Wellbore Mapping for Refracturing Using Packer Pair Isolation
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Solution Overview
Problem
Conventional refracturing methods lack the ability to accurately identify clusters with proper zonal isolation and cross communication, leading to increased risks and costs associated with restimulating interconnected clusters.
Innovation Solution
A two-step approach utilizing a packer pair with pressure and temperature sensors to map the wellbore, allowing for hydraulic setting and unsetting of packers to isolate zones and determine pressure integrity, thereby creating a roadmap for refracturing treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional refracturing methods are used without mapping, then treatment can proceed quickly, but the risk of cross communication and loss of pressure integrity increases
Solution Approach 1:
The system performs a preliminary mapping operation before refracturing by running a tool with sensors and packers through the wellbore to identify clusters with proper zonal isolation. This preliminary assessment creates a roadmap that guides subsequent refracturing operations, allowing operators to target only isolated clusters while avoiding cross-communicating ones, thus maintaining pressure integrity without sacrificing operational efficiency
Solution Approach 2:
The mapping tool acts as an intermediary between the refracturing design phase and execution phase. It includes packers to isolate zones, sensors to detect pressure changes, and a communication system to transmit data to the surface. This intermediary system provides critical information about zonal isolation status, enabling informed decisions about which clusters to treat while maintaining overall well integrity
2Measurement precision
If mapping with packer pair and sensors is performed, then identification of isolated clusters improves, but device complexity increases
Solution Approach 1:
The mapping tool is designed as a multi-functional device that combines several capabilities in one assembly: hydraulic packers for zonal isolation, pressure sensors for detecting pressure changes, temperature sensors for additional characterization, and communication systems for data transmission. This universal tool can assess multiple clusters throughout the wellbore in a single run, providing comprehensive mapping data without requiring multiple separate operations or simpler individual components
Solution Approach 2:
The system uses hydraulic packers that can be set and unset remotely to isolate specific zones during the mapping operation. The hydraulic setting mechanism allows the packers to seal against the wellbore wall, creating isolated zones for pressure testing. This hydraulic approach provides reliable zonal isolation without requiring complex mechanical setting mechanisms, reducing overall device complexity while maintaining measurement precision
3Quantity of substance
If refracturing is performed without identifying cross communication, then treatment costs are lower initially, but additional costs arise from treating non-isolated clusters
Solution Approach 1:
The mapping system provides feedback about the isolation status of each cluster by measuring pressure changes during the mapping operation. When a cluster is properly isolated, pressure changes are contained within that zone; when cross-communication exists, pressure changes are detected in adjacent zones. This feedback information is transmitted to the surface and used to create a roadmap that guides refracturing decisions, ensuring treatment materials are injected only into isolated clusters where they will be effective
Solution Approach 2:
The system performs preliminary identification of isolated versus non-isolated clusters before refracturing begins. By mapping the wellbore in advance and creating a detailed roadmap of zonal isolation status, operators can plan refracturing treatments to target only suitable clusters. This preliminary action prevents waste of treatment materials on non-isolated clusters and avoids the additional costs that would arise from ineffective treatments
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 method reduces treatment costs by identifying clusters with proper zonal isolation and reducing the risk of cross communication, enabling targeted refracturing and extending well productivity.
Implementation Method 1
straddle packers are set mechanically or based on a pressure differential between an inner diameter of the tool and an annulus
Implementation Method 2
Hydraulic injection is a method performed by pumping fluid into a formation at a pressure sufficient to create fractures in the formation
Implementation Method 3
first sensors positioned between the packer pair, downstream sensors positioned downstream from the downstream packer, upstream sensors positioned upstream from the upstream packer
Data Source
AI summary
Examples of the present disclosure relate to systems and methods for mapping a wellbore for refracturing. More specifically, embodiments are directed towards utilizing downhole pressure data to identify previously untreated clusters, clusters with cross contamination, and clusters with proper zonal isolation with full pressure integrity.