The Research Of The Relationship Between Fracture System And Hydrocarbon Accumulation In Yongxin Area

There is great potential for oil and gas resources in Yongxin area, but fracture system is very complicated, fracture evolution and its relationship with oil and gas accumulation is unclear. In this paper, at the base of previous studies, guided by structural geology, petroleum geology, comprehensive utilization of high-precision three-dimensional seismic, logging, analysis data, fracture geometry, fracture evolution, hydrocarbon accumulation elements were researched, relationship between fracture and hydrocarbon accumulation were comprehensive analyzed, it is important for digging exploration and development potential, reducing the exploration risk, and providing reference materials for the next step exploration.From 3D seismic data, fracture geometry characteristics and activity characteristics were researched quantitative in Yongxin area. There are a lot of fractures in study area, including the second class fault which contains tree trend: EW, NEE, NWW, the third class fault which contains NS, EW, secondary to NE, NW trend, the fourth fault contains all of direction trend. Studied by fracture activity and evolution, we get that stretching exercises was significant in ancient Tertiary, in which large fractures were formed, basin evolution stepped into the depression stage, in which fractures activity weakened and stopped gradually.Comprehensive utilization of drilling, logging, geochemical data, hydrocarbon accumulation elements were studied in study area, we get mudstone in the upper part of the fourth member of Shahejie formation, the middle part of the third member of Shahejie formation, and the lower part of the third member of Shahejie formation is major source rocks; fine sandstone and siltstone in the upper part of the third member of Shahejie formation, the second member of Shahejie formation and turbidite glutenite in the fourth member of Shahejie formation, the lower part of the third member of Shahejie formation is reservoir; mudstone in the first member of Shahejie formation and Minghuazhen formation is cap rock.Using various methods, we determined accumulation period in the Minfeng depression and the central uplift, main fault is an important way for oil and gas migration in Yonganzhen oil field, only part of fault is the way for oil and gas migration in Xinlicun oil field, sandstone and fault constitute three-dimensional oil network of oil and gas migration, the regional cap rock and fault preserved oil and gas together.