--> ABSTRACT: The Use of Seismic Emission Tomography (SET) for the Direct Mapping of Natural or Hydraulic Stimulation Induced Fracture Networks and Their Impact to the Natural Permeability Field, by Geiser, Peter; Vermilye, Jan; Roundtree, Russell; Lacazette, Alfred; Thompson, Laird; Hellman, Sid; Dricker, Ilya; #90135 (2011)

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The Use of Seismic Emission Tomography (SET) for the Direct Mapping of Natural or Hydraulic Stimulation Induced Fracture Networks and Their Impact to the Natural Permeability Field

Geiser, Peter 1; Vermilye, Jan 1; Roundtree, Russell 1; Lacazette, Alfred 2; Thompson, Laird 3; Hellman, Sid 4; Dricker, Ilya 4
(1)Global Microseismic Services, Inc., Denver, CO. (2) EQT Production, Pittsburgh, PA. (3) UF3, Utah State, Logan, UT. (4) ISTI, Saratoga Springs, NY.

SET is a new tool for imaging micro-seismic emissions using surface or buried grid arrays. Skeletonization technology can be utilized to extract the topology of the natural and induced fracture system and predict fluctuations in the intrinsic permeability at both the well and field scale. A study testing the technology was conducted in vertically stacked horizontal wells in a shale gas reservoir in the eastern US. The study’s goal was to monitor a series of nitrogen frac job and to attempt to image the frac and the natural fault and fracture fairways that are the main producing features in the reservoir. An extensive array of independent data sets was collected including: field-wide pressure monitoring, interference testing, chemical and radioactive frac tracers, borehole images, conventional and mechanical properties logs, continuous quadrupole mass-spectrometer drilling-gas logs, and pre and post-frac production logs. These data sets were used in conjunction with maps of the fracture fairways and frac induced “rubbilization” created by the “skeletonization” techniques to map and simulate the reservoir production system in 3D. Fracture intersections in the well bore were mapped with both conventional images (electrical and acoustic) and optical televiewer logs. We find that “skeletons” derived from SET at a single mult-well pad provide valuable maps of the fracture permeability at field-scale, give significant new insights into reservoir performance and guide field development drilling. At a finer scale, the results provide insight into the fracing process itself, including frac initiation and near-wellbore frac propagation. The study provides further confirmation that fracture maps produced by “skeletonizing” SET data are a powerful new tool for optimizing complex reservoirs and characterizing naturally fractured reservoirs.

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.