Abstract

Rudists are a group of bizarrely shaped marine bivalves that lived inthe Tethys Ocean from the Late Jurassic to the latest Cretaceous. They aremorphologically variable, including snail-like, cup-like, and horn-like shapes. Inthe Middle East, Cretaceous carbonates with rudists and rudist fragments are wellexposed in many outcrops as well as oil and gas fields. For rudist-bearingcarbonates in the subsurface, knowledge of rudist morphology and mode of occurrencemust be derived from observation of drillcores; however, understanding thethree-dimensional (3D) geometry of rudists from observation of core surfaces isdifficult. In paleontological studies of rudists, X-ray computerized tomography (CT)scans have been carried out to reconstruct the inside texture of rudist shells forthe purpose of taxonomic research. In contrast, in the oil and gas industry,application of X-ray CT scanning technology is generally focused on directmeasurement of reservoir properties. Studies of rudist fossils within drillcores bymeans of X-ray CT have not yet been conducted. We have developed a new protocol toobserve core interiors using X-ray CT. We obtained high-resolution 3D images ofrudists in a drillcore by means of surface rendering, volume rendering, and 3Dprinting. X-ray CT and 3D modeling is a novel method for non-destructive analyses ofthe morphology and mode of occurrence of fossils within drillcores.