Petroleum Geochemistry Division – Rig Based Analyses...

GEOTECH offers a range of rig-based geochemical analyses which can be performed in conjunction with the drilling program. The main purpose of this service is to help wellsite geologists determine whether an oil column has been intersected, and to broadly characterise the liquid hydrocarbons as and when they are collected. The analyses make available information not provided by traditional well site techniques and are particularly useful when synthetic based mud systems are used.

The analyses conducted on the rig are based on standard techniques used in GEOTECH's Perth-based laboratory; however, they have been adapted to make them portable and practical in a well site setting. Specially developed geochemical sample preparation techniques (eg alkene removal) are also employed to maximise the quality of the on-site data.

Advantages of GEOTECH’s on-site program:

      Analyses are particularly useful when synthetic based mud systems are used            as they can help distinguish between contaminants (mud system) and naturally            occurring hydrocarbons.

      Results are usually available within 1 hour of sample receipt.

      Characteristic fingerprints of the hydrocarbons from approximately C10 to C30 (if            present) are provided.

      Different groups of naturally occurring hydrocarbons can be distinguished, as            they are intersected downhole.

GEOTECH’s on-site program...

Rig-based analytical programs are designed on a well-by-well basis after thorough consultation with the client. The mud system to be used in the well is characterised by GC-MS prior to drilling in order to fingerprint the mud and set a ‘baseline’ for future on site characterisation. As drilling proceeds, mud samples and/or cuttings samples are taken at regular intervals and analysed in a similar manner to the initial mud sample. Comparison of the data can identify when an oil column is intersected and the type of hydrocarbons that have been collected.

There are a number of logistical issues that must be addressed when planning a rig-based program.

There are a number of logistical issues that must be addressed when planning a rig-based program. Please CONTACT one of our geochemical staff for more information on this service.