Modeling simultaneous growth of multiple hydraulic fractures and their interaction with natural fractures

2009 ◽  
Author(s):  
Jon Edward Olson ◽  
Arash Dahi Taleghani
Keyword(s):  
Hydraulic Fractures ◽  
Natural Fractures ◽  
Simultaneous Growth

scholarly journals Interaction between hydraulic fractures and natural fractures: current status and prospective directions

2019 ◽  
Vol 10 (4) ◽  
pp. 1613-1634 ◽  
Author(s):  
Oladoyin Kolawole ◽  
Ion Ispas
Keyword(s):  
Oil And Gas ◽  
Petroleum Industry ◽  
Gas Production ◽  
Current Status ◽  
Complex Nature ◽  
Hydraulic Fractures ◽  
Natural Fractures ◽  
Oil And Gas Production ◽  
The Past ◽  
Unconventional Oil And Gas

Abstract Hydraulic fracturing treatment is one of the most efficient conventional matrix stimulation techniques currently utilized in the petroleum industry. However, due to the spatiotemporal complex nature of fracture propagation in a naturally- and often times systematically fractured media, the influence of natural fractures (NF) and in situ stresses on hydraulic fracture (HF) initiation and propagation within a reservoir during the hydrofracturing process remains an important issue. Over the past 50 years of advances in the understanding of HF–NF interactions, no comprehensive revision of the state of the knowledge exists. Here, we reviewed over 140 scientific articles on investigations of HF–NF interactions, published over the past 50 years. We highlight the most commonly observed HF–NF interactions and their implications for unconventional oil and gas production. Using observational and quantitative analyses, we find that numerical modeling and simulation is the most prominent method of approach, whereas there are less publications on the experimental approach, and analytical method is the least utilized approach. Further, we suggest how HF–NF interactions can be monitored in real time on the field during a pre-frac test. Lastly, based on the results of our literature review, we recommend promising areas of investigation that may provide more profound insights into HF–NF interactions in such a way that can be directly applied to the optimization of fracture-stimulation field operations.

scholarly journals Analysis of hydraulic fracture behavior and well pattern optimization in anisotropic coal reservoirs

2020 ◽  
pp. 014459872096083
Author(s):  
Yulong Liu ◽  
Dazhen Tang ◽  
Hao Xu ◽  
Wei Hou ◽  
Xia Yan
Keyword(s):  
Hydraulic Fracture ◽  
Coalbed Methane ◽  
Fracture Network ◽  
Simulation Software ◽  
Natural Fracture ◽  
Hydraulic Fractures ◽  
Natural Fractures ◽  
Well Pattern ◽  
Well Pattern Optimization ◽  
The Impact

Macrolithotypes control the pore-fracture distribution heterogeneity in coal, which impacts stimulation via hydrofracturing and coalbed methane (CBM) production in the reservoir. Here, the hydraulic fracture was evaluated using the microseismic signal behavior for each macrolithotype with microfracture imaging technology, and the impact of the macrolithotype on hydraulic fracture initiation and propagation was investigated systematically. The result showed that the propagation types of hydraulic fractures are controlled by the macrolithotype. Due to the well-developed natural fracture network, the fracture in the bright coal is more likely to form the “complex fracture network”, and the “simple” case often happens in the dull coal. The hydraulic fracture differences are likely to impact the permeability pathways and the well productivity appears to vary when developing different coal macrolithtypes. Thus, considering the difference of hydraulic fracture and permeability, the CBM productivity characteristics controlled by coal petrology were simulated by numerical simulation software, and the rationality of well pattern optimization factors for each coal macrolithotype was demonstrated. The results showed the square well pattern is more suitable for dull coal and semi-dull coal with undeveloped natural fractures, while diamond and rectangular well pattern is more suitable for semi-bright coal and bright coal with more developed natural fractures and more complex fracturing fracture network; the optimum wells spacing of bright coal and semi-bright coal is 300 m and 250 m, while that of semi-dull coal and dull coal is just 200 m.

scholarly journals Hydraulic-Fracture-Height Growth Under the Combined Influence of Stress Barriers and Natural Fractures

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 302-318 ◽  
Author(s):  
Jixiang Huang ◽  
Joseph P. Morris ◽  
Pengcheng Fu ◽  
Randolph R. Settgast ◽  
Christopher S. Sherman ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Fluid Pressure ◽  
Height Growth ◽  
Two Dimensions ◽  
Natural Fracture ◽  
Hydraulic Fractures ◽  
Natural Fractures ◽  
3D Interaction ◽  
Fracture Height ◽  
Fully Coupled

Summary A fully coupled finite-element/finite-volume code is used to model 3D hydraulically driven fractures under the influence of strong vertical variations in closure stress interacting with natural fractures. Previously unknown 3D interaction mechanisms on fracture-height growth are revealed. Slipping of a natural fracture, triggered by elevated fluid pressure from an intersecting hydraulic fracture, can induce both increases and decreases of normal stress in the minimum-horizontal-stress direction, toward the center and tip of the natural fracture, respectively. Consequently, natural fractures are expected to be able to both encourage and inhibit the progress of hydraulic fractures propagating through stress barriers, depending on the relative locations between the intersecting fractures. Once the hydraulic fracture propagates above the stress barrier through the weakened segment near a favorably located natural fracture, a configuration consisting of two opposing fractures cuts the stress barrier from above and below. The fluid pressure required to break the stress barrier under such opposing-fracture configurations is substantially lower than that required by a fracture penetrating the same barrier from one side. Sensitivity studies of geologic conditions and operational parameters have also been performed to explore the feasibility of controlled fracture height. The interactions between hydraulic fractures, natural fractures, and geologic factors such as stress barriers in three dimensions are shown to be much more complex than in two dimensions. Although it is impossible to exhaust all the possible configurations, the ability of a 3D, fully coupled numerical model to naturally capture these processes is well-demonstrated.

Impact of the stress state and the natural network of fractures/faults on the efficiency of hydraulic fracturing operations in the Goldwyer Shale Formation

2020 ◽  
Vol 60 (1) ◽  
pp. 163
Author(s):  
Partha Pratim Mandal ◽  
Reza Rezaee ◽  
Joel Sarout
Keyword(s):  
Stress State ◽  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Cost Effective ◽  
Fracture Network ◽  
Fault Reactivation ◽  
Hydraulic Fractures ◽  
Natural Fractures ◽  
Future Production ◽  
Shale Formation

Cost-effective hydrocarbon production from low-permeability unconventional reservoirs requires multi-stage hydraulic fracturing (HF) operations. Each HF stage aims to generate the most spatially extended fracture network, giving access to the largest volume of reservoir possible (stimulated volume) and allowing hydrocarbons to flow towards the wellbore. The size of the stimulated volume, and therefore, the efficiency of any given HF stage, is governed by the rock’s deformational behaviour and presence of pre-existing natural fractures/faults. Naturally elevated pore pressures at depth not only help to reduce the injection energy required to generate hydraulic fractures but can also induce slip along pre-existing fractures/faults, and therefore, enhance production rates. Here we analyse borehole image, density, resistivity and sonic logs available from a vertical exploration well in the Goldwyer Shale Formation (Canning Basin) to (i) characterise the pre-existing network of natural fractures; and (ii) estimate the in-situ pore pressure and stress state at depth. The aim of such an analysis is to evaluate the possibility of fracture/fault reactivation (slip) during and following HF operations. Based on this analysis, we found that an increase in the formation's pore pressure by only a few MPa (typically ~5–10 MPa) could lead to slip along pre-existing fractures/faults, provided they are favourably oriented with respect to the prevalent stress field for future production. We also found that slip along the horizontal or sub-horizontal bedding of the Goldwyer Formation is unlikely in view of the prevalent strike-slip faulting regime, unless an extremely large overpressure exists within the reservoir.

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