SAGD Well Flow Control with Converging-Diverging Choke
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Steam Assisted Gravity Drainage (SAGD) systems, existing flow control devices fail to effectively exclude steam while allowing subcooled fluids to pass through, leading to steam breakthrough and inefficient fluid recovery.
Innovation Solution
A downhole flow control configuration featuring a converging-diverging flow path that preferentially passes fluids with higher subcool status and an elongated helical flow path producing a pressure drop, minimizing steam passage and maximizing fluid recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing flow control devices are used in SAGD systems, then fluid flow control is provided, but steam breakthrough occurs and steam cannot be effectively excluded while allowing subcooled fluids through
Solution Approach 1:
The flow control device incorporates a phase-selective choke that provides different flow characteristics for different fluid phases. The choke geometry is specifically designed to restrict steam flow while allowing subcooled liquid to pass through, creating local quality differences in flow resistance based on fluid phase and subcool status.
Solution Approach 2:
The device utilizes changes in fluid parameters (temperature, subcool status, phase) to differentiate between steam and subcooled liquid. By monitoring these parameter changes as fluid passes through the choke, the device dynamically adjusts or selects flow paths to exclude steam while permitting subcooled fluid passage.
2Object-affected harmful factors
If a flow control device excludes steam effectively, then steam breakthrough is prevented, but fluid flow restriction increases
Solution Approach 1:
The diverging section is designed with specific geometry that creates different pressure recovery characteristics for different fluid types. Subcooled liquid experiences minimal restriction and full pressure recovery, while steam experiences restriction that prevents breakthrough. This local quality differentiation in the diverging section resolves the contradiction between steam exclusion and fluid flow maintenance.
3Object-affected harmful factors
If a converging-diverging flow path is used to preferentially pass subcooled fluid, then steam breakthrough is reduced, but pressure loss occurs in the converging and throat sections
Solution Approach 1:
The device converts the pressure loss that occurs in the converging and throat sections into a beneficial selective restriction mechanism. The pressure drop across these sections creates conditions that further differentiate steam from subcooled liquid flow, with steam experiencing disproportionate restriction. The harmful pressure loss is thus transformed into an additional mechanism for steam exclusion.
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
The configuration effectively excludes steam while allowing subcooled fluids to pass through, minimizing restrictions on high subcool fluids and maximizing fluid recovery by recovering pressure lost in the converging section and producing an adjustable pressure drop in the helical flow path.
Implementation Method 1
a diverging section that recovers fluid pressure lost in the converging section and the throat section
Implementation Method 2
an elongated helical flow path connected to the outlet of the converging-diverging flow path, the helical flow path producing a pressure drop in a fluid flowing therein during use
Data Source
AI summary
A downhole flow control configuration including a housing, a converging-diverging flow path in the housing. The flow path includes a first portion including an inlet, a converging section, and a throat section. The first portion preferentially passes a portion of a fluid having a greater subcool. The converging-diverging flow path further includes a second portion comprising a diverging section that recovers fluid pressure lost in the converging section and the throat section, and an outlet and an elongated helical flow path connected to the outlet of the converging-diverging flow path, the helical flow path producing a pressure drop in a fluid flowing therein during use.