Iterative Productivity Index Estimation for Multilateral Well Modeling
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Solution Overview
Problem
Existing multilateral well modeling and performance prediction techniques are inefficient and inaccurate, failing to properly capture the interplay between branches or laterals and the competition effects of inflow performance and interface effects of commingled production.
Innovation Solution
A method and system for determining the productivity of multilateral completions by iteratively modifying productivity indices for each lateral until modeled flowrates and commingled flowrates match well test data, accounting for the interplay between laterals and allowing for adjustments in wellhead pressure and inline control valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If existing analytic models are used to calculate the sum of productivity of individual branches, then the calculation is simple and rapid, but the accuracy is poor and does not capture the interplay between branches
Solution Approach 1:
The patent introduces an intermediary iterative process that acts as a mediator between the simple analytic model and the complex numeric model. The method uses analytic equations as a starting point and iteratively adjusts productivity indices based on numeric model feedback, creating an intermediate solution that achieves both speed and accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the numeric model's detailed simulation results are used to adjust and refine the analytic model's productivity indices. The iterative process continuously compares predicted versus actual performance and modifies the analytic model parameters accordingly, allowing the simpler model to learn from the more complex one.
2Measurement precision
If existing numeric models with detailed simulation are used, then the accuracy of capturing interplay between branches is improved, but the efficiency and speed are reduced
Solution Approach 1:
The patent segments the modeling process into two distinct parts: an analytic model for rapid calculation and a numeric model for detailed accuracy. By dividing the problem into these segments, the method can use the appropriate model for each aspect - the analytic model for overall trends and the numeric model for specific interplay effects.
Solution Approach 2:
Instead of always using the full numeric simulation, the patent applies partial action by using the numeric model only for the specific purpose of adjusting productivity indices in the analytic model. This excessive action of running numeric simulations selectively rather than continuously achieves high accuracy without the constant computational burden.
3Device complexity
If existing approaches are used, then the model complexity is low, but the ability to evaluate competition effects and interface effects of commingled production is insufficient
Solution Approach 1:
The patent changes the parameters of the analytic model by introducing adjustable productivity indices that are refined through iteration. These parameter changes allow the simple analytic structure to incorporate the complex effects of competition and interface interactions without increasing the fundamental model complexity.
Data Source
AI summary
A process for determining the productivity index of a multilateral completion using data from individual laterals and data from commingled well tests is disclosed. The process includes 1) determining the productivity index for each single lateral by iteratively altering the productivity index until the individual lateral flowrate based on a known reservoir pressure is matched and 2) further determining the productivity index by iteratively altering the productivity index until the commingled flowrate is matched. The productivity index may be used to set wellhead pressures and inline control valve (ICV) settings for production.