Abstract:

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 km²,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-P₁),transitional basin stage(P₂-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).