High Temperature Cement Research Articles

Preparation and performance evaluation of cationic hydrophobically associating suspension agent for cementing

As exploration and development continue to expand, the number of high-temperature deep wells is on the rise. However, the instability of high-temperature cement slurry remains a significant technical challenge. The suspension agent represents a crucial component in addressing the poor settlement stability of cement slurry. In response to the issues of “thickening at low temperature,” “high-temperature failure” and “difficulty in mixing cement slurry” associated with traditional suspension agents, a cationic hydrophobically associating liquid Suspension agent XFJ was prepared by free radical water-soluble polymerization using sodium ethylene sulfonate, acrylamide, N,N-dimethylacrylamide, N-tert-butylacrylamide and cationic monomer through molecular design. The structure and properties of XFJ were characterized, and the comprehensive performance of the suspension agent in cement slurry was evaluated. The findings demonstrated that the suspension agent XFJ exhibited remarkable heat resistance. When preparing slurry at low temperature, the suspension agent XFJ does not overly thicken the cement slurry, nor does it affect the discharge of the cement slurry or the fluidity thereof. Furthermore, it is capable of maintaining the sedimentation stability of the cement slurry under high temperature. Furthermore, it exhibits excellent compatibility with cement slurry. The suspension agent XFJ has been observed to have no negative impact on the fluid loss and thickening time of the cement slurry when used in combination with different admixtures. Furthermore, the suspension agent has been demonstrated to have good compatibility with different retarders and fluid loss additives. There was no negative effect on the fluidity, fluid loss and thickening time of the cement slurry.

Farmers’ pesticide use and knowledge of aquatic ecosystem contamination with its perceived health risk from contaminated fish consumption in northern Ghana

Pesticide residues in agricultural environments pose significant threats to aquatic ecosystems and human health. Most studies investigate the quantity, environmental, and risk assessment of pesticides in agricultural landscapes. However, farmers’ pesticide use and their knowledge on aquatic ecosystem contamination remain limited and poorly documented. This study evaluated pesticide residue concerns in agricultural settings, focusing on farmers’ uses and knowledge. It addressed pesticide application methods and their effects on aquatic ecosystems and human health through fish consumption. A cross-sectional design was employed and 300 farmers were selected using a multi-stage sampling technique from two agricultural districts – Savelugu Municipal and Tamale Metropolis. The study revealed that maize was most cultivated (29.6 %) with extensive pesticide treatment, particularly herbicides in the study setting. Findings revealed pesticide overuse (22.3 %), mixing of pesticides at the water bodies (24.7 %), improper leftover pesticide disposal methods (39.0 %) and inadequate storage practices (63.0 %) among farmers. About 21.3 % and 74.0 % of farmers have insufficient knowledge of the resulting consequences and the discharge of pesticides into the aquatic environment, respectively. Though the farmers are aware of the detrimental impact of pesticides on human health, there is still a lack of comprehension regarding the indirect consequences for aquatic ecosystems and non-target species. In the study setting, extension services may be important sources of knowledge. Thus, emphasizes the significance of improving extension programmes and utilizing peer-to-peer communication channels to support the adoption of best practices in pesticide management such as licenced high-temperature incinerators and cement kilns with sufficient emission controls. Focused training and outreach programmes designed to enhance farmers' knowledge and implementation of pesticide management plans are urgently needed. These interventions would help in reducing the dangers of pollution to aquatic ecosystems and human health.

Nano-enhancing polymer as a fluid loss additive for ultra-high temperature cementing

The exploitation of ultra-deep oil and gas wells is accompanied by technical problems of ultra-high temperature, especially in the cementing process, which will directly deactivate many admixtures. By in-situ polymerization of the monomers and Nano-SiO2 to improve the temperature resistance, the resulting high temperature resistant composite polymer slurry system can show high efficiency in reducing fluid loss under the high temperature environment of 240℃. The synthesis of the high temperature resistant polymer was characterized by IR and 1H NMR, and its physicochemical properties were analyzed by DLS, GPC, TEM and Cryo-SEM. The synergistic mechanism of Nano-SiO2 on the high temperature resistance of the polymer was revealed by TGA. Using DLS, SEM and EDS, a series of cement slurry systems were used to analyze and compare the effect on fluid loss reduction of different adding methods of Nano-SiO2 in cement slurry at high temperature. The results showed that the grafted Nano-SiO2 polymer maintained effective adsorption capacity at high temperature without degradation, and its fluid loss reduction ability was significantly improved at high temperature. The high temperature resistant composite polymer is strongly adsorbed between cement particles to form a dense and robust spatial network structure. The CSH gel structure is optimized by the particle size gradation of the system, so as to obtain a dense cement cake, which is expected to be applied in high temperature cementing.

Occurrence Mechanism of the Abnormal Gelation Phenomenon of High Temperature Cementing Slurry Induced by a Polycarboxylic Retarder.

The class G oil well cement is a type of special cement that can be subjected to a high temperature formation environment. It was found that the class G cement tail slurry with a low polycarboxylic retarder dosage (usually ≤1% by weight of cement) was more prone to cause the abnormal gelation phenomenon (AGP) than the lead slurry with a high retarder dosage at a high temperature (usually when T ≥ 120 °C). This study aimed at the occurrence mechanism of this unfavorable phenomenon that seriously endangers the cementing security. Results showed that the abnormal gelatinous region underwent premature hydration; namely, the calcium hydroxide and calcium silicate hydrate (C-S-H) content were all higher than the nongelatinous region, while the copolymer content was the opposite. Correspondingly, the theory of "premature hydration and crystal nucleation" was proposed to explain the abnormal gelation mechanism of a cementing tail slurry with an insufficient retarder dosage. Furthermore, a novel functionalized copolymer retarder "PAIANS" was synthesized to alleviate the AGP.

Research on graphene oxide modified polymer as multifunctional filtration reducer for oil-well cementing

Conventional filtration reducers have limited utility in cementing at deep oil and gas fields because of their poor temperature resistance and single function. As a novel multifunctional filtration reducer, graphene oxide-modified polymer GO-PADI was developed by radically copolymerizing 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N, N-dimethyl acrylamide (DMAM) and itaconic acid (IA) between graphene oxide sheets. The microstructure of GO-PADI was confirmed through the utilization of different methods such as fourier transform infrared spectroscopy (FT-IR). The performance evaluation results showed that GO-PADI had the high thermal stability, and could control filtration of cement slurry as conducted by the American Petroleum Institute (API) less than 50 mL, which is 17 % lower than that of the traditional filtration reducer PADI. GO-PADI could increase compressive strength of cement stone by 30.3 %, and decrease elastic modulus by 10.9 % in three-day curing period. GO-PADI has the multifunctional functions of reducing fluid loss, strengthening and toughening, and can effectively improve the engineering performances for high-temperature cement slurry.

Study on effects of metakaolin on the silica-cement slurry performance under ultra-high temperature conditions

In oil and gas exploration and development, the complex working conditions of high temperature and high pressure are increasing, and the strength decline of silica-cement often occurs under such conditions. In this work, the metakaolin influence on the mechanical properties and micro-structure of silica-cement at 240 ℃ and 21 MPa condition is comprehensively studied. XRD technique investigated the chemical composition of cement crystal phase, and SEM observed the micro-morphology of high temperature cement. Results showed that the loading metakaolin has reduced porosity by 12.86%, air permeability while greatly increased nanopore (＜50nm) by 36.47% and increased nanopore (＜10 nm) by 10.34%. Thus, the cement permeability reduced greatly or its anti-channelling enhanced, that is, such results improved the comprehensive performance of cement slurry. These observations, combined with the previously reported the remarkable enhancement of the MK cement compressive strength, represent a major step toward the development of strength retrogression-resistant material at high temperature.

A first-principles insight into thermodynamic and mechanical properties of Xonotlite and Wollastonite phases of high temperature geothermal well cement

This study investigates the thermodynamic and mechanical properties of two common calcium silicate phases, xonotlite (Ca6Si6O17(OH)2) and wollastonite (CaSiO3), in high temperature geothermal well cement using first-principles methods. Various properties, including thermal expansion coefficients, elastic constants, free energy, and entropy, were evaluated with the use of accurate anharmonic approximations at high temperatures. The study found that wollastonite has higher mechanical strength (97 GPa) compared to xonotlite (66 GPa) and lower thermal expansion, with decreasing values at higher temperatures. Volumetric thermal expansion coefficients were also calculated at different temperatures. These results demonstrate the potential of wollastonite as a suitable material for high-temperature cement dehydration processes.

Supplier selection criteria using analytical hierarchy process (AHP)-based approach: a study in refractory materials manufacturers

PurposeRefractory materials are now used in all major industries that demand high-temperature resistance, including petrochemicals, steel, cement and aviation. Businesses must decrease operating costs, enhance product technology, sell well and manage corporate risks in decision-making, notably supplier selection, to be more competitive. The study aims to determine the key criteria and factors of supplier selection and to evaluate the importance of the key factor of the supplier selection criteria for the refractory materials manufacturers in Taiwan.Design/methodology/approachAnalytical hierarchy process (AHP) is used to rank these factors for the decision maker. The AHP method is suitable for verifying refractory supplier selection criteria and providing references. The weighted loss scores for each supplier are then determined using the relative importance as the weights. Supplier selection criteria are ranked using their aggregate weighted loss scores. The provider with the lowest loss score should be chosen.FindingsProduct quality is the most significant of the five criteria: product quality, production technology, logistics capacity, service capability and supplier background. Professionalism is the most significant aspect of product quality, whereas equipment and capacity are vital in manufacturing techniques. The studies also show that the delivery rate is essential for logistics and service capabilities.Practical implicationsThis research has important implications for refractory suppliers in promptly fine-tuning the production and service to enhance customer satisfaction, which is key to business sustainability.Originality/valueThe application of an AHP technique to a real-world industrial issue is what makes this research unique. This research addressed one of the most critical topics in supply chain operations by offering better judgement for supplier selection via the use of suitable quantitative methodologies.

Study on the Oil Well Cement-Based Composites to Prevent Corrosion by Carbon Dioxide and Hydrogen Sulfide at High Temperature

Complex wells with high temperature and the presence of carbon dioxide and hydrogen sulfide acid gas require the use of high-temperature and high-density anti-corrosion cement slurry for cementing operations, and conventional cement slurry does not have the advantages of high density, high-temperature resistance, or corrosion resistance. In order to avoid the severe corrosion of cement slurry by carbon dioxide and hydrogen sulfide at high temperatures, solid phase particles with different particle sizes are combined with polymer materials to form a dense, high-density, high-temperature- and corrosion-resistant cement slurry. In this paper, we consider the use of manganese ore powder weighting agent, composite high-temperature stabilizer, inorganic preservative slag and organic preservative resin to improve the corrosion resistance of cement slurry, design a high-density cement slurry that is resistant to high temperature and carbon dioxide and hydrogen sulfide corrosion, and evaluate the performances of the cement slurry at 180 °C. The results show that the manganese ore powder weighting agent effectively improves the density of the cement slurry. Using composite silica fume with different particle sizes as a high-temperature stabilizer can ensure the rheology of the cement slurry and improve the ability of the cement sample to resist high-temperature damage. The use of slag and resin as preservatives can effectively reduce the corrosion degree in cement slurry. The high-temperature corrosion-resistant cement slurry systems with different densities designed using these materials exhibit good rheological properties, with water loss of less than 50 mL and a thickening time of more than four hours. The compressive strength decreased by less than 5.8% after 28 days at high temperatures. After being corroded by hydrogen sulfide and carbon dioxide (total pressure 30 MPa, 16.7% hydrogen sulfide and 6.7% carbon dioxide) under high temperature (180 °C) for 30 days, the corrosion depth of the cement sample was less than 2 mm, the reduction of compressive strength was low, and the corrosion resistance was strong. These research results can be used for cementing operations of high-temperature oil and gas wells containing hydrogen sulfide and dioxide.

Effects of ethylene diamine tetraacetic acid and calcium nitrate on high-temperature cementing slurry in a large temperature difference environment

In wellhole environments with large temperature differences, high-temperature retarders can slow the strength development of the top of a cement slurry column, thus affecting construction progress and safety of cementing projects. Herein, to address the problem of slow strength development of the top of a cement slurry caused by the addition of the high-temperature retarder GH-8L, the synergistic effect of the co-addition of ethylene diamine tetraacetic acid (EDTA) and calcium nitrate (CN) is considered. The experimental results show that the thickening time of the cement slurry system mixed with EDTA and CN exceeds 300 min at 150 °C and 75 MPa and its strength at 48 h is >14 MPa. As demonstrated by the hydration heat tests, EDTA and CN promote the hydration heat release rate of the GH-8L cement slurry at low temperature. The synergistic mechanism of EDTA and CN in the GH-8L doped cement slurry promotes the initial dissolution of cement particles, significantly increases the content of C-S-H and CH in the hydration products, and promotes the formation of needle-like NO3–AFt ettringite. The cementing slurry, with the co-addition of EDTA and CN, can not only meet the requirements of thickening time and cementing with a large temperature difference but also compressive strength.

Review of high-temperature geothermal drilling and exploitation technologies

Global warming induced by excessive carbon dioxide emission generated from fossil fuels consumption is becoming increasingly severe. Development and utilization of clean and renewable energy is a significant measure to contribute for the carbon neutrality. Geothermal resource is an important clean and renewable energy, because of its advantages of abundant reserves, exploitation without restrictions from the climate and season. Extracting heat from the high temperature geothermal reservoir requires well drilling, completion and fracturing. However, due to some particular conditions in geothermal development, such as high temperature, erosion, leakage, and hard rocks, traditional petroleum well drilling and completion technologies are not well applicable in the geothermal industry. In this paper, the state-of-the-art geothermal drilling, and completion technologies as well as several fracturing methods, such as foam drilling, air hammer drilling, hydrothermal jet drilling, expansion casing technology, high temperature resistant drilling fluid and cement, chemical stimulation and thermal stimulation are comprehensively reviewed. Besides, heat extraction performances of water and CO2 as working fluids in the geothermal system are discussed. A few novel heat extraction methods including closed loop, open loop, enhanced geothermal systems are compared and analyzed. This review is expected to provide suggestions for research fields worthy of study for geothermal drilling and exploitation.

Preparation of calcium hexaluminate porous ceramics by gel-casting method with polymethyl methacrylate as pore-forming agent

Calcium hexaluminate (CA6) porous ceramics were prepared by gel-casting method, with α-Al2O3 and CaCO3 as raw materials and polymethyl methacrylate (PMMA) microspheres as pore-forming agent. The effects of the amount of pore-forming agent PMMA microspheres on the phase composition, bulk density, apparent porosity, flexural strength, microstructure, thermal shock stability and thermal conductivity of CA6 porous ceramics were systematically studied. The pores of CA6 porous ceramics are mainly formed by the burning loss of PMMA microspheres and the decomposition of organic matter. Adding an appropriate amount of PMMA microspheres as pore-forming agent has a positive effect on the thermal shock stability of CA6 porous ceramics. When the amount of pore-forming agent is 15 wt%, the volume density of CA6 porous ceramics is 1.33 g/cm3, the porosity is 63%, the flexural strength is 13.9 MPa, the thermal shock times can reach 9 times, and the thermal conductivity is 0.293 W/(m·K), which can meet the application in refractory, ceramics or high temperature cement industries.

Study on Structural Change and Permeability Development Law of Cementing Slurry before Initial Setting in High-Temperature and Deep Well Environment

Summary To ensure the safe and efficient development of deep and ultradeep natural gas exploration, it is very important to solve the gas channeling problem of cementing annulus cement slurry in a high-temperature environment. In particular, how to ensure that the cement slurry still has a certain strength, good microstructure, and low permeability in the well are the key points. Based on the current high-temperature and deep well conditions, this paper conducts tests on the microstructure, pore size distribution, and permeability of cement slurry samples with different hydration times. The study found that before the initial setting, the cement slurry gradually changed from a liquid state to a “skeleton-pore” solid medium state, and the permeability of the cement slurry gradually decreased and the rate of decrease gradually accelerated. On the whole, conventional cement slurry has good channeling channel and large permeability before the initial setting. Second, the ability of different antichanneling agents to improve the performance of the cement slurry, the period of action, and the mechanism of action are different. Therefore, to further fully consider its influence on the comprehensive performance of the cement slurry in actual use, it is better to use different antichanneling agents with each other, which can significantly improve the gas channeling resistance and cementing quality of high-temperature cementing slurry system.

An accurate correlation between high-temperature performance and cement content of the high-alumina refractory castables

To better guide the composition design of the low-cement high-alumina refractory castables in specific working conditions, in this work, an accurate correlation between their high-temperature performance and cement content was developed and discussed. The results show that both matrix grains and pores show a fine and homogeneous distribution after firing with the cement content in the range of 0–2 wt%. In this range, the liquid distribution is very dispersed, and the matrix is mainly connected by the in situ mullite. Therefore, the maximum working temperature (T0.5) and the creep parameters exhibit a slow linear change with cement content. The liquid amount still shows a linear increase with further increasing the cement content, but it displays a continuous distribution surrounding the matrix grains. This change destroys the direct bonds of mullite and produces many coarse pores, leading to the rapid deformation of the refractories under thermo-mechanical loads. The results suggest that the critical value of cement addition in this refractory is 2 wt% (or ∼10 wt% liquid in the matrix), below which the high-temperature performance can be predicted and kept under control.

Effect of CO2 on the Hydration of Aluminate Cement Under Conditions of Burning Reservoir in Heavy Oil Thermal Recovery

Under conditions of heavy oil thermal recovery, cement sheaths often suffer high-temperature performance degradation and CO2 corrosion. The performance of Class G oil well cement commonly used for cementing, deteriorates significantly at high temperatures and in CO2 environments, which can easily cause accidents. By contrast aluminate cement (CAC), at the same time, has good high-temperature resistance and corrosion resistance. Therefore, this study explored the mechanical properties and permeability of CAC with a high-temperature stabiliser cement slurry system (C1), pure CAC slurry system (C2) and Portland cement with sand cement slurry system (C3) before and after corrosion at 50, 300, 400, 500, and 600°C. The micromorphology, hydration products and pore structure of the cement paste before and after corrosion were analyzed using scanning electron microscopy, X-ray diffraction, thermogravimetry and nitrogen adsorption specific surface area and pore diameter analysis; additionally, the hydration mechanism of CAC under high temperatures and in CO2 environments was explored. The results show that the degree of degradation of the mechanical properties of C1 cement slurry system at high temperatures and under CO2 corrosive environments is significantly lower than that of the C3 cement slurry system. At a curing high temperature of 400°C, the maximum strength of the C1 cement paste reached 36.39 ± 0.37 MPa. The addition of a high-temperature stabiliser improved the mechanical properties of CAC at low temperatures, reduced the formation of C3ASH4 in the cement paste at high temperatures, and improved the strength of the cement paste after high-temperature curing. Compared with the C3 cement slurry system, the C1 cement slurry system had better high-temperature resistance and corrosion resistance and was more suitable for application under conditions of a burning reservoir in heavy oil thermal recovery.

Analysis of the Weight Loss of High Temperature Cement Slurry

The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired phenomenon. Typically, tests on the pressure loss of cement slurry are carried out for temperature smaller than 120°C, and this condition cannot simulate effectively the situation occurring in high temperature wells. For this reason, in this study a series of experimental tests have been conducted considering a larger range of temperatures, different retarders and fluid loss additives. The results show that with an increase in the temperature, the weight loss curve of cement slurry changes from a “two-stage” to a “three-stage” behavior, and the risk of channeling increases accordingly. On increasing the amount of retarder and fluid loss additive, the transition time of cement slurry displays a non-monotonic behavior (it decreases first and then increases). It is found that the optimized retarder and fluid loss additive dosage are 0.2% and 2.5%, respectively.

Synthesis and properties of temperature-tolerance resistant hydrophobically associating polymer suspension agent using response surface method

Aiming at the problem that the oil well cement slurry is easy to settle and lose its stability under high temperature environment, and combining with the characteristics of traditional cement admixtures "thickening at low temperature and thinning at high temperature", we developed a kind of high-temperature resistant cement suspension agent. A quadripolymer suspension agent P-AN18 was synthesized by free radical polymerization using 2-Acrylamido-2-methylpropane sulfonic acid (AMPS), acrylamide (AM), quaternary ammonium salt monomer N-N octadecyl dimethyl allyl ammonium chloride (DMAAC-18), and high-temperature resistant monomer N-Vinyl-2-Pyrrolidinone (NVP). The synthesis conditions were optimized using the response surface method (RSM) innovatively, the response surface graph (3D) showed the influence of independent variables on the rheological properties and density difference of cement slurry influence. The hydrophobic association structure and high-temperature resistance mechanism of P-AN18 were analyzed by infrared spectroscopy, nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), nanoparticle size analyzer, fluorescence probe test and scanning electron microscope (SEM) in a freezing environment. The effect of P-AN18 on maintaining the stability of cement slurry system at high temperature was evaluated. The results showed that the polymer suspension P-AN18 has good temperature resistance and compatibility with cement slurry. At 200 ℃, P-AN18 can keep the cement slurry system stable, and the density difference between the upper and lower part of the solidified cement column is less than 0.01 g/cm 3 . P-AN18 provides a new method for controlling the settlement stability of high-temperature cement slurry, which is expected to be used to improve the safety and cementing quality of deep well cementing. • Predicting density contrast using RSM model. • Characterizing Polymer suspensions from macro and micro perspectives. • Effective prevention of thermal thinning and particle settling of cement slurry.

Techniques and Materials for Optical Fiber Sensors Sealing in Dynamic Environments with High Pressure and High Temperature.

We detail a study of the techniques and sealing materials for optical fiber sensors used in dynamic environments with high pressure (>300 bar) and high temperature (>300 °C). The sealing techniques and materials are the key for the robustness of sensors in harsh dynamic environments, such as large combustion engines. The sealing materials and techniques studied in this work are high-temperature epoxies, metallic polymer, metallic solders, glass solder, cement, brazing and electroless nickel plating. Because obtaining high temperature simultaneously with high pressure is very difficult in the same chamber in the laboratory, we developed a new and simple method to test sealed fibers in these conditions in the laboratory. In addition, some sensors using the materials tested in the laboratory were also field tested in real thermoelectric combustion engines. The study also discusses the methods of fabrication and the cost−benefit ratio of each method.

A novel thermo-thickening viscosity modifying admixture to improve settlement stability of cement slurry under high temperatures

The viscosity of cement slurry decreases when the temperature rises, resulting in bleeding and sedimentation issues caused by high temperatures. The available viscosity modifying admixtures (VMAs) usually thicken cement slurry under low temperatures but their performances deteriorate under higher temperatures. This study proposes a novel thermo-thickening VMA (i.e., a thermo-thickening polymer with strong hydrophobicity, HTP); its thickening ability will become stronger with an increase in temperature. HTP helps to compensate for the consecutive viscosity reduction of cement slurry due to temperature increases and yields a constant-consistency cement slurry over a wide temperature range (up to 165 °C). Most importantly, HTP is able to slash the bleeding water exuded from cement slurry and eliminate the compressive-strength/density differences among the upper-middle-lower hardened cement paste segments, resulting in a significant improvement in the settlement stability of cement slurry. Microscopic observations reveal that the HTP molecules may fully stretch in the cement slurry and integrate with cement hydration products, contributing to the uniform micromorphology of hardened cement paste. The novel thermo-thickening VMA imposes a limited impact on the compressive strength, fluid loss and thickening time of cement slurry and is very compatible with various cement additives. Finally, the high-temperature high-density cement slurry system containing HTP exhibits a constant consistency until rapid setting behavior, which suggests that it has good potential for field applications.

Research Status of Synthetic Oil Well Cement Retarder

Background: Oil well cement retarder is an additive that can extend time for thickening cement slurry, which can ensure the safety of cement. At present, the oil well cement retarder is mainly composed of synthetic materials, which are mainly divided into three major categories: compound polymer, AMPS polymer and non-AMPS. Methods: In this paper, the research status of synthetic oil well cement retarder in recent years is reviewed, and its shortcomings and development trends are analyzed. It is pointed out that the shortage of synthetic retarder mainly lies in problems, including large temperature sensitivity, small temperature application range, abnormal thickening curve, great influence on high temperature settlement stability and cement stone strength development. Conclusion: The development direction of oil well cement retarder is mainly focused on developing intelligent retarder and degradable retarder to meet the cementing needs of oilfields and ensure cementing effect increasing steadily.