王洋, 袁清芸, 赵兵, 方裕燕, 秦飞. 二氧化碳对塔河油田裂缝性储层酸岩反应的影响研究[J]. 石油钻探技术, 2017, 45(1): 78-82. DOI: 10.11911/syztjs.201701014
引用本文: 王洋, 袁清芸, 赵兵, 方裕燕, 秦飞. 二氧化碳对塔河油田裂缝性储层酸岩反应的影响研究[J]. 石油钻探技术, 2017, 45(1): 78-82. DOI: 10.11911/syztjs.201701014
WANG Yang, YUAN Qingyun, ZHAO Bing, FANG Yuyan, QIN Fei. Experiment Research on the Effect of CO2 on Acid-Rock Reactions in Fractured Reservoirs[J]. Petroleum Drilling Techniques, 2017, 45(1): 78-82. DOI: 10.11911/syztjs.201701014
Citation: WANG Yang, YUAN Qingyun, ZHAO Bing, FANG Yuyan, QIN Fei. Experiment Research on the Effect of CO2 on Acid-Rock Reactions in Fractured Reservoirs[J]. Petroleum Drilling Techniques, 2017, 45(1): 78-82. DOI: 10.11911/syztjs.201701014

二氧化碳对塔河油田裂缝性储层酸岩反应的影响研究

Experiment Research on the Effect of CO2 on Acid-Rock Reactions in Fractured Reservoirs

  • 摘要: 为提高塔河油田裂缝性油藏的酸压改造效果,研究了CO2对裂缝性油藏酸岩反应影响的问题。利用自主研制的裂缝性储层酸岩反应仪,基于网状裂缝模型,对考虑CO2影响的不同类型、不同黏度和不同浓度酸液的酸岩反应情况进行了试验评价。试验得出:随着回压增大,酸岩反应产生的CO2转变为超临界态后大量溶于酸液中,酸液流动阻力大幅降低,酸蚀量增大;与胶凝酸及Ⅰ型地面交联酸相比,HCl质量分数为20%的Ⅱ型地面交联酸滤失量小、黏度高,受CO2影响最大,酸岩反应最慢,有利于实现裂缝性储层深穿透酸压的目的。Ⅱ型地面交联酸在YJY井重复酸压中进行了现场试验,与该井应用胶凝酸的首次酸压效果相比,液体效率大幅提高,酸蚀缝缝长大幅增加,压裂后累计产油1.2×104 t,增油效果显著。研究表明,超临界CO2有助于降低酸液流动阻力,提高酸液深穿透能力,提高塔河油田裂缝性储层酸压改造效果。

     

    Abstract: To enhance acid fracturing performance in fractured reservoirs in the Tahe Oilfield,research has been conducted to highlight the impact of CO2 on acid rock reactions in such reservoirs.By using independently developed acid rock reaction instruments and a fracture network model,tests were conducted to study the impact of CO2 on acid rock reactions with different acids,viscosity and concentration.Test results showed that flow resistance of acid may decrease sharply as CO2 generated during acid rock reaction become supercritical,then dissolve in acid massively as back pressure increases.Compared with gelled acid and Type I surface cross-linked acid,Type II surface cross-linked acid with concentration of 20% has less filtering loss,higher viscosity and susceptibility to CO2 and lower acid rock reaction speed.This kind of acid may facilitate acid fracturing to achieve deep penatration in fractured reservoirs.A pilot test was conducted for Type II surface cross-linked acid in the acid refracturing of the Well YJY.Compared with the primary acid fracturing with gelling acid,both fluid efficiency and fracture length increased dramatically.With cumulative oil production of 1.2×104 t after refracturing,productivity enhancement performance has been observed.So research results showed supercritical CO2 could effectively reduce flow resistance of acid,enhance acid penetration and promote the performance of acid-fracturing of fractured reservoirs in the Tahe Oilfield.

     

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