新疆准噶尔盆地西北缘三维地震构造分析及其变形恢复

The Junggar Basin is located between the Altai Mountains and the Tianshan Mountains in central Asia. Surrounding the Junggar Basin, strike-slip faults, developed as a result of the N-S compression, plays an important role in accommodating the deformation of central Asia. Based on high-resolution 3D seismic reflection data, this research will investigate the 3D fault architecture of NW Junggar Basin quantitatively and propose a more effective workflow for 3D seismic interpretation. This research will be put into practice in three aspects: (a) investigate the deformation behavior of NW Junggar Basin by constructing 3D models of restraining bend, horsetail splay and arcuate splay; (b) identify the deformation timing of NW Junggar Basin by analyzing 3D morphology of unconformities and growth strata, in order to constrain and restore the structural evolution history since Late Paleozoic; (c) reveal the structural dynamics of NW Jung-gar Basin by 3D structural restoration and predict the geological setting since Late Paleozoic. The outcomes of this research will enrich the understanding on the tectonic deformation of central Asia. This research can also promote the transition from conventional structural analysis to high-resolution 3D seismic investigation, which is critical to the hydrocarbon exploration in NW Junggar Basin.

中亚内陆准噶尔盆地介于阿尔泰-天山山脉之间，在南北向挤压应力背景下盆地周缘发育走滑断裂，为协调中亚内陆变形扮演极其重要的角色。本研究基于高精度三维地震反射数据，研究准噶尔盆地西北缘断裂三维结构，实现复杂断裂构造解释的定量化和精细化，探索三维地震构造解释思路和技术方法。申请人拟开展三项工作：①通过三维地震刻画断裂褶皱几何形态，建立准噶尔盆地西北缘挤压构造结、马尾状挤压断裂带三维构造模型，厘定准噶尔盆地西北缘构造变形方式和规律；②研究构造不整合面、生长地层三维形态，厘定准噶尔盆地西北缘构造变形时间，约束和复原晚古生代以来构造演化历史；③通过三维变形恢复，探讨准噶尔盆地西北缘构造动力学机制，预测晚古生代以来构造变形的地质背景。研究成果有助于完善中亚内陆山脉-盆地构造变形认识，促进构造研究向三维地震转化，对准噶尔盆地西北缘油气勘探具有重要意义。

中亚内陆准噶尔盆地介于阿尔泰-天山山脉之间，盆地周缘断裂在中亚内陆变形过程起到重要作用。本项研究基于二维-三维地震反射剖面和油气钻探资料，开展准噶尔盆地西北缘-南缘构造几何学和运动学定量分析，测量构造变形参数：断层褶皱缩短量、断层运动方式、构造生长地层分布，建立断裂褶皱构造模型和变形序列。采用构造剖面平衡恢复和正演模拟技术方法，模拟构造变形过程，检验和修改构造解释模型，确定断层褶皱变形机制。准噶尔盆地西北缘晚二叠纪-三叠纪发育右旋走滑断裂，断裂延伸300公里，断裂南端发育挤压构造结，中段是高陡直立断层，北端是马尾状逆冲断裂尾端。断层侧翼雁行排列褶皱缩短量1-2公里，没有发现地层逆掩重复，表明准噶尔盆地西北缘发育走滑断裂，断裂挤压分量很小。准噶尔盆地南缘新生代发育逆冲推覆构造，南缘东段构造缩短量23 km，山前发育构造楔，缩短量20 km，盆地发育一排褶皱，缩短量1-2 km，山前构造楔吸收几乎所有断层位移量。南缘西段构造缩短量20-15km，山前构造楔缩短量10-12 km，盆地发育二排褶皱，缩短量7-9 km，断层位移量被山前构造楔和盆地褶皱分别吸收。准噶尔盆地南缘新生代变形分为二期，早期变形发生在山前，变形始于古近纪，晚期变形引发盆地褶皱，变形发生在第四纪。本项研究探索构造定量分析理论和方法思路，采用构造剖面平衡恢复和正演模拟技术，研究准噶尔盆地周缘断裂变形机理，不仅有助于提高中亚内陆山脉-盆地构造研究认识，对准噶尔盆地油气勘探和天山北麓地震活动研究具有重要意义。