【作者】 刘宏丽；

【导师】 周江羽；

【作者基本信息】 中国地质大学 ， 油气田开发工程， 2004， 硕士

【摘要】 《侧钻小井眼段扩孔技术研究》是提高辽河油田侧钻井生产寿命的关键技术，本文在认真分析辽河油田侧钻井普遍存在的寿命短原因的基础上，结合国内外小井眼钻井经验，针对侧钻小井眼环空间隙小、套管难以居中、固井质量差等难题开展研究，从理论研究方面，主要研究侧钻小井眼合理环空间隙和扩孔技术，优选了φ152.4mm和φ118mm井眼环空间隙。通过对侧钻小井眼环空间隙优选技术进行了分析研究，得出主要结论为增大水泥石的抗压强度是提高水泥环及套管承载能力的较好方法，并且考虑水泥石悬挂套管的能力、密封性能和保证其两相液体的驱动效果，即水泥石既要有较高的抗压强度、剪切胶结强度和较低的界面渗透率，又要有良好的顶替效率和较高的承载能力，水泥环的最佳厚度约在1″左右。在研究侧钻井小井眼段扩孔技术的基础上，研制出适合不同地层的侧钻井扩孔工具。并且通过现场试验，又对侧钻井段扩孔工具进行改进和完善，研制成功了φ152.4mm和φ118mm井眼扩孔工具。从试验井扩孔情况看，扩孔工具扩出的井眼均匀连续，消除了由于侧钻过程中井眼坍塌或井壁掉块引起的不均匀井眼(糖葫芦井眼)，有利于固井质量的提高，由于扩孔加大了固井形成的水泥环厚度，提高水泥环的抗冲击能力。水泥环在射孔、修井、采油、蒸汽吞吐等作业中损坏的程度会大大降低，可有效延长侧钻井的寿命，扩孔后的井眼与套管之间的环空间隙较大，注水泥过程中的循环阻力较小，因而减少了由于动压差所引起的钻井液或水泥浆侵入地层的深度，相对减少了钻井液及水泥浆对油层的污染程度，有利于减少对油层的污染，由于扩孔速度快，与钻井过程相比钻井液浸泡时间短，形成的泥饼致密程度差，易于在固井时被冲洗掉，有利于提高第二界面的固井质量，进而减少了因油气水窜而引起的水层对油层的压持作用，有利于提高油井产量。通过扩孔技术将侧钻小井眼窄间隙固井转化为宽间隙常规固井，解决了窄间隙固井的难题，φ152.4mm和φ118mm井眼扩孔工具适用于砂岩、泥岩等各种沉积岩地层，现场试验方面，根据扩孔特点，提出了扩孔技术工艺措施，φ152.4mm井眼扩至170-180mm，φ118mm井眼扩至140-150mm，最浅井深875m，最深井深2935m，所扩井眼连续平滑，扩孔后小井眼的固井施工状况得到明显改善，固井优质率达到90％以上。据国外有关资料介绍，侧钻井扩孔后平均可延长寿命30％以上，油田开发中后期，侧钻井是老区挖潜、稳产的最重要手段，而扩孔技术是提高侧钻井寿命的最有效的技术之一。更多还原

【Abstract】 "A Study on Sidetracking Slim-hole Reaming " is a key technique to improve the longevity of the sidetracking wells in Liaohe Oilfield. This paper illustrates the study on the problems of small annular clearance, casing centralization and poor cementing existing in the sidetracking slim-hole by analyzing the reason for the short life of the sidetracking wells as well as by combining the slim-hole drilling experiences both at home and abroad. Theoretically, the proper annular clearance and reaming process for the sidetracking slim-hole are discussed, and the preferred clearance of φ152.4 mm and φ118 mm is finalized. The analysis on annular clearance optimization showed that increasing the compressive resistance of cement was a better way to improve the bearing capacity of cement sheath and casing. Considering the hanging ability, seal performance and two-phase fluid driving efficiency of the cement, that is, not only should the cement have high compressive resistance and shear bonding strength, and low interface permeability, it should also have good displacement efficiency and high bearing capacity, the optimal thickness of the cement sheath should be around 1". On the basis of sidetracking slim-hole reaming study, the slim-hole reaming tools which are suitable for different formations are developed, and they are further improved and perfected through field test, φ152.4 mm and φ 118 mm reaming tools are developed. The borehole reamed by the reaming tools is uniform and successive, which eliminates the non-uniform borehole caused by hole collapse during sidetracking operation, improving cementing quality. As for the reaming hole increases the thickness and improves the impact resistance of the cement sheath, the damaging degree is greatly decreased during perforation, workover, production and steam stimulation, prolonging the life time of the sidetracking wells. After reaming, the big annular clearance between borehole and casing as well the less circulating resistance will contribute to decreasing invasion depth of the drilling fluid and slurry, therefore, formation damage caused by drilling fluid and slurry is also reduced. Compared with drilling, reaming operation will shorten the drilling fluid soak time because of the rapid reaming process, as a result, the formed mud cake is less consolidated and is much easier to be washed out during cementing, therefore the second interface cementing can be improved, also the hold down pressure of water applied onto reservoir will be reduced, improving the well productivity. The narrow clearance cementing problem is solved by changing the slim-hole narrow clearance into wide clearance conventional cementing. φ152.4 mm and φ118 mm reaming tools are suitable for the sedimentary formation such as sandstone and shale. In the field test, a new reaming technique is recommended according to the borehole characteristic, that is, φ152.4 mm borehole is enlarged to 170-180mm, φ118 mm to 140-150 mm, the minimum well depth is 875m, and the maximum depth is 2935m, all the reaming holes are successive and smooth. After reaming, the slim-hole cementing is greatly improved, with thepremium rate of more than 90%. According to the information abroad, the average life time of sidetracking wells after reaming can be prolonged by 30%. In the middle or late period of the field, the sidetracking wells are critical to improve the development potential of old blocks and keep stable production, while the reaming technique is the most effective technique to prolong the longevity of the sidetracking wells.更多还原