Downhole Cleaning Efficiency Prediction via Shear Stress Segmentation
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Solution Overview
Problem
Existing methods for wellbore fluids displacement are imprecise due to their reliance on surface conditions independent of downhole conditions and the gelled fluid's history, leading to inefficient removal of residual oils and solids, which can hinder completion operations and damage the wellbore.
Innovation Solution
A method and system that predict the mechanical removal of gelled fluids by considering the gelled fluid's history at distinct wellbore depths and local downhole conditions, using an information handling system to determine the required shear stress profile and modify the displacement operation for effective cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface conditions are used to evaluate gelled fluid properties, then the evaluation process is simple and quick, but the accuracy of cleaning efficiency prediction is poor due to independence from downhole conditions
Solution Approach 1:
The wellbore is divided into multiple depth intervals, and the gelled fluid properties are evaluated separately at each interval. The three-dimensional flow profile is segmented into multiple annular segments, allowing independent analysis of shear stress and gel strength at different depths. This segmentation enables accurate prediction of cleaning efficiency at each location while managing computational complexity through systematic division of the problem.
Solution Approach 2:
The patent applies local quality by evaluating gelled fluid properties and flow conditions specific to each depth interval and annular segment. Instead of using uniform surface conditions, the model incorporates downhole temperature, pressure, and fluid properties at each location. The required shear stress profile is calculated locally based on actual downhole gel strength and flow conditions, providing accurate cleaning efficiency predictions tailored to each specific location in the wellbore.
2Reliability
If higher flow rates are used to create adequate shear on wellbore walls, then mechanical cleaning of gelled fluids is improved, but energy consumption and operational complexity increase
Solution Approach 1:
The patent applies dynamics by calculating the required shear stress profile that varies with depth and time during the displacement operation. The model dynamically adjusts the evaluation of cleaning efficiency based on the actual flow conditions, gel strength, and wellbore geometry at each depth interval. This dynamic approach allows optimization of flow rates to achieve adequate shear for effective cleaning while minimizing excessive energy consumption by avoiding uniformly high flow rates throughout the entire wellbore.
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 provides improved accuracy in assessing and enhancing the cleaning efficiency of wellbore fluids displacement operations, ensuring thorough removal of residual substances and minimizing operational burdens and wellbore damage.
Implementation Method 1
By circulating a fluid through the wellbore at a sufficient flow rate to create adequate shear on the wellbore walls, gelled fluids may be removed by erosion
Implementation Method 2
gelled fluids may be removed by erosion
Data Source
AI summary
Predicting the efficiency of downhole mechanical removal of one or more accreted materials from one or more wellbore walls may prevent the unnecessary consumption of resources in a wellbore fluids displacement operation. A method and system for removing accreted materials in a wellbore is provided, wherein the efficiency of mechanical removal of accreted materials may be characterized based, at least in part, on a comparison between one or more actual shear stresses exerted by a wellbore servicing fluid at one or more depths of the wellbore and one or more required shear stresses to remove the accreted materials from the depth. The one or more required shear stresses may be determined using one or more of one or more known properties of the one or more accreted materials, one or more rheology models, one or more hydraulic parameters, one or more wellbore hydraulic models, and one or more downhole conditions. To account for one or more effects of eccentricity in the wellbore, the one or more actual shear stresses exerted by wellbore servicing fluid may be determined by partitioning one or more three dimensional flow profiles into divided annular segments for individual analysis. To improve operational decision making, operators or automated processes may modify the wellbore fluids displacement operation based, at least in part, on the comparison. The comparison between the one or more actual shear stresses and the one or more required shear stresses may be used to generate a parameter that characterizes the cleaning efficiency of the wellbore fluids displacement operation.