The influence of wave, tide and fluvial processes on shorelines varies considerably in and between coastal systems; this can result in the development of architecturally complex, mixed-process systems. Of these, tide-dominated systems produce some of the most heterogeneous deposits. The arrangement of reservoir elements generated by wave and fluvial processes in such tide-dominated systems can be, to some degree, systematic and predictable. This research details a modern, tide-dominated, fluvial-influenced, wave-affected coastal system. It presents geometric attributes for reservoir elements that can be used to improve the construction of 3D reservoir models of these depositional environments. The Mitchell River is the largest fluvial system, discharging into the low accommodation setting of the Gulf of Carpentaria. Its Holocene delta extends to more than 500 km2. Eleven types of depositional elements (n = 3,100) were mapped across the delta plain: 286 km2 of tidal, 133 km2 of fluvial and 101 km2 of wave elements make up the delta surface. Fluvially and wave-formed reservoir elements form systematic arrangements across the system. More than 75% of wave elements are aligned inside 45° of the shoreline and these are generally crescentic (asymmetric) or linear in shape. Fluvial elements are aligned either perpendicular to the shoreline, or alongshore, because they are trapped behind wave-formed, shore parallel features. Separate wave and fluvial reservoir element datasets demonstrate convincing, though distinctly different, length-to-width relationships; wave-formed elements are much longer than fluvial-formed elements, relative to their widths. Despite pronounced heterogeneity in the distribution of these depositional elements across the delta surface, these relationships suggest their distribution is, to some degree, predictable. Analysis of the connectivity of adjacent sandbody elements suggests the largest connected sandbody is significant and extends to more than 90 km2.

Data from satellite imagery, field measurements and analogues were used to construct a three-dimensional (3D) geocellular facies model of the Mitchell River Delta, Australia; a modern mixed-influence delta system. Detailed mapping identified 16 different facies elements and classified the delta as tide dominated, fluvially influenced and wave affected. The 3D model was subjected to varying degrees of upscaling of the horizontal and vertical dimensions and allowed comparison of volume and connectivity changes throughout. The upscaling process, to coarser grid cells up to 100 m horizontally and 4 m vertically, created false compartmentalization of facies bodies and significant changes in facies bulk volumes. The vertically upscaled models produced greater changes when compared to the horizontally upscaled models. Key changes in reservoir facies connectivity and bulk volume due to upscaling are associated with the facies architecture, including the elongate and thin morphology of beach ridge and channel facies in this mixed-influence delta system. Recognition of the defining reservoir features and incorporation into reservoir modelling methodology can improve volumetric estimation and allow for better predictions of reservoir connectivity in ancient delta systems.

A MEMS actuator, dubbed the MEMS hammer, capable of storing and rapidly releasing mechanical energy has been designed, built and tested. The hammer is fabricated using a single mask silicon-on-insulator (SOI) process. These devices have been used to study fracture in both lateral and vertical regimes. The lateral tests have shown excellent agreement with shear fracture theory. Using either a mechanical or an electrostatic latching mechanism, the hammers are capable of storing energies up to 3.3µJ. The hammers have been shown to displace up to 36µm, exert a maximum force of 240 mN, move at speeds exceeding 50m/s, and deliver at least 330 mW of mechanical power.