Abnormal phenomena of ascent speed for build up pressure at fore or latter testi ng period is happened to testing pressure curve at firstly closing well when using P-T packer, shearpin type of packer to conduct straddle test and the reason for these are due to formation reason for interpretation.

The magnitude of surge pressure produced upon shut-in after the well kicks directly decides which shut-in method to be used, soft shut-in, half soft shut-in, or hard shut-in.

on shut-in pressure buildup features,this paper puts forward the method to judge how much difficult the well-control in drilling is by using pressure build up curve of a gas well,then the level of well control difficulty can be determined before well killing.

Taking the downhole closing well as example , this paper gives analysis on the deformation of tubing while testing high pressure wells.