Objective
DEVELOPMENT OF A NEW TECHNIQUE TO DETECT SUBSURFACE SOURCE ROCK BASEDDevelopment of a new technique to detect subsurface source rock based on natural seepage of hydrocarbons from the subsurface. The combination of seismic survey and geochemical survey was proved to give important information for petroleum exploration.
An easy and safe technique was developed to recover mundisturbed samples at ambient pressure from the sea bed. The samples was analyzed for their content of traces of hydrocarbons and nitrogen trapped in the soil. The purpose was to determine the type and the age of source rock for hydrocarbon generation.
The main conclusions of the project are :
- An ambient pressure drop sampler (the Soderberg sampler) has been developed and successfully tested.
- Free gas and adsorbed gas from 154 samples was analyzed. A good correlation between high gas anomalies and subsurface structure indicate that migration may be correlated with the subsurface fault pattern.
- By gas chromatography and carbon isotope analysis it was possible to distinguish between biogenetic and thermogenetic gas.
- Attempt to correlate nitrogen gas to the subsurface structure failed probably due to atmospheric contamination of some of the samples.
Geochemical exploration for oil and gas is based on the fact that light gas migrate from deep source rock to the surface. By taking undisturbed samples from the sea bed and analyze the gas concentration it is possible to get an indication of any subsurface source rock.
The method has to be used in combination with seismic interpretation and other geological studies e.g. basin modelling as a useful additional source of information.
The gas may be present either as free gas dissolved in the pore water or as gas adsorbed on the grain surface. One of the problems by analyzing the free gas has been risk of atmospheric contamination and escape of free gas from the sample when the pressure is released.
To overcome these problems a new ambient pressure sampler has been developed and tested. Laboratory equipment has been developed to extract the gas from the sampler without atmospheric contamination.
A successful pilot test was carried out in West Baltic. 154 sea bed samples was recoveredfrom 64 locations. A comprehensive laboratory programme was carried out including sediment analyses, gas chromatography (GC) and mass spectrometry (MS). The laboratory results were analyzed and compared with structured maps of the survey area.
The project is divided into 5 phases comprising 12 activities :
PHASE 1 : CONCEPTUAL STUDIES
- - Geochemical analyses, literature survey
- Isotope measurement study
- Core sampling requirements
PHASE 2 : DEVELOPMENT OF A CORE SAMPLER
- Design of equipment
- Construction and test
- Marketing
PHASE 3 : PILOT TEST
- Selection of test areas
- Field work
- Laboratory work
PHASE 4 : FINAL EVALUATION
- Evaluation of GENIUS results
PHASE 5 : REPORTING AND PROJECT MANAGEMENT
- Reporting
- - Project Management.
Programme(s)
Topic(s)
Data not availableCall for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
2800 Lyngby
Denmark