低伤害钻井液技术在义北油区的应用

针对胜利油田义北油区大43区块储层特征,在低渗透油气藏"协同增效"钻井液体系的基础上,开发了一种低伤害钻井液技术。研制的油层保护剂AMP-2封堵性强,稳定性好,放置30 d不分层;防水锁剂FCS抗低温能力强,在-20℃不分层;形成的低伤害钻井液体系FA砂床侵入深度仅为4.0 cm,高温高压砂床侵入深度为5.2 cm,封堵性能强,滤液表面张力为22.1 mN/m,可有效减少水锁损害,渗透率恢复值不小于90%,油气层保护效果好。通过在4口井进行现场试验表明,该低伤害钻井液体系的性能稳定,易于维护,平均钻井周期缩短11.73 d,油层保护效果明显,投产后均不需酸化压裂,投产自喷,平均日自喷量为7.88 t/d。该低伤害钻井液在义北油区大43区块的应用,为今后胜利油田老油区开发提供了较好的借鉴意义。 

Application of Low Damage Drilling Fluid in Yibei Area

A low damage drilling fluid has been developed to protect the low permeability reservoir in the Block 43,Yibei,Shengli oilfield.The development of the new drilling fluid is based on a "synergistic effect" of a drilling fluid for use in drilling low permeability reservoirs.AMP-2,a reservoir protection agent for the new drilling fluid,has strong plugging capacity and good stability;no settling has ever been found after standing for 30 days.FCS,a water blocking agent,does not settle at low temperature to -20℃.Invasion depth of the new drilling fluid on FA sand bed is only 4.0 cm,and on HTHP sand bed this invasion depth is 5.2 cm.The low surface tension of the mud filtrates is 22.1 mN/m,which is efficient in minimizing the damage caused by water block.Recovery of permeability is greater than 90%,an indication of good reservoir protection.Application of this drilling fluid technology on 4 wells reveals that the drilling fluid has stable performance,its properties easy to maintain,and average drilling time reduced by 11.73 days.Wells drilled with this drilling fluid do not necessitate acidization and fracturing,and flow at first production.The average flowing production rate has been 7.88 t/d.This drilling fluid has been successfully used in the Block 43,and the practices are of importance for the development of old oilfields in Shengli area.