Abstract

Over the last several years imports of foreign oil into the United States of America have decreased largely in part due to the proliferation and output of unconventional plays. However, as the price of natural gas has continued to drop, companies focused on resource plays are now directing their attention to shale oil and shale condensate to remain profitable. Thus it becomes paramount for technologies to emerge that can correctly characterize areas of dry gas, wet gas, and oil, as well as identify potential transition zones between them.

Additionally, it is becoming increasingly obvious that shale plays are nonhomogenious structures and all vertical sections within a zone are not created equal. A recent article about unconventional plays in the March 2012 issue of the AAPG Explorer stated, “A reservoir is a 3-dimensional section of earth” and “People are integrating 3-D with as much borehole data that are available at the start of the workflow and throughout the process”.

GORE’s Amplified Geochemical Imaging and Downhole Geochemical Imaging technologies are two applications that work together to provide data for unconventional exploration success. Amplified Geochemical Imaging is a direct surface hydrocarbon measurement technique that measures the vertical migration of volatile hydrocarbon compounds from subsurface reservoirs. These microseepage hydrocarbon compounds, up to C₂₀, can be captured and measured at the surface resulting in the ability to identify and map subsurface hydrocarbon systems as well as clearly differentiate between various hydrocarbon phases, such as gas, condensate, or oil. These hydrocarbon maps can then be used to demarcate transition lines between the various hydrocarbon phases and direct exploration efforts to areas of higher profitability.

This technology can also be utilized in conjunction with downhole cutting samples to directly characterize the composition of hydrocarbons vertically through the prospect section. This methodology has the unique ability to look at a broad compound range from C2 to C20, which is significantly more expansive than the limited traditional ranges of C1-C5 or C1-C10 of most well gas logging techniques. The result is a broad characterization of petroleum phase contained in the stratigraphic intervals down the well.

This data may be used to:

• Correlate with electronic and nuclear logging results to better define test intervals of interest

• Identify preferred completion zones and petroleum phase (gas, condensate, oil)

• Reduce testing/completion costs and time

• Evaluate seal rock integrity

• Better understand petroleum migration patterns and petroleum phase differences between source, migration, and reservoir rocks

• Potentially understand vertical compartmentalization

Case studies will illustrate that GORE’s horizontal approach of Amplified Geochemical Imaging technology and GORE’s vertical approach of Downhole Geochemical Imaging provides a 3-Dimensional approach to evaluating resource plays.