  We present a systematic survey of the temporal and spectral properties of all
GRB X-ray afterglows observed by Swift-XRT between January 2005 and July 2007.
We have constructed a catalog of all light curves and spectra and investigate
the physical origin of each afterglow segment in the framework of the forward
shock models by comparing the data with the closure relations. We search for
possible jet-like breaks in the lightcurves and try to explain some of the
"missing" X-ray jet breaks in the lightcurves.
