This paper describes an artificial lift case study where ten horizontal Mississippian Lime wells exhibiting high dogleg severity above the tangent section were tested on an electrical submersible pump (ESP) to maximize fluid production. The three main objectives of the test were: (1) to reduce pressure on perforations to an acceptable level; (2) to implement flangeless connections on the equipment string; and, (3) to monitor the economic impact of the installations of the ESP units to the wells.

The challenges for the ESP systems for this specific test included: (i) mechanical damage passing through high dogleg severity (up to 25°/100ft); (ii) quickly declining production; (iii) high gas/liquid ratio (>800 SCF/BBL); (iv) low liquid inflow during gas slugging. These challenges eliminated the possibility of using traditional ESP equipment. Gas-avoidance and gas-separation technology was used to enhance reservoir drawdown, along with flangeless ESP connections, to maneuver the string through the typically equipment-destroying dogleg severity.

This paper describes uncommon techniques to effectively install and operate an ESP unit in highly deviated wells and the application of ESP systems in gassy and gas-slugging wells. Historical design challenges, system-specific design/operation, and production results of the tested wells are also presented. Comparisons to other traditional artificial lift methods, including ESPs with flanged connections, help support the conclusion that it is possible to successfully and economically improve production in a highly deviated unconventional well by using a properly designed ESP. The economic impacts are viewed as positive when the test well results are compared to conventional alternatives that are not adequately equipped to handle all of these challenges.

These results are used to make inferences on potential changes to future wellbore planning and drilling that will impact drilling and completion costs, as well as improved recovery.

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