Articles

Distributed Acoustic Sensing as a Fracture Diagnostic Tool

Paul Webster

Distributed Acoustic Sensing (DAS) is an acoustic detection technology that has recently been applied in production and geophysical settings. A single mode silica optic fiber in a cable is attached to a well bore and interrogated with laser pulses. An Interrogator Unit on the surface generates the laser pulses which…

Introduction to January Focus: Unconventional Reservoirs

Marco Perez

The promise of unconventional reservoirs is sustainable hydrocarbon production from previously inaccessible reservoirs. The high capital expenditure required to develop this resource and the depressed commodity prices makes for narrow profit margins and increases the focus on efficient and optimal project execution. Most of the focus is on lowering costs…

Hydraulic fracturing as a global cascade in networked systems

David Cho

Networked systems require the consideration of interactions between component parts as well as the parts themselves in understanding the properties of the system. In the case of hydraulic fracturing, the process can be regarded as the spread of a fractured state through an initially unfractured network of rock elements. In…

Unconventional shale gas reservoir characterization using the hitcube approach – The mapping of marl rich mudflows in the Horn River Basin

Claire Pierard, Hardeep Jaglan, Kristoffer Rimaila, Arnaud Huck, Friso Brouwer, Steve Jensen, Eric von Lunen

In unconventional reservoirs, the occurrence of marls is a significant risk to production and a major challenge to be able to locate and quantify them. As the marl thickness is often below the seismic resolution, an advanced characterization technique is needed. The HitCube inversion is an efficient stochastic inversion to…

The impact of interbed multiples on the inversion and interpretation of pre-stack data

Andrew Iverson

Unconventional resource plays commonly use a geophysical workflow involving analysis beyond stacked images and structural interpretation. This involves pre-stack quantitative interpretation methods such as inversion to obtain P-impedance and S-impedance (Zp and Zs) volumes that are then interpreted using rock physics and geomechanical templates (Close et al. 2012). The goal…

Breaking Structure: Why Randomized Sampling Matters

Felix J. Herrmann

During this talk, Felix Herrmann will explain how ideas from compressive sensing and big data can be used to reduce costs of seismic data acquisition and wave-equation based inversion. The key idea is to explore structure within the data by deliberately breaking this structure with randomized sampling, e.g., by randomizing…

Introduction to December’s Focus: Seismic Processing

Richard Bale

It is sometimes easy to forget, amidst the panoply of recent trends now enlivening geophysics – fractures, microseismic, reservoir monitoring, etc. – that much of our work relies on one main idea: extracting signal from data. In this issue, we revisit this basic principle and explore the implications in different…

Sparsity and band-limitation: Two sides of the same coin?

Mostafa Naghizadeh and Mauricio D. Sacchi

We introduce a strategy to identify the optimal sampling functions for Fourier reconstruction (5D interpolation) methods. We integrate the concepts of band-limitation and sparsity into a single decision criterion to select the sampling functions with the least amount of spectral interference in the Fourier domain. The analysis was carried out…

All roads lead to Rome: predictability, sparsity, rank and pre-stack seismic data reconstruction

Aaron Stanton and Mauricio D. Sacchi

In recent years researchers at universities, processing and oil companies have proposed several pre-stack seismic data reconstruction algorithms. In essence, all these algorithms are developed under a common assumption: there is sufficient simplicity in the observed seismic wavefield to permit its representation in terms of a finite number of basis…

A new, simple approach to surface-consistent scaling

Peter Cary and Nirupama Nagarajappa

Surface-consistent scaling has been a standard step in the processing of land seismic data for many years, especially in the preparation of pre-stack data for AVO analysis and inversion. Despite the fact that this type of process is in such common use, we believe that there is a basic problem…

2014/2015 Executive Election

Recorder Committee

Asteroseismology: Stealing the geoseismologists’ rule book and launching it into space

Jaymie Matthews

Astronomers have been trying to update the biography of the Sun for decades, at the same time trying to confirm our models for its internal structure. Like the Earth – of which we can sample directly less than 0.2% of its total depth – most of the interior of the…

Introduction to November’s Focus: AVO Inversion

Franck Delbecq

In this special issue on inversion, I have the honour of introducing three very interesting articles which all use inversion techniques as well as deductive, inductive and Sherlock’s abductive reasoning to crack (sometimes literally) the mysteries of our reservoirs.

Geophysical insights into completions and production predictability for a shale gas reservoir using fault intensity and AVO inversion

Carl Reine and Sean Lovric

We show that fault intensity and AVO inversion offer insights into hydraulic fracturing operations in a shale-gas reservoir. This is supported by microseismic data using calculations of event density, SRV dimensions, b-value, D-value, and hydraulic diffusivity. We also demonstrate that fault intensity is linked to the azimuthal anisotropy of the…

Using uncertainty in quantitative seismic characterization

Rémi Moyen

Over the past two decades, the overall trend has been for a more quantitative use of seismic in building geomodels and interpreting subsurface data. Acoustic seismic inversion has become commonplace, and more complex techniques tend to move closer to a direct modeling of petro-physical properties such as porosity or fluid…

Quantitative seismic interpretation – an earth modeling perspective

Damien Thenin and Ron Larson

Earth models are routinely used in the oil & gas industry to integrate multidisciplinary data for subsurface property predictions. While most earth models predict reasonably well at the field scale, they often fail to accurately predict the subsurface conditions at a specific location, especially in stratigraphically complex reservoirs.

Proceedings of an unsession

Matt Hall & Evan Bianco

Some time in 2012, we started to feel like we – those of us in this industry – were missing an opportunity (ageo.co/conffail). Some big conferences have five or ten thousand attendees. But that’s all most of them are – attendees. Not participants, or contributors, just spectators. They mostly sit…

Seismic Clustering Uncloistered – Application to Resource Plays

Kurt J. Marfurt

Clustering algorithms are used every day in marketing – from the good people at Amazon suggesting you buy a structural geology book based on your most recent purchase, to those at Google popping up a coupon on your smart phone when your GPS tells them you are once again standing…

Introduction to the special section on ‘Microseismic’

Bill Goodway

Passive microseismic monitoring has been a key technology used to map the stimulated portion of the reservoir through locating the sources of seismic waves generated by various modes of hydro-frac induced rock failure. The method was initially proposed as far back as the 70’s and published in a paper titled…

Microseismic Case Study: Getting the most from your microseismic survey

Michael Doerksen

A junior oil and gas company was preparing to develop the Cardium sand on their acreage in the Willesden Green area of Alberta. To optimally drain the acreage, horizontal well density and the number of frac stages employed using multi stage fracture stimulation was questioned. To answer this, they contracted…