Simply use that project's pip
to install desired module.
In your case, for example:
user/.pythonbrew/venvs/Python-2.7.6/project1/bin/pip install mpipe
Dump the newly installed module's version:
user/.pythonbrew/venvs/Python-2.7.6/project1/bin/python -c 'import mpipe; print(mpipe.__version__)'
Output is:
1.0.7