致密砂岩储层具有较强的非均质性,用常规方法难以实现对其渗透率的有效预测。为了解决该问题,同时考虑岩石电导率、颗粒电导率、地层水电导率及胶结指数等建立了致密砂岩储层渗透率模型,并通过对致密砂岩渗透率的数值分析,探讨了这些因素对致密砂岩渗透率的影响,建立了相关解释图版。研究表明:①致密砂岩渗透率随着岩石电导率的增大而增大。当岩石电导率较小时,其对渗透率的影响较小;反之,影响较大。②致密砂岩渗透率随着颗粒电导率的增大而减小,但颗粒电导率对致密砂岩渗透率的影响并不大。与颗粒电导率相比,岩石电导率对致密砂岩渗透率的影响更大。③致密砂岩渗透率随着胶结指数的增大而增大。当胶结指数较小时,其对致密砂岩渗透率的影响较小;反之,影响较大。将该方法应用于川西地区三叠系致密砂岩储层渗透率的预测,取得了较好的应用效果,证明了该方法的有效性。研究成果对致密砂岩储层评价及测井评价等均具有一定的参考价值。
The tight sandstone reservoirs have strong heterogeneity, and it is difficult to realize effective prediction of permeability by conventional methods. In order to solve this problem, this paper established a permeability model for tight sandstone reservoirs considering rock conductivity (Cs), grain conductivity (Cg), formation water conductivity (Cw)and cementation index (m), then discussed their effects on permeability, and established the relevant interpretation chart in the reasonable value selection range. The results show that: (1) With the increase of Cs, the permeability of tight sand-stone increases. When the Cs of rock is lower, its effect on permeability is less; otherwise, the effect is greater. (2) With the increase of Cg, the permeability of tight sandstone decreases, but the effect of Cg on permeability of tight sandstone is not great. Comparing with Cg, the effect of Cs on permeability of tight sandstone is greater. (3)With the increase of m,the permeability of tight sandstone increases. When the m is lower, its effect on permeability is less; otherwise, the effect is greater. This method was applied to predict the permeability of the Triassic tight sandstone reservoirs in western Sichuan Basin, and a good application effect has been achieved. This research could provide important reference for tight sandstone reservoir evaluation and logging interpretation.