基于总水平导数改进的密度界面快速反演方法  

Fast density interface inversion accelerated by the total horizontal derivative of gravity anomaly

作　　者：冯旭亮 王建峰 丁熙 王国华 FENG XuLiang;WANG JianFeng;DING Xi;WANG GuoHua(Shaanxi Key Laboratory of Petroleum Accumulation Geology,School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Changqing Oilfield Company No.2 Gas Production Plant,Yulin 719000,China;Changqing Oilfield Company No.3 Gas Production Plant,Wushenqi 017300,China)

机构地区：[1]西安石油大学陕西省油气成藏地质学重点实验室,西安石油大学地球科学与工程学院,西安710065 [2]长庆油田分公司第二采气厂,榆林719000 [3]长庆油田分公司第三采气厂,乌审旗017300

出　　处：《地球物理学进展》2021年第3期877-886,共10页Progress in Geophysics

基　　金：国家自然科学基金项目(41904115)资助。

摘　　要：直接迭代法是利用重力异常反演密度界面的一种重要方法,对迭代公式分析的结果表明,可在反演公式中添加加速收敛因子以减少反演的迭代次数从而提高效率.对于平缓的密度界面采用较小的加速收敛因子、而对起伏较大的界面采用较大的加速收敛因子可有效减少反演迭代次数.为此,本文利用重力异常总水平导数判断待反演界面起伏平缓和起伏较大的区域,并以此为基础,将总水平导数计算结果归一化至1.4~2.2之间而形成全区变化的加速收敛因子.假设待反演密度界面上下的密度差沿横向变化,将加速收敛因子加入迭代公式中形成最终的反演迭代公式.模型试算结果证实了本文方法可有效减少直接迭代法的迭代次数,并且也适用于含噪重力数据反演.最后将该方法用于渭河盆地西安凹陷的实际资料处理之中,反演结果证实了该方法的实用性.The direct iteration method is a critical approach to estimating the density interface relief with gravity anomaly.We consider that an Accelerating Convergence Factor(ACF)can be added to the inversion formula to reduce the number of iterations of the inversion and improve its efficiency after analyzing the iteration formula.A smaller value of ACF is recommended for the relatively flat density interface while a larger value of ACF is preferred for a rather fluctuant interface,which can effectively reduce the number of inversion iterations.The Total Horizontal Derivative(THDR)of gravity anomaly is used to recognize the flat region or rather fluctuant region of the density interface to be inverted,and then the THDR is normalized to between 1.4 and 2.2 to obtain the variable ACF in the whole region.The ACF is added to the iterative formula to form the ultimate iterative formula for inversion assuming that the density contrast of the target density interface changes laterally.Tests conducted with synthetic data confirm the correctness and stability of the proposed method,which can effectively reduce the number of iterations of the direct iteration method,and is also suitable for the noisy gravity data inversion.Finally,our proposed method is applied to the real data of xi’an sag in Weihe basin,and the results prove the practicability of the method.

关 键 词：密度界面 重力异常 加速收敛因子 总水平导数 

分 类 号：P312[天文地球—固体地球物理学] P315[天文地球—地球物理学]