While cash was flowing in from Silicon Valley and other tech hubs, the oil fields of West Texas were also booming. Money from Houston, the corporate epicenter of the U.S. oil industry and just a two and a half hour drive, has also been instrumental in greasing Austin’s tech economy. Directly, the oil boom has attracted some 300 companies to Austin, working across oil investment and finance, surveying, drilling technology, and production. Houston-based VCs, such as Cottonwood Technology Fund, and the corporate venture arms of oil compan…