Technologies for multiphase hydrate fraction modeling include devices and methods for receiving an initial feed composition of a constant volume cell and a time series of pressure data and temperature data for the cell during a test procedure. The devices and methods include determining a non-equilibrium hydrate fraction for the constant volume cell based on the time series of pressure data and temperature data, predicting one or more phase components of the constant volume cell based on the non-equilibrium hydrate fraction. The devices and methods may include displaying gas composition in the constant volume cell over the time series based on the prediction.

The present invention discloses methods and apparatus for dissociating hydrates obstructing a pipeline. Energy in the form of microwaves is supplied to the hydrate, wherein the frequency of the microwaves is varied within a predetermined range rather than a single fixed frequency. Thus, the optimum frequency, i.e., that which provides the greatest possible transfer of energy to the water, considering the temperature, pressure and type of hydrate in each particular application, is scanned and the effectiveness and efficiency of the operation is improved. The range preferably encompasses the largest possible number of statistically significant optimum frequencies considering the various operating ranges of the pipeline and various possible types of hydrates. In another aspect, an initial step is provided where an exploratory scan is performed to determine what the specific optimum frequency is for an application. Then the frequency of the microwaves is adjusted and fixed at the determined specific optimum frequency. Also disclosed is a microwave generating device for performing the frequency range scanning.

A method for undersea in-situ exploitation of natural gas hydrates is provided. The method includes: obtaining a well pattern layout diagram of a natural gas hydrate exploitation block based on a natural gas hydrate simulation exploitation model; carrying an undersea in-situ exploitation system to a target sea area using a ship configured to deploy deep-water equipment, selecting the well location according to the well pattern layout diagram; lowering a drilling device using a casing drilling technique; lowering a completion device, lowering a completion pipe string into the well, and connecting the completion device to an undersea wellhead to perform completion operation; and lowering the wellhead device, connecting the wellhead device to the completion pipe string, connecting the wellhead device to a production pipeline, and starting a depressurization exploitation process to reduce the pressure at a reservoir to make gas and water flow into the production pipeline to be extracted.

A well drilling device for undersea in-situ exploitation of a natural gas hydrate is provided. The well drilling device includes a well drilling module, wherein the well drilling module includes a frame, a portal framed lead rail and a manipulator are mounted in the frame, a lower hydraulic tong is mounted at the bottom of the frame, an upper hydraulic tong is arranged coaxially above the lower hydraulic tong, and a coaxial space between the upper hydraulic tong and the lower hydraulic tong is a drilling column placement position; the upper hydraulic tong is mounted in a top drive, and the top drive is assembled in the portal framed lead rail to move vertically in a vertical direction of the portal framed lead rail; and a pipe rack is arranged in a rotation range of the manipulator, and is configured to store and place a drilling column.

A process for removing an obstruction (13) caused by gas hydrates or water ice from the tubing (12) of a hydrocarbon production or injection well or a riser using a microwave. The process comprises passing a microwave generating and emitting tool (5) on wireline (8) down the tubing (12) and supplying electrical power to the tool via the wireline (8) or from a battery to produce microwave energy and direct it to the gas hydrate and/or water ice deposit (13), thereby melting deposit and unblocking the well.

A method for determining a safe density window of a hydrate formation considering a mud cake under an action of drilling fluids is provided. The method establishes a heat-fluid-solid-chemical multi-field coupling model considering the seepage effect of the mud cake at the well wall and the influence of natural gas hydrate decomposition. The simulation results show the distribution of pore pressure, temperature, and solute concentration in the drilling fluid around the well after the drilling fluid invades. Based on the determination of multi-field coupling model, the determination results, combined with a Cullen-Moore criterion, and manner for calculating a safe density window of a hydrate formation considering the mud cake under the action of the drilling fluid is further established.

A device for characterizing and testing on-site basic parameter of a natural gas hydrate includes a servo transmission mechanism, a pressure-resistant manipulator, a sealing mechanism, a data acquisition system, a resistivity testing system, an outlet metering system and an undisturbed permeability testing module; the undisturbed permeability testing module is used for testing a permeability of a hydrate sample subjected to sample transfer; the pressurizing system is used for adjusting a pressure of each point in the device; the servo transmission mechanism includes a pressure-resistant sample transfer manipulator and a servo driver; the servo driver is used for driving the pressure-resistant sample transfer manipulator to reciprocating motion, and the pressure-resistant sample transfer manipulator is used for separating the sample to be tested from the sheath under a pressure and pushing the sample into a holder; and the resistivity testing system is used for detecting a resistivity value.

A system for subsea operations and associated methods are disclosed. The system includes a well adapter to be associated with a production or monitoring well where the well adapter can receive a cap for capping the production or monitoring well and can receive a valve package to allow flow of production fluids therethrough, from the production well to the well adapter.

A device for characterizing and testing on-site basic parameter of a natural gas hydrate includes a servo transmission mechanism, a pressure-resistant manipulator, a sealing mechanism, a data acquisition system, a resistivity testing system, an outlet metering system and an undisturbed permeability testing module; the undisturbed permeability testing module is used for testing a permeability of a hydrate sample subjected to sample transfer; the pressurizing system is used for adjusting a pressure of each point in the device; the servo transmission mechanism includes a pressure-resistant sample transfer manipulator and a servo driver; the servo driver is used for driving the pressure-resistant sample transfer manipulator to reciprocating motion, and the pressure-resistant sample transfer manipulator is used for separating the sample to be tested from the sheath under a pressure and pushing the sample into a holder; and the resistivity testing system is used for detecting a resistivity value.

This disclosure relates to techniques for determining a dissociation constant of a reservoir that includes methane hydrate and generating a methane hydrate production output that may be used to inform certain decisions related to processing a reservoir that includes the methane hydrate. In some embodiments, the techniques may include determining the dissociation constant using multiple pressures measured at different flowrates at time points from within a wellbore.