稠油环空掺稀气举技术——以吐哈油田吐玉克区块为例

为了提高稠油冷采开发水平,利用高18.25 m的垂直多相管流实验回路开展了稠油气举流动实验及压降模型优选。基于实验结果及井筒传热机理,建立了环空掺稀气举井筒压力-温度梯度耦合预测模型,并可通过耦合环空与油管内流动进行循环迭代求解。实验结果表明:注气有助于稠油与稀油更快更充分混合;压降模型优选表明,Ansari模型误差相对最小,为12.12% 。针对吐哈油田吐玉克区块稠油井筒举升困难的实际情况,提出了稠油环空掺稀+气举工艺思路,并开展了实例井掺稀气举设计,对注气量、掺稀量等进行了敏感性分析。实例设计结果表明,实例井仅靠气举无法生产,其 掺稀生产极限产量可达到16 m³/d,而掺稀+气举极限产量能达到52.5 m³/d;定产油量条件下,在特定范围内增加注气量能极大地减小掺稀量,且井底掺稀气举能极大地提升稠油井的产能。

Heavy oil gas-lift technology assisted with light oil:a case study from Tuyuk block in Tuha oilfield

To improve the cold production of heavy oil, heavy oil gas-lift flowing experiments and optimization of pressure drop model were carried out using 18.25 m vertical multiphase pipe flow test loop. Based on the experiment results and wellbore heat transfer mechanism, wellbore pressure-temperature gradient coupling predictive model was established for gas lift and annulus blending diluting technologies. Moreover, it can be solved by coupling the annulus and tubing flow with the use of loop iteration method. The experiment results show that gas injection can facilitate the sufficient blending of light and heavy oil. The model optimization indicates that Ansari model has the least error of 12.12%. It is difficult to lift the heavy oil wellbore in Tuyuke block of Tuha oilfield, aiming at which gas lift and blending diluting oil technologies was proposed with example design. Then a sensitivity analysis was carried out on the volume of injected gas and added light oil, etc. The example design demonstrates that the well cannot produce only based on gas-lift technology; the maximum productivity is 16 m³/d if applying diluting technology, while in combination with gas-lift technology the maximum output can reach 52.5 m³/d. In case of fixed oil production, the increasing volume of injected gas within the specific range can largely reduce the amount of added light oil, and the productivity of heavy oil well can be significantly improved using gas-lift and blending diluting oil technologies.