A Validation Assessment of Microseismic Monitoring

Abstract

Microseismic monitoring of hydraulic fracturing in unconventional reservoirs is a valuable tool for delineating the effectiveness of stimulations, completions, and overall field development. Important information, such as fracture azimuth, fracture length, height growth, staging effectiveness, and many other geometric parameters, can typically be determined from good quality data sets. In addition, there are parameters now being extracted from microseismic data sets, or correlated with microseismic data, to infer other properties of the stimulation/completion system, such as stimulated reservoir volume (SRV), discrete fracture networks (DFNs), structural effects, proppant placement, permeability, fracture opening and closure, geohazards, and others. Much of the information obtained in this way is based on solid geomechanical or seismological principles, but some of it is speculative as well.This paper reviews published data where microseismic results have been validated by experiments using some type of ground-truth or alternative measurement procedure, discusses the geomechanics and seismological mechanisms that can be reasonably considered in evaluating the likelihood of inferring given properties, and appraises the uncertainties associated with monitoring and the effect on any inferences about fracture behavior. Considerable data now exist from tiltmeters, fiber-optic sensing, tracers, pressure sensors, multi-well-pad experiments, and production interference that can be used to aid the validation assessment.Relatively limited microseismic results have actually been validated in any consistent manner. Fracture azimuth from microseismic has been verified across a wide range of reservoir types using multiple techniques. Good validation of fracture length and height were performed in sandstones for planar fractures; fracture length and height in typical horizontal completions with multiple fractures or complexity have a lesser degree of verification. Other parameters, such as complexity, discrete fracture networks, source parameters, and SRV, have little supporting evidence to provide validation, even though they might have sound physical principles underlying their application. It is clear that microseismic monitoring would benefit from more attention to validation testing. In many cases, the data might be available but have not been used for validation purposes, or such results have not been published.

Optimization and Quality Assessment of Arrival Time Picking for Downhole Microseismic Events

“…Microseismic monitoring technology captures and analyzes detectable elastic waves generated by rock ruptures and has been widely used in the hydraulic fracture stimulation of unconventional reservoirs [1][2][3] and rock/mining engineering [4,5]. Arrival-time picking is a crucial step in microseismic data processing, and the picking result is useful for phase identification, hypocenter localization, mechanism analysis, and facture interpretation [6].…”

Recent comprehensive review for extended finite element method (XFEM) based on hydraulic fracturing models for unconventional hydrocarbon reservoirs

“…Microseismic monitoring is a passive measurement of microseismic event and provides crucial information such as magnitude, location and time of the event (Maulianda 2016). It is proven to be useful in showing the fracture geometries such as fracture length, fracture height, fracture width and fracture azimuth with high confidence (Warpinski and Wolhart 2016). Other application of microseismic monitoring in hydraulic fracturing includes observation of activated natural faults and faults, permeability (Shapiro et al 1997), and fracturing characterization using Moment Tensor Inversion (MTI) (Nolen-Hoeksema and Ruff 2001).…”

Modeling Fluid Reinjection Into an Enhanced Geothermal System

“…In multistage stimulation in oil and gas fields, fracture initiation is enforced at the perforations made through cement and casing which forms complex fracture patterns (Warpinski & Wolhart, 2016) along the horizontal wells. Most geothermal wells, on the contrary, are drilled with some deviation and completed with preperforated liners, aiming to intersect as many preexisting fractures as possible.…”