Downhole Water Separation via Tangential Perforations

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Solution Overview

Problem

Current oil well operations face challenges in efficiently separating water from oil at the surface, which can lead to reduced oil production and environmental concerns, as previous solutions often compromise oil production capacity and create environmental hazards.

Innovation Solution

The implementation of a downhole water separation system using tangential perforations and hydrocyclonic flows within the wellbore to separate water from oil, where the emulsion is directed into a rotational vortex, allowing for efficient separation and collection of water at the wellbore bottom, with a propeller agitating the water to suspend debris and a surface pump extracting the treated water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrocarbons and water are separated at the surface using conventional methods, then water can be removed from the production stream, but oil production capacity is compromised and environmental concerns arise

Engineering Contradiction:

Improvewater separation effectivenessVSAvoidoil production capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of separating water from oil at the surface as in conventional methods, this invention inverts the approach by separating water from oil downhole within the wellbore. The tangential perforations create a hydrocyclone effect that forces water to the outer wall and oil to the center, allowing water to be discharged through a dedicated outlet while oil flows upward for production. This inversion of the separation location and mechanism resolves the contradiction by enabling effective water removal without compromising oil production capacity.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If water production is restricted to protect oil production, then oil production capacity is maintained, but water encroachment requires mechanical blocking or chemicals that compromise overall well performance

Engineering Contradiction:

Improveoil production capacityVSAvoidwater control mechanism complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

This invention extracts the water separation function from the oil production stream by providing a dedicated water discharge pathway through the wellbore wall. The tangential perforations and hydrocyclone mechanism separate water and oil in situ, with water being discharged through a separate outlet while oil continues to flow upward for production. This extraction of the water removal function eliminates the need for mechanical blocking or chemical treatments, maintaining oil production capacity while simplifying the overall water control mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If tangential perforations are used to create rotational vortex flow, then water and oil separate efficiently downhole, but the wellbore structure becomes more complex

Engineering Contradiction:

Improveseparation efficiencyVSAvoidwellbore structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

This invention merges the separation function with the existing wellbore structure by using the wellbore wall itself as the hydrocyclone separator. The tangential perforations are integrated into the wellbore casing, and the hydrocyclone flow pattern is created within the wellbore cavity. The separated water is discharged through a dedicated outlet that is part of the wellbore structure, while oil flows upward through the production string. This merging of separation and production functions into a single integrated system achieves efficient downhole separation without requiring separate complex separation equipment.

Inventive Principle:

Principle #5Merging (Combining)

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 enables continuous oil flow without restricting water production, protects downhole equipment, and provides an environmentally friendly method for wastewater disposal by effectively separating and treating water before potential reinjection.

Implementation Method 1

The perforations are tangential to the casing to urge the emulsion into a rotational vortex in the tubular cavity to separate the liquid hydrocarbon from the water. The rotational flow and rotational vortex may involve hydrocyclonic flow.

Methodology Applied

Scientific EffectHydrocyclonic flow: Cyclone Separation

Implementation Method 2

The curvature of the inner surface may direct flow of the emulsion into a rotational flow about a central axis of the tubular cavity

Methodology Applied

Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 3

A propeller disposed in the chamber to agitate water in the chamber, such as to cause debris in the chamber to become suspended in the water in the chamber

Methodology Applied

Scientific EffectMechanical agitation: Stirring

Data Source

PatentUS11136875B2Systems, apparatuses, and methods for downhole water separation

Publication Date: 2021.10.05 SAUDI ARABIAN OIL CO

AI summary

This document relates to systems and techniques for downhole separation of water and oil in oil well operations.