延安气田天然气储层特征及增压开采技术研究

Study on characteristics of natural gas reservoir and pressurized exploitation technology in Yan′an Gas Field

针对延安气田天然气储层的特征及增压开采技术进行研究,从岩石学特征、孔隙类型及结构、成岩作用、物性特征4个方面分析天然气储层特征,再结合天然气开采现状,评估气井资源量。在合理选择气井位置的基础上,综合考虑气井最低生产压力和气田增压方式之间的关系,通过经济效益对比分析,作出最优的增压开采决策。测试结果表明,延安气田天然气储层的碎屑成分主要为石英、岩屑以及水云母等,白钛矿、高岭石等相对含量极少;孔隙结构孔喉较窄,排驱压力偏大,主要喉道贡献较低,分选情况不佳;中石英砂岩物性最佳,其孔隙度与渗透率较好。选择气井最低生产压力1.2 MPa、区域增压方式开采天然气,可实现开采经济效益最大化,并大幅度提升采收率。

In this paper,the characteristics of gas reservoir and pressurized exploitation technology of Yan′an Gas Field were studied.This paper analyzed the characteristics of natural gas reservoir from four aspects of petrology,pore type and structure,diagenesis and physical property,and then evaluated the resource amount of gas well in combination with the current situation of natural gas exploitation.On the basis of reasonable selection of gas well location and comprehensive consideration of the relationship between gas well minimum production pressure and gas field pressurization method,the optimal pressurized exploitation decision was made through comparative analysis of economic benefits.The results showed that the detrital components of gas reservoirs in Yan′an Gas Field were mainly quartz,lithic debris and hydromica,while the relative content of white titanium and kaolinite was very little.The pore structure was narrow,the displacement pressure was high,the contribution of main roar was low,and the sorting condition was not good.Medium quartz sandstone had the best physical properties,and its porosity and permeability were better.Selecting the minimum production pressure of 1.2 MPa and regional pressurization to extract natural gas could maximize the economic benefit of exploitation and greatly improve the recovery factor.