Hydraulic fracturing by Chesapeake
Hydraulic fracturing is the process of creating more and easier pathways for the hydrocarbon to flow into the production tubing by hydraulically fracture the formation rock. In order to maximize the production potential of the well, the shale formation will be hydraulically fractured.
In preparation for the fracturing process, the casing will be perforated in the horizontal portion of the well using tubing conveyed perforating guns containing explosive charges.
The perforated intervals are space to approximately 50 to 80 feet apart and created connection between the production casing and the shale formation.
With the initial perforation complete, the tubing and perforating guns are pulled to the surface and the work over rig is replace by a hydraulic fracturing crew, consisting of a number of high pressure pumps and blending equipment. This equipment will pump a mixture of water and proppant usually send through the new and creating perforations in the production casing and into the shale formation.
First, water is passed from water storage impoundment into the blue working tanks defected in this location. The water is then fold into a hydration unit which provides the ability to gel the fluid before this transfer to the blender.
At the blender, proppant and a the small amount of chemicals that aid in the fracturing process are added. The blender transfers the fluid and proppant mixture to the pump trucks through the low pressure side of the manifold.
Pump and fracture
The fracturing pumps increase the pressure of the fluid, sending it back through the high pressure side of the manifold to the fracturing where it enters the well. The entire fracturing process is controlled from the treatment monitoring van. When the fracturing fluid reaches the perforations, pressure builds into the shale formation fractures, allowing fluid to enter into the formation. Additional fractures are created along natural zones of weakness in the shale. These fractures are contained within the shale formation well below the ground. After the initial stage of fluid, called the pad, is pumped to create a fracture area. Proppant is added into the fluid and this distributed throughout the newly created fracture network. At the conclusion of the fracturing treatment the proppant allows the fractures to remain open so that the natural gas can flow into the production casing into the surface. These complete the first of several stages in the fracturing process.
Repetition to complete all the fracturing stages
This process is repeated by lowering and pumping down an isolation plug and perforating guns into the well board to complete the next stage of fracturing. This time, the tools are conveyed into the well by a wireline unit which allows the fracturing process to perceive much faster and more efficiently. A lubricator is used to control the pressure of the well. well the operation is taking place. On the bottom of the perforating gun, a composite bridge plug is place to isolate the newly fractured zone. This ensures that the subsequent fracturing treatment is contain in the current zone. The perforating gun is again fired at roughly 50 to 80 foot intervals creating a connection between the production casings in the shale formation. The fracturing process is then repeated until all of the stages are completed. A typical shale well has approximately 8 to 12 stages of fracturing.
At the conclusion of the fracturing operations, the isolations plugs are removed from the well and production can start. The produced fluids are diverted to a flow back manifold into storage tanks. The fluids are then recycled or disposed off according to state and federal regulations.