时频电磁(TFEM)技术：数据联合约束反演

在油气勘探中，时频电磁（TFEM）数据反演可以利用更多的已知资料。充分利用已知资料有效减小反演非唯一性具有重要意义。建立联合反演目标函数，采用人工鱼群算法实现TFEM勘探水平电场和垂直磁场的联合约束反演；设计层厚度、电阻率和极化率等参数三类模型空间，以实现对不同层位参数的灵活约束，给出了模型参数空间设置的方法和规则，能够充分利用或多或少的已知资料对反演参数进行约束；同时提出了三类模型的分步反演方案，其中一些措施有效地减小了反演结果的非唯一性、提高了反演精度。模型测试和实际剖面反演表明，人工鱼群算法和分步约束的反演方案能够很好地克服反演的非唯一性并确保勘探精度和效果，有较强的实用性。

Time-frequency electromagnetic(TFEM) technique: step-by-step constraint inversion based on artificial fish swarm algorithm

In oil and gas exploration,time-frequency electromagnetic (TFEM) inversion can use more known data. It is of great significance to make full use of known data and effectively reduce the non-uniqueness of inversion. Based on the artificial fish swarm algorithm,we developed an objective function for TFEM inversion under joint constraints of horizontal electric field and vertical magnetic field,designed three kinds of model spaces including layer thickness,resistivity and polarization for suitably constraining horizon parameters,proposed the methods and rules for setting model space with the purpose of making full use of known data,and developed step-by-step constrained inversion schemes for three types of models. These measures effectively reduce the non-uniqueness of inversion and improve inversion accuracy. Model and real data tests have proved that the artificial fish swarm algorithm and step-by-step constrained inversion schemes can reduce the non-uniqueness and ensure exploration accuracy and effect,so it can be used widely.