Abstract
Hydrogen and helium detection can benefit drilling operations when combined with methane-through-pentane gas chromatography. The addition of hydrogen and helium analysis to surface detection can lead to lower-cost wells and possibly increased production.
In the oil industry, hydrogen has five sources, three of which are geological and two are manmade. The geological sources are basement rock, fractures, and liquid hydrocarbons, and the manmade sources are drill bit metamorphism (DBM) and mud motor failure. Helium has two geological sources—basement rock and faults. When hydrogen and helium detection are combined with gas chromatography, the source of the hydrogen and helium increases can be determined.
During geological analysis, hydrogen and helium spikes, where helium is present in much higher concentrations, without the presence of ethane, are indicative that a fault has been encountered. Porosity and/or permeability increases indicate a sustained increase in hydrogen and helium with an increase in methane. When liquid hydrocarbons are present, increased hydrogen concentrations with methane are detected, and the increase in hydrogen relative to helium is significant. Where drilling applications result in DBM and mud motor failure, hydrogen increases without a corresponding increase in methane or helium. Ethane and propane concentrations also increase with hydrogen during these events. Using this knowledge, changes in reservoir properties can be determined without relying on costly downhole tools while drilling. In addition, this information can be used in extended reach wells to identify faults and help geosteer the well. From a drilling perspective, such information provides confidence regarding identification of mud motor failure and bit drilling efficiently to help prevent costly bit trips.
Hydrogen and helium detection provides a low-cost alternative to costly downhole tools for providing real-time detection of faults, drilling inefficiencies, and relative porosity and permeability. This technology also provides a low-cost solution for well placement.
