Abstract:
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.
Abstract translation:一种用于产生地下特征的图像的方法,包括提供包含关于所述特征的信息的地震数据,所述地震数据包括i)包括第一上行波场和第一下行波场的第一数据集,ii)第二 数据集,其包括第二上行波场和第二下行波场,其中所述第二数据集在比所述第一数据集晚的时间以时间间隔被收集,从而创建一个前进的4D差分数据集U 通过从另一个中减去第一和第二前进波场中的一个并通过从另一个减去第一和第二下行波场中的一个来创建下行4D差分数据集D.创建加权函数W 这是差分数据集的相似度的函数,并且通过生成4D相似性堆栈来创建特征的图像,其中4D相似性堆栈被定义为(U + D)* W / 2。
Abstract:
A distributed fiber optic acoustic sensing system comprises an elongate body having an outer surface, an optical fiber disposed on the outer surface at a first predetermined wrap angle, and light transmitting and receiving means optically connected to the fiber for. The elongate body may include at least one substantially flat face, and/or a layer of swellable elastomer surrounding the body, and/or an outer elastomeric tube surrounding the elastomer layer. There may be at least one sensor pad disposed in the outer layer, the sensor pad comprising a stiffener and at least one longitudinal fiber affixed thereto or embedded therein. There may be a body of protective material surrounding the tube, which may have an outer surface that includes at least one substantially flat face and at least one sensor pad disposed in the body.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract translation:一种用于产生地下特征的图像的方法,包括提供包含关于所述特征的信息的地震数据,所述地震数据包括i)包括第一上行波场和第一下行波场的第一数据集,ii)第二 数据集,其包括第二上行波场和第二下行波场,其中所述第二数据集在比所述第一数据集晚的时间以时间间隔被收集,从而创建一个前进的4D差分数据集U 通过从另一个中减去第一和第二前进波场中的一个并通过从另一个减去第一和第二下行波场中的一个来创建下行4D差分数据集D.创建加权函数W 这是差分数据集的相似度的函数,并且通过生成4D相似性堆栈来创建特征的图像,其中4D相似性堆栈被定义为(U + D)* W / 2。
Abstract:
A distributed fiber optic acoustic sensing system comprises an elongate body having an outer surface, an optical fiber disposed on the outer surface at a first predetermined wrap angle, and light transmitting and receiving means optically connected to the fiber for. The elongate body may include at least one substantially flat face, and/or a layer of swellable elastomer surrounding the body, and/or an outer elastomeric tube surrounding the elastomer layer. There may be at least one sensor pad disposed in the outer layer, the sensor pad comprising a stiffener and at least one longitudinal fiber affixed thereto or embedded therein. There may be a body of protective material surrounding the tube, which may have an outer surface that includes at least one substantially flat face and at least one sensor pad disposed in the body.