致密气田产能分区定量评价研究

Quantitative Evaluation of Productivity Zoning in Tight Gas Fields

致密气具有低压、低渗、非均质性强等特点,开发难度大,为经济有效地开发,往往采用先肥后瘦、滚动开发的策略开发,因此对致密气田进行产能分区十分必要。目前致密气田产能有利分区常用的方法是地质多因素定性分析和储能系数法。地质多因素分析法主观性强,只能做到定性分析;储能系数法虽然可以做到定量分析,但忽略了致密气储层渗透率的作用,仅能体现储层气的富集程度,无法真实反映产能。将储层渗透率纳入考虑,提出产能综合系数QI(Kh?S_g)的概念,建立产能综合系数与气井无阻流量的关系,以经济极限无阻为界限,提出产能评价标准,对致密气田进行产能分区,找出区块真正意义的可动用甜点,为气田井位部署提供有利指导。

Tight gas is difficult to develop due to the characteristics of low pressure,low permeabili-ty and strong heterogeneity.To develop tight gas field more economically and effectively,the strategy of rolling development is often adopted,which is fat first and lean later.Therefore,it is necessary to divide the production capacity of tight gas field.At present,geological multi factor qualitative analy-sis method and energy storage coefficient method are commonly used in productivity favorable zoning of tight gas field.The geological multi factor analysis method has strong subjectivity and can only do qualitative analysis;while the energy storage coefficient method can do quantitative analysis,but it ignores the effect of tight gas reservoir permeability,only reflects the enrichment degree of reservoir gas,and can’t truly reflect the productivity.Taking reservoir permeability into consideration,this paper puts forward the concept of comprehensive productivity coefficient QI(KhϕSg),establishes the relationship between comprehensive productivity coefficient and open flow rate of gas well;based on economic limit open flow rate,productivity evaluation standard is put forward to divide tight gas field into production zones,and find out the real meaning of available desserts.The study provides favorable guidance for gas field well location deployment.