Integrated reservoir characterization using optimal non-parametric transformations and structure preserving inversion /
This dissertation presents effective and novel techniques for
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739892071&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | This dissertation presents effective and novel techniques for the correlation of petrophysical data, the integration of 3-D seismic data with well data, and the integration of multiphase production history into a statically derived reservoir model. First, an optimal non-parametric transformation method is proposed for correlation of petrophysical data, such as permeability estimates from well logs. This new approach overcomes the limitation of conventional linear or multiple linear regression method which requires a functional relationship between dependent and independent variables to be presumed. The non-parametric transformation approach does not require a priori assumptions of functional forms and the optimal transformations are derived solely based on the data set using an iterative procedure called alternating conditional expectations (ACE). The application of the optimal transformations to the field data shows much improved permeability estimation from porosity and from well logs as compared to the conventional regression approach. Second, a two-stage approach to integrating 3-D seismic data into reservoir characterization is presented. The method combines non-parametric transformations with geostatistical algorithms. First, attributes extracted from 3-D seismic data are calibrated with reservoir properties derived from well data using optimal non-parametric transformations to obtain the maximal correlation between two data sets. Then cokriging or stochastic indicator cosimulation is carried out in the transformed space to generate conditional realizations of reservoir properties. The advantages of using this two-stage approach are: 1) it allows for the non-linear relationship between reservoir properties and seismic attributes and exploits the seismic attributes to their fullest potential, and 2) cokriging or cosimulation is considerably simplified when carried in conjunction with the optimal transformations because of a significant reduction in the variance function calculations, particularly when multiple seismic attributes are involved. The proposed approach has been successfully applied to a synthetic case and a field 3-D seismic data integration case. Finally, a novel approach called structure preserving inversion is developed for integrating multiphase production data to further improve the reservoir models derived from static data. Unlike the traditional full perturbation inverse method, the proposed inversion scheme employs pilot point methodology and a kriging updating scheme that perturbs the model parameters (reservoir permeability, for example) only at selected pilot locations and then transfers the resulting changes in properties to other locations by kriging estimation, This new inversion scheme has the advantages of significant improvement in computational efficiency and of conditioning reservoir models to production data while preserving the structure of initial models derived from static data. Furthermore, it offers flexibility in selecting pilot locations based on prior knowledge of the reservoir. The application of structure preserving inversion to synthetic and field case studies demonstrates its capability of honoring multiphase production history while preserving major structure of initial models and its capability of handling large-scale reservoir models. |
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| Item Description: | Vita. "Major Subject: Petroleum Engineering". |
| Physical Description: | xvii, 165 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 141-146. |