Study on dynamic mechanical analysis and creep law of multi-stage segmental subdivision water injection pipe string

Key words:  multi-stage and multi-segment  subdivision water injection  string mechanics  dynamic analysis  creep

Abstract:

In order to accurately analyze the dynamic mechanical properties and creep behavior of multi-stage and multi-segment water injection pipe under different working conditions, a three-dimensional mechanical model of water injection pipe string was established. The three-dimensional trajectory of the wellbore and the spatial force of the multi-stage and multi-segment water injection pipe string were considered. The stress continuity conditions at the packer and the dynamic mechanical properties of the water injection pipe string were analyzed, the creep mechanism of the packer was studied and corresponding suggestions were put forward. The creep analyses were performed under different working conditions aiming at the water injection column of the well H 43-12. The results show that the error range of the creep algorithm proposed was 8％-15％, which possesses a high accuracy. During different conditions, due to the extreme changes of temperature and pressure, the creep of the column is very obvious. The creep variation law of the separator is basically the same with time passing by. Moreover, after the rigid injection of the water injection pipe column, the creep amount of the packer at each level greatly reduces.