Volumetric Pump Pressure Control for Polymer Injection

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Solution Overview

Problem

Current methods for reducing pressure in oil well injection systems, particularly for water-soluble polymer solutions, suffer from mechanical degradation due to shear, which limits the effectiveness of polymer viscosity and mobility in enhanced oil recovery operations, especially in systems with chokes and pumps.

Innovation Solution

Replacing traditional chokes with reversible volumetric pumps controlled by a brake system to manage flow rate and injection pressure, allowing for precise pressure reduction without mechanical shear, using either mechanical or electrical brakes depending on the application, and selecting suitable materials and designs for durability and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If traditional chokes are used to reduce injection pressure, then pressure control is achieved, but mechanical degradation of polymer occurs due to shear

Engineering Contradiction:

Improveinjection pressureVSAvoidmechanical degradation

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical choke system with a volumetric pump system that uses positive displacement mechanics to reduce pressure. The volumetric pump controls flow rate through volumetric displacement rather than through shear-induced flow restriction, thereby achieving pressure reduction without subjecting the polymer solution to damaging shear forces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the operating parameters from high-shear flow conditions in chokes to low-shear volumetric displacement conditions. By controlling the pump's volumetric output and operating speed, the system achieves the required pressure reduction while maintaining polymer chain integrity and solution viscosity.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If pump speed is increased to maintain flow rate, then productivity increases, but injection pressure increases beyond fracturing pressure limits

Engineering Contradiction:

Improveflow rateVSAvoidinjection pressure

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The system dynamically adjusts the volumetric pump's operating speed to match the specific requirements of each well. By varying the pump speed rather than maintaining constant high speed, the system can deliver required flow rates at reduced pressures that stay within fracturing pressure limits for each individual well.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention segments the injection system into individual well streams, each with its own volumetric pump or flow control mechanism. This allows independent optimization of flow rate and pressure for each well based on its specific fracturing pressure characteristics, rather than forcing all wells to operate at uniform high pressure.

Inventive Principle:

Principle #1Segmentation

3Stress or pressure

If choke passage is reduced to control pressure, then pressure reduction is achieved, but flow rate is limited

Engineering Contradiction:

Improvedownstream pressureVSAvoidflow rate

Core Design Contradiction:

Stress or pressureVSSpeed

Solution Approach 1:

Instead of reducing flow rate to achieve pressure reduction (as chokes do), the volumetric pump inverts the approach by directly controlling volumetric displacement to achieve pressure reduction while maintaining or optimizing flow rate. The pump actively manages both parameters rather than passively restricting flow.

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces injection pressure while minimizing mechanical degradation of polymers, maintaining viscosity and enhancing oil recovery efficiency by ensuring precise pressure control across varying well conditions, from offshore to land operations.

Implementation Method 1

a brake system has to be used to control the rate of the volumetric pump

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8807222B2Process for reducing the pressure for injecting a polymer solution into an oil well without shear on said solution

Publication Date: 2014.08.19 S P C M SA

AI summary

A process is provided for reducing the pressure for injecting a solution of water-soluble polymer from a given injection pump into various oil wells in a given field as a function of the fracturation pressure for each well. Between the injection pump and each well, a respective main volumetric pump is placed. The fracturation pressure of each well is detected with a respective manometer, and the flow rate of each volumetric pump is controlled, using a brake, as a function of detected fracturation pressure of the respective well.