In the Mangala Onshore Oil fields, water mixed with polymer fluid is injected into the reservoir to enhance production.
The polymer fluid mother solution is pumped from suction headers through positive displacement pumps. Polymer fluid from each PD pump discharge is mixed with injection water in the static mixer and delivered to individual wells. The flow of the polymer fluid mother solution can be set to desired value by varying the RPM of the PD pumps. The water flow is controlled through a FCV upstream of the static mixer to achieve the desired dilution.
Pressure Level Values of the fluids in both Upstream and Downstream models has been referred correspond to the maximum pressure in each pipes.
Excitation Frequency Analysis for Upstream and Downstream model with Polymer fluids.
The comparison of maximum and minimum pressure profiles in Upstream as well as Downstream for two different polymer fluids.
Consequently, pressure variations due to fluid displacement will be proportional to pump speed. Therefore, designing case which will lead to the higher pressure variations is defined with a pump operated at maximum speed.
The solution is to install the pulsation dampener or the surge suppressor. They are the most effective choice and a cost efficient way to prevent damage caused by pulsation. The dampener should be installed as close to the pump or quick closing valve and is charged to 85% of the liquid line pressure. It is important to specify the correct pulsation or surge suppressor, and this requires a exact calculation. Pulsation study provides the clear calculation with graphical and visual results to prevent from pulsation and its causes.
The purpose of the pulsation study is to the investigate pressure variations and forces at different locations of the system within the polymer Fluid injection network and also to confirm that the pressure pulsations are within the allowable limits calculated in accordance with API 674. The output of the study will be force vs. time data in order to perform a stress analysis by third party.
Pulsation Study is required to be carried out for three nearly identical injection networks operating at Pressure level of 125 barg.
Step 1: To study the given system and find out the places where pulsation can occur (At design Stage), or get the required details where pulsation occurs (At existing system)
Step 2: System modelling using software.
Step 3: Provide the required details of pump, piping network and all other components in the system.
Step 4: Provide the fluid characteristics, flow and pressure values.
Step 5: Run the model with different features available in software.
Step 6: Evaluate the output values and graphical results.
Step 7: Optimization of system design and operations (Until the pulsating effect are achieved as minimum).
Step 8: Prepare the detail report to client with assessment of design and modifications to resolve the issues.