Segmented Well Liners for On-Demand EM Waterfront Imaging
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Solution Overview
Problem
Existing deep electromagnetic (EM) surveys for monitoring waterflood fronts in hydrocarbon wells face challenges due to the thickness and cost of dedicated transmitters and receivers, metal casing attenuation, and high upfront costs of permanent electrode arrays, leading to inefficiencies and downtime in field operations.
Innovation Solution
Implementing segmentally insulated well liners with non-conductive spacers to create on-demand electromagnetic source and receiver electrodes, using production logging tools for temporary conversion, and performing forward and inverse modeling to monitor waterfront movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated EM transmitters and receivers are used for EM surveys, then measurement precision is improved, but device complexity and installation difficulty increase due to thicker and longer tool dimensions
Solution Approach 1:
The well liner is divided into multiple electrically isolated segments using non-conductive spacers. Each segment can function as an independent electrode, allowing the system to achieve EM survey capabilities using existing well liner components rather than requiring complex dedicated EM tools.
Solution Approach 2:
The well liner segments serve multiple functions: they provide structural support for the well, act as electromagnetic electrodes for surveying, and can be configured as either source or receiver electrodes. This multi-functionality eliminates the need for separate dedicated EM survey equipment.
2Productivity
If permanent electrode arrays are installed downhole for continuous monitoring, then productivity is improved through continuous data acquisition, but upfront cost and installation complexity increase significantly
Solution Approach 1:
The existing well liner structure serves as the electrode array without requiring separate installation of permanent electrodes. The well liner segments, already in place for well integrity, are repurposed as electromagnetic electrodes through the addition of non-conductive spacers, eliminating the need for expensive permanent electrode installation.
Solution Approach 2:
Instead of installing new permanent electrodes, the system recovers and repurposes the existing well liner segments as electromagnetic electrodes. The non-conductive spacers are added to create electrical isolation between segments, transforming the existing structure into a functional electrode array without additional major costs.
3Strength
If metal casings are used in wells, then structural integrity is improved, but EM sensitivity is greatly attenuated
Solution Approach 1:
The continuous metal casing is segmented into separate electrically isolated sections using non-conductive spacers. This segmentation allows EM fields to propagate between segments without being blocked by the continuous metal barrier, enabling EM surveys while maintaining the structural integrity provided by the metal well liner.
Solution Approach 2:
Non-conductive spacers are introduced as intermediary elements between metal well liner segments. These spacers act as electrical insulators that break the continuous metal path, allowing EM fields to pass through the well liner structure while the metal segments maintain their structural function.
4Measurement precision
If conventional EM surveys are performed on existing wells, then measurement precision is improved, but loss of time increases due to multi-day to week-long data acquisition
Solution Approach 1:
The well liner is pre-configured with non-conductive spacers and electrically isolated segments during well completion, so that the electrode array is ready for immediate use. This preliminary preparation eliminates the need for time-consuming electrode installation during subsequent EM surveys, reducing survey downtime.
Solution Approach 2:
The well liner segments serve as permanent electromagnetic electrodes that remain in place continuously, allowing EM surveys to be performed repeatedly without reinstalling equipment. This continuous configuration enables rapid sequential surveys, reducing the total time loss associated with multiple survey operations.
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 enables cost-effective, continuous, and efficient monitoring of waterfront movement with reduced downtime, allowing for optimized reservoir management and hydrocarbon production.
Implementation Method 1
electromagnetically performing a waterfront survey by conveying into a well at least one production logging tool that temporarily converts the plurality of well liners into at least one on-demand electromagnetic source electrode and at least one on-demand receiver electrode
Data Source
AI summary
A method for monitoring waterfront movement in a subsurface formation involves performing forward modeling of at least one deep electromagnetic survey of the waterfront movement, and determining locations for installing an electrically insulating spacer between well liners to form an on-demand electromagnetic source electrode. Based on the forward modeling, repeat survey time intervals are predicted. The method involves, during well completion, installing the electrically insulating spacer between the well liners in a reservoir to form at least one on-demand electromagnetic source electrode, and installing the electrically insulating spacer between the plurality of well liners in a reservoir to form an on-demand electromagnetic receiver electrode. A waterfront survey is performed by conveying a production logging tool into a well that temporarily converts the well liners into an on-demand electromagnetic source electrode and an on-demand receiver electrode, and inverse modeling of the waterfront survey is performed to produce a water saturation image.