Passive Microseismic Monitoring for Reservoir Fluid Phase Identification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods fail to effectively detect and monitor the type of fluid moving along flow pathways in oil reservoirs using passive microseismic emissions, which is crucial for optimizing reservoir management and improving oil recovery.
Innovation Solution
A system and method that utilize passive microseismic data to differentiate between water and oil movement by establishing a baseline of microseismic events during varying water injection rates, allowing for continuous monitoring and identification of fluid pathways and phases, leveraging the higher mobility of water in high-permeability conduits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional seismic monitoring methods are used to detect fluid movement in reservoirs, then general fluid flow can be detected, but the specific type of fluid (water or oil) cannot be differentiated
Solution Approach 1:
The patent applies parameter changes by analyzing variations in microseismic event frequency and magnitude as key parameters. By establishing baseline microseismic activity during water injection and comparing it to periods of normal production, the system detects parameter changes that indicate water breakthrough. This allows fluid type identification without adding complex hardware, resolving the contradiction between measurement precision and device complexity.
2Loss of information
If microseismic monitoring is implemented to track fluid pathways, then fluid movement can be detected, but continuous differentiation between water and oil phases is not achieved
Solution Approach 1:
The system implements feedback by continuously comparing real-time microseismic event rates against established baselines from water injection periods. When the microseismic activity exceeds the baseline threshold, the system provides feedback indicating water breakthrough. This feedback mechanism enables continuous fluid phase differentiation while maintaining monitoring efficiency, as it uses simple threshold comparisons rather than complex real-time analysis.
3Measurement precision
If passive microseismic data is analyzed without baseline comparison, then some fluid movement is detected, but accurate fluid pathway mapping and phase identification cannot be performed
Solution Approach 1:
The patent applies preliminary action by establishing microseismic baselines during water injection periods before normal production resumes. These pre-established baselines serve as reference thresholds for rapid comparison during subsequent monitoring. This preliminary data collection and analysis enables accurate fluid pathway mapping and phase identification during production without requiring time-consuming real-time baseline establishment, thus resolving the contradiction between measurement precision and time loss.
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
Enables accurate mapping of fluid pathways and identification of fluid phases, optimizing injection and production operations, and enhancing overall oil recovery by distinguishing between water and oil flow based on microseismic event frequency and magnitude.
Implementation Method 1
The microseisms result from elastic rock failure of the reservoir rock matrix
Implementation Method 2
The micro-earthquakes are due to shear stress release along zones of weakness in the rock formation
Implementation Method 3
Seismic waves from microseismic events are transmitted from the source location (or hypocenters) to remote sensors (or seismometers)
Implementation Method 4
Water injection generates increased reservoir pore pressure which causes an increase in shear stress in reservoir rocks
Implementation Method 5
changes in fluid pressures result in perturbation of the in-situ stresses
Implementation Method 6
The anisotropy is generally due to heterogeneity in reservoir rocks
Implementation Method 7
the pressure diffusion is a dominant mechanism of seismicity triggered by fluid injections
Data Source
AI summary
A system of and method for determining whether a liquid moving in an oil-bearing reservoir rock formation is water or oil is provided. The oil-bearing rock formation includes at production well(s) and source(s) of injected water during normal oil production. A fluid pathway is identified, baseline number of passive microseismic events is established, passive microseismic events in the fluid pathway are monitored during oil production to sense microseismic events, the sensed microseismic events are compared to a baseline number of passive microseismic events. The fluid causing the microseismic events is determined to be water if the sensed number of microseismic events approaches the baseline number of passive microseismic events per the predetermined unit, and if the baseline number of passive microseismic is measured during a time period when the water injection is greater than the rate of water injection during normal oil production.