特低渗透砂砾岩储层核磁共振可动流体参数分析

 利用核磁共振技术，对乌里雅斯太油田腾格尔III油层组（TIII）及阿尔善油层组37块低渗透砂砾岩储层岩样进行可动流体测试，测试结果与常规砂岩储层进行对比，分析可动流体百分数与渗透率和驱油效率的关系。研究结果表明，特低渗透砂砾岩储层可动流体含量较低，非均质性强；特低渗透砂砾岩储层的核磁共振特点与常规特低渗透砂岩储层有所不同，表现为特低渗透砂砾岩储层核磁共振T2谱单峰结构增多，T2截止值增大；可动流体百分数与渗透率有一定的相关性，且渗透率越大，相关性越好；对于不同油层组，可动流体平均含量随渗透率增大而增加；可动流体百分数越大，驱油效率越高；可动流体含量低是特低渗透砂砾岩储层开发效果不好的主要因素，可用可动流体百分数预测储层的开发效果。

Analysis of NMR Moveable Fluid Parameters in Ultra-low Permeability Glutenite Reservoir

The movable fluid testing was carried out in 38 glutenite cores of ultra-low permeability reservoir using nuclear magnetic resonance technique. These cores are from Tenger III and Arxan formations of Uliastai Oilfield. Testing results were compared with cores of general sandstone reservoirs, and the correlations with the percentage parameter of moveable fluid and permeability and oil-displacement efficiency were analyzed. Ultra-low permeability glutenite reservoir is shown to have a low content of moveable fluid and strong heterogeneity. The characteristics of NMR are different in some extent from those of general ultra-low permeability sandstone reservoirs, with more mono peaks and a larger value of cutoff T2. The percentage parameter of moveable fluid is related to formation permeability to some degree, and the relation becomes better as the permeability increases. The average content of moveable fluid increases as the permeability increases for different formations. The oil-displacement efficiency becomes higher with increase of the percentage parameter of moveable fluid. Low content of moveable fluid is the major factor which negatively affects the exploitation of ultra-low permeability formation. The percentage parameter of moveable fluid can be used to predict the result of exploitation of ultra-low permeability formation.