Defining Phase Specific Hydrocarbon Subsurface Reservoirs in the West Siberian Basin Using Amplified Geochemical Imaging™

Paul A. Harrington¹, Victor Ponomarev², and Aleksandra Abalmasova^3
1W.L. GORE & Associates, Inc., Elkton, MD.
²OJSC "Novatek", Moscow, Russia.
³W.L. GORE & Associates, GmbH, Putzbrunn, Germany.

In 2006 and 2008 an advanced surface geochemical prospecting tool capable of directly detecting and quantifying over eighty organic compounds in the C2 to C20 range was used in the Yarudey petroleum province.

The target interest is presented by Lower-Middle Jurassic Formation. Emanation of hydrocarbons from reservoirs is collected at the surface on engineered sorbents. These sorbents were placed within the boundaries of local seismic anticlines Shuginskaya and Yarudeyskaya, on the north and south of Yarudeyskaya uplift, in a regular grid pattern throughout the survey area, buried to a depth of 60 cm and were left in place for approximately 30 days.

Once retrieved all samples were analyzed by thermal desorption followed by gas chromatographic separation and mass selective detection. After signal to noise processing, statistical methods involving principle component, hierarchal cluster analysis and discriminate analysis are applied to the data set to define unique hydrocarbon signatures related to different hydrocarbon phases in the subsurface.

The geochemical survey was divided into two stages: on the southern Yarudeyskaya and northern Shuginskaya areas.

The objective of survey in the south was to define the prospects of oil and gas-bearing capacity for the drilling site selection.

The survey in the north was carried out to determine gas and condensate prospects similar to a recent gas-condensate discovery located 25 km south of the survey area. In addition to detecting a gas-condensate hydrocarbon signature, a new oil signature was also identified and mapped representing a potential previously unidentified oil reservoir.

The geochemical models results obtained in Shuginskaya area demonstrated two separate anomalies; one is related to a gas-condensate signature and the other to an oil signature. Almost 80 meters of net oil pay in middle Jurassic reservoir rocks was discovered by the well drilled within the oil anomaly. More the 50 meters are oil saturated. During testing of this bore hole a fountain of oil was obtained.

Based on results of the geochemical studies as well as exploration drilling, the Amplified Geochemical Imaging method is able to detect, differentiate and map different hydrocarbon phases associated with the subsurface reservoirs even in such difficult climatic and geological conditions as in the north permafrost of West Siberia.

AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia