核磁共振录井技术在稠油领域的应用

Application of NMR mud logging in the viscous field

核磁共振录井技术应用于钻井过程中的油气评价虽然仅有几年的时间,但在发现与评价油气层方面已发挥了重要作用,然而随着该项技术的逐步深入应用,发现对于稠油储集层的解释评价符合率低。从这一角度出发,阐述了由于稠油比稀油的弛豫时间短、核磁共振信号弱,使该技术用于稠油储集层时显现出一定的不适应性,分析了稠油储集层核磁共振录井的影响因素。在此基础上,给出了稠油储集层孔隙度的修正系数,推导出稠油储集层渗透率的计算公式,并结合应用情况对其准确性进行了系统分析,归纳出识别不同稠油储集层的t2谱图特征。实际应用结果表明,该方法相对准确、可靠,有推广应用价值。

Though NMR mud logging technology has been used for oil and gas evaluation in drilling for only a few years,it plays an important role during discovering and evaluating reservoir.However,with the further application of the technology gradually,the interpretation and evaluation coincidence rate for viscous reservoir is found to be low and the un-adaptability has been shown.Setting out from this point,the author analyzes the affecting factors of NMR logging in viscous reservoir;states that the short relaxation time of viscous oil and the weak signal compared with dilution oil makes the analyzing method show a certain un-adaptability to viscous reservoir.On this basis,the modifying coefficient for viscous reservoir porosity is given,the computation formula for viscous reservoir permeability is derived,systematical analysis for its accuracy was carried out with combining with the application condition,and t2 spectra characteristics for distinguishing different viscous reservoir is given.It is showed by the application that the method is relatively accurate,reliable and has expanding and applying value.