Impact of Tailored Plunger Lift Solution on Unconventional Well – Middle East Case

Abstract

Plunger Lift systems (PLS) have been proven to be successful for decades in North America and extended into traditionally lower productivity well areas. As well production declines and the flowing bottomhole production increases, the velocity required to remove the accumulated liquids from the wellbore falls below critical velocity, therefore requiring the application of a deliquification method. This project aimed to study an unconventional well for plunger lift solution with challenging mechanical conditions and harsh downhole environment. In unconventional areas, selecting the proper Artificial Lift System (ALS) needed to produce huge gas reserves comes with technical challenges. A field case study is provided to review the selected horizontal well for a plunger lift solution with mechanical ID restriction in a currently ongoing full field development for an unconventional reservoir in Middle East. For the operating company, the original plan was to operate it with rod lift system. However, when the liquid production is not too large (<200 Bbl/d) and there is sufficient gas volume and pressure, plunger lift should be evaluated first, therefore postponing the rod lift installation. This paper will describe the process and results of installing a Tapered Progressive Plunger Lift (TPPL) solution in a horizontal with 5,000-ft lateral and downhole temperatures around 300°F. The existing completion design included a casing size reduced from 5-1/2″ to 4-1/2″ and subsequently designed with a reduced tubing string size as well, from 2-7/8″ to 2-3/8″, representing a mechanical restriction of the Internal Diameter (ID) profile. The tailored plunger lift solution was implemented allowing the packered well with a tapered tubing string design to unload liquids in the wellbore without having to pull the tubing. This was accomplished by adapting the PL installation with a tapered Intermediate landing assembly seating at the tubing crossover. This arrangement not only help counteracted the liquid accumulation of each tubing section but also extended the life of the well by minimizing the condensate to oil ratio and water to oil ratio. A secondary benefit was to fine tune the material selection of the downhole equipment for the harsh reservoir environment. The approach used to enable the adequate selection of the ALS will be described by detailing benefits and results of the TPPL application that have efficiently and economically added value to the unconventional well. In a long-term perspective, the implementation of the Tailored Plunger Lift Solutions can adapt successfully to other wells within the area where these types of completions are commonly use thus helping the full development of green unconventional fields.