The contraction force will be produced in unsetting of hydraulic packer by lifting tubing string because of effect pressure and pumping and so on. 采用上提管柱解封的液压式封隔器管柱，由于压力效应及泵抽等因素影响，将产生一定的收缩力。
The paper introduces a new type slim - hole MWD tool, which is capable of accurately measuring downhole annular pressure and pressure effect caused by swabbing and waveness. 文章介绍一种新型小井眼随钻测井仪，它能够精确测量井底环空压力以及抽吸和波动引起的压力效应。
