摘要
针对四川盆地周缘昭通国家级页岩气示范区黄金坝区块2口页岩气水平井套管严重变形的情况,基于24臂井径套管变形测量、裸眼井径、电阻率电测、钻时及气测录井、固井CBL/VDL及CBL成像等资料,分析引起套管变形位置附近地层的地质与工程特征,利用三维成像分析软件分析24臂井径测量数据并进行三维成像,得到了变形套管的形态特征。研究结果表明:(1)极严重套管变形井段发生在构造裂缝发育区;(2)套管变形形态为上下方向为主的"S"形弯曲;(3)极严重套管变形呈现明显的遭受岩石高角度滑移挤压而横向剪切变形特征。据此提出建议:(1)该区应重点防范由岩石沿裂缝面滑移引起的剪切套管变形,利用产层段构造等值线图,设计井眼轨迹避开地下局部高陡构造的"脊部"或"谷底"位置;(2)利用产层段蚂蚁体分布图预测的裂缝带分布信息,使井眼轨迹沿裂缝带走向钻进;(3)推荐采用免钻磨大通径桥塞或全通径无限级完井工艺技术,避开压裂后常规桥塞钻磨工序,以确保压裂后的各级压裂层都能投产。
In the Huangjinba Block of the Zhaotong National Shale Gas Demonstration Zone in the periphery of the Sichuan Basin, two horizontal shale gas wells suffer severe casing deformation. In this paper, the geological and engineering characteristics of the strata around the deformed casing interval were analyzed based on the 24-arm caliper measurement of casing deformation, open-hole caliper, electrical resistivity, drilling time and gas logging, cementing CBL／VDL and CBL imaging. Then, 24-arm caliper measurement data were analyzed and 3D imaged by 3D imaging analysis software, to figure out the morphologic characteristics of deformed casing. It is shown that severe casing deformation tends to occur where structural fractures are developed. Besides, casing deformation is mainly in the form of ＂S＂-shape bending vertically. The severely deformed casing is also characterized by obviously transverse shear deformation caused by the high-angle sliding compression of rocks. Therefore, some suggestions were proposed correspondingly. First, the countermeasures in this block shall focus on shear casing deformation caused by the sliding of rocks along the fracture face. Wellbore trajectory shall be designed based on the structural contours map of pay zones to bypass the ＂ridge＂ and ＂valley bottom＂ area in the local high and steep structural zones. Second, the distribution information of fractured zones shall be predicted based on the ant-tracking attribute volume dis- tribution map of pay zones, so that the wellbore trajectory can run along the strike of fractured zone. And third, it is recommended to use plug-drilling free big bore bridge plug or full-bore infinite stage completion technique, so that the conventional bridge plug milling oper- ation after fracturing can be omitted and each fractured layer can be put into production after fracturing.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2017年第11期91-99,共9页
Natural Gas Industry
关键词
四川盆地周缘
昭通国家级页岩气示范区
24臂井径测量
页岩气井
套管变形
天然裂缝
剪切变形
岩石滑移
工程应对方案
Sichuan Basin
Periphery
Zhaotong National Shale Gas Demonstration Zone
24-arm caliper measurement
Shale gas well
Casing deformation
Natural fracture
Shear deformation
Sliding of rocks
Engineering solution
