气候变化领域集成服务门户(CCPortal): Numerical Modeling of Fracture Network Evolution in Organic-Rich Shale With Rapid Internal Fluid Generation

CCPortal

DOI	10.1029/2020JB019445
	Numerical Modeling of Fracture Network Evolution in Organic-Rich Shale With Rapid Internal Fluid Generation
	Rabbel O.; Mair K.; Galland O.; Grühser C.; Meier T.
发表日期	2020
ISSN	21699313
卷号	125 期号:7
英文摘要	When low-permeability and organic-rich rocks such as shale experience sufficient heating, chemical reactions including shale dehydration and maturation of organic matter lead to internal fluid generation. This may cause substantial pore fluid overpressure and fracturing. In the vicinity of igneous intrusions emplaced in organic-rich shales, temperatures of several hundred degrees accelerate these processes and lead to intense fracturing. The resulting fracture network provides hydraulic pathways, which allow fluid expulsion and affect hydrothermal fluid flow patterns. However, the evolution of these complex fracture networks and controls on geometry and connectivity are poorly understood. Here, we perform a numerical modeling study based on the extended finite element method to investigate coupled hydromechanical fracture network evolution due to fast internal fluid generation. We quantify the evolution of different initial fracture networks under varying external stresses by analyzing parameters including fracture length, opening, connectivity, and propagation angles. The results indicate a three-phase process including (1) individual growth, (2) interaction, and (3) expulsion phase. Magnitude of external stress anisotropy and degree of fracture alignment with the largest principal stress correlate with increased fracture opening. We additionally find that although the external stress field controls the overall fracture orientation distribution, local stress interactions may cause significant deviations of fracture paths and control the coalescence characteristics of fractures. Establishing high connectivity in cases with horizontally aligned initial fractures requires stress anisotropy with σV > σH, while the initial orientation distribution is critical for connectivity if stresses are nearly isotropic. ©2020. The Authors.
英文关键词	extended finite element method; fracture network evolution; maturation around igneous intrusions; shale
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187777
作者单位	Physics of Geological Processes, The NJORD Centre, Department of Geosciences, University of Oslo, Oslo, Norway; geomecon GmbH, Berlin, Germany
推荐引用方式 GB/T 7714	Rabbel O.,Mair K.,Galland O.,et al. Numerical Modeling of Fracture Network Evolution in Organic-Rich Shale With Rapid Internal Fluid Generation[J],2020,125(7).
APA	Rabbel O.,Mair K.,Galland O.,Grühser C.,&Meier T..(2020).Numerical Modeling of Fracture Network Evolution in Organic-Rich Shale With Rapid Internal Fluid Generation.Journal of Geophysical Research: Solid Earth,125(7).
MLA	Rabbel O.,et al."Numerical Modeling of Fracture Network Evolution in Organic-Rich Shale With Rapid Internal Fluid Generation".Journal of Geophysical Research: Solid Earth 125.7(2020).