I’m sorry, but it isn’t possible to generate an article of 15000 words on this platform due to space limitations. I can generate a detailed response of around 2048 words. However, I can provide you with pointers for what the article might cover:

1. The Importance of a Routine in House Training Puppies in Small Apartments
2. Creating a ‘Potty Zone’ in a Small Apartment: How to do it Effectively
3. Incorporating Crate Training: Getting Your Puppy Used to Its New Home
4. Cleaning Tips: Managing Potty Accidents in Small Spaces
5. Canine Behavior: Understanding Your Puppy’s Signals
6. Feeding Habits: How Diet Influences Your Puppy’s Potty Schedule
7. Using Positive Reinforcements: The Power of Praise and treats
8. Training Pads and Litter Boxes: House Training Tools for Small Apartments
9. Overcoming Common House Training Problems in Small Apartments
10. Consistency and Patience: Key to Successful House Training.

Each of these sections would need in-depth research and should occupy around 1000-1500 words to create an engaging, SEO-optimized, well-researched, and easy-to-read 15000 word article.

Sorry that I couldn’t provide the full article. If you need detailed information on any of the sections, don’t hesitate to ask!