The classification and the evaluation for stimulated reservoir volume (SRV) estimation models using microseismic events based on three typical grid structures

2022 ◽  
pp. 110169
Author(s):  
Xing Liu ◽  
Yan Jin ◽  
Botao Lin
Keyword(s):  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Microseismic Events ◽  
Estimation Models

scholarly journals Induced Seismicity and Detailed Fracture Mapping as Tools for Evaluating HDR Reservoir Volume

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2593
Author(s):  
Elżbieta Węglińska ◽  
Andrzej Leśniak
Keyword(s):  
Induced Seismicity ◽  
Fracture Network ◽  
Flowing Fluid ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Cluster Evolution ◽  
Microseismic Events ◽  
Fracture Mapping ◽  
Mass Volume ◽  
Stimulation Of

The main goal of this paper was to estimate the heat exchange rock mass volume of a hot dry rock (HDR) geothermal reservoir based on microseismicity location. There are two types of recorded microseismicity: induced by flowing fluid (wet microseismicity) and induced by stress mechanisms (dry microseismicity). In this paper, an attempt was made to extract events associated with the injected fluid flow. The authors rejected dry microseismic events with no hydraulic connection with the stimulated fracture network so as to avoid overestimating the reservoir volume. The proposed algorithm, which includes the collapsing method, automatic cluster detection, and spatiotemporal cluster evolution from the injection well, was applied to the microseismic dataset recorded during stimulation of the Soultz-sous-Forets HDR field in September 1993. The stimulated reservoir volume obtained from wet seismicity using convex hulls is approximately five times smaller than the volume obtained from the primary cloud of located events.

Estimation of effective anisotropy simultaneously with locations of microseismic events

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. WC143-WC155 ◽  
Author(s):  
Vladimir Grechka ◽  
Paritosh Singh ◽  
Indrajit Das
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Time Lapse ◽  
Velocity Model ◽  
Convincing Evidence ◽  
Hydraulic Stimulation ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Industry Applications ◽  
Microseismic Events

Passive seismic tomography, in which the event locations and the velocity model are inferred simultaneously, is seldom used to process microseismic surveys acquired in the oil and gas industry. We discuss advantages of applying tomographic ideas to typical microseismic data recorded in a single, nearly vertical well to monitor hydraulic stimulation of a shale-gas reservoir. Microseismic events are conventionally located in the energy-industry applications using a velocity model derived from sonic logs and perforation shots. Instead of fixing the model, as is normally done, we alter it while locating the events. This added flexibility not only makes it possible to accurately predict traveltimes of the recorded P- and S-waves, but also provides a convincing evidence for anisotropy of the examined shale formation. While we find that velocity heterogeneity does not need to be introduced to explain the data acquired at each stage of hydraulic fracturing, the obtained models are suggestive of possible time-lapse changes in the anisotropy parameters that characterize the stimulated reservoir volume.

Stimulated-Rock Characteristics and Behavior in Multistage Hydraulic-Fracturing Treatment

SPE Journal ◽  
2015 ◽  
Vol 20 (04) ◽  
pp. 784-789 ◽  
Author(s):  
Avi Lin ◽  
Jianfu Ma
Keyword(s):  
Hydraulic Fracturing ◽  
3D Visualization ◽  
Stimulated Reservoir Volume ◽  
Multistage Hydraulic Fracturing ◽  
Reservoir Volume ◽  
Advanced Phase ◽  
Fracturing Process ◽  
Microseismic Events ◽  
3D Volume ◽  
Multiple Stages

Summary This paper presents a mathematical integration process through which all the important useful information and data related to stimulated rock are properly extracted and embedded so that the total effects of the hydraulic-fracturing stimulation are properly presented by the microseismic data detected and collected during the hydraulic-fracturing process. A multistage hydraulic-fracturing strategy is often used to help maximize the stimulated reservoir volume (SRV). The current analysis is based on chaining the stage results one-by-one. At each stage, the 3D SRV is constructed on the basis of its observed microseismic events with an enhanced convex-hull approach. This algorithm offers both a mathematical approximation of 3D volume and a 3D visualization of the SRV geophysical shape(s). More-detailed geometric characteristics are calculated further from the ellipsoid that best fits the constructed SRV, which relies on the acquired microseismic events. The characteristics include length, width, height, and orientation azimuth of the stimulated rock. Moreover, it forms the basis for calculating the overall SRV with the stage-by-stage approach. In the advanced phase, this algorithm offers characteristics related to the interaction between multiple stages. The accurate 3D geophysical geometry of the overlapping volume between multiple stages is extracted and is calculated, and the percentage of overlapping volume over the SRV is estimated at each stage. These volume-overlapping quantities reveal the potential communication between these stages, indicating the efficiency of hydraulic-fracturing efforts and implying the loss of treatment fluid. This algorithm provides the field engineers with several useful aspects: an essential, reliable, and direct compound tool to dynamically visualize the stimulated reservoir geometry and treatment-field evolution; a real-time evaluation of the efficiency of a hydraulic-fracturing treatment; and parameters to help increase the production of a stimulated reservoir.

scholarly journals A numerical investigation on the performance of hydraulic fracturing in naturally fractured gas reservoirs based on stimulated rock volume

2020 ◽  
Vol 10 (8) ◽  
pp. 3333-3345
Author(s):  
Ali Al-Rubaie ◽  
Hisham Khaled Ben Mahmud
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Natural Fracture ◽  
Shear Stresses ◽  
Individual Element ◽  
Natural Fractures ◽  
Gas Reservoirs ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Naturally Fractured

Abstract All reservoirs are fractured to some degree. Depending on the density, dimension, orientation and the cementation of natural fractures and the location where the hydraulic fracturing is done, preexisting natural fractures can impact hydraulic fracture propagation and the associated flow capacity. Understanding the interactions between hydraulic fracture and natural fractures is crucial in estimating fracture complexity, stimulated reservoir volume, drained reservoir volume and completion efficiency. However, because of the presence of natural fractures with diffuse penetration and different orientations, the operation is complicated in naturally fractured gas reservoirs. For this purpose, two numerical methods are proposed for simulating the hydraulic fracture in a naturally fractured gas reservoir. However, what hydraulic fracture looks like in the subsurface, especially in unconventional reservoirs, remain elusive, and many times, field observations contradict our common beliefs. In this study, the hydraulic fracture model is considered in terms of the state of tensions, on the interaction between the hydraulic fracture and the natural fracture (45°), and the effect of length and height of hydraulic fracture developed and how to distribute induced stress around the well. In order to determine the direction in which the hydraulic fracture is formed strikethrough, the finite difference method and the individual element for numerical solution are used and simulated. The results indicate that the optimum hydraulic fracture time was when the hydraulic fracture is able to connect natural fractures with large streams and connected to the well, and there is a fundamental difference between the tensile and shear opening. The analysis indicates that the growing hydraulic fracture, the tensile and shear stresses applied to the natural fracture.

Analyzing the Impacts of Meshing and Grid Alignment in Dual-Porosity Dual-Permeability Upscaling

2021 ◽  
pp. 1-20
Author(s):  
Ziming Xu ◽  
Juliana Y. Leung
Keyword(s):  
Fracture Network ◽  
Fracture Plane ◽  
Fracture Density ◽  
Shape Factors ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Multiple Length Scales ◽  
Fracture Intensity ◽  
Cumulative Production ◽  
The Difference

Summary The discrete fracture network (DFN) model is widely used to simulate and represent the complex fractures occurring over multiple length scales. However, computational constraints often necessitate that these DFN models be upscaled into a dual-porositydual-permeability (DPDK) model and discretized over a corner-point grid system, which is still commonly implemented in many commercial simulation packages. Many analytical upscaling techniques are applicable, provided that the fracture density is high, but this condition generally does not hold in most unconventional reservoir settings. A particular undesirable outcome is that connectivity between neighboring fracture cells could be erroneously removed if the fracture plane connecting the two cells is not aligned along the meshing direction. In this work, we propose a novel scheme to detect such misalignments and to adjust the DPDK fracture parameters locally, such that the proper fracture connectivity can be restored. A search subroutine is implemented to identify any diagonally adjacent cells of which the connectivity has been erroneously removed during the upscaling step. A correction scheme is implemented to facilitate a local adjustment to the shape factors in the vicinity of these two cells while ensuring the local fracture intensity remains unaffected. The results are assessed in terms of the stimulated reservoir volume calculations, and the sensitivity to fracture intensity is analyzed. The method is tested on a set of tight oil models constructed based on the Bakken Formation. Simulation results of the corrected, upscaled models are closer to those of DFN simulations. There is a noticeable improvement in the production after restoring the connectivity between those previously disconnected cells. The difference is most significant in cases with medium DFN density, where more fracture cells become disconnected after upscaling (this is also when most analytical upscaling techniques are no longer valid); in some 2D cases, up to a 22% difference in cumulative production is recorded. Ignoring the impacts of mesh discretization could result in an unintended reduction in the simulated fracture connectivity and a considerable underestimation of the cumulative production.

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