UNDERLYING IMPORTANCE OF REFERENCE SYSTEMS IN HYDROCARBON EXPLORATION AND PRODUCTION

G.O. Alvarez

RepsolYPF

galvarezg@repsolypf.com

 

Geociences focused on hydrocarbon exploration need to know the location, as referenced to the Earths surface, of the elements required to conduct their activity.

The difficulty in locating any element on the Earths surface using a coordinate system lies in the fact that the Earths surface is neither smooth nor flat.

Hydrocarbon exploration in Argentina began in the first decade of the 20th century, i.e. several decades before the Military Geographic Institute (IGM, Spanish acronym) established a high-precision national geodetic network.

The need to select locations for wells drilled in the early stages forced YPF, the state-owned oil company, to make the local networks initially established by IGM denser. Therefore, each sedimentary basin in which exploration activity was conducted, was provided with its own geodetic reference network.

The Campo Inchauspe system was created later and was taken as the national and official geodetic system until 1997, when the Posgar 94 system was designated as official. A third system was thus added to each basin, which forces us to pay further attention to major geodetic issues areas when performing geologic studies, recording seismic data, delimiting a mining claim and proposing an exploratory well.

Offsets ranging from 50 to 600 m between geodetic systems may cause several problems. Drilling a dry well is probably the most serious one.

For several decades, location errors resulting from disregarding the geodetic system used went unnoticed and were considered part of the exploration risk.

The purpose of this paper is to highlight the underlying importance of the geodetic reference system in hydrocarbon exploration and suggest improvements for appropriately managing the quality of data that is most responsive to the hydrocarbon business, particularly the selection of the right reference system. And eventually help minimize the impact of a usually disregarded and difficultly quantifiable risk on exploration activity.