影响深井和越深井钻速的主要原因分析

ANALYSIS OF MAIN FACTORS AFFECTED PENETRATION RATE OF DEEP AND ULTRADEEP WELLS

谭春飞 李树盛

Tan Chunfei Li Shusheng

石油大学北京石油工程系

由于深井、超深井地质情况不明,地质预告不准等原因,钻井过程中遇到的诸多复杂情况,使钻井速度大大下降。为此,分析了影响深井和越深井钻速的主要原因,认为:1.由于地质因素和井身结构设计不合理造成复杂情况影响钻速;2.国产大尺寸钻头结构单一,型号少,不能满足深井段地层岩性变化的需全;3.破岩机械能量不足;4.水力能量不足,井底岩屑清除不净;5在易斜地区,为了控制井斜被迫采用小钻压吊打;6钻井液性能及井眼净化不好,造成井下复杂情况;7深部致密硬塑性泥页岩地层难钻,造成钻速低;8.小井眼钻井装备不配套,影响深部小井眼钻速。

Resulted from unknown geology in deep and ultradeep wells and inaccurate geological prediction, numerous problems encountered during drilling have caused significant decline of penetration rate. The analysis of main factors affected penetration rate in deep and ultradeep wells indicates that:1. the problems resulted from geologic factors and improper wellbore structure affect penetration rate; 2. less choice in available structure and type of large size home made bits precludes from adapting to lithology variation in the deep inter-vals; 3. inadequate mechanlcal power for rock breaking; 4. inadequate hydraulics to remove bottomhole cutting completely; 5. it is force to fan the bottom with less weight on bit for de-viation control in devi8tlon prone area; 6. poor dril1ing fluid property and inadequate borehole cleaning cause wellbore problems; 7. the tight and hard plastic shale in deep formation is dif-fi cult to drilling, resulting in low penetration rateI 8. the drilling equipment for slim hole is not completed, affecting the penetration of deep slim hole.

10.3969/j.issn.1000-7393.1998.04.006