FL-H2-L煤层气五分支水平井绒囊钻井液技术

FL-H2-L五分支水平生产井位于鄂尔多斯盆地吕梁复背斜西翼,目的层为山西组3#、4#、5#煤层3段煤层气藏.该井一开采用膨润土钻井液,二开采用空气、清水钻井液,三开五分支水平井采用无固相绒囊钻井液,其配方为:清水+(0.3％～0.4％)定位剂+(1.0％～1.5％)成层剂+(0.2％～0.3％)强层剂+(0.1％～0.5％)成核剂+(0.1％～0.5％)成膜剂.在现场应用中,控制现场钻井液密度为0.90～0.98 g/cm3,黏度为30～50 s,通过利用绒囊钻井液的自匹配全尺寸封堵、高效携带悬浮钻屑、强力润滑减阻等优点,同时将漏失速率控制在2 m3/h以下,保证储层渗流通道畅通.通过应用该钻井液,五分支水平井段(长度分别为1 050、1 050、1 012、965和828 m)的纯钻时间为624h,平均机械钻速为7.5 m/h,该分支井的钻井周期为32 d,比设计周期(60d)缩短了28 d.

Fuzzy Ball Drilling Fluid Technology in CBM of Multilateral Horizontal Well FL-H2-L with Five Branch Holes

The multilateral horizontal well FL-H2-L is located in Erdos Basin,with the pay zones of Shanxi group 3#,4#and 5* coal beds.In the first two intervals,bentonite drilling fluid,air and fresh water drilling fluid are applied each,inthe third interval,the clay-free fuzzy ball drilling fluid is applied.The formulation of that is Fresh water,Fuzzy generatedagent (0.3%-0.4%),Layer generated agent (1%-1.5%),Layer strengthened agent (0.2%-0.3%),Gas-core generated agent(0.1%-0.5%),Membrane generated agent (0.1%-0.5%).By using the fuzzy drilling fluid,the loss rate can be controlledwithin 2 m3/h,and the density covers from 0.90 g/cm3 to 0.98 g/cm3,the viscosity is from 30 seconds to 50 seconds.In thiswell,each length of the five branch holes are 1,050 m,1,050 m,1,012 m,965 m and 828 m,the whole net drilling time is 624hours,the average ROP is 7.5 m/h,and the drilling period is reduced from 60 days to 32 days compared with designed.