稠油油藏多元介质复合蒸汽吞吐驱油机理研究

Displacement Mechanism of Multi-Component Compound Steam Stimulation in Heavy-Oil Reservoir

为研究多元介质复合蒸汽吞吐驱油机理,选取风城油田A区块油样,在温度为150℃、介质段塞尺寸为0. 03倍孔隙体积、回压为4. 00 MPa、驱替速度为0. 5 mL/min条件下,进行单一介质、多元介质组合岩心驱油实验。实验表明,"尿素+起泡剂"组合驱油效果最好。在此基础上,开展三维物理模拟、微观驱油模拟室内实验。结果表明:多元介质高温分解后降黏率可达89%,地层压力提高3. 00 MPa,吸汽剖面改善率达到73%,驱油效率提高近30个百分点。该技术已在A区块19口井进行了现场试验,平均周期产油提高480 t,油汽比提高0. 12,取得较好的开发效果。该研究为改善稠油吞吐后期生产效果提供了新思路。

The crude oil sample of Block A in Fengcheng Oilfield was taken to study the displacement mechanism of multi-component compound steam stimulation. The single-component and multi-component displacement experiments with core combination was performed when the temperature was 150 ℃,the slug size was 0. 03 times of the pore volume,the back pressure was 4. 00 MPa and the displacement rate was 0. 5 mL/min. Research indicates that the displacement experiment with "urea + foaming agent" combination shows the best displacement performance. Laboratory 3D physical simulation and microscopic displacement experiments were carried out based on the completed experiments. Result illustrates that the viscosity reduction rate of the multi-component could reach89% after high-temperature decomposition. The formation pressure was increased by 3. 00 MPa,the improvement ratio of steam injection profile is up to 73%,and the oil displacement efficiency was improved by nearly 30 percentage points. This technology has been tested for 19 wells in Block A. The average cycle oil production has been increased by 480 t,and the oil-steam ratio has been enhanced by 0. 12,which shows better development performance. This research could provide a new understanding to improve the production performance of heavy-oil reservoir with steam stimulation in the late stage.