Microseismic Fault Plane Determination via Common Nodal Plane Grouping
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Solution Overview
Problem
Current seismic monitoring methods cannot distinguish between the two possible fault planes represented by the nodal planes of a microseismic event's moment tensor, limiting the accuracy of fault plane determination in passive seismic analysis.
Innovation Solution
The method involves grouping microseismic events in close proximity to identify a common nodal plane across multiple events, determining the moment tensor for each event using inversion algorithms, and analyzing these tensors to pinpoint the actual fault plane by identifying the plane common to all events within the group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moment tensor inversion is used to determine fault planes, then the mathematical representation of seismic forces is obtained, but two indistinguishable nodal planes are produced making it impossible to identify the actual fault plane
Solution Approach 1:
The patent combines multiple independent microseismic events that occurred on the same fault plane into a single analysis group. By merging the moment tensors of multiple events, the method identifies common nodal planes across all events, allowing differentiation between the actual fault plane and the spurious nodal plane. This collective approach transforms an ambiguous single-event problem into a solvable multi-event system.
Solution Approach 2:
The method employs an iterative feedback process where initial moment tensor inversions provide nodal plane candidates, which are then used to group related events. The grouping results feed back into refined moment tensor analysis, progressively improving the identification of common fault planes. This feedback loop continues until stable fault plane identification is achieved.
2Productivity
If single microseismic events are analyzed in isolation, then individual moment tensors can be calculated, but the fault plane cannot be uniquely identified due to the ambiguity of nodal planes
Solution Approach 1:
The patent merges multiple microseismic events into groups based on their spatial proximity and temporal relationships. By analyzing events in groups rather than individually, the method maintains processing efficiency while achieving accurate fault plane identification through the common nodal plane approach.
Solution Approach 2:
The patent segments the overall seismic dataset into multiple groups of related microseismic events. Each group is analyzed separately to identify its common fault plane, allowing parallel processing of multiple groups while maintaining high measurement precision for each segment.
3Loss of information
If traditional seismic monitoring is used, then general subsurface information can be obtained, but detailed fault plane characteristics and fracture progression cannot be accurately determined
Solution Approach 1:
The patent combines fault plane determination with fracture progression monitoring by analyzing sequences of microseismic events along the same fault plane. By merging the analysis of multiple events occurring during hydraulic fracturing operations, the method provides detailed information about both the fault plane geometry and the progression of fractures over time.
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 approach allows for precise determination of the fault plane, enhancing the accuracy of seismic data processing and improving the understanding of subsurface formations and hydraulic fracturing processes.
Implementation Method 1
seismic energy signal that propagates through the earth
Implementation Method 2
Propagating seismic energy is partially reflected, refracted, diffracted
Implementation Method 3
Propagating seismic energy is partially reflected, refracted, diffracted
Implementation Method 4
determining the moment tensor for each event using inversion algorithms
Data Source
Figure 1~2
Figure 3
Figure 4A~4G
AI summary
The present disclosure includes a method of passive seismic data processing comprising determining a moment tensor for each of a plurality of microseismic events using an inversion algorithm and raw data detected at a plurality of receivers, each of the moment tensors including two nodal planes and grouping a subset of the plurality of microseismic events into a family of microseismic events. The method also includes determining whether the family of microseismic events include a single plane that is common across each of the nodal planes of the microseismic events for the moment tensors of the family of microseismic events. The method additionally includes selecting a solution fault plane for the family of microseismic events, the solution fault plane being the single plane. The present disclosure may also include associated systems and apparatuses.