Speaker: Christopher Smith, PhD
Subject: Rock Volatiles Stratigraphy in North Texas: Understanding How Offset Legacy Verticals and Modern Laterals Affect New Wells in Terms of Pressure Depletion and Communication and Prospecting for Helium in the TX/OK Panhandles
Abstract: Rock volatiles stratigraphy (RVS) has been pioneered and developed over the last ten years to provide actionable information to oil and gas operators based on detailed geochemical analysis of volatile components present in geological samples though recently this has expanded to include helium exploration, geothermal, and carbon capture storage applications. Samples analyzed are typically cuttings and core, but muds and produced fluids are also analyzed on the same instrumentation allowing for direct comparisons.
The RVS technique applies vacuum extraction to rock samples to provide quantitative information on entrained hydrocarbons (HC), organic and inorganic acids, noble gases, air components, various sulfur compounds, biodegradation compounds, and water. Two vacuum extractions, at 20 and 2 mbar, are applied to the same rock sample to obtain readily extracted and more tightly held compounds. Analytes are concentrated on liquid nitrogen cold traps (CT). When the CT is warmed after collection the analytes are released by sublimation point to a mass spectrometer for analysis. Non-condensable gases like methane and helium are analyzed prior to warming. Analysis at different vacuum extraction pressures allows for calculation of relative permeability indices, understanding surface/fluid interactions, and evaluating environments where compounds reside.
Past RVS work in and around North Texas has focused on oil and gas in the Granite Wash, the Barrnett, the Marietta basin, tight Pennsylvanian sands in across multiple countries, and helium deposits in and around the Oklahoma and Texas panhandles. These last two have been of particular interest to us at AHS given the unique challenges and opportunities presented. Two major case studies are presented, work in a tight Pennsylvanian sand target in Fisher and Scurry counties where past conventional production of shallower intervals has resulted in the reservoir being depleted of pressure. At the same time cuttings from the new lateral boreholes contain the signatures from the completion of laterals by offset operators carried out a few months prior indicating the laterals will likely be in communication upon completion and production despite being over 2500-3000 ft apart. RVS offered a unique opportunity to understand the effects of the past legacy vertical boreholes completion and production on the new laterals and the zones in the new boreholes which were actively encountering the effects of the completion, but not yet production, of the offset operator’s laterals. In addition to oil and gas, helium is a significant resource present in notable deposits in and around the Texas and Oklahoma panhandles with some of the richest helium concentrations in the US being located in Potter County TX and some of the largest historical fields being present in Cimarron County OK. Work with the Oklahoma Geological Survey to understand the subsurface helium system in the Keyes Dome field in Oklahoma and begin prospecting for new targets, in several cases using cores from the 1950s will be discussed. These studies will be supplemented from work in Kansas showing that RVS measurements of CO2 and other compounds can be directly correlated to pressures measured by DSTs and work done in Saskatchewan on helium to understand how it is retained in legacy core samples as a function of rock properties and phase.
Bio: Christopher Smith has been a Senior Chemist with Advanced Hydrocarbon Stratigraphy (AHS) since January 2019 and moved to Midland in 2022 working on data analysis, instrumentation, client engagements, and business development. Most of his analysis work focuses on the Permian, the Anadarko and Arkoma basins in Oklahoma, the North Slope in Alaska, and the Marcellus. Since 2020 a significant portion of Christopher’s work has been geared toward expanding the uses of AHS’s unique patented technologies into non-traditional fields for AHS beyond oil and gas – these include successful engagements and projects with academia, government, and operators on subsurface studies in carbon capture and sequestration, helium exploration, and geothermal power. Additionally, he has pushed AHS to be involved in scientific studies on permafrost in the Artic and the paleo environment before, during, and after the Chicxulub impact. Prior to working for AHS, he received his PhD in analytical chemistry from the University of Arizona with focuses on instrumentation, data analysis programing, spectroscopy, electrophysiology, surfactants, and surface modification chemistries. He also completed a MA in history at the University of Tulsa as a Henneke Research Fellow in 2012. He completed his undergraduate work cum laude in 2011 with degrees in chemistry, history, and biochemistry also from the University of Tulsa.