The Application of Geo-Microbial Hydrocarbon Detection and “4G” Comprehensive Research of Progressive Exploration in the Gudong Area, Shengli Oilfield

Abstract

Gudong area of Shengli Oilfield is a highly matured field for exploration and development. Progressive exploration and development is used as a major tool for improving production and tapping production potential of the area. Progressive exploration targets mainly are lithology, stratigraphy and other complex subtle reservoirs. However, it is difficult to identify traps simply by applying seismic analysis in the area, and previous studies proved that the water and oil contacts were very complicated. An effective hydrocarbon detection method is urgently required in the area to identify whether lithologic traps containing hydrocarbon and to make an exploration breakthrough in the stage of progressive exploration. Geo-Microbial Hydrocarbon Detection(GMHD)technology is a maturing and economically effective method for petroleum exploration, which is developed upon a significant but underutilized geological principle that hydrocarbon microseepage is present vertically above buried oil and gas reservoir. It combines a quantitative biological method with a qualitative geochemical method to make reliable detection and interpretation of hydrocarbon microseepage. GMHD technology can be applied to forecast the existence, distribution and properties of hydrocarbon accumulations. In 2015, a GMHD survey is executed to evaluate Trap A and B in Gudong in an area of 15km2. A 125m*125m grid is designed and 226 soil samples were collected. By applying GMHD survey, the results revealed that GMHD exploration findings matched well with previous drilling results. Trap A and B which were identified by 3D seismic survey turned out to have opposite hydrocarbon detection result. Trap A was located in Microbial background area and Trap B was located in Microbial anomaly area. After GMHD survey, one well was drilled on the trap B and it encountered commercial oil flow at Eogene Shahejie Formation. The original drilling plan on Trap A was then cancelled based on GMHD findings. By applying“4G”comprehensive research model which combines Geology, Geophysics, Geochemistry and Geobiology data for integrated study, heavy oil from Guantao Formation and normal crude oil from Shahejie Formation were identified by the diagram of C1/C2+C3 vs, C2/C3+C4 Sorbed Soil Gas Analysis. It is proved that GMHD technology and“4G”comprehensive research is precise and effective in detecting hydrocarbon for Progressive Exploration purpose. The application of the technology can significantly reduce exploration and drilling costs.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017