Haseeb Janjua
ProLiftCo
The temperature allocation along the well plays a crucial role in the design performance and troubleshooting analysis of gas-lifted wells. The temperature of injection gas at each valve depth should be well-known to establish the gas flow rate spread across every valve. As gas temperature across the valve and production fluid temperature will be utilized to evaluate nitrogen pressure inside the bellow of the valve. Therefore, the temperature is the main factor in evaluating nitrogen-charged gas lift valve closing and opening pressures.
In this case study, real-time measurement of temperature pressure is done through the RTD Quartz sensor in a flowing gas lift well through a wireline. It has a completion with the 2-7/8” tubing in 5-1/2” casing with a packer, with 8 12 port IPO gas lift valves in conventional mandrels with a chemical screen below that. The new survey measured temperature and pressure across each valve in the current flowing condition are lower than the temperature used in calculating Pvc (gas closing pressure at depth) and OP (valve opening pressure at depth) of each gas lift valve. The new temperature was used to evaluate the temperature correction factor, which is then used to update Pvc and OP to justify that every gas lift valve will have new surface controls (surface opening: Pso and surface closing pressures: Psc).
Once the error in the Dome/bellows pressure originated by estimating a temperature profile lower than the actual value is evaluated, we simulated the error caused by over-estimation of the temperature profile so that we can be ready for wells with higher water cut and high liquid velocity. The accurate temperature measurement at each valve eliminated the prediction process of injection gas and valve temperatures through Shui’s correlation. Also, it helped in finding favorable conditions to prevent paraffin, asphalt, hydrate, and scale creation in late times in the production tubing.
A systematic approach of updating the surface closing and opening pressure gives operational insights into what was wrong with the gas lift operating envelope. Adjustments were made to pressure production traverse curves based on new conditions using GLDP (gaslift design program). After implementing new conditions backed by the well’s data, the production of the well improved and prevented a possible work-over job.