碳酸盐岩缝洞型油藏提高采收率关键技术

Key technologies for EOR in fractured-vuggy carbonate reservoirs

中国碳酸盐岩缝洞型油资源量丰富,探明石油地质储量达29.3×108 t,已经成为中国油气勘探开发和油气增储上产的重要领域。由于深埋5500 m碳酸盐岩缝洞体的描述精度低、流动模式多样、模拟预测难度大,注水窜流易造成油井暴性水淹,导致采收率低仅为15.9%,此类油藏开发是世界级难题。经过多年的研究与实践,形成地球物理描述、地质建模、注水注气和酸压改造等提高采收率系列技术,单元应用后储量动用率提高了42%,同时已提高采收率2.3%,对同类深层、超深层强非均质性油藏开发具有借鉴作用。

China is rich in fractured-vuggy carbonate oil reserves,with proved reserves in place of 29.3×108 t,which has become an important target for China's hydrocarbon exploration and development,and important contributor for the increase of reserves and production.Due to the low reservoir and fluid description accuracy,the variation in flow patterns,and the difficulty to predict flow pattern by simulation of carbonate fractured-vuggy reservoirs in a burial depth of 6500m,the transverse flow in water injection is prone to cause abrupt watered-out wells,resulting in a low recovery rate of only 14.9%.Development and production in such reservoirs are a world-class problem.After many years of research and practice,we developed a series of technologies to enhance oil recovery,including geophysical description,geological modeling,water and gas injection,and acid fracturing.The developed STOOIP has increased 42%with an EOR(enhanced oil recovery)of 2.3 percent in the structural units tested with the new technologies,which are applicable to the development of similar deep or ultra-deep reservoirs with strong heterogeneity.