非平行界面地层水平井自然伽马测井蒙特卡罗模拟

Monte Carlo Simulation of Natural Gamma Logging in Horizontal Wells with Non-parallel Interfaces

在水平井随钻测井地质导向工作中,地层上下界面往往不是理想的平行状态,继续沿用以往平行界面地层模型的认识将影响此类地层中的地质导向效果。为此,基于蒙特卡罗方法,建立水平井非平行界面地层模型;利用模型正演研究了非平行界面不同夹角、层厚和仪器偏心情况下非平行界面地层模型中的自然伽马测井响应特征。结果表明,在所探讨的不同地质条件下地层界面倾斜均会对自然伽马测井造成一定程度的影响,且界面倾角越大影响越严重。研究结果可为非平行界面地层下实时地质导向和测井解释校正工作提供参考和借鉴。

In the geosteering work of logging while drilling in horizontal wells,the upper and lower interfaces of the formation are often not in an ideal parallel state.Continuing to use the previous un-derstanding of the formation model with parallel interfaces will affect the geosteering effect in such formations.For this reason,based on the Monte Carlo method,the author establishes the formation model of non-parallel interface in horizontal wells;The response characteristics of natural gamma logging in the non-parallel interface formation model with dfferent angles,layer thickness and tool eccentricity were studied by using model forward modeling.The results showed that under the differ-ent geological conditions discussed,the formation interface dip would have a certain degree of impact on natural gamma logging,and the greater the interface dip,the more serious the impact.The re-search results can provide reference and reference for real-time geosteering and logging interpretation and correction under non-parallel interface formation.