川西北前陆扩展砂箱物理模拟及其深层晚期扩展变形特征

Analogue experiments on the piggyback propagation in northwestern Sichuan and latest propagation in its deeps

罗强 何宇 黄家强 张静 梁霄 于豪 杨荣军 邓宾

LUO Qiang HE Yu HUANG Jiaqiang ZHANG Jing LIANG Xiao YU Hao YANG Rongjun DENG Bin

成都理工大学"油气藏地质及开发工程"国家重点实验室, 成都 610059 中国石油 塔里木油田分公司, 新疆 库尔勒 841000 中国石油勘探开发研究院 四川盆地研究中心, 成都 610094

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China Research Center of Sichuan Basin, Petrochina Research Institute of Petroleum Exploration and Development, Chengdu, Sichuan 610094, China

近年来油气勘探揭示了川西前陆北段油气资源的巨大潜力，但因受控于龙门山—川西前陆系统多期构造活动和山前带深埋藏等，川西前陆山前隐伏构造带含油气构造模型解释具有明显的多解性和不确定性。基于川西北前陆原型与实验室砂箱构造物理模型间几何学—运动学—动力学相似性原理，通过两组川西前陆北段扩展变形构造物理模型对比实验（即标准模型实验和断坪—断坡模型实验），揭示川西冲断褶皱带—前陆盆地受控于中、下三叠统膏盐和下寒武统泥岩2套主滑脱层系，晚中生代—新生代呈现出分层式前陆扩展变形特征，基底断坪—断坡结构对川西北前陆深层冲断—冲起构造的控制影响作用最为明显。进一步结合川西北前陆双鱼石地区三维地震解释资料，揭示川西北前展式扩展晚期变形的古生界隐伏冲断—冲起构造构成了川西北深层主要的勘探潜力区。

Recent explorations reveal a great potential for oil and gas resources in the northwestern Sichuan foreland basin. However, constrained by multi-phase tectonic activities of the Longmenshan-West Sichuan foreland system and the deep burial of the piedmont belt, there remain many uncertainties in the interpretation of petroleum structure models in the foreland concealed tectonic belt. Based on the geometry-kinematics-dynamic similarity theory between the foreland prototype of the northwestern Sichuan and the sandbox analogue model, two groups of controlled experiments were carried out (including standard scaled experiments and analogue experiments with a ramp-flat structure). The fold-thrust belt and foreland basin of the western Sichuan are controlled by two sets of main detachments of the Middle-Lower Triassic gypsum salt and the Lower Cambrian mudstone, leading the layered-style propagation to the foreland in the Late-Middle Cenozoic. The ramp-flat structure plays a profound influence on deep thrust and pop-up structures in the northwestern Sichuan foreland basin. Analogue results combined with seismic interpretation of the northwestern Sichuan illustrates that the main exploration potential may rely on the Paleozoic blind thrust and pop-up structures caused by the latest propagation to the northwestern Sichuan foreland basin.

国家自然科学基金项目 41572111;四川省自然科学基金项目 2017JQ025

https://doi.org/10.11781/sysydz2020061031