Real-Time Coal-Bed Gas Parameter Inversion During Drilling
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Solution Overview
Problem
Current methods for testing coal-bed gas parameters during drilling are limited by few test points, lack of real-time data, long test durations, complex processes, and inability to accurately reflect coal-bed gas and outburst risk distributions, especially in long or deep boreholes.
Innovation Solution
A method and device for real-time testing and inversion calculation of coal-bed gas parameters during drilling, involving a blowout prevention device, gas parameter monitor, and drainage system to measure gas flow and concentration, calculate gas pressure and content, and predict outburst risk without disrupting drilling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed-point sampling measurement method is used to test coal-bed gas content, then measurement accuracy is improved, but sampling complexity and duration increase significantly
Solution Approach 1:
The patent replaces the mechanical sampling system (drilling, sampling, laboratory analysis) with a gas flow detection system that measures coal-bed gas content through gas discharge characteristics during drilling, eliminating complex mechanical sampling operations while maintaining measurement accuracy
Solution Approach 2:
The patent uses pneumatic principles to measure coal-bed gas content by detecting gas flow rate, pressure, and concentration during drilling operations, replacing the need for physical coal sampling and laboratory analysis
2Productivity
If drilling-based cutting removal method is used for fast test, then test speed is improved, but sampling point-fixing performance and accuracy deteriorate
Solution Approach 1:
The patent implements real-time feedback by continuously monitoring gas flow rate, pressure, and concentration during drilling, allowing immediate detection and recording of gas parameters at each drilling depth, ensuring both speed and accuracy through continuous data acquisition
Solution Approach 2:
The patent maintains continuous gas parameter measurement throughout the drilling process without interruption, ensuring that gas content data is collected continuously at all depths while drilling progresses, eliminating the need for separate sampling operations
3Measurement precision
If hole sealing balance test method is used to obtain coal-bed gas pressure, then measurement accuracy is improved, but test duration and complexity increase
Solution Approach 1:
The patent performs gas pressure measurement preliminarily during the drilling process itself, using the drilling operation to naturally expose and measure gas parameters before any separate testing is required, eliminating the need for additional hole sealing and balance test operations
Solution Approach 2:
The patent merges gas pressure measurement with the drilling operation by detecting gas flow and pressure characteristics during normal drilling, combining two separate processes (drilling and gas testing) into one simultaneous operation
4Ease of operation
If drilling indicators are tested after drill withdrawal, then test simplicity is improved, but number of test points and reflection accuracy decrease
Solution Approach 1:
The patent maintains continuous gas parameter measurement throughout the entire drilling process, collecting data at every depth interval as drilling progresses, ensuring comprehensive coverage of gas distribution without omitting any locations
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, fast, and real-time testing of coal-bed gas parameters and outburst risk along the entire borehole length, reducing test complexity and duration, and improving reflection of actual gas and risk distributions without requiring special devices or occupying drilling time.
Implementation Method 1
testing a gas flow and a gas concentration of an orifice in real time while-drilling
Implementation Method 2
testing a gas flow and a gas concentration of an orifice in real time while-drilling
Implementation Method 3
calculating a real-time drilling gas discharge amount and an average drilling gas discharge amount of the orifice
Implementation Method 4
inversely calculating a coal-bed gas pressure at a drill bit based on borehole and coal-bed permeability parameters
Implementation Method 5
calculating a coal-bed gas content according to a gas content and gas pressure relational expression
Data Source
AI summary
The present invention provides an inversion calculation method of coal-bed gas parameters of fast test while-drilling. The technical solution is that an inversion calculation method of coal-bed gas parameters of fast test while-drilling includes: during drilling in a coal bed, testing a gas flow and a gas concentration of an orifice in real time while-drilling, calculating drilling gas discharge amounts of the orifice, inversely calculating a coal-bed gas pressure at a drill bit based on borehole and coal-bed permeability parameters, and calculating a coal-bed gas content according to a gas content and gas pressure relational expression. The present invention has the beneficial effects that the present invention does not occupy the drilling and drill rod replacement time, is accurate, convenient, real-time and fast, and can test and calculate the coal-bed gas parameters of each section along the whole borehole length.