油气分段捕获揭示震旦——寒武系天然气成藏过程

Sinian-Cambrian Natural Gas Reservoir Formation Shown by Segmented Capture of Oil and Gas

刘欢 李明隆 江林 夏吉文 王廷栋

LIUHuan LIMinglong JIANGLin XIAJiwen WANGTingdong

西南石油大学地球科学与技术学院, 四川 成都 610500 中国石油西南油气田分公司蜀南气矿, 四川 泸州 646000

School of Geosciences and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Shunan Gas Mine Field, Southwest Oil & Gas Field Company, PetroChina, Luzhou, Sichuan 646000, China

烃源岩生烃具有时间和空间上的序列性，构造活动和圈闭的形成也具有阶段性，加之富集型古油藏和分散型滞留原油产生的裂解气也会大量运移聚集，因此，油气成藏可能经历多个阶段。基于以上油气分段捕获原理"将今论古"地分析四川盆地南部威远、资阳、高石梯-磨溪3个典型构造的震旦系-寒武系天然气成藏过程与成藏规律，从而预测其他未知区块的成藏潜力。研究认为，高磨地区作为继承性古隆起，震旦系-寒武系圈闭几乎捕获了烃源岩从早期生油到晚期干酪根生气所有阶段的油气；威远、资阳震旦系-寒武系圈闭则仅捕获了部分阶段的油气，对于未知区块-泸州古隆起区来讲，其震旦系-寒武系能捕获生气高峰及其以后阶段所有的天然气，包括分散型滞留原油裂解气和晚期干酪根裂解气，如果落实好储层和圈闭，天然气勘探潜力很大。

Hydrocarbon generation from source rocks follows specific temporal and spatial sequences while tectonic activities and trap formation have different stages. In addition, large volumes of pyrolysis gases resulting from enriched paleo-reservoirs and scattered residual crude oil will migrate and accumulate. Therefore, reservoir formation may undergo multiple stages. The principle of segmented capture of oil and gas was employed to analyze the Sinian-Cambrian natural gas reservoir formation processes and patterns of the three typical reservoir architecture types. The studied reservoirs are the Weiyuan, Ziyang, and Gaoshiti-Moxi in the southern part of the Sichuan Basin. The reservoir formation probabilities of other unknown areas can thereby be estimated. It is concluded that, the Sinian-Cambrian traps in the Gaoshiti-Moxi Area, being a succeeding paleouplift, captured oil and gas formed during nearly all stages. This occurred from the early hydrocarbon generation from source rocks to the late-stage gas generation from kerogen. Meanwhile, the Weiyuan and Ziyang areas only captured oil and gas resulting from some stages. For an unknown area, namely the Luzhou Uplift, it is possible to capture the natural gas resulting from the peak generation stage and the subsequent stages. These include the pyrolysis gases from scattered residual crude oil and late-stage kerogen. If the configurations of the reservoirs and traps are well determined, the area has a great potential for natural gas exploitation.

10.11885/j.issn.1674-5086.2018.10.27.01