In recent years

some achievements have been made in oil

&

gas exploration in Hari sag

Yingen-Ejinaqi basin

but the exploration here is very difficult due to its complex geological conditions.Especially

with the deepening of exploration

previous research results of oil

&

gas sources can not meet the needs of fine exploration research.Based on the test and analysis data of crude oil

oil sand and source rock samples

Bayingebi Formation is subdivided into three segments(K

1

b

1

K

1

b

2

and K

1

b

3

from bottom to top)

then the fine oil source analysis is carried out

and the distribution prediction and characteristics evaluation of the main source rocks are carried out in order to clarify the source of oil and the characteristics of the main source rocks.The results show that carbon isotopes have a good indication for oil sources in the study area

the crude oil in main oil-producing segments of K

1

b

1

and K

1

b

2

mainly comes from K

1

b

1

and K

1

b

2

source rocks

respectively.Biomarkers such as acyclic alkanes

steroids

terpenes and aromatics also indicate the same conclusion.In particular

aromatic compounds have achieved good application results in this study.The maximum thickness of effective source rocks in K

1

b

1

is 151 m

and K

1

b

2

is 222 m

the two sets of main source rocks both with a large thickness in the study area.As for geochemistry characteristic of source rock in K

1

b

1

TOC averages at 0.89%

δ

13

C of kerogen ranges from -29.1‰ to -24.5‰

R

o

from 0.60% to 2.01%

the source rocks are characterized by medium-good organic mater abundance

Type Ⅱ

1

-Ⅱ

2

and maturity-high maturity.For source rocks in K

1

b

2

TOC averages at 1.18%

δ

13

C of kerogen ranges from -30.3‰ to -23.8‰

R

o

from 0.60% to 2.17%

the source rocks are good-excellent organic mater abundance

Type Ⅱ

1

-Ⅱ

2

and maturity-high maturity source rock.With high abundance of organic matter

and in the thermal evolution stage of the peak period of hydrocarbon generation

the two sets of main source rock both have a good hydrocarbon generation potential

and can provide a good hydrocarbon basis for oil

&

gas accumulation.