Properties Of Cement Slurry Research Articles

The mechanism of mixing and mixing energy for oil and gas wells cement slurries: A literature review and benchmarking of the findings

Well cementing is an integral operation in the oil and gas industry, often considered the key element of wellbore integrity. Improper cement design can trigger well construction risks such as de-bonding and leakage pathways in near wellbore and through annulus. Mixing conditions for cement slurries and how they affect their properties are of great importance which has often been ignored in the cement design. Typical cement slurry properties such as basic rheology, thickening time, compressive strength, shear strength, free water and fluid loss can be directly influenced/modified when mixing conditions change. It is common knowledge in the oil and gas industry that the properties of cement slurry obtained in laboratory do not correlate very well with those in field mixing. This is due to the differences in the mixing equipment, and to the procedures following. However, cement properties mainly measured in laboratory are a critical part of the well integrity assessment process.The main objective of this study is to investigate the mixing energy mechanism and concept in the available literature of oil and gas well cementing, concrete and other industries and identify the existing gaps. The previous literature shows controversial theories when it comes to relying on mixing energy only where shear rate can play an important role. The differences in laboratory and field results are somehow explained as due to extremely different shear rate obtained when using laboratory vs. field equipment.This study shows that there is currently a big gap in the oil and gas literature on the mechanism of mixing. Additionally, some factors such as measuring power consumption, Reynolds number while mixing, kinetic energy, heat dissipation, and effects of the shape of the mixer are totally ignored in preparation of oil and gas cement slurry, whereas they are widely used in mixing non-Newtonian fluid systems in chemical engineering processes and the concrete industry.

Zwitterionic copolymer for controlling fluid loss in Oilwell cementing: Preparation, characterization, and working mechanism

The present investigation deals with the problems of unsatisfactory high‐temperature resistance, inferior salt tolerance and poor comprehensive performance for the domestic fluid loss additives. In this study, a zwitterionic polymer, 2‐acrylamido‐2‐methylpropanesulfonic acid/diallyldimethylammonium chloride/N,N‐dimethylacryl amide/acrylic acid used as fluid loss agent for oil well cementing, was synthesized by free radical polymerization in aqueous solution with ammonium persulfate and N,N,N′,N′‐tetramethylethylenediamine as initiator. The optimal synthesis conditions were obtained via single‐factor variable analysis. The compositions, micro‐structural morphologies, and thermal‐stability of polymer were characterized by FT‐IR, 1H NMR, SEM, DTG, and DSC techniques. The results manifested that the synthetic polymer cement slurry exhibited prominent advantages such as excellent fluid loss control capacity, thermal stability (up to 200°C), salt‐tolerance (saturated brine) and rheological behavior. Even more strikingly, the zwitterionic polymer showed less impact on hardening cement and accelerated the post compressive strength of set cement, verified through the ultrasonic method. Additionally, the mechanism of fluid loss control was found to rely mainly on improving the filter cake quality and the polymer chemisorptions on the surface of hydrated cement through SEM, permeability and TOC analysis. In consequence, the zwitterionic polymer enhanced the comprehensive properties of cement slurry and had great potential to apply in high temperature and high salinity oil‐well cementing. POLYM. ENG. SCI., 57:78–88, 2017. © 2016 Society of Plastics Engineers

Utilization of the heat-treated silicate rocks in the cement and cement slurry manufacturing

Reliable operation of oil and gas wells depends largely on the quality of cementing. Currently lightweight cements with large water-cement ratio are used. To improve the properties of cement slurries we can use fine lightweight additives with the components, which are capable of reacting with the hydration products of clinker component to produce additional amounts of calcium hydrosilicates.An influence of the natural and heat-treated silicate rocks on the properties of cement and cement slurries is studied. It is found that the heat-treated silicate materials have a positive impact on the strength of cements and cement slurries. Research results show that strength of the samples, which contained heat-treated additives, higher than strength of the samples, which contain a corresponding amount of natural additives, at all concentrations of additives and all hardening time.The increased strength of cements and cement slurries based on heat-treated materials is provided, first of all, by reactive decomposition products of clay minerals. During the heat treatment of materials is not only the initial decomposition of minerals, but also the formation of new ones. However, this does not lead to deterioration in the rheological properties of cement slurries.Feasibility of using heat-treated silicate rocks as facilitating additives in the production of cements and cement slurries is confirmed under the conditions of factory laboratory. Cement slurry based on heat-treated kaolin clay meet regulatory requirements for such materials. Values of water separation, setting time, thickening time and bending strength are almost identical within the control bentonite clay-based sample, and the strength of cement slurry at the age of 180 days with the heat-treated additive nearly in 1,5 times higher.

Mechanical Properties and Mechanism of Graphite Oxide Reinforced Oil Well Cement

The effect of graphite oxide (GO) on the mechanical properties of oil well cement was experimentally studied, in view of the zonal isolation failure due to the brittleness. The microstructure of cement stone was observed by SEM, and the mechanism of graphite oxide reinforced cement stone was also investigated. The result illustrates that the mechanical properties of cement was improved significantly due to the addition of GO. When the GO dosage was 0.05%, the compressive strength, flexural toughness, and splitting tensile strength of cement paste at 7 day age were increased by 61.32%, 15.46% and 145.34% respectively. GO had no bad effect on the application properties of cement slurry, and the stability of the slurry was favorable. Besides, GO could reduce the fluid loss of cement slurry. When GO reinforced cement stone undergoes damage under complex stress, if damage occurs within graphite oxide layer, chemical bonds of GO layers must have been broken, and the force between the layers of GO must be overcome when interlaminar peeling happens, which will lead large amounts of energy consumption as well. The mechanical properties of the cement stone were enhanced by the above two aspects. The research results can provide a theoretical reference for solving the brittle fracture of oil well cement stone.

The competitive adsorption characteristics of welan gum and superplasticizer in cement mortar

Welan gum has been widely used in oil cement and grouting materials for its excellent rheological properties and anti-bleeding, and most of all, being friendly to the environment. However, when welan gum was added, the fluidity of mortar decreased sharply, so it should be used together with a superplasticizer to enable good workability. With its powerful charge density in the molecular structure, the competitive adsorption between welan gum and other admixtures happened remarkably during the addition process. Consequently, we experimentally studied on the bleeding rate and rheological properties of cement slurry, fluidity and mechanical properties of mortar with welan gum mixed with superplasticizer, aiming at understanding the competitive adsorption phenomenon by application of welan gum mixed with superplasticizer. By measuring the hydration heat and zeta potential, the mechanism of interaction of welan gum with superplasticizer was deduced and explained. The results showed that it could ensure a good dispersion effect when welan gum is mixed with the two kinds of superplasticizer. Welan gum had little impact on the naphthalene superplasticizer, but did have a substantial influence on polycarboxylate. In practice, adding welan gum after PCE acted with cement for 2 min could effectively avoid the competitive adsorption and then achieve better performance. On this viewpoint for mortar with PCE, new delay release welan gum needs further research and development.

Cement Slurries With Rheological Properties Unaffected by Temperature

Summary The rheological properties of cement slurries usually vary greatly with the change of temperature. This not only increases the complexity of the cementing-job design, but also has side effects on cementing quality. To resolve this problem, a cement slurry with temperature-insensitive viscosity has been prepared by adding a type of thermosensitive viscosity controller (TVC). The experiments show that the cement slurry has relatively temperature-stable rheological properties and shows very little thermal thinning between 20 and 120°C. In addition, the thermally-stable-viscosity cement slurry has good stability and a performance that can meet the demands of well cementing. The cement slurry improves displacement efficiency and cementing design. It has been used successfully in the oil field, and the results show that the cementing-job quality is acceptable.

A theoretical comparison of cement slurry mixing energy in field and laboratory conditions

The cementing of gas wells, especially those used for underground storage, requires precise understanding of cement properties. CO2 sequestration projects require very-long-term cement integrity, which means that the only way to test the properties of cements used in such applications is in the laboratory. It is common knowledge in the oil and gas industry that the properties of cement slurry obtained from laboratory and field mixing do not correlate very well. This is due to differences in the mixing equipment and procedures followed (API laboratory Waring blender vs. field mixer). The dissimilarity has triggered several research studies that have resulted in the mixing energy concept. This study investigates whether the mixing energy concept can be relied on to reconcile laboratory and field results. Results to date suggest that adequate reconciliation cannot be achieved using calculated mixing energies only, and the authors propose the use of shear rate instead. Additionally, this work evaluates the change in shear rates while pumping slurries through coiled tubing and pipes of different diameters, and the associated possible alteration of cement slurry properties. Two different techniques were simulated in the study, namely the API laboratory method and accepted field mixing, which highlighted the need for a review of laboratory mixing practices towards better prediction of field cement slurry properties.

Исследование свойств тампонажных растворов для крепления скважин и боковых стволов с наклонными и горизонтальными участками

Исследование свойств тампонажных растворов для крепления скважин и боковых стволов с наклонными и горизонтальными участками

Strength properties of cement slurries with lightweights applied in oil and gas wells

The article is focused on the cement stone strength properties resulted from lightweight cement slurries that meet GOST-1581-96 (state Standards) requirements. Exfoliated vermiculite, hollow aluminosilicate microspheres (HAMs), diatomite and perlite were used as lightweighting additives.

Influence of Additives to Cement Slurry Rheological Property

Adding different kinds of additives will change rheological properties of cement slurry, same to the concrete. The relationship between fluid shear stress (Γ) and the shear rate (Ds) called rheological properties. In this paper we studied the influence of different additives (Olyacryamide, polycarboxylate superplasticizer , nanoCaCO3) on the slurry rheological properties and the effects of polyacrylamide on cement mortar liquidity.

Effect of Supplementary Cementitious Materials on Rheology of Oil Well Cement Slurries

Abstract This study explores the effects of supplementary cementitious materials (SCMs) on the rheological properties of oil well cement slurries. Four different mineral admixtures including metakaolin (MK), silica fume (SF), rice husk ash (RHA), and class F fly ash (FA) were used as partial replacement for API class G oil well cement. A new generation polycarboxylate-based high-range water reducing admixture was used to improve the fluidity of slurries. A series of flow tests was performed using an advanced shear-stress/shear strain controlled rheometer at three different temperatures, namely 23, 45, and 60°C. Rheological properties of cement slurries were calculated from the resulting flow curves using the Bingham plastic model and the Herschel–Bulkley’s model. Changes in shear stress–shear rate relationships, yield stress, plastic viscosity, and shear thinning/thickening behavior were found to be related to temperature and the type and dosage of supplementary cementitious material. Among the four different mineral admixtures tested, low calcium fly ash was found to achieve most suitable yield stress and plastic viscosity values.

Mechanical and rheological behavior of oil-well cement slurries produced with clinker containing carbon nanotubes

Abstract This paper analyzes the influence of carbon nanotubes (CNTs) on the rheological and mechanical properties of cement slurries used in oil wells. CNTs were grown directly onto the cement clinker by chemical vapor deposition. Cement pastes containing 0.1% and 0.3% of CNT bwoc were compared with CNT-free slurries. Lignosulfonate (0.2% bwoc) was used as dispersant in all cement slurries. Compressive and tensile strength were evaluated at the ages of 48 h and 7 days. The results show that the addition of CNTs does not alter the rheological behavior and stability of the cement slurries considering the dispersant and concentrations employed. On the other hand, the presence of CNTs in the cement slurries increases the tensile strength by approximately 15% at 48 h and 7 days of aging for 0.1% CNT bwoc.

Laboratory Investigation on Performance of Cement Using Different Additives Schemes to Improve Early Age Compressive Strength

It is essential to maintain the oil well cement integrity effectively and economically. The classical literature review of cement slurry preparation has shown high temperature in wellbore has influenced the mechanical properties of cement slurry, especially compressive strength. The compressive strength is the most important parameter when the ability of the cement to perform its necessary functions of down-hole faster placement analyzed. In past, the different additives were used to improve the performance of cement slurry by maintain compressive strength during placement. Laboratory tests carry out by Silica Fume (SF) with dispersants and fluid loss control additives at different concentrations to performed early age compressive test of nondestructive cement slurry through Ultra-Sonic Cement Analyzer (UCA). Measured result showed that 6:34 and 7:48 h aged sample have a maximum compressive strength at temperature above 120°C. It is observed that as concentration of SF increased with combined dispersants and fluid loss additives used to control& enhance compressive strength at above 120°C for the integrity of cement slurry.

The influence of ash from fluidized-bed combustion of lignite on rheological properties of cement slurries

The influence of ash from fluidized-bed combustion of lignite on rheological properties of cement slurries

Mechanical Properties of Cement Slurry by Partially Substitution of Industry Waste Natural Pozzolans

Mechanical Properties of Cement Slurry by Partially Substitution of Industry Waste Natural Pozzolans

Improving Oil well Cement Slurry Performance Using Hydroxypropylmethylcellulose Polymer

At present, high temperature oil wells are known as the most problematic for cementing operation due to limitations of polymer. The polymers are significantly used as mutlifunctional additives for improving the properties of cement slurry. At high temperature, viscosity of polymer decreases and unable to obtained desired properties of cement slurry. It becomes then major cause of fluid loss and gas migration during cementing operations. Thus, it necessitates for polymers that can able to enhance viscosity of slurry at elevated temperatures. This paper is aiming to study Hydroxypropylmethylcellulose (HPMC) polymer at high temperature that is able to increase the viscosity at elevated temperature. In response, experiments were conducted to characterize rheological properties of HPMC at different temperatures (30 to 100 °C). Then it was incorporated as multifunctional additive in cement slurry for determining API properties (fluid loss, free water, thickening time and compressive strength). It was observed that HPMC polymer has remarkable rheological properties that can have higher viscosity with respect to high temperatures. The best concentration of HPMC was found from 0.30 to 0.50 gallon per sack. This concentration showed minimal fluid loss, zero free water, high compressive strength and wide range of thickening time in cement slurry. The results signified that HPMC polymer is becoming multifunctional additive in cement slurry to improve the API properties of cement slurry and unlock high temperature oil wells for cementing operations.

The Research of the Relationship of Cement Slurry Performance Development and Net Early Microscopic Structure

Use concrete pressure testing machine to test the properties of Cement slurry , and conduct the ASTMC1202 penetration test of the properties and MIP which test the properties and microstructure characteristics. Base on the analysis of the relationship of cement strength and permeability, microstructural features. The results show that, with the increase of the permeability of cement slurry net of intensity decreased by 13%; The increase of pore volume total 11%, and the average pore volume rose 5%, cause pore internal loose, strength fell 0.74%; Cement of a few aperture increase to 7 nm, can lead to internal form lots of pore channels, intensity decreased. when the most several aperture is more than 10 nm, cement strength average less than 41.4 Mpa; Age can effectively passivation cement phase crystallization geometrical shape, and effective crystallization refined grain size.

Mechanistic study on carboxymethyl hydroxyethyl cellulose as fluid loss control additive in oil well cement

AbstractThe working mechanism of carboxymethyl hydroxyethyl cellulose (CMHEC, Mw 2.6 × 105 g/mol) as fluid loss control additive (FLA) for oil well cement was investigated. First, characteristic properties of CMHEC such as anionic charge amount, intrinsic viscosity in cement pore solution, and static filtration properties of cement slurries containing CMHEC were determined at 27°C and 70 bar. Effectiveness of the FLA was found to rely on reduction of cement filter cake permeability. Consequently, the working mechanism is ascribed to constriction of cement filter cake pores. Zeta potential measurements confirm that at low CMHEC dosages (0–0.3% by weight of cement, bwoc), adsorption of the polymer onto the surface of hydrating cement occurs. However, at dosages of 0.4% bwoc and higher, an associated polymer network is formed. This was evidenced by a strong increase in hydrodynamic diameter of solved CMHEC molecules, an exponential increase in viscosity and a noticeable reduction of surface tension. Thus, the working mechanism of CMHEC changes with dosage. At low dosages, adsorption presents the predominant mode of action, whereas above a threshold concentration of ∼ 10 g/L (the “overlapping concentration”), formation of associated polymer networks is responsible for effectiveness of CMHEC. Addition of anionic polyelectrolytes (e.g., sulfonated melamine formaldehyde polycondensate, Mw 2.0 × 105 g/mol) to cement slurries containing CMHEC greatly improves fluid loss control. Apparently, the presence of such polyelectrolytes causes the formation of colloidal associates from CMHEC to occur at lower dosages. Through this mechanism, effectiveness of CMHEC as cement fluid loss additive is enhanced. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The Effect of Nanosilica on Cement Matrix Permeability in Oil Well to Decrease the Pollution of Receptive Environment

Nanosilica is the extremely fine silica that has been used for years as cement admixture both in the oil field and in construction and civil engineering industries. Because of its extremely fine nature and high reactivity pozzolanic material, nanosilica has been used to improve slurry impermeability and the mechanical properties of the hardened material. Using nanosilica in slurry composition, improved reological and mechanical properties of cement slurry and set cement. With the adoption of very fine silica particles in cement matrix, porosity and permeability significantly were declined 33.3% and 99% respectively and compressive strength grew from 1486 psi to 3801 psi. Finally the proper amount of nanosilica in slurry composition is presented. The novel slurry formulation with low porosity and permeability and high compressive strength, is suitable in zones where the possibility of gas migration is very high. Index Terms—nanosilica; cement class G; porosity and

Cementing Casing Strings Across Salt Zones: An Overview of Global Best Practices

Summary The global oil and gas industry is being challenged to increase production to meet the rising world energy demand. One of the key areas now being explored and developed to meet this demand are reserves below massive salt formations. To reach these reserves, it is necessary to drill through and case off the salt. Casing and cementing operations in such salt zones can pose particular challenges, ranging from the effect of salt dissolution on cement-slurry properties to the potential dangers presented by salt creep to the integrity of the well and the need to plan for contingencies for potential zones of overpressure or lost circulation. This paper examines and explores the challenges inherent with cementing across salt zones in the global arena. The current best practices for cementing casing strings across salt zones in some of the major subsalt basins of the world, including the North Sea and the Gulf of Mexico, are detailed and discussed. This work should assist those tasked with the construction of wells that have to penetrate significant salt formations to achieve their objectives safely and reliably.