The results of a study of oxide precipitates in Czochralski (CZ) grown silicon using two X-ray diffraction methods are reported. The diffuse scattering around the Bragg diffraction maxima was measured on a series of samples after various two-stage annealing treatment. Combining the analysis of diffuse scattering with other experimental techniques we were able to determine mean precipitate size and deformation field around the precipitates. The obtained data show that the deformation field is proportional to the precipitate volume and independent on the annealing temperature or annealing time. The dynamical diffraction in Laue geometry was used to measure precipitate concentration. The results are compared to the selective etching concentration measurement.