masterThesis
Incrustação em poço produtor de petróleo e gás natural: um estudo de caso
Fecha
2009-07-24Registro en:
FROTA, Tarcila Maria Pinheiro. Incrustação em poço produtor de petróleo e gás natural: um estudo de caso. 2009. 100f. Dissertação (Mestrado em Ciência e Engenharia de Petróleo) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2009.
Autor
Frota, Tarcila Maria Pinheiro
Resumen
Water and gas is a common
by
-
product
of the oil production process. Production may be
compromised by the precipitation of inorganic salts in both the reservoir and producing well,
through scale formation. This precipitation is likely the cause of the formation damage. High
temperatures and h
igh pressures (HTHP) may favor the precipitation of insoluble salts. The
most common types of scale in oil fields are calcium carbonate and calcium sulphate,
strontium and barium sulphate. New types of
scale formation
have attracted special attention
such
as zinc sulphide and lead. This precipitation may occur in the pores of reservoir rocks, in
the production string and in equipment, causing obstructions and consequent production
losses. In this study, the influence of well depth on incrustation compositio
n was investigated
to design removal treatments and assess the behavior of these deposits along the string,
through the analysis of pressure and temperature. Scale residues were recovered from the
inside of the production string of an oil and gas well duri
ng the string removal operation. A
total of 10 samples from different depths (15.4
m to 4061.5
m) were obtained.
Initially a
dissolution test was conducted in weak acid, similar to that used in removal operations with
this type of scale formation. Majority
composition was defined and confirmed by dissolution
tests using X
-
Ray Fluorescence Spectroscopy (XRF), X
-
Ray Diffraction (XRD) and Scanning
Electron Microscope (SEM) techniques. Residues with distinct characteristics were observed
in different proportion
s, showing a tendency toward increased and/or decreased mass with
depth. In the samples closest to the surface, typical sandstone residues were found, with
calcium (45% Ca) as the metal of highest concentration.
The obtained results indicate
correlations o
f the
scale
types studied with the
depth
and, consequently, with the
thermodynamic conditions of pressure and temperature.