摘要:
Method for multi-parameter inversion using elastic inversion. This method decomposes data into offset/angle groups and performs inversion on them in sequential order. This method can significantly speed up convergence of the iterative inversion process, and is therefore most advantageous when used for full waveform inversion (FWI). The present inventive approach draws upon relationships between reflection energy and reflection angle, or equivalently, offset dependence in elastic FWI. The invention uses recognition that the amplitudes of small angle (near offset) reflections are largely determined by acoustic impedance alone (1), independent for the most part of Vp/Vs. Large angle (middle and far offset) reflections are affected by Ip, Vp/Vs (2) and other earth parameters such as density (3) and anisotropy. Therefore, the present inventive method decomposes data into angle or offset groups in performing multi-parameter FWI to reduce crosstalk between the different model parameters being determined in the inversion.
摘要:
A method is presented for partitioning a simulation model into a plurality of subdomains that may each be assigned to one of a plurality of processors. The method includes creating a representation of a topology graph of a simulation model in a tangible, computer readable medium. The topology graph includes a plurality of computational elements and a plurality of connections between those elements. Each of the plurality of connections is weighted to create a plurality of weights, and each of the plurality of weights is scaled. Optionally, the weights can be mapped to different interval of values. Based on the weights information the topology graph is partitioned into two or more subdomains, wherein a partition boundary follows a local topographical minimum in the topology graph. A subdomain is assigned to each of the plurality of processors.
摘要:
Method for estimating residual moveout in common image gathers (51) of seismic data for use in velocity tomography (57). The method iteratively (56) flattens (55) the common image gathers against a specified reference trace through the application of conjugate-gradient least-squares inversion (53). Different from other picking methods which need to identify and track strong amplitudes, the inventive method automatically inverts for the depth residual for every grid point in the image gather. There is no need to identify and track events.
摘要:
There is provided a device and method for high speed hydraulic actuation. The method includes adjusting a position of an actuator using a hydraulic pressure regulator. Adjusting the position of the actuator includes increasing pressure on the hydraulic pressure regulator to open the actuator using a first solenoid, or decreasing pressure on the hydraulic pressure regulator to close the actuator using a second solenoid.
摘要:
A method for hydraulically fracturing subterranean formations in a manner resulting in improved propping of fractures, particularly in ductile rock formations such as gas-containing shales having a high clay content. The method allows for improved hydrocarbon production. The method involves injecting a first fluid having a first proppant concentration into the subsurface formation to form a fracture, reducing the pressure in the fracture and allowing the fracture to substantially close, and injecting a second fluid having a second proppant concentration into the fracture to re-open the fracture. The second proppant concentration is greater than the first proppant concentration. A portion of the proppant is effectively retained in the reopened fracture.
摘要:
Exemplary embodiments of the present technology provide systems and methods for producing power from coalbed methane (CBM) with decreased CO2 emissions. For example, a method of producing power according to an exemplary embodiment includes converting a feedstock from a hydrocarbon source into a gas mixture comprising CO2 and H2. The gas mixture is injected into a coalbed to cause CBM to desorb from the coal and CO2 to adsorb onto the coal. The hydrocarbon source is separate from the coalbed, i.e., does not exchange hydrocarbons with the hydrocarbon source. A gas mixture is produced from the coalbed, wherein the produced gas mixture includes H2 and CH4. The gas mixture may be combusted to generate power, while releasing lower amounts of CO2 than would be released from the combustion of pure CH4.
摘要:
Systems and methods to inhibit packoff during drilling assembly removal from a wellbore, utilizing a drilling assembly that includes a transition region between a first section having a first cross-sectional area and a second section having a second cross-sectional area, wherein the second cross-sectional area is greater than the first cross-sectional area. The transition region includes a fluidizing assembly configured to partially fluidize a portion of the cuttings bed that is proximal to the transition region, and/or be in fluid communication with a flow control assembly configured to control flow rate of a fluidizing stream from the fluidizing assembly and to the portion of cuttings bed.
摘要:
Autonomous units and methods for downhole, multi-zone perforation and fracture stimulation for hydrocarbon production. The autonomous unit may be a perforating gun assembly, a bridge plug assembly, or fracturing plug assembly. The autonomous units are dimensioned and arranged to be deployed within a wellbore without an electric wireline. The autonomous units may be fabricated from a friable material so as to self-destruct upon receiving a signal. The autonomous units include a position locator for sensing the presence of objects along the wellbore and generating depth signals in response. The autonomous units also include an on-board controller for processing the depth signals and for activating an actuatable tool at a zone of interest.
摘要:
A method for stimulating a multi-zone wellbore completed with a string of production casing, including pumping a first volume of acidic fluid into the wellbore under pressure, and then injecting the first volume of acidic fluid into a first zone of interest along the production casing dropping at least one plug into the wellbore, the plug being fabricated from a material that substantially dissolves in the presence of the acidic fluid at or over a selected period of time.
摘要:
Method for estimating reflector dips in a window of post stack image traces (51) of seismic data for use in velocity tomography (57). The method iteratively (56) flattens (55) the image traces against a specified reference trace through the application of conjugate-gradient least-squares inversion (53). Different from other dip estimation methods which emphasize on strong-amplitude reflectors, the inventive method automatically inverts for the reflector dip for every grid point in the image window.