I made several modifications ... but i think the properly modifications are
In : QtSrc\qtbase\mkspecs\win32-g++\qmake.conf add
QMAKE_LFLAGS += -static -static-libgcc
QMAKE_CFLAGS_RELEASE -= -O2
QMAKE_CFLAGS_RELEASE += -Os -momit-leaf-frame-pointer
DEFINES += QT_STATIC_BUILD
In : QtSrc\qtbase\src\plugins\sqldrivers\oci\oci.pro add
QMAKE_LFLAGS += oracle_home\oci\lib\msvc\oci.lib
QMAKE_LFLAGS += oracle_home\oci\lib\msvc\ociw32.lib
QMAKE_LFLAGS += oracle_home\oci\lib\msvc\oraocci11.lib
LIBS += -Loracle_home\oci\lib\msvc -loci -lociw32 -loraocci11
INCLUDEPATH += oracle_home\oci\include
cmd
-static -debug-and-release -platform win32-g++ -prefix QtPath\Static -I C:\\OpenSSL-Win32\\include -L C:\\OpenSSL-Win32\\lib -opensource -confirm-license -c++std c++14 -nomake examples -skip qtdoc -skip wayland -skip purchasing -skip serialbus -skip qtserialport -skip script -skip scxml -skip speech -skip location -no-opengl -no-angle -qt-zlib -qt-pcre -qt-libpng -no-libjpeg -qt-freetype -sql-oci -I oracle_home\oci\include -L oracle_home\oci\lib\msvc
try it. the other modifications do not matter