Continuous PVT Phase Envelope Log Generation During Drilling
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Solution Overview
Problem
Existing methods for characterizing underground formations and obtaining PVT phase envelope logs are often time-consuming and discontinuous, providing limited real-time information during borehole drilling.
Innovation Solution
A method and system for continuously generating PVT phase envelope logs while drilling a borehole, utilizing surface mud logging equipment and downhole instruments to acquire chemical composition, pressure, and temperature data, and processing this information in real-time to create a continuous log of PVT properties along the well trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional discontinuous methods are used to obtain PVT phase envelope logs, then measurement precision may be maintained, but productivity is reduced due to time-consuming processes
Solution Approach 1:
The patent implements continuous measurement of PVT properties by integrating sensors that continuously sample formation fluid composition, pressure, and temperature during drilling operations. This continuous data acquisition eliminates the discontinuous nature of traditional methods, enabling real-time generation of phase envelope logs without interruption or significant time delay.
Solution Approach 2:
The system performs preliminary analysis of formation fluid composition using downhole spectroscopic sensors and surface analytical equipment before complete drilling operations are finished. This preliminary PVT characterization allows operators to make real-time decisions about drilling parameters and equipment design adjustments without waiting for post-drilling analysis.
2Loss of information
If continuous real-time measurement is implemented, then productivity and information availability are improved, but device complexity increases
Solution Approach 1:
The measurement system is divided into distinct functional modules: downhole spectroscopic sensors for composition analysis, downhole pressure and temperature sensors, surface analytical equipment for verification, and a processing system for integrating data and generating phase envelopes. This segmentation allows each component to be optimized independently and simplifies the overall system architecture.
Solution Approach 2:
The downhole tool assembly is designed to perform multiple functions: drilling operations, real-time fluid composition analysis via spectroscopy, pressure and temperature measurement, and data transmission to surface equipment. This multi-functionality reduces the need for separate specialized equipment and simplifies the overall measurement system.
3Measurement precision
If traditional batch processing methods are used, then device complexity is minimized, but measurement precision and real-time capability are reduced
Solution Approach 1:
The system implements real-time feedback loops where measured PVT properties are continuously compared against target values and drilling parameters are automatically adjusted. The phase envelope calculations provide feedback on fluid phase behavior that informs real-time decisions about drilling conditions, completion design, and production optimization.
Solution Approach 2:
Traditional mechanical batch processing methods are replaced with automated computational systems that continuously calculate phase envelopes from real-time sensor data. Software algorithms automatically integrate composition, pressure, and temperature measurements to generate updated phase envelopes, eliminating the need for manual data processing and batch analysis.
Data Source
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AI summary
A method for generating a phase envelope log to characterize a subsurface formation includes drilling the borehole with a drill string, circulating a drilling fluid in the borehole, drawing a fluid sample representing a fluid contained in the subsurface formation, estimating a PVT parameter indicative of an in-situ condition of the subsurface formation from the drawn fluid sample, determining at least two phase envelopes at different depths using the estimated PVT parameter, and creating a phase envelope log formed of a continuous series of phase envelopes using the phase envelopes. A related system includes a drill string, a fluid sampling system, and a processor that estimates a PVT parameter indicative of an in-situ condition of the subsurface formation, determines at least two phase envelopes at different depths using the PVT parameter, and creates the phase envelope log.