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Search wellbore seismic: 4.3.3 Solids
... (1 ) [ ( ) ] = (2 ) ( 2 ) ( ) (2 ) 3 = + 4 (3) + 4 3 + + ...3 (+ ) = 1 [1 + 8 + 2 2 ] (4) 5 4 +( +2 ) + 4 3 ...
... The Rock Physics Handbook: Tools for Seismic Analysis of a cracked solid, International Journal of Solids and of Porous Media (2nd ed.), Cambridge: Cambridge Structures, 12, 81-97. University Press. http...
ABSTRACT Pore structure characterization has always been challenging, especially in carbonate rocks. Acoustic and nuclear magnetic resonance (NMR) measurements have been employed to characterize different aspects of pore geometry. In this study, we combine both for an improved and quantitative characterization of carbonate rock pore structure. The method developed includes that we first calculate the volume fractions of crack pores (microcracks and microfractures with a low aspect ratio α), reference pores (interparticle pores with a medium α), and stiff pores (moldic and vuggy pores with an α close to one) through the inversion of an effective medium rock physics model using acoustic compressional and shear measurements. We then add the micro- and macroporosities inferred from NMR interpretation to determine the volume fractions of six pore groups (microcrack, micro reference, micro stiff, macrocrack, macro reference, macro stiff) by joint inversion. We finally calculate the semi-long axis (a), semi-short axis (c), and cross-section area index (ac) for the six pore groups. As an example of applications of rock pore structure characterization, the derived pore geometry parameters are used along with porosity to build a model for permeability estimation after it calibrated with core data. This method was tested with log data and demonstrated promising results for carbonate pore system characterization. Total porosity is partitioned based on the six pore types with corresponding pore body sizes of a and c. Comparisons with interpretation from borehole images and core analysis data present consistent results. Subsequent pore geometry parameter-based permeability estimations showed improved performance compared to conventional methods, confirming that the integration of NMR and acoustic data enhances understanding of carbonate rock characteristics. INTRODUCTION Carbonates are important hosts for hydrocarbon reservoirs, making up almost 60% of the world's proven reserves as per BP Statistical Review of World Energy (BP, 2022). Carbonate reservoirs differ significantly from siliciclastic reservoirs due to different depositional environments and complicated diagenetic processes. The intense diagenetic history can alter the mineralogy and texture of the original framework, causing carbonates to exhibit wide variations in pore types, such as interparticle, intercrystalline, moldic, vuggy, intraframe, and microcrack. This makes pore structure characterization difficult and, consequently, evaluating reservoir properties such as permeability estimates and establishing relationships between rock properties such as porosity vs. permeability challenging (Ma and Morrow, 1996).
- North America > United States (1.00)
- Asia > Middle East > Saudi Arabia (0.69)
- Research Report > New Finding (0.48)
- Personal > Honors (0.46)
- Research Report > Experimental Study (0.34)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)