Analysis of the Effects of Water-absorbing and Recrystallization of Glauberite on Intra-salt Reservoir

The severe salt-deposition in intra-salt reservoir has great influence on the production and stimulation effects at later development stage. In order to study the salt deposition mechanism of the reservoir minerals, physical-modeling experiments have been conducted indoors. The study results demonstrated that during the formation of intra-salt reservoir, water had been discharged continuously. When water passed the glauberite mineral, water-rich crystalline substances formed under high temperatures and high pressures, which obstruct the infiltration flow channels, resulting in the high closure property of the reservoir and disconnectedness of pore holes. During the oil production, the upper and lower salt formations can be interfered during stimulations, wriggle and deformation might occur. After the water-based stimulation fluids dissolve the salt and flow toward the wellbore, crystalline substances formed near wellbore due to thermal and piezometrical changes, which might influence the regular production in oil wells.