【摘要】：衰竭式開采凝析氣藏過程中,隨地層壓力降至露點壓力后,地層內(nèi)會出現(xiàn)反凝析現(xiàn)象。凝析氣藏反凝析污染嚴重影響氣井產(chǎn)能,對于低滲致密凝析氣藏,凝析油污染的影響尤為嚴重。因此合理評價凝析油污染程度,并探索出相應(yīng)的解除污染方法可以提高凝析氣藏采收率。將配制的2種符合要求的地層流體通過PVT實驗測試其高溫高壓物性參數(shù),從現(xiàn)場獲取了2組長巖心,進行氣源與巖心聯(lián)合衰竭模擬近井區(qū)凝析油污染,巖心單獨衰竭模擬遠井區(qū)凝析油污染,共進行了8組長巖心實驗,通過氣相有效滲透率值定量比較了每一組實驗對應(yīng)的反凝析污染程度。針對凝析油污染較嚴重的實驗組開展解除污染實驗,對比不同解堵方式的效果。 研究成果表明采用相同流體和相同巖心,模擬近井污染時凝析氣氣相滲透率下降幅度更大；相同驅(qū)替方式和相同巖心中,凝析油含量較高的凝析氣產(chǎn)生的凝析油污染更嚴重；相同驅(qū)替方式和相同流體條件下,巖心滲透率越大,凝析油污染程度較小。從現(xiàn)場實際及工藝要求來看,BK氣藏先期通常采用衰竭式開采,因此解除污染實驗是在最大反凝析液對應(yīng)壓力(依據(jù)PVT定容衰竭實驗測試結(jié)果)下進行的：注入0.1烴類孔隙體積(Hydrocarbon Pore Volume,縮寫為HCPV)干氣,注0.05HCPV甲醇+0.05HCPV干氣,注0.1HCPV氮氣,提高溫度15℃,提高溫度30℃。實驗結(jié)果顯示五種方案均在一定程度上緩解了反凝析污染,而對于BK凝析氣藏,推薦采用注干氣這種方案解除反凝析污染。本文的研究成果深化了對凝析油污染機理與解除方法的認識,對開采同類氣藏起到一定指導(dǎo)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，

本文編號：2209296