Reservoir Fluid Mapping via Mud-Gas and 4D Seismic Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies face challenges in accurately identifying remaining oil targets within mature hydrocarbon reservoirs, particularly due to limitations in 4D seismic resolution and interpretation uncertainties, leading to reduced oil production and increased costs.
Innovation Solution
A method that combines 4D seismic data with mud-gas data to generate a refined model of the hydrocarbon field, improving reservoir fluid mapping resolution and accuracy, allowing for more precise identification of oil targets and reduced gas production risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If 4D seismic data is used to map reservoir fluids, then a qualitative indication of fluid changes can be obtained, but quantitative reservoir fluid properties data cannot be provided and interpretation uncertainties remain
Solution Approach 1:
The patent combines 4D seismic data with mud-gas logging data to create a hybrid approach that overcomes the limitations of each individual method. The seismic data provides broad spatial coverage and temporal changes, while mud-gas data provides quantitative fluid properties, together delivering both qualitative and quantitative information with reduced interpretation uncertainties.
Solution Approach 2:
Mud-gas logging acts as an intermediary that bridges the gap between seismic data and direct fluid measurement. The mud-gas data provides transfer functions that convert seismic amplitude changes into quantitative fluid properties, enabling the seismic data to yield quantitative information without requiring direct fluid sampling.
2Measurement precision
If 4D seismic data is used for fluid mapping, then changes in pressure, density and saturation can be detected, but practical vertical resolution is limited to about 20-30 meters
Solution Approach 1:
The patent merges 4D seismic data with mud-gas logging data to overcome the vertical resolution limitation. While seismic data provides broad detection capability, the mud-gas logging provides high-resolution vertical fluid property measurements along the wellbore, together achieving both wide coverage and fine vertical detail.
Solution Approach 2:
The patent adds the vertical dimension of high-resolution measurement through mud-gas logging along the wellbore trajectory. This complements the seismic data's horizontal and temporal dimensions, creating a multi-dimensional view of reservoir fluids that overcomes the vertical resolution bottleneck of seismic alone.
3Measurement precision
If density-neutron separation data from petrophysical logs is used to distinguish oil and gas, then fluid identification can be achieved, but uncertainties remain due to lithology and reservoir fluid effects
Solution Approach 1:
Mud-gas logging serves as an intermediary that provides direct fluid composition information independent of lithology effects. The mud-gas data measures actual gas present in the reservoir fluid, bypassing the indirect inference required by density-neutron logs and eliminating lithology-related interpretation uncertainties.
Solution Approach 2:
The patent uses mud-gas logging data to validate and refine the interpretation of petrophysical logs. The direct fluid measurements from mud-gas logging provide feedback that confirms or corrects fluid identification from density-neutron separation, improving overall reliability.
4Measurement precision
If sampling while drilling, downhole fluid sampling, or downhole fluid analyser techniques are used, then direct fluid analysis can be obtained, but these techniques are not well suited to horizontal production wells due to well length and orientation
Solution Approach 1:
The patent extracts the fluid analysis capability to the surface through mud-gas logging. Instead of requiring downhole equipment in horizontal wells, the system extracts gas from the drilling mud at the surface for analysis, eliminating the operational difficulties of downhole sampling in long horizontal wells while maintaining direct fluid analysis capability.
Solution Approach 2:
The patent replaces the mechanical downhole sampling and analysis system with a surface-based mud-gas logging system. This substitution eliminates the need for complex downhole equipment in horizontal wells while achieving the same fluid analysis objective through a different mechanical approach.
5Reliability
If a conservative approach is taken to avoid gas breakthrough, then risk of large gas production is minimized, but oil production and profitability are reduced
Solution Approach 1:
The patent implements continuous feedback through mud-gas logging during drilling and completion operations. This real-time monitoring provides feedback on fluid contacts and gas presence, enabling dynamic adjustment of drilling and completion parameters to optimize oil production while actively managing gas breakthrough risk, rather than relying on static conservative assumptions.
Solution Approach 2:
The patent performs preliminary fluid characterization through mud-gas logging before finalizing well completion design. This preliminary action provides advance knowledge of fluid distribution and gas contacts, enabling optimized completion strategies that maximize oil production from the first foot of the well while pre-planning mitigation for potential gas breakthrough.
Data Source
AI summary
A method of mapping reservoir fluid in a mature field includes identifying a region of interest within a hydrocarbon field, drilling a plurality of production wells through the region of interest, and collecting mud gas data as each production well is drilled. This mud gas data is used to generate a reservoir fluid property log, such as gas-oil ratio log, along a length of each of the production wells, which is in turn used to generate a refined model based on the 4D seismic data. The refined model permits better reservoir fluid mapping and has an improved vertical resolution at the region of interest than the first model of the field.