scholarly journals Effect of Diagenesis on Geomechanical Properties of Organic‐rich Calcareous Shale: A Multiscale Investigation

2021 ◽  
Author(s):  
T. S. Charlton ◽  
M. Goodarzi ◽  
M. Rouainia ◽  
A. C. Aplin ◽  
P. Cubillas
Keyword(s):  
Geomechanical Properties ◽  
Calcareous Shale

scholarly journals Sub-Level Stoping in an Underground Limestone Quarry: An Analysis of the State of Stress in an Evolutionary Scenario

2016 ◽  
Vol 61 (1) ◽  
pp. 199-216 ◽  
Author(s):  
Marilena Cardu ◽  
Sergio Dipietromaria ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Models ◽  
The State ◽  
In Situ Tests ◽  
Future Scenario ◽  
Limestone Quarry ◽  
Geomechanical Properties ◽  
State Of Stress ◽  
Upper Level ◽  
Pillar Structure

Abstract The aim of this study was to evaluate the state of stress of a „voids-pillar“ structure excavated by means of the sub-level stoping method in an underground limestone quarry near Bergamo (Italy). Both the current structure of the quarry (i.e. the rooms exploited till now) and a possible future scenario were analysed using the (FDM) FLAC 2D code. The quarry has been in operation since 1927; at present, exploitation is carried out underground via the sub-level stoping method. Exploitation involves two levels, with 5 rooms on the upper level and 9 rooms on the lower level. After analysing data obtained from laboratory and in situ tests carried out on rock samples and natural discontinuities, the geomechanical properties of the medium, knowledge of which is essential in order to establish the parameters that must be included in the numerical model, were evaluated. The implementation of three numerical models made it possible to study both the present conditions of quarry exploitation and the evolution of the exploited rooms, as well as a possible expansion involving a third level of rooms. Using the results obtained regarding the stress-strain present in the pillars, a potential change in room geometry was proposed aimed at reducing the stress state inside the pillars, decreasing plasticity and increasing overall quarry safety.

Joint Application of Diagenetic, Petrophysical and Geomechanical Data for Selecting Hydraulic Fracturing Candidate Zone

2021 ◽  
Vol 8 ◽  
pp. 55-79
Author(s):  
E. Bakhshi ◽  
A. Shahrabadi ◽  
N. Golsanami ◽  
Sh. Seyedsajadi ◽  
X. Liu ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Earth Model ◽  
Reservoir Properties ◽  
Stress Regime ◽  
Geomechanical Properties ◽  
Hydrocarbon Reservoir ◽  
Diagenetic Processes ◽  
Mechanical Earth Model ◽  
New Equation

The more comprehensive information on the reservoir properties will help to better plan drilling and design production. Herein, diagenetic processes and geomechanical properties are notable parameters that determine reservoir quality. Recognizing the geomechanical properties of the reservoir as well as building a mechanical earth model play a strong role in the hydrocarbon reservoir life cycle and are key factors in analyzing wellbore instability, drilling operation optimization, and hydraulic fracturing designing operation. Therefore, the present study focuses on selecting the candidate zone for hydraulic fracturing through a novel approach that simultaneously considers the diagenetic, petrophysical, and geomechanical properties. The diagenetic processes were analyzed to determine the porosity types in the reservoir. After that, based on the laboratory test results for estimating reservoir petrophysical parameters, the zones with suitable reservoir properties were selected. Moreover, based on the reservoir geomechanical parameters and the constructed mechanical earth model, the best zones were selected for hydraulic fracturing operation in one of the Iranian fractured carbonate reservoirs. Finally, a new empirical equation for estimating pore pressure in nine zones of the studied well was developed. This equation provides a more precise estimation of stress profiles and thus leads to more accurate decision-making for candidate zone selection. Based on the results, vuggy porosity was the best porosity type, and zones C2, E2 and G2, having suitable values of porosity, permeability, and water saturation, showed good reservoir properties. Therefore, zone E2 and G2 were chosen as the candidate for hydraulic fracturing simulation based on their E (Young’s modulus) and ν (Poisson’s ratio) values. Based on the mechanical earth model and changes in the acoustic data versus depth, a new equation is introduced for calculating the pore pressure in the studied reservoir. According to the new equation, the dominant stress regime in the whole well, especially in the candidate zones, is SigHmax>SigV>Sighmin, while according to the pore pressure equation presented in the literature, the dominant stress regime in the studied well turns out to be SigHmax>Sighmin>SigV.  

Characterization of Unconventional Reservoir for Development and Production: An Integrated Approach

2015 ◽  
Author(s):  
Omprakash Pal ◽  
Bilal Zoghbi ◽  
Waseem Abdul Razzaq
Keyword(s):  
Middle East ◽  
Integrated Approach ◽  
Advanced Technology ◽  
Additional Parameter ◽  
Unconventional Reservoir ◽  
Reservoir Properties ◽  
Capillary Suction ◽  
Geomechanical Properties ◽  
Oil Companies ◽  
Geochemical Properties

Abstract Unconventional reservoir exploration and development activities in the Middle East have increased and are expected to continue to do so. National oil companies in the Middle East have a strategy for maximizing oil exports as well as use of natural gas. This has placed emphasis on use of advanced technology to extend the lives of conventional reservoirs and more activities in terms of “unconventional gas and oil.” Understanding unconventional environments, such as shale reservoirs, requires unique processes and technologies based on reservoir properties for optimum reservoir production and well life. The objective of this study is to provide the systematic work flow to characterize unconventional reservoir formation. This paper discusses detailed laboratory testing to determine geochemical, rock mechanical, and formation fluid properties for reservoir development. Each test is described in addition to its importance to the reservoir study. Geochemical properties, such as total organic carbon (TOC) content to evaluate potential candidates for hydrocarbon, mineralogy to determine the formation type and clay content, and kerogen typing for reservoir maturity. Formation fluid sensitivity, such as acid solubility testing of the formation, capillary suction time testing, and Brinell hardness testing, are characterized to better understand the interaction of various fluids with the formation to help optimize well development. An additional parameter in unconventional reservoirs is to plan ahead when implementing the proper fracturing stimulation technique and treatment design, which requires determining the geomechanical properties of the reservoir as well as the fluid to be used for stimulation. Properties of each reservoir are unique and require unique approaches to design and conduct fracturing solutions. The importance of geomechanical properties is discussed here. This paper can be used to help operators obtain a broad overview of the reservoir to determine the best completion and stimulation approaches for unconventional development.

Embedding compaction processes in long-term evolution modeling of tidal marshes

2021 ◽  
Author(s):  
Riccardo Xotta ◽  
Claudia Zoccarato ◽  
Philip S. J. Minderhoud ◽  
Pietro Teatini
Keyword(s):  
Numerical Model ◽  
Marsh Surface ◽  
Long Term Evolution ◽  
Sediment Supply ◽  
Tidal Marshes ◽  
High Porosity ◽  
Fe Method ◽  
Geomechanical Properties ◽  
Term Evolution

<p>Tidal marshes are vulnerable and dynamic ecosystems with essential roles from protection against marine storms to biodiversity preservation. However, the survival of these environments is threatened by external stressors such as increasing mean sea level, reduction in sediment supply, and erosion. Tidal marshes are formed by deposition over the last centuries to millennia of sediments transported by surface water and biodegradation of organic matter derived from halophytic vegetation. Therefore, the sediment at the surface is characterized by high porosity and their large consolidation potential plays an important role in the future elevation dynamics, which is often not fully recognized.</p><p>Here we propose a novel three-dimensional numerical model to simulate the long-term dynamics of tidal marshes. A 3D groundwater flow equation in saturated conditions is implemented to compute the over-pressure dissipation with the aid of the finite element (FE) method, whereas the sediment consolidation is computed according to Terzaghi's theory.</p><p>A Lagrangian approach is implemented in the FE numerical model to properly consider the large soil deformation arising from the deposition of highly compressible material. The hydro-geomechanical properties, that depend on the intergranular effective stress, are highly non-linear.</p><p>The model takes advantage of a dynamic mesh that simulates the evolution of the landform elevation by means of an accretion/compaction mechanism: the elements deform in time as the soil consolidates and increase in number as the new sediments deposit over the marsh surface. The deposition is treated as input to the consolidation model and can vary in space and time.</p><p>The model is applied to simulate the long-term evolution of realistic tidal marshes in terms of accretion and consolidation due to the coupled dynamics of surficial and subsurface processes.</p>

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