BK致密气藏凝析油污染评价及解除方法研究
发布时间：2018-08-28 11:45
【摘要】：衰竭式开采凝析气藏过程中,随地层压力降至露点压力后,地层内会出现反凝析现象。凝析气藏反凝析污染严重影响气井产能,对于低渗致密凝析气藏,凝析油污染的影响尤为严重。因此合理评价凝析油污染程度,并探索出相应的解除污染方法可以提高凝析气藏采收率。将配制的2种符合要求的地层流体通过PVT实验测试其高温高压物性参数,从现场获取了2组长岩心,进行气源与岩心联合衰竭模拟近井区凝析油污染,岩心单独衰竭模拟远井区凝析油污染,共进行了8组长岩心实验,通过气相有效渗透率值定量比较了每一组实验对应的反凝析污染程度。针对凝析油污染较严重的实验组开展解除污染实验,对比不同解堵方式的效果。 研究成果表明采用相同流体和相同岩心,模拟近井污染时凝析气气相渗透率下降幅度更大；相同驱替方式和相同岩心中,凝析油含量较高的凝析气产生的凝析油污染更严重；相同驱替方式和相同流体条件下,岩心渗透率越大,凝析油污染程度较小。从现场实际及工艺要求来看,BK气藏先期通常采用衰竭式开采,因此解除污染实验是在最大反凝析液对应压力(依据PVT定容衰竭实验测试结果)下进行的：注入0.1烃类孔隙体积(Hydrocarbon Pore Volume,缩写为HCPV)干气,注0.05HCPV甲醇+0.05HCPV干气,注0.1HCPV氮气,提高温度15℃,提高温度30℃。实验结果显示五种方案均在一定程度上缓解了反凝析污染,而对于BK凝析气藏,推荐采用注干气这种方案解除反凝析污染。本文的研究成果深化了对凝析油污染机理与解除方法的认识,对开采同类气藏起到一定指导作用。
[Abstract]:In the process of depleted condensate gas reservoir, reverse condensate will occur in the formation after the pressure drops to dew point. Reverse condensate pollution in condensate gas reservoir seriously affects gas well productivity, especially for condensate gas reservoir with low permeability. Therefore, reasonable evaluation of the degree of condensate pollution and exploration of the corresponding decontamination method can improve the recovery of condensate gas reservoir. The two kinds of formation fluids which meet the requirements are tested by PVT experiment, and 2 groups of cores are obtained from the field to simulate condensate oil pollution in the near well area by combined gas source and core failure. The condensate oil pollution in the far well area was simulated by single core failure. Eight core experiments were carried out, and the reverse condensate pollution degree corresponding to each group of experiments was compared quantitatively by the effective permeability value of gas phase. The decontamination experiment was carried out in the experimental group with serious condensate oil pollution, and the effects of different ways of removing plugging were compared. The results show that the gas phase permeability of condensate gas decreases more when the pollution is near well by using the same fluid and the same core, and the condensate pollution caused by the condensate gas with higher condensate oil content is more serious with the same displacement mode and the same core. Under the same displacement mode and the same fluid condition, the higher the core permeability, the less the pollution of condensate oil. According to the field practice and technological requirements, the BK gas reservoir is usually prematurely exploited by exhaustion type. Therefore, the decontamination experiment was carried out under the corresponding pressure of the maximum reverse condensate (based on the test results of PVT constant volume exhaustion test): injecting 0.1 hydrocarbon pore volume (Hydrocarbon Pore Volume, abbreviated as HCPV) dry gas, injecting 0.05HCPV methanol 0.05HCPV dry gas, injecting 0.1HCPV nitrogen gas, The temperature is raised by 15 鈩，
本文编号：2209296
[Abstract]:In the process of depleted condensate gas reservoir, reverse condensate will occur in the formation after the pressure drops to dew point. Reverse condensate pollution in condensate gas reservoir seriously affects gas well productivity, especially for condensate gas reservoir with low permeability. Therefore, reasonable evaluation of the degree of condensate pollution and exploration of the corresponding decontamination method can improve the recovery of condensate gas reservoir. The two kinds of formation fluids which meet the requirements are tested by PVT experiment, and 2 groups of cores are obtained from the field to simulate condensate oil pollution in the near well area by combined gas source and core failure. The condensate oil pollution in the far well area was simulated by single core failure. Eight core experiments were carried out, and the reverse condensate pollution degree corresponding to each group of experiments was compared quantitatively by the effective permeability value of gas phase. The decontamination experiment was carried out in the experimental group with serious condensate oil pollution, and the effects of different ways of removing plugging were compared. The results show that the gas phase permeability of condensate gas decreases more when the pollution is near well by using the same fluid and the same core, and the condensate pollution caused by the condensate gas with higher condensate oil content is more serious with the same displacement mode and the same core. Under the same displacement mode and the same fluid condition, the higher the core permeability, the less the pollution of condensate oil. According to the field practice and technological requirements, the BK gas reservoir is usually prematurely exploited by exhaustion type. Therefore, the decontamination experiment was carried out under the corresponding pressure of the maximum reverse condensate (based on the test results of PVT constant volume exhaustion test): injecting 0.1 hydrocarbon pore volume (Hydrocarbon Pore Volume, abbreviated as HCPV) dry gas, injecting 0.05HCPV methanol 0.05HCPV dry gas, injecting 0.1HCPV nitrogen gas, The temperature is raised by 15 鈩，
本文编号：2209296
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