Natural Gas Hydrate Drilling Simulation Device
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Solution Overview
Problem
Current drilling simulation technologies lack the capability to accurately measure phase changes and characteristics of natural gas hydrates in real-time under high pressure and low temperature conditions, essential for simulating the complex NGH drilling process, due to harsh formation conditions and complex experimental media.
Innovation Solution
A natural gas hydrate drilling simulation device comprising a hydrate rock core simulation system, drilling system, drilling fluid injection system, and drilling fluid treatment system, which includes a hydrate formation simulation wellbore, high pressure rotary connecting device, hydraulic device, and detection systems for real-time temperature, pressure, and stress measurements, allowing for controlled simulation of drilling parameters and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional oil and gas drilling technology is adopted for NGH drilling, then drilling efficiency may be improved, but safety accidents such as blowout and borehole collapse may occur due to inability to control bottom hole heat and pressure
Solution Approach 1:
The patent applies parameter changes by controlling bottom hole temperature, pressure, and drilling fluid properties to prevent NGH decomposition. The system adjusts these parameters in real-time to maintain stable drilling conditions, resolving the contradiction between drilling efficiency and safety by enabling effective NGH drilling through precise parameter management.
2Productivity
If drilling speed is increased to improve productivity, then NGH decomposition is accelerated due to heat generation, leading to borehole diameter expansion and blowout
Solution Approach 1:
The patent implements feedback control by continuously monitoring bottom hole temperature, pressure, and drilling parameters, then adjusting drilling speed and fluid properties accordingly. This closed-loop control prevents NGH decomposition and borehole instability while maintaining optimal drilling speed, resolving the contradiction between productivity and harmful thermal effects.
Solution Approach 2:
The system dynamically adjusts drilling parameters including speed, weight on bit, and drilling fluid properties based on real-time bottom hole conditions. By changing these parameters adaptively, the system prevents excessive heat generation and NGH decomposition while maintaining high drilling efficiency.
3Productivity
If drilling pressure is increased to improve drilling speed, then formation breakdown occurs resulting in drilling fluid leakage
Solution Approach 1:
The patent adjusts drilling pressure and drilling fluid properties dynamically based on formation strength characteristics. By optimizing these parameters within safe limits and using real-time monitoring, the system achieves high drilling speed without exceeding formation rupture pressure, preventing drilling fluid leakage.
4Object-generated harmful factors
If NGH decomposition is allowed to occur, then gas circulates with drilling fluid reducing hydrostatic pressure, but this accelerates further decomposition causing vicious circle and severe accidents
Solution Approach 1:
The patent applies preliminary anti-action by preventing NGH decomposition before it can cause harmful gas circulation and pressure reduction. Through controlled bottom hole temperature and pressure management, the system stops the decomposition process at its source, eliminating the vicious circle mechanism and maintaining bottom hole stability.
Solution Approach 2:
The system uses real-time monitoring of bottom hole conditions to detect early signs of NGH decomposition and immediately adjusts drilling parameters to counteract the process. This feedback control prevents gas circulation and hydrostatic pressure reduction, maintaining system stability.
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 real-time measurement and control of temperature and pressure changes during the drilling process, simulating various hydrate rock core conditions and drilling fluid parameters, thereby optimizing drilling conditions and evaluating drilling risks effectively.
Implementation Method 1
the water bath jacket is wrapped on the outer side of the hydrate formation simulation wellbore, and the low temperature water bath is connected with the water bath jacket for controlling the temperature of the internal environment of the hydrate formation simulation wellbore
Implementation Method 2
a heater, a second mud pump, a drilling fluid flowmeter and an overflow valve. The inlet pipelines of the first mud pump and the second mud pump are connected with the mud tank, the outlet pipeline of the first mud pump is connected with the heater
Implementation Method 3
The mud tank is provided with the mud cooling device and the stirring device
Implementation Method 4
formation stress near the well wall and the bottom hole is released, which will decompose NGH to produce a gas and decomposed water
Data Source
AI summary
A natural gas hydrate drilling simulation device, includes a hydrate rock core simulation system, a drilling system, a drilling fluid injection system and a drilling fluid treatment system. The hydrate rock core simulation system includes a hydrate formation simulation wellbore, an artificial rock core, a water bath jacket and low temperature water bath. The drilling system includes a bracket, a high pressure rotary connecting device, a hydraulic device and a drilling device. The drilling fluid injection system includes a mud tank, a drilling fluid flowmeter, mud pumps and an overflow valve. The drilling fluid treatment system includes a high pressure sand remover, a back pressure and overflow control system, a gas-liquid separator, a dyer, a gas flowmeter, a liquid flowmeter and a mud treatment tank. This natural gas hydrate drilling simulation device performs simulation experiments under a variety of downhole working condition environments.