Numerical simulation of complex fracture geometry caused by hydrodynamics in shale with pre-existing weak planes

2021 ◽  
Vol 199 ◽  
pp. 108306
Author(s):  
Yongquan Hu ◽  
Qiang Wang ◽  
Jinzhou Zhao ◽  
Shengnan Chen ◽  
Daiqiang Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fracture Geometry ◽  
Complex Fracture

Investigation of Production-Induced Stress Changes for Infill-Well Stimulation in Eagle Ford Shale

SPE Journal ◽  
2018 ◽  
Vol 23 (04) ◽  
pp. 1372-1388 ◽  
Author(s):  
Xuyang Guo ◽  
Kan Wu ◽  
John Killough
Keyword(s):  
Horizontal Wells ◽  
Eagle Ford Shale ◽  
Eagle Ford ◽  
Fracture Geometry ◽  
Complex Fracture ◽  
Study Results ◽  
Stress Changes ◽  
Sensitivity Studies ◽  
Stress States ◽  
The Impact

Summary Heterogeneous stress has a great effect on fracture propagation and perforation-cluster efficiency of infill wells. Principal-stress reorientation induced by depletion of parent wells has been investigated by previous numerical studies assuming uniform biwing fracture geometry along the horizontal wells. However, recent field diagnostics indicate that fractures along the horizontal wells are generally nonuniformly developed. In this study, we investigated the impact of depletion of parent wells with complex fracture geometry on stress states, and analyzed stimulation efficiency of infill wells by using an in-house reservoir geomechanical model for Eagle Ford Shale. The model fully couples multiphase flow and rock deformation in three dimensions based on the finite-element method, incorporating complex fracture geometry and heterogeneity. We used this model to accurately characterize pressure distribution and to update stress states through history matching production data of parent wells in Eagle Ford Shale. Depletion of parent wells with nonuniform fracture geometries, which has not been researched thoroughly in the literature, is incorporated in the study. Results show that magnitude and orientation of principal stresses are greatly altered by depletion, and the alteration is uneven because of nonuniform fracture geometries. Stress reversal monitored at the center of the infill location starts after 1 year of production, and it takes another 8 months to be totally reversed for 90°. We also performed sensitivity studies to examine effects of parameters on changes of magnitude and orientation of stress at the infill location, and found that effects of bottomhole pressure (BHP), differential stress (DS), and fracture geometry of parent wells are all significant, whereas effects of the reservoir elastic property are limited. Effects of production time of parent wells are also noticeable in all sensitivity studies. This work analyzes stress-state change induced by depletion of parent wells in Eagle Ford Shale, and provides critical insights into the optimization for stimulation of infill wells.

Can We Engineer Better Multistage Horizontal Completions? Evidence of the Importance of Near-wellbore Fracture Geometry from Theory, Lab and Field Experiments

2015 ◽  
Author(s):  
B.. Lecampion ◽  
J.. Desroches ◽  
X.. Weng ◽  
J.. Burghardt ◽  
J.E.. E. Brown
Keyword(s):  
Pressure Drop ◽  
Field Experiments ◽  
Horizontal Wells ◽  
Fracture Plane ◽  
Hydraulic Fractures ◽  
Multiple Fractures ◽  
Fracture Geometry ◽  
Complex Fracture ◽  
Limited Entry ◽  
The Impact

Abstract There is accepted evidence that multistage fracturing of horizontal wells in shale reservoirs results in significant production variation from perforation cluster to perforation cluster. Typically, between 30 and 40% of the clusters do not significantly contribute to production while the majority of the production comes from only 20 to 30% of the clusters. Based on numerical modeling, laboratory and field experiments, we investigate the process of simultaneously initiating and propagating several hydraulic fractures. In particular, we clarify the interplay between the impact of perforation friction and stress shadow on the stability of the propagation of multiple fractures. We show that a sufficiently large perforation pressure drop (limited entry) can counteract the stress interference between different growing fractures. We also discuss the robustness of the current design practices (cluster location, limited entry) in the presence of characterized stress heterogeneities. Laboratory experiments highlight the complexity of the fracture geometry in the near-wellbore region. Such complex fracture path results from local stress perturbations around the well and the perforations, as well as the rock fabric. The fracture complexity (i.e., the merging of multiple fractures and the reorientation towards the preferred far-field fracture plane) induces a strong nonlinear pressure drop on a scale of a few meters. Single entry field experiments in horizontal wells show that this near-wellbore effect is larger in magnitude than perforation friction and is highly variable between clusters, without being predictable. Through a combination of field measurements and modeling, we show that such variability results in a very heterogeneous slurry rate distribution; and therefore, proppant intake between clusters during a stage, even in the presence of limited entry techniques. We also note that the estimated distribution of proppant intake between clusters appears similar to published production log data. We conclude that understanding and accounting for the complex fracture geometry in the near-wellbore is an important missing link to better engineer horizontal well multistage completions.

Numerical Simulation for Shale Gas Flow in Complex Fracture System of Fractured Horizontal Well

2018 ◽  
Vol 19 (3-4) ◽  
pp. 367-377 ◽  
Author(s):  
Yingzhong Yuan ◽  
Wende Yan ◽  
Fengbo Chen ◽  
Jiqiang Li ◽  
Qianhua Xiao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Horizontal Well ◽  
Fracture Network ◽  
Gas Reservoir ◽  
Complex Fracture ◽  
Shale Gas Reservoir ◽  
Fracture Parameters ◽  
Fracture Systems ◽  
Fractured Horizontal Well

AbstractComplex fracture systems including natural fractures and hydraulic fractures exist in shale gas reservoir with fractured horizontal well development. The flow of shale gas is a multi-scale flow process from microscopic nanometer pores to macroscopic large fractures. Due to the complexity of seepage mechanism and fracture parameters, it is difficult to realize fine numerical simulation for fractured horizontal wells in shale gas reservoirs. Mechanisms of adsorption–desorption on the surface of shale pores, slippage and Knudsen diffusion in the nanometer pores, Darcy and non-Darcy seepage in the matrix block and fractures are considered comprehensively in this paper. Through fine description of the complex fracture systems after horizontal well fracturing in shale gas reservoir, the problems of conventional corner point grids which are inflexible, directional, difficult to geometrically discretize arbitrarily oriented fractures are overcome. Discrete fracture network model based on unstructured perpendicular bisection grids is built in the numerical simulation. The results indicate that the discrete fracture network model can accurately describe fracture parameters including length, azimuth and density, and that the influences of fracture parameters on development effect of fractured horizontal well can be finely simulated. Cumulative production rate of shale gas is positively related to fracture half-length, fracture segments and fracture conductivity. When total fracture length is constant, fracturing effect is better if single fracture half-length or penetration ratio is relatively large and fracturing segments are moderate. Research results provide theoretical support for optimal design of fractured horizontal well in shale gas reservoir.

Numerical Study of Proppant Transport in Complex Fracture Geometry

2016 ◽  
Author(s):  
Jiahang Han ◽  
Peng Yuan ◽  
Xu Huang ◽  
Hao Zhang ◽  
Andy Sookprasong ◽  
...  
Keyword(s):  
Numerical Study ◽  
Fracture Geometry ◽  
Proppant Transport ◽  
Complex Fracture

Complex Fracture Geometry Investigations Conducted on Western-Siberian Oilfields at Rosneft Company

2007 ◽  
Author(s):  
Aleksei Nikolaevich Nikitin ◽  
Alexander Shirnen ◽  
Jerome Maniere
Keyword(s):  
Fracture Geometry ◽  
Complex Fracture

Numerical study of complex fracture geometry effect on two-phase performance of shale-gas wells using the fast EDFM method

2018 ◽  
Vol 164 ◽  
pp. 603-622 ◽  
Author(s):  
Mohammad AlTwaijri ◽  
Zhaohui Xia ◽  
Wei Yu ◽  
Liangchao Qu ◽  
Yunpeng Hu ◽  
...  
Keyword(s):  
Shale Gas ◽  
Numerical Study ◽  
Gas Wells ◽  
Two Phase ◽  
Fracture Geometry ◽  
Geometry Effect ◽  
Complex Fracture
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