摘要
以渤海油田一口大斜度深井在东二下段凝灰岩下套管遇阻,被迫就地固井的复杂情况为例,通过对施工细节、遇阻井段岩性、井眼轨迹、钻井液性能的逐一分析,确定了钻井液密度低是造成下套管遇阻的原因。依托常规井壁稳定模型计算的坍塌压力最高仅为1.40 g/cm^(3),与实际钻井密度调整至1.45 g/cm^(3)仍不能平衡地层的实际情况相差较大。在分析凝灰岩特性的基础上,建立了随时间变化的井壁稳定强度变化模型,计算出钻井时间为10 d时,坍塌压力可达到1.47 g/cm^(3),与钻井实际相吻合。为该区域解决凝灰岩地层坍塌、下套管遇阻等复杂情况提供了密度依据。研究成果也对区域内钻井解决相关复杂情况具有重要意义。
Taking the complex situation that a highly deviated deep well in Bohai oilfield was forced to cementing in situ due to casing obstruction in the lower tuff of the second east section,through the analysis of construction details,lithology of blocked well section,borehole trajectory and drilling fluid performance one by one,it is determined that the low density of drilling fluid is the cause of casing resistance.The maximum collapse pressure calculated based on the conventional wellbore stability model is only 1.40 g/cm^(3),which is quite different from the actual situation that the formation cannot be balanced when the actual drilling density is adjusted to 1.45 g/cm^(3).Based on the analysis of the characteristics of tuff,the variation model of wellbore stability strength with time is established.It is calculated that when the drilling time is 10 d,the collapse pressure can reach 1.47 g/cm^(3),which is consistent with the actual drilling.It provides a density basis for solving the complex situations such as tuff formation collapse and casing running resistance in this area.The research results are also of great significance tosolve the complex problems related to drilling in the region.
作者
郑勋
郑卓
宋峙潮
侯永亮
冯晟
ZHENG Xun;ZHENG Zhuo;SONG Zhichao;HOU Yongliang;FENG Sheng(CNOOC Energy Development Co.,Ltd.,Engineering Technology Branch,Tianjin 300451,China)
出处
《石油化工应用》
CAS
2022年第8期15-19,共5页
Petrochemical Industry Application
基金
中海石油(中国)有限公司深圳分公司重大科技专项“南海东部油田上产2000万吨关键技术研究”,项目编号:YXKY-2019-ZJ-03
中海油能源发展股份有限公司科研攻关项目“水平井控水组合技术应用研究”,项目编号:HFKJ-GJ2018-17。
关键词
凝灰岩
下套管遇阻
钻井液密度
坍塌压力
强度变化模型
tuff
casing running is blocked
drilling fluid density
collapse pressure
strength change model
