延长油田浅层大位移水平井固井优化技术

Optimization Techniques of Cementing of Shallow Extended Reach Horizontal Wells in Yanchang Oilfield

固井作业是一次性工程,一旦固井质量出现问题,补救作业一般无法达到封固合格的要求,并且水平井固井存在一定的固井工艺难点,包括弯曲井段曲率大,套管不易下入;斜井段套管与井壁发生长段面积的多处接触,井斜越大,摩阻力越大;环空的严重偏心度使窄边钻井液不能有效清除;易形成集中的水带,尤其是水平井游离水易集中与井眼上方,使油气串通;且直井中常用的固井附件不能使用,需要改进或重新设计。延长油田东部的部分区域油层埋深浅、存在低压、易漏失层,该区域内的井在固井过程中易发生地层破裂、水泥浆漏失现象。这不仅使水泥浆返高不够,也对地层造成了污染,严重影响了固井质量和油水井的后续生产。

Cementing job is a one-time project,once the cementing quality problems,remedial cementing opera-tions are generally unable to meet eligibility requirements,and there is a certain level of well cementing cementing process difficulties,including the curved portion curvature,casing under difficult into;inclined casing and the bore-hole wall segments occur long segment of multiple contact area,the greater the deviation,the greater the friction re-sistance;annulus serious eccentricity so narrow mud can not effectively clear;easy to form a concentrate with water especially easy to focus on horizontal wells and above the free water borehole so that oil and gas collusion;and ver-tical wells cementing common attachment can not be used,need to be improved or redesigned. And the extension of the eastern part of the region′s oil reservoir is shallow,there is a low pressure,easy thief zone,the region in the well cementing process prone to the formation fracture,grout leakage phenomenon. This not only makes the grout is not high enough to return,but also resulted in the formation of pollution,seriously affecting the quality of cementing oil wells and subsequent production.