Synthesis and performance evaluation of a water-soluble copolymer as high-performance fluid loss additive for water-based drilling fluid at high temperature

Drilling fluids are widely used in the drilling of deep wells to clean and transport the rock cuttings, maintain the sidewall of oil well, lubricate and cool the drilling bit, and control the formation pressures. The present work aims at improving the high-temperature resistance of water-based drilling fluid by using the newly synthesized fluid loss additive named PAASD. This copolymer was obtained through the solution polymerization of four kinds of monomers. The synthesis conditions with the optimal API filtration were studied by single synthetic experiment, and the chemical structure of final product was confirmed by FTIR spectroscopy. The target product was carried out with thermal stability analysis, rheological property, filtrate property, temperature resistant capacity, salt tolerance capacity, micro-crosslink structure property, particle size distribution and the compatibility performance experiment. The results showed that PAASD was an efficient fluid loss additive, and the API filtration of fresh water drilling fluid containing 2% PAASD was only 5.2 mL, it was 10.6 mL after aging at the condition of 200°C and 16 h. Besides, PAASD has a good thermal stability, salt tolerance, and it could improve the rheological property of drilling fluid system obviously. Therefore, it could be used as fluid loss additive of water-based drilling fluid in salty and high-temperature environment.     

盐对粘土／氢氧化铝镁／甘油胶体性能的影响

通过电泳淌度、流变参数和中压滤失量的测定，研究了ＫＣｌ和ＡｌＣｌ３对带永久负电荷的蒙脱土与带永久正电荷的氢氧化铝镁／甘油形成的混合悬浮体胶体性能的影响，并对影响机理进行了深入探讨     

Assessment of two prop-2-enamide-based polyelectrolytes as property enhancers in aqueous bentonite mud

Large amounts of hydrocarbons are located in deeper formations where higher temperatures are experienced, hence designing a proper drilling fluid to tolerate such conditions has represented a challenging task for researchers in the field. The current work is focused on evaluating the effectiveness of poly(prop-2-enamide-sodium 2-acrylamido-2-methyl propane sulphonate-ethenyl ethanoate), designated as CP4 and poly(prop-2-enamide-sodium-prop-2-enoate-N,N′-dimethylprop-2-enamide-N-vinylpyrrolidone), denoted as CP5 as additives in water-based drilling fluids. The effect of temperature and salt on the copolymer-incorporated mud properties was examined. The reaction conditions were optimised for synthesis of the terpolymer and tetrapolymer. The chemical structures of copolymers were characterised by Fourier transform infrared (FTIR) spectroscopy. The thermal stability of the copolymers was assessed by thermogravimetric analysis (TGA). Both copolymers exhibited effectiveness in mud viscosity enhancement. The presence of the rigid pyrrole ring in CP5 and the bulky sulphonate side-group in CP4 provided thermal resistance and salt tolerance in their respective copolymer structures. CP4 demonstrated greater fluid-loss reduction by providing 7-fold American Petroleum Institute (API) fluid control and 8-fold high temperature high pressure (HTHP) fluid-loss control at 150°C while CP5 achieved 6-fold control in both parameters in comparison with the blank.     

Amphipathic anionic surfactant modified hydrophilic polyethylene glycol-nanosilica composite as effective viscosifier and filtration control agent for water-based drilling muds

Highly stabilized and dispersible composites of polyethylene glycol and silica nanoparticle in aqueous drilling mud can provide desirable rheological and filtration properties for drilling jobs. Therefore, high-quality hydrophilic polyethylene glycol-nanosilica composite modified by amphipathic anionic sodium dodecyl sulfate (PEG-SiO₂ NC-SDS) to improve the rheological and filtration properties of water-based muds (WBMs) was submitted. Test of zeta potential, functional groups, morphology, elemental composition, and temperature stability together with rheology and filtration tests were undertaken to assess the wide-ranging mud properties of the SDS modified PEG-SiO₂ NC drilling muds. Zeta potential, FTIR, FESEM, EDX, and TGA results indicate that the SDS modified PEG-SiO₂ NC was effectively formed and modified; it embodies exceptional thermal stability and is efficiently dispersed. The SDS modified PEG-SiO₂ NC has a narrow size distribution range between 82 nm and 410 nm, and a specific surface area of 41.4 m²/g that is sufficiently high for particle-molecule interactions. Its rheological variables are notably shear-thinning and did not undergo notable fluctuation. The filtrate loss of 1.5 g SDS bearing PEG-SiO₂ NC at 78 °F and 250 °F was only 5.4 ml and 9.6 ml, against 10.2 ml and 20.5 ml of the WBMs, respectively. High dispersion stability and high thermal stability aided its excellent viscosity and filtration control performance. Moreover, optimum rheological properties for the SDS modified PEG-SiO₂ NC drilling muds with Bingham plastic and Ostwald-de-Waele models occurred with mud composition CD3 (CD3 = 1.5 g SDS modified PEG-SiO₂ NC + WBM). Thus, this study can help to understand the applications of this nanocomposite as a potential viscosifier and filtrate loss control material for WBMs.     

Properties of the forpolymer of N-vinylpyrrolidone with itaconic acid, acrylamide and 2-acrylamido-2-methyl-1-propane sulfonic acid as a fluid-loss reducer for drilling fluid at high temperatures

The forpolymer of N-vinylpyrrolidone (NVP), itaconic acid (IA), acrylamide (AM) and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) was synthesized through free-radical polymerization and was characterized using Fourier transform IR spectroscopy. The colloidal properties of the drilling fluid were investigated in the form of fresh-water or salt-water mud. It was found that the NVP–IA–AM–AMPS forpolymer had strong effects on the properties of the mud. The filtrate volume decreased with the increase of the forpolymer concentration before or after the aging test at 220 °C, and the filtrate volume after the aging test was larger than that before the aging test, but was still very small compared with the corresponding base mud. In addition, the rheological properties of both fresh-water mud and salt-water mud were modified by the forpolymer. The particle size data demonstrated that the average size of the clay particle after the aging test was larger than that before the aging test and that the particle size of the fresh-water mud was narrower compared with that of the salt-water mud before and after the aging test, respectively. The drilling fluid containing the forpolymer had an excellent tolerance to salt and high temperature. Received: 13 September 2000/Accepted: 9 January 2001     

A Study of the Influence of Nanoparticles on the Properties of Drilling Fluids

The effect of nanoparticles with different compositions and sizes on the rheological properties, filtration losses, and lubricating ability of drilling fluids has been experimentally studied. Nanoparticles of silicon, aluminum, and titanium oxides have been examined, while an aqueous bentonite suspension with a solid phase mass fraction of 5% has been used as a basic model of a drilling fluid. The concentrations and sizes of nanoparticles in the drilling fluids have been varied from 0.25 to 2 wt % and from 5 to 100 nm, respectively. It has been shown that the addition of nanoparticles substantially changes the properties of the drilling fluids. In contrast to suspensions of particles with macro- and microscopic sizes, the rheological parameters, filtration losses, and lubricating and sticking abilities of the suspensions containing nanoparticles depend on the size and nature of the latter and vary markedly already at low nanoparticle concentrations.     

甲基葡萄糖苷对钻井液性能的影响

甲基葡萄糖苷对钻井液性能的影响;甲基葡萄糖苷;抑制作用;膜效率;活度;钻井液     

Study on Nuclear Magnetic Resonance Logging T2 Spectrum Shape Correction of Sandstone Reservoirs in Oil-Based Mud Wells

The oil-based mud filtrate will invade the formation under the overbalanced pressure during drilling operations. As a result, alterations will occur to the nuclear magnetic resonance (NMR) response characteristics of the original formation, causing the relaxation time of the NMR T₂ spectrum of the free fluid part to move towards a slower relaxation time. Consequently, the subsequent interpretation and petrophysical evaluation will be heavily impacted. Therefore, the actual measured T₂ spectrum needs to be corrected for invasion. For this reason, considering the low-porosity and low-permeability of sandstone gas formations in the East China Sea as the research object, a new method to correct the incorrect shape of the NMR logging T₂ spectrum was proposed in three main steps. First, the differences in the morphology of the NMR logging T₂ spectrum between oil-based mud wells and water-based mud wells in adjacent wells were analyzed based on the NMR relaxation mechanism. Second, rocks were divided into four categories according to the pore structure, and the NMR logging T₂ spectrum was extracted using the multidimensional matrix method to establish the T₂ spectrum of water-based mud wells and oil-based mud wells. Finally, the correctness of the method was verified by two T₂ spectrum correction examples of oil-based mud wells in the study area. The results show that the corrected NMR T₂ spectrum eliminates the influence of oil-based mud filtrate and improves the accuracy of NMR logging for calculating permeability.     

Enhanced cuttings transport efficiency of water-based muds using (3–Aminopropyl) triethoxysilane on polypropylene-nanosilica composite

The lifting of cuttings has been a challenging phenomenon in the petroleum industry for a long period, given the complexity of different cuttings types and their high tendency to gravitate to the low side of the hole. Although many additives have been applied to improve the efficiency of water-based muds (WBMs) for cuttings transport, only a few success was recorded in the application of these additives once evaluated under different field situations. In this study, a new WBM formulated by nanocomposites was proposed to lift cuttings out of the annulus during drilling. Series of characterization, rheological, filtration loss, and cuttings transport tests were performed on the drilling muds formulated by (3-Aminopropyl) triethoxysilane modified polypropylene-silica nanocomposite (PP-SiO₂ NC-NH₂). The cuttings transport test was conducted in a 16-ft. annulus using 9.5 ppg muds, a 60°-hole angle, and annular velocities between 66.1 and 138.6 ft/min at different PP-SiO₂ NC-NH₂ concentrations of 0.4, 0.5, 0.8, and 1.2 ppb. The performance of 0.5 ppb PP-SiO₂ NC-NH₂ + WBM on CTE was evaluated and compared with that of WBM + 0.5 ppb of partially hydrolyzed polyacrylamide (PHPA) at five different hole angles from 90 to 0°. The results of zeta potential showed that the PP-SiO₂ NC-NH₂ was stable. The rheological and filtration properties were enhanced by the inclusion of PP-SiO₂ NC-NH₂ in the WBM. There exists a better enhancement in the CTE of PP-SiO₂ NC-NH₂ + WBM over that of PHPA + WBM at 0.5 ppb. The highest cuttings lifted to the surface occurred in a vertical well, followed by 90°, 30°, 60°, and 45° wells. An increase in annular velocity and the orbital motion of the drill pipe by mechanical action increased the CTE of the nanocomposite more than the rest mud samples. It seems the PP-SiO₂ NC-NH₂ can be more effective than the PHPA for the drilling process and can improve the cuttings lifting performance of WBMs but caution should be exercised to ensure its proper dispersion in drilling muds.     

CFD Simulation of Rheological Model Effect on Cuttings Transport

Foam, as a non-Newtonian fluid, plays an important role in the underbalanced drilling technique in oil field development. The rheological properties of drilling fluids, such as foam, have a direct effect on flow characteristics and hydraulic performance. Two rheological models—the Herschel–Bulkley model and power law—were fitted to two foam systems in this study. Computational fluid dynamics (CFD) was used to simulate the effect of the rheological models on solid–liquid (cuttings transport) hydraulics in concentric and eccentric annulus during the foam drilling operation. The simulation results are compared to the experimental data from previous studies. The results of CFD using the power law model are in good agreement with experimental results in horizontal annulus with respect to the Herschel–Bulkley model with relative error less than 8%. Thus, for CFD cuttings transport for simulations in inclined and horizontal annulus, it is best to use the power law's rheological model parameters.     

Synthesis and Evaluation of Novel Polymeric Phosphate Surfactants for Oil-Based Muds

(Mono, di) alkyl, aryl phosphate-ethoxylate were prepared from coal-tar-phenol. The synthesized ethoxylates were evaluated as water-in-oil emulsifiers in oil-base mud, one type of the drilling fluids used to drill for oil and gas wells by the rotary method. This study presents a new trend of disposal and reuse of cao-tar phenol, a byproduct that causes environmental problems. The newly prepared compounds were confirmed by FTIR and molecular weight determination. Surface properties of the newly prepared ethoxylates were studied via surface tension, emulsion stability, cloud points, critical micelle concentration, and hydrophile-lipophile balance. Also, rheological properties, filtration, and electrical stability were studied to the oil-base mud formulated with the newly prepared emulsifiers compared to the reference sample (commercial emulsifier).     

Preparation and application of a glucose graft copolyammonium as shale inhibitor

In the paper, a shale inhibitor, glucose graft copolyammonium (GGPA), was prepared and evaluated by bentonite linear expansion test, anti-swelling experiments, mud ball experiments. The drilling fluid properties were evaluated. Anti-swelling results shows that anti-swelling rate of 0.8% GGPA reaches up to 94.5%. Mud ball experiment and drilling fluid evaluation showed that GGPA has strong inhibitive capability to bentonite hydration swelling. GGPA can control the particle size of bentonite. The inhibition mechanism of the polyamine salt was analyzed by thermogravimetric analysis and scanning electron microscope. The results demonstrate that the GGPA can be adsorbed on clay surface through electrostatic interaction and hydrogen bonds by an anchoring effect and a hydrophobic effect.     

Reversible photorheological fluids based on spiropyran-doped reverse micelles

We describe a new class of photorheological (PR) fluids whose rheological properties can be reversibly tuned by light. The fluids were obtained by doping lecithin/sodium deoxycholate (SDC) reverse micelles with a photochromic spiropyran (SP) compound. Initially, the lecithin/SDC/SP mixtures formed highly viscoelastic fluids, reflecting the presence of long, wormlike reverse micelles. Under UV irradiation, the SP was isomerized to the open merocyanine (MC) form, causing the fluid viscosity to decrease 10-fold. When the UV irradiation was switched off, the MC reverted to the SP form, and the viscosity recovered its initial value. This cycle could be repeated several times without loss of response. The rheological transitions are believed to reflect changes in the lengths of the reverse worms. To our knowledge, this is the first example of a simple, reversible PR fluid that can be made entirely from commercially available components.     

Emulsification properties of a star-shaped anionic surfactant in oil-based drilling fluid

A novel star-shaped sulfonate surfactant, synthesized with triethanolamine, was identified as a hydrophilic emulsifier which could form a stable water-in-oil emulsion. The interfacial film strength was measured by suspension drop method. The emulsification properties of emulsions were obtained by the emulsification rate experiment and demulsification voltage measurement. The emulsion shows an excellent emulsification effect when the addition of star-shaped anionic surfactant into oil-based drilling fluid was 2.0?wt%. In addition, the properties of surfactant in drilling fluid with different adding amounts were studied by rheological properties, thermal stability analysis and filtration experiments. The results show that star-shaped anionic surfactant used as emulsifier can improve the performance in oil-based drilling fluid, which maybe provides a new idea for this type of surfactant.     

Thermo-physical and stability properties of raw and functionalization of graphene nanoplatelets-based aqueous nanofluids

This research aimed to evaluate the thermal viscosity, stability, conductivity and density of coolants including PEG-functionalized graphene nanoplatelets (GNPs) and gum Arabic (GA)-treated GNPs as a base fluid at various temperatures and concentrations. The present study explores the impacts of GNPs functionalized with poly ethylene glycol (PEG) on the colloidal stability and thermophysical properties of water-based PEG-functionalized GNPs suspensions as a new generation of heat transfer fluids. To this end, PEG-functionalized GNPs as a covalent sample and GA-treated GNPs were synthesized and their colloidal stabilities were traced via UV–vis spectrometry. After functionalized, colloidal stability results indicate less sedimentation for covalent samples (less than 10%) that that of noncovalent one (almost 20%) after a 15-day period. In addition, all the thermophysical properties e.g. thermal conductivity, density and viscosity were measured experimentally. Further, it has shown that by loading PEG-functionalized GNPs in the water, the increasing rate of the density and viscosity is not significant, while water-based GA-treated GNPs nanofluids showed higher rates of increase. Interestingly, the water-based PEG-functionalized GNP nanofluids at very low concentration significantly increase the thermal conductivity in comparison with that of non-covalent nanofluid at the same concentration and temperature and defiantly water.     

Fe3O4/poly (acrylic acid) nanoparticles as modifiers for improving rheological and filtration properties of water-based drilling fluids

Drilling fluid is a vital element and is often regarded as the “blood” in the oil industry. Although traditional oil-based drilling fluids have advantages in some harsh cases, the high cost and environmental pollution faced with them limit its application. Water-based drilling fluids (WBDFs) with environmental friendly, low cost, and high performance are important for drilling engineering to solve the problems of low efficiency and wellbore instability caused by poor rheological properties and large filtration loss in drilling operations. In this paper, Fe₃O₄ nanoparticles modified by poly (acrylic acid) (PAA) through 3-(trimethoxysilyl) proryl methacrylate (TMSPMA) were introduced into WBDFs for enhancing their rheological and plugging performance. Rheological tests indicated that the consistency coefficient (K) of the Fe₃O₄/PAA nanoparticles/WBDFs decreased at a higher concentration. Incorporated nanoparticles with a concentration of 0.05?wt %, the WBDFs will exhibit good shear-thinning behavior. The results showed that the best performance for Fe₃O₄/PAA nanoparticles being as a filtration additive in WBDFs was achieved at concentration as low as 0.1?wt %. These results demonstrated that Fe₃O₄/PAA nanoparticles are effective additives for WBDFs.     

新型超支化大分子季铵型抑制剂的制备及性能评价

以二乙醇胺、丁二酸酐为原料,合成端羟基超支化大分子；用环氧丙基三甲基氯化铵进行末端基团改性，引入季铵盐阳离子基团制备了一种新型季铵盐抑制剂HBP-TAC，其结构经红外光谱、核磁和元素分析表征。考察了端基取代度与浓度对抑制膨润土水化膨胀性能影响，并对滚动回收率及与钻井液配伍性进行了评价、实验结果表明：该类抑制剂对膨润土的水化膨胀有一定抑制作用，加入1%多取代HBP-T2，抑制效果能达到95.31%；在高温130℃条件下，页岩滚动回收的一次回收率为91.8%，二次回收率为80.1%；抑制剂与水基钻井液体系相容性较好，并对滤失性有一定改善效果。      

Effect of surfactants on bauxite residues suspensions viscosity

Measurement of the rheological property of bauxite residue samples received from an Australian alumina refinery (red mud and neutralised mud suspension) has been carried out using a Brookfield viscometer. The plant samples were treated with two anionic surfactants (sodium polyphosphate and sodium laurate) in the laboratory and the effect of the surfactants on the residues viscosity was determined. It was found that the addition of sodium laurate, prepared with an excess of sodium hydroxide causes reduction of the viscosity of both red mud and neutralised mud while sodium polyphosphate shows very little effect on either samples. The suspensions exhibit non-Newtonian behaviour and obey the power law model over a range of solid concentrations at 75 °C.     

疏水改性低分子量阳离子聚丙烯酰胺抑制剂的制备及性能评价

针对现有阳离子类抑制剂与钻井液配伍性、抑制性较差的不足,本文以丙烯酰胺、甲基丙烯酰氧乙基三甲基氯化铵、丙烯酸十八酯为原料,以乙醇和乙酸丁酯的混合物作溶剂,采用沉淀聚合法,制备出了疏水改性低分子量阳离子聚丙烯酰胺BJX-1页岩抑制剂。通过研究不同反应条件对BJX-1分子量的影响规律,得出溶剂组成对BJX-1分子量影响最大,可通过调节溶剂组成实现BJX-1分子量的控制。当分子量为1.45×10~5g/mol~1.87×10~5g/mol时,BJX-1的抑制性最好,页岩岩屑120℃热滚回收率约为78%;增加BJX-1中疏水结构单元含量至2%~4%时,可进一步提高BJX-1抑制性,使页岩岩屑120℃热滚回收率高于90%;此时的最佳反应条件为:以乙醇和乙酸丁酯按体积比90∶10~100∶0组成的混合物作为溶剂,引发剂质量分数为0.1%,单体质量分数为3%,在80℃下反应7h。通过对比研究发现,当加量为1%时,BJX-1所对应的页岩岩屑120℃热滚回收率分别比常用小分子阳离子化合物JA-1和高分子量阳离子聚合物DY-1高27.85%和50.06%。BJX-1更能提高钻井液的综合流变性能,使钻井液流变性更加稳定,而且具有优良的高温高压降滤失性。     

Numerical study of the effects of nanofluids and phase-change materials in photovoltaic thermal (PVT) systems

In this paper, the effects of pure water, SiO₂/water nanofluid, and a phase-change material (PCM) as coolants on the performance of a photovoltaic thermal (PVT) system are numerically investigated. The simulations are performed on two modules of PVT with PCM (PVT/PCM module) and without (PVT module). Parameters including PV surface temperature, thermal, and electrical efficiencies of the systems are studied and compared with each other. Moreover, the results of nanofluid as a working fluid is compared with those obtained using pure water. The results show that in the water-based PVT/PCM, the average PV cell temperature is decreased by 16 °C compared to that of the PVT system. This results in an increase of 8% in the electrical efficiency and 25% in the thermal efficiency. In addition, using nanofluid (SiO₂ with 1 and 3 mass% mass fraction) as a coolant in the PVT/PCM system increases the thermal efficiency by 3.51% and 10.40%, for 1 and 3 mass%, respectively, compared to that of the PVT/PCM with pure water as a coolant. This study shows that increasing the melting temperature of the phase-change material leads to an increase in the thermal efficiency of the PVT/PCM system.