Processing and analysis of transient pressure from permanent down-hole gauges
Abstract
With the permanent down-hole gauge (PDG) widely installed in oilfields around the
world in recent years, a continuous stream of transient pressure data in real time are
available, which motivates a new round of research interests in further developing
pressure transient analysis techniques.
PDG data is recorded under the unconstrained circumstances, so that it cannot avoid
effects due to noise, rate fluctuation and interference from other wells. These effects
make the measured pressure trends declining or rising and then obscure or distort the
traditional flow behavior, which makes the following analysis difficult.
In this thesis, the problems encountered in analysis of PDG transient pressure are
investigated. A new algorithm, multi-well deconvolution, and corresponding computer
codes are developed. The algorithm is based on linear recursion with added non-linear
least squares optimization to deal with the noise problem in time domain. With this
developed algorithm, the inter-well interference effect can be extracted and the
variable-rate superposition effect can be solved at the same time. New
deconvolution-based rate transient analysis and pressure transient analysis methods are
both proposed in this thesis. Numerical well testing synthetic studies are performed to
demonstrate these procedures. The results prove that the new method works well in
homogeneous reservoirs with two wells flowing at single phase, multiple rates.