Comparing Formation Evaluation Measurements Made Through Casing with Openhole Logging Measurements

James Hemingway

Schlumberger

Abstract:There are numerous reasons for making traditional openhole measurements after casing has been set. Some of these reasons include difficult logging conditions, highly deviated wells where deployment is a problem, or simply avoiding expensive rig time. The increasing numbers of horizontal wells, especially in unconventional reservoirs, has led to a trend where the majority of new horizontal wells are not logged. Logging While Drilling or deployment of wireline tools in long horizontal openhole sections are often not an option due to cost or risk factors associated with deployment. Logging after the well has been cased can offer a greatly reduced risk as well as reduced cost.

The introduction of pulsed neutron capture measurements nearly 50 years ago provided some of the first opportunities to do formation evaluation in cased wellbores [Raymer and Morris, SPWLA Paper G 1964]. Over the years, new cased hole measurements have been introduced to make measurements previously only observed in openhole.

It is not my intention to suggest that logging in cased wellbores provides better data than what can be achieved in openhole. However in many cases it is possible to acquire the necessary data in cased holes to allow for a better completion design. Nowhere is this more useful than in the complex wellbores of today where we often have no formation evaluation data on which to base our completion.

Biography:  
James Hemingway started with Schlumberger in 1980 and has held various petrophysics and engineering positions with Schlumberger since 1982. He has been heavily involved in reservoir monitoring of Enhanced Oil Recovery operations using techniques designed for use in cased wellbores. James holds degrees in chemistry and chemical engineering.
In 1997 he joined the Formation Evaluation department at the Schlumberger Sugar Land Product Center working on the RSTPro* (carbon-oxygen) tool and "Three-Phase Holdup" interpretation techniques. He moved to Paris in 2001 as a new technology advisor and has been based in Houston since 2010 as a Petrophysics Advisor focusing on unconventional resources.
James was a Distinguished Lecturer for the Society of Petrophysicists and Well Log Analysts in 2000-2001 and 2011-2012 on cased hole logging technologies.