Geochemical Services

Development - Lithuania


Introduction

The survey area is located in the Baltic Syneclise petroleum province, Lithuania. Target was an on-shore marine Cambrian sandstone. Producing horizon is about 2,000 m deep. Reservoir traps are a result of Caledonian tectonism. Goal of the survey was to determine the field limits and identify reservoir sweet spots.



Survey Summary

  • Lithuania - Development
  • Producing oil field
  • 150 GORE® Modules installed
  • Sample spacing – 250 m to 500 m regular grid
  • Three economic oil wells drilled as a result of the GORE® Survey
  • Field production increased 12-fold

GORE® Survey

150 samplers were collected from a regular grid spaced 250 by 500 m covering an area of 20 km2. For statistical modeling purposes additional samples were collected at existing wells, known to be dry wells or producers of oil. Sample analysis was performed using gas chromatography and mass selective detection. An analysis for more than 80 target compounds was performed. Compounds observed included N-alkanes ranging from ethane through octadecane. By comparing the field samples against the modeled oil signatures, the similarities of each sample's signature to the local oil were established in terms of probability. The probabilities were contoured revealing surface geochemical anomalies.


Survey Results

The GORE® Survey defined elongated geochemical anomalies within the field. To date three producing wells (no dry wells) have been drilled on the positive geochemical anomalies. The production rates of the new wells were significantly greater than the rates from earlier wells (see table, below.)

The GORE® Survey identified reservoir sweet spots and increased field production 12-fold.

Figure 2: Production data before and after GORE® Survey.
Production/Test Data (BOPD)
Wells drilled before GORE® Survey Wells drilled after GORE® Survey
G-6/PS-1 160 PS-2 3,350
G7 120 PS-3 2,020
G11 dry PS-4 760
G12 750 (test)
G13 dry
G14 3 (test)
G18 120