低渗透油田水平井 CO₂复合吞吐技术

Composite CO₂ Huff and Puff Technology on Horizontal Well in Low Permeability Oilfield

于春涛 金雪超

YU Chuntao，JIN Xuechao

为了解决低渗油田水平井因储层非均质性强而发生的注水沿裂缝、高渗条带窜流以及含水高的问题，开展CO2复合吞吐试验技术研究。首先考察了适合酸性条件下的表面活性剂 YQY-1体系的发泡性能和稳泡性能，在获得最佳气液比的基础上开展了水驱-CO2吞吐-CO2泡沫复合吞吐动态评价实验，并进行了现场实验。研究结果表明，YQY-1发泡体系在高温高压下具有较好的起泡性能和稳泡性能，在气液比 1∶1（交替注入）下，CO2复合吞吐对比单一 CO2吞吐注入压力上升 1.9 MPa，采收率提高 11.6%，说明 CO2泡沫复合体系在油藏条件下能够对裂缝、高渗条带起到封堵作用，扩大注气波及体积，启动低渗部位剩余油。现场试验结果表明，CO2复合吞吐增油控水作用明显。图 4表 1参 10

Aimed at the problems of strong channeling and high water cut in the mature development stage for horizontal well in low permeability oilfield due to severe heterogeneity of the reservoirs，the composite CO2 foam huff and puff stimulation technology was studied，a. suitable foam YQY-1 system in CO2 circumstance was screened，the optimal gas-liquid ratio CO2 was determined and the water flooding-CO2 huff and puff-composite CO2 foam huff and puff was simulated in the laboratory. In addition，the composite CO2 foam huff and puff technology was used in field. The results showed that the YQY-1 system had good foamability in the CO2 circumstance. When the CO2 and YQY-1 system was injected alternately at gas-liquid ratio of 1∶1，the injection pressure of the composite CO2 foam huff and puff was increased by 1.9 MPa，and oil recovery was enhanced by 11.6%，compared to that of the CO2 foam huff and puff. In the reservoir conditions，CO2 foam system could temporarily plug high permeability reservoirs and fractures，and the subsequent gas injection could expand swept volume effectively and initiate the remaining oil in low permeability reservoirs. The results of the composite CO2 foam huff and puff technology in the field indicated the oil production was increased and the water cut was decreased obviously.