应用毛细管压力资料确定储层含水饱和度上限

DETERMINATION OF UPPER LIMIT OF RESERVOIR WATER SATURATION WITH CAPILLARY PRESSURE DATA

储层有效厚度物性下限包括孔隙度下限、渗透率下限和含水饱和度上限,只要能建立含水饱和度与孔隙度或渗透率之间的相关数学模型并准确确定前者,则后两者即可确定。为此,将不同地区具有不同油气藏物性下限值的岩心作为样品,采用经典的高压半渗透隔板仪实测气(油)水毛细管压力资料并由此确定储层含水饱和度上限。应用该方法所确定的CNT气田T3x2气藏、WDS气田P1x8气藏、CCG气田T3x4气藏和CNG油气田J2s油藏致密砂岩储层的含水饱和度上限分别是55%、50%、55%、50%。上述含水饱和度上限值已经过生产证实,理论计算结果和实际生产情况吻合较好。该参数已应用于相应油气藏的油气探明地质储量计算,并获得了全国矿产储量委员会的批准。

Lower limits of physical properties of net pay include lower limits of porosity and permeability and upper limit of water saturation.Provided that relational expressions between water saturation and porosity or permeability are established and the water saturation is accurately determined,the porosity or permeability can be calculated.Core samples with different lower limits of physical properties are collected from different areas,and the typical high pressure semi-permeable baffle plate is used to measure capillary pressures of gas/oil and water,which in turn are used to calculate the upper limit of reservoir water saturation.The upper limits of water saturation calculated with this method for the T3x2 tight sand gas reservoir in CNT gas field,the P2x8 tight sand gas reservoir in WDS gas field,the T3x4 tight sand gas reservoir in CCG gas field and the J2s tight sand oil reservoir in CNG field are 55%,50%,55% and 50% respectively.These upper limits of water saturation have been proved by production data and the theoretical calculation results are in good accord with the measured values.This parameter has been successfully applied to estimation of the proved reserves and ratified by China National Committee of Mineral Reserves.