Here's why:

* The core is too hot and under immense pressure: The Earth's core is a solid ball of iron and nickel, incredibly hot (around 5,200°C or 9,392°F) and under enormous pressure. This environment is not suitable for the formation or preservation of oil, gas, or other resources.

* Oil and gas form in sedimentary rocks: Oil and natural gas are formed over millions of years from the decomposition of organic matter, like ancient plants and animals, buried under layers of sediment. This process happens in sedimentary rocks, which are found much closer to the Earth's surface than the core.

* Geologists explore sedimentary basins: Geologists primarily focus on sedimentary basins, areas where layers of sedimentary rocks have accumulated over time. They use various techniques like seismic surveys, drilling, and analysis of rock samples to locate potential oil and gas deposits.

In short, while the core is an incredibly important part of the Earth's structure, it's not a place where geologists would look for oil, gas, or other resources.