陕北某气田井筒堵塞原因分析

Cause analysis of wellbore blockage in a gas field in Northern Shaanxi

陕北某气田井筒存在腐蚀和结垢,导致井筒堵塞严重。选取22口典型堵塞井为研究对象,通过堵塞因素与日均减产量之间的灰关联分析井筒堵塞主要影响因素,同时基于主成分分析对气井影响因素进行降维处理,并研究与井筒堵塞之间的关系。结果表明,引起陕北某气田井筒堵塞的原因主要有井筒腐蚀、CaCO_(3)结垢和气井出砂;引起气井堵塞的主要原因排序为:pH值>日均产水量>压差>CO_(2)含量;基于主成分分析,将影响气井堵塞的因素综合为六个因素,其中生产制度和阴离子含量对井筒堵塞影响明显;pH值、CO_(2)含量和压降协同作用是引起陕北某气田井筒腐蚀堵塞和结垢堵塞的主要原因。

Corrosion and scaling exist in the wellbore of a gas field in Northern Shaanxi,resulting in a serious wellbore blockage.Therefore,22 typical plugging wells were selected as the research objects,and the main influencing factors of wellbore blockage were analyzed through the grey correlation between plugging factors and daily average production reduction.At the same time,the influencing factors of gas wells were reduced based on principal component analysis,and the relationship between wellbore blockage and wellbore blockage was studied.The results show that the main causes of wellbore plugging in a gas field in Northern Shaanxi are wellbore corrosion,calcium carbonate scaling and sand production.The main causes of gas well blockage are as follows:pH>daily average water production>differential pressure>CO_(2)content.Based on principal component analysis,the factors affecting gas well plugging are integrated into six factors,in which production system and anion content have obvious effects on wellbore plugging.The synergistic effect of pH,CO_(2)content and pressure drop are the main causes of wellbore corrosion blockage and scaling blockage in a gas field in Northern Shaanxi.