摘要
在实际生产中,套管损坏时的挤毁压力与套管理论抗挤强度相差较大,这表明API规范的套管挤毁压力公式已不能满足实际生产的要求,而考虑套管缺陷的抗挤强度公式,使计算的准确度大幅度提高。目前,对于抗挤强度的研究均以套管呈原始状态、未发生任何变形为前提。但在套管下放后、未固井前,由于套管自由悬持于钻井液中,会受到自身重力、浮力和内外压力的共同作用,因此会发生轴向拉伸和径向压缩。此时套管的抗挤强度较原始状态发生了改变,通过计算可知径厚比较之原始值变大,由此得到考虑套管变形的新抗挤强度公式。新建公式的计算结果与试验结果更为接近,比API公式计算值准确度提高了30%。
In the actual and long-term production,it is known that the actual strength the casing received when it is damaged is much different from the theoretical collapsing strength.So,the classical API collapsing strength formula can not meet the requirements, Dr.Han have studied it and obtained the new collapsing strength formula,and the result is much accurate.Nowadays, most research on collapsing strength is based on that the casing doesn't deform,however,after the casing is set down and before cemented,the casing hanging in a drilling fluid will be stretched axially and compressed radially because of the axial stress caused by its gravity and buoyancy and the radial and circumferential stress caused by its internal and external force.Therefore,the collapsing strength of the casing will be changed.By means of calculating,we know that the radius-thickness ratio is larger than before, and by means of theoretical derivation,we obtain the new collapsing strength formula.The value calculated by the new collapsing strength formula is more reliable to the test data,and it defines the new collapsing strength formula that is more accurate.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2011年第5期104-107,118,共4页
Petroleum Geology and Recovery Efficiency
关键词
套管变形
抗挤强度
轴向变形
径向变形
径厚比
casing deformation
collapsing strength
axial deformation
radial deformation
radius-thickness ration
