宁武盆地煤层气储层敏感性研究及钻井液技术  

Study on Coalbed Methane Reservoir Sensitivity in Ningwu Basin and Drill-in Fluid Technology

作　　者：凡帆[1] 郑玉辉[1] 吕海燕[2] 

机构地区：[1]川庆钻探工程公司钻采工程技术研究院低渗透油气田勘探开发国家工程实验室,西安710021 [2]中国石油长庆油田分公司油气工艺研究院,西安710021

出　　处：《钻井液与完井液》2016年第1期48-51,共4页Drilling Fluid & Completion Fluid

基　　金：中国石油川庆钻探工程有限公司科技项目"山西;陕西煤层气安全钻井及储层保护钻井液技术研究"(CQ2012B-8-2-3)

摘　　要：对宁武盆地煤层气储层进行了应力敏感、碱敏和水敏评价实验。研究结果表明,宁武盆地煤层气储层为强应力敏感性、中等碱敏性和中等偏强水敏性。提出通过控制钻井液密度和pH值、提高钻井液的封堵性和抑制性,降低钻井液对储层伤害的技术思路,并研究出一套适合煤层气井的封堵成膜CQ-FDC钻井液：（0.2%~0.3%）有机硅G304＋（2%~5%）复合盐FHY-2＋（0.3%~0.5%）提黏剂G310＋（1%~3%）降滤失剂G301＋（1%~2%）封堵剂G325＋NaOH。室内评价结果表明,该钻井液12 h线性膨胀降低率为71.56%,具有良好的抑制性;储层保护效果好,对储层4~#煤和9~#煤的伤害率小于15%。该钻井液技术在宁武盆地煤层气井现场试验了6口井,均取得成功,其平均井径扩大率为15.77%,对储层岩心的平均伤害率为16.73%,利于保护储层,且平均机械钻速较高。Stress sensitivity, alkali sensitivity and water sensitivity conducted on rock samples taken from coalbed methane reservoir of the Ningwu Basin demonstrate that strong stress sensitivity, moderate alkali sensitivity and moderate-strong water sensitivity exist in the reservoir formations. It is suggested that the drilling fluid used in reservoir drilling in the Basin should have controlled mud weight and pH value, high temporary plugging capacity and inhibitive capacity, which help minimize damage to the permeability of reservoir rocks. A set of filming drill-in fluid, CQ-FDC, suitable for drilling the coalbed methane is as follows： （0.2% -0.3%）G304 （organosilicon） ＋ （2%-5%）FHY-2 （compound salts） ＋ （0.3%-0.5%） G310 （viscosifier） ＋ （1%-3%）G301 （filter loss reducer） ＋ （1% -2%） G325 （temporary plugging agent） ＋ NaOH. This drill-in fluid showed in laboratory experiment percent reduction in linear swelling of cores by 71.56% after 12 h of test. Permeability recovery experiment showed that damage of the drill-in fluid to the permeability of coal samples 4^# and 9^# was less than 15%. CQ-FDC has been successfully applied in 6 coalbed methane wells in Ningwu Basin, average hole enlargement of these wells being 15.77%, and average rate of permeability impairment of the reservoir rocks was 16.73%. Average ROP of the six wells was increased in comparison with offset wells.

关 键 词：煤层气井 储层敏感性 钻井完井液 抑制性 宁武盆地 

分 类 号：TE254.3[石油与天然气工程—油气井工程]