The fast modeling of gamma-gamma density well logging is essential for the inversion techniques of formation properties, which is usually carried out jointly with other logging measurements such as electrical logging. It also can help to adjust the initial geological model in real time during geosteering. The Monte Carlo method is the foremost numerical technique to simulate gamma-gamma density logging measurement. But due to its slow speed, it is not sufficient for inversion or real-time forward modeling. An algorithm to achieve the fast simulation of density logging response is introduced. In the algorithm, a new approximation model is proposed to enable accurate forward modeling of density logging with better efficiency. The Monte Carlo simulation method is utilized as a benchmark to validate the performance of the fast simulation method. The density logging responses under vertical and high-angle well conditions are simulated. The results of the fast simulation show a good agreement with the Monte Carlo simulations in vertical and high-angle wells. In addition, the comparison of density imaging data also confirmed the accuracy of the fast simulation method.

γ-γ密度测井的快速建模对于地层性质的反演技术至关重要，该技术通常与其他测井测量（例如电测井）一起进行。它还可以帮助在地质导向过程中实时调整初始地质模型。蒙特卡洛方法是模拟伽玛-伽玛密度测井测量的最重要的数值技术。但是由于速度慢，不足以进行反演或实时正向建模。介绍了一种实现密度测井响应快速仿真的算法。在该算法中，提出了一种新的近似模型，以实现密度测井的准确正向建模，并且效率更高。蒙特卡罗模拟方法被用作基准，以验证快速模拟方法的性能。模拟了垂直井和大角度井条件下的密度测井响应。快速模拟的结果与垂直和大角度井中的Monte Carlo模拟显示出良好的一致性。另外，密度成像数据的比较也证实了快速仿真方法的准确性。