【摘要】 计算密度分界面的起伏变化在区域地质构造研究和石油矿产资源勘探中具有重要意义.已有密度界面反演方法更多侧重约束变密度界面反演算法,而对约束信息的准确性、研究区横向密度变化往往考虑不足,影响了最终反演结果的可信度.本文在变密度界面正反演算法基础之上,结合实际需求,提出已知深度信息约束下的变密度界面反演策略.该策略主要包括变密度约束反演算法、已知深度约束信息校验和分区变密度模型三个方面.其中反演算法提供了带已知深度约束信息的密度界面迭代反演方法;约束信息校验用于评估约束信息精度,通过调差降低约束信息的系统误差;在反演过程中引入水平密度分区以应对不同构造背景密度界面模型,提高反演结果的可信度.最后将本策略应用于南海莫霍面深度反演计算中,结果显示借助已知约束信息,利用分区密度模型能够获得更为可信的深度反演结果,验证了该策略的正确性.更多还原

【Abstract】 Calculation of density interface using inversion of gravity data is of great significance in research of regional geological structure and mineral resources exploration. Existing inversion methods focus on the constrained varying density interface inversion algorithm, however, less considering accuracy of the constraint data and lateral density changes of targeted areas, thus affecting reliability of final inversion results. To solve this problem, based on the forward modeling and inversion algorithm of varying density interface and actual requirements, this paper proposes a density variable interface inversion method under the constraint of known depth information. It includes three aspects: algorithm of varying density constrained inversion, verification of known constraint information and partition of the density model. The algorithm provides an iterative inversion for density interface with known depth constraint information; verification of constraint information evaluates the accuracy of the constraint and reduces its systematic error; and horizontal density partitioning is introduced in the inversion to deal with density interface models of different structure backgrounds, and to improve the credibility of the results. The proposed method is applied to estimation of the Moho depth in the South China Sea. More reliable depth is obtained with known constraints and a partition density model, which proves effectiveness of the method suggested.更多还原