In recent years

hydrocarbon exploration in Turpan Depression

Xinjiang has obtained gratifying achievements.Three oil fields—Shanshan

Yilahu and Qiuling were discovered in succession.Turpan Depression

covering 28600 km

2

filled with Late Paleozoic and Meso-Cenozoic sediments.The deepest is Taibei subdepression with more than 9000m thick sedi-mentary rocks.The region experienced back-arc basin stage(D-P

1

)

transitional basin stage(P

2

-T)

intermountain basin stage(J-K)and foreland basin stage(E-Pre.).The Triassic and Jurassic sediments are not only the main source rocks of hydrocarbon

but also important producing formations.Up to now

52 local structures have been recognized by outcrop inspection and seismic exploration.45 traps(in different target beds)contained in 23 subtle structures were studied and analyzed with trap assessment method

thus setting up the parametric probabilistic standards of geological risk

volume coefficient and recovery factor

then the probabilistic values of geological nonrisk and recovery factor as well as the Potential re-serves were calculated with multiplication and Montecarlo method respectively.Finally

these traps were arranged in order with R

a

(multiple index for trap arrangement)and 23 structures were analyzed with comprehensive arrangement factor.The result shows that the most favourable structures for hydrocarbon exploration is Qiuling structure

then suc-cessively Shengjintai

Shengjinkou

Hongshan

Taibei and Punan structures.This predic-tion has been proved by discovery drilling in Qiuling and Taibei structures(shanshan oil-field).