特稠油油藏多元热流体吞吐技术研究与应用

Research and Application of Multi-Component Thermal Fluid Stimulation in the Extra-Heavy Oil Reservoir

目前辽河油田洼38块沙三段油层已进入蒸汽吞吐末期,周期油汽比接近经济开采极限,油井普遍低产低效。针对该问题,结合现场设备适应性,应用数值模拟及油藏工程方法对多元热流体吞吐注采参数进行研究。研究表明,洼38块沙三段油层多元热流体吞吐合理注采参数为:天然气注气强度为1 800~2 100 m^3/m,空气注气强度为18 000~21 000 m^3/m,注水强度为26. 3~35. 7 t/m;天然气注气速度为1 400~1 600 m^3/d,空气注气速度为14 000~16 000 m^3/d,注水速度为20~25 t/d;焖井时间为6~8 d,蒸汽过热度为8~9℃;先注入蒸汽再注入多元热流体效果较好。洼38块沙三段油层多元热体试验井取得较好的试验效果,平均单井日产油量为前一周期蒸汽吞吐的2倍,含水率由蒸汽吞吐阶段的95%下降至80%左右。该研究为稠油油藏蒸汽吞吐后期改善开发效果提供了技术参考。

The cycle oil-steam ratio is close to economic production limit and the wells are characterized by low and inefficient production in the late steam stimulation stage of the Sha-3 reservoir in the Wa38 block of Liaohe Oilfield. Considering the field equipment capacity,numerical simulation and reservoir engineering methods were adopted to study the injection-production parameters for multi-component thermal fluid stimulation treatment. Result indicates that the reasonable injection-production parameters were provided for the Sha-3 reservoir of Wa38 block. The natural gas injection intensity is 1 800~2 100 m^3/m,the air injection intensity is 18 000~21 000 m^3/m,and the water injection intensity is 26. 3~35. 7 t/m. The natural gas injection rate is 1 400~1 600 m^3/d,the air injection rate is 14 000~16 000 m^3/d,and the water injection rate is 20~25 t/d. The soaking period is 6 ~8 d and the steam superheat degree is 8~9 ℃ . A better performance can be realized by steam injection before multi-component thermal fluid injection. A successful pilot test has been carried out in the testing well of Sha-3 reservoir in the Wa38 block,the average daily oil production was doubled than that of steam stimulation in the previous cycle,and the water-cut was reduced from 95% in the steam-stimulation stage to 80% at present. This research could provide certain technical references for improving development performance in the late stage of steam stimulation in heavy-oil reservoir.