Provides a means of hydraulic fracturing fluid fracturing operations , but in the factors affecting the success of the fracturing , fracturing fluid and its performance is extremely important. For large-scale fracturing , this factor is even more prominent. The purpose of the Hydraulic Fracturing Proppants fluid has two aspects : one is to provide sufficient viscosity so as to extend the use of hydraulic fractures wedge role in the formation and cracks along the transportation and laying of proppant ; After the addition is completed fracturing , fracturing rapid chemical decomposition of broken plastic liquid to a low viscosity , to ensure the majority of the fracturing fluid is discharged back to the ground in order to purify the cracks.
Fracturing fluid is a general term , the resin coated silica sand process, the fracturing fluid injection wells have their effect at different stages , it can be divided into:
( 1 ) Pre- solution: its role is to rupture and cause cracks in the formation of a certain geometry , but also play a role in cooling . In order to improve its efficiency , especially for high- permeability layer , pre- liquid fluid loss additive to be added , add sand or ceramic powder (particle size of 100 to 320 mesh , sand ratio of about 10% ) or 5% of diesel , plug formation of tiny cracks and reduce liquid filtration .
( 2 ) sand-carrying fluid: it acts as a proppant ( typically ceramic or quartz sand ) on the sand into the fracture and the effect on the predetermined position . The total amount of fracturing fluid , the proportion of which accounts for a large part . Carrying sand fracturing fluid and other fluid , like sewing and cooling has made the role of the formation .
( 3 ) the replacement fluid: its role is to bring sand in the wellbore fluid into the cracks for all .
Depending on the different stages of the design requirements and the fracturing process , the fracturing fluid may be used in a construction of a liquid containing various additives . For the vast majority of the total amount of liquid fluid and sand carrying fluid front , should have a certain force and to create cracks in the wall joints and cracks after fracturing sand filling has sufficient conductivity . So they must have the following properties:
① filtration small . This is made long slit , slit width important performance . Fracturing fluid filtration , primarily depends on its viscosity, formation fluid properties with walls made of fracturing fluids , high viscosity fluid loss is small . Add in the fracturing fluid fluid loss agent can greatly improve build walls to reduce fluid loss . When fracturing , requiring pre- liquid , liquid integrated carrying sand filtration coefficient ≤ 1 × 10-3m/min1/2.
② suspended sand ability. The ability of suspended sand fracturing fluid mainly depends on its viscosity. As long as the fracturing fluid has a higher viscosity, in which the sand can be suspended , in which the distribution of sand seam is very advantageous. However, the viscosity is not too high , if the viscosity of the fracturing fluid is too high, the height of large cracks , is not conducive to produce a wide and long cracks. The viscosity of the fracturing fluid is generally considered as 50 ~ 150mPa · s suitable. Table 3-1 visible liquid viscosity directly affects the size of sand settling velocity .
( 1 ) Pre- solution: its role is to rupture and cause cracks in the formation of a certain geometry , but also play a role in cooling . In order to improve its efficiency , especially for high- permeability layer , pre- liquid fluid loss additive to be added , add sand or ceramic powder (particle size of 100 to 320 mesh , sand ratio of about 10% ) or 5% of diesel , plug formation of tiny cracks and reduce liquid filtration .
( 3 ) the replacement fluid: its role is to bring sand in the wellbore fluid into the cracks for all .
Depending on the different stages of the design requirements and the fracturing process , the fracturing fluid may be used in a construction of a liquid containing various additives . For the vast majority of the total amount of liquid fluid and sand carrying fluid front , should have a certain force and to create cracks in the wall joints and cracks after fracturing sand filling has sufficient conductivity . So they must have the following properties:
① filtration small . This is made long slit , slit width important performance . Fracturing fluid filtration , primarily depends on its viscosity, formation fluid properties with walls made of fracturing fluids , high viscosity fluid loss is small . Add in the fracturing fluid fluid loss agent can greatly improve build walls to reduce fluid loss . When fracturing , requiring pre- liquid , liquid integrated carrying sand filtration coefficient ≤ 1 × 10-3m/min1/2.
② suspended sand ability. The ability of suspended sand fracturing fluid mainly depends on its viscosity. As long as the fracturing fluid has a higher viscosity, in which the sand can be suspended , in which the distribution of sand seam is very advantageous. However, the viscosity is not too high , if the viscosity of the fracturing fluid is too high, the height of large cracks , is not conducive to produce a wide and long cracks. The viscosity of the fracturing fluid is generally considered as 50 ~ 150mPa · s suitable. Table 3-1 visible liquid viscosity directly affects the size of sand settling velocity .
