Articles

A Gassmann-consistent rock physics template

Brian Russell

In an unpublished CREWES report, Russell and Smith (2007) use measurements from Han (1986) to evaluate two different approaches to the modeling of Kdry versus porosity in clean sands: the pore space stiffness method and the critical porosity method. For the range of porosities found in the Han sandstones, Russell…

Joint simultaneous inversion of PP and PS angle gathers

Dan Hampson and Brian Russell

We present a new approach to the joint simultaneous inversion of PP and PS angle gathers for the estimation of Pimpedance, S-impedance and density. Our algorithm is based on three assumptions. The first is that the linearized approximation for reflectivity holds. The second is that PP and PS reflectivity as…

Clarifying Dataroom Confusion

J. Douglas Uffen

Geophysical datarooms are an important element of business in the resource industry. They are staged for many reasons such as: when a company undertakes a sale process of assets or properties, during a Show & Tell presentation, or a farm-in process to attract new investors. Confidentiality Agreements (CAs) are often…

The Interpreter’s Guide to Depth Imaging

Scott MacKay

Compared to time migration, depth imaging should yield simpler structure, higher spatial and vertical resolution, and a more stable phase response. It is also the appropriate input for inversion and other attributes that estimate reservoir properties and mitigate risk. However, the interpreter must actively guide the depth-imaging process to ensure…

Introduction to Unconventional Gas

Manika Prasad

Recent years have brought a rapid expansion of activities around shale gas. The successes in shale gas exploitation have been mainly attributed to advances in engineering. In particular, hydraulic fracturing has contributed immensely towards this success. To date, geophysics has yet to assume a major role in the development of…

Assessing Knudsen flow in gas-flow models of shale reservoirs

Utpalendu Kuila, Manika Prasad and Hossein Kazemi

Shale reservoirs are characterized by extremely small pores and very low permeability. Detection and quantification of these small pores is a challenge. Furthermore, in such small pores, the gas flow need not flow in a Darcy flow regime. The Knudsen diffusion and slip flow gain significance and might account for…

Characterization of sandstone reservoirs using Poisson impedance inversion

Ritesh K. Sharma and Satinder Chopra

We demonstrate the application of Poisson impedance (PI) inversion for characterizing sandstone reservoirs encased in shale, when the impedance contrast between them is very small. Poisson Impedance is defined as the difference between the P-impedance (IP) and a scaled version of the S-impedance (IS), where the scalar (c) can be…

Conventional approach for characterizing unconventional reservoirs

Ritesh K. Sharma and Satinder Chopra

Shale resources characterization has gained attention in the last decade or so, after the Mississippian Barnett shale was successfully developed with the application of hydraulic fracing and horizontal drilling. For characterization of shale gas formations different workflows using 3D surface seismic data have been introduced. We propose an integrated workflow…

Estimating the value of Geophysics: decision analysis

Lee Hunt

This paper discusses the value of geophysical data in the resource play paradigm. Specifically, it shows how well known decision analysis techniques can be applied to estimate the value of seismic for resource play examples. We examine the sensitivity to the accuracy of the seismic interpretation and to the spread…

Elucidating Paleo Depositional Environments from 3D Seismic ‘Solving for One Part of the Hydrocarbon Accumulation Puzzle’

Trevor Johnson

Seismic data has been utilized in oil and gas exploration since around 1928, with early efforts directed at revealing the gross structural and trap configuration in what was then the frontier areas.

However, over the intervening time the technique has been continually refined and improved upon with modern 3D prestack…

Unconventional Petroleum Resources and “Hubbert’s Peak”

Laurence R. Lines

Long-term predictions of world petroleum supply are generally risky at best. Such predictions are often in error since they do not account for new discoveries, volatile political climates, and the wide variation in oil prices over time.

There is one prediction that (until recently) was considered to be an accurate…

PP time delay and PS splitting anomalies in the reservoir of an active THAI® project

Kurtis Wikel and Rob Kendall

Heavy oil recoveries in most heavy oil reservoirs in Western Canada are usually less than 10% under primary recovery schemes (native pressure and oil saturation). Thermal methods have been utilized in the Saskatchewan heavy oil region by many operators as a profitable alternative to traditional enhanced oil recovery (EOR) schemes.…

Synthetic seismograms, Synthetic Sonic Logs and Synthetic Core

Laurence R. Lines and Mahbub Alam

In geophysics, we often model or “synthesize” measurements in order to enhance our interpretation of geophysical data. Synthetic seismograms often utilize sonic and density logs to produce impedance profiles in order to model seismograms in order for us to pick reflections on seismic data. Synthetic sonic logs, as initially described…

Interpretation of Time-Lapse Seismic Data from a Heavy Oil Field, Alberta, Canada

Byron Matthew Kelly and Donald C. Lawton

Two 3-D seismic datasets and their difference volume were interpreted and analyzed for the presence of amplitude anomalies and time delays related to the injection of steam into a shallow, heavy oil reservoir. High amplitude anomalies were observed on the monitor data in conjunction with apparent time-thickening of the reservoir…

On the Characterization of Unconventional Oil Reservoirs

N.A. Solano, C.R. Clarkson, F.F. Krause, S.D. Aquino, and A. Wiseman

Oil production from low-permeability strata in the Western Canada Sedimentary Basin (WCSB) is continuously increasing, rivaling the production potential from conventional targets in the same areas. This increase in productivity is related to important advances in drilling and completion technology that are driven, in particular, by improvements in multi-fractured horizontal…

Predicting hydrocarbon production capacity in an unconventional reservoir from seismic derived elastic properties

Gorka Garcia Leiceaga, Mark Norton, Joël Le Calvez and Freia Henery

Seismic-derived elastic properties may be used to help evaluate hydrocarbon production capacity in unconventional plays such as tight or shale gas. By combining prestack seismic and well log data, inversion-based volumes of elastic properties may be produced. Moreover, a petrophysical evaluation and rock physics analysis may be carried out; thus,…

Seismic modelling of unconventional reservoirs

Marco Perez

Unconventional resource development has become an exercise in determining where horizontal wells should be placed to maximize hydro-fracture efficiency. A large part of optimizing how the resource is developed requires understanding the reservoir from both lithologic and rock properties perspectives and correlating these with production data to infer frac efficiency.…

How to maximize recoverable reserves in an unconventional reservoir using reservoir characterization from 3D seismic: a Barnett Shale Case Study

Roxana Varga, Ted Holden and John Pendrel

Producing commercial quantities of petroleum and natural gas from organic rich shales was uncommon a decade ago. Due to improved technologies and strengthening in the price of petroleum, activity in unconventional shale projects has increased significantly, particularly as more and more oil reservoirs have been identified. Maximizing recoverable reserves is…

Recent developments in microseismic monitoring: Introduction to the focus issue on Microseismic

David Eaton and Mirko van der Baan

Increasingly widespread use of passive methods to monitor hydraulic fracture treatment programs is driving technological advances that are changing how microseismic data are acquired, processed and interpreted. This focus issue of the Recorder contains a series of 4 articles that deal with a variety of research topics varying from acquisition…

Optimization of a Shallow Microseismic Array Design for Hydraulic Fracture Monitoring – A Horn River Basin Case Study

Paige Snelling and Neil Taylor

Many considerations go into the design of a surface or nearsurface array for microseismic monitoring. These include aspects of the array itself such as the number of stations, the station depth and density, array aperture, shallow geology as well as the geology of the target formation and completions design. Other…