Casing influence in reservoir compaction measurement by radioactive markers
in the Northern Adriatic, Italy
M. Ferronato, G. Gambolati, P. Teatini, C. Janna
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
ABSTRACT
The reliability of in situ compaction measurements made in producing gas/oil
reservoirs with the aid of the radioactive marker technique (RMT) is a very
important issue as an essential parameter controlling the geomechanical
response of fluid extraction from the subsurface, i.e., the rock vertical
compressibility cM, is obtained from RMT data. The validity
of cM as provided by RMT has recently
been questioned on the basis of the possible disturbance that a fully cased
hole can induce on the actual reservoir compaction. By the use
of a numerical approach and real casing information, the present paper addresses
and discusses the reliability of RMT measurements performed in hole casings of
the Northern Adriatic gas fields, Italy. The results show that the casing
stiffness affects the RMT measurements only marginally, and especially so at a
larger depth (i.e., 3,000 m), and does not significantly impact on the estimate
of cM derived from RMT data.
