龙岗地区储层微观鲕粒模型气水两相渗流可视化实验及分析

A visualized experiment on gas-water two-phase seepage through oolitic reservoirs in the Longgang Gas Field,Sichuan Basin

为了研究气水两相渗流在鲕粒灰岩中形成封闭气和残余水的机理,选取以四川盆地龙岗地区储层铸体薄片为模板制作的激光刻蚀微观鲕粒模型,进行了气水两相驱替实验。实验过程用高清数码相机对气驱水和水驱气现象进行拍摄和记录。对实验现象的分析结果表明:对于鲕粒模型,水驱气时卡断、绕流是形成封闭气的主要原因,盲端和不连通的孔隙也会形成封闭气;在气驱水时,细长孔道、狭窄喉道处以及卡断都有可能形成残余水。这些现象及其机理分析对于以鲕粒灰岩为主的气藏开发具有一定的参考价值。

In order to study the mechanism of the formation of confined gas and residual water when gas-water two-phase fluids flow through the oolitic limestone,we selected the casting sheet image of reservoirs in the Longgang Field of the Sichuan Basin as the template for making a microscopic oolitic model by pulse laser ablation.With this model,the experiment on gas-water two-phase displacement was performed and the whole process was shot and recorded by a high-definition digital camera especially including the phenomena of gas-driven water and water-driven gas.Through the analysis of this experiment,it is concluded that jamming or detouring in the water-driven gas is the main reason for the formation of confined gas,which also occurs in the dead end and unconnected pores;while jamming is one of reasons for the formation of residual water,which may be formed in the slim and long pore channels or narrow pore throats.