江汉盆地潜江凹陷潜江组非砂岩储层改造实验

IMPROVEMENT EXPERIMENT OF NONSANDSTONE RESERVOIRS OF QIANJIANG FORMATION IN THE QIANJIANG SAG,THE JIANGHAN BASIN

组成江汉盆地潜江凹陷潜江组盐间段非砂岩储层的岩石主要为泥晶白云岩、钙芒硝岩、泥岩及其混积岩,孔渗性普遍较差。实验选用饱和盐水、饱和盐水+醋酸及饱和盐水+醋酸+盐酸等3种不同溶液,对王云10—6井潜二段的4号样(含钙芒硝泥晶白云岩)和王平1井潜三段的8号样(含云细—中晶钙芒硝岩)进行处理。由毛管压力曲线分析可知,处理后的岩样排驱压力明显减小,4号岩样降幅达62%,8号岩样达88%;最大孔喉半径显著增加,4号和8号岩样的增幅分别为187%和743%,孔喉分选系数得到明显提高;2个岩样的孔隙度分别增加了1倍多。实验结果表明,处理后的岩样骨架保持完好,孔渗性得到了有效改善。

Nonsandstone reservoirs between salt beds of Qianjiang Formation in the Qianjiang Sag of the Jianghan Basin are mainly composed of dolomicrite,glauberite rock,mudstone and their peperite.Porosity and permeability are commonly poor.In the experiment,sample No.4 of Member 2 of Qianjiang Formation in Well Wangyun 10-6(glauberite-bearing dolomicrite) and sample No.8 of Member 3 of Qianjiang Formation in Well Wangping 1(dolomite-bearing fine-medium crystalline glauberite) are processed with 3 different solutions: saturated saline water,mixture of saturated saline water and acetic acid,and mixture of saturated saline water,acetic acid and hydrochloric acid.Capillary pressure curves indicate that,expulsion pressures of the processed samples No.4 and No.8 decrease by 62% and 88% respectively.Maximum pore-throat radiuses increase by 187% and 743% respectively.There is obvious improvement in sorting coefficient of pore-throat too.In addition,porosities of both samples increase by over 100%.The experiment shows that,skeleton of the processed samples maintains intact,while porosity and permeability are improved effectively.