Schlumberger Technology Corporation

Anadrill, Inc.

Stuart I Jardine

Michael Paul Barrett

Michael Charles Sheppard

Joseph Ayoub

Terizhandur S Ramakrishnan

Peter Fitzgerald

Marc Lesage

Dominic P McCann

Timothy Tristam Jervis

David B White

Dominic McCann

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.

Method for exploitation of gas hydrates

A method is given of fracturing a subterranean formation including the step of a) pumping at least one device actively transmitting data that provide information on the device position, and further comprising the step of assessing the fracture geometry based on the positions of said at least one device, or b) pumping metallic elements, preferably as proppant agents, and further locating the position of said metallic elements with a tool selected from the group consisting of magnetometers, resistivity tools, electromagnetic devices and ultra-long arrays of electrodes, and further comprising the step of assessing the fracture geometry based on the positions of said metallic elements. The method allows monitoring of the fracture geometry and proppant placement.

Means and method for assessing the geometry of a subterranean fracture during or after a hydraulic fracturing treatment

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.

Down hole tool and method

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 ( ) for measuring downhole conditions, preferably flow conditions. The autonomous unit comprises locomotion means ( ) for providing a motion along said wellbore; means ( ) for detecting said downhole 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 separately 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.

Downhole tool and method

This invention describes methods and apparatus for identifying potentially hazardous events during the drilling or production of hydrocarbon reservoirs where such events include kick detection in a well, fluid influx from a drilled formation, sticking pipe in a borehole, pipe washouts or formation fracture generation, according to measurements made by instruments such as flowmeter paddles, electro-chemical transducers or MWD parameter sensors. Measured signals are compared to a number of possible signals and the probability for said measured signals representing such an event are determined.

Alarm system for wellbore site

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. is the standard deviation of the measurements in the series and ymean is the average value of the measurements in the series; and (e) comparing skew and .sigma.n for the series so as to identify corresponding changes in both and raising an alarm when the magnitude of said changes pass predetermined alarm values.

Method of warning of pipe sticking during drilling operations

The invention is related to a method of determininng the instantaneous rotation speed of a drill string or a drill bit in a borehole or the lateral shocks applied to the string or bit. The centripetal acceleration of the drill string is measured at at least two opposite ends of a drill string diameter so as to obtain two centripetal acceleration signals ac1 and ac2; the signals ac1 and ac2 are combined and the instantaneous rotation speed or the lateral shocks are derived from said combined signal. The accelerometers must be of the type delivering a signal with a DC component. An important application of the invention is to transform drill string rotation speed dependent data acquired versus time with a constant sampling time increment T.sub.c separating successive data, into compensated data which would be obtained for a substantially constant drill string rotation speed S.sub.c. The compensated data are obtained either by adjusting the constant sampling time interval T.sub.c into a variable sampling time increment T.sub.v, using the measured instantaneous rotation speed S, or by selecting the data which have been acquired during periods of time during which the instantaneous rotation speed of the drill string varied within predetermined limits only.

Method and apparatus for determining characteristics of the movement of

A method is provided for determining the state of wear of a multicone drill bit. Vibrations generated by the working drill bit are detected and converted into a time oscillatory signal from which a frequency spectrum is derived. The periodicity of the frequency spectrum is extracted. The rate of rotation of at least one cone is determined from the periodicity and the state of wear of the drill bit is derived from the rate of cone rotation. The oscillatory signal represents the variation in amplitude of the vertical or torsional force applied to the drill bit. To extract periodicity, a set of harmonics in the frequency spectrum is given prominence by computing the cepstrum of the frequency spectrum or by obtaining an harmonic-enhanced spectrum. The fundamental frequency in the set of harmonics is determined and the rate of cone rotation is derived from the fundamental frequency.

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Cambridge, United Kingdom

Stuart I Jardine