The present invention is a method of generating a model of a random field which has directionally varying continuity. First, a tentative model for the random field is specified. Second, connected strings of nodes within the model are identified. Third, a spectral simulation on each of the strings of nodes is performed to determine updated values for the random field. Finally, the tentative model is updated with the data values from the spectral simulations.
Method For Determining Formation Properties From Seismic Attributes
A method of geophysical prospecting using seismic trace attribute analysis for formation characterization. More particularly, a method for selection of seismic traces which most accurately represent the subsurface formation in the area of a seismic survey is disclosed. In one embodiment, inflection-point interval analysis is used to account for effects of local surfaces.
Process For Constructing Three-Dimensional Geologic Models Having Adjustable Geologic Interfaces
Application
#6480790 Nov 12, 2002
Filed
Oct 11, 2000
Inventor
Craig S. Calvert (Houston, TX) ·
Thomas A. Jones (Bellaire, TX)
Appl. No.
09/686300
Assignee
ExxonMobil Upstream Research Company (Houston, TX)
International Classification
G01V 128
U.S. Classification
702 14, 702 16
Abstract
A process for constructing a three-dimensional geologic model of a subsurface earth volume in which the positions of geologic interfaces within the model are adjusted as the model is being constructed. The resulting geologic model should be consistent with all available geologic and geophysical information regarding the subsurface earth volume, including information regarding the spatial attributes of geologic interfaces within said subsurface earth volume.
Claim
We claim: 1. A process for constructing a three-dimensional geologic model of a subsurface earth volume containing one or more geologic interfaces, said process comprising the steps of: (a) generating a tentative geologic model of said subsurface earth volume, said tentative geologic model comprising a three-dimensional array of contiguous model blocks, each model block having tentative values for one or more rock properties assigned thereto, said tentative geologic model containing tentative positions for said one or more geologic interfaces; (b) specifying training criteria which define the spatial attributes of geologic interfaces and the characteristics of rock properties in said subsurface earth volume; (c) calculating statistics that describe the spatial attributes of said tentative geologic-interface positions and the characteristics of said tentative rock-property values in said tentative geologic model; and (d) comparing statistics calculated in step (c) with corresponding training criteria specified in step (b) and either (1) if said statistics do not match said training criteria within specified limits, perturbing the tentative position within said tentative geologic model of at least a portion of at least one of said geologic interfaces, updating said tentative geologic model, and repeating steps (c) and (d), or (2) if said statistics match said training criteria within said specified limits, accepting said tentative geologic model as the three-dimensional geologic model for said subsurface earth volume. 2. The process of claim 1, wherein each geologic interface in said subsurface earth volume is represented in said tentative geologic model by a set of interface nodes, and wherein said perturbation in step (d)(1) comprises changing the position of only one of said interface nodes. 3. The process of claim 1, wherein each geologic interface in said subsurface earth volume is represented in said tentative geologic model by a set of interface nodes, and wherein said perturbation in step (d)(1) comprises changing the positions of all interface nodes within a specified distance from a specific interface node. 4.
Seismic Attribute Analysis Using Inflection Point Intervals
A method of geophysical prospecting using seismic trace attribute analysis for formation characterization. More particularly, a method for selection of seismic traces which most accurately represent the subsurface formation in the area of a seismic survey is disclosed. In one embodiment, inflection-point interval analysis is used to account for effects of local surfaces.
Method For Constructing 3-D Geologic Models By Combining Multiple Frequency Passbands
A process for constructing a three-dimensional geologic model of a subsurface earth volume wherein resolution scales of multiple diverse data types, including seismic data, are accounted for by generating multiple frequency passband models and combining them together to form the complete geologic model. Preferably, a model is generated for each of a low-frequency passband, a mid-frequency passband, and a high-frequency passband. When integrating seismic data into the modeling process, the seismic-frequency passband constitutes the mid-frequency passband model. The process further contemplates updating tentative frequency-passband models through optimization of assigned rock property values in each tentative model according to specified geological criteria. Such optimization is carried out by perturbation of the rock property values in a manner wherein the frequency content of each model is maintained.
Method For Constructing 3-D Geologic Models By Combining Multiple Frequency Passbands
A process for constructing a three-dimensional geologic model of a subsurface earth volume wherein resolution scales of multiple diverse data types, including seismic data, are accounted for by generating multiple frequency passband models and combining them together to form the complete geologic model. Preferably, a model is generated for each of a low-frequency passband, a mid-frequency passband, and a high-frequency passband. When integrating seismic data into the modeling process, the seismic-frequency passband constitutes the mid-frequency passband model. The process further contemplates updating tentative frequency-passband models through optimization of assigned rock property values in each tentative model according to specified geological criteria. Such optimization is carried out by perturbation of the rock property values in a manner wherein the frequency content of each model is maintained.
Method For Locally Controlling Spatial Continuity In Geologic Models
The present invention is a method of generating a geologic model which incorporates a local spatial trend in rock property continuity. Initially, a candidate geologic model is generated by assigning a rock-property value to each block of a model grid. Next, local spectra which characterize the desired local spatial trend in rock property continuity are specified. These local spectra are used to frequency scale the rock-property values of the candidate geologic model. The scaled rock-property values are then combined to generate a scaled geologic model that incorporates the local spatial trend in rock property continuity.
A method of forming a geologic model of a subsurface region is disclosed. Data related to the subsurface region is obtained. A framework is constructed to represent the subsurface region. A template is selected from a plurality of templates. The selected template provides at least one property that is characteristic of the subsurface region. The selected template is inserted into the framework, to form the geologic model. The geologic model is then outputted.
A method of forming a geologic model of a subsurface region is disclosed. Data related to the subsurface region is obtained. A framework is constructed to represent the subsurface region. A template is selected from a plurality of templates. The selected template provides at least one property that is characteristic of the subsurface region. The selected template is inserted into the framework, to form the geologic model. The geologic model is then outputted.
