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Collaborating Authors
Reservoir Characterization
An Advanced, Integrated Simulator for Management of Produced Water Re-Injection in Multilayer Vertical or Horizontal Wells
Elkatatny, S.M. (Advantek International) | Farid, A. (Cairo University) | Mohamed, I. (Advantek International) | Abou-Sayed, O.A. (Advantek International) | Block, G.I. (Advantek International)
Abstract Produced water re-injection (PWRI) is often the safest and most economical method for disposal of produced water in the oil industry. Two key issues that affect the management of PWRI are the formation damage and the constrained pumping pressure at the wellhead. A simulator was developed to handle the design of single-zone or multi-zone water injection in multilayered reservoirs. The simulator can accommodate both vertical and horizontal wells operated under matrix and/or fractured regimes. It is also able to account for the impact of formation damage and user-defined wellhead pressure constraints. Results obtained from the simulator showed good agreement with known injection behaviors. For vertical wells, injection conformance depends on KH (permeability-thickness) and the minimum horizontal stress; in the case of multi-fractured horizontal wells, the outermost fractures (those near the tip and the heel of the horizontal well) are longer than the fractures in the middle. Lastly, by constraining the maximum allowable surface pressure, frictional pressure drops in both the wellbore and fracture cause the injection rate to decline, which in turn affects both the fracture geometry and the maximum disposal volumes.
- Europe (1.00)
- North America > United States > Texas (0.29)
- Africa > Middle East > Egypt (0.28)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.69)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- (3 more...)
Abstract According to the technical guide for grouting method for dam construction in Japan modified in the year 2003, one of the key issues for grouting is quality assurance and effectiveness by minimizing the amount of injected grout. Hence, the grouting management support system was newly developed by combining joint density diagram and geostatistical simulations. In this system, the joint density diagram was used to determine most effective direction for the grout injection boreholes and the hydraulic conductivity fields before/after grout injection were estimated by geostatistical simulations. In this paper, the newly developed system was introduced and applied to the actual underground structure construction site.
- Management (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (0.55)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (0.53)
Abstract High injection rates in water injectors leads to mobilization of particles in unconsolidated formations and creates preferential flow paths within the porous medium. Channelization in porous medium occurs when fluid-induced stresses become locally larger than a critical threshold (rock stress); grains are then dislodged and carried away, hence porosity and permeability of the medium will be altered along the induced flow paths. Additionally, rapid shut-ins result in pressure imbalance between the wellbore and formation. Flowback of the particles results in sand accumulation, and consequently loss of injectivity, which is a common problem in unconsolidated formations like the ones in deep water Gulf of Mexico. Experimental studies have confirmed the presence of dependent and independent flow patterns; however, there is no integrated model to describe flow patterns and predict probable issues for water injection at the reservoir scale. The objective of this study is to provide a model for a channel initiation/propagation during injection and flowback in injection wells. A finite volume model is developed based on multiphase fraction volume concept that decomposes porosity into mobile and immobile phases where these phases change spatially and evolve over time that leads to development of erosional channels in radial patterns depending on injection rates, viscosity, magnitude of in situ stresses and rock properties. The model accounts for both particle releasing and suspension deposition. The developed model explains injectivity change with injection rates observed in unconsolidated reservoirs.
- North America > United States > Texas (0.93)
- Europe (0.93)
- North America > United States > Colorado > Piceance Basin > Buzzard Field > Mesaverde Formation > Williams Fork Formation (0.99)
- North America > United States > Colorado > Piceance Basin > Buzzard Field > Mancos Formation > Williams Fork Formation (0.99)
- North America > United States > Colorado > Piceance Basin > Buzzard Field > Iles Formation > Williams Fork Formation (0.99)
- (3 more...)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
Abstract In recent years, the development of oil and gas from shale has proceeded quickly in the world due to the application of multi-stage fracturing technology in horizontal wells. It is imperative to study the poroelastic characteristics of the rock for modeling the performance of rock under in-situ conditions, thus ensuring the success of hydraulic fracturing. Biot's coefficient is one of the key poroelastic parameters for calculating the effective stress for creating artificial fractures in the shale formations. In this study, we propose anew method to measure the Biot's coefficient. Our method simplified the measuring procedures to obtain the Biot's coefficient by controlling the confining pressure, which isused to maintain the volume of the sample, while altering the pore pressure. Shales amples recovered form Bakken formation in Willistion Basin is tested using this method. The results of our experiments show that the Biot's coefficient of Bakken samples obtained from horizontal drilling and vertical drilling are significantly different from each other. This significant difference of Biot's coefficient with different drilling-direction provides scientists and engineers a solid base for in-situ stress analysis during multi stage hydraulic fracturing and reservoir depletion due to production.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.95)
- North America > United States > South Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > North Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > Montana > Williston Basin > Bakken Shale Formation (0.99)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
Abstract Four in-situ tests performed in salt caverns in France and Germany are described. The main objective of these tests was to increase our understanding of the long-term behavior of abandoned caverns. It is proven that, in the long term, when cavern brine has reached thermal equilibrium with the rock mass, pressure evolution is governed by cavern creep closure and brine micropermeation through the cavern walls. An equilibrium pressure is reached when the closure rate exactly equals the permeation rate. In the shallow caverns described in this paper, equilibrium pressure is significantly lower than geostatic pressure, ruling out any risk of fracture onset at the cavern roof. Interpretation of these tests allows salt permeability to be back-calculated.
- Europe (1.00)
- North America > United States > Texas (0.28)
- Well Drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (0.94)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (0.91)
Abstract Enhancing formation permeability through hydraulic fracturing (HF) has become a proven tool for hydrocarbon extraction in shale (i.e., a resource rock formation) as well as geothermal heat extraction from hot, dry rock reservoirs. Permeability in the nanodarcy range is possible in many such unconventional oil and gas reservoirs, thus requiring production to greatly depend on the existence of natural fractures and the additional surface area generated by hydraulic fracturing. Mapping and characterizing the structure of a hydraulic fracture network can be performed using acoustic emission analysis techniques. Many techniques exist to obtain an estimated stimulated reservoir volume (SRV), which is used as a correlation metric for expected well performance. Most of these techniques use the discrete acoustic emission events as boundary points and determine the volume of rock inside the three-dimensional cloud of data that was acquired. While some of these methods for determining rock volumes affected throughout the fracturing process are sophisticated, understanding of the cumulative fracture opening volume from acoustic emission data is not well understood. Laboratory hydraulic fracturing tests were performed while monitoring acoustic emissions continuously. Sample sizes were approximately 15×15×25 cm. Granite was used as the reservoir material due to the high brittleness, very low permeability, and relative homogeneity. Acoustic emission data recorded throughout the fracturing process was analyzed for three-dimensional event source locations, source mechanisms, orientations and directions of crack movement, and volumetric deformations. A cumulative volumetric deformation was calculated for a specific area near the openhole wellbore where fracture initiation occurred. This volumetric deformation was then compared to micron scale CT scan data for the same region. The fracturing pattern and the geometrical properties of fracturing (e.g., volume, fracture width, etc.) can be measured and analyzed from the 3D CT images. The resolution of the micro-CT images is sufficient to resolve most tiny fractures. By direct observation through micron CT imaging, the acoustic emission data is compared. The consistence of volumetric contributions of these two sets of data is investigated.
Abstract In this study, evolution of mechanical and hydraulic properties in Berea sandstone with initial porosity of 20 %: is examined quantitatively by replicating mineral trapping process within pore spaces. The artificially accelerated mineral trapping is achieved by injecting a grout, resulting in calcite precipitation. The amount of calcite precipitated can be controlled by changing the concentrations of the grout and the total injection volume. The preliminary experiments indicate that the change of the mechanical and hydraulic properties is significant even if the calcite amount is relatively small – the values of Young’s modulus/permeability increase/decrease with increase of the calcite amount. Specifically, the permeability decreases by one order of magnitude as the initial porosity of 20 % reduces to 18 %. This intense decrease of permeability may not be able to be replicated by existing numerical models, although distribution of the calcite precipitated within rock samples should be adequately examined because uniform distribution may not be achieved.
- North America > United States > West Virginia (0.26)
- North America > United States > Pennsylvania (0.26)
- North America > United States > Ohio (0.26)
- North America > United States > Kentucky (0.26)
- Geology > Mineral > Carbonate Mineral > Calcite (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.63)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (0.88)
Near-Well Integrity and Thermal Effects: A Computational Road from Laboratory to Field Scale
Lavrov, A. (SINTEF Petroleum Research) | Torsæter, M. (SINTEF Petroleum Research) | Albawi, A. (Norwegian University of Science and Technology) | Todorovic, J. (SINTEF Petroleum Research) | Opedal, N. (SINTEF Petroleum Research) | Cerasi, P. (SINTEF Petroleum Research)
Abstract Integrity of the near-well area is crucial for preventing leakage between geological horizons and towards the surface during CO2 storage, hydrocarbon production and well stimulation. The paper consists of two parts. In the first part, a finite-element model of earlier laboratory tests on thermal cycling of a casing/cement/rock assemblage is set up. It is demonstrated that radial tensile stresses contributing to annular cement debonding are likely to develop during cooling of such an assemblage. The results of the modeling are in agreement with the results of the earlier laboratory experiments, with regard to the temperature histories, CT data, and location of acoustic emission sources. In the second part of the paper, a computational procedure is developed for upscaling of data about rock damage obtained from CT, to a finite-element model of flow in porous media around a well. The damaged zone is shown to dominate the flow along the axis of a compound specimen (a hollow cylinder of sandstone filled with cement). Implications for leakage along an interface between cement and rock in-situ are discussed.
- Asia (0.93)
- North America > United States > Texas (0.68)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.36)
- Well Drilling > Casing and Cementing (1.00)
- Well Completion (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- (4 more...)
Abstract Multiple transverse hydraulic fractures are created simultaneously in each stage for economically viable production of hydrocarbons in shales. The spacing between fractures is an important component to consider when developing an optimum stimulation design. Another important aspect to consider, that is often overlooked, is the anisotropy of mechanical properties inherent in shales. This study aims to provide an insight into the controlling effects of fracture spacing and different levels of rock property anisotropy on the fracture aperture during simultaneous fracture initiation and propagation. Multiple fracture propagation is simulated using 3-Dimensional [3D] finite element models [FEM]. All simulations in this study include simultaneous propagation of four fractures in pre-defined planes using cohesive elements in a linear elastic medium. Numerous FEMs with varying spacing between fractures and varying levels of anisotropy are generated to analyze the effect of spacing and rock anisotropy on the fracture apertures of the edge fractures and center fractures. The multi-fracture propagation model used in this study is capable of showing the isolated influence of each parameter tested. The results show that there is a significant effect on the fracture widths of center and edge fractures across the entire range of fracture spacing considered in the study. The center fractures are more sensitive to changes in fracture spacing and changes in elastic moduli.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.94)
- North America > United States > West Virginia > Appalachian Basin > Marcellus Shale Formation (0.99)
- North America > United States > Virginia > Appalachian Basin > Marcellus Shale Formation (0.99)
- North America > United States > Pennsylvania > Appalachian Basin > Marcellus Shale Formation (0.99)
- (5 more...)
Abstract Tight formations or the reservoir rocks with extremely low permeability, make vast hydrocarbon fields in the United States and worldwide. In contrast to conventional reservoirs, production from tight formations is only economic when such formations are hydraulically fractured. Economic production from tight formations relies on the existence of a network of connecting fractures in the rock to create a more volumetric pattern of fracture. To achieve this goal, we have proposed a novel method for fracturing rock by thermal means, in which the rock is frozen prior to hydraulic fracturing, leading to a reduction of effective stress and creation of thermal cracks. The question is how much is the effective rock permeability improved by cooling down the hot reservoir. We use the discrete element method (DEM) to obtain a network of thermal fractures as the rock is frozen. The permeability can then be calculated using a pore network model which is not the subject of this paper. Here we present the Discrete Element Method (DEM) analysis for thermal fracturing and show the effect of main parameters involved in the solutions obtained from the DEM, including the stiffness of rock.
- Europe > Norway > Norwegian Sea (0.45)
- North America > United States > Texas (0.31)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.31)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)