Artificial Lift System for Horizontal Wells and Other Wells with Problematic Lift Conditions

Abstract

Artificial lift methods and devices have been a boon to the oil industry since the early days of the industry; however, conventional artificial lift that was designed to be placed in the vertical section is not adequate for wells with significant deviations from vertical. Placing rod pumps and other artificial lift methods in deviated sections are problematic resulting in high operating costs due to down hole failures, high back pressure on the reservoir, and poor liquid lift efficiencies due to gas interference in the down-hole pumps. A new artificial lift method is presented herein that allows a rod pump, or other applicable pump, to be placed significantly above a deviated section while also providing lift for liquids located significantly below the pump. Additionally, the new method provides an improved down-hole gas separator which utilizes a packer type separator system that solves gas interference in wells that have small casing diameters, conventional tubing anchors, high liquid levels, or high gas to liquid ratios. Since reservoir fluids that may contain solids are introduced in the casing annulus above the packer, a specially designed device called a packer shield is installed above the packer to prevent solids from falling on top of the packer and subsequently sticking it in place. All versions of the new method contain a velocity string that extends below the rod pump to improve lift from below the pump to above the pump. One version, designed for wells with sufficient reservoir energy, uses only the velocity string to naturally lift liquids up the velocity string to the pump, while a second version provides relatively low pressure, low volume gas injection to assist in lifting liquids up the velocity string to the pump.