致密砂岩气藏地层水可动性及其影响因素研究

Formation Water Mobility and Influencing Factors in Tight Sandstone Gas Reservoir

为研究致密砂岩气藏储层物性参数与地层水可动能力间的关系,明确不同物性储层的地层水可动性,通过核磁共振方法测量岩心孔隙大小分布,进行了X射线全岩衍射分析,提出了一种采用离心法与核磁共振相结合方式划分地层水可动程度的新方法,并分析了孔隙度、渗透率、孔隙结构、岩石矿物组成与地层水可动性之间的关系。结果表明,地层水可动或不可动无绝对界限,储层孔隙结构决定地层水可动性;矿物组成对地层水可动性影响不大。研究认为,地层水根据可动性可分为束缚水、可动束缚水、可动水,但束缚水饱和度、可动束缚水饱和度、可动水饱和度的划分不是绝对的,通过实验方法可得到其近似值。研究结果对致密砂岩气藏划分开发层系,减小地层产水可能性具有指导意义。

Nuclear magnetic resonance was used to test core pore size distribution and whole-rock X-ray diffraction analysis was conducted to understanding the relationship between physical properties and formation water mobility and determine the formation water mobilities under different physical properties in tight sandstone gas reservoir.A new method for formation water mobility classification by combining with centrifugalizing and nuclear magnetic resonance was proposed to analyze the relationship between porosity,permeability,pore structure,rock mineral composition and formation water mobility.Result indicates that there is no absolute limit for the movable or immovable water,and the formation water mobility is greatly dependent on the reservoir pore structure.Mineral composition shows little effect on the formation water mobility.It is believed that the formation water can be classified into bound water,movable bound water and movable water,while there is no absolute limit for the classification of bound water saturation,movable bound water saturation and movable water saturation.The corresponding approximate values can be gained through laboratory experiment test.This research could provide certain guidance for the tight sandstone gas reservoir development and reduction of formation water production risk.