Madong thrust belt is a trailing imbricate fan developed from NW to SE, the No.l,No.2 and No.3 fault were tbrmed just before Sangtamu lbrmation deposited. The No.4 and No.5 fault were formed after Sangtamu formation de- posited. The south part of the thrust belt were in the karst slope of Hetian paleo uplift, the Ordovician karst reservoir most non filled. The No.l,No.2 and No.3 fault in south part were reactive in late Hercynian, which could formed many fracture-cave system. The salt of middle Cambrian in the south part were thinner than that in the north part of Madong thrust belt, and the Cambrian source rock＇s peak oil generation window were just in late Hercynian, oil can migrated eas- ier from source rock to the lower Ordovician formation by the reactive faults than by the non-reactive fault of north part, so there should more oil cumulated in weathered karst of Ordovician in the south part. In Madong thrust belt, capping by the salt of Middle Cambrian, only part of the hydrocarbon could migrated to upper formations, a considerable part of hy- drocarbons were still in the Middle-Lower Cambrian, which have good exploration potential.
Madong thrust belt