Analysis on the Feasibility of Reducing Drilling Fluid Density with Silicate Drilling Fluid in Drilling Unstable Formations
-
摘要: 珠江口盆地古近系地层在钻井过程中,多口井出现坍塌、卡钻、起下钻遇阻等井壁失稳问题,现场通过增加钻井密度解决垮塌问题,但又出现压差卡钻、钻井时效低的问题。从黏土矿物含量分析、扫描电镜、滚动回收率及膨胀性实验入手,分析珠江口盆地古近系地层井壁失稳原因。古近系地层为微裂缝发育,在钻井过程中井壁周围应力发生变化及钻井液侵入,引起井壁坍塌,继而出现卡钻、起下钻遇阻等问题。为了解决以上问题,结合硅酸盐钻井液抑制性强、封堵性好、可增强岩石强度的特点,降低地层坍塌压力。对硅酸盐水基防塌钻井液进行优化及性能评价,结果表明,其性能参数满足钻井要求,具有提高岩石内聚力、抗压能力的特点,同时与古近系已用PLUS-KCl钻井液、油基钻井液相比,优化的硅酸盐水基防塌钻井液浸泡后岩石具有抗压强度高、内聚力高等特点,其内聚力高达11.7 MPa,是PLUS-KCl钻井液的1.9倍,是油基钻井液的1.5倍,可见在保证井壁稳定的前提下,用硅酸盐钻井液降低地层坍塌压力是可行的。Abstract: Drilling operations in the Pearl River Mouth Basin have been face with downhole troubles in the Paleogene System, such as borehole wall collapsing, pipe sticking and difficulties in tripping the drill string. Addressing these problems with increased drilling fluid density resulted in other problems such asdifferential pipe sticking and low time efficiency. The causes of borehole wall collapse in drilling the Paleogene System in the Pearl River Mouth Basin were analyzed through clay content analysis, SEM experiment, hot rolling test and core swelling test. The Paleogene System is developed with micro fractures, formation stress change due to drilling operation and invasion of mud filtrate into the micro fractures cause borehole wall collapse, followed by pipe sticking and difficulties in tripping the drill string. To address these problems, silicate drilling fluid was adopted to drill the Paleogene formation. Silicate drilling fluid has good inhibitive capacity and plugging capacity. It helps enhance the strengths of the rocks and reduce the collapse pressure of the formation drilled, thereby reducing the density of the drilling fluid to balance the formation pressure. Performance evaluation of an optimized silicate drilling fluid showed that its properties satisfy the requirements of drilling operations. It helps increase the cohesion and compressive capacity of rocks. Compared with the PLUS-KCl drilling fluid and oil base drilling fluid that have been already used in drilling the Paleogene formation, the optimized silicate drilling fluid performed much better; rocks immersed in the optimized silicate drilling fluid had higher compressive strength and cohesion, the cohesion was tested to be 11.7 MPa, 1.9 times of the cohesion of the rock samples immersed in PLUS-KCl drilling fluid, or 1.5 times of the cohesion of the rock samples immersed in oil base drilling fluid. These experimental results proved that silicate drilling fluid can be used to reduce the density of the drilling fluid while maintaining the borehole wall in stable condition.
-
Key words:
- Borehole destabilization /
- Pipe sticking /
- Silicate drilling fluid /
- Density reduction /
- Rock strength
-
[1] 鄢捷年. 钻井液工艺学[M]. 北京:中国石油大学出版社,2013:6-7 YAN Jienian.Drilling fluid technology[M]. Beijing:China university of petroleum press,2013:6-7 [2] 梁大川,罗平亚,刘向君,等. 钻井液处理剂及体系对泥页岩坍塌压力的影响研究[J]. 钻采工艺,2011:34(2):83-84.LIANG Dachuan,LUO Pingya,LIU Xiangjun, et al. Study on the effect of drilling fluid additives and system on shale collapse pressure[J].Drilling & Production Technology,2011,34(2):83-84. [3] 王书琪,梁大川,何涛,等. 降低地层坍塌压力增加幅度的钻井液技术[J]. 钻井液与完井液,2008,25(3):22-24.WANG Shuqi, LIANG Dachuan, HE Tao,et al.Drilling fluid technology for reducing the increasing amplitude of formation collapse pressure[J].Drilling Fluid & Completion Fluid,2008,25(3):22-24. [4] 孟丽艳,黄宁,张麒麟. 硅酸盐钻井液体系的研究进展[J]. 精细石油化工进展,2012,13(12):37-38.MENG Liyan,HUANG Ning,ZHANG Qilin.Progress of research on silicate drilling fluid system[J].Advances in Fine Petrochemicals,2012,13(12):37-38 [5] DUNCAN J,MCDONALD M. Exceeding drilling performance and environmental requirements with potassium silicate based drilling fluid[C]. SPE 86700-MS, 2004. [6] 罗健生,徐绍成,王雪山,等. 硅酸盐钻井液对泥页岩地层井眼稳定性影响研究[J]. 钻井液与完井液, 2006,23(2):18-20LUO Jiansheng,XU Shaocheng,WANG Xueshan,et al. Influence of silicate base drilling fluid on wellbore stability of shale[J]. Drilling Fluid & Completion Fluid, 2006,23(2):18-20 [7] 孙玉学,杨婧娜,朱红. 硅酸盐钻井液室内评价与研究[J]. 科学技术与工程,2010,10(25):6068-6270.SUN Yuxue,YANG Jingna,ZHU Hong. Interior evaluation and reasarch of silicate drillfluid[J].Science Technology and Engineering,2010,10(25):6068-6270. [8] 汪传伟,李皋,严俊涛,等. 川南硬脆性页岩井壁失稳机理实验研究[J]. 科学技术与工程,2012,12(30):8012-8014.WANG Chuanwei,LI Gao,YAN Juntao,et al. Experiment study of hard and brittle shale wellbore instability mechanism in south of Sichuan[J]. Science technology and Engineering,2012,12(30):8012-8014. [9] 罗泉源,王家豪,柳保军,等. 白云凹陷东部古近系层序格架及结构模式[J]. 科学技术与工程,2017,17(22):34-40.LUO Quanyuan,WANG Jiahao,LIU Baojun,et al. Sequence stratigraphic framework and sequence textures pattern of the Paleogene in the eastern baiyun sag,the south China sea[J]. Science Technology and Engineering, 2017,17(22):34-40. [10] 艾贵成. 硅酸盐钻井液流变性与滤失造壁行探讨[J]. 断块油气田,2008,15(4):109-111.AI Guicheng. Discussion on rhelolgical and filtrating properties of silicate drilling fluid[J]. Fault-Block Oil & Gas Field,2008,15(4):109-111. [11] 丁彤伟,鄢捷年. 硅酸盐钻井液的抑制性及其性能影响因素的研究[J]. 石油钻探技术,2005,33(6):32-35.DING Tongwei,YAN Jienian. Studies on the inhibitive character and its influence factors of silicate drilling fluid[J]. Petroleum Drilling Techniques,2005,33(6):32-35. [12] 刘志良,戎克生,张贵仪. 硅酸钾钻井液室内研究[J]. 新疆石油天然气,2013,9(4):20-23.LIU Zhiliang,RONG Kesheng,ZHANG Guiyi. Laboratory study on potassium silicate drilling fluid system[J].Xinjiang Oil & Gas,2013,9(4):20-23.
点击查看大图
计量
- 文章访问数: 579
- HTML全文浏览量: 186
- PDF下载量: 227
- 被引次数: 0