A Deepwater Sandface Monitoring System for Offshore Gas Hydrate

Abstract

The world's first offshore gas hydrate production was successfully carried out in the deepwater Japan at Nankai Troughin Q1 2013. In this project, one production well and two sandface monitoring wells were drilled and installed with a combination of distributed temperature sensing (DTS) and array-type RTD (Resistance Temperature Detector) sensors. The objective of the sandface monitoring system was to capture the hydrate dissociation front dynamically changing during the production test and to monitor long-term reservoir stability with the selected temperature sensors. An ability to continuously monitor the response of these temperature data during production test would facilitate tracking of the dissociation front and yield valuable information for engineering design and verification of numerical reservoir simulators. The temperature sensors are cemented behind the casing and also strategically installed to cover the hydrate zone of interest and the entire wellbore. Due to operational constraints, the monitoring system was designed to be autonomous self-operated system by the subsea battery without cable connection from the sea surface for a period of 18 months from the day of installation of the monitoring system. The deployment of this monitoring system in this shallow unconsolidated hydrate reservoir was an unprecedented and challenging operation. In this paper, we will show the details of the key system components of the sandface monitoring system and the deployment process.

Fine Particle Migration in a Gas Hydrate Sand: Single- and Two-Phase Fluid Using a Device for Observation at the Pore Scale

“…The values of H are H = 0.63 × 10 −20 J in water and H = 6.5 × 10 −20 J in air [39], respectively. The F vdw_water and F vdw_air can be calculated based on Equation (8) and are listed in Table 4.…”

“…As production-induced hydrate dissociation causes 2 of 29 de-cementation and enlargement of voids in the matrix of reservoirs, fine particles become mobile and likely migrate with fluids towards the wells under a high-pressure drop, causing damage/malfunction in the wells and production shutdown. The destructive impact of sand production is reported in trial production implemented in the Nankai Trough of Japan [6][7][8][9][10][11] in addition to other inland hydrate reservoirs [12][13][14][15]. Therefore, effective sand control is vital for achieving sustainable long-term operation, while understanding the fundamental behavior of fines that migrate through pore networks is a prerequisite.…”

A review on the methane emission detection during offshore natural gas hydrate production

“…Image (B) illustration of the seafloor observatory at the Woolsey Mound (Mississippi Canyon Lease Block 118, MC118) in 2012 (Macelloni et al, 2012). Image (C) production and monitoring systems at Nankai Trough in 2013 (Chee et al, 2014).…”

A Multi-electrode Resistivity Logging Design to Monitoring Natural Gas Hydrate Reservoir Decomposition

“…It is necessary to monitor the decomposition state of hydrate reservoir in real time during exploiting in order to guarantee the project security. At present, this project is mainly achieved by measuring the variation of temperature and pressure in different positions of producing well or monitoring well [2] . However, such indirect method cannot describe the spatial distribution in the decomposition area of hydrate.…”