Modular Gas Lift System for Offshore Well Unloading
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Solution Overview
Problem
Conventional artificial lift methods for hydrocarbon wells, such as gas lift and well unloading units, face challenges in offshore environments due to high costs, space limitations, and inefficiencies, particularly in managing produced gas which is often vented to the atmosphere, leading to both environmental concerns and lost revenue opportunities.
Innovation Solution
A modular well unloading unit and compressor system that separates produced fluids into liquid and gas, compresses the gas for re-injection into the well to enhance lift performance, and uses a pump to increase liquid pressure, creating a closed loop gas lift system that reduces backpressure and captures vented gas for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas lift is used to enhance lift performance, then liquid rates and reserves increase, but high pressure gas is required which increases cost and device complexity
Solution Approach 1:
The patent combines the gas separation function and gas compression function into a single integrated unit. The separator separates produced fluids into gas and liquid phases, and the compressor immediately compresses the separated gas for re-injection, eliminating the need for separate surface compression equipment and reducing overall system complexity and cost.
Solution Approach 2:
The compressor is designed to serve multiple functions: it compresses gas for gas lift operation, and the same compressed gas is used for well stimulation and pressure maintenance. This multi-functionality reduces the need for dedicated equipment for each function, thereby reducing device complexity.
2Reliability
If a gas lift compressor is installed to provide stable gas supply, then pressure regulation is achieved, but the cost exceeds US$ 2 million and the unit becomes immobile
Solution Approach 1:
The patent segments the gas handling system into modular components: a separator unit and a compression unit that can be integrated but are functionally distinct. This modular approach allows for more cost-effective manufacturing and installation compared to a single large-scale compressor system, while maintaining reliable gas supply through the coordinated operation of separated functions.
Solution Approach 2:
The system uses the previously vented produced gas itself as the resource for gas lift, eliminating the need to import external high-pressure gas. The separator and compressor work together to process this available gas resource, making the system self-sufficient and avoiding the need for expensive external gas supply infrastructure.
3Reliability
If a gas lift compressor is installed to ensure stable gas supply, then pressure can be regulated, but the footprint occupies large deck space on offshore platform
Solution Approach 1:
The patent merges the gas separation and compression functions into a single integrated unit that occupies minimal deck space. By combining these functions rather than having separate large-scale equipment, the system achieves reliable gas supply while minimizing the footprint on the offshore platform deck.
Solution Approach 2:
The system transitions from horizontal space occupation to vertical integration by stacking functional components vertically within a compact footprint. The separator and compressor are arranged in a vertical configuration that maximizes space utilization and minimizes the horizontal deck space required, allowing reliable gas supply without occupying large platform area.
4Productivity
If conventional well unloading unit is used to reduce backpressure, then flow up the well to surface is enabled, but produced gas is vented to atmosphere causing environmental concern and lost revenue
Solution Approach 1:
The patent converts the previously harmful effect of gas venting into a beneficial resource by capturing the produced gas through the separator and using it as the gas source for gas lift operation. What was previously wasted and harmful to the environment is now transformed into a useful resource that enhances well productivity and reduces emissions.
Solution Approach 2:
Instead of discarding the produced gas to the atmosphere, the system recovers it through the separator unit. The recovered gas is then compressed and re-injected into the well for gas lift, creating a closed-loop system that eliminates gas flaring or venting while maintaining productive flow rates.
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 system enhances hydrocarbon production by reducing backpressure and reusing vented gas, increasing production rates and reserves while being cost-effective and space-efficient, with the added benefit of reducing greenhouse gas emissions and allowing for mobility between platforms.
Implementation Method 1
an unloading unit that is configured to receive a produced fluid having hydrocarbons from the well via a production tree and separate the produced fluid into a liquid fluid and a gas fluid
Implementation Method 2
A compressor in fluid communication with the unloading unit is configured to receive the gas fluid from the unloading unit and compress the gas fluid to a predetermined pressure
Implementation Method 3
A pump is configured to receive the liquid fluids from the unloading unit, increase the fluid pressure of the liquid fluid, and deliver the liquid fluid to a pipeline
Implementation Method 4
Gas lift involves the process of injecting gas at high pressure into the annulus of a well... The gas enters the production tubing several thousand feet below the surface through a check valve and has the desired effect of reducing the fluid gradient in the tubing and thus lowering the wellbore flowing pressure
Data Source
AI summary
A system for producing hydrocarbons from a well includes an unloading unit that receives fluids from a wellhead. The unloading unit separates the oil and gas, and the oil is pumped to a pipeline. Using the unloading unit and the pump helps to reduce the pressure at the wellhead which helps increase production. The gas separated by the unloading unit is compressed and re-injected into the well to create a gas lift which further helps increase production. Capturing and reinjecting the separated gas for gas lift operations reduces environmental damages associated with conventional unloading unit and pump assemblies. The unloading unit, compressor, and pump are modular for quicker installation and a smaller footprint. After increasing the productive life of a first reservoir, the system can be broken down and reassembled for use at another reservoir.