低孔低渗砂岩储层特征及岩石物理实验分析

随着石油勘探和开发程度的延伸,低孔渗油田储量所占的比例越来越大。低孔低渗储层压实程度高,成岩作用复杂,地质解释模型和测井解释模型拟合复杂。低孔低渗储层孔隙的形成和演化受成岩作用的控制,主要成岩作用有机械压实作用、胶结作用和溶蚀作用。压实作用、胶结作用不利于孔隙的演化,而溶蚀作用有利于次生孔隙的形成。从岩石物理实验的角度开展研究,分析了低孔低渗岩石地层因素与孔隙度、电阻增大率与含油饱和度的关系以及核磁共振横向驰豫(T_2谱)特性等。对低孔低渗砂岩与常规砂岩物性进行了对比分析。指出了低孔渗储层岩石物理特征的特殊性,为准确测井解释油气层提供了依据。

Characteristics and petrophysics experiment of low-porosity and low-permeability sandstone reservoir

With the extension of petroleum exploration and devel- opment,the proportion of low-porosity and low-permea- bility reservoir takes more and more advantageous position. The low-porosity and low-permeability sandstone reser- voir is of high compaction degree and of complicated diagene- sis.Therefore,it is hard to match the geologic interpretation model with the logging interpretation model.The study indi- cates that the formation and the evolution of its porosity are dominated by the diagenesis.And the diageneses mainly comprise the cementation,the compaction and the dissolu- tion.Among the diageneses,the cementation and the com- paction are unfavorable to the pore evolution,while the dis- solution is favorable to the formation of secondary pores.On the basis of petrophysics experiments,a study is performed on the relation of formation factors of the low-porosity and low-permeability sandstone reservoirs with porosity,re- sistance increase rate and oil saturation,and on the character of NMR (nuclear magnetic resonance)cross relaxation (T2 spectrum).Through contrast analysis on the low-porosity and low-permeability reservoir with regular one,the partic- ularity of the physical properties of the low-porosity and low-permeability reservoir is presented,which provides a scientific basis for obtaining accurate logging interpretation.