基于实测剖面资料，对川西北地区上二叠统长兴组、大隆组沉积特征进行了研究。结果表明：自晚二叠世长兴组初期以来，广元—梁平海湾属于上扬子台地内部产生的裂谷型同沉积拉张性断裂形成的海湾，鱼洞梁和坪上长兴组剖面发育浅水潮坪-开阔台地相，其间有生屑滩沉积，在坪上剖面见有尚未发育成熟的海绵生物礁；研究区北部的长江沟剖面则发育与长兴组同时异相的大隆组深水沉积，富含海绵骨针和放射虫。长兴组主要储集空间类型为粒间溶孔、晶间孔、裂缝型洞穴、构造缝及溶蚀缝等。综合而言，川西北广元—旺苍海湾边缘礁位于江油二郎庙与广元下寺之间，长兴组深埋地腹，是勘探地下生物礁-滩组合的有利地区。

Based on the measure d profiles , the sedimentary characteristics of Upper Permian Changxing and Dalong Formation are studied. The result shows that since fromthe early depositional stage of Late Permian Changxing Formation, Guangyuan-Liangping area is a gulf which formed by the rifted synsedimentary fault in Upper Yangtze Platform; in Changxing Formation in Yudongliang and Pingshang area in Jiangyou, there developed tidal and open platform, with bioclastic shoal, and there also developed immature sponge reefs in Pingshang area; in Changjianggou area in Jiange, there developed deep water sedimentation in Dalong Formation which is at the same stage with Changxing Formation, and it is rich in calthrop and radiolarians. The main reservoir spaces are intergranular dissolved pore, intergranular pore,fractured cavern, structural fracture and dissolved fracture. In a word, reefs at the margin of Guangyuan-Wangcang gulf are located between Erlangmiao in Jiangyou and Xiasi in Guangyuan, where Changxing Formation is deep buried, and they are the favorable area for exploration of underground reef-beach reservoir.