1 Application of FIB/SEM and Argon Ion Milling to the Study of Foliated Fine Grained Organic Rich Rocks Carl H. Sondergeld, Mark E. Curtis and Chandra S. Rai Mewbourne School of Petroleum and Geological Engineering University of Oklahoma Norman, Oklahoma 73019 Abstract Adopting any new technology involves a learning curve. We review development experiences and challenges in producing images of shales using FIB/SEM technology. 2D imaging identifies the elements of shale but cannot address their distribution in 3D. The advantage FIB/SEM offers is the ability to capture and analyze the 3D structure of shales. It allows us to identify and quantify the connectivity of the structural elements and pores. This is facilitated through the segmentation of 3D volumes of organic matter and pores. The geometries of pores, grains and organics provide the basis for constructing three dimensional flow and structural modeling. Introduction: A major resource of natural hydrocarbons is found in extremely fine grained, strongly foliated rocks rich in organic materials. The fine grain size, typically less than 1 m, means that the associated pore size is even smaller. For simple cubic packing of spherical particles, the largest inscribed sphere is about one half the size of the particle. However, the empirical relation between pores and grains is typically 1 to 10; pores are about 1/10 the diameter of grains. We begin our investigations looking for 100 nm size pores. Pores are of interest because these provide the storage and transport of hydrocarbons. These 100 nm sized pores are easily imaged using scanning electron microscopy. The challenge is twofold: 1) sample preparation which does not create artifacts and preserves the intrinsic structures of pores and grains, and 2) reconstructing the 3D structure from representative 2D images. The ability to create 3D images allows the assessment of pore connectivity and continuity. A real challenge we face with these nano- and micro- scale imaging capabilities is establishing how representative they are. These rocks come from reservoirs which have aerial dimensions of tens to hundreds of square miles and hundreds of feet in thickness. Statistical representation requires high throughput without sacrificing quality and adequate geologic sampling Sample preparation: The conventional approach to sample preparation in the oil and gas industry is to simply break a fresh surface, sputter coat with carbon or gold-palladium and image (see Fig. 1).