无阻型高效洗井防污管柱的应用与评价

Application and evaluation of unimpeded anti-fouling efficient flushing string

辽河油田高含蜡区块管柱易结蜡、热洗效率低、洗井污染已成为制约高含蜡、低压力系数、易伤害油藏高效开发的关键因素,为此开展了无阻型防污染洗井管柱技术研究。研制了泵下漏失控制装置,通过浮动阀的设计实现了油层产出液举升过程的无阻流动,而清蜡洗井过程可控制洗井液漏失以防侵入低压油层;同时,通过油管锚定器、油管扶正器和自封封隔器的配合应用,可有效规避油管蠕动及密封时效性差的技术难题。现场测试和先导性试验表明,平均单井洗井作业时间降低53.4%、平均单井洗井液总用量降低53.9%、平均单井产能恢复时间减少112.8 h。此技术可有效提高油井产能、提高洗井效率及有效避免产层伤害,为易结蜡、低压、易伤害油藏开发提供了一种有效方法。

The blocks with high wax content in Liaohe Oilfield are suffered from easy wax precipitation on pipe strings,low thermal flushing efficiency and reservoir contamination due to well flushing,which are the key factors restricting the efficient development of vulnerable oil reservoirs with high wax content and low pressure coefficient.To deal with these difficulties,open-flow anti-fouling flushing string technology was studied.The pump leakage control device was developed.Based on the design of floating position valve in this device,open flow of the liquid produced from oil layers is realized in the process of lifting and lost circulation can be controlled and prevented from invading into low-pressure oil layers in the process of wax removal and well flushing.In addition,the technical difficulties of tubing creep and poor sealing time efficiency can be avoided effectively based on the collaborative application of tubing anchor,tubing centralizer and self-sealing packer.Field test and pilot test show that the average flushing time per well is decreased by53.4%,the average flushing fluid consumption per well is reduced by53.9%and the average productivity recovery time per well is cut down by112.8h.In conclusion,this technology can effectively increase oil well productivity and well flushing efficiency and avoid pay zone contamination,and it provides one effective way for the development of vulnerable oil reservoirs with high wax content and low pressure coefficient.