The petroleum industry is becoming more technical with more discoveries. There are many different types of oil reservoirs in the subsurface. Many people imagine that oil is found in a type of "lake." However this is not the case. Oil or gas is found in the pore spaces of a formation. For this reason most of the oil and gas that has been recovered thus far has been in sandstone or limestone reservoirs. This is because they have a great deal of pore space that allows hydrocarbons to flow. However, in recent years hydraulic fracturing has become very popular in the United States. There is a type of rock called shale that can host a great deal of hydrocarbon. However the pore spaces are not connected, so the oil is not free to move. For this reason directional drilling has become something that is very important in the petroleum industry. This article will explain three aspects of oil recovery in shale formations

Directional Drilling

An extremely important advancement in the petroleum industry is the ability to drill horizontally. In the old days drilling was only a vertical endeavor. Drillers found that sometimes the borehole could wander in an unwanted direction. Later forward thinking engineers and petroleum geologists figured out a way to use this to their advantage. There are many tools that make directional drilling possible. This allows for the penetration horizontally of an oil or gas bearing formation. This is especially important in non-permeable formations such as shale. 

Casing

Understandably there are many people that are worried about the water aquifers. The good news is that companies are extremely careful with fresh water aquifers. When drilling, it is mandatory that casing is used to seal off the well bore from the freshwater aquifers. The casing seals the formation from contamination, but also acts as the base of the blow out preventer. 

Perforating a Formation 

You can think of rock formations as a cake that is multi layered. Of course many of these layers are hundreds of feet thick. Once a hydrocarbon rich formation is identified, it is important that as much oil or gas is recovered from that formation as possible. For this reason directional drilling is absolutely key. In shale formations the permeability is extremely low. For this purpose it is important to perforate the formation. Perforating the formation allows for hydraulic fracturing to occur. This is where permeability is created in the formation. This allows the oil or gas to be forced to the well bore, and out for production.  Contact a well driller, like Henderson Well & Pump Co., for more information.