Sharif Digital Repository

The hybrid-polymer nanocomposite poly(styrene-methyl methacrylate- acrylic acid) /nanoclay was synthesized by miniemulsion polymerization for novel use as a drilling fluid additive. Three low-solid-drilling fluids (bentonite-based; natural polymer-based; nanoclay-based) were formulated using the hybrid nanocomposite as an additive and their rheological performance compared. The polymer/clay hybrid nanoparticles significantly improve rheological and filtration properties of the drilling fluids and they remain stable at high pressure, high temperature and harsh salinity conditions. The fluids’ filtration properties improve as the concentration of the polymer/nanoclay-hybrid-nanoparticles... 

Sustainable technologies are the main concerns of the 21st century modified oilfield industries. The insufficiency of conventional drilling fluid formulations with a combination of hardly degradable hazardous chemicals as additives raise the demands of field-applicable innovative and environmentally friendly methods. Pistachio Shell discards as degradable wastes, which can intellectually apply in drilling fluid formulation. The experimental oilfield investigations of utilizing pistachio shell powder prove the significant enhancement of rheological properties, reduction of fluid loss and mud cake thickness in both API (Low Pressure —Low Temperature) and High Pressure—High Temperature (HPHT)... 

Deep wells suffer from the instability and disintegration of natural polymers and other commonly used additives under high pressure and high temperature condition. As a result, serious problems such as hydraulic loss, stuck pipe, and high torque and drag are expected to take place which leads to a dramatic increase in cost and time. This study presents the functionality of a novel synthetic based acrylamide-styrene copolymer (SBASC) as a supersede additive for water-based drilling mud. First, the SBASC was synthesized using an emulsion polymerization process and its particle morphological and polymer chain structural properties were determined by Field Emission Scanning Electron Microscopy... 

One of the most prevalent problems in drilling industry is lost circulation which causes intense increase in drilling expenditure as well as operational obstacles such as well instability and blowout. The aim of this research is to develop smart systems for estimating amount of lost circulation making able to use appropriate prevention and remediation methods. To obtain this aim, a large data set were collected from 61 recently drilled wells in Marun oil field in Iran to be used for developing relevant models. After that, using the extracted data set consisting of 1900 data subset, intelligent prediction models including decision tree (DT), adaptive neuro-fuzzy inference systems (ANFIS),... 

Application of the fiber contained fluids has been extensively increased in many industries. In the petroleum industry, fibrous fluids are utilized for different applications. For instance, they have been applied in drilling operations for hole cleaning and cutting removal. In this article, the results of the studies performed on the application of Hydrated Basil Seeds (HBS) as the herbal eco-friendly fiber on hole cleaning and filtration control were presented. In order to investigate the application of HBS on hole cleaning, Polyacrylamide (PA) was added to the pure water to provide the base fluid and HBS at different concentrations were suspended in the base fluid and the effect of HBS on... 

In this study, effects of dried saffron purple petals (SPP) powder were examined on the rheological, fluid loss, and corrosion inhibition properties of bentonite-based drilling fluids. Drilling fluids containing different amounts of the SPP powder were prepared and their rheological behavior was investigated via the rotary viscometry and rheometric mechanical spectroscopy (RMS). Rotary viscometer results were fitted with Power-law, Bingham plastic, and Herschel-Bulkley models and the obtained data were compared with that of the base mud. All models fitted the rotary viscometer data with the determination coefficients higher than 0.93. The presence of 3 wt% of the SSP in the fluid... 

Due to the weak performance of commercially affordable natural and synthetic polymeric thickeners in high temperatures and salinity, they fail to use in many applications especially in saline conditions with high temperatures. In this work, a new salt and temperature resistance acrylamide/styrene/maleic anhydride terpolymer (PASM-t) with self-associative properties was synthesized via a one-step inverse emulsion polymerization and its applicability as a rheological modifier and thickener was investigated. The characteristics of synthesized PASM-t (s-PASM-t) and its aqueous solutions were investigated using FT-IR, FE-SEM, GPC and rheometric mechanical spectrometry (RMS) analyses. The... 

In drilling oil wells a system of complex fluids and chemical additives is used. Losses of these fluids in the well during drilling or disposal of them in well site could transfer pollutants to groundwater. In the present study a number of well sites, located in South of Iran, were studied to indicate types and magnitude of various pollutant materials that remain in the environment undestroyed and have considerable impacts on the underground water resources. Hydrocarbons used in Oil Base Muds (OBM) that can't be biodegrade readily in nature found to be the most severe pollutant material caused by disposal of Drilling Mud and Cuttings. Volume of drilling waste for these oil wells evaluated to... 

Although Multi-Walled Carbon NanoTubes (MWCNTs) are found to influence the rheological behavior of drilling fluids, there are yet some controversies regarding their performance towards reducing formation damage induced by the invasion of water-based drilling fluids (WBFs). To address this important question, we synthesized novel nanocomposite materials via modifying the MWCNT via varying the proportion of carboxylated MWCNTs to PolyVinyl Alcohol (PVA). These nanocomposites were then used to make nano-based drilling-fluids (NDFs). The performance of the NDFs was evaluated by a set of rheological behavior tests, filtration experiments, and core-scale mud flow tests. To distinguish between the... 

Recently, a renewed interest arises in the application of nanotechnology for the upstream petroleum industry. In particular, adding nanoparticles to fluids may drastically benefit enhanced oil recovery (EOR) and improve well drilling, by changing the properties of the fluid, rocks wettability alteration, advanced drag reduction, strengthening the sand consolidation, reducing the interfacial tension and increasing the mobility of the capillary trapped oil. In this study, we focus on roles of clay nano-particles on polymer viscosity. Polymer-flooding schemes for recovering residual oil have been in general less than satisfactory due to loss of chemical components by adsorption on reservoir... 

Despite the fact that hydrophobic nanosilica can improve the stability of water/oil emulsion, there exist controversies pertaining to its influence on oil-based drilling fluid rheological behavior and the subsequent formation damage. The present study addresses the above using a surface modified nanosilica, where the particles were functionalized with different silane-based groups to alter their hydrophilicity: 3-glycidoxypropyl-triethoxy silane (GPTS) and combined GPTS and propyl silane (PGPTS). The NPs were characterized through FTIR analysis, particle size, and zeta-potential measurements followed by flow behavior experiments, core-scale mud flow tests, Computed Tomography (CT) scanning... 

Appropriate execution of drilling operation, in particular for high pressure and high temperature wells, requires accurate knowledge of behavior of the drilling fluid density as a function of pressure and temperature. In this communication, a novel mathematicalbased approach is presented to develop a reliable model for predict the density of four drilling fluid including water-based, oil-based, Colloidal Gas Aphron (CGA) and synthetic. To pursue our objective, a predictive model is proposed using a robust soft computing approach namely least square support vector machine (LSSVM) modeling optimized with coupled simulated annealing (CSA) optimization tool. Moreover, leverage approach, in which... 

During the drilling operation in high-permeability, natural and artificial fractured formations, the lost circulation of drilling mud is a common problem. Various methods have been applied to control lost circulation and among these methods, using Lost Circulation Materials (LCM) is the most common method that blocks the fluid loss channels in the formation by creating structures. In this project, the aim is to develop and use natural fiber-reinforced composites as LCM can be an innovative and technical solution. Natural fiber-reinforced composites have excellent properties such as high specific strength, non-abrasive, eco-friendly, and biodegradability. It seems to be possible that... 

In this paper, the impact of three parameters including nanoparticles geometry, particles aggregation and borehole inclination on induced formation damage from water based drilling fluids were investigated by means of experimental studies. Accordingly, we designed a dynamic filtration setup capable to rotate and change well inclination. Nano-based drilling fluids consisting of spherical, cubical and tubular shapes nanoparticles as fluid loss additives were used. Mud cake quality, core permeability impairment and degree of formation damage at various well inclinations were examined. The cluster structure of aggregated particles were determined using fractal theory and applying dynamic light... 

In drilling industry, energy consumption counts from 20 to 40 percent of total costs. Enhanced water-based mud (WBM) drilling fluids with nanoparticles can save energy in drilling processes. An in-house Taylor-Couette flow system (TCS) was developed at Australian University (AU) to study WBM enhanced by Al2O3, SiO2, and TiO2 nanoparticles. The TCS is really a practical tool to help well drillers with a rough idea of viscosity when nanoparticles are added. The TCS for sure cannot substitute advanced rheometry. The goal of the present experiment is to produce a rough estimate in field operation. Experimental results were examined with several rheology models in our previous publications. In... 

The coupling of rock and thermal stresses along with fluid pressure are particularly important in fractured rock masses, since stress-induced changes in permeability can be large and irreversible under perturbations resulting from various natural and induced activities. A new method is presented to model fracture permeability changes during drilling in fractured rocks. The approach includes finite element method (FEM) for fully coupled thermo-poroelastic analysis of stress distribution around borehole and displacement discontinuity method (DDM) to model fracture deformation. Three cases of overbalanced, underbalanced, and balanced drilling fluid pressure conditions are employed. The... 

The proper understanding of rheological characteristics of CGA based fluids is of crucial importance in determining the performance of the fluid, in order to maintain the most effective fluid properties for safe, efficient, and economical drilling operation. This paper presents a concise investigation on the effect of concentration of the three main components of a novel environmentally friendly lightweight CGA based drilling fluid, i.e., xanthan gum biopolymer, starch, and biosurfactant, to the Herschel-Bulkley rheological model parameters. The three parameters of Herschel-Bulkley model, i.e., yield stress, fluid consistency, and fluid flow index were calculated by fitting the experimental... 

High molecular weight polyacrylamide (PAM) nanoparticle dispersions are products with wide application possibilities, the most important of which is in petroleum industry such as drilling fluid and flooding agent in enhanced oil recovery. For that aim, it is necessary to achieve complete control of the final dispersion and polymer properties during the synthesis step. In this work, PAMs were synthesized by inverse emulsion polymerization of aqueous acrylamide solution in cyclohexane in the presence of emulsifier mixture of Span 20 and Span 80. We present a comprehensive study of the effects of variation of all important reaction conditions (agitation rate, reaction time and temperature,... 

Application of the colloidal gas aphrons (CGAs) in minimizing formation damage by plugging pore mechanism is now wildly accepted due to numerous successful field experience. One of the pivotal factors which affects the pore blockage ability of micro-bubbles is their stability. This experimental study tries to investigate the possible synergistic effect of nanoparticles on improving the stability and other properties of non-aqueous CGA drilling fluids, in both bulk and porous media. In particular, two types of hydrophobic nanoparticles including silicon dioxide nanopowder coated with 2 wt% Silane and nanoclay, in presence of a treated version of bentonite (Bentone 34) as a stabilizer and... 

To improve the thermal stability of starch in water-based drilling fluid, monoethanolamine (MEA) was added, and the effect was investigated by laboratory experiment. The experimental results show that the addition of monoethanolamine (MEA) increases the apparent viscosity, plastic viscosity, dynamic shear force, and static shear force of the drilling fluid, and reduces the filtration rate of drilling fluid and thickness of mud cake apparently. By creating hydrogen bonds with starch polymer, the monoethanolamine can prevent hydrolysis of starch at high temperature. Starch, as a natural polymer, is able to improve the rheological properties and reduce filtration of drilling fluid, but it works...