A status report on the IDDP was presented at the
Engine Workshop 2 in Volterra in April 2007. Since then,
two important developments have occurred.
Last month, the two PIs of IDDP reluctantly
recommended that the first deep IDDP well should be
rotary drilled to target depth (4.5 km) rather than
continuously core drilled between 3.5-4.5 km.
Secondly, an international aluminium company, Alcoa,
has now joined as a partner in the IDDP. As a
result, we now anticipate that drilling into a supercritical
reservoir in Krafla, NE-Iceland, will be realized late
summer or autumn next year, 2008.
To compensate for the lack of continuous core, a
reasonable number of spot cores should be collected
below 2.4 km to target depth. From the scientific
viewpoint continuous coring is much more preferable to
spot coring as it provides much better information
about the reservoir, about the nature of the fracture
system, about water-rock reactions, and allows
measurement of physical properties necessary for
calibration of geophysical interpretations. If total loss
of circulation occurs during drilling, coring it is the only
way to get rock samples as drill cuttings will not be
obtained.
Accordingly, spot coring is recommended in the event of
total circulation loss.
A balance needed to be struck between scientific
rewards, costs, and safety. Continuous coring is
inherently slower and more expensive than rotary
drilling and we have extremely limited experience of
continuous coring at very high temperatures.
Questions have been raised about the cooling of the
bottom hole assembly and its integrity at high
temperatures, that are still being debated amongst
drilling engineers. It is likely that these issues can only
be addressed by actual experience in continuous coring
at high temperature. At present, however, the chief
goal of IDDP is to drill into supercritical fluid and to
get it up to the surface for testing. Thus, in order to
lower the risk in drilling the hole and complete it sooner
for flow testing, we reluctantly recommended to
IDDP to delete the planned continuous coring in the
first IDDP well. There is a need for improved core drilling
technology, especially to improve the rate of
penetration which would result in lower drilling cost,
and to improve the cooling efficiency to meet hostile
environments of rock temperatures of 500-600°C.
Continuous coring should still be seriously considered in
the 2nd and/or the 3d IDDP well, which will be drilled at
Hengill and Reykjanes in SW-Iceland before 2010.
The main financial supporters of IDDP constitute the
Icelandic energy consortium, which is composed of
three leading Icelandic energy companies
together with the government of Iceland. Last month
negotiations with Alcoa proved positive for participation
in the energy consortium, Alcoa now becomes
the forth industrial partner in IDDP. In addition, the
International Continental Drilling Program (ICDP) and
the US National Science Foundation (NSF), have
sine 2005, allocated funds for scientific studies by
supporting considerable core drilling in the deeper parts
of the IDDP well(s). The plan is to seek additional
funds to the EC-FP7 for developing the engineering
pilot plant test of the supercritical fluid for power
production, likely to be needed in 2009-2010.
The poster shows the IDDP drillhole design, drilling
schedule and time plan. Drilling a fully cased and
cemented well to about 3.5 km is scheduled for
immediate deepening to ~4.5 km in 2008. After heat-up
period of unknown length, the drilling will be followed
by a major flow test and detailed chemical
study of the deep supercritical reservoir fluid, provided
we will find such fluid below 3.5 km depth. Most likely,
a mechanical and chemical engineering pilot
test will be needed before power production from
supercritical resources is realized. Discussions for
involving more international industrial partners in
IDDP are underway.
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