粉细砂岩油藏防砂井堵塞规律研究及充填参优化

Sand Blocking Mechanisms and Sand Control Parameters Optimization Design in Fine Siltstone Reservoirs

粉细砂岩油藏的纵向层系较多,层间矛盾严重,出砂堵塞影响提液生产效果。在现有斜直井产能模型的基础上,对筛管、环空充填层、挤压充填层和储层的渗透率细化描述,改进了机械防砂表皮系数公式。通过室内实验分析了防砂体系堵塞规律,认为随着驱替注入量和驱替流量提高,防砂体系堵塞加剧,渗透率最大下降40%。储层颗粒进入套管内,堵塞环空砾石与防砂筛管,导致表皮系数急剧上升,产能下降超过80%。扩大挤压充填半径能够将微粒阻挡在远离井眼的位置,有助于保持油井产能。对分层防砂井充填半径进行优化分析,发现在中低渗透扩大充填半径能够改善层间动用效果。对盘二沙三下区块的防砂井充填参数优化,对渗透率较低的S4层扩大充填半径,措施后油井液量保持稳定,日产油提高9.56t。

The siltstone reservoir has many vertical small layers.Well productivity is affected by sand blocking.Based on the existing productivity model of inclined vertical well,the permeability of screen pipe,annulus filling layer,squeeze filling layer and reservoir are described in detail,and the formula of skin coefficient of mechanical sand control is improved.The blocking law of sand control system is analyzed through laboratory experiments.It is considered that with the increase of displacement volume number and displacement flow,the plugging of sand control system intensifies and the maximum permeability decreases by 40%.Reservoir particles enter the casing and block the annulus gravel and sand control screen,resulting in a sharp increase in skin factor and a decrease in production capacity of more than 80%.Expanding the squeeze packing radius can block particles away from the wellb ore and help to maintain oil well productivity.Through the optimization analysis of the filling radius of layered sand control wells,it is found that expanding the filling radius in medium and low permeability can improve the interlayer production effect.The filling parameters of sand control wells in typical blocks are optimized,and the filling radius of S4 layer with low permeability is expanded.With the measures,the oil well fluid volume remains stable,and the daily oil production increases by 9.56 t.