利用水平井提高稠油油藏剩余油采收率技术

为了挖潜辽河油田A块超稠油油藏井间剩余油,应用数值模拟软件描述了水平井有利部署区温度场、压力场及剩余油分布:蒸汽吞吐周期较高的生产井周围油层动用情况较好,油层温度高达190～210℃,但蒸汽加热的有效面积只在井筒周围20～30 m,井间仍然有大部分区域处于45～65℃的低温状态;由于蒸汽吞吐过程中的汽窜现象,部分井之间有热连通形成.动用最好的区域油层压力为3.00 MPa,一般在3.40～3.90 MPa.井间存在大量剩余油,剩余油饱和度大于50%.在兴Ⅲ、兴Ⅱ_2油层单层厚度大干5 m区域整体部署水平井30口,水平段长度250～400 m.模拟预测水平井蒸汽吞吐8周期后,平均单井累计产油25 220 t,油汽比0.42,采出程度为31.5%.与直井生产效果对比,加密水平井可以挖潜稠油油藏井问剩余油,提高该区块采收率.图5表3参10

Technique of enhancing recovery of remaining oil in heavy oil reservoirs by horizontal wells

To excavate the remaining oil between the wells of super-heavy oil reservoirs in A Block of Liaohe Oilfield, the temperature field, pressure field and distribution of remaining oil are described by numerical simulation software where the horizontal wells were deployed. The employing degree is good around the production wells which have more steam stimulation cycles, the reservoir temperature attains .190-210℃, but the effective heating area around wellbore is 20-30 m, the majority region is still 45-65℃ between the wells. Because of steam channeling, the thermal channel is buildup between some wells. The reservoir pressure is 3.00 MPa where the employing degree is good, generally, 3. 40-3. 90 MPa. A large amount of remaining oil exists between the wells and the saturation of remaining oil is above 50%. Thirty horizontal wells are deployed in Ⅻ and Ⅻ_2 formations where the effective thickness of individual bed is more than 5 m. The length of horizontal section is 250 to 400m. According to the simulation, when the horizontal wells produce by eight steam stimulation cycles, the average cumulative oil production of a single horizontal well is 25 220 t, the oil-steam ratio is 0. 42 and the degree of recovery is 31.5%. Compared with vertical wells, the infill horizontal wells can enhance oil recovery.