依据构造演化史、生烃史和微裂缝密度,将龙门山北段前缘前陆盆地须家河组二段―三段含油气区带划分为梓潼凹陷西斜坡含油气区、梓潼凹陷东斜坡含油气区和九龙山含油气区。梓潼凹陷西斜坡含油气区须二段-须三段发育有4套大型砂体。在诺尼克晚期的表生作用下,该区砂体生成粒内-粒间溶孔,其后由于中深埋藏作用而发育微张裂缝;在燕山期大型砂体与古隆起构成复合型圈闭并继承性捕获油气。

The petroleum province, oil and gas bearing area ,of the Xujiahe formation second-third member in the north section of Longmen mount foreland basin were divided into three  parts: the Zitong sag west slop petroleum province, the Zitong sag east slop petroleum province and  the Jiulongshan petroleum province on the basis of its tectonic evolution, hydrocarbon generation history, the kinds of pore and density of microcrack in Xujiahe formation second-third member's sand bodies. The Zitong sag west slop petroleum province: 1.The Xujiahe formation second-third member's four huge overriding sand bodies are generated by quick aggradation of sediment in early-medium Norian stage; 2.The fresh water leaching during epigenesis late Norian stage results in the intragranular-intergranuler solution pore generating in these sand bodies; 3. Subsequently, the microcrack in these sand bodies grows as a result of the geostatic pressure or dynamic pressure in medium-deep buried diagentic enviroment; 4. These sand bodies and the huge ancient uplift constitute a huge ancient compound trap, which catchs oil and gas all time.