Stephen Farrington, PE (Transcend) SCIMPI Overview Kate Moran, PhD, PE (URI) Stephen Farrington, PE (Transcend) Jim Newman, (WHMSI) Ian Kulin, PE (URI) Tania Lado Insua (URI)

SCIMPI Program Summary Funded by IODP as a complement to the CORK where appropriate Objective is to develop an inexpensive seafloor observatory system installable in unlined IODP boreholes Based on modular design Included in several IODP proposals

SCIMPI Team University of Rhode Island – Overall development and deployment Transcendev – Module design and prototype construction Woods Hole Marine Systems, Inc. – Development of buoyant cable from SCIMPI to command module Stress Engineering – Deployment tools and procedures Lamont-Doherty Borehole Research – Deployment tools and testing assistance

SCIMPI: Simple Cabled Instrument for Measuring Parameters In-Situ Modular instrument design enables sensor emplacement at custom depth intervals Deployable through IODP drill string directly into borehole without re-entry or a ROV Eventual borehole collapse provides contact with formation Powered via cable or modular battery packs When not cabled to an observatory, data are retrievable via ROV

SCIMPI From the Bottom Up 500-lb “pig” maintains cable tension, is sensible to winch operator Structural cable Measurement Modules with Intervening Buoyant Cable ROV-serviceable wet-mate connector Cable from the wet-connect to Cabled observatory infrastructure or Command Module Buoyancy (syntactic foam beads) maintains cable tension, keeps wet-mate connector and Command Module above seafloor while the drill pipe is “stripped” Buoyancy

SCIMPI Pressure Housings Modular scheme Design pressure 60 Mpa (8760 psi) Testing to 72 Mpa (10,500 psi) Chamber dimensions Inner diameter: 60mm (2.375”) Outer diameter: 76.2mm (3.0”) Inner length: 235mm (9.25”) Material 17-4PH Stainless, condition H1025 Unfilled PEEK for electrical insulation FEA performed as design precaution

SCIMPI Datalogger Controls power to and commands measurement modules Auto mode sensing and switching: Deployment vs. In Situ Deep sleep mode <165 μA @ 1.8v Leverages .NET Micro Framework Includes file system, RTC, DIO, SD card driver, UARTS ROV exchangeable

SCIMPI Sensors Pressure: Paroscientific 401k-101 DigiQuartzTM sensor (0-10k psi, ppb accuracy) Temperature: Sea-Bird SBE-38 precision oceanographic thermometer Resistivity: custom Wenner 4-electrode cell and precision electronics Modular design enables additional sensors

SCIMPI Sensor Arrangement Pressure Sensor Port Precision Thermometer Resistivity Contacts

SCIMPI 3rd Party Sensors Temperature: Sea-bird SBE-38 Range: -5 to +35 °C Absolute accuracy: 0.001 °C Resolution: 0.00025 °C Drift: <0.001 °C in 6 mos. Pressure: Paroscientific 410k-101 Range: 0-10,000 psi (0-69MPa) Accuracy: 1 psi (6.9 kPa), 0.01% FS Resolution: 0.1 psi (690 Pa)0.0001% FS

SCIMPI Resistivity Sensor Wenner style 4-electrode configuration Custom circuitry μ-Processor controlled Cell constant: 1 cm-1 Electrodes of 316 SS PEEK insulating material Parts per million precision Calibration to NIST traceable standards

SCIMPI Battery Packs 14.4v, 25Ah per pack Packs are shared in parallel Lithium thionyl chloride primary cells Dimensions Length: 203mm (8.0”) Circumscribed diameter: 56mm (2.2”) Each pack designed to power: Entire SCIMPI for 1 yr (at 20°C) One measurement module with Pressure for 5+ yrs (at 20°C)

Approximate SCIMPI Equipment Costs (US$) Measurement Module (with buoyancy): $30k w/pressure, $20k w/o pressure Borehole Cables $3000 ea plus $30 per meter Command Module $20k Wet Connect ~$30k per assembly Example: 7 Measurement Modules plus Command and 300m of cables, ~$350k