Beard D.C., and P. K. Weyl, 1973, Influence of texture on porosity and permeability of unconsolidated sand: AAPG Bulletin, v. 57, p. 349-369.
This classic paper was the first major attempt to quantify the effects of grain size and sorting on porosity using artificially mixed and packed sand samples. They found that regardless of grain size, the porosity of "wet-packed" samples with similar sorting was the same, whereas porosity decreased significantly for sands with varied sorting. They also provided quantitative data relating the effect of grain shape (sphericity) and roundness (angularity) to porosity which suggests that low sphericity and high angularity increases porosity of unconsolidated sands. This work provided the foundation for our current treatment of texture in predictive modeling programs. 696 citations.
Heald, M. T., and R. E. Larese, 1974, Influence of coatings on quartz cementation: Journal of Sedimentary Petrology, v. 44, p. 1269-1274.
Clay grain coatings were observed to often be effective in preserving porosity by inhibiting the development of quartz cement. But, this study went one step further by suggesting that a variety of mineral coatings (clay, hematite, chert), fractures, and crystal orientation could impact quartz cementation. The relative effectiveness of various minerals in inhibiting quartz cement was found to be chlorite > illite > chert and carbonate > hematite and changed our way of thinking about controls on cement development in sandstones. 161 citations.
Folk, R. L., 1968, Petrology of sedimentary rocks: Hemphill's, Austin, Texas, 170 p.
Since its initial printing, the "Folk Orange Book" has provided a timeless reference guide for generations of sedimentary petrologists to understand and evaluate diagenesis in sedimentary rocks (sandstones and carbonates). This book doesn't just provide tips on how to identify key framework grains (quartz, feldspar and lithics), but pioneered our understanding of the importance of global controls on sandstone composition, such as provenance, tectonics, and depositional environments etc. The Folk QFL diagram remains one of the primary ternary diagrams still in use today. Folk also stressed the use of statistics in evaluating texture, including the use of standard deviation to define sorting. This technique (referred to as Folk sorting) is still widely used. Reprinted in 1980 and 2000 – a true classic. 5141 citations.
Wilson, M. D., and E. D. Pittman, 1977, Authigenic clays in sandstone: recognition and influence on reservoir properties and paleoenvironmental analysis: Journal of Sedimentary Petrology, v. 47, p. 3-31.
Prior to this paper, it was widely assumed that most clay was of detrital origin and that sand composition and texture were the primary controls on reservoir quality. However, this paper changed our views forever, by highlighting the importance of authigenic clay (clay formed in-situ) and its impact on reservoir properties. Using a dataset consisting of over three thousand samples from a wide range of environments and ages, they clearly and concisely described the challenges, but critical importance, of differentiating allogenic versus authigenic clay. They emphasized an integrated approach to clay mineral identification which included not just X-ray diffraction, but also thin section and SEM/EDS analyses. Their work also stressed the importance of documenting clay morphology and distribution, in order to understanding variations in permeability and water saturation. Lastly, the paper provided practical criteria and stunning SEM images which documented for the first time, the morphologic differences between common authigenic clays, iron oxide and cristobolite cements. 388 citations.
Boles, J. R., and S. G. Franks, 1979, Clay diagenesis in Wilcox sandstones of southwest Texas: implications of smectite diagenesis on sandstone cementation: Journal of Sedimentary Petrology, v. 49, p. 55-70.
Prior to publication of this paper, pressure solution was believed to be the dominant process which created quartz cement. Building on the newly published work of Hower et. al., 1976, they showed that the formation of authigenic cements (e.g. quartz, clay and carbonates) was actually linked to sand/shale interactions over a broad range of burial conditions in the lower Eocene Wilcox Formation, TX. For example, the breakdown of K-feldspar and the transformation of illite/smectite (60-120°C) released silica to form quartz overgrowths, calcium to form carbonate cements, and at higher temperatures (>125°C), iron and magnesium to form iron-rich chlorite and/or ankerite. This emphasis on the importance of the by-products (i.e. ions in solution) of clay diagenesis reactions in sandstone cementation, changed our way of thinking about sandstone cementation and also introduced the idea that burial history data (temperature and pressure) could be used to define cementation events. 832 citations.
Walderhaug, O., 1996, Kinetic modeling of quartz cementation and porosity loss in deeply buried sandstone reservoirs: AAPG Bulletin, v. 80, p. 731-745.
Modern predictive diagenetic modeling became a reality with the publication of this classic paper which introduced the idea that a simple kinetic model could be used to simulate quartz cementation and the resulting porosity loss, as a function of temperature. Prior to this, workers generally assumed quartz cementation was episodic with the dominant source being pressure solution. In this paper, quartz cementation was modeled as a continuous precipitation rate-controlled reaction where the quartz precipitation rate per unit time and surface area and was expressed as an empirically determined logarithmic function of temperature. The integration of this quartz cementation algorithm with a compaction algorithm provided the first hope that a porosity prediction tool could be designed for explorationists working in quartzose sandstone reservoirs. 254 citations.
Lander, R. H., and O. Walderhaug, 1999, Porosity prediction through simulation of sandstone compaction and quartz cementation: AAPG Bulletin, v. 83, p. 433-449.
Building on the previous work of Walderhaug (1996), this key paper further described advances in the development of a hybrid forward numerical model for predicting the evolution of sandstone porosity through geologic time. Using sandstone composition and texture data from point count analyses, combined with burial history data, their reservoir quality forward model program simulates the rate of porosity reduction due to compaction and cementation through time, using the appropriate compaction and quartz cementation parameters derived from calibration studies. The paper not only described in detail their model design, but also discussed how the results could be used by the explorationist including the use of Monte Carlo techniques to provide enhanced probabilistic reservoir quality predictions. Examples of porosity predictions from the Gulf of Mexico, North Sea, Illinois Basin and Baltic region that were consistent with measured core porosity, intergranular volume and quartz cement values illustrate the tremendous advances in reservoir quality prediction that have occurred in the past few decades. 194 citations.
Heald, M. T., and J. J. Renton, 1966, Experimental study of sandstone cementation: Journal of Sedimentary Petrology, v. 36, p. 977-991.
Heald's brilliant experimental studies were showcased in many key papers, including this classic where he used hydrothermal reactors to study the impact of physical properties such as texture, angularity and variable quartz composition on cementation and porosity reduction for a range of temperatures and pressures. The methodology and results were clearly described and documented. They showed that quartz overgrowths could be created in the laboratory under controlled conditions that were similar in morphology to natural overgrowths. This work not only advanced our understanding of sandstone cementation but inspired generations of future experimentalists. 161 citations.
Welton, J. E., 1984, SEM Petrology Atlas: AAPG Methods in Exploration Series No. 4, 236 p.
In the late 1970's, geologists in industry and academia began using the Scanning Electron Microscope/Energy Dispersive X-ray (SEM/EDS) to look at rocks; however, there was no reference material to help with the identification of the common minerals found in sandstone reservoirs. The management of Chevron Oil Field Research Company in 1978 recognized this problem and funded an internal research project to create a comparative atlas for Chevron geoscientists. In 1982, AAPG approached Chevron and asked if they could publish this atlas (using newly developed laser printing techniques) to promote the use of the SEM/EDS in geologic studies. Now over thirty years later, this atlas continues to be a key reference for students and industry professionals worldwide. 198 Citations.
Hower, J. E., E. Eslinger, M. E. Hower, and E. A. Perry, 1976, Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogical and Chemical Evidence: GSA Bulletin, v. 87, p. 725-737.
This pioneering work on shale cuttings was the first to recognize that major mineralogical and chemical changes occur in clay minerals due to burial metamorphism at a the depth range from 2000m to 3700m. Using detailed X-ray diffraction studies on Oligo-Miocene sediment from the Gulf Coast of the U.S., they observed that illite/smectite (the dominant clay mineral) underwent a conversion from less than 20 percent illite to 80 percent illite in this depth interval, whereas calcite and K-feldspar (not albite) decreased to near zero and chlorite increased. They concluded that shale acts as a closed system for all components except H2O, CaO, Na2O and CO2. They also hypothesized that increased amounts of potassium and aluminum were most likely derived from the decomposition of potassium feldspar (and mica?) and that the excess silica generated formed quartz overgrowths. 1225 Citations