滇黔北地区地层压实恢复及沉积速率反演

为了恢复滇黔北地区地层压实过程并进行沉积速率反演，将优化模型与传统方法相结合，建立了滇黔北地区分层声波时差和孔隙度随深度变化的模型，而后基于岩石骨架不变原理对该区地层进行分层回剥，获得了上奥陶统五峰组至第四系较完整的地层原始沉积厚度和各组地层分段沉积速率，并探讨了页岩地层沉积速率与有机质丰度的关系。结果表明：滇黔北地区地层沉积速率总体较低，早期沉积速率升高并达到峰值，随着地层年代由老变新，沉积速率骤降而后再缓慢升高，随后再次降低直至该区沉积速率的最低值，其中志留系龙马溪组和罗惹坪组 2 套主要页岩地层的沉积速率分别为 77.97 m/Ma和 113.47 m/Ma；陆棚环境下较缓慢的沉积速率有助于提高页岩有机质丰度。研究成果可为该区地层埋藏演化史研究和页岩气勘探开发提供一定的参考。

Restoration of formation compaction and inversion of deposition rate in Dianqianbei exploration area

The Dianqianbei exploration area is a potential shale gas development zone, located in the southern margin of the Sichuan Basin. In order to identify the restoration of formation compaction and inversion of deposition rate, this paper established the Upper Ordovician to Quaternary model of layered acoustic and porosity with depth by using optimization models combined with the traditional methods, then carried out layered back ripping based on the principle of rock skeleton unchanged, acquired the original formation sedimentary thickness and segmented deposition rate, and discussed the relationship between the deposition rate and the abundance of organic matter of shale formation. The results show that the deposition rate is lower and tow?wave like in Dianqianbei area. It increased rapidly to its peak and dropped in early period, then climbed up slowly and downed to valley in later period. The deposition rates of Silurian Longmaxi Formation and Loureping Formation are 77.97 m/Ma and 113.47 m/Ma respectively. The shelf environment with slow deposition rate is beneficial to enhance the organic matter abundance of shale. The results are references for researching stratigraphic burial evolution and shale gas exploration and development.