威远地区龙马溪组页岩气水平井油基钻井液研究

发布时间：2018-03-10 15:31

本文选题：龙马溪组　切入点：页岩气　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：天然气作为一种清洁能源在国家能源安全中的战略地位越来越重要,我国天然气的对外依存度也呈逐年上升的趋势。页岩气作为我国天然气资源的重要接替,其勘探开发正越来越受到关注和重视。目前国际上开发页岩气一般采用油基钻井液水平井钻井技术,技术相对成熟,并已取得较好的效果。但我国页岩气开发时间短,油基钻井液技术尚不成熟,与国外相比还存在较大的差距。为此必须开展系统研究,开发适合于我国页岩气水平井钻井的油基钻井液体系,以适应页岩气自主规模化开发的需要。从已有的现场钻井实践可知,现有油基钻井液面临着对页岩地层的封堵性较差、井壁稳定能力不足等问题。为此,本文在对威远地区龙马溪组页岩地层岩石组构特征及已钻井工程资料系统分析的基础上,针对性地开展了油基钻井液体系研究,取得了以下认识和成果： 1)该地区页岩黏土矿物总量在29.53%～37.43%之间,石英含量分布在33.9%～43.67%,脆性矿物总量分布在54.69%～62.53%,含少量白云石；黏土矿物以伊利石为主,含伊/蒙混层,无蒙脱石,为弱膨胀性；层理、宏观裂缝、微裂缝、微孔隙都较发育,其中微裂缝开度在5μm以上。因此,必须强化油基钻井液的封堵性。 2)该地区页岩原岩强度较高,脆性强,钻井过程中易出现井壁掉块现象,需要油基钻井液具有良好的页岩井壁稳定能力。 3)在对处理剂进行优选的基础上,获得了油基钻井液体系配方：5#白油+25%CaCl2(油水比为85:15)+3%乳化剂ETS-1+2%CaO+2%降滤失剂CF+1%润湿剂WEP+1%封堵剂CB+0.66%刚性封堵材料CaCO3(800目)+0.5%提切剂RZL+重晶石。该体系中压滤失量为0、高温高压滤失量小于2mL、破乳电压大于1200V,具有较好的高温高压流变性、稳定性、抑制性和抗污染性。封堵性能评价结果表明,该体系具有良好的封堵性,在0.69MPa下,30min砂床侵入深度为4cm,PPA高温高压滤失量为0。钻井液对页岩强度保持能力实验表明,其对页岩岩样强度具有很好的保持性。 4)该油基钻井液体系在威A井水平井段应用中表现出了良好的稳定性、抑制性、润滑性、携砂能力及对页岩井壁的稳定性,在整个井段钻进顺利,无明显垮塌现象发生。钻井液体系在钻进过程中的流变性能稳定,能够满足该页岩气水平井段作业要求,但仍有继续优化的空间。
[Abstract]:As a kind of clean energy, natural gas plays a more and more important role in national energy security, and the external dependence of natural gas in China is also increasing year by year. Shale gas is an important replacement of natural gas resources in China. The exploration and development of shale gas has been paid more and more attention. At present, oil based drilling fluid horizontal well drilling technology is generally used in the development of shale gas in the world. The technology is relatively mature and has achieved good results. However, the development time of shale gas in China is short. Oil based drilling fluid technology is still immature, and there is still a big gap compared with foreign countries. Therefore, it is necessary to carry out systematic research to develop oil based drilling fluid system suitable for shale gas horizontal well drilling in China. In order to meet the needs of shale gas independent large-scale development, the existing oil-based drilling fluid is faced with some problems such as poor plugging ability to shale formation and insufficient wellbore stability ability, according to the existing field drilling practice. Based on the systematic analysis of rock fabric characteristics and drilling engineering data of the shale formation of Longmaxi formation in Weiyuan area, the oil based drilling fluid system has been studied in this paper, and the following results have been obtained:. 1) the total mineral content of shale clay in this area is between 29.53% and 37.43%, the content of quartz is 33.9%, the total amount of brittle minerals is 54.6910% and 62.53%, and the clay is mainly Illite, with the mixed layer of Illite / montmorillonite, without montmorillonite, which is weakly expansive. The macro fracture, micro fracture and micropore are all developed, in which the opening of micro fracture is above 5 渭 m. Therefore, the plugging ability of oil base drilling fluid must be strengthened. 2) the shale source rock in this area is of high strength and brittleness, and it is easy to appear the phenomenon of wellbore block loss during drilling, which requires the oil-base drilling fluid to have good shale sidewall stability. 3) on the basis of the optimal selection of the treatment agent, The oil base drilling fluid system formulation: White oil 25Cl 2 (oil-water ratio 85: 15) 3% emulsifier ETS-1 2O 2% filter reducer CF 1% wetting agent WEP 1% plugging agent CB 0.66% rigid plugging material CaCO3(800 mesh) 0.5% extractant RZL barite was obtained. The medium pressure filtration loss is 0, the high temperature and high pressure filtration loss is less than 2 mL, the demulsification voltage is more than 1 200 V, and has good high temperature and high pressure rheology. Stability, inhibition and pollution resistance. The evaluation of plugging performance shows that the system has good plugging performance, and the invasion depth of sand bed is 4 cm / m PPA at 0.69 MPA for 30 min, and the filtration loss of PPA at high temperature and high pressure is 0. The experimental results show that the drilling fluid has the ability to retain shale strength. It can maintain the strength of shale rock samples. 4) the oil-base drilling fluid system has shown good stability, inhibition, lubricity, sand carrying ability and stability to the shale well wall in the horizontal section of WeiA well. There is no obvious collapse. The rheological property of drilling fluid system is stable, which can meet the operational requirements of the shale gas horizontal section, but there is still room for further optimization.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE254

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