Wellbore Pressure Correction for Density Variations
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Solution Overview
Problem
Traditional pressure transient analysis in hydrocarbon well development is hindered by inaccuracies due to estimation of reservoir pressure from measurements taken away from the actual reservoir location, failing to account for fluid density variations across the wellbore depth, which is particularly problematic in highly permeable reservoirs where pressure changes are low and density variations significantly impact readings.
Innovation Solution
The method involves correcting transient pressure test data by accounting for fluid density variations between the gauge depth and mid-reservoir depth in the wellbore, using a series of nodes to estimate pressures at each depth interval, and determining a corrected mid-reservoir pressure profile within a specified tolerance value, thereby improving the accuracy of pressure transient analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pressure measurements are taken at gauge depth away from the reservoir location, then measurement simplicity is improved, but pressure measurement precision deteriorates due to fluid density variations across the wellbore depth
Solution Approach 1:
The patent divides the wellbore depth interval into multiple discrete depth levels or segments. By segmenting the continuous depth profile into discrete levels, the method can apply density corrections at each segment boundary, transforming a single imprecise measurement into a series of corrected measurements that collectively represent the reservoir pressure more accurately.
Solution Approach 2:
The patent introduces fluid density as an intermediary parameter to bridge the gap between gauge depth pressure measurements and reservoir location pressure. By using density variations as a mediator, the method translates pressure readings taken at one depth to equivalent pressures at the reservoir location, resolving the discrepancy between measurement simplicity and precision.
2Device complexity
If traditional pressure estimation methods are used, then analysis complexity is reduced, but reservoir parameter determination accuracy deteriorates in highly permeable reservoirs
Solution Approach 1:
The patent changes the approach from direct pressure estimation to a multi-parameter correction method that incorporates fluid density variations, depth intervals, and pressure gradient calculations. By transforming the simple estimation problem into a multi-parameter analysis, the method achieves higher accuracy in determining reservoir parameters for highly permeable reservoirs where pressure changes are subtle.
3Ease of operation
If density variations are not accounted for, then measurement process simplicity is maintained, but pressure profile accuracy deteriorates
Solution Approach 1:
The patent performs preliminary density calculations and corrections before finalizing the pressure profile determination. By pre-calculating density variations at different depth levels and applying these corrections in advance, the method maintains operational simplicity while achieving high pressure profile accuracy through proactive rather than reactive correction.
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 enhances the accuracy of reservoir development parameters, such as well operating pressure and flow rate, by providing a more precise pressure profile and derivative analysis, leading to more effective hydrocarbon well development and production optimization.
Implementation Method 1
correcting transient pressure test data to account for variations of fluid density between a gauge depth (GD) and a mid-reservoir depth (MRD) in a wellbore
Data Source
AI summary
Method and system for developing reservoirs, such as hydrocarbon reservoirs or aquifers, including correcting pressure transient test data to account for variations of fluid density between a gauge depth and a mid-reservoir depth in a wellbore. Gauge depth pressure and temperature measurements, and density correlations are used to estimate mid-reservoir depth pressures, which can be used in a pressure transient analysis.