Downhole Sand Gas Separation System for Rod Pump Protection

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Solution Overview

Problem

The operating life of rod pumps in hydrocarbon production is reduced due to the presence of sand and gas in production fluids, and existing technologies are inadequate in effectively separating these from wellbore fluids before they are pumped to the surface.

Innovation Solution

A sand and gas separation system comprising an upper separator for gas separation and a lower separator for sand separation, coupled together, which includes a gas plug and a cyclone housing with helically arranged fins to create a vortex for centrifugal separation, allowing sand to be funneled into a tailpipe and gas to be contained in a gas separation annulus within the upper separator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sand and gas are present in production fluid, then the rod pump can pump fluid to surface, but the operating life of the rod pump is significantly reduced

Engineering Contradiction:
Improveoperating life of rod pumpVSAvoidsand and gas in production fluid
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The separation system is divided into two distinct functional segments: a lower separator for sand removal and an upper separator for gas removal. This segmentation allows each component to specialize in removing one type of harmful substance, thereby effectively protecting the rod pump from both sand and gas without requiring a single complex separator that would be less efficient at handling both substances simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separation system performs preliminary removal of sand and gas from the production fluid before the fluid enters the rod pump. By implementing this preliminary action, the harmful substances are eliminated in advance, preventing them from causing wear and operational issues during the pump's normal operation, thus extending the pump's operating life.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If existing separation technologies are used, then some sand and gas removal is achieved, but the separation is inadequate and sand and gas still affect pump operation

Engineering Contradiction:
Improveeffectiveness of separationVSAvoidseparation system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the sand separation function and gas separation function into a single integrated downhole separation system. The lower separator and upper separator are combined in a vertical arrangement within the production string, allowing both separation functions to operate simultaneously in one location. This merging provides comprehensive separation effectiveness while avoiding the complexity of multiple separate systems or post-pump separation equipment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The separation system employs a nested structure where the lower separator and upper separator are arranged vertically one above the other within the production string. The inner tube of the upper separator is positioned within the housing of the lower separator, creating a compact nested configuration that maximizes separation effectiveness within the constrained downhole space.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Productivity

If sand is not separated, then the fluid can flow freely, but sand causes wear and reduces pump efficiency

Engineering Contradiction:
Improvepump efficiencyVSAvoidsand wear
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The lower separator extracts sand particles from the production fluid through centrifugal separation using a spinny separator with helically arranged fins. This extraction process removes the harmful sand component while allowing the cleaned fluid to continue flowing freely to the rod pump, thereby maintaining productivity while eliminating sand-induced wear and efficiency loss.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If gas is not separated, then the fluid can be pumped continuously, but gas accumulation reduces pump performance and can cause operational issues

Engineering Contradiction:
Improvecontinuous pumping capabilityVSAvoidgas accumulation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The upper separator acts as an intermediary device between the lower separator and the rod pump. It receives desanded fluid from the lower separator, separates gas from the liquid phase using a gas plug and gas separation annulus, and delivers degassed fluid to the rod pump. This intermediary separation ensures continuous pumping capability while preventing gas accumulation that would otherwise harm pump performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Effectively separates sand and gas from wellbore fluids, extending the operational life of rod pumps by ensuring that only desanded and degassed fluids are pumped to the surface, thereby reducing wear and increasing production efficiency.

Implementation Method 1

a lower separator configured to separate out sand from wellbore fluids; helically arranged fins to create a vortex for centrifugal separation

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

cyclone housing with helically arranged fins to create a vortex for centrifugal separation

Methodology Applied
Scientific EffectVortex flow: Vortex Ring

Implementation Method 3

an upper separator configured to separate out gas from wellbore fluids; a gas plug disposed in the top sub, wherein the inner tube is coupled to the gas plug; and a gas separation annulus between the inner surface of the top sub and the outer surface of the inner tube

Methodology Applied
Scientific EffectGas-liquid separation: Cyclone Separation

Implementation Method 4

a tailpipe coupled to the lower end of the separator through which sand separated out by the lower separator flows into

Methodology Applied
Scientific EffectGravity flow: Gravitation

Data Source

PatentEP3688278B1Downhole sand and gas separation system for use with a rod pump
Publication Date: 2023.07.12 FORUM US INC
  • EP3688278B1 patent drawingFigure 1~2

AI summary

A sand and gas separation system for use with a rod pump. The system comprises an upper separator configured to separate out gas from wellbore fluids prior to flowing into the rod pump. The system further comprises a lower separator configured to separate out sand from wellbore fluids prior to flowing into the upper separator. The upper and lower separators are coupled together by a mechanical coupling.