About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

AAPG Bulletin, V. 101, No. 1 (January 2017), P. 73-94.

Copyright ©2017. The American Association of Petroleum Geologists. All rights reserved.

DOI: 10.1306/06101616034

Facies-independent reservoir characterization of the micropore-dominated Word field (Edwards Formation), Lavaca County, Texas

S. Van Simaeys,1 B. Rendall,2 F. J. Lucia,3 C. Kerans,4 and S. Fullmer5

1ExxonMobil Upstream Research Company, 22777 Springwood Village Parkway, Houston, Texas 77389; [email protected]
2ExxonMobil Upstream Research Company, 22777 Springwood Village Parkway, Houston, Texas 77389; [email protected]
3Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78713; [email protected]
4Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78713; [email protected]
5ExxonMobil Upstream Research Company, 22777 Springwood Village Parkway, Houston, Texas 77389; [email protected]

ABSTRACT

Micropore-dominated carbonate reservoirs remain challenging for accurate hydrocarbon evaluation and production because conventional reservoir models using depositional textures and petrophysical properties to distribute porosity and permeability cannot be applied. Nevertheless, understanding the distribution of pore systems and predicting the fluid flow behavior of microporous reservoirs is fundamental because micropores constitute a significant percentage of the total porosity and storage capacity. We present the results from an integrated study on the producing micropore-dominated Word field characterized by a facies-independent, diagenetically controlled pore system that approaches 100% microporosity. Four cored wells through the Albian Edwards Formation were described and correlated using stacking patterns and vertical facies trends; pore type characterization was done through thin section petrography, routine core analyses, scanning electron microscopy, and mercury injection capillary pressure data. This study is an example of a permeable reservoir in which intergrain pores are cemented during burial diagenesis and micropores, being more resistant to cementation, remain open to depths greater than 4000 m (13,000 ft). A unique relationship exists between porosity, permeability, median pore throat size, and microcrystalline textures, independent of facies and fabrics. Cumulative gas production data show there is a correlation between the total porosity and the structural position of the wells: wells high on the structure have the highest production. We demonstrate that an equally well–connected micropore network exists in mud-dominated rocks via the matrix and via grain-to-grain contacts in grain-dominated rocks. The here described intragrain micropore network through grain-to-grain contacts in cemented grainstones is a new carbonate flow path that will likely become more important as more unconventional carbonate reservoirs are explored.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].