This page contains a Flash digital edition of a book.
GATHERING SYSTEMS


E&P production is found “upstream”, such as wells and gathering lines, while others are “downstream” like compressor stations and city gates. In all cases the journey of natural gas starts in the ground at the well and ends with the end user.


GATHERING SYSTEMS


Wells Natural gas is found deep within the earth. It is located and brought to the surface by companies that are involved in a two- step process of exploration and production (E&P): exploration for the natural gas and production by drilling and operation of the wells to mine natural gas. These wells can be on shore or off shore. In some wells the gas pressure is enough to force product to the surface and initially move it to the gathering lines. When the pressure is low, pressurized water can be used to force the natural gas out of the ground into gathering lines.


Gathering Lines


The natural gas that the well produces is gathered from many wells in low pressure pipelines referred to as gathering lines. These pipelines, in turn, link wells and production areas to cen- tral collection points and then converge to make larger lines downstream to a storage site or the gas processing plant.


PROCESSING PLANTS


Natural gas taken directly from the earth has impurities that must be removed before it can be transported to the end user. These impurities including hydrocarbons, liquids, hydrogen sulfide (H2S) and water are removed in the processing plant. Sulfur and carbon dioxide must also be removed from natural gas. Sulfur can damage the pipes and has a rotten egg smell, but is valuable. In fact, the sulfur extracted from the natural gas makes up 15% of the USA’s sulfur production.


Often the natural gas is part of a mixture containing petro-


leum liquids. Removal of impurities allows for better transport and end usage of the gas. Treatment facilities contain equip- ment specifically designed to remove these impurities. One unique impurity is called Natural Gas Liquids (NGL) which are valuable commodities that are sold on the open market. Once impurities have been removed or brought to an accept- able regulated level the natural gas is considered “pipeline quality,” sometimes referred to as dry gas. However, the gas is now completely odorless in transmission. Depending on the


FIGURE 3.3 Gathering lines. Courtesy of Bill Hand


FIGURE 3.2 Well head. Courtesy of PHMSA


FIGURE 3.4 Processing plant.


37

Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36