In order to evaluate the productivity of methane hydrate (MH) by the depressurization method, Japan Oil, Gas and Metals National Corporation and Natural Resources Canada carried out a full scale production test in the Mallik field, Mackenzie Delta, Canada in April, 2007. An extensive wire-line logging program was conducted to evaluate reservoir properties, to determine production/water injection intervals, to evaluate cement bonding, and to interpret MH dissociation behavior throughout the production. New open hole wire-line logging tools such as MR Scanner, Rt Scanner and Sonic Scanner, and other advanced logging tools such as ECS (Elemental Capture Spectroscopy) were deployed to obtain precise data on the occurrence of MH, lithology, MH pore saturation, porosity and permeability. Perforation intervals of the production and water injection zones were selected using a multidisciplinary approach. Based on the results of geological interpretation and open hole logging analysis, we picked candidate test intervals considering lithology, MH pore saturation, initial effective permeability and absolute permeability. Reservoir layer models were constructed to allow for quick reservoir numerical simulations for several perforation scenarios. Using the results of well log analysis, reservoir numerical simulation, and consideration of operational constraints, a MH bearing formation from 1093 to 1105 mKB was selected for 2007 testing and three zones (1224-1230, 1238-1256, 1270-1274 mKB) were selected for injection of produced water. Three kinds of cased-hole logging, RST (Reservoir Saturation Tool), APS (Accelerator Porosity Sonde), and Sonic Scanner were carried out to evaluate physical property changes of MH bearing formation before/after the production test. Preliminary evaluation of RST-sigma suggested that MH bearing formation in the above perforation interval was almost selectively dissociated (sand produced) in lateral direction. Preliminary analysis using Sonic Scanner data, which has deeper depth of investigation than RST brought us additional information on MH dissociation front and dissociation behavior.

My dissertation research consists of two themes: (a) the analysis of Middle Jurassic - Early Cretaceous marine magnetic anomalies (M-anomalies) in order to construct a comprehensive geomagnetic polarity timescale and (b) the investigation of the upper oceanic crustal architecture using downhole geophysical logs. These themes were chosen to better understand how remotely-sensed geophysical signals elucidate the formation and evolution of oceanic crust. This revised Pacific-wide MGPTS model shows significant improvement in its reliability, exhibits global applicability, and highlights changes in the paleo-Pacific spreading regime. By integrating Atlantic Manomaly analyses with the new MGPTS model and reviewing previous seismic studies, we shed new light on the causes of a ubiquitously distributed ?Atlantic anomaly smooth zone? where little coherency among M5-M15 anomaly sequence is observed. For the second theme, I analyzed the architecture of 15 m.y. old superfast spreading East Pacific Rise crust drilled at Ocean Drilling Program Hole 1256D in the eastern Pacific. An intact upper oceanic crustal section was penetrated at this site to a depth of 1507 mbsf. In situ crustal architecture was mapped from resistivity imagery (electrofacies by Formation MicroScanner) combined with recovered cores and other logs. Highlights of this research are: (1) most of the extrusive section consists of massive flows and fragmented formations including breccias, which has important implications for the magnetic source layer and pathways of hydrothermal alteration; (2) the dike complex is composed of sheeted-dikes dipping away from the paleo-spreading axis consistent with submersible observations at other sites in the eastern Pacific; (3) the crustal construction processess from ridge axis to abyssal plain during 0-50 kyr time are consistent with previous seismic reflection studies based on the integration of our stratigraphy model with lava flow observations from the southern East Pacific Rise.