Wellbore Crossflow Rate Determination via Nodal Analysis

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Solution Overview

Problem

Existing methods for determining crossflow rates in injection wells are often operationally and economically inefficient, particularly when leaks occur, as they require the use of spinners or flow meters, which can be costly and risky.

Innovation Solution

A method using well performance modeling and nodal analysis to calculate crossflow rates based on surface data during normal operation, without the need for downhole interventions, by generating an injection well performance model and simulating leak conditions to determine the crossflow rate at the leak location.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If spinners or flow meters are used to determine crossflow rates in injection wells with leaks, then measurement accuracy is improved, but operational risk and cost increase

Engineering Contradiction:

Improvecrossflow rate measurement accuracyVSAvoidoperational safety and cost efficiency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent creates a virtual model (copy) of the injection well that replicates its hydraulic behavior. By modeling the well system and using surface pressure data to calculate crossflow rates through the model, the invention eliminates the need to physically deploy spinners or flow meters downhole, thereby maintaining measurement capability while avoiding operational risks and costs associated with downhole interventions

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical measurement system (spinners or flow meters) with a computational modeling system. Instead of using physical devices to directly measure flow rates downhole, the invention uses mathematical models combined with surface pressure measurements to calculate crossflow rates, substituting mechanical measurement with computational analysis

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If downhole interventions are performed to measure crossflow rates, then measurement capability is improved, but mechanical risks and costs worsen

Engineering Contradiction:

Improvecrossflow rate determination capabilityVSAvoiddownhole intervention complexity and risk

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement capability from the downhole environment and relocates it to the surface. By using surface pressure measurements combined with hydraulic modeling, the invention determines crossflow rates without needing to place any measurement devices downhole, effectively taking out the measurement function from the risky downhole zone

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a hydraulic model as an intermediary between surface measurements and crossflow rate determination. The model acts as a mediator that translates easily obtainable surface pressure data into accurate crossflow rate calculations, eliminating the need for direct downhole measurement devices

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10900344B2Determining wellbore leak crossflow rate between formations in an injection well

Publication Date: 2021.01.26 SAUDI ARABIAN OIL CO

AI summary

Techniques to determine wellbore leak crossflow rate between formations in an injection well are described. The techniques repurpose well performance principles to achieve the objective of cross flow rate quantification without the need to run a flowmeter.