PESGB Evening Lecture: June 2021

Speaker: Spencer Quam, Principal – Quam Energy Development

Topic: Improving Exploration/Development Opportunities from Legacy Seismic Data with Pre-Stack Processing

In the July 2019 AAPG Explorer, Chopra and Sharma showed examples of using data processing steps typically used to improve imaging of post-stack data, but applied to pre-stack data. During several assignments in the past, the speaker has applied similar methods to improve not only legacy 2D seismic, but also newly acquired 3D seismic. The driver for these reprocessing efforts was to improve image quality in areas where recording new data was cost prohibitive or not possible due to revised regulations or access problems.

The processing steps include pre-stack common offset noise reduction, detailed horizon-based velocity analyses in the dip direction, and pre-stack migration. In several 3D cases, the data were re-binned to orient the “inline” direction perpendicular to the regional faulting and dip, to allow for better fault resolution via horizon velocity analysis.

Prestack FXDecon Example (courtesy BHP)

Horizon Velocity Analysis Example (courtesy BHP)

In several cases, testing was done in-house and then used to convince JV partners to reprocess entire datasets.

In some examples the uplift was quite significant and usually simplified the fault interpretations, and in fact changed the tectonic setting of the faulting. It is key to identify fault behaviour with depth, whether faults sole out or connect with deep seated tectonic faults, such that reservoir faulting makes sense and potential footwall opportunities are recognized.

Several examples will be shown. In Congo – Brazzaville, the pre-salt syn-rift image was significantly improved adding prospectivity. In Australia, updip oil was identified in 2 legacy fields and later proven with new wells. Also in Australia, faulting resolution was improved such that later unitization had less uncertainty. And in Algeria, the reservoir and faulting image was greatly improved allowing horizontal wells to be accurately placed near updip bounding faults.

In the current environment with severely curtailed exploration and development activity, there is the opportunity to improve older datasets. These techniques can inexpensively provide improved images for better resource estimates and future new data acquisition planning.  As well, these techniques could be applied to high resolution, near surface seismic and perhaps ground penetrating radar data to improve imaging for geotechnical / hazard applications.

Spencer Quam, Principal – Quam Energy Development

Spencer Quam has a career spanning 40 years in the Upstream Oil and Gas Business. He is currently a consultant for international energy projects and for upstream training.  Experience includes Exploration and Development projects in 22 countries, many in-country, in North America, Austral-Asia, Africa, South America and Europe. Last assignment was as Chief Geologist for Galp Energia in Lisbon Portugal.

He holds a BSc in Geology from Western Illinois University, MSc in Geophysics from Stanford, and an MBA from St. Mary´s College of California.  He is a member of multiple professional societies, a fellow of the Energy Institute, a UK Chartered Scientist, and California Registered Geologist and Geophysicist.  He is also a volunteer on the Stanford Petroleum Investment Committee, the Committee for Professional Development for the Energy Institute in the UK, and a volunteer lecturer / panelist for Stanford School of Earth, Energy, and Environment and Saint Mary’s School of Economics and Business Administration.

This event is kindly hosted by: