高温高产气井冲蚀对油管柱结构完整性的影响

Influence of high temperature and high yield gas well erosion on structural integrity of oil string

针对高温超深井在高产携砂生产工况下易造成管柱完整性失效的问题,基于现有管柱结构完整性标准的不足进行了管柱冲蚀工况与载荷风险双重作用的管柱完整性研究,建立油管抗冲蚀能力判别式,利用冲蚀预测模型和剩余强度理论建立冲蚀后剩余强度计算方法,得到组合油管安全系数和极限服役寿命,优选高温高产气井油管组合方式。研究结果表明:当产量一定时,油管下部适当选用内径大、壁厚较薄的组合油管可降低临界冲蚀流量,提高油管抗冲蚀能力;相比改变组合油管上部壁厚,改变下部油管壁厚能明显提高抗冲蚀能力,即增加下部油管壁厚至12.70 mm,冲蚀速率可以达到最大值1.105 mm/a;不同壁厚“5+5”组合油管的计算结果建议优选“5(壁厚为12.70 mm)+5(壁厚为11.10、9.19 mm)”的组合结构油管,以保障油田安全高效生产。

Aiming at the problem of string integrity failure in high-temperature and ultra-deep wells under high-yield and sand-carrying production conditions,based on the lack of existing string structural integrity standards,to conduct string integrity was conducted with the dual effects of string erosion and load risk.A discriminant formula was established for tubing anti-erosion capability and erosion prediction model and residual strength theory were used to establish a calculation method for residual strength after erosion,to obtain the combined tubing safety factor and ultimate service life,and to optimize the combination of high temperature and high production gas well tubing.The research results show that when the output is constant,the lower part of the tubing should be appropriately selected as a combination tubing with a large inner diameter and a thinner wall,which can reduce the critical erosion flow and improve the erosion resistance of the tubing string;compared to changing the upper wall thickness of the combined tubing,the lower tubing wall is changed.Thickness can significantly improve the erosion resistance,increase the wall thickness of the lower tubing to 12.70 mm,and the erosion rate can reach the maximum value of 1.105 mm/a;the calculation of“5+5”combined tubing with different wall thicknesses shows that it is recommended to optimize“5(combined structure tubing with a wall thickness of 12.70 mm)+5(wall thickness of 11.10 mm and 9.19 mm)”to ensure safe and efficient production in the oilfield.