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Статті в журналах з теми "Rock-cement interface":
1
Wang, Lei, Bohang Liu, Hanzhi Yang, Yintong Guo, Jing Li, and Hejuan Liu. "Experimental Study on the Compressive and Shear Mechanical Properties of Cement–Formation Interface Considering Surface Roughness and Drilling Mud Contamination." Energies 15, no. 17 (September 5, 2022): 6472. http://dx.doi.org/10.3390/en15176472.
Анотація:
In a casing-cement sheath-formation system, the cement–formation interface is usually weakly cemented for the residual of drilling mud, in which a leakage path would easily form, threatening the safe operation of underground energy exploitation and storage. To evaluate the compressive and shear mechanical behavior of the cement–formation interface, cement–rock composite cylindrical specimens were prepared. Uniaxial and triaxial compression and direct shear tests were implemented. The flushing efficiency of the rock surface, compressive strength, interface incompatible deformation, parameters of shear strength, and morphology of shear failure surface were acquired and analyzed. Results show that the flushing efficiency of shale surface decreases from 76.7% to 64.2% with the surface roughness increasing from 0 to 2 mm. The flushing efficiency of sandstone is only 44.7%, remarkably lower than that of shale. With the stress condition transforming from uniaxial to triaxial compression, the feature of the stress–strain curves changes from elastic-brittle to elastoplastic, and the compressive strength increases from 20.6~60.1 MPa to 110~120 MPa. The cement part presents noteworthy plastic deformation and several micro shear fractures develop. There is incompatible deformation between cement and rock, which induces interface debonding for almost all the composite specimens. The internal friction angle and cohesive strength both decrease with the increase in pollution degree of drilling mud, and increase with the rise in surface roughness. The shear facture surface is not exactly the rock–cement interface, but usually manifests as a shear zone, in which the rock, cement, and interface all contribute to the final shear failure. The above findings would be valuable for the revealing of cement–formation interface failure mechanism.
2
Tian, Hui, Huajie Liu, Yuhuan Bu, Zihan Chen, and Shenglai Guo. "Effect of Composite Interface Enhancer on the Cementation Strength of Shale Formation–Cement Ring Interface." Processes 12, no. 2 (February 17, 2024): 405. http://dx.doi.org/10.3390/pr12020405.
Анотація:
The cement strength between the cement and the formation is a key factor in determining the cementation sealing capacity. In the shale formation, due to the organic matter content, the cementing quality between the formation and the cement ring is poor, which affects the quality of cementing. It is easy to cause problems such as annulus pressure. To improve the quality of cementing, this paper investigates the effect of amino silane coupling agents, vinyl silane coupling agents and aluminium–zirconate coupling agents on the interface cementation of rock and cement under different conditions. Meanwhile, the effects of different coupling agent compounding on improving the cementation interface cement strength under different temperature and concentration conditions were investigated. This led to the development of a composite interface enhancer. The composite interface enhancer can improve the bond strength between cement and rock by 189.22%. A preflush fluid system was developed to effectively improve the cementation strength of mud shale formations, and its performance was evaluated. The density of the preflush fluid system is 1.15 g·cm−3, and it has good rheology, settlement stability, and filtration loss. In addition, it improves the cementing interface cementing strength between the cement and shale formation.
3
Jenni, Andreas, and Urs Mäder. "Reactive Transport Simulation of Low-pH Cement Interacting with Opalinus Clay Using a Dual Porosity Electrostatic Model." Minerals 11, no. 7 (June 22, 2021): 664. http://dx.doi.org/10.3390/min11070664.
Анотація:
Strong chemical gradients between clay and concrete porewater lead to diffusive transport across the interface and subsequent mineral reactions in both materials. These reactions may influence clay properties such as swelling behaviour, permeability or radionuclide retention, which are relevant for the safety of a radioactive waste repository. Different cement types lead to different interactions with Opalinus Clay (OPA), which must be understood to choose the most suitable material. The consideration of anion-depleted porosity due to electrostatic repulsion in clay modelling substantially influences overall diffusive transport and pore clogging at interfaces. The identical dual porosity model approach previously used to predict interaction between Portland cement and OPA is now applied to low-alkali cement—OPA interaction. The predictions are compared with corresponding samples from the cement-clay interaction (CI) experiment in the Mont Terri underground rock laboratory (Switzerland). Predicted decalcification of the cement at the interface (depletion of C–S–H and absence of ettringite within 1 mm from the interface), the Mg enrichment in clay and cement close to the interface (neoformation of up to 17 vol% Mg hydroxides in concrete, and up to 6 vol% in OPA within 0.6 mm at the interface), and the slightly increased S content in the cement 3–4 mm away from the interface qualitatively match the sample characterisation. Simulations of Portland cement—OPA interaction indicate a weaker chemical disturbance over a larger distance compared with low-pH cement—OPA. In the latter case, local changes in porosity are stronger and lead to predicted pore clogging.
4
Ballivy, Gérard, Brahim Benmokrane, and Pierre Claude Aitcin. "Rôle du scellement dans les ancrages actifs scellés dans le rocher." Canadian Geotechnical Journal 23, no. 4 (November 1, 1986): 481–89. http://dx.doi.org/10.1139/t86-078.
Анотація:
The dimensioning of anchor bars grouted in rock takes into account the mechanical properties of the three components steel, grout, and rock. The allowable bond strength at the rock–grout interface recommended by different national codes is generally selected according to the type of rocks and assuming an ordinary cement grout. In the present approach, the influence of the type of grout on the pull-out strength of anchor bars in a sound rock mass with mechanical properties equal or higher than the grout is considered. This experimental study shows that certain cement grouts can develop pull-out strength clearly higher than those obtained with epoxy grouts for example. Key words: rock mass, grouted anchors, cement grouts, epoxy grouts, pull-out test, creep test. [Journal translation]
5
Holý, Ondřej. "Evaluation of Many Load Tests of Passive Rock Bolts in the Czech Republic." GeoScience Engineering 63, no. 1 (March 1, 2017): 1–7. http://dx.doi.org/10.1515/gse-2017-0001.
Анотація:
Abstract Within the research project “FR-TI4/329 Research and development - creating an application system for the design and analysis of soil and rock anchors including the development of monitoring elements”, an extensive stage of field load tests of rock bolts was carried out. The tests were conducted at 14 locations with varied rock composition. Before the initial tests, a loading stand was designed and constructed. A total of 201 pieces of tensile tests of bolts having lengths from 0.5 up to 2.5 m, a diameter of 22-32 mm, were performed. These were fully threaded rods, self-drilling rods, and fiberglass rods. The bolts were clamped into the cement and resin. The loading tests were always performed until material failure of bolts or shear stress failure at the interface cement-rock. At each location, basic geotechnical survey was carried out in the form of core drilling in a length of 3.0 metres with the assessment of the rock mass in situ, and laboratory testing of rock mechanics. Upon the completion of testing protocols, rock mass properties analysis was performed focusing on the evaluation of shear friction at the grouting-rock interface.
6
Bathija, Arpita P., and Peter J. Boul. "An Integrated Approach to Study Cement-to-Formation Bonding." Energies 15, no. 16 (August 17, 2022): 5949. http://dx.doi.org/10.3390/en15165949.
Анотація:
It is crucial to assess the bond strength of the cement–formation interface while developing novel cements for efficient zonal isolation. An integrated method is presented to investigate the failure mechanism in cement and formation rock under downhole reservoir temperature and pressure conditions using a triaxial experimental setup. The acoustic emission count, strain, and velocity data aid in inferring the fracture process that led to the failure of a specimen. Although most specimens investigated exhibit the three dominant events of compaction, multi-cracking, and sliding, there are variations in the basic structure of each specimen. Furthermore, the insight obtained about the internal structure of the specimen points to its strength and damage tolerance, both of which are vital requirements for bonding. This method can distinguish between a standard cement and modified cement very effectively and help in pairing the appropriate cement formulation for a formation rock.
7
Shishkanova, V. N., M. V. Ivanko, and Andrey Yu Kozlov. "Cullet-Filled Concrete." Materials Science Forum 992 (May 2020): 73–78. http://dx.doi.org/10.4028/www.scientific.net/msf.992.73.
Анотація:
The paper considers how cullet of different particle-size distribution affects the concrete strength. Experiments have proven that large-particle cullet (1.25 cm or larger) could be used as an aggregate; the concrete strength will be on par with those of ordinary natural/crushed sand concrete. The paper proves the feasibility of injecting highly dispersed silica fume in combination with effective polycarboxylate-based superplasticizers in cullet-based concrete mixtures. Highly dispersed silica fume will positively affect the strength characteristics of concrete, as silica fume in cement rock reacts with Са (ОН)2, which is released upon the hydration of the clinker minerals С3S and С2S; the reaction produces very strong compounds. Concretes containing up to 30% silica fume in combination with a superplasticizer will feature very high early strength. Use of strong aggregates with a 30% cullet content can produce strong concretes; after steamed, a concrete containing silica fume and polycarboxylate-based superplasticizer will reach 90% of the graded strength. Cement-rock microstructure studies show that the polymer component of the STACHEMENT 2280 superplasticizer will gradually transcend from the glass grains to the cement rock. The interface between the polymer-coated glass grains and the cement rock is blurred and barely present. This strengthens the glass-rock adhesion and improves the concrete strength. This is why cullet is recommended for use in the production of curb stones.
8
Rezzoug, A., A. Alexis, and P. Thomas. "Écoulement à surface libre dans un massif de sol soumis à la marée : comparaison théorie-expérimentation." Canadian Geotechnical Journal 36, no. 1 (August 8, 1999): 13–20. http://dx.doi.org/10.1139/t98-078.
Анотація:
We analyze analytically and numerically the stress distribution along the plug-rock interface and within an axially loaded plug emplaced in a borehole in rock. Experiments show that the interface strength increases with decreasing plug radius and with increasing plug length. Axial strength decreases as a power law of plug radius. An increase in the modulus ratio (ratio of plug modulus to rock modulus) increases the interface strength, until it levels off at a ratio of about 5.0. For short plugs, the tensile stresses may reach a magnitude significant to be of concern for long-term stability of the plug and of the host rock. Out studies suggest designing friction plugs with a length to radius ratio of at least 8.0. In practice, especially for short-term performance, e.g., emergency flood control or temporary diversions, a ratio of 8.0 may not be necessary or justified. For permanent abandonment plugs, it is essential to reduce the tensile stresses in the plug and in the host rock to a level that will minimize the risk of long-term deterioration. We recommend in situ experiments on larger diameter plugs to assess the validity of the proposed size effect extrapolation obtained in this study. Key words: borehole plugging (sealing), shaft seal design, plug-rock interface strength, axial strength, bond strength, cement grout.
9
Akgün, Haluk, and Jaak JK Daemen. "Design implications of analytical and laboratory studies of permanent abandonment plugs." Canadian Geotechnical Journal 36, no. 1 (August 8, 1999): 21–38. http://dx.doi.org/10.1139/t98-089.
Анотація:
We analyze analytically and numerically the stress distribution along the plug-rock interface and within an axially loaded plug emplaced in a borehole in rock. Experiments show that the interface strength increases with decreasing plug radius and with increasing plug length. Axial strength decreases as a power law of plug radius. An increase in the modulus ratio (ratio of plug modulus to rock modulus) increases the interface strength, until it levels off at a ratio of about 5.0. For short plugs, the tensile stresses may reach a magnitude significant to be of concern for long-term stability of the plug and of the host rock. Our studies suggest designing friction plugs with a length to radius ratio of at least 8.0. In practice, especially for short-term performance, e.g., emergency flood control or temporary diversions, a ratio of 8.0 may not be necessary or justified. For permanent abandonment plugs, it is essential to reduce the tensile stresses in the plug and in the host rock to a level that will minimize the risk of long-term deterioration. We recommend in situ experiments on larger diameter plugs to assess the validity of the proposed size effect extrapolation obtained in this study.Key words: borehole plugging (sealing), shaft seal design, plug-rock interface strength, axial strength, bond strength, cement grout.
10
Jiang, Ji Wei, Jun Li, Gong Hui Liu, Yan Xi, and Wai Li. "Influence of Casing Pressure Test on Seal Integrity of Cementing First Interface." Materials Science Forum 944 (January 2019): 1020–27. http://dx.doi.org/10.4028/www.scientific.net/msf.944.1020.
Анотація:
Casing pressure test is an important link of the oil and gas well cementing, but excessive casing pressure test may cause stress failure or plastically deformation of the cement sheath, and generate micro-annulus on the casing-cement sheath cemented surface, then lose seal integrity of the cement sheath. According to the basic theory of elastoplastic mechanics and considering the volume invariance of plastic strain and the influence of elastic strain on volume change, the Mohr-Coulomb criterion is used to establish the casing-cement sheath-surrounding rock combination model. The paper also derived the formula for calculating the micro-annulus of the casing pressure test, and analyzed the influence of the internal pressure of the casing during the pressure test and the elastic modulus of the cement sheath on the radial contact stress of the cement sheath cementation interface after the cementing operation is completed. Results show that: (1) The generation of micro-annulus of casing pressure test is determined by the pressure increase process and the pressure relief process. The pressure increase process may lead the cement sheath into plasticity, and the radial stress at the interface turns into tensile stress and the micro-annulus could appear at the first interface by the decrease of internal pressure during pressure relief process. (2) The varying internal pressure has a great influence on the fatigue failure of the cement sheath, so the continuous multiple casing pressure test should be avoided after the cementing is completed. (3) Under the condition of maintaining the integrity of the cement sheath, increasing the tensile strength of the cement stone and reducing the elastic modulus of the cement stone can improve the pressure bearing capacity of the first interface during the casing pressure test. The model can provide a theoretical basis for the mechanical parameter design of the cement sheath, and provide guidance for on-site construction to reduce or avoid the risk of failure of the first interface seal integrity for the casing pressure test.
Дисертації з теми "Rock-cement interface":
1
Nguyen, Tien Dung. "Étude de la zone d'interphase " granulats calcaires poreux-pâte de ciment" : Influence des propriétés physico-mécaniques des granulats; Conséquence sur les propriétés mécaniques du mortier." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-00849595.
Анотація:
Ce travail vise à mettre en relation les caractéristiques de la zone d'interphase " granulat-pâte de ciment " avec les caractéristiques de porosité, d'absorption d'eau, de dureté et de rugosité de calcaires poreux.La première partie de ce travail a consisté à étudier l'influence de la teneur en eau et de la dureté des granulats sur la résistance mécanique de mortiers. Les résultats montrent que, pour des calcaires poreux et absorbants, les mortiers fabriqués à partir de granulats à l'état sec sont plus résistants que ceux fabriqués à partir de granulats à l'état sursaturé. La deuxième partie de ce travail a consisté à étudier l'adhésion " roche-pâte de ciment ". Il a été constaté que la rugosité et l'état de saturation de la roche affectent significativement les résistances en traction et au cisaillement des composites.La dernière partie est consacrée à l'étude de la microstructure de la zone d'interphase par la technique d'analyse d'images. L'évolution de la porosité moyenne de la zone d'interphase est liée aux propriétés mécaniques des mortiers par la relation de Féret démontrant ainsi que la résistance à la compression dépend principalement de la mésoporosité de l'interphase. Le gradient de porosité est mis en relation avec le gradient de degré d'hydratation et le gradient de rapport E/C. Ces deux derniers sont calculés en appliquant le modèle de Powers. Les résultats obtenus montrent que pour des calcaires poreux et absorbants, la pâte de ciment et la zone d'interphase des mortiers de granulats secs et de granulats sursaturés ne sont pas équivalentes alors qu'initialement on visait le même rapport E/C.
2
Jobard, Emmanuel. "Modélisation expérimentale du stockage géologique du CO2 : étude particulière des interfaces entre ciment de puits, roche reservoir et roche couverture." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0013/document.
Анотація:
Dans le cadre du stockage géologique de gaz acides, il est impératif de garantir l'intégrité des matériaux sollicités afin d'assurer un confinement pérenne du fluide injecté. Le but de ce travail de thèse est d'étudier, par le biais de modélisations expérimentales, les phénomènes pouvant être responsables de la déstabilisation du système et qui peuvent conduire à des fuites du gaz stocké. Le premier modèle expérimental, appelé COTAGES a permis d'étudier les effets de la déstabilisation thermique provoquée par l'injection d'un gaz à température ambiante dans un réservoir chaud. Ce dispositif a permis de mettre en évidence un transfert de matière important depuis la zone froide (30°C) vers la zone chaude (100°C) conduisant à des modifications des propriétés pétrophysiques. Ces résultats soulignent l'importance de la température d'injection sur la conservation des propriétés d'injectivité du système. Le second modèle, appelé "Sandwich" a permis d'étudier le comportement de l?interface entre la roche couverture (argilite COX) et le ciment de puits. Les expériences batch du modèle Sandwich en présence de CO2 ont permis de mettre en évidence une fracturation de l'interface provoquée par la carbonatation précoce du ciment. Ces résultats soulignent l'importance de l'état initial de la roche couverture dans la séquestration du fluide injecté. Le troisième modèle expérimental est le modèle MIRAGES. Ce dispositif innovant permet d'injecter en continu un flux de CO2 dans un échantillon. Les résultats ont mis en évidence un colmatage partiel de la porosité inter-oolithe à proximité du puits d'injection, ainsi qu'une carbonatation du ciment sous la forme d'un assemblage calcite/aragoniteIn the framework of the CO2 storage, it is crucial to ensure the integrity of the solicited materials in order to guarantee the permanent confinement of the sequestrated fluids. Using experimental simulation the purpose of this work is to study the mechanisms which could be responsible for the system destabilization and could lead CO2 leakage from the injection well. The first experimental model, called COTAGES allows studying the effects of the thermal destabilisation caused by the injection of a fluid at 25°C in a hotter reservoir (submitted to the geothermal gradient). This device allows demonstrating an important matter transfer from the cold area (30°C) toward the hot area (100°C). These results highlight the importance of the injection temperature on the injectivity properties and on the possible petrophysical evolutions of the near well. The second model, called ?Sandwich?, allow studying the behaviour of the interface between caprock (COX argillite) and well cement. Indeed, interfaces between the different rock and the well materials represent a weakness area (differential reactivity, fracturing?). Batch experiments carried out with this device in presence of CO2 show the fracturing of the interface caused by the early carbonation of the cement. The third experimental model, called MIRAGES is an innovative device which allows injecting continuously CO2 in a core sample. Samples made of Lavoux limestone and well cement reproduce the injection well at 1/20 scale. Results show a partial filling of the inter-oolithic porosity close to the injection well, and also the carbonation of the cement according to an assemblage of calcite/aragonite
Частини книг з теми "Rock-cement interface":
1
"Sem investigations of the contact zones between rock surfaces and cement paste." In Interfaces in Cementitious Composites, 29–38. CRC Press, 1992. http://dx.doi.org/10.1201/9781482271256-8.
2
"The influence of rock and cement types on the fracture properties of the interfacial zone." In Interfaces in Cementitious Composites, 145–54. CRC Press, 1992. http://dx.doi.org/10.1201/9781482271256-22.
Тези доповідей конференцій з теми "Rock-cement interface":
1
Gomado, Foster Dodzi, Mahmoud Khalifeh, Mohammadreza Kamali, Arild Saasen, and Jan Aage Aasen. "Sealing Performance of Geopolymer for Plugging and Abandonment; Apple-to-Apple Scenario." In SPE Norway Subsurface Conference. SPE, 2022. http://dx.doi.org/10.2118/209552-ms.
Анотація:
Abstract Sealability of barrier material is required for successful plug and abandonment operations. The emergence of geopolymer as a green alternative to ordinary Portland cement presents an option for well abandonment in a more environmentally friendly manner. Sealability of geopolymer in terms of hydraulic and shear bond strength (key factors in evaluating the interfacial properties of the cement-casing interface) is compared to that of API Class G cement at 25°C and at a pressure of 34.5 bar (500 psi). The hydraulic sealability was measured with a custom-made setup, which allows the measurement to be taken continuously from the curing stage of the various cementitious materials with eliminating any pressure and temperature shocks. Thus, mimicking downhole conditions for the hydraulic sealability behavior of the cementitious materials used in our study. In addition, the push-out test was used to characterize the shear bond strength between the casing-cement interfaces. The volume shrinkage behavior was studied for both materials. The volume shrinkage of the Neat G cement was found to occur very quickly during and after the hydration reaction resulting in a total shrinkage of 2.4% whiles that of the geopolymer undergoes a shrinkage of 2.2%. The shear bond strength of the geopolymer lesser than that of the Neat G cement, it was able to match the Neat G cement in terms of the hydraulic bond strength. This is reveals that the rock-based geopolymer can be an alternative for zonal isolation as well as revealing that hydraulic bond strength and hydraulic sealability should be the main factors for barrier qualification.
2
Zheng, Danzhu, Stefan Z. Miska, and Evren Ozbayoglu. "The Influence of Formation Creeping on Wellbore Integrity." In SPE 2021 Symposium Compilation. SPE, 2021. http://dx.doi.org/10.2118/208442-ms.
Анотація:
Abstract Creep, the time-dependent deformation of rock, will increase the pressure applied on the interface between the cement and formation. The objective of this paper is to study the influence of the formation creeping effect on the cement sheath integrity and zonal isolation. It focuses on the failure behavior of the cement sheath in the long period after drilling. The paper also investigates the changing of mechanical properties of cement to avoid loss of zonal isolation. The interface pressure between the cement and formation cannot be measured directly in the field, so it will be valuable to predict this pressure through alternative methods. A Casing-Cement -Formation System (CCFS) analytical model based on linear-elasticity and Cam-Clay plasticity model was built. The CCFS model includes four layers, casing layer-cement layer- plastic creeping layer and the formation layer. This plastic- transition layer is formed because of formation creeping. The axial stress and tangential stress distribution of the cement sheath were calculated by the CCFS model. The contact pressure between the cement sheath and formation was calculated. Mohr-Coulomb yielding criterion was applied to estimate failure behavior for the cement sheath. Two case studies were performed with the new CCFS model and previous CCFS model that do not consider the formation creeping effect. The comparison between two models showed that without considering the formation creeping effect, we might underestimate failure of the cement sheath. The simulation result by our CCFS analytical model indicated that the creeping effect would make the interface between the casing and cement vulnerable to shear failure. We changed the Young's modulus and Poisson's ratio for the failed case to investigate the influence of mechanical properties of the cement material. The result showed that a lower Young's modulus and higher Poisson's ratio were preferred for improving zonal isolation. Instead of pursuing how creeping happens, this paper accepts formation creeping as a fact in the whole life of the well. The geomechanical impacts of the plastic-creeping formation, although undetectable from the surface observations, may cause detrimental consequences to cement integrity.
3
Manataki, Andriani, Paraskevas Kontis, and Sigbjørn Sangesland. "Investigation of the Microstructure of Bismuth Alloy and its Interaction With Cement and Steel Casing." In ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-103843.
Анотація:
Abstract Well-plugging and abandonment (P&A) of oil and gas wells involve the placement of barrier plugs at critical intervals in order to prevent leak paths between the reservoir and the surface. As per the Oil and Gas UK Well decommissioning Guidelines a barrier material, among all the prerequisites, should also provide an interface seal or bond, preventing flow around the barrier plug at the interfaces with adjacent casing steel or formation rock. So far, the most well-known barrier material is cement. It is well-qualified, but since it has also some limitations, other materials, such as bismuth-based alloys, have been investigated as an alternative to cement. This study focuses on the use of the eutectic BiSn alloy for well plugging, with 58% bismuth (Bi) and 42% tin (Sn). Like all bismuth-based alloys, this alloy expands on solidification, which is considered an important property for improving its sealing capability in a well. In addition, the microstructure resulting from the interactions between the BiSn alloy, cement, and steel casing, will affect the sealing performance. For this purpose, lab tests have been carried out using a small-scale test set-up. By scanning electron microscopy, various microstructures, in the BiSn alloy were observed and correlated with the interaction of the alloy with the steel casing and the presence of cement.
4
Suleymanov, Vagif, Abdulhamid Almumtin, Guenther Glatz, and Jack Dvorkin. "Seismic Reflections of Rock Properties in a Clastic Environment." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207808-ms.
Анотація:
Abstract Generated by the propagation of sound waves, seismic reflections are essentially the reflections at the interface between various subsurface formations. Traditionally, these reflections are interpreted in a qualitative way by mapping subsurface geology without quantifying the rock properties inside the strata, namely the porosity, mineralogy, and pore fluid. This study aims to conduct the needed quantitative interpretation by the means of rock physics to establish the relation between rock elastic and petrophysical properties for reservoir characterization. We conduct rock physics diagnostics to find a theoretical rock physics model relevant to the data by examining the wireline data from a clastic depositional environment associated with a tight gas sandstone in the Continental US. First, we conduct the rock physics diagnostics by using theoretical fluid substitution to establish the relevant rock physics models. Once these models are determined, we theoretically vary the thickness of the intervals, the pore fluid, as well as the porosity and mineralogy to generate geologically plausible pseudo-scenarios. Finally, Zoeppritz (1919) equations are exploited to obtain the expected amplitude versus offset (AVO) and the gradient versus intercept curves of these scenarios. The relationship between elastic and petrophysical properties was established using forward seismic modeling. Several theoretical rock physics models, namely Raymer-Dvorkin, soft-sand, stiff-sand, and constant-cement models were applied to the wireline data under examination. The modeling assumes that only two minerals are present: quartz and clay. The appropriate rock physics model appears to be constant-cement model with a high coordination number. The result is a seismic reflection catalogue that can serve as a field guide for interpreting real seismic reflections, as well as to determine the seismic visibility of the variations in the reservoir geometry, the pore fluid, and the porosity. The obtained reservoir properties may be extrapolated to prospects away from the well control to consider certain what-if scenarios like plausible lithology or fluid variations. This enables building of a catalogue of synthetic seismic reflections of rock properties to be used by the interpreter as a field guide relating seismic data to volumetric reservoir properties.
5
Feneuil, Blandine, Elie N'gouamba, Idar Larsen, and Ragnhild Skorpa. "Investigation of the Formation and Detection of Casing-Cement Debonding in Small Scale Samples." In ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-104758.
Анотація:
Abstract In oil and gas wells, cement is generally placed in the annulus between the steel casing and the rock formation to avoid migration of fluids from the formation to the well. Though, during the operation of the well, casing dilatation and contraction may lead to the loss of the sealing ability of the cement annulus: casing dilatation tends to induce cracks in the cement, while casing retractation may create casing-cement debonding (microannulus). At the end of the well’s life, when the well is to be abandoned, it is essential to be able to evaluate the integrity of the cement, to decide whether the cement annulus must be repaired or replaced during the plugging operation. In this study, we investigate the use of a pulse-echo and a pitch-catch ultrasonic tools to assess the severity of cement-casing debonding. In the first stage, we measure the evolution of acoustic logs just after the sample preparation. We compare the evolution of the logging curves with measurements of the cement strength with Ultrasonic Cement Analyzer. We observe that for the samples cured at room temperature and pressure, the quality of the bonding first increases before the setting time, then tends to decrease due to debonding. In the second stage, we simulate defects at the casing-cement interface by placing tape stripes of different thickness. We observe how these defects affect the acoustic logs and observe the morphology of the defects on Computed Tomography pictures, to analyze the relation between the logs and the geometry of the microannuli.
6
Wagner, Paul, Kris Ravi, and Michael Prohaska. "Real-Time Monitoring of the Effect of CO2 on the Cement Sheath." In SPE Trinidad and Tobago Section Energy Resources Conference. SPE, 2021. http://dx.doi.org/10.2118/200931-ms.
Анотація:
Abstract Global warming is one of the most significant issues the world is facing. Capturing carbon dioxide from the atmosphere or industrial processes and storing it in geological formations (carbon capture and storage, CCS) can help counteract climate change. Nevertheless, the interaction between well barrier elements such as cement, casing, tubulars, packers, and valves can lead to possible leakages. To accomplish successful carbon dioxide sequestration, injecting the carbon dioxide in its supercritical state is necessary. The supercritical carbon dioxide can corrode steel and elastomers and react with the calcium compounds in the cement, dissolving them and forming calcium carbonate and bicarbonate in the process. This carbonation can lead to channels forming on the cement-to-rock interface or cracking due to the carbonate precipitation, resulting in a loss of well integrity. This study focusses on finding ways that enable the continuous monitoring of cement integrity, under in-situ conditions, in a lab setup. The construction of an autoclave, capable of withstanding supercritical conditions of carbon dioxide, facilitates the in-situ monitoring. This autoclave also makes CT-scans of the pressurized sample possible, as well as acoustic measurements, using state-of-the-art piezo elements. The first tests will establish a baseline using neat Class G Portland cement to verify the design and sensors. The set up consists of a rock core in the middle of the autoclave surrounded by a cement sheath. A prepared channel in the center of the core expedites the distribution of the carbon dioxide. Once the ability of the sensors to monitor the integrity is verified, different cement compositions and their interaction with supercritical carbon dioxide can be studied. The experimental setup and the procedure discussed here closely simulate the downhole condition. Hence, the results obtained using this setup and procedure is representative of what could be observed downhole. The direction is not to remove the sample from the autoclave for analysis, as is the current industry practice, but to measure cement integrity under in-situ conditions over an extended period of time. Digitalization is powering the in-situ analysis in these tests. The first two tests of this study, using the afore mentioned autoclave, investigated the carbonation behaviour of two Class G Portland cement slurrys, one with a low and one with a high slurry-density. The low-density slurry showed extensive degradation and even the high-density slurry showed carbonation, but only close to the sandstone core. The results from this study can lead to the prevention of leakage of carbon dioxide to the environment and other formations, which defeats the purpose of carbon dioxide sequestration. These results should improve the economics of these wells as well as the health, safety, and environmental aspects.
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Skorpa, R., N. Opedal, M. Khalifeh, and P. Moreira. "Raising the Bar: Why an Industrial Standard for Testing Hydraulic Sealability of Well Abandonment Materials in Laboratory is Essential for Well Integrity." In IADC/SPE International Drilling Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/217934-ms.
Анотація:
Abstract Advances in the properties of OPC and new materials (i.e., mechanical strength, rheological properties, etc.) have shifted the R&D focus towards sealing capability of plugging materials at interfaces between the material and its adjacent medium. The objective of this paper is to outline the importance of new standards for studying hydraulic sealability of barrier materials, with emphasis on interface analysis. This work reviews different procedures used to study hydraulic sealability of barrier materials. Reviewing current standards and procedures for testing and qualifying zonal isolation materials indicates that the focus is mainly on the bulk properties of cement, such as expansion/shrinkage, permeability, and mechanical strength. The benefits of these standards are to provide reproducible results, consistent testing procedures and prevent misunderstandings about behavior of hardened cement in laboratory and field operations. However, interfaces are complex and cannot be tested with current standards, meaning that mechanical properties alone cannot indicate hydraulic sealability. The review process also includes non-setting materials further indicating the need for updated standards. Per today, there is published work on sealability testing on the barrier material interfaces, either towards the surrounding rock or towards the casing. This is of particular importance due to more emerging well types such as CCS, hydrogen storage, geothermal wells, and purpose based well integrity and plug and abandonment. A thorough review of sealability test setups indicates that different research groups have designed setups with similar features, but with variations on scale dimensions, testing protocol and so on. This, in combination with the availability of modern measurement technologies, offers the possibility of enhanced understanding of barrier sealability. As no standards currently describe a uniform testing procedure, direct comparison of results is thus inaccurate, putting the reproducibility and reliability of analyses at risk. Our observation shows that possible considerations for standardization include understanding the effect of dimensional scales, the sequence in the procedure, the duration of testing, the type of casing steel or rock, and the type of invasion fluid besides the amount of released heat of setting material. Therefore, it is highly beneficial that current standards are updated to include sealability analysis, and updates for new and alternative materials, such as geopolymers, settled barite, and metal alloys.
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Ali Khan, Jawad, and Andreas Michael. "Mechanistic Modeling of Wellbore Integrity During CO2 Injection in Deep Saline Aquifers." In SPE International Conference and Exhibition on Formation Damage Control. SPE, 2024. http://dx.doi.org/10.2118/217873-ms.
Анотація:
Abstract In this paper, we examine wellbore integrity during carbon dioxide (CO2) injection in deep saline aquifers, by modeling stress-distribution evolutions within the casing-cement sheath-rock formation (C/CS/RF) system. For our analysis, a mechanistic model is used, which considers a total of eleven ("10 + 1") modes of mechanical degradation assessing each of the three layers of the C/CS/RF system discretely. The integrity of the wellbore is assessed by modeling the casing layer as a thick-walled cylinder and the adjacent-RF layer as a poroelastic solid, accounting for fluid infiltration into and out of the pores in close proximity to the CS layer. The magnitude of the normal-effective stresses at the C/CS and CS/RF interfaces provide calibration parameters for the stress distributions within the intermediate-CS layer, honoring linear elasticity. This novel method is used to determine the initial state of stress within the C/CS/RF system with balanced conditions inside the wellbore, following cement setting. Using input data from the literature, the integrity of the C/CS/RF system is assessed over a 30-year period of bulk-CO2 injection in a closed (bounded) system and an open (unbounded) system subsurface aquifer. In closed-aquifer configurations, disking failures along with radial and shear cracking tendencies are indicated within the CS layer, providing potential pathways for CO2 leakages back into the atmosphere. In open-aquifer configurations, the three aforementioned tendencies for mechanical degradation remain, albeit at a smaller degree. The generated stress distributions demonstrate no indication of inner debonding along the C/CS interface, while the outer-debonding limit is approached on the CS/RF interface, but never exceeded. Moreover, no tensile failures (via longitudinal or transverse-fracture initiation) is expected along the CS/RF interface, nor casing failures (related to compressive/tensile loads, collapse and burst stress loads). Finally, none of the scenarios considered are expected to generate seismic activity along preexisting faults (PEFs) near the injection well.
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Silva, P. H., G. P. Ribas, A. A. Gontijo, G. S. Saliba, J. Lopez, and T. C. Abduani. "Instrumented Pull Test Results in Grouted Split Sets, and Its Comparison with Non-Grouted Test Results in an Underground Manganese Mine – Corumbá/MS - Brazil." In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0464.
Анотація:
ABSTRACT Rock mass friction stabilizers, commonly called Split Sets, were introduced in the metal mines of the United States and Canada in the early 70s. Split Sets can provide support due to friction between the anchor and the rock surface of the boreholes. As Split Sets are inserted in boreholes with slightly smaller diameter than the diameter of the retainers, the radial force is generated by the compression of the anchor by the drill wall, ensuring its efficiency by friction in this contact interface. In order to increase the maximum load capacity of Split Sets, some mining companies opt for grout injection after the installation of the anchors. The present study presents the results of instrumented pull tests performed in Grouted Split Sets and its comparison with the result of tests performed in Split Sets without the application of cement, in an underground manganese mine. A total of 72 tests were performed in 3 different mine locations, with distinct roof geological characteristics, and the results showed an increase of up to four times the initial strength without the application of grout, considering the best scenario. INTRODUCTION Split Sets can provide pressure support due to friction between the anchor and the rock surface of the holes. These were the first types of friction anchors to be used and still are the most widely type operated in underground mining. Split Sets consist of steel tubes sectioned longitudinally, and a steel ring fixed at its lower end, able to apply force to a steel plate that transfers the load to the surface of the excavation. As the Split Sets are inserted in boreholes with slightly smaller diameter than the diameter of the retainers, the radial force is generated by the compression of the tube over the drill wall, ensuring its efficiency by friction in this contact interface (Komurlu and Demir, 2019). According to Komurlu and Demir (2019) the length of the Anchor is an important parameter for load capacities of support with Split Sets. Load capacity increases with bigger length of anchor. In addition to the length of the Split Set, other parameters have a great influence on the efficiency of this type of anchoring. A factor of great impact on the maximum load supported by the Split Set is the drilling diameter. When anchor of the same characteristics and dimensions are used in different diameters of perforation, we realize that there is a tendency to obtain higher maximum loads using smaller diameters, as shown in figure 1 (Tompson et al. 1999).
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Anwar, Rameez, Hossam A. Elmoneim, Syed Hamza Ahmed, and Arif Yousuf. "Ultra-Low-Invasion Non-Damaging Spacer System and Nano-Silicate Based High-Crush Resistant Cement Cures Lost Circulation and Established Well Integrity: A Case Study." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211531-ms.
Анотація:
Abstract The paper presents the design and successful application of an ultra-low invasion non-damaging spacer system followed by nano-silicate based ultra-light cement with high crush strength to produce a competent cement sheath and ensure zonal isolation. The solution was applied in 7inch liner cementing of the candidate well where operator slightly increased the mud weight after gas kick during 8.5inch open hole drilling and encountered total losses. The job was executed with operational optimization and zonal isolation was achieved. The severe-to-total losses (exceeding 200 bbl/hr) were experienced during drilling and liner running. Consequently, circulation could not be established before job. The ultra-low-invasion non-damaging spacer was designed to create a thin, impermeable shield over the pores and micro-fractures of weak, and under pressured formations through differential pressure. It helped to resume circulation and cement pumping even when equivalent circulating density was exceeding the fracture pressure. The 11.6 ppg nano-silicate based high-crush resistant slurry prevented post-placement losses due to early compressive strength development and provided competent cement bonding. The fluids rheology was optimized, and pumping parameters were adjusted to maintain the primary well control during the cementing operation without compromising displacement efficiency. The technology was successfully implemented in the 7" liner cementing of the candidate well where cement evaluation was performed using sonic tools. The cement evaluation confirmed the zonal isolation along the open hole section. The proposed solution helped operator to ensure well integrity in troublesome lost circulation zones which posed well control challenges. It was later validated on four additional wells where the job was executed in similar environment and complete cement coverage was achieved in the section. The spacer system is found to be compatible with all common drilling fluid systems and can bypass the narrow restrictions of liner hanger thus offering an additional value over the conventional loss control fibrous materials. The deposited barrier on fluid-rock interface lifts off with the inflow of the well, eliminating the need for acidizing or other matrix stimulation treatments. This helped in formation impairment and simultaneously reducing time to first production. Additionally, nano-silicate based slurry having high-crush resistant lightweight additives maintained stable slurry with good fluid stability, high early compressive strength and improved bonding. Currently, well is open to production with no zonal isolation or cement integrity issues. The proposed solution will help operators to effectively control losses and enhance zonal isolation in narrow pressure window while achieving the planned cement height along with a competent cement bond. The operators can also avoid the money and time on expensive remedial operations.
Звіти організацій з теми "Rock-cement interface":
1
Um, Wooyong, and Hun Bok Jung. Results of Laboratory Scale Fracture Tests on Rock/Cement Interfaces. Office of Scientific and Technical Information (OSTI), June 2012. http://dx.doi.org/10.2172/1047420.