Gas Well Inflow Detection Using Liquid Carrier Tracers
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Solution Overview
Problem
In gas wells, tracers used to mark influx zones face a challenge as their affinity to the fluid decreases when the fluid changes phase to gas, causing them to attach to well walls or tubing, leading to poor tracer distribution and inaccurate mapping of influx zones.
Innovation Solution
A method involving pumping a liquid with affinity to tracers into the well, producing the liquid, and consecutively sampling it to detect and measure tracer concentrations, which helps in mapping influx zones and controlling gas production by analyzing the samples to identify and control influx zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tracers are placed in gas wells to mark influx zones, then zone identification capability is improved, but tracer affinity to fluid decreases when fluid changes phase to gas, causing tracers to attach to well walls or tubing
Solution Approach 1:
The patent introduces a liquid carrier as an intermediary substance that transports tracers through the gas well. The liquid carrier has high tracer affinity and maintains tracer suspension even when the well fluid is in gaseous state, preventing tracer attachment to well walls or tubing. This mediator resolves the contradiction by decoupling tracer transport from direct gas-phase interaction.
Solution Approach 2:
The patent changes the physical state parameter of the tracer delivery system by introducing liquid-phase tracer carriers instead of relying on gas-phase tracer transport. This parameter change ensures tracers remain suspended and follow the fluid flow, preventing loss to well walls while maintaining zone identification capability.
2Loss of information
If tracers are used in gaseous state to map influx zones, then zone mapping capability is improved, but tracer distribution becomes poor due to attachment to well components
Solution Approach 1:
The liquid carrier acts as an intermediary that prevents direct contact between tracers and well wall surfaces. By maintaining tracers in suspension within the liquid carrier, the system prevents tracer deposition on well components while ensuring complete tracer transport to the surface for analysis.
Solution Approach 2:
The patent changes the transport medium from gas phase to liquid phase, fundamentally altering tracer behavior. In the liquid phase, tracers remain suspended and follow flow patterns accurately, preventing loss to well walls and ensuring complete tracer recovery for influx zone mapping.
3Reliability
If liquid is pumped into the well to transport tracers, then tracer following capability is improved, but additional equipment and operational complexity are required
Solution Approach 1:
The liquid carrier system serves multiple functions simultaneously: it transports tracers reliably, maintains tracer suspension, prevents tracer loss to well walls, and provides a medium for tracer concentration measurement. This multi-functionality justifies the additional system complexity by resolving multiple tracer-related problems with a single approach.
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 method effectively maps and controls gas production by ensuring tracers follow the fluid, providing accurate influx zone identification and optimizing gas production by controlling valves and potentially stimulating or fracturing zones for enhanced output.
Implementation Method 1
filling the gas well form the surface, through the well head (b) with liquid (v) wherein the tracers (tr1, tr2, tr3, . . . ) have affinity (a) to the liquid (v)
Implementation Method 2
producing liquid (v) form the well (1), consecutively sampling samples (s1, s2, s3, . . . ) from the produced liquid (v)
Implementation Method 3
the tracers (tr1, tr2, tr3, . . . ) have affinity (a) to the liquid (v)
Data Source
AI summary
A method for detecting or mapping potential influx zones for gas from a geological formation to a gas well with a well head with a valve tree or a choke includes the following steps of: marking the potential influx zones with tracer systems with corresponding unique tracers—filling the gas well form the surface, through the well head with liquid wherein the tracers have affinity to the liquid, producing liquid form the well, consecutively sampling samples from the produced liquid, to analyze the samples to prove possible presence of one or more tracers or even measure the tracers concentrations. By performing the method, one may prove possible influx of a back flow of liquid from the influx zones that one assumes implies the gas pressure and the inflow of a gas form the influx zones.