对水平井油气层保护技术的探讨

在水平井钻井与完井过程中，由于水平井段易形成岩屑床，油气层受钻井液，完井液的浸泡时间长等原因，水平井油气层损害已成为影响其产能发挥的一个重要问题，从分析造成水平井油气层损害的主要因素出发，提出了减少水平井油气层损害的措施和技术，同时通过建立相应的理论分析模型并进行求解，分析计算了影响水平井产能的各种因素，分析对比了水平井与垂直井的产量降低幅度。分析结果表明：（１）油气层损害是影响水平井产能的一个重

AN APPROACH TO FORMATION DAMAGE CONTROL, IN HORIZONTAL, WELLS

Formation damage, during drilling and completion of horizontal wells, has been a serious problem which affects the production capacity of pay zones in horizontal wells, because of cutting's bed forming on bottom side of horizontal wells and drilling and well completion fluids invading into formation. This paper presents an analysis of the main factors of influencing formation damage in horzontal wells, introducing the particular techniques to prevent or release the damage. A mathematical model was established to calculate and compare the damage degree between horizontal and vertical wells. Analysis results show that: (1) formation damage is an important reason affecting the production capacity of horizontal wells; (2) the damage zone, caused by drilling and well completion fluids invasion, made a more serious damage in horizontal wells than in vertical wells ; (3) in general, the sensitivity to formation damage in horizontal wells are Iess than that in vertical wells, nevertheless, once the horizontal well is damaged, the production capacity of the horizontal well will decline obviously and it is hard to treat. The paper also discussed the techniques to prevent the formations in horizontal wells from damage.