江汉盐湖盆地套管损坏原因分析

本文针对江汉油田开发中过多,过早的发生套管损坏的问题。根据大量套管损坏井的实际资料,运用聚类分析方法和塑性流动理论,结合江汉盐湖盆地的地质特征,参考有关文献,指出当岩盐等可塑性岩类埋藏达到一定深度时,其上覆地层的重力载荷压力,在差异人作用下,使岩盐产生相当于上覆地层平均每米深度0.24公斤/厘米²的塑性流动压力。所形成的侧向挤压应力,超过套管抗挤负荷,是造成江汉油田套管过多、过早损坏的主要原因。并提出将岩盐井段的套管抗挤系数提高到0.24公斤/厘米²/米,作为防止套管损坏的主要措施。这对具有岩盐等可塑性岩类的油田或地区具有一定参考价值。

CAUSES OF CASING FAILURE IN THE JIANGHAN SALT-LAKE BASIN

From analyses of a large amount of well data and application of the theory of plastic flow with reference to the geologic features of the basin, the cause of frequent premature casing failure in the Jianghan salt-lake basin is studied. It is pointed out that when a plastic rock like rock salt is buried to a certain depth, the gravity loading pressure of the overburden may, under the action of differentiation, result in a plastic flowing pressure of 0.24 kg/cm² commensurate to that for an average of each meter of burial of the overburden. The author believes that the resulting lateral compression stress in excess of the compression load of casing is the primary csuse of the frequent premature casing failure in Jianghan. He therefore proposes to raise the compressibility coefficient of the casing for the rock-salt section to 0.24 Kg/cm²/meter as a principal preventive measure to be introduced in Jinaghan.