海上油田脉冲中子–中子测井蒙特卡罗方法模拟研究

Monte Carlo Simulation Result of Pulsed Neutron-neutron Logging Method for Offshore Oilfield

摘要: 脉冲中子–中子(PNN)测井受管柱、地层物性和地层流体等诸多因素的影响，无法准确提取测量到的地层宏观俘获截面，从而影响剩余油饱和度的计算。根据海上油田的实际生产情况，针对其复杂的管柱结构、更大的地层水矿化度变化范围、泥质含量以及孔隙度等因素，基于蒙特卡罗方法进行了相应的数值模拟。通过对各因素模拟的响应结果分析，在三层管柱、泥质含量高于20%的条件下时仪器测量精度不高，为了更加准确地提取地层宏观俘获截面，通过分析研究给出了取道建议，为精细评价地层剩余油饱和度提供一定的理论依据。

Abstract: PNN (pulse neutron neutron) logging would be affected by many factors such as casing string, formation physical properties and formation fluids, which would lead to the inability of accurate extraction of the measured macro-capture section of the formation, thus affecting the calculation of remaining oil saturation. In this paper, based on the actual production situation of offshore oilfield, the corresponding numerical simulation was carried out based on MCNP (Monte Carlo method) for the complicated string structure, formation water salinity, shale content and porosity with a wider range of variation. Through the response analysis of each factor simulation, when it is in the third casing string, the shale content is higher than 20%, the measurement accuracy is not high. For more accurately extracting the macro-capture section of the formation, some suggestions are given for channel selection, which provides a certain theoretical basis for the fine evaluation of remaining oil saturation of the formation.