Overview of the lightweight oil-well cement mechanical properties for shallow wells

Adjei, Stephen; Elkatatny, Salaheldin

doi:10.1016/j.petrol.2020.108201

Cited by 24 publications

(10 citation statements)

References 51 publications

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“…For instance, to control the wellbore fluids and remove the remaining dense drilling mud in deep HPHT wells, the density of the well cement must be increased. The heavyweight cement systems are formulated either by reducing the water-to-cement ratio or using heavyweight agents such as barite and hematite . The simplest method is by reducing the water-to-cement ratio.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Impact of Vermiculite on Hematite-Based Cement Systems

2023

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Heavyweight oil-well cement systems are designed for isolating intervals and supporting the casing at deeper depths where high temperatures and pressures are encountered. The cement slurry should have adequate rheology to ensure efficient placement. Additionally, the hardened cement sheath should be homogeneous with lower porosity and permeability, higher strength, and sufficient flexibility. The effect of vermiculite on hematite-based cement samples has been investigated. The methodology and testing were based on the American Petroleum Institute standards and other recognized recommendations. Fluid properties were characterized by their rheology, while petrophysical and mechanical properties were used to analyze the properties of hardened cement specimens. The vermiculite was used in concentrations of 0.25, 0.5, 1, and 2% by weight of cement (BWOC). The slurries were cured at 3000 psi and 292 °F in cubic and cylindrical molds for 24 h. The results indicate that using 1% BWOC of vermiculite yields the best cement properties. It minimizes the settling of hematite particles to a very low value compared to the base cement as shown by the method of density variation and confirmed by nuclear magnetic resonance. Compared to the base cement slurry, the slurry of 1% BWOC of vermiculite has desirable rheology in terms of plastic viscosity and gel strength. The incorporation of 1% BWOC improves the strength of the cement sheath by 50.7% for the compressive strength and 65% for the tensile strength. Adding 1% vermiculite reduces the permeability and porosity of the cement by 45.8 and 43.5% compared to the control cement. In addition, the 0.7% vermiculite cement is more flexible than the control cement in terms of the elastic properties represented by lower Young’s modulus (a reduction of 33%) and higher Poisson’s ratio (an increase of 2%).

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Section: Introductionmentioning

confidence: 99%

Analysis of the Impact of Vermiculite on Hematite-Based Cement Systems

2023

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“…The CS of the most developed TIC for buildings is less than 2.0 MPa, or even less than 0.3 MPa [ 19 , 20 ]. However, the CS of geothermal cement is generally required to be greater than 6.9 MPa for 24 h [ 21 , 22 ]. (2) Building materials must be fire resistant; the fire resistance of building materials is generally tested in dry, high-temperature conditions (above 600 °C) [ 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Using Fumed Silica to Develop Thermal Insulation Cement for Medium–Low Temperature Geothermal Wells

et al. 2022

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During geothermal energy development, the bottom high-temperature fluid continuously exchanges heat with the upper low-temperature wellbore and the stratum during its rising process. Thermal insulation cement (TIC) can increase the outlet temperature, thus effectively reducing the heat loss of the geothermal fluid and improving energy efficiency. In this study, vitrified microbubbles (VMB) were screened out by conducting an orthogonal test of compressive strength (CS) and thermal conductivity (TC) on three inorganic thermal insulation materials (VMB, expanded perlite (EP), and fly-ash cenosphere (FAC)). Fumed silica (FS) was introduced into the cement with VMBs, as its significant decreasing effect on the TC. Moreover, a cement reinforcing agent (RA) and calcium hydroxide [CH] were added to further improve the CS of TIC at 90 °C. The fresh properties, CS, TC, hydration products, pore-size distribution, and the microstructure of the cement were investigated. As a result, a TIC with a TC of 0.1905 W/(m·K) and CS of 5.85 MPa was developed. The main conclusions are as follows: (1) Increasing the mass fraction of the thermal insulation material (TIM) is an effective method to reduce TC. (2) The CH content was reduced, but the C–S–H gel increased as FS content increased due to the pozzolanic reaction of the FS. (3) As the C–S–H gel is the main product of both the hydration and pozzolanic reactions, the matrix of the cement containing 60% FS and VMBs was mainly composed of gel. (4) The 10% RA improved the cement fluidity and increased the CS of TIC from 3.5 MPa to 5.85 MPa by promoting hydration.

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“…1–4 These stresses and pressures may produce unbalanced forces in the cement stone, causing brittle fracture or the formation of micro-annulus and micro-cracks. 5 The destruction of the downhole cement sheath seriously affects the productivity and production safety of wells. 6,7 With the deepening of oilfield exploration and development, the requirements for the performance of oil well cement are getting higher and higher to meet the needs of cementing technology under complex geological conditions.…”

Section: Introductionmentioning

confidence: 99%