Improve Production in Unconventional Oil Wells Using Artificial Sump Pumping System

Abstract

Abstract Unconventional oil wells represent a combination of challenges to electrical submersible pump (ESP) systems and can limit the production potential for those types of wells. Unconventional wells with steep decline curves and high amounts of free gas challenge the operating envelop of current ESP systems to economically and reliably produce these wells. The challenges that unconventional wells present for all forms of artificial lift forms are: (a) highly deviated wellbore; (b) high gas-to-oil ratio (GOR); (c) gas slugs; and (d) tight casing. When a large amount of free gas is present in the production fluid, the gas enters the ESP pumps and drastically affects its performance. In many cases the gas can lock the pump, leading to a production cut. This paper discusses a case history for an unconventional field where traditional ESP methods were used as the primary form of lift. The challenges in using this form of lift to economically produce from those wells are also discussed. The use ofan artificial sump pumping system in unconventional oil wells with steep decline curve and high amount of free gas has a proven record of operating reliably and economically under unconventional wells challenges. Artificial sump pumping systems are configured and designed to fit inside 7-in. casing and bigger to tight casing sizesof 5½ in.through the use of slim-line ESP systems. The artificial sump pumping system uses an inverted shroud to naturally separate gas and block it from entering the pump. This blocking actionprevents the pump from experiencing gas lock due to unpredicted gas slugs. In addition, the system is equipped with a recirculation system to continue cooling the motor during gas slugs, enabling the ESP to continue producing efficiently during slug events. Moreover, a capillary tube could be installed with the system to enhance system run life for wells where corrosion and scale are issues. This paper presents a comparison between the use of conventional ESP methods and artificial sump systems in unconventional, conventional, and mature fields where free gas and gas slugs are a challenge. The results shows how an artificial sump system improves production from those wells and how it significantly improves ESP run life operating under unconventional challenges. In addition, the benefit of using this system for protecting the motor lead extension during installation especially for deviated well and wells with high DLS. This paper discusses how the system reduced the number of failures and enhanced the run life for wells where corrosion and scale-related failures are an issue.