杭锦旗区块漂珠-氮气超低密度泡沫水泥固井技术

为解决杭锦旗区块固井井漏难题，实现水泥浆一次安全上返形成完整水泥环，提高固井质量和保证井筒的完整性，开展了漂珠-氮气超低密度泡沫水泥固井技术研究。在漂珠低密度水泥浆体系中充入氮气，并加入发泡剂和稳泡剂，形成了高压充氮气发泡工艺，设计了密度为1.15~1.20 kg/L的漂珠-氮气超低密度泡沫水泥浆；自主设计研发了机械注氮设备，配套了现场节流加回压装置，形成了超低密度泡沫水泥浆控压防漏固井技术。该固井技术在杭锦旗区块5口井技术套管固井中进行了应用，水泥浆均一次性安全上返。其中，JPH351井井下泡沫水泥浆平均密度为1.15 kg/L，封固段长2 800.00 m，固井质量优良。研究与应用结果表明，漂珠-氮气超低密度泡沫水泥固井技术可以解决杭锦旗及类似区块低压井固井漏失难题。 

Ultra-Low Density Hollow Microspheres-Nitrogen Foamed Cementing Technology in Block Hangjinqi

Hollow microspheres-nitrogen foam cementing technology with ultra-low density could potentially solve the problem of cementing leakage in Hangjinqi Block.It could also assure the one-trip safe return of cement slurry to form a complete cement sheath,and the improve the cementing quality and wellbore integrity.An ultra-low density hollow microspheres-nitrogen foamed slurry with a density of 1.15-1.20 kg/L wad developed by charging nitrogen into the low-density hollow microspheres slurry system,and adding foaming agent and foam stabilizer to form a high-pressure nitrogen-charged foaming technique.The matching field choking and back pressure devices were combined with independently designed and developed mechanical nitrogen injection equipment.By doing so,the foamed cementing slurry technology with ultra-low density for pressure management and leakage control was established.The technology has been used to cement the technical casing in 5 wells in Hangjinqi Block,and in each,the slurry was safely returned one time.The average density of downhole hollow microspheres-nitrogen foamed slurry in Well JPH351 is 1.15 kg/L,the length of cemented section is 2 800.00 m,and both have excellent cementing quality.The successful development and application of ultra-low density hollow microspheres-nitrogen foamed cementing slurry technology has provided a new technical approach for addressing cementing leakage problem of low pressure wells in Hangjinqi Block and similar blocks.