Well first thing to do is remove Libreoffice if its installed. Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command(s) below:
sudo apt-get remove --purge libreoffice*
sudo apt-get clean
sudo apt-get autoremove
Then to install OpenOffice you do:
sudo add-apt-repository ppa:upubuntu-com/openoffice
sudo apt-get update
sudo apt-get install apache-openoffice
I just tested it on 13.04, and it works.
For Ubuntu 14.04 and above download either the 32bit or 64bit of Apache OpenOffice.
For 32 Bit:
wget http://sourceforge.net/projects/openofficeorg.mirror/files/4.1.3/binaries/en-US/Apache_OpenOffice_4.1.3_Linux_x86_install-deb_en-US.tar.gz
tar xzf Apache_OpenOffice_4.1.3_Linux_x86_install-deb_en-US.tar.gz
For 64 Bit:
wget http://netassist.dl.sourceforge.net/project/openofficeorg.mirror/4.1.3/binaries/en-US/Apache_OpenOffice_4.1.3_Linux_x86-64_install-deb_en-US.tar.gz
tar xzf Apache_OpenOffice_4.1.3_Linux_x86-64_install-deb_en-US.tar.gz
once extracted, navigate to the DEBS folder where the file was extracted, and issue the command(s) below:
cd en-US/DEBS/
sudo dpkg -i *.deb
Then navigate to the desktop-integration folder, and issue the command(s) below:
cd desktop-integration/
sudo dpkg -i openoffice4.0-debian-menus*.deb
Source for OpenOffice Install:Upubuntu