Horizontal wells experience transient flow regimes throughout their long laterals. The average gas/liquid ratio (GLR) produced by a horizontal well may not overwhelm an ESP if the fluids travel in a steady stream. However, gas slugs commonly develop in the lateral section of a horizontal well, growing in size as they approach the heel of the well and move into the vertical section of the wellbore. A well with a pump intake pressure (PIP) of 500 psi at the ESP gauge may have plenty of fluid over the pump intake and still have problems with gas locking the pumps. Even with sophisticated gas handling pumps and gas lock-breaking control algorithms in the variable speed drive (VSD), the ESP still goes down with a gas locked pump.
This paper covers a patent pending technology developed at EOG Resources' Production Technology Center that improves gas-liquid separation of fluids entering an ESP. The tool has been installed in wells with high GLRs, where ESP run times are lower than the field average, and has improved operational stability. This paper follows the development of the technology in the model wellbore at EOG's lab, the design and manufacturing of field trial separators, and the results of several field trials.