Tandem Progressive Cavity Pumps for Deep Well Lift
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Solution Overview
Problem
Progressive cavity pumps (PCPs) are limited in their ability to lift fluids beyond 5,000 to 7,000 feet due to insufficient head, leading to frequent repairs and replacements when dealing with high suspended solid content, increasing production costs and reducing the feasibility of hydrocarbon development.
Innovation Solution
A tandem progressive cavity pumping system is implemented, comprising a first pump at a higher elevation and a second pump at a lower elevation, with the discharge of the first pump connected to the intake of the second pump, allowing for the use of a rod-driven progressive cavity pump and a progressive cavity pump with a downhole electric motor to extend the pumping depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single progressive cavity pump is used, then the pump can operate at lower speeds and handle fluids with suspended solids better, but the pump cannot lift fluids beyond 5,000 to 7,000 feet due to insufficient head
Solution Approach 1:
The system divides the single pump function into two separate progressive cavity pumps operating in tandem. The first pump handles a portion of the lift, and the second pump handles the remaining lift to surface, allowing each pump to operate within its optimal head range while achieving greater total pumping depth
2Length of moving object
If electric submersible pumps (ESPs) are used to lift fluids beyond 5,000 to 7,000 feet, then the pumping depth requirement is met, but the pumps fling suspended solids against the pump housing causing frequent repairs and replacements
Solution Approach 1:
The system segments the pumping function into two progressive cavity pumps that each handle a portion of the total lift, avoiding the need to use ESPs that would require high-speed operation and cause suspended solids to impact the pump housing
Solution Approach 2:
The system changes the operating parameters by using two pumps operating at lower individual heads rather than one high-head pump or an ESP, maintaining the gentle handling characteristics of PCPs while achieving greater total depth
3Length of moving object
If the discharge of the first pump is connected to the intake of the second pump, then the pumping depth is extended beyond 5,000 to 7,000 feet, but the device complexity increases
Solution Approach 1:
The system uses two separate pump units that can be individually maintained and replaced, distributing the complexity across modular components rather than a single complex high-head pump system
Data Source
AI summary
A tandem progressive cavity pump system lifts well fluids from a production zone to a well surface. The system provides a first pump and a second pump. The system positions the first pump at the production elevation within the well, and the second pump at an intermediate elevation within the well. The system then connects a discharge of the first pump to an intake of the second pump. The system is then operated so that the first pump lifts well fluids from the production zone to the intermediate zone, depositing the well fluids in the intake of the second pump. The second pump then lifts the well fluids from the intermediate zone to the surface of the well.