对r_(35)经典产能评价指标的探讨

A discussion on the classic productivity-evaluation index of r_(35)

对东海XH凹陷410块岩样压汞资料确定的r35与岩心常规物性K/的关系进行了统计,发现不同孔隙结构特征的岩样具有不同统计关系式,与Aguilera等确定的r35经典关系式存在较大差异。对该区域取心和地层测试兼具的7口井13层资料进行了分析,发现常规气与致密气储层的r35分界值在0.60μm左右,与Byrnes等确定的0.50μm存在一定差别,这与基础数据来源不同有关,因为东海XH凹陷气藏属三角洲沉积或潮坪沉积,而Roberto等的r35图版是在北美等国外海相地层数据基础上建立的。在采用r35评价某区域气藏产能时,须谨慎引用经典技术指标,应首先立足本区域基础资料建立r35评价技术指标。

In XH sag, East China Sea, the mercury injection data of the existing 410 rock samples were used to determine r_35 , and its statistical relationship with the conventional petrophysical parameter K/φ of cores was researched, by which it was found that there were various statistical relationships for the samples with various pore structure, quite different from the classic r_35 formula identified by Aguilera et al. By analyzing 13 interval data in 7 wells with both coring and formation testing, it was found that a boundary value be- tween conventional gas and tight gas reservoirs was at around 0.60μm, quite different from 0.50 μm iden- tified by Byrnes et al. This may resulted from the different basic data, with the gas reservoirs in XH sag being delta or tidal-flat facies, and the chart from Roberto et al being on a basis of marine facies in North America and other foreign country. Therefore, the classic index should be cited with caution when using r_35 to evaluate gas reservoir productivity, and it should be given priority to establish r_35 evaluation index by using the basic data in a study area.