Self-Drilling Formation Test Probe With Vibratory Drill-In Tubing
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Solution Overview
Problem
Conventional formation testing methods, such as drill stem testing (DST) and mini-DST, face challenges with wellbore contamination and sub-optimal formation contact, leading to inefficiencies and increased costs due to the need for large-scale equipment and significant fluid disposal, as well as logistical and environmental concerns.
Innovation Solution
A self-drilling probe system that extends and seats on the wellbore surface, equipped with a drill-in tubing and an exciter to induce vibrations, allowing it to bore through mud cake and invasion zones, thereby establishing an unobstructed conduit for fluid flow and reducing contamination, and includes flow control components for fluid sampling and pressure testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional drill stem testing (DST) is used, then formation properties can be determined, but large-scale equipment is required and significant fluid disposal is needed
Solution Approach 1:
The conventional DST system is segmented into a smaller, modular probe assembly that can be deployed via wireline. The probe is divided into functional components (drilling section, sampling chamber, filtering system) that can be integrated in a compact configuration, eliminating the need for large-scale DST equipment while maintaining formation testing capability.
Solution Approach 2:
The essential formation testing function is extracted from the complex DST system and concentrated into a small probe assembly. The probe contains only the necessary components for drilling, sampling, and filtering, removing unnecessary equipment and reducing overall system complexity while preserving the core measurement capability.
2Measurement precision
If conventional formation test probes are used, then fluid sampling can be performed, but wellbore contamination and sub-optimal formation contact occur
Solution Approach 1:
The probe performs preliminary drilling action before sampling to remove the mud cake layer and invasion zone. By pre-drilling a clean pathway into the formation, the probe eliminates the contaminated interface between wellbore and formation, ensuring that subsequent fluid sampling occurs from uncontaminated formation zones only.
Solution Approach 2:
The drilling mechanism acts as an intermediary between the wellbore and formation. It creates a clean transition zone by removing contaminated materials (mud cake, invasion zone) before the sampling chamber makes contact with formation fluids, thereby mediating the interface to prevent contamination.
3Productivity
If mini-DST equipment is used, then smaller scale testing is possible, but equipment and operational costs remain significant
Solution Approach 1:
The probe extracts only the necessary formation fluids for testing through its small sampling chamber and filtering system. This selective extraction capability allows minimal fluid withdrawal compared to mini-DST, reducing the volume of fluids that require disposal while maintaining adequate sample collection for accurate formation property determination.
Solution Approach 2:
The probe is designed as a disposable, single-use tool that is deployed via wireline, performs its function, and is then retrieved or abandoned. This eliminates the need for expensive, reusable mini-DST equipment and associated fluid disposal infrastructure, reducing overall operational costs despite the probe's temporary nature.
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
The self-drilling probe system enables efficient and contamination-reduced formation testing by penetrating mud cake and invasion zones, facilitating accurate fluid sampling and pressure testing while minimizing equipment and operational costs, thus improving the accuracy and efficiency of formation property determination.
Implementation Method 1
an exciter disposed within the body in contact with the drill-in tubing and operably configured to induce vibration in the drill-in tubing
Data Source
AI summary
A formation test probe and a formation test system and method for implementing a self-drilling probe are disclosed. In some embodiments, a test probe includes a body having a channel therethrough to a frontside port, and further includes drill-in tubing disposed within the channel and having a front tip that is extensible from the frontside port. An exciter is disposed within the body in contact with the drill-in tubing and operably configured to induce resonant vibration in the drill-in tubing during a drill-in phase of a formation test cycle.