二连油田巴38断块保护油层钻井液技术

巴38断块储层物性从中孔特低渗到中孔中渗,非均质性强,属于强水敏、强盐敏地层.针对巴38断块储层特征和现场使用的钾铵基聚合物钻井液体系特点,研究出了适用于巴38断块的油层保护剂L-RP-2.该油层保护剂L-RP-2中引入了中-低分子量聚合物,利用聚合物分子链可以将不同形状和不同粒度的惰性颗粒,包括原井浆中的固相颗粒链接起来共同对储层进行有效封堵.室内评价结果表明,油层保护剂L-RP-2对岩心的封堵效率大于85%,封堵深度小于10 mm,满足了油层封堵技术的要求.加有油层保护剂L-RP-2的保护油层钻井液体系现场应用40口井,在进行测试的15口井中,12口井共计13层表皮系数均小于零,为完善井,3口井表皮系数小于1,为轻微损害井,可见油层保护剂L-RP-2的应用取得了良好的保护油层效果.

Oil reservoir protective drilling fluid technology for Ba38 faulted block in Erlian oilfield

Ba38 faulted block in Erlian oilfield is a reservoir with physical characteristics of intermediate porosity and ultra-low permeability to intermediate porosity and medium permeability, and it is strong water sensitive and salt sensitive in sensitivity evaluation. Also based on using reality of present potassium/ammonium drilling fluid, a reservoir protecting agent L-RP-2 suitable for Ba38 faulted block was studied. In the L-RP-2, a medium molecule polymer was introduced to be a main component, which links or bridges inert particles of different shape and different size in drilling fluid, to work together to seal formation effectively. Lab tests showed that the protecting agent L-RP-2 satisfied requirements of reservoir sealing, the plugged ratio was more than 85% and the invasive depth was less than 10 mm. Oil reservoir protecting drilling fluid with L-RP-2 in has been applied in 40 wells with excellent protection results. Among the 15 wells tested, in 12 wells, skin coefficients of total 13 layers were less than zero, qualifying them completely penetrating wells. In the other 3 wells, the coefficients were less than 1.0, making them slightly damaged wells.