Polymer Drilling Research Articles

Drilling fluid for drilling permafrost rocks

Relevance. The article provides an overview of the problem of drilling wells for oil and gas in conditions of permafrost. When constructing wells for various purposes in conditions of permafrost rocks, special requirements are imposed on the selection of the optimal drilling fluid. Deposits in the permafrost zone have significant differences from conditions where rocks have a positive temperature. Aim. For permafrost conditions, the choice of optimal drilling technology plays an important role. The temperature of the drilling fluid during drilling should be equal to the temperature of the rocks being drilled or be slightly lower. Methods. An analysis of the types of flushing agents used for drilling permafrost has been carried out, and the main technologies used in this case have been considered. A description of the developed flushing liquid is given, and its optimal composition is determined. Results and conclusions. The objectives are solved by developing a clay-free polymer drilling fluid with antifreeze additives, which has a freezing point of minus 7°C. The paper considers the issues of reverse freezing of wells and the use of a thermal case in order to improve the thermal regulation of wells. The choice of thermal insulation equipment is outlined based on predicting temperature changes in the properties of rocks. It was shown that reverse freezing of rocks during the construction of oil and gas wells leads to leaks and collapse of casing columns, freezing of casing columns to the walls of the well, and failure of columns to reach a given design depth. The paper introduces the formula to determine the pressure, at which the stress in the casing reaches the yield point and collapse of the casing occurs. The article shows the diagram of the hydration of ions of the proposed drilling fluid with permafrost and the main causes of complications. Using the laboratory studies, the optimal composition of the drilling fluid was determined. The introduction of the proposed drilling fluid into the practice of permafrost drilling will make it possible to successfully construct oil and gas wells.

Internal blocking and bonding to strengthen the mechanical properties and prevent collapse and leakage of fragmented coalbed methane (CBM) reservoirs by cohesive drilling fluids

Exploiting coalbed methane (CBM) not only provides clean energy but also reduces the risk of gas explosions in coal mining. CBM reservoirs have low mechanical strength due to poor continuity, strong heterogeneity, and rich natural fractures, which bring about wellbore collapse and leakage during the drilling operations of CBM wells. As for fragmented coalbed methane reservoirs, plugging the leakage channel and increasing the density of drilling fluid would result in new collapse problems and leakage. To achieve this, we developed a cohesive fuzzy ball drilling fluid (FBDF) to adhere fragmented coal particles from the discontinuous phase to the continuous phase and strengthen their mechanical properties to prevent collapse and leakage. The microcosmic interaction of coal seams with different fluid systems and adhesive properties have been comprehensively evaluated. The mechanical parameters of coal plugs treated with common potassium chloride drilling fluid (PCDF), polymer drilling fluid (PDF), and FBDF were carefully compared through uniaxial and triaxial experiments. Additionally, the adhesive mechanism of FBDF to coal fines was comprehensively discussed. The results showed that the FBDF would form an elastic mesh structure through hydrophobic association, and bond the small particles of coal debris together to form a stable structure similar to “steel bar-concrete” “macromolecule-particle”. The viscous force on the surface of coal rocks treated by FBDF was higher than that of coal plungers treated by PCDF or PDF. The uniaxial compressive strength of core samples treated by FBDF was increased by 47.1%, while the modulus of elasticity, Poisson's ratio, and brittleness coefficient were decreased by 19.94%, 11.95%, and 4%, respectively, compared to dry coal plug. FBDF also showed preferential plugging and permeability recovery abilities. The FBDF fluids have been successfully applied in two CBM wells characterized by “top leakage and bottom collapse”, neither collapse nor leakage occurred during the drilling process. It provided a new internal blocking and bonding technology for fragmented reservoirs.

Experimental observation for reducing uncut fiber during the carbon fiber-reinforced polymer drilling process

Experimental observation for reducing uncut fiber during the carbon fiber-reinforced polymer drilling process

Performance evaluation of trimethylolpropane ester as high-temperature resistant lubricant for high performance water-based drilling fluids

As drilling operations increasingly target large-displacement wells, horizontal wells, deep wells, and ultra-deep wells, the challenges of excessive drilling resistance and downhole safety have become more prominent. During the drilling process, one of the primary technical methods for preventing and addressing drilling safety issues is the reduction of downhole frictional resistance through the addition of lubricants to the drilling fluid. In this study, a high-temperature and high-salt-resistant drilling fluid lubricant was synthesized using raw materials such as oleic acid and trimethylolpropane. The lubricant exhibited excellent lubrication performance under high-temperature and high-salt conditions. When added at a 1.5% dosage to a 4% freshwater-based slurry, HZ-1 resulted in a 95.2% reduction in the lubrication coefficient. After aging at 200 °C, the HZ-1-containing slurry maintained an 87.9% reduction, and when used with a NaCl dosage of 36%, the slurry still exhibited an 80.5% reduction. Furthermore, HZ-1 exhibited favorable compatibility with both polymer drilling fluid and polysulfone drilling fluid systems. It had basically no effect on the rheological properties of the drilling fluid and reduced filtration loss. Moreover, HZ-1 exhibited a lubrication coefficient reduction rate of 94.5% in freshwater-based slurry and 85.5% in brine-based slurry, outperforming domestic and foreign lubricants. It outperformed these comparative lubricants in terms of lubrication and drag reduction within the same period. The analysis of the lubrication and drag-reduction mechanism revealed that HZ-1, when adsorbed onto a metal surface, formed a hydrophobic and high-strength physical adsorption film. This film prevented direct contact between drilling tools and the friction surface of the well wall, resulting in a significant reduction in the lubrication coefficient. Furthermore, using the drilling fluid system containing HZ-1 lubricant, the wear scar diameter formed on the surface of the four-ball friction experimental body was the smallest, measuring only 0.78 mm. This property significantly enhances the extreme-pressure and anti-wear performance of the friction sub-surface. Consequently, HZ-1 effectively prevents complications such as pressure support, stuck drilling, and high frictional resistance, thereby significantly reducing costs and improving efficiency.

Decreasing the stick-slip vibration during drilling wells using water and polymer drilling mud modified with NanoSiO2 particles

Stick-slip in drilling happens when the drill bit and assembly repeatedly stop and slide due to factors like friction and torque. Using better lubricants in the drilling mud can help reduce friction, lessening stick-slip issues. Nanotechnology has improved drilling mud, making it more resistant to heat and enhancing its viscosity and friction properties. This research extensively investigates the use of nanofluids in drilling processes through thorough lab tests. It examines the impact of introducing NanoSiO2 into two types of drilling mud—freshwater bentonite (FWB) and polymer-based mud—at concentrations of 0.04%, 0.08%, 0.15%, and 0.31% under higher temperatures. The study also explores two methods of dispersing NPs using ultrasonic and solvent techniques. The results show that SiO2 nanoparticles notably improve the flow and filtering abilities of FWB mud but have negative effects on polymer-based mud. A 0.05% addition of NanoSiO2 significantly reduces friction by 52% in FWB mud. In FWB mud, all NanoSiO2 concentrations lead to a 25% decrease in mud cake thickness. Furthermore, adding NanoSiO2 to FWB mud decreases torque, with the most substantial reduction of 40% observed at 0.09% concentration (0.35 gm). On the contrary, incorporating NanoSiO2 into polymer-based mud increases fluid loss volume for all concentrations, reaching up to 36% compared to the base mud. Additionally, filter cake thickness increases eightfold, while lubricity factor doubles. This study offers insights into the advantages of using SiO2 nanoparticles in drilling mud and their impact on the fluid properties during drilling.

Laboratory Study: Comparison of Physical Properties of XCD Polymer Drilling Mud and PHPA

The physical properties of the drilling mud greatly affect the success of the mud in lifting cuttings. The value of the physical properties of the drilling mud that is not in accordance with the required specifications can make cutting removal not optimal. In this study, an analysis of the physical properties of XCD Polymer and PHPA drilling mud will be carried out at temperatures of 100 oF, 200 oF, and 300 oF. This research is experimental which will test the characteristics or physical properties of the mud used. At the beginning of testing the physical properties of the XCD Polymer and PHPA mud using the initial composition of each of these muds, the results obtained did not fit into the mud specifications that had been determined due to the influence of the temperature increase. If you continue to use the same mud composition, the higher the temperature, some of the physical properties of the drilling mud will decrease. To overcome this problem, additives are added to the mud composition at each temperature to be tested. This is done so that the results of testing the value of the physical properties of the mud tested at each temperature are in accordance with predetermined specifications. After re-testing using the composition of the mud that has been added with additives, the results obtained from the two tested muds are the density value of 8.9-11.2 ppg, viscosity of 24-33 sec/qt, plastic viscosity of 20-33 cps, yield point of 21-28 lb/100 sqft, gel strength 10 seconds and 10 minutes respectively of 4-6 lb/100 sq. ft and 6-8 lb/100 sqft, filtration loss of 1.9- 4.6 ml, the thickness of the mud cake is 0.6-1 ml, and the pH is 9-10.

Metoda sidetrackingu oparta na wykonaniu dwóch okien w kolumnach rur o różnych średnicach

While drilling from a vertical shaft the orientation of the diverter is carried out with the help of a magnetometer, leaving an interval of 18 m from the casing. The length of the milled interval could be reduced if a gyroscopic compass is used to orient the BHA. The open borehole section is covered with a strong cement sheath. To avoid magnetic interference, the bridge is drilled down to a depth of 6 m above the bottom of the open interval. A disadvantage of the full casing section milling method is an increased requirement on the strength of the cement bridge for drilling, and the difficulty in finding the head of the lower casing section if it needs to be drilled through after the sidetrack. In many cases, the mechanical drilling rate is limited by the conditions for removing cuttings, and for a horizontal section, the problem of removing cuttings becomes even more complicated. The design of modern milling tools is meant to produce small swarf that does not form clusters and is easily removed from the hole. During milling, it is preferable to flush the well with polymer drilling muds rather than clay muds. Hydrocarbon-based muds are not recommended for milling at all. An alternative to milling the entire casing cross-section is to make windows in the casing. This requires the installation of an oriented whipstock and the milling of the window in several stages. After a whipstock is positioned in the required direction, the stud connecting it with a milling machine of the first stage is cut off. On this basis, the paper proposes a method of sidetracking.

Variations in cold flow and physical properties of Northern Pakistan gas condensate oil after interacting with different polymeric drilling mud systems

Variations in cold flow and physical properties of Northern Pakistan gas condensate oil after interacting with different polymeric drilling mud systems

Deep Eutectic Solvents for Enhancing the Rheological Behavior of Polymers and Clays in Polymeric Water-Based Drilling Fluids

Drilling fluids with high suspending capacity without high viscosity are required in drilling operations, such as horizontal wells and highly deviated wells, with the “cutting bed”. Non-viscosifying rheological modifiers that can enhance the rheological properties of polymer drilling fluids are urgently needed. This study reports the application of a choline-chloride-based deep eutectic solvent (Gly-DES) as a rheological modifier for polymeric water-based drilling fluids. The rheological effects of Gly-DES on bentonite/polymer fluids were evaluated by high-temperature rheological testing, rheological model fitting, and rheological parameter (yield point, fluidity index, gel strength, etc.) analysis. The results showed that 2–4 wt % Gly-DES can improve the rheological properties of polymer drilling fluid in the temperature range of 150 °C. The addition of Gly-DES significantly improved the rheological parameters of drilling fluids, such as the yield point, gel strength, low shear rate viscosity, etc. At the same time, the viscosity of drilling fluids was always stable at different temperatures, which means that Gly-DES can help improve the suspension and cutting carrying capacity of drilling fluids without significantly increasing the viscosity of drilling fluids. Mechanistic analysis revealed that Gly-DES was connected to the polymer and bentonite through hydrogen bonds and ionic bonds, which enhanced the cross-linked network structure of the polymer at high temperatures and promoted the formation of weak gels in Na bentonite suspensions. Gly-DES can simultaneously enhance rheology, inhibit clay hydration, and improve filter cake lubricity and has the potential to be a multifunctional drilling fluid treatment agent.

Comparative Investigation of the Effect of EggshellPowder and Calcium Carbonate as Additivesin Eco-Friendly Polymer Drilling Fluids

Drilling fluid systems have seen the addition of new natural additives in recent years in order to replace traditional additives, improve their rheological properties, and ensure the functionality of the drilling fluid taking into account health and environmental factors. This paper aims to study and compare the effect of the addition of eggshell powder (ESP) as a native and local additive and calcium carbonate (CC) as a traditional and conventional additive on the rheological and filtration properties of the drilling fluid system based on Na-bentonite of the region of Meghnia (Algeria). The test results of 10, 20, and 30 g of CCwerecompared to the same concentrations of ESP.The findings showed that the CC with various concentrations (10, 20, and 30 g) increases the rheological properties and the mud density while it reduces the filter cake and the fluid loss values which are desirable, calcium carbonate had aslightly higher effect on the pH. The obtained results following the addition of ESP with different ratios revealed that the latter has a considerable impact on the plastic viscosity, the yield point, the gel strength, and the cake thickness. Additionally, the effect of the presence of eggshell as an additive in pH, fluid loss, and mud density was studied; we observed a slight increase in the pH, while the fluid loss values decreased. However, the mud density values increased. Beyond 20 g of eggshell, the properties of the mud becomeundesirable. Moreover, this study contributes tonewfindings and suggests that the utilization of waste food and local goods in drilling mud mixtures has a bright future respecting the percentages of use.

Research progress and development tendency of polymer drilling fluid technology for unconventional gas drilling

Unconventional gas includes tight sandstone gas, shale gas, coalbed methane, and natural gas hydrate. With huge reserves, unconventional gas has become the most important natural gas resource successor after the end of the “Easy Oil era.” The drilling fluid is an indispensable wellbore working fluid for unconventional gas drilling with multiple functions. The polymer drilling fluid (PDF) is the most common, longest developed, and most diverse drilling fluid type. With advantages of easily controlled rheology, convenient on-site performance maintenance, and specifically low cost and weak environment pollution, the PDF is gradually replacing the oil-based drilling fluid as the first choice for unconventional gas drilling. The invention of the non-disperse low-solid-content PDF in the 1960s shows that PDF technology has entered the stage of scientific development, and until now, its development has generally experienced five stages: beginning, developing, improving, re-developing, and re-improving. Dozens of polymer additives and PDF systems have been invented and applied, which have solved severe drilling problems, greatly improved drilling efficiency, and promoted exploration and development in difficult oil and gas resources. This paper first reviews the research progress of PDF technology according to the timeline by introducing the composition, feature, advantages, and disadvantages of some representative polymer additives and PDF systems, emphatically the function and mechanism of stabilizing wellbores, lubricating drilling tools, and protecting reservoirs of the biomimetic wellbore-strengthening PDF and amphiphobic high-efficiency PDF in unconventional gas drilling. Then, combining future global demands, especially China’s strategic needs of oil and gas exploration and development, the development tendency of PDF technology is critically illustrated by introducing several potential research directions including intelligent PDF, ecological PDF, and PDF for natural gas hydrate and deep layer gas resources.

Molecular simulation of the rheological properties and shear thinning principles of supramolecular drilling fluids at different burial depths.

In order to investigate the rheological properties and shear thinning principles of supramolecular drilling fluids, the salt-responsive supramolecular ionomer polymers with different components were designed and the change in shear viscosity of supramolecular polymer drilling fluid system with shear rate was studied using the molecular dynamics simulation method. The result indicated that the ionic supramolecular polymer drilling fluid system exhibits better self-assembly performance than the nonionic acrylamide drilling fluid system. Moreover, the drilling fluid system exhibits the best rheological properties and self-assembly performance when the feeding ratios of the three monomers in the two polymers are m : n : o = 5 : 90 : 5 and m : n : o = 30 : 40 : 30, respectively. The shear viscosity recovery rate of the #3 ionic supramolecular polymer drilling fluid system at different burial depths (1-5 km) is >87%, where the shear viscosity is mainly determined at ambient pressure. The shear thinning phenomenon of the supramolecular polymer drilling fluid system occurs because of the combined effect of the polymer molecular orientation and entanglement structure. When the shear rate is above a critical value, the polymer molecules are oriented along the flow field direction, decreasing the shear viscosity. However, when the shear rate is very high, the entanglement structure of the molecules is opened and the mesh structure of the fluids is disrupted, decreasing the shear viscosity of the drilling fluid.

Effect of Bentonite and Polymer Drilling Fluids on Skin Friction of Bored Piles

"ENGINEER", established in 1973 by The Institution of Engineers, is a Journal for dissemination of Engineering knowledge, published quarterly.If you are interested in contributing an Original Technical Paper based on research by the author(s) (intended for Section I) or an Original Article of Professional or Technical interest related to Engineering. (Section II) to this journal please go through the publication checklist which can be downloaded from here.Cover DescriptionCover images show a few views of the Maduru Oya reservoir and construction of right bank canal. The Institution of Engineers, Sri Lanka, acknowledges Eng. L.D. Amila Sanjeewa of the Department of Irrigation for providing images and related information of the project.

Experimental Study on the Potential of Polymeric Drilling Fluid Additives as Hydrate Anti-Agglomerants by Using Rocking Cell

Gas hydrate is a type of ice like crystals, which could widely form and plug the offshore oil and gas pipelines. In order to reduce the cost of hydrate control in oil and gas transportation, search for new anti-agglomerates (AAs) is always needed. In this work, fourteen different types of polymers from drilling fluid additives were selected and their anti-agglomeration ability on gas hydrate was experimentally studied by using a high-pressure rocking cell. The hydrate volume percentage, slider moving range, and moving velocity were measured for evaluation. Two polymers [acrylamide polymer (AAP) and hydrolyzed polyacrylonitrile ammonium salt (HAPS)] were found to be effective to avoid agglomerating at low hydrate concentration (≤6%). AAP and HAPS could prevent plugging, while the hydrate concentration is lower than 15.12% and 16.92%, respectively. It was speculated that the hydrogen bonding capability of the hydrophilic groups, the length of the hydrophobic chains and polymer molecules, and the antagonism of different functional groups might affect the anti-agglomerating performance of polymers.

The study of CFRP variable feed drilling method based on sinusoidal curve

In order to reduce the delamination damage of carbon fiber–reinforced polymer (CFRP) drilling and improve the drilling quality, a variable feed drilling method based on sinusoidal curve is proposed. That means, when drilling at a distance of 1 mm from the hole exit, the feed rate of the drill would be reduced according to the rule of sinusoidal curve. The method is compared with the traditional feed drilling by experiment, and the influence of the variable feed drilling on thrust force, delamination factor, surface quality, and surface roughness of hole wall and exit hole wall morphology are analyzed. The results show that compared with constant-feed drilling, the variable-feed drilling based on sinusoidal curve reduces the thrust force near the hole exit and greatly improves the delamination factor, surface quality, and hole wall morphology at the exit. However, the influence on the hole wall roughness is not particularly obvious.

Application of polymeric drilling fluids for reducing wearing of drill bit

The drill bit or cutting tool is a very important part of the rock drilling operation, it is directly associated with the rate of penetration. Bit wearing has significant involvement of time, labor, and wealth. By identifying the effect of various machine and rock parameters on bit wearing, the optimum working condition can be adopted to achieve high drilling efficiency. In this experimental work, the rate of penetration and parameters of drilling fluids (i.e. type, additives, and concentration, etc.) were optimized to identify their respective impact on the bit wearing of impregnated core diamond bit. The study has been conducted on a laboratory rotary drilling setup. The role of aqueous solutions of carboxymethyl cellulose (CMC), guar gum (GG), and polyacrylamide (PAM) has been examined as polymeric drilling fluid additives on sandstone rock samples and compared with the results of tap water alone as drilling fluid. A significant decrement in bit wearing has been noticed with all additives and the maximum reduction of 70.02% was achieved with CMC fluid additive.

Применение модифицированных гидролизных лигнинов в качестве компонентов буровых растворов на водной основе

The results of an experimental study of the effect of additives of the original and chemical by modified hydrolysis lignin on the rheological characteristics of water-based clay polymer drilling fluids are presented. The content of lignin in solutions varied from 0 to 5 wt. %. It was established by the method of X-ray fluorescence analysis, that the concentrations of toxic elements in the studied components of drilling fluids are at the level of background values and the highest static exchange capacity is observed for lignin samples converted into the sodium form during the modification process. It is shown that the introduction of modified hydrolysis lignin additives into clay based drilling fluids has a significant diluting effect. Therefore, the use of modified hydrolysis lignins as components of drilling fluids is a promising way of utilizing large-tonnage waste from biochemical plants.

Bearing capacity of bored piles made with polymer drilling mud

The main results of the work on the analysis of the possibility of using polyacrylamide drilling muds for the installation of drill piles, barrettes and slurry walls in sandy soils are presented. The results of the study of the possibility of solutions to keep the walls of boreholes from collapse, laboratory studies of the effect of polyacrylamide solutions on the shear strength of soils, as well as the results of field tests of piles with static pulling load are reflected.

Multi-objective optimization of carbon fiber–reinforced polymer drilling process based on grey fuzzy reasoning grade analysis

With outstanding mechanical advantages such as high strength, light weight, high rigidity, low thermal expansion, good resistance corrosion, and high vibration resistance, carbon fiber–reinforced polymer (CFRP) is becoming increasingly popular in the automotive, aerospace, and medical spheres. For the CFRP machining, the biggest drawback is the effect of moisture on the mechanical properties caused by the cooling liquid and tool geometry. The appreciable body of study on the influence of wetness on the mechanical quality of carbon fiber–reinforced plastic has shown that there is no suitable use for lubrication fluids in the composite industry. However, there is a significant impact on the CFRP machining capabilities caused by the geometry of the cutting tool and cryogenic liquid cooling. This paper investigated the optimal choice of the parametric combinations in the CFRP drilling process. The optimization method was proposed using the Fuzzy interference system based on grey relation analysis. The experiment data was designed according to the Taguchi method. The twist angle of the drill, the coolant gas, and the feed rate were considered as the parameter inputs while observing several multi-responses such as thrust force and temperature generated during drilling process. The optimal result, as well as the case with highest grey fuzzy reasoning grade (GFRG), indicated that the low feed rate combined with the high twist angle drill in the hybrid cryogenic CO2-N2 gas condition tended to minimize the value of the response output. The verification experiment results showed a good correlation with the optimal analytical result. The analysis of variance results also showed that the reliability of the data was satisfactory.

ИССЛЕДОВАНИЕ БИОПОЛИМЕРНЫХ БУРОВЫХ РАСТВОРОВ НА ОСНОВЕ ВЫСОКОМИНЕРАЛИЗОВАННЫХ ПЛАСТОВЫХ ВОД ВОСТОЧНОЙ СИБИРИ

Актуальность исследования обусловлена необходимостью полезного использования попутно добываемых с нефтью пластовых вод в качестве основы для приготовления минерализованных соленасыщенных буровых растворов при бурении на месторождениях Восточной Сибири. Цель: исследовать и предложить полимерные системы буровых растворов на основе пластовых вод Восточной Сибири. Объекты: пластовая вода Даниловского и Ичединского нефтегазоконденсатных месторождений, рецептуры и компоненты современных систем полимерных буровых растворов. Методы: инструментальные методы определения параметров буровых растворов по ГОСТ 33213-2014 и РД 39-00147001-773-2004 (фильтрационные и реологические свойства); описание образцов, сравнение характеристик с растворами-аналогами. Результаты. Изучены и описаны физико-химические характеристики пластовых вод; приготовлены полимерные системы буровых растворов на основе чистой и разбавленной пластовой вод; проведены сравнительные исследования приготовленных растворов с растворами, применяющимися в настоящее время при строительстве скважин в Восточной Сибири; представлена описательная характеристика растворов и выдвинуты теории по взаимодействию используемых реагентов с пластовой водой. Установлено, что за счет высокого содержания хлоридов кальция и магния в пластовой воде процесс растворения полимерных реагентов может приостанавливаться, что приводит к полной потере всех вязкостных, фильтрационных и реологических свойств буровых растворов; содержание в пластовой воде в достаточном количестве магния (≥10 г/л) гарантирует получение гидрогель-магниевых буровых растворов; применение попутных пластовых вод позволит снизить материальные и временные затраты, связанные с насыщением раствора на поверхности, одновременно предупредить кавернообразование и в значительной степени предотвратить растворимость соленосных пород.