摘要
大牛地气田部分水平井存在井底出砂现象限制了气井产能，采用常规冲砂工艺时井筒内流体易漏失到地层，造成地层伤害，为此开展了速度管泡沫冲砂工艺技术研究。综合考虑压力、温度、黏度和流体密度的影响，由力平衡原理建立了水平井泡沫临界携砂流速计算模型，经计算得知水平段临界携砂流速是垂直段1．5倍，倾斜段介于两者之间。基于气井泡沫携砂模型，以鄂尔多斯盆地伊陕斜坡东北部的1口水平井DPS-9井为施工试验井，设计了该井施工参数，即井口回压在5．0MPa内，泡沫液与氮气注入比不超过3：1，冲砂管柱外径优选为38．1mm，冲砂液排量0．062～0．239m^3／min。现场应用结果表明，该技术冲砂作业时间短，避免了流体漏失，对储层伤害小，气井共返砂1．50m^3，日产水4．40m^3，日增气量1．20×10^4^3，增产效果明显。
Sanding in some horizontal well in Daniudi gas field have limited the gas well productivi- ty. Wellbore fluid is prone to leak in to formation during conventional sand washing operation, resulting in formation damage. To address the issue, study on sand washing by CT velocity string has been conducted. Taking the effect of pressure, temperature, viscosity and density of the fluid into consideration, the critical sand-carrying foam flow model for horizontal well has been established based on the force balance principle. Calculation results show that the critical sand-carrying foam flow rate of horizontal section is 1.5 times larger than the vertical section. The critical sand-carrying foam flow rate of inclined section is between the horizontal section and vertical seetion. Based on the sand-carrying foam flow model, field test has been conducted on horizontal test well DPS-9 in the northeast Yishan slope in Ordos Basin. The designed back pressure is within 5.0 MPa. Foam liquid and nitrogen injeetion ratio is no more than 3：1. The optimized sand washing string outer diameter is 38.1 mm. Sand washing fluid displacement is 0. 062 - 0. 239 m^3/min. Field application results shows that the sand washing operation by coiled tubing velocity string has the advantages of short operation time, fluid loss prevention and little damage to formation, with the total sand return of 1.50 m^3 and nissan water 4.40 m^3, and increased gas production of 1.20×10^4 m^3, indicating a sig- nificant EOR performance.
出处
《石油机械》
2015年第9期75-78,82,共5页
China Petroleum Machinery
基金
国家科技重大专项"大型油气田及煤层气开发"(2011ZX05045)
关键词
大牛地气田
水平井
速度管
临界携砂流速
泡沫冲砂
daniudi gas field
horizontal well
coiled tubing velocity string
the critical sand-carrying foam flow
foam sand washing
