摘要
松辽盆地古龙凹陷页岩油是大庆油田重要的接替领域。由于古龙页岩油储层地质条件独特,水平页理纹层发育,压裂时在近井端易形成复杂裂缝形态,裂缝转角大,易脱砂,导致主压裂施工中加砂困难,压力波动幅度大,无法有效连续加砂。为降低连续加砂施工难度,基于流体力学理论和颗粒冲蚀理论建立模型,利用有限元迭代法模拟低砂比段塞阶段支撑剂对裂缝转角的冲蚀效应。模拟结果表明,裂缝转角处的冲蚀效应与排量和砂比呈正相关,与压裂液黏度呈负相关。基于模拟结果建立排量、砂比及压裂液黏度与冲蚀效应的关系图版,并依据图版对试验井低砂比段塞阶段压裂液物性排量等施工参数进行优化,施工排量16m3/min,在砂比5%、压裂液黏度20mPa·s条件下缝内冲蚀效果最好。充分利用段塞加砂阶段,打磨裂缝转角,控制近井端裂缝形态,降低连续加砂施工难度。
Shale oil in Gulong Sag of Songliao Basin is an important replacement field for the Daqing Oilfield.Due to the unique geological conditions of the Gulong shale oil reservoirs and the development of horizontal bedding,complex fracture morphology is easy to form near the wellbore end during fracturing,the fracture cor ner is large and the sand is easy to remove.As a result,it is difficult to add sand in the main fracturing op-eration and the pressure fluctuation is large,which makes it impossible to effectively add sand continuously.To reduce the difficulty of continuous sand adding,a model was established based on fluid mechanics theory and particle erosion theory,and a finite element iterative method was used to simulate the erosion effect of prop-pant on fracture corners in the slug stage with low sand concentration.The simulation results show that the ero-sion effect at the fracture corner is positively correlated with the displacement and sand ratio,and negatively correlated with the fracturing fluid viscosity.Based on the simulation results,a diagram of the relationship be-tween displacement,sand concentration,fracturing fluid viscosity,and erosion effect was established,and accord-ing to the diagram,construction parameters such as fracturing fluid physical property and displacement in the slug stage with low sand concentration of the test wells were optimized.When the displacement is 16m^(3)/min,the erosion effect in the fracture is the best under the sand concentration of 5%and fracturing fluid viscosi-ty of 20mPa·s.The stage of slug sand adding should be made full use to reduce the difficulty of continuous sand adding by polishing the fracture corners and controlling the fracture shape near the wellbore end.
作者
陶飞宇
Tao Feiyu(Daqing Oilfield Limited Company,Daqing Heilongjiang 163453)
出处
《中外能源》
CAS
2024年第2期53-57,共5页
Sino-Global Energy
关键词
低砂比
段塞
裂缝转角
冲蚀效应
连续加砂
压裂施工参数
low sand concentration
slug
fracture corner
erosion effect
continuous sand adding
fracturing operation parameter
