蓬莱——苍溪——龙岗地区生物礁地震识别与展布特征  

Seismic identification and distribution of the bioreef,Penglai-Cangxi-Longgang block,Sichuan Basin

作　　者：李坷芮 代瑞雪 张旋 邹定永 孙豪飞 徐亮 梅花浪雪 李承泽 LI Kerui;DAI Ruixue;ZHANG Xuan;ZOU Dingyong;SUN Haofei;XU Liang;MEI Hualangxue;LI Chengze(Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China;Research Institute of Petroleum Exploration and Development-Northwest(NWGI),Petro-China,Lanzhou,Gansu 730020,China)

机构地区：[1]中国石油西南油气田公司勘探开发研究院,四川成都610041 [2]中国石油勘探开发研究院西北分院,甘肃兰州730020

出　　处：《天然气勘探与开发》2025年第1期11-19,共9页Natural Gas Exploration and Development

基　　金：中国石油天然气股份有限公司攻关应用性科技重大专项(编号:2023ZZ16YJ04)。

摘　　要：近期在四川盆地蓬溪—武胜台凹钻遇的2口井在上二叠统长兴组获得高产气流,显示该区块具有较大的天然气勘探潜力。虽然前期已在开江—梁平海槽西侧陆续发现了龙岗、元坝等大型台缘礁滩复合气藏,但因不同区域发育生物礁的形态特征不同,地震响应特征多样,对蓬莱—苍溪—龙岗地区礁滩体分布规律的认识目前尚不清晰。为此,综合钻井及地震资料,结合正演模拟及古地貌刻画,进一步明晰了该区长兴组生物礁展布特征及天然气勘探潜力。研究结果表明:(1)蓬莱—苍溪—龙岗地区长兴组可划分为7个地震相,整体总结为“一洼”“一台”“一槽”,“一台”内部又可进一步划分为“三隆两凹”;(2)该区共发育孤立丘状台内塔礁、台内点礁群、宽缓丘状台缘礁、锯齿状台缘礁、横向并积台缘礁、纵向加积台缘礁6种模式生物礁滩体;(3)蓬溪—武胜台凹东侧“Y”字形台缘带天然气勘探有利区面积达942 km^(2),苍溪剑阁高带礁滩异常带面积为498 km^(2)。结论认为:苍溪高带与元坝南区具有较强的可类比性,具有较大天然气勘探潜力。Substantial gas flow has been achieved from the Permian Changxing Formation in both two wells of Pengxi-Wusheng platform sag recently,indicating great natural-gas exploration prospects in this block.The distribution of bioreef-beach bodies in Penglai-Cangxi-Longgang block is not yet clear due to different morphological characteristics of bioreef developed in other blocks and diverse seismic-response characteristics even though some large platform marginal bioreef-beach composite reservoirs such as Longgang and Yuanba were discovered on the western Kaijiang-Liangping trough in the early days.Therefore,based on drilling and seismic data,both distribution and exploration prospects were figured out for Changxing bioreef reservoirs in this block through forward modeling and paleogeomorphological characterization.Results show that(i)this Changxing Formation here can be divided into seven sorts of seismic facies which are summarized as"one depression","one platform"and"one trough"And"one platform"can be subdivided into"three uplifts and two sags";(i)there developed six bioreef-beach bodies,including isolated hummocky intra-platform pinnacle bioreef,intra-platform patch bioreef group,large-scale gentle hummocky platform marginal bioreef,jagged platform marginal bioreef,horizontally and vertically deposited platform marginal bioreef;and(ii)the Y-shaped platform margin on the eastern Pengxi-Wusheng intra-platform sag,as a favorable area,is 942 km^(2)while the abnormal bioreef-beach belt in the higher belt of Cangxi-Jiange region of 498 km^(2).In conclusion,with strong comparability,both the higher belt of Cangxi region and southern Yuanba zone have great prospects in natural-gas exploration.

关 键 词：晚二叠世 生物礁 地震响应 古地貌 分布规律 勘探潜力 四川盆地 

分 类 号：P631.4[天文地球—地质矿产勘探] P618.13[天文地球—地质学]