitive and problematic formations. About the second one, although clays are thermally resistant to higher ranges of temperature, a great amount of clays is required to keep the high dense weighing agents in suspension. Subsequently, the fluid contains high solid content and suffers from exceedingly high viscosity. Keeping the cutting carrying capacity maintained seems to be unavoidable problem in this case. As a result, Drilling fluids need a novel additive to overcome polymers instability and ineffectiveness problem at harsh conditions. To satisfy this need, Nanoparticles are the desired additives proposed in deeper HPHT conditions. Recently, nanoparticles found widespread position through various industries and their exclusive feature have deployed or being developed to endow numerous advantages to industries embracing medicine, aerospace, computer, chemical and petroleum; a fact corroborated by the current surge of publications in literature.4-7 Nanomaterial can unravel different challenges in aforementioned industries with respect to wide range of flexibility in their resistance, strength and performance. In 2 ACS Paragon Plus Environment
Page 2 of 54
Page 3 of 54
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Industrial & Engineering Chemistry Research
extension of their broad application, nanoparticles are fame as a multi-functional additive in petroleum as well as drilling operations. As a matter of fact, they can provide us numerous functions to be applied in drilling fluid. The most outstanding ones are; establish a thin nonerodible impermeable layer of nanoparticle membrane around the wall which prevents spurt loss, fluid loss and limits clay swelling, have a more favorite rheological properties and a higher gel strength, generate lower torque and drag, perform as a lubricity booster and cause fewer abrasion since they are fine enough to have little kinetic energy effect.8, 9 Last but not least, nanoparticles increase the thermal conductivity of the fluid. Needless to say, the more thermally conductive the fluid, the more efficient the cooling of the drilling assembly, the more the operating life cycle of down hole equipment.10 Physically, nanoparticles are particles of size 1nm to 100nm. They are generally made of metal, metal oxide or carbon and in different shapes and forms (crystalline form or super-miscellar). Nanoparticles have considerably higher surface area to volume ratio compared to macro and micro scales which leads to a great change in their physical and chemical properties. Regarding this unique virtue of nanoparticles, they can transport significant values of momentum, mass and energy.7 As the particles become smaller, surface reactivity increases since more surface area is available for particles to interact with each other and with the surrounding medium, i.e. the surface, van der Waals, molecular and atomic forces become dominant rather than body and physical forces. As a result, the interactions as well as bonds become more intense and heat resistant. However, these characteristics are dependent of type, size and shape of the nanoparticles.11 It should be mentioned that nanoparticles are expected to have a game changing feature toward the fluid at very low concentrations (
