水平井泡沫流体冲砂洗井技术研究

HORIZONTAL WELL SAND-CLEANOUT WITH FOAM FLUID

针对漏失井使用水基冲砂洗井液不返液或漏失量大的问题,不用添加任何化学堵漏剂,使用低密度泡沫流体冲砂洗井,可有效地减轻低压井中冲砂液的漏失。为此,以流体力学为基础,建立了水平井泡沫流体冲砂洗井的数学模型,给出了边界条件和限制条件,并编制了相应的参数设计程序。通过对水平井泡沫流体冲砂洗井过程的模拟,得到了泡沫流体密度、泡沫质量、压力、泡沫流速在井筒内的分布,以及环空回压与注入压力、井底压力、泡沫流量等参数的关系。现场应用表明,泡沫流体冲砂洗井有效地防止了冲砂液漏失,并且作业后能够迅速恢复生产,延长了平均检泵周期,是清除低压油气井井底出砂的一项有效的技术措施。

Sand-cleanout with foam fluid can effectively reduce leakage of flushing fluid in low pressure oil wells, without the need of any other LCM materials. The mathematical model for horizontal well sand-cleanout is established based on fluid dynamics, boundary and limited conditions are provided, and corresponding parameter design is progrmmed. Through stimulation of foam fluid circulation process in horizontal wells, this paper expounds distributions of foam density, foam quality, pressure and foam velocity in wellbore, and all kinds of relationships between annular back-pressure and some other parameters like injection pressure, bottom-hole pressure, and foam fluid flow rate, etc. The results of application show that sand-cleanout with foam fluid can effectively prevent fluid from leakage, oil production can be recovered soon after the sand-cleanout operation, and pump check interval can be prolonged. Sand-cleanout with foam fluid is a kind of effective method to remove bottom-hole sand of low pressure oil wells.