Wellbore cement integrity is paramount to safe,
successful oil and natural gas drilling. Cement acts as
the primary barrier between the wellbore and the
environment. An unstable cement can compromise
wellbore control, and research indicates that poor
cement integrity is a primary factor contributing
to loss of zonal isolation in oil and gas reserves.
Although cementing designs and placement
practices are well established in many operational
environments, the extreme subsurface conditions
found in deepwater oil and unconventional natural
gas reservoirs pose new challenges to achieving
reliable cement jobs.
With resource recovery in these types of reservoirs
on the rise, the National Energy Technology
Laboratory (NETL) and its partners in the NETLRegional
University Alliance (NETL-RUA) are
examining the performance and integrity of key
wellbore barrier materials for which data in extreme
environments are limited. One of those materials
is wellbore cement. Our researchers are working
to understand how various cement mixes perform,
with emphasis on potential failure pathways and
remediation technologies.
This work builds on long-standing research
conducted by our organizations to understand and
develop technologies for drilling systems associated
with onshore oil and natural gas development. It also
builds on our work in geologic CO2 storage, which
is looking at the effect of stored CO2, acid gas, and
brine solutions on the integrity of cements at high
pressure and temperature.
As the breadth and scope of cementing evolves and
industry drills toward deeper, more complex targets,
the initial and long-term integrity of cement barriers,
and the protocols for placing them, are critical to
safe, productive hydrocarbon recovery.
