Natural gas hydrate formation drilling simulation device

A natural gas hydrate drilling simulation device, comprising:

• a hydrate rock core simulation system;
• a drilling system;
• a drilling fluid injection system;
• and
• a drilling fluid treatment system,
• wherein the hydrate rock core simulation system comprises:
• a hydrate formation simulation wellbore;
• an artificial rock core filling in an inner cavity of the hydrate formation simulation wellbore;
• a water bath jacket wrapped on an outer side of the hydrate formation simulation wellbore;
• and
• a low temperature water bath connected with the water bath jacket for controlling the temperature of an internal environment of the hydrate formation simulation wellbore,
• wherein the drilling system comprises:
• a bracket having a base, an upright post, a wellbore fixing bracket, a rotary connector fixing bracket and a motor platform, the upright post being installed at one side of the base;
• a high pressure rotary connecting device of a hollow structure which is fixedly installed at an upper side of the hydrate formation simulation wellbore, the hollow structure communicating with the inner cavity of the hydrate formation simulation wellbore;
• a drilling device having a drill pipe stretching into the hollow structure of the high pressure rotary connecting device and extending to the inner cavity of the hydrate formation simulation wellbore;
• and
• a hydraulic device connected with the drill pipe for providing a downward pressure for the drill pipe,
• wherein one of the sides of the wellbore fixing bracket, the rotary connector fixing bracket and the motor platform is fixedly connected to the upright post, and the other sides of the wellbore fixing bracket, the rotary connector fixing bracket and the motor platform are fixedly connected with the hydrate formation simulation wellbore, the high pressure rotary connecting device and the drilling device respectively,
• wherein the drilling fluid injection system comprises:
• a mud tank;
• a mud cooling device arranged in the mud tank;
• a stirring device arranged in the mud tank;
• a first mud pump;
• a second mud pump, with inlet pipelines of the first mud pump and the second mud pump being connected with the mud tank;
• a heater, with an outlet pipeline of the first mud pump being connected with an inlet pipeline of the heater, an outlet pipeline of the second mud pump being jointed with an outlet pipeline of the heater through a tee joint, a temperature sensor being arranged at an outlet of the tee joint for measuring the mud temperature, and mixed mud being divided by the tee joint into two paths after being connected;
• a drilling fluid flowmeter;
• and
• an overflow valve, wherein one path of the two paths for the mixed mud divided by the tee joint is connected with a mud inlet by the drilling fluid flowmeter through a pipeline, and the other path of the two paths for the mixed mud divided by the tee joint is connected with the mud tank through the overflow valve,
• wherein the drilling fluid treatment system comprises:
• a high pressure sand remover having an inlet and an outlet, the inlet being connected with a mud outlet formed on the high pressure rotary connecting device through a pipeline;
• a back pressure and overflow control system;
• a gas-liquid separator, with the outlet of the high pressure sand remover being connected with the gas-liquid separator through the back pressure and overflow control system;
• a liquid flowmeter, with liquid flowing out from the gas-liquid separator returning to the mud tank through the liquid flowmeter;
• and
• a gas flowmeter metering a gas flowing out from the gas-liquid separator.