ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

Hydrocarbon Exploration with GORE Sorber Survey and Case Histories from
Turkey
Tuba Evren Sökmensüer, Kadir Gürgey
Merty Energy, Ankara
The majority of early oil discoveries until the 1950’s resulted from drilling wells near active seeps
or other surface features thought to be related to underlying hydrocarbon accumulations. This
led to the development of techniques referred to surface prospecting tools. Surface geochemical
techniques were first applied by Laubmeyer and Sokolov almost 60 years ago with both success
and failure. For over 50 years, oil & gas exploring earth scientists have developed and tested
methods which can image hydrocarbon filled reservoirs by measuring near surface parameters.
These traditional techniques have included direct soil analysis, active soil gas measurement and
microbial techniques. Unfortunately, these traditional methods suffer from some limitations
including the poor adsorptivity of soils in 1 of 5 exploration sites, sampling difficulty due to poor
soil permeability, low analytical sensitivity, limited data sets of C1-C5 hydrocarbons (methanepentane).
Modern surface geochemical technique is GORE Survey. This technique uses a
passive signal collector that can work in dry, saturated soils or directly in water. It is sensitive
enough to work in areas with overburden that are relatively impermeable and have extremely
low ppt concentrations. Over 150 volatile compounds, such as volatile gases like ethane, volatile
liquids like benzene or low volatility liquids and solids like pyrene, can be measured with high
accuracy. By combining the use of multivariate statistical techniques with this very sensitive
and rich compound data set this tool has broad application in the environmental, energy, and
mineral industries. Analysis is performed by thermal desorption/gas chromatography/mass
spectrometry which analyze each sample over a mass range that includes hydrocarbons from C2
to C20. The instrument can effectively detect alkanes, cycloalkanes, naphthalenes and aromaticsubstituted
aromatic compounds. With the use of compositions from the study area and statistical
interpretations of model dry/gas/oil wells, purposive anomaly maps are created. GORE methods
include frontier exploration, prospect evaluation, in-field development. Frontier area is used to
validate the petroleum system, evaluate leads and focus a seismic programme. In exploration
application GORE Surveys help to focus geophysical efforts, prioritize leads or investigate
charge in structural and stratigraphic traps. In older fields, they help to increase production and
build reserves by finding by-passed pay. In this study, surface geochemistry GORE method will
be discussed with case histories from Catalca, Alasehir , Ezine fields in Turkey.
Keywords: Hydrocarbon, surface geochemistry, goretm survey, surface hc prospecting, oil and
gas exploration, volatile organic compounds
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