Depositional Porosity and Permeability Calculated from Modern Carbonate Sediments, Turks and Caicos Islands, British West Indies
Published:January 01, 2008
Gareth D Jones, David N. Awwiller, 2008. "Depositional Porosity and Permeability Calculated from Modern Carbonate Sediments, Turks and Caicos Islands, British West Indies", Developing Models and Analogs for Isolated Carbonate Platforms—Holocene and Pleistocene Carbonates of Caicos Platform, British West Indies, William A. Morgan, Paul M. (Mitch) Harris
Download citation file:
Accurate estimates of depositional porosity and in particular permeability are critical initial inputs for process-based models used to predict diagenesis in carbonate reservoirs. Unfortunately, the depositional porosity and permeability of modern carbonate sediments have rarely been measured. In this study, porosity and permeability, using Kozeny-Carman and Lattice-Boltzman algorithms, were calculated on simulated grain packs built from grain-size analyses of carbonate sediments.
Five depositional environments on the Caicos Platform were sampled: Tidal Flat, Lagoon, two different Shoals, and Beach. Sediments were analyzed for texture, composition, mineralogy, grain size, and sorting. The depositional environments sampled have a characteristic grain-size distribution and the mean grain size for individual sample locations was relatively uniform. Porosities calculated for grainstones (0.39 to 0.42) were lower than those measured in a separate study on the Great Bahama Bank (0.5 to 0.53). Porosity calculated for tidal-flat sediments (0.31) is significantly lower than measured values (0.61 to 0.78) because intragranular porosity is not calculated. Depositional permeability calculated for grainstones with Lattice-Boltzman (290 to 531 darcies) was greater than with Kozeny-Carman (137 to 285 darcies). Values of permeability for ooid grainstones measured on the Great Bahama Bank (16 to 57 darcies) are an order of magnitude lower, but those sediments are also finer grained (200 versus 700 microns mean grain size).
Figures & Tables
Developing Models and Analogs for Isolated Carbonate Platforms—Holocene and Pleistocene Carbonates of Caicos Platform, British West Indies
Developing Models and Analogs for Isolated Carbonate Platforms-Holocene and Pleistocene Carbonates of Caicos Platform, British West Indies - For the past 30 years, Caicos Platform has been an important area for studies of Holocene and Pleistocene carbonate successions and a destination for numerous geoscientists interested in learning about modern carbonate sedimentary systems. During the past few years there has been a renewed interest in understanding the geology of the platform, stemming in large part from recognition in the petroleum industry that more refined reservoir models of carbonate systems are needed both in exploration and development. The impetus for the workshop and the publication was a desire to bring together both present and past Caicos Platform workers with those not familiar with the Platform to share knowledge on the Holocene and Pleistocene Sedimentology, diagenesis, platform evolution, and the applicability of the platform as an analogue for ancient isolated carbonate platforms. This volume should serve as an intermediate-term documentation of research efforts and a spur for additional studies to better understand controls on sediment distribution, diagenesis, and the evolution of platform growth, furthering the Caicos Platform as an analogue for ancient, isolated, carbonate platforms.