How is CNG produced?
Once a potential natural gas deposit has been located by a team of exploration geologists and geophysicists, it is up to a team of drilling experts to dig down to where the natural gas is thought to exist. Although the process of digging deep into the Earth’s crust to find deposits of natural gas that may or may not actually exist seems daunting, the industry has developed a number of innovations and techniques that both decrease the cost and increase the efficiency of drilling for natural gas. Advancements in technology have contributed greatly to the increased efficiency and success rate for drilling natural gas wells. Within the last decade new technology in horizontal drilling has enabled experts to access deeper shale plays of natural gas as well as to drill horizontally in all directions to enable one well to reach a much larger reserve of natural gas than traditional shallow wells were are able to do.
Determining whether to drill a well depends on a variety of factors, including the economic potential of the hoped-for natural gas reservoir. It costs a great deal of money for exploration and production companies to search and drill for natural gas, and there is always the inherent risk that no natural gas will be found.
The exact placement of the drill site depends on many factors, including the nature of the potential formation to be drilled, the characteristics of the subsurface geology, and the depth and size of the target deposit. After the geophysical team identifies the optimal location for a well, it is necessary for the drilling company to ensure that it completes all the necessary steps so that it can legally drill in that area. This usually involves securing permits for the drilling operations, establishment of a legal arrangement to allow the natural gas company to extract and sell the resources under a given area of land, and a design for gathering lines that will connect the well to the pipeline.
If the new well, once drilled, does in fact come in contact with natural gas deposits, it is developed to allow for the extraction of this natural gas, and is termed a ‘development’ or ‘productive’ well. At this point, with the well drilled and hydrocarbons present, the well may be completed to facilitate its production of natural gas. However, if the exploration team was incorrect in its estimation of the existence of a marketable quantity of natural gas at a wellsite, the well is termed a ‘dry well’, and production does not proceed.
Onshore and offshore drilling present unique drilling environments, requiring special techniques and equipment. The first diagram depicts both the horizontal drilling and traditional shallow drilling techniques to access the deeper shale plays and the shallow sandstone plays, respectively. The second diagram depicts various types of offshore drilling setups.