Abstract: A method and apparatus for producing gas from a hydrate formation includes the use of at least one wellbore which penetrates the hydrate formation and further extends into an aquifer below the hydrate formation. The aquifer provides relatively warm water which may be produced up and into the hydrate formation thereby causing the release of gas from the hydrate. Suitable flow control and monitoring equipment may be included to control the flow of water produced from the aquifer and gas produced from the hydrate formation.

Abstract: A down hole tool and apparatus is described for logging and/or remedial operations in a wellbore in a hydrocarbon reservoir. The tool comprises an autonomous unit for measuring down hole conditions, preferably flow conditions. The autonomous unit comprises locomotion means for providing a motion along the wellbore; means for detecting the down hole conditions; and logic means for controlling the unit, the logic means being capable of making decisions based on at least two input parameters. It can be separably attached to a wireline unit connected to the surface or launched from the surface. The connection system between both units can be repeatedly operated under down hole conditions and preferably includes an active component for closing and/or breaking the connection.

Abstract: A down hole tool and apparatus is described for logging and/or remedial operations in a wellbore in a hydrocarbon reservoir. The tool comprises an autonomous unit for measuring down hole conditions, preferably flow conditions. The autonomous unit comprises locomotion means for providing a motion along the wellbore; means for detecting the down hole conditions; and logic means for controlling the unit, the logic means being capable of making decisions based on at least two input parameters. It can be separably attached to a wireline unit connected to the surface or launched from the surface. The connection system between both units can be repeatedly operated under down hole conditions and preferably includes an active component for closing and/or breaking the connection.

Abstract: A down hole tool and apparatus is described for logging and/or remedial operations in a wellbore in a hydrocarbon reservoir. The tool comprises an autonomous unit for measuring down hole conditions, preferably flow conditions. The autonomous unit comprises locomotion means for providing a motion along said wellbore; means for detecting said down hole conditions; and logic means for controlling said unit, said logic means being capable of making decisions based on at least two input parameters. It can be separably attached to a wireline unit connected to the surface or launched from the surface. The correction system between both units can be repeatedly operated under down hole conditions and preferably includes an active component for closing and/or breaking the connection.

Abstract: A downhole tool and apparatus is described for logging and/or remedial operations in a wellbore in a hydrocarbon reservoir. The tool comprises an autonomous unit (1) for measuring downhole conditions, preferably flow conditions. The autonomous unit comprises locomotion means (12) for providing a motion along said wellbore; means (14) for detecting said downhole conditions; and logic means (113) for controlling said unit, said logic means being capable of making decisions based on at least two input parameters. It can be separately attached to a wireline unit (22) connected to the surface or launched from the surface. The connection system (31, 32) between both units can be repeatedly operated under down hole conditions and preferably includes an active component for closing and/or breaking the connection.

Abstract: A method of warning of the onset of pipe sticking in a rotary drilling operation using a drill string comprising: (a) monitoring the pressure of a drilling fluid being pumped through the drill string during drilling over predetermined periods of time to obtain series of pressure measurements; (b) monitoring the torque required to rotate the drill string during said periods to obtain series of torque measurements; (c) obtaining the skew (third moment) of each series of pressure measurements according to the relationship ##EQU1## wherein N is the number of pressure measurements xi in the series, xmean is the average value of the measurements in the series, and .sigma. is the standard deviation of the measurements in the series; (d) obtaining the normalized standard deviation .sigma.n of the torque measurements in each corresponding series of torque measurements according to the relationship .sigma.n=(.sigma./ymean) wherein .sigma.

Abstract: A method of detecting a fluid influx in a well being drilled with a drill string having a drilling fluid circulated therethrough from a tank via a supply line system connected to the drill string, the method being used while connecting or disconnecting a pipe to or from the drill string and comprising the steps of:a) ceasing circulation of the drilling fluid;b) disconnecting the supply line system from the drill string so as to allow any drilling fluid in the system to flow back into the tank while connecting or disconnecting a pipe;c) reconnecting the supply line to the drill string and recommencing circulation of the fluid;d) while repeating a)-c) during the normal course of drilling the well, monitoring the change in level of fluid in the tank so as to determine a model of the change in level in the tank with respect to time during steps a)-c); ande) comparing the change in tank level observed when subsequently performing steps a)-c) with the change predicted by the model so as to detect a difference there

Abstract: A method of determining fluid influx or loss from a well being drilled from a floating vessel and using a drilling fluid, the method comprising monitoring the flow of fluid from the well to obtain a varying signal indicative of the variation in flow from the well, monitoring the heave motion of the vessel to obtain a varying signal indicative of said motion, using the signal indicative of the heave motion to calculate the expected variation in fluid flow from the well due to said motion, using said calculated flow to correct the varying flow signal to compensate for any flow component due to heave motion and monitoring the compensated signal for an indication of fluid influx or loss from the well.

Abstract: An arrangement for finding the direction of a sound in a medium has a thin shell structure having a circular symmetry. The structure can flex in response to incident sound energy from the medium to perturb the form of the structure. A membrane of a piezo-electric material with an anisotropic piezo-electric response to distortion is arranged to be distorted by the perturbation of the thin shell structure. The response of the membrane to this perturbation permits the direction of the incident sound to be indicated. The membrane can be of polyvinylidene difluoride with anisotropic properties. The membrane may be formed into a "dome" for example by fluid pressure inside a hemispherical shell closed by the membrane.

Abstract: An apparatus and method for detecting the direction of a sound. A thin shell structure is permitted to flex in response to incident sound and perturb the form of the shell. The perturbation is detected and from this the direction of the sound can be determined.