西湖凹陷天然气井诱喷返排规律及主控因素研究

Study on Induced Flow and Flow-back Law and Main Control Factors of Natural Gas Wells in Xihu Sag

东海西湖凹陷以天然气井为主,气藏埋藏深度深,储层较为致密,容易受到钻完井液污染,如何快速清井诱喷对于改善气井初期投产效果非常重要。目前东海开发井投产诱喷方式复杂多样,各井投产效果不同,针对开发井诱喷规律的系统研究较少,亟需从多专业结合的角度进行开发井诱喷特征和影响因素分析,以期为今后诱喷作业提供建议。采用大数据统计分析方法对西湖凹陷8个主要产量贡献气田、57口开发井投产诱喷的规律和特征进行统计分析,梳理总结出影响诱喷效果的6个主控因素为储层孔隙度、渗透率、电阻率比值、钻井液类型、射孔工艺、返排工艺,并建立了开发井诱喷返排效果预测图版,为东海后期开发井诱喷工作制度优选、提高诱喷效果和降低作业成本提供了重要依据。

Xihu Sag in East China Sea is dominated by natural gas wells with deeply buried and tight reservoir,which is easy to be contaminated by drilling and completion fluids.In this case,how to quickly clean well and induce blowout is very important to improve the effect of initial production of gas well.At present,the methods of induced flow are complex and diverse for development wells of the East China Sea,and the effects of each well are different.The systematic studies on the law of induced flow in development wells are few.Therefore,it is urgent to analyze the characteristics and influenc-ing factors of induced flow in development wells from the perspective of multi-professional combination,so as to provide suggestions for induced flow in the future.Using the method of big data statistical analysis,the law and characteristics of induced flow in 8 major production contributing gas fields and 57 development wells in Xihu Sag are analyzed statistically.Six main control factors of induced flow are summarized:reservoir porosity,permeability,resistivity ratio,drilling fluid type,perforation technology and flow-back technology.The prediction chart of flow-back effect is established,which provides an important basis for the optimization of flow-back work system,improvement of flow-back effect and reduction of operation cost in the later development.