Chapter 3 - Geology of helium, carbon dioxide, and nitrogen case histories and sources

Abstract

The number of case histories in the literature is somewhat limited for He and CO2 and nonexistent for any N2-producing fields. This chapter brings together in a general sense a large number of case histories around the world where possible. The majority of field descriptions and summaries are generally almost all in the United States. The remaining rest of the world is more in terms of general summaries or general speculation based on limited data. Helium fields can be categorized by their host gas: CO2, N2, and CH4. However, this does not necessarily identify the source of the He or if it has any relationship with its host gas. The amount of literature on the Texas Panhandle–Hugoton Field is significant, but unfortunately this is a supergiant accumulation with very unique geologic characteristics that have not been found elsewhere to date either with a similar areal extent in size or on a smaller scale. Unique deposits such as the Virginia Gas Field in South Africa are probably repeatable locally but in terms of the grander scheme in exploring around the world are one-offs and not repeatable elsewhere. The majority of the He in the world is produced from five fields or facilities in the United States (Texas Panhandle–Hugoton and Big Piney–La Barge fields), Algeria, Qatar, and Russia. The three fields are supergiants in terms of natural gas or CO2 production and would typically be found early in petroleum exploration or development in a basin or country. Therefore, the vast majority of He case histories presented here are for small to medium size deposits whose economics and reserves are more for the small to medium type company that can nimbly explore and develop them. Carbon dioxide fields and production seem to be typically the bailiwick of large multinationals because of the specialty type materials required to transport the compound to where it is going to be used. From the He case histories, we can generally conclude that the element is found structurally trapped mainly in Paleozoic age reservoirs, relatively shallow, near basin edges, and with primarily N2 and CH4+ host gases. The fields where CO2 is the dominant host gas with He seem to be more of an oddity than part of a typical relationship with He. This chapter is designed as a general guide and model for exploration.