苏里格气田致密砂岩气水相渗曲线特征与分类

Characteristics and classification of gas-water relative permeability curves of tight sandstone reservoirs in Sulige Gas Field

为解决苏里格气田致密砂岩气水相渗曲线指导气井产液调整的实际问题,对致密砂岩气水相渗曲线进行详尽分析,提出了符合气井分类的量化气水相渗曲线分类方案。苏里格地区盒8、山1段共83块岩样非稳态法气驱水相渗实验结果表明,致密砂岩气水相渗曲线具有束缚水饱和度S_(wi)、残余气饱和度S_(gr)和等渗点含水饱和度Sx较大,束缚水饱和度下气相相对渗透率K_(rg)(S_(wi))、残余气饱和度下水相相对渗透率K_(rw)(S_(gr))、等渗点相对渗透率K_(rx)(S_x)和气水两相共渗区面积S较小的特征,属于水相优势型相渗曲线。最终提出了以储层渗透率K、特征点参数K_(rg)(S_(wi))、K_(rw)(S_(gr))和K_(rx)(S_x)以及曲线特征为依据的气井量化分类方案,将致密砂岩气水相渗曲线分为Ⅰ—Ⅲ类,分类结果与气井类型一一对应,总体符合率达到89.7%。

In order to use gas-water relative permeability curves to guide the water production of the gas wells in Sulige Gas Field,it is necessary to classify the gas-water relative permeability curves of the gas wells. The unsteady-state gas driving water experiment results of 83 tight sandstone samples from He-8 member and Shan-1 member in Sulige area show that,the gas-water relative permeability curves of the tight sandstone samples have the characteristics as follows: the values of the irreducible water saturation( Swi),the residual gas saturation( S_(gr)) and the water saturation of isotonic point( S_x) are great,the values of the relative permeability of gas phase under irreducible water saturation( Krg( S_(wi)),the relative permeability of water phase under residual gas saturation( K_(rw)( S_(gr)),the relative permeability of isotonic point Krx( S_x)) and the gas-water common infiltration area( S) are small,and there is a kind of special water phase competitively relative permeability curve. Finally,a quantitative classification scheme of the gas-water relative permeability curves based on the permeability K,the feature parameters Krg( Swi),Krw( S_(gr)) and Krx( S_x),and the curve characteristics is put forward. According to the classification scheme,the gas-water relative permeability curves are classified into three types. There is one-to-one relationship between the types of the gas-water relative permeability curves are the types of gas wells,and their overall compliance rate reaches to 89. 7%. This classification scheme broadens the application of relative permeability curves and has important guiding significance to the actual production.