Shell Oil Comapny

Johan Cornelis Hornman

Albena Alexandrova Mateeva

Boris Nikolaevich Kuvshinov

Jorge Louis Lopez

Johannis Josephus Den Boer

Jeremiah Glen Pearce

Jeffery Joseph Mestayer

William Birch

Jorge Luis Lopez

Steven James Maas

Peter Berkeley Wills

Paul James Hatchell

Guido Jozef Maria Baeten

Paul Maarten Zwartjes

Grant Slack Irwin

A distributed fiber optic cable including an elongate body and optical fibers longitudinally housed in the elongate body. The optical fibers lie in in sinusoidal paths along longitudinal surfaces of a prism. The distributed fiber optic cable can be used for sensing an acoustic wave by measuring backscattered light from a laser pulse input into the optical fibers in the fiber optic cable.

Cable comprising sinusoidal paths along longitudinal surfaces for use in distributed sensing

A seismic receiver array has a plurality of seismic receiver channels, each coupled to a local surrounding in an earth formation. A formation-material-dependent response of each seismic receiver channel is determined, and associated with an assumed depth for the corresponding seismic receiver channel. The formation-material-dependent responses as function of the assumed depth are compared to an independent depth log of at least one petrophysical parameter of the earth formation as a function of depth along the borehole. Based on the comparison, a set of lags between said assumed depth and depth in the independent depth log is determined, that provides the best correlation between the formation-material-dependent response and the independent depth log of the at least one petrophysical parameter of the earth formation. The assumed depth of each seismic receiver channel can thus be aligned with corresponding depths in the independent depth log.

Method of calibrating depths of a seismic receiver array

A first stationary seismic receiver array is provided in a first non-vertically directed first borehole section of a first array of non-vertically directed first borehole sections, and a second stationary seismic receiver array is provided in a second non-vertically directed first borehole section of the first array of non-vertically directed first borehole sections. A seismic source assembly is moved axially through a first non-vertically directed second borehole section from at least a first position to a second position of a plurality of first borehole positions along a length of the first non-vertically directed second borehole section. The seismic source assembly contains a repeatable seismic source, which is activated when the seismic source assembly is in the first position and when the seismic source assembly is in the second position. First and second shots of seismic signals are recorded with at least each of the first and second stationary seismic receivers.

Method and system for recording seismic signals

A method may include providing a sensor in a first wellbore segment, providing a sensor in a second wellbore segment, observing upgoing acoustic waves or downgoing acoustic waves with the sensors, and separating the upgoing acoustic waves and/or the downgoing acoustic waves from a total wavefield. The first wellbore segment and the second wellbore segment may be separated by a distance. At least one of the wellbore segments may be non-vertical and/or the first wellbore segment may not be parallel to the second wellbore segment. The first wellbore segment may be part of a first set of wellbores and the second wellbore segment may be part of a second set of wellbores. The separated upgoing and downgoing acoustic waves may be used to generate deghosted data.

Method and system for acquisition of seismic data

A distributed fiber optic acoustic sensing system includes a cable having a cable length. The cable has an elongated body having an outer surface, and at least one straight optical fiber extending parallel to a longitudinal axis of the cable along the cable length; and one or more non-straight optical fibers, such as two orthogonal sinusoidal optical fibers extending along the cable length, or a helically wrapped optical fiber extending along the cable length. The sensing system further has light transmitting and receiving means optically connected to the optical fibers.

Detecting broadside acoustic signals with a fiber optical distributed acoustic sensing (DAS) assembly

A distributed fiber optic cable comprises an elongate body and a first optical fiber longitudinally housed in the body, wherein the fiber describes a sinusoid having an amplitude and a first wavelength along the length of the body and wherein the sinusoid rotates along the length of the body so as to describe a twisted sinusoid having a twist wavelength. A method for sensing an acoustic wave comprises a) providing a set of signals collected from the cable, b) processing the signals so as to divide the fiber in each twist wavelength of cable into a predetermined number of channels, c) measuring the amplitudes in each channel and calculating the maximum and minimum amplitude in a preselected length of cable, d) using the calculated maximum and minimum for the preselected length of cable to determine the amplitude and direction of the wave at the preselected length of cable.

Cable comprising twisted sinusoid for use in distributed sensing

A method of distributed acoustic sensing includes providing a fiber optic distributed acoustic sensing system having a cable. A straight optical fiber extends parallel to a longitudinal axis of the cable along the cable length. A helically wrapped optical fiber extends along the cable length. The method includes transmitting optical signals into and receiving backscattered signals out of the optical fibers consisting of a component of said optical signals which component has been backscattered from impurities or inhomogeneities in the optical fibers, observing changes in the backscattered signals caused by axial stretching and compressing of the optical fibers caused by an incident wave, comparing the backscattered signals of the straight optical fiber and the helically wrapped fiber, and determining, based on the comparing of the backscattered signals, a direction of wave propagation of the incident wave with respect to the fiber axis for detecting broadside waves and axial waves distinguishably.

A system and method for handling seismic cable having sensor stations thereon is provided. The seismic cable is positionable about the seismic field for measuring seismic parameters of a subsurface structure. The system includes a mobile unit, a reel and a winch assembly. The mobile unit is positionable about the seismic field, and has a platform. The reel is supportable on the platform with the seismic cable disposable about the reel. The winch assembly is carried by the mobile unit and includes a plurality of cable guides. At least one of the cable guides has a passageway with an adjustable dimension for aligning and guiding the seismic cable and the sensor stations passing therethrough.

Seismic cable handling system and method

A method for generating an image of a subsurface feature, comprises providing seismic data containing information about the feature, comprising i) a first dataset comprising a first up-going wave-field and a first down-going wave-field, ii) a second dataset comprising a second up-going wave-field and a second down-going wave-field, wherein the second dataset is collected at a time that is later than the first dataset by a time interval, creating an up-going 4D difference dataset U by subtracting one of the first and second up-going wave-fields from the other and creating a down-going 4D difference dataset D by subtracting one of the first and second down-going wave-fields from the other, creating a weighting function W that is a function of the similarity of the difference datasets, and creating an image of the feature by generating a 4D similarity stack, where the 4D similarity stack is defined as (U+D)*W/2.

Growing community of inventors

Rijswijk, Netherlands

Johan Cornelis Hornman