Formation Testing Assembly with Downhole Pump and Mud Circulation
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Solution Overview
Problem
Conventional well drilling apparatuses do not facilitate transient pressure formation testing or formation testing involving a draw-down phase, which are essential for evaluating subterranean formations effectively.
Innovation Solution
A formation testing assembly that includes a hydraulic bladder or packer to seal the well annulus, a downhole pump to extract formation fluid, and a method involving the circulation of drilling mud to mix with the formation fluid, allowing for the monitoring of pressure perturbations and build-up phases, thereby determining reservoir parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional drilling apparatus are used, then basic drilling operations can be performed, but transient pressure formation testing and draw-down phase testing cannot be conducted
Solution Approach 1:
The drilling apparatus is divided into functionally independent modules: a drill string for drilling operations, a separate formation testing assembly with packers for isolation, a downhole pump for fluid extraction, and a circulation system. This segmentation allows each module to perform its specific function optimally while maintaining overall system versatility for both drilling and transient pressure formation testing.
Solution Approach 2:
The drill string serves multiple functions: it acts as both the drilling tool and the circulation pathway for drilling fluid. The circulation system can operate in different modes (drilling circulation, formation testing circulation, well control circulation), making the apparatus universally applicable to multiple operations without requiring completely separate equipment.
2Measurement precision
If formation fluid is pumped from the formation, then pressure perturbations can be monitored for reservoir evaluation, but well control issues may arise
Solution Approach 1:
The system continuously monitors pressure at multiple points (formation pressure, annulus pressure, drill string pressure) and uses this feedback to automatically adjust the pumping rate and circulation parameters. This closed-loop control ensures that pressure perturbations remain within safe limits, maintaining well control stability while achieving precise reservoir parameter measurements.
Solution Approach 2:
Drilling mud serves as an intermediary fluid that transmits pressure information from the formation to surface measurement equipment. The mud circulation system acts as a mediator between the formation testing operations and well control requirements, allowing pressure data to be obtained while maintaining well stability through controlled fluid circulation.
3Adaptability or versatility
If drilling mud is circulated to mix with formation fluid, then gas proportion can be controlled, but additional circulation equipment is required
Solution Approach 1:
The drilling mud circulation system is designed to perform multiple functions: it cools and lubricates the drill bit during drilling, carries cuttings to the surface, serves as the medium for formation fluid mixing during testing, and provides well control. This multi-functionality eliminates the need for separate circulation equipment, achieving gas control capability without proportionally increasing device complexity.
Solution Approach 2:
The circulation system uses the drilling mud itself to accomplish multiple tasks simultaneously. The same fluid that cools the drill bit also mixes with formation fluid to control gas proportion, and the same circulation pathway transports both drilling cuttings and formation samples to the surface. This self-service approach maximizes the utility of existing equipment.
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
Enables accurate formation testing in open hole environments, alleviates well control issues, and provides detailed reservoir parameter analysis, including formation pressure and fluid mobility.
Implementation Method 1
a hydraulic bladder or packer to seal the well annulus
Implementation Method 2
a downhole pump to extract formation fluid
Implementation Method 3
the circulation of drilling mud to mix with the formation fluid
Data Source
AI summary
Formation testing which may involve circulating mud in a pipe string from a mud pit through a port in the pipe string to a downhole diverter sub, wherein the pipe string is suspended in a wellbore extending into a subterranean formation, operating a downhole pump to pump formation fluid from the formation, wherein the formation fluid comprises gas, and mixing the pumped formation fluid with circulated mud such that a proportion of the pumped formation gas in the circulated mud is maintained below a threshold value.