定方位射孔对出砂的影响分析

Analysis of Oriented Perforation’s Impact on Sand Production

油气井开采过程中有的出砂问题十分严重。不仅会缩短油井的寿命、磨蚀地面及井下设备、造成桥堵或井眼堵塞,还会降低油井的产量严重时甚至会迫使油气井停产,严重影响了油田的正常生产。为保证油气井的开发进度及效果,必须控制出砂。出砂受到各种综合因素的影响,如何准确预测出砂并有效地加以预防是延长油气井生产年限和保证良好经济效益的关键所在。因此,有效地解决出砂问题是保证油气井开发效果的重要举措。定方位射孔沿着最大主应力方位进行射孔,从而避开了井筒内易出砂的方向,有效地防止出砂现象。由此可见,研究定方位射孔与出砂的关系有着十分重大的意义。分析了出砂的各种影响因素,以降低破裂压力和防止出砂为研究的出发点,开展定方位射孔对破裂压力和出砂的影响分析。通过对井下岩石和射孔孔道的应力分布的研究,建立井下破裂压力和出砂临界压差的计算模型。结论表明对于定方位射孔,最佳的射孔方位为沿着最大水平主应力方位。

The sand production so terrible when drilling and producing oil and gas wells that wells＇ service life would be shortened, surface and downhole equipments would be corrosived, and it results in bridge blinding, well clogging, reducing production even stopping production. So, sand production must be controlled so that the progress and effect of oil and gas wells＇ drilling and producing can be guaranteed. All the factors impacting on sand produc- tion are analyzed. The study is on the threshold of reducing the formation fracture pressure and preventing sand pro- duction. By developing the effect analysis of oriented perforation to the formation fracture pressure and sand produc- tion and conducting the stress distribution study of wellbore rocks and perforation channels, a calculation model of critical pressure of downhole fracture pressure and sand production is established. The conclusions show that the best perforation azimuth of oriented perforation is along the direction of the maximum horizontal principal stress.