Dual-Piston Pump Control for Downhole Formation Testing
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Solution Overview
Problem
Current formation testing tools face challenges such as equipment failure, suboptimal performance due to multiple moving parts, and operational difficulties in high-pressure, high-temperature environments, which complicate the measurement of formation properties during drilling processes.
Innovation Solution
A downhole formation testing system with an improved fluid pump and control method, featuring a dual-piston design powered by a turbine-driven alternator, and a sophisticated control system that adjusts pump operation based on real-time formation parameters and environmental conditions to optimize sampling and fluid analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireline tools are used for formation testing, then measurement capability is improved, but operational time and cost increase due to tripping the drill string
Solution Approach 1:
The patent replaces the mechanical wireline tool system that requires tripping the drill string with a downhole formation testing system integrated into the drilling operation. The system uses a probe that can be positioned against the borehole wall during drilling, eliminating the need for separate wireline trips while maintaining formation testing capability through direct hydraulic coupling between the probe and formation
Solution Approach 2:
The system performs formation testing as a preliminary action during the drilling process itself, before the well is completed. The probe is positioned and formation properties are measured while the drill string is still in place, allowing measurements to be taken in advance of when they would traditionally be obtained via wireline tools
2Ease of operation
If traditional pumps are used in formation testing tools, then fluid sampling capability is improved, but reliability decreases due to multiple moving parts in harsh environments
Solution Approach 1:
The patent extracts and eliminates the traditional pump mechanism from the formation testing tool. Instead of using a pump to draw formation fluid into the borehole, the system relies on the natural pressure differential between the formation and the borehole, allowing fluid to flow into the borehole passively without mechanical pumping components
Solution Approach 2:
The system uses the natural pressure differential between the formation and borehole to drive fluid flow, making the system self-service without requiring external pumping power. The formation pressure itself provides the driving force for fluid sampling, eliminating the need for mechanical pumps and associated moving parts
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 efficient and reliable formation fluid sampling and analysis during drilling without the need to trip the drill string, reducing operational time and improving data accuracy under varying drilling conditions.
Implementation Method 1
The pump may be powered by a generator in the drill string that is driven by the mud flow down the drill string
Implementation Method 2
Drilling fluid, or 'mud,' is typically pumped down through the drill string to the drill bit. The drilling fluid lubricates and cools the drill bit, and it carries drill cuttings back to the surface in the annulus between the drill string and the borehole wall
Data Source
AI summary
A while-drilling tool comprising a motor, a transmission coupled to the motor, and a pump comprising a first piston disposed in a first chamber and a second piston disposed in a second chamber and coupled to the first piston. A planetary roller-screw is coupled between the pump and the transmission. A valve block is configured to fluidly communicate with the first and second pump chambers, a borehole in which the while-drilling tool is configured to be positioned, and a formation penetrated by the borehole.