化学固结承压堵漏技术在明1井的应用

Application of Mud Loss Control with Chemical Solidification LCM in Well Ming-1

明1井是中原油田普光分公司部署在普光区块的1口预探井,该井雷口坡组以上地层由于裂缝发育、断层多、地层破碎、胶结性差,加之钻井液密度窗口窄,多次发生失返性恶性漏失。采用桥堵、可控胶凝、水泥浆、凝胶等多种堵漏方式,均告失败,采用常规承压及雷特承压堵漏方法,但效果均不好。后采用化学固结浆封堵施工井段,采用交联成膜浆保护施工井段以上裸眼地层,防止憋挤时压漏上部薄弱地层,提高了地层承压能力,达到了施工要求,为顺利完成该井的施工任务提供了安全保障。化学固结堵漏材料是一种高价金属离子纳微米级材料,具有微小膨胀功能,密度在1.05～1.90g/cm3之间可调,抗温达180℃;交联成膜浆使用高强度桥接堵漏材料代替常规的桥接材料,并引入化学交联固结材料,抗返吐能力大于3 MPa,抗温大于180℃,抗压差大于20 MPa。该化学固结承压堵漏技术的成功应用,为在易漏地层提高地层承压能力提供了一种有效的堵漏方法。

Well Ming-1 is an exploratory well drilled in Block Puguang by the Puguang subsidiary of Zhongyuan Oilfield Company.Lost circulation has occurred many times during drilling the formations on top of the Leikoupo Formation, where fractures and faults develop. These formations are generally broken, have poor cementation and narrow density windows. Methods of controlling lost circulation, such as bridging and plugging, gels of different composition and properties and cement slurry, all failed. Conventional pressure bearing lost circulation control methods and Neotor pressure bearing lost circulation control method have also been applied,and the lost circulation was not satisfactorily controlled and stopped. A chemical solidification technology was then used to control mud losses, and a cross-linking filming fluid was applied to protect the open hole section above the mud loss spots from being fractured while squeezing. Using this technology, the pressure bearing capacity of the formations was strengthened, providing a safeguard for mud loss control. The chemical solidification lost circulation material（LCM） used was a high valent metal ion nano material, and has the ability of slight swelling. It has density that can be adjusted between 1.05 g/cm3 and 1.90 g/cm3, and is stable at temperatures up to180 ℃. In the cross-linking filming fluid, a high strength bridging LCM was used to replace the conventional bridging LCM previously used, and a chemical cross-linking solidification material was added to the filming fluid. With this chemical cross-linking solidification material, flowback of LCM slurry will not occur at pressures even higher than 3 MPa. This filming fluid remained stable at temperatures up to 180 ℃, and when solidified, can stand differential pressures as high as 20 MPa. The successful operation with this chemical solidification LCM provides an effective way of enhancing the pressure bearing capacity of formation to control lost circulation.