CAJ | 학술논문

定向井由于受诸多因素影响，其实钻轨迹有时并不沿着设计轨道钻进，给钻井施工带来很大挑战。不考虑地层特性、钻井参数、井眼轨迹等影响因素，采用简单实用且可满足工程要求的公式，计算和分析了单弯单稳螺杆钻具组合的理论几何造斜率。研究了井眼及钻具尺寸对造斜率的影响，发现相同条件下小井眼比大井眼更易获得高造斜率。由此提出在造斜率要求较高的井段，可先钻一个小尺寸导眼，再扩眼到设计尺寸的组合钻进模式。以X井为例，证实了在轨迹控制困难的定向井中，采用该组合模式后，满足工程要求且降低作业成本，缩短钻井周期。研究结果为井身结构设计和定向井轨迹控制提供了理论指导和借鉴。
정향정유우수제다인소영향，기실찬궤적유시병불연착설계궤도찬진，급찬정시공대래흔대도전。불고필지층특성、찬정삼수、정안궤적등영향인소，채용간단실용차가만족공정요구적공식，계산화분석료단만단은라간찬구조합적이론궤하조사솔。연구료정안급찬구척촌대조사솔적영향，발현상동조건하소정안비대정안경역획득고조사솔。유차제출재조사솔요구교고적정단，가선찬일개소척촌도안，재확안도설계척촌적조합찬진모식。이X정위례，증실료재궤적공제곤난적정향정중，채용해조합모식후，만족공정요구차강저작업성본，축단찬정주기。연구결과위정신결구설계화정향정궤적공제제공료이론지도화차감。
Directional wells are affected by a number of factors. Their actual drilling trajectory sometimes is not along the designed track, posing great challenge to drilling operation. This paper does not take into account the inlfuencing factors like formation properties, drilling parameters and wellbore trajectory, but uses simple and practical formula which also satisifes the engineering requirement to calculate and analyze the theoretical geometric build-up rate by combination of single-bend, monostable screw drill assembly. The paper studies the effect of wellbore and drillstring size on the build-up rate and ifnds that high build-up rate can be obtained more easily in small hole than in large hole under the same conditions. Hence, it is suggested that a small hole may be drilled ifrst where high build-up rate is required, then reaming to the designed size with the combined drilling mode. Take Well X as an example, in directional wells where borehole trajectory is hard to control, the combined drilling mode can meet the engineering requirement, reduce drilling costs and shorten drilling cycle. The research results provide theoretical guide and reference for the design of wellbore conifguration and control of directional well trajectory.