Previous Talks

 

Wednesday December 14th, 2011

Complex hydraulic fracture propagation in naturally fractured shale gas reservoirs and impact of natural fractures on stimulation

Xiaowei Weng, Schlumberger

Abstract

Hydraulic fracturing in shale gas reservoirs has often resulted in complex fracture network growth, as evidenced by microseismic monitoring. The nature and degree of fracture complexity are strongly dependent upon the pre-existing natural fractures in the formation and in-situ stress conditions. Most of the existing commercial hydraulic fracture design models in the industry are still limited to simulating only a single planar fracture. Only a limited number of models are available for simulating fracture network growth with drastically simplified network structure which have no direct correlation to the existing natural fracture structure.

A new hydraulic fracture model (called Unconventional Fracture Model, or UFM) has been developed recently to simulate complex fracture network propagation in a formation with pre-existing natural fractures, and has been implemented in a Petrel plug-in called Mangrove to support fracturing design in shale gas. The model solves a system of equations governing fracture deformation, height growth, fluid flow, and proppant transport in a complex fracture network with multiple propagating fracture tips. The interaction between a hydraulic fracture and pre-existing natural fractures is taken into account by using an analytical crossing model which is validated against the experimental data. This talk gives an overview of the UFM model and shows examples of the impact of natural fracture characterization on the hydraulic fracture geometry.

Speaker Biography

Xiaowei Weng is Project Manager for Modeling and Mechanics in EMS Pressure Pumping and Chemistry Group, based in Sugar Land, Texas. He received his MS and PhD degrees in Engineering Mechanics from the University of Texas at Austin. He has 21 years of industry experience, including 9 years with ARCO Exploration and Production Technology, and 12 years with Schlumberger. His work involved the modeling of hydraulic fracture, acid fracturing, multi-fractured horizontal well completion and production, wellbore hydraulics, coiled tubing cleanout, and CT downhole measurements interpretation. He has published over 20 papers on hydraulic fracturing and CT cleanout.

References

The following references cover much of the material presented in the talk, and may be useful for those wanting to start reading about hydraulic fracture propagation in naturally fractured shale gas reservoirs:

Hydraulic Fracture Crossing Natural Fracture at Non-Orthogonal Angles, A Criterion, Its Validation and Applications, SPE 139984 by H. Gu, X. Weng, J. Lund, M. Mack, U. Ganguly, and R. Suarez-Rivera, presented at the SPE Hydraulic Fracturing Technology Conference, 24-26 January 2011, The Woodlands, Texas, USA.

Integrating Microseismic Mapping and Complex Fracture Modeling to Characterize Hydraulic Fracture Complexity, SPE 140185 by C. Cipolla, X. Weng, M. Mack, U. Ganguly, H. Gu, O. Kresse, and C. Cohen, presented at the SPE Hydraulic Fracturing Technology Conference, 24-26 January 2011, The Woodlands, Texas, USA.

Modeling of Hydraulic Fracture Network Propagation in a Naturally Fractured Formation, SPE 140253 by X. Weng, O. Kresse, C. Cohen, R. Wu, and H. Gu, presented at the SPE Hydraulic Fracturing Technology Conference, 24-26 January 2011, The Woodlands, Texas, USA.