Reservoir Grid Correction via 4D Seismic Skeleton Flow Analysis
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Solution Overview
Problem
Current reservoir grid models for hydrocarbon recovery face challenges in achieving accurate geological property values, especially between wells, due to limited and indirect measurements, leading to unsatisfactory accuracy and the need for improved methods to evaluate and correct these values.
Innovation Solution
A method utilizing 4D seismic images to analyze and correct reservoir grid models by calculating a skeleton representing fluid flow paths and associating geological property values, allowing for the evaluation of flow time values and iterative correction of property values to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wells are drilled to measure geological properties using logging techniques or core sampling, then measurement accuracy is improved, but the cost and complexity of drilling numerous wells increases significantly
Solution Approach 1:
The patent introduces an intermediary substance (fluid such as water or gas) injected into the reservoir to indirectly measure geological properties. Instead of directly sampling rock formations through multiple wells, the fluid acts as a mediator that interacts with the formation, and its flow behavior (pressure, temperature, composition changes) provides information about permeability, porosity, and other properties, thereby reducing the need for extensive well drilling while maintaining measurement accuracy
Solution Approach 2:
The patent replaces the mechanical drilling and physical sampling system with a fluid injection and measurement system. Instead of mechanically extracting core samples through drilled wells, the system uses fluid dynamics (Darcy flow, pressure propagation) to indirectly characterize the reservoir, substituting mechanical intrusion with hydraulic measurement
2Device complexity
If seismic measurements are used to estimate geological properties between wells, then the need for additional wells is reduced, but the resolution and accuracy of the measurements deteriorate due to low vertical resolution (few tens of meters)
Solution Approach 1:
The patent merges two measurement approaches: well-based direct measurements (logging, pressure data) and seismic measurements. By combining these complementary data sources, the system leverages the high vertical resolution of well data and the spatial coverage of seismic data, creating a hybrid model that achieves both reduced drilling complexity and improved measurement accuracy throughout the reservoir volume
Solution Approach 2:
The patent transforms seismic data from its native low-resolution form into enhanced geological property estimates by using fluid injection responses as additional constraints. The injection-induced pressure and flow data provide new parameters that, when integrated with seismic data, resolve the vertical resolution limitation and improve overall measurement precision
3Measurement precision
If Assisted History Matching is performed to adjust the reservoir grid by comparing well measurements with simulation predictions, then the accuracy of predicted values is improved, but the time and computational resources required increase
Solution Approach 1:
The patent performs preliminary characterization of the reservoir using fluid injection tests before full-scale production simulation. By conducting injection experiments early in the development process and using the observed flow responses to pre-calibrate geological properties (permeability, porosity, heterogeneity), the system establishes an initially accurate reservoir model that requires less iterative adjustment during history matching, thereby reducing overall computational time and resource requirements
Data Source
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AI summary
Computer implemented method (50) for analyzing a reservoir grid modeling a reservoir geological formation, said reservoir grid corresponding to a 3D grid of cells associated to respective values of at least one geological property, comprising: - (S51) obtaining a 4D seismic image of the reservoir geological formation; - (S52) calculating a skeleton (20) of the 4D seismic image, said skeleton extending between at least one origin (10) and a plurality of extremities (21a-21h); - (S53) associating each point of the skeleton to a value of the at least one geological property of the reservoir grid; - (S54) calculating flow time values for a fluid flowing from the origin to the extremities along the skeleton, based on the at least one geological property values associated to the points of the skeleton; - (S51) analyzing the reservoir grid based on the flow time values.