Long-Term Effects of CO2 Sequestration on Rock Mechanical Properties

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Wahbi Abdulqader AL-Ameri ◽  
Abdulazeez Abdulraheem ◽  
Mohamed Mahmoud
Keyword(s):  
Mechanical Properties ◽  
Carbonate Rocks ◽  
Co2 Sequestration ◽  
Carbonic Acid ◽  
Experimental Results ◽  
Geological Sequestration ◽  
Core Samples ◽  
Sequestration Of Co2 ◽  
Rock Mechanical Properties

The long-term geological sequestration of carbon dioxide (CO2) in underground formations (deep saline aquifers) is the most economically viable option to decrease the emissions of this greenhouse gas in the atmosphere. The injection of CO2 in carbonate aquifers dissolves some of the calcite rock due to the formation of carbonic acid as a result of the interaction between CO2 and brine. This rock dissolution may affect the rock integrity and in turn will affect the rock mechanical properties. The effect of CO2 on the rock mechanical properties is a key parameter to be studied to assess the aquifer performance in the process of geological sequestration and to get a safe and effective long-term storage. The main objective of this study is to address the impact of geological sequestration of CO2 on the mechanical properties of carbonate aquifer and caprocks. In addition, the effect of the storage time on these properties is investigated. In this study, CO2 was injected into the brine-soaked core samples under simulated downhole conditions of high pressure and high temperature (2000 psi and 100 °C). The mechanical properties of these core samples were analyzed using indirect tensile strength (ITS), unconfined compression, and acoustics testing machines. The effect of CO2 sequestration on the engineering operations such as well instability and aquifer compaction will be investigated based on the experimental results. Results showed that CO2 sequestration affected the mechanical properties of the carbonate rocks as well as the caprocks. Long time soaking of CO2 in brine allowed for the formation of enough carbonic acid to react with the cores and this greatly impacted the rock mechanical and acoustic properties. The significant impact of CO2 storage was noted on Khuff limestone (KL), and the good candidate among the carbonate rocks studied here for geological sequestration of CO2 is found to be Indiana limestone (IL). The stress calculations based on the experimental results showed that CO2 may affect the wellbore stability and care should be taken during drilling new wells in the sequestration area. Aquifer compaction based on KL measurements showed that the aquifer will compact 1.25 ft for a 500 ft thick carbonate formation due the CO2 sequestration for 90 days.

scholarly journals Determination of NMR T2 Cutoff and CT Scanning for Pore Structure Evaluation in Mixed Siliciclastic–Carbonate Rocks before and after Acidification

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1338 ◽  
Author(s):  
Mengqi Wang ◽  
Jun Xie ◽  
Fajun Guo ◽  
Yawei Zhou ◽  
Xudong Yang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Experimental Results ◽  
Normal Distribution Function ◽  
Core Samples ◽  
Irreducible Water Saturation ◽  
Significant Difference ◽  
Before And After ◽  
Structure Evaluation

Nuclear magnetic resonance (NMR) is used widely to characterize petrophysical properties of siliciclastic and carbonate rocks but rarely to study those of mixed siliciclastic–carbonate rocks. In this study, 13 different core samples and eight acidified core samples selected amongst those 13 from the Paleogene Shahejie Formation in Southern Laizhouwan Sag, Bohai Bay Basin, were tested by scanning electron microscopy (SEM), micro-nano-computed tomography (CT), and NMR. SEM and CT results revealed a complex pore structure diversity, pore distribution, and pore-throat connectivity in mixed reservoirs. Sixteen groups of NMR experiments addressed changes in these properties and permeabilities of mixed siliciclastic–carbonate rocks before and after acidification to determine its effects on such reservoirs. NMR experimental results showed no “diffusion coupling” effect in mixed siliciclastic–carbonate rocks. Distributions of NMR T2 cutoff values (T2C) are closely related to the pore structure and lithologic characteristics before and after acidification. The T2C index separates irreducible and movable fluids in porous rocks and is a key factor in permeability prediction. Centrifugation experiments showed that, before acidification, the T2C of mixed siliciclastic–carbonate rocks with 60–90% siliciclastic content (MSR) ranged widely from 1.5 to 9.8 ms; the T2C of mixed siliciclastic–carbonate rocks with 60–90% carbonate content (MCR) ranged from 1.8 to 5.6 ms. After acidification, the T2C of MSR ranged widely from 2.6 to 11.6 ms, the T2C of MCR ranged from 1.5 to 5.6 ms, and no significant difference was observed between MCR reservoirs. Based on an analysis of the morphology of NMR T2 spectra, we propose a new T2 cutoff value prediction method for mixed siliciclastic–carbonate rocks based on a normal distribution function to predict various T2C values from morphological differences in NMR T2 spectra and to calculate the irreducible water saturation (Swir), i.e., the ratio of irreducible total fluid volume to effective porosity. The reliability of the proposed method is verified by comparing predicted T2C and Swir values with those from NMR experimental results. New experiments and modeling demonstrate the applicability of NMR for the petrophysical characterization of mixed siliciclastic–carbonate rock reservoirs. Our results have potential applications for identification and evaluation of mixed siliciclastic–carbonate rock reservoirs using NMR logging.

Long-term effect of recycled aggregate on microstructure, mechanical properties, and CO2 sequestration of rendering mortars

2022 ◽  
Vol 321 ◽  
pp. 126357
Author(s):  
Artur Spat Ruviaro ◽  
Laura Silvestro ◽  
Fernando Pelisser ◽  
Afonso Rangel Garcez de Azevedo ◽  
Paulo Ricardo de Matos ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Co2 Sequestration ◽  
Term Effect ◽  
Recycled Aggregate ◽  
Long Term Effect

Study on Strength, Shrinkage and Creep of Concrete Containing Ultrafine Fly Ash Composites

2012 ◽  
Vol 450-451 ◽  
pp. 162-167
Author(s):  
Bao Ju Liu ◽  
You Jun Xie
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Drying Shrinkage ◽  
Experimental Results ◽  
Steam Curing ◽  
Curing Conditions ◽  
Shrinkage And Creep

At steam curing and moist curing conditions, the mechanical properties of concrete with different fineness and different proportions ultrafine fly ash-slag composite were studied. The experimental results indicated that the addition of ultrafine fly ash-slag composite had improved the long term mechanical properties of steam-cured concrete. The concrete with ultrafine fly ash-slag composite has lower drying shrinkage and creep compared to that of control concrete.

Evaluation of Rock Mechanical Properties Alteration During Matrix Stimulation With Chelating Agents

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Assad Barri ◽  
Mohamed Mahmoud ◽  
Salaheldin Elkatatny
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
Carbonate Rocks ◽  
Chelating Agents ◽  
Ethylenediaminetetraacetic Acid ◽  
Chelating Agent ◽  
Well Stimulation ◽  
Before And After ◽  
Rock Mechanical Properties ◽  
Carbonate Formations

Well stimulation using acidic solutions is widely used to treat carbonate formations. The acidic fluids remove the near-wellbore damage and create channels around the wellbore by dissolving fraction of the carbonate rocks. Many stimulation fluids have been used such as hydrochloric acid (HCl) acid, organic acids, and chelating agents to stimulate carbonate reservoirs. Wormholes that are created by these fluids are very effective and will yield negative skin values and this will enhance the well productivity. In addition to the wormhole creation, the diffusion of these fluids inside the pores of the rock may create significant and permanent changes in the rock mechanical properties. These changes can eventually lead to weakening the rock strength, which may lead to future formation damage due to the wellbore instability. In this paper, the effect of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) chelating agents on the carbonate rocks elastic properties was investigated. The effect of wormholes created by chelating agent on the rock mechanical properties was investigated. Computed tomography (CT) scan and acoustic measurements were conducted on the core samples before and after matrix stimulation treatments. Experimental results showed that the mechanical properties of strong rocks such as Indiana limestone (IL) cores were not affected when chelating agents were used to stimulate those cores. On the other hand, less strong rocks such as Austin chalk (AC) show significant alteration on the rock elastic properties when chelating agents were used as stimulation fluids.

Modelling of changes in physical and mechanical properties of structural materials during long-term exposures at elevated temperatures

2004 ◽  
Vol 120 ◽  
pp. 191-199
Author(s):  
J. Kohout
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Degradation Mechanism ◽  
Physical And Mechanical Properties ◽  
Structural Materials ◽  
Experimental Results ◽  
Polymer Materials ◽  
Polyamide 66 ◽  
Glass Fibre Reinforced

Long-term exposures of various industrial structural materials at sufficiently elevated temperatures cause substantial changes in materials structures and, consequently, substantial changes in their physical and materials properties. The paper is focused to the influence of thermodegradation of glass-fibre-reinforced polyamide 66 in dry air and gear oil on its mechanical properties. As the thermodegradation of polymer materials is diffusion controlled process, the paper starts with the description of water diffusion in tested material. Then a very simple degradation mechanism is proposed for modelling the main features of real degradation processes. Regression functions describing the changes in mechanical properties of polyamide details during exposure are verified by the fit of experimental results. In the end of the paper some general considerations about the changes in other structural materials during exposures are done and supported by some experimental results.

Stability of Microstructure and Mechanical Properties of GH984G Alloy during Long-Term Thermal Exposure

2013 ◽  
Vol 747-748 ◽  
pp. 647-653 ◽  
Author(s):  
Ting Ting Wang ◽  
Chang Shuai Wang ◽  
Jian Ting Guo ◽  
Lan Zhang Zhou
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Power Plants ◽  
Low Cost ◽  
Thermal Exposure ◽  
Tensile Tests ◽  
Experimental Results ◽  
Σ Phase ◽  
Microstructure And Mechanical Properties

A low cost Ni-Fe-based wrought superalloy for 700 advance ultra-supercritical coal-fired power plants was developed. The stability of microstructure and mechanical properties of this alloy during long-term thermal exposure was investigated by SEM,TEM and tensile tests. The experimental results showed that the major precipitates in the alloy were spherical γ, MC and discrete M23C6 distributing along grain boundary after the long-term exposure at 700 and 750 and no harmful phases, such as σ phase and η phase, were found. However, after exposure at 800 up to 3000 h, small amount of lath-like η phase precipitated at grain boundary by consuming the surrounding γ. The η phase exhibited a fixed orientation relationship with the γ matrix. During thermal exposure γ coarsened with increasing the exposure time and exposure temperature. In addition, all major phases and their stability temperature ranges were calculated by JMatPro and these results were confirmed by the experimental results. The 700 tensile tests revealed that the alloy after exposure at 700 and 750 for 3000 h exhibited excellent ductility and strength. Therefore, the GH984G alloy possessed excellent stability of microstructure and mechanical properties between 700 and 750 up to 3000 h, and it is a promising material for 700 advance ultra-supercritical coal-fired power plants.

Effect of Cryogenic Treatment Thermal Shock on Rock Dynamic Elastic Properties and Permeability of Wolfcamp Core Samples – An Experimental Study

2021 ◽  
Author(s):  
Mahdi Ramezanian ◽  
Hossein Emadi
Keyword(s):  
Mechanical Properties ◽  
Thermal Shock ◽  
Elastic Properties ◽  
Cryogenic Treatment ◽  
Xrd Analysis ◽  
Rock Properties ◽  
Core Samples ◽  
Permeability Enhancement ◽  
Rock Mechanical Properties ◽  
Dynamic Elastic Properties

Abstract A few researches have been conducted to study effects of cryogenic treatment (known as thermal shocking) on unconventional rock properties, while they have been extensively studied in geothermal projects. The results show that cryogenic treatment significantly alters the rock mechanical properties by creation of new cracks owing to thermally induced stresses resulting in the permeability enhancement. In this laboratory study, effects of cryogenic treatment (thermal shocking) on permeability and dynamic elastic properties of three Wolfcamp core samples (one outcrop and two downhole samples) at downhole conditions were experimentally evaluated. Permeability and dynamic rock mechanical properties were measured before and after conducting each cycle of thermal shock. Using X-ray powder diffraction (XRD) analysis, the mineral compositions of the cores were determined. The results demonstrate that implementing the thermal shock technique on the core samples results in increasing their permeability and ductility.

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