There are many ways to fracturing the wellhead, including hydraulic fracturing, cage fracturing, packer fracturing, flow limiting fracturing, and so on, so that the fracturing tree plays a role at the wellhead. What's the difference between them?
Hydraulic fracturing is an important technical measure to increase oil and gas well production and injection well injection. It uses the ground high-pressure pumping unit. Various types of fracturing trees inject the fracturing fluid into the wellhead at a displacement that greatly exceeds the absorption capacity of the formation, causing high pressure at the bottom of the well and exceeding the formation closure stress at the well wall and the resistance of the rock. The tensile strength ruptures the formation to form a crack. Then, the liquid with proppant is continuously injected into the joint, so that the joint extends outward, and the joint is filled with proppant. After the pump is stopped, a sufficient length is formed in the formation. And sand-filled cracks of a certain width and height.
General fracturing is to put packers, sandblasting tools and other tools in the upper part of the perforating hole to fracturing the perforating part, so as to remove or reconstruct the target layer, and cooperate with different fracturing trees to operate at the wellhead.
Packer layered fracturing is realized by packer layered fracturing string, which is suitable for the transformation of high, middle, low permeability and multi reservoir with small degree of heterogeneity, small difference of water content between layers and conventional perforation.
Limited flow fracturing is to form enough borehole friction through low density perforating and large flow rate fluid supply. The fracturing tree keeps high pressure in the wellhead, so as to achieve the purpose of continuously fracturing some layers with similar fracture pressure. This technology is suitable for the completion fracturing of new wells with many layers, thin thickness, small interlayer, similar reservoir physical properties and fixed-point low-density perforation wells.