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杜813块兴隆台油层为超稠油油藏,原油粘度高,50℃时脱气原油粘度50000~246000mPa.s,20℃地面原油密度1.011 g/cm~3。蒸汽吞吐开采的加热半径一般仅为30~40m,个别较好的油层可以到50m左右。而杜813块超稠油吞吐动用半径仅为20~30m,开采难度较大。杜813南块兴隆台油层自2003年开始陆续投入开发,目前已进入吞吐开发后期,油井生产轮次高,排水期延长,吞吐效果变差。1-7周期排水期较短,为0-6天,8周期以上,排水期上升到20-30天,地层中大量冷凝水无法采出,含油饱和度下降,部分原油吸附在岩石孔隙表面,注入高温蒸汽无法有效加热剥离这部分剩余油,致使这部分原油浪费了大量热能,却无法采出。针对上述问题,研究应用CO_2辅助蒸汽吞吐技术,截止目前,累计实施CO_2辅助稠油蒸汽吞吐技术105井次,措施增油14832.2t,效果显著。
Du 813 Xinglongtai oil reservoir is a super-heavy oil reservoir with high crude oil viscosity. The viscosity of degassed crude oil is 50000 ~ 246000 mPa.s at 50 ° C and 1.011 g / cm ~ 3 at 20 ° C. Steam hunt mining heating radius is generally only 30 ~ 40m, some of the better oil layer can be about 50m. The Du 813 ultra-heavy oil throughput only a radius of 20 ~ 30m, mining more difficult. Du 813 South Block Xinglongtai oil and gas reservoirs have been put into development since 2003, and have now entered the late stage of huff and puff development. Oil well production turns high and the drainage period is prolonged, which results in poor throughput. 1-7 cycle drainage period is short, 0-6 days, more than 8 cycles, drainage period rose to 20-30 days, a large number of condensate can not be produced in the formation, oil saturation decreased, part of the crude oil adsorbed on the rock pore surface, Injecting high-temperature steam can not effectively heat and peel this part of the remaining oil, resulting in this part of the crude oil wastes a lot of heat, but can not be produced. In response to the above problems, the application of CO 2 -assisted steam huff and puff technology has been studied. Until now, the cumulative CO 2 -based heavy oil steam huff and puff technology has been implemented for 105 wells and the measures have been taken to increase the oil yield by 14,832.2 t.