Modeling Method to Characterize the Pore Structure of Fractured Tight Reservoirs

You Zhou,Junzhou Liu,Guangzhi Zhang

doi:10.3390/app12042078

You Zhou, Junzhou Liu + Show 1 more

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https://doi.org/10.3390/app12042078

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Abstract

The study of unconventional reservoirs has gained increasing attention with the deepening of exploration and development especially in deep-buried tight sandstone reservoirs. We could not obtain the accurate elastic parameters of reservoirs using the conventional rock physics model, since tight sandstone reservoirs have the characteristics of strong heterogeneity, complex lithology and storage space. In order to better describe tight sandstone reservoirs, we improved the traditional tight sandstone rock physics model by combining the dual-connected pore model and the linear slip model. Since the combined modeling process subtly considers four characteristics including the diversity of tight sandstone matrix minerals, the irregularities of pores structure, the connectivity between pores, and the anisotropy caused by fractures, multiple reservoir characteristic parameters can be derived from the limited logging information by the improved model. These reservoir characteristic parameters could account for the difference of diagenesis, which are useful to distinguish different pore types and eliminate ineffective reservoirs. The practical application shows that the improved model can extract microscopic reservoir information hidden in the logging data more effectively than the traditional model. It provides a reliable tool for identifying effective reservoirs in tight sandstone.

Highlights

While conventional reservoirs are still a very important part of the global energy supply, the progress in horizontal drilling and hydraulic fracturing technologies makes it possible to exploit unconventional reservoirs [1]
The rock physics model is the bridge between elastic parameters and subsurface rock physical properties, which have been proven to be a powerful tool for studying reservoir characteristics [3,4]
The relatiwonastehripinbtoettwheeernoctkhemvaetlroixcibtyasaenddopnotrhoesiMtyTomf tohdeerl,oacnkdsathmepnlecsalicnutlahteestthuedeylastic modulus area becomes voef rtyhecopmorpoluicsadterdy rboeccka.use the tight sandstone reservoirs have undergone a series of diageneticSttreapns3f.orAmdadtiotnhse. fFriagcuturere6ssihnotwo sththeedcrryo-srsocpklostkoeflePt-ownavuesivneglotchietyli(nVePa)r slip fracture versus porositmy iondtehl,eadnrdytrhoecnk csaalmcupllaetse. the effect of fracture on the dry rock elastic modulus

Summary

Introduction

While conventional reservoirs are still a very important part of the global energy supply, the progress in horizontal drilling and hydraulic fracturing technologies makes it possible to exploit unconventional reservoirs [1]. The rock physics model is the bridge between elastic parameters and subsurface rock physical properties, which have been proven to be a powerful tool for studying reservoir characteristics [3,4]. The pore structure of rocks is usually characterized in terms of the characteristics of their geometry, connectivity and size of stiff pores and micro-fractures. Due to the micro-scale and macro-scale heterogeneity of tight sandstone, there is no clear relationship between pore structure and physical properties of the rocks, which brings great difficulty to accurately estimating reservoir elastic parameters via rock physics models. In order to correctly explore the interrelations between different physical properties of rocks, it is essential to construct a practical rock physics models for tight sandstone

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Discussion

Conclusion