The goal of this project is to define, plan, and conduct a field trial of a methane hydrate production methodology whereby carbon dioxide (CO2) molecules are exchanged in situ for the methane molecules within a hydrate structure, releasing the methane for production. The objective is to evaluate the viability of this hydrate production technique and to understand the implications of the process at a field scale.
Under this project, ConocoPhillips plans to perform the first field trial of this promising, sustainable, methane hydrates production technology at a site on the Alaska North Slope (ANS). Operations were conducted from a 500ft x 500 ft ice pad adjacent to the PBU L-Pad access road.
- The surface hole drilled, using water-based mud and logging-while-drilling (LWD) measurement, to a depth of 1,482 ft and then cased, cemented and pressure tested.
- The remainder of the well was drilled (with LWD) to total depth of 2,597 ft using oil-based mud.
- Wireline logs were obtained including: gamma-ray, resistivity, high resolution density, neutron porosity, oil-based mud imaging, combinable magnetic resonance, sonic scanner and borehole resistivity scanner.
- Short duration tests were conducted using Schlumberger’s Express Pressure Tool (XPT) and Modular Formation Dynamic Tester (MDT).
- Lower well completion included installation of an instrumented casing string with downhole temperature and pressure gauges and a continuous, fiber optic distributed temperature sensor.
- Upper well completion included installation chemical injection and gas lift mandrels.
- Freeze protection was implemented and the well temporarily suspended in preparation for anticipated re-entry during a subsequent winter drilling season.
Data and Analysis
Logging results indicate four gas hydrate-bearing sand horizons in the well (in accordance with pre-drill predictions) including a 144 ft thick zone of clean, high-porosity sandstone with high gas hydrate saturation in the Sagavanirktok “Upper C”, which represents optimal pressure-temperature conditions for conducting the planned field trial. The XPT tool successfully acquired data that will yield insight into ambient reservoir pressure and potential injectivity of various stratigraphic units. The MDT tool was used primarily to conduct tests designed to measure formation breakdown pressures.
The project is now focused on review of the geologic, petrophysical and engineering data from the 2011 field program which will be used to determine optimal parameters for future production related field trials. Current plans are to return to re-enter the well, from a smaller ice pad, during the next winter drilling season. The testing program will consist of CO2 injection and shut-in for exchange with methane to be followed by stepwise depressurization and flowback. Once the exchange test objectives are met, the intent is to use the wellbore for continued production testing, including extended depressurization, potentially through the end of that winter season.1
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Planned Total Funding :
DOE Contribution: $20,945,125 ($9,869,506 obligated to date)
Performer Contribution: $5,337,173
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