随钻中子测井仪的蒙特卡罗模拟与优化方法  

Monte Carlo Simulation and Optimization Method of Neutron Logging Tool While Drilling

作　　者：李国梁 张钦中 李雨莲 张琼 陈红喜[1] 刘晓斌[1] LI Guoliang;ZHANG Qinzhong;LI Yulian;ZHANG Qiong;CHEN Hongxi;LIU Xiaobin(Well-Tech R&D Institute,China Oilfield Services Limited,Tianjin 300459,China;School of Automation Engineering,University of Electronic Science and Technology of China,Chengdu,Sichuan 611731,China)

机构地区：[1]中海油田服务股份有限公司油田技术研究院,天津300459 [2]电子科技大学自动化工程学院,四川成都611731

出　　处：《测井技术》2021年第4期357-362,共6页Well Logging Technology

摘　　要：随钻中子孔隙度测井在复杂地层条件评价中发挥着重要作用。利用蒙特卡罗方法建立地层模型,实现对随钻中子仪器的模拟和对仿真模型准确性的验证;应用减方差技术,在保证模拟结果准确性的同时提高模型运算效率。研究结果表明,通过对20口刻度井的模拟,2种随钻中子仪器INP675和INP800的模拟计数比值和实测计数比值的相关性分别为0.9746和0.9525,相对误差均小于4.5%,验证了仿真模型的准确性和可靠性,为模拟仪器在套管井中的测量响应提供了基础;应用平行几何体加速蒙特卡罗模拟后,计数比值的统计误差是原来的1/5,品质因子至少高于原仿真结果的50倍,有效提高了模拟效率,节约了成本。Neutron porosity logging while drilling plays an important role in formation evaluation under complex environment.The formation model is established by Monte Carlo method to simulate the neutron tool while drilling and verify the accuracy of the simulation model.The variance reduction method is applied to ensure the accuracy of simulation results and improve the computational efficiency The results show that:through the simulation of 20 calibration wells,the correlation between the simulated counting ratio and the measured counting ratio of INP675 and INP800 are 0.9746 and 0.9525 respectively.The relative error is less than 4.5%,which validates Monte Carlo simulation and provides the foundation for the measurement response simulation of the tool in cased wells.After using parallel geometry to accelerate Monte Carlo simulation,the statistical error of the count ratio is one fifth of the original,and the FOM(Figure of Merit)is at least 50 times of the original simulation results.The method effectively improves the simulation efficiency and saves the cost.

关 键 词：随钻中子孔隙度测井 蒙特卡罗方法 模拟 减方差 

分 类 号：P631.84[天文地球—地质矿产勘探]