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Fracturing fluid refers to a heterogeneous and unstable chemical system formed by various additives at a certain ratio. It is the working fluid used in fracturing and reconstruction of oil and gas reservoirs. Its main function is to transfer the high pressure formed by ground equipment to the formation, and make the formation fracture form a fracture and deliver supporting agent along the fracture.The fracturing fluid is widely used in Daqing, Shengli, Yanchang and other large oil fields.
The wide application of QUANSEN fracturing fluid in oilfield
Reservoir of the hydraulic fracturing process is on the ground using high pressure large displacement pump, according to the theory of fluid transmitting pressure, will have a certain viscosity of liquid (usually called the fracturing fluid), by absorbing ability is greater than the formation pressure to reservoir, and the pressure in the wellbore is increased, so as to suppress high pressure on bottom, when the pressure is greater than the wall near the ground stress and the tensile strength of the rock stratum, the cracks near the bottom hole formation:The sand-carrying fluid with proppant is continued to be injected, and the fracture extends forward and is filled with proppant. After the well is closed, the fracture closes on the proppant, thus forming the sand-carrying fracture with certain geometric size and high conductivity in the stratum near the bottom of the well, so as to achieve the purpose of increasing production and injection.The proppant is also called fracturing fluid.
【Classification and selection of fracturing fluids】
1. Fracturing fluids are divided according to their functions during construction
Fracturing fluid is a general term. In the process of fracturing, fracturing fluid in the injection well has its own function in different stages, so it can be divided into:
(1) preflush fluid: its function is to fracture the stratum and cause cracks of a certain geometric size, and it also plays a role of cooling.In order to improve its working efficiency, especially for the high permeable layer, filter loss reducing agent should be added to the front fluid, adding fine sand or powder pottery (particle size is 100~320 mesh, sand ratio is about 10%) or 5% diesel oil to plug the tiny gaps in the stratum and reduce liquid filtration.
(2) sand-carrying fluid: it plays the role of bringing the proppant (usually ceramic or quartz sand) into the crack and placing the sand in the predetermined position.This is a large proportion of the total amount of fracturing fluid.Sand-carrying fluids, like other fracturing fluids, play a role in creating fractures and cooling formations.
(3) displacement fluid: its function is to replace all the sand-carrying fluid in the wellbore into the crack.
2. Divided according to physical and chemical properties
Fracturing fluid can be divided into oil base, water base and mixed base according to its physical and chemical properties.At present, hydraulic fracturing fluid is commonly used in China
(1) Water base fracturing fluid is made by adding thickeners and additives to water as solvent or dispersing medium.Three kinds of water-soluble polymers are mainly used as thickeners, such as vegetable gels, cellulose derivatives and synthetic polymers.Synthetic polymer fracturing fluids, including polyacrylamide, partially hydrolyzed polyacrylamide, methylene polyacrylamide and their copolymers, have been widely used in oil fields due to their advantages in price and performance ratio.
(2) oil-base fracturing fluid
Oil-base fracturing fluid is suitable for low pressure and high water sensitive stratum, which takes a low proportion in fracturing operation.
【Performance of QUANSEN fracturing fluid in oilfield】
According to different design process requirements and different stages of fracturing, a kind of liquid can be used in the first construction, which contains different additives.For the preflush and sand-carrying fluids that account for the vast majority of the total fluid volume, they should have certain seam building force and make the fractured wall surface and sand-filled cracks after fracturing have sufficient flow conductivity.Then they must have the following properties:
(1) Small leakage loss.This is an important feature of long and wide seam.The filtration property of fracturing fluid mainly depends on its viscosity, the formation fluid property and the wall building property of fracturing fluid, and the filtration loss is small if the viscosity is high.Adding filtration reducing agent in fracturing fluid can improve the wall building property greatly and reduce the filtration loss.During fracturing, the comprehensive filtration coefficient of the front fluid and sand-carrying fluid is required to be no more than 1 x 10-3 m/min.
(2) Sand suspension capacity is strong.The ability of suspended sand of fracturing fluid depends mainly on its viscosity.As long as the fracturing fluid has a high viscosity, sand can be suspended in it, which is very beneficial to the distribution of sand in the joints.However, the viscosity cannot be too high. If the viscosity of fracturing fluid is too high, the height of fracture is large, which is not conducive to the generation of wide and long cracks.It is generally considered that the viscosity of fracturing fluid is 50~150mPa·s.It can be seen from the table that the liquid viscosity directly affects the settlement velocity of sand.
Sand Settling speed4.000.560.27.0.080.04
(3) Low Frictional resistance.The greater the friction resistance of the fracturing fluid in the pipe, the smaller the effective hydraulic horsepower used to make the fracture.If the friction is too high, it will greatly increase the pressure of the wellhead, reduce the construction discharge, and even cause the construction failure.
(4) Stability.Fracturing fluid stability includes thermal stability and shear stability.That is to say, the viscosity of fracturing fluid does not significantly decrease under the rising temperature and mechanical shear, which plays a key role in the success of construction.
(5) Good compatibility. The fracturing fluid will come into contact with various rocks, minerals and fluids after entering the stratum, and no physical and chemical reactions that are not conducive to oil and gas percolation, that is, it will not cause water sensitivity in the stratum and produce particle precipitation.These requirements are very important, and often the lack of effectiveness after fracturing is due to poor compatibility.
(6) Low residue.It is necessary to reduce the content of insoluble matter in fracturing fluid and the gel breaking ability before returning to discharge as far as possible, reduce the blockage of rock pores and sand filled cracks, and increase the oil and gas diversion ability.
(7) Easy to flowback. Once the fracture is closed, the faster and more thoroughly the fracturing fluid is discharged, the less damage to the hydrocarbon reservoir.
(8) Cheap price, easy to make.
【Quansen oilfield products specification】
product nameappearancemolecular weight(106）Ion degree（%）Dissolution duration （h)Solid content（%）
4000 seriesWhite particleVERYLOW/LOW/HIGH/VERY HIGHLOW/MIDIUM/HIGH≤1.0≥90
【method and attention】
1. Determine the best model and the best dosage of the product through small tests.
2. This product has hygroscopicity and should be sealed in a cool and dry place, the temperature is lower than 35 ℃.
3. Solid products should not be scattered on the ground, so as to avoid slipping after absorbing moisture.
4. When dissolving, the product should be added into the dissolver evenly and slowly, and the solidification should be avoided and mechanical shear that has been over for a long time should be avoided.
It is recommended that the mixer be 60 to 200 RPM, otherwise the polymer will hydrolyze and affect the use effect.
【 storage 】
The original product shall be kept sealed.Storage environments should be a cool, dry and ventilated, at room temperature for 10 ~ 40 ℃.Special precautions should be taken to prevent product absorption.
In accordance with the specified storage conditions, the original packaging products can be stable for at least 12 months.
【 packing 】
25kg composite paper bag /750kg pallet OR customer demand.China Oilfield Auxiliary manufacturers