径向位移对井壁稳定性影响的分析方法  

Analysis Method for Influence of Radial Displacement on Wellbore Stability

作　　者：祁斌[1,2,3] 陈平[1] 夏宏泉[1] 涂君君[4] 

机构地区：[1]油气藏地质及开发工程国家重点实验室西南石油大学,四川成都610500 [2]巴中市发展和改革委员会,四川巴中636000 [3]西南油气分公司油地处,四川成都610016 [4]西南油气分公司工程监督中心,四川德阳618000

出　　处：《测井技术》2015年第1期38-42,共5页Well Logging Technology

基　　金：国家重点基础研究发展计划973项目中国南方海相页岩气高效开发的基础研究专题子课题页岩气水平井钻完井关键基础研究成果

摘　　要：为研究地层岩石在弹性状态下载荷极限和径向位移对井壁稳定性的影响,引入地层弹性载荷系数λ,建立弹性载荷系数和径向位移定量分析模型。该模型证明在井周方位90°和270°处的弹性极限载荷系数和径向位移最小,井壁承载附加应力和抗压力激动能力弱。将该模型应用于蓬莱2井须家河组地层井壁稳定性评价,研究发现,该段地层附加应力场激动时的弹性载荷系数允值应小于1.54,若弹性载荷系数大于1.82则径向位移易发生突变,导致井壁失稳扩径;径向位移下限值自上到下依次增大,井壁抗压力激动能力依次较强;泥岩与砂岩硬夹层径向位移差异较大,两者易产生接触滑动,导致井壁掉块扩径或下钻遇阻。To investigate the influence of rock load limit and radial displacement on wellbore stability, quantitative analysis model for these two parameters using elastic loading coefficient （λ） of the formation has been established. This model shows that at the well circumferential azimuths of 90 °and 270° the elastic loading coefficient and the radial displacement are minima, and the ability that wellbore bears additional stress and resists pressure surges is weak. Application of this model in evaluating the wellbore stability of Penglai 2 well of Xujiahe formation indicates that the permissible value of the elastic loading coefficient should be less than 1.54 when the additional stress field is surging~ if the elastic loading coefficient is greater than 1.82, radial displacement tends to change abruptly, causing borehole instability~ wellbore resistance to pressure surges improves as the lower radial displacement limit increases from the top to the bottom. The difference of radial displacement between mudstone and hard sandstone is large, leading to interlayer slippage, which finally brings about borehole problems, such as borehole enlargement or slacking off.

关 键 词：测井评价 附加应力场 弹性载荷系数 径向位移 井壁稳定性 

分 类 号：P631.84[天文地球—地质矿产勘探]