SDKX--5000WY series composite fiber temporary plugging agent technical manual
1. SDKX--5000WY temporary plugging agent
In order to enable oil wells to be mined for many years, new acidification fracturing and new technologies and new products are adopted and recovery rates are improved. In order to make the crude oil originally enclosed in the reservoir appear as a radiation channel, by adding a multi-stage SDKX--5000WY temporary plugging agent function, temporarily blocking and turning to form a new mesh oil outlet path. The method commonly used at home and abroad is the fracturing steering method. In order to achieve sufficient pressure, it is necessary to use a fiber composite temporary plugging agent to temporarily block the original gaps, cracks, and oil passages. After applying pressure with water pressure, new gaps, cracks and oil passages are formed. This requires that The plugging agent must not only have a considerable pressure-resistant support capacity but also have the ability to be dismantled. However, it is difficult to remove the plugging agent by manual and mechanical means several thousand meters underground. Therefore, this plugging agent must be a special fiber temporary plugging agent that is water-soluble or oil-soluble. Due to the great differences in the geological structure of oil wells in various regions, some regions use oil-soluble temporary plugging agents (such as Changqing Oilfield, Qinghai Oilfield, Xinjiang Karamay Oilfield, foreign Middle East, etc.), while others can only use water-soluble temporary plugging agents (such as Daqing Oilfield, North my country Oilfield, etc.).
At present, temporary plugging agent manufacturing companies divide temporary plugging agents into two categories: water-soluble temporary plugging agents and oil-soluble temporary plugging agents. Our company can produce all series of temporary plugging agents from water-soluble to oil-soluble "SDKX--5000WY series fracturing temporary plugging agents".
Its structural characteristics are: there are two materials with alternating multi-layer stacks in the temporary plugging agent material, one is a water-soluble layer (material layer A) and the other is an oil-soluble layer (material layer B). The two materials alternately stack multiple layers to form temporary plugging agent particles. Figure 1. A microscopic diagram of alternating multi-layer stacking of medium temporary plugging agents.

Figure 1. Microscopic diagram of alternating multi-layer stacking of temporary plugging agents
Note: In the figure, AB-AB... are alternately stacked.
Spherical temporary plugging agent particles were obtained through hot pressing of the molding equipment. Figure 2. The left picture is a photo of the SDKX--5000XY temporary plugging agent particles. Figure 2. The right picture is a photo of the product packaged and factory-exited.

Figure 2. Photos of SDKX--5000XY type temporary plugging agent granule products and packaging products from factory
Its application characteristics are:
1. In the northwest and other regions, according to the user's requirements, we produce oil-soluble temporary plugging agent, and the main products are SDKX--5000Y-O type fracturing temporary plugging agent;
2. In the northeast and other regions, we produce water-soluble temporary plugging agent, and the main products are SDKX--5000Y-W type fracturing temporary plugging agent.
Its main performance characteristics are:
1. Oil-soluble temporary plugging agent, the main product is SDKX--5000Y-O type oil-soluble temporary plugging agent, which can be dissolved in crude oil at 50-160℃ (the specific temperature range is set according to the oil well temperature), the dissolution time is 60-180 minutes, the compressive strength: above 45Mpa;
2. Water-soluble temporary plugging agent, the main product is SDKX--5000Y-W type water-soluble temporary plugging agent, which can be dissolved 90-95% in water at 50-160℃ (the specific temperature range is set according to the oil well temperature), the dissolution time is 60-180 minutes, and the remaining 5-10% of the remaining B-layer material floats on the water surface and does not block the equipment. If there is an oil layer on the water, the emulsion residue will be completely dissolved, and the compressive strength: above 45Mpa.
3. The outstanding advantages are: because of the existence of a laminated structure, it not only has high compressive strength above 45Mpa in the dry solid state at normal temperature and pressure, but also maintains high compressive strength in the oil well reservoir; this is a general temporary plugging agent that is difficult for general temporary plugging agents to achieve, especially water-soluble temporary plugging agents. Although it has high strength under the dry solid state at normal temperature and pressure, at critical moments when pressure resistance is really needed in the oil well reservoirs, they will become soft in water above 45°C, lose compressive performance, and lose temporary plugging steering agent capabilities.
1.2 Introduction and classification of SDKX--5000XY type fracturing temporary plugging agent
1.2.1 Introduction to SDKX--5000XY type fracturing temporary plugging agent
SDKX--5000XY type series fracturing temporary plugging agent is a standardized high-tech product developed successfully based on the oil field geological conditions in northwest China, Qinghai and Daqing areas, in conjunction with the research and development teams of petroleum majors and materials majors of two famous geological and petroleum universities in China and the research and development teams of petroleum majors and materials majors in provincial key laboratories. It relies on professional molding and processing units for standardized production and inspection. It can adjust the components and processing methods according to the conditions of the oil well to meet the performance requirements of users:
1. It can adjust the ratio and crosslinking agent of the AB layer to meet the water-soluble or oil-soluble choice of temporary plugging agent. When the AB layer ratio is listed in the range of 1:1-1:8, it belongs to the oil-soluble temporary plugging agent, namely SDKX--5000Y-O type fracturing temporary plugging agent; when the AB layer ratio is listed in the range of 9:1-9.5:1, the temporary plugging agent belongs to the water-soluble temporary plugging agent, namely SDKX--5000Y-W type fracturing temporary plugging agent.
2. The dissolution temperature can be adjusted through component ratio and crosslinking dose to meet the needs of temporary plugging agents for various temperature conditions.
3. The compressive strength can be adjusted through component ratio and processing technology to meet the compressive strength needs of temporary plugging agents.
1.2.2 SDKX---5000XY type fracturing temporary plugging agent soluble principle
1.2.2.1 Oil-soluble SDKX--5000XY-O type temporary plugging agent soluble principle
Adjust the ratio and crosslinking agent dosage of AB layer. When the ratio of AB layer is in the range of 1:1-1:8, it belongs to the oil-soluble temporary plugging agent, namely SDKX--5000XY-O type fracturing temporary plugging agent. It is insoluble in pure water at room temperature and oil well temperature, and dissolves in a mixture of water, oil and water (emulsion) or oil with oil stored there.
According to the construction process of fracturing temporary blockage, the conditions for the oil well construction process are as follows: (1) Water and oil coexist; (2) The temporary blockage agent will withstand a pressure of several tens of megapas; (3) The water pressure is applied due to the gap type, which is equivalent to playing a stirring role. According to such conditions, we designed the temporary plugging agent as a microstructure: alternately stacked microstructures.
Alternating laminated microstructure means: the temporary plugging agent includes two parts of the material, one is an oil-soluble layer (layer A), and the other is a water-soluble layer (layer B), which belongs to AB-AB-AB... The layered alternating coating structure, the micromorphology is similar to the "onion structure", and the thickness of each alternating layer is micron-scale. During the construction process, this temporary blocking agent is not dissolved in a single water. It can only be dissolved when the oil is present and the temperature of the oil reaches the corresponding temporary blocking agent application temperature. When layer A is dissolved by oil, layer B can be dissolved by water, peeled off and dissolved alternately, softened at a certain temperature (the temperature range is determined by the product model), and after softening, it will be dissolved in 60-180 minutes.
1.2.2.2 Water-soluble SDKX---5000XY-W type temporary plugging agent soluble principle
Adjust the ratio and crosslinking agent of the AB layer. When the ratio of AB layer is 9:1-9.5:1, it belongs to a water-soluble temporary plugging agent, namely SDKX--5000XY-W type fracturing temporary plugging agent. It is insoluble in water at a normal temperature. At a certain temperature in the underground well, the 90-95% of the A-layer water-soluble material contained in it will first swell and expand the distance between the layers and then dissolve in water at 50-180℃ (the specific temperature range is set according to the temperature of the oil well). The dissolution time is 60-180 minutes. The remaining 5-10% of the remaining B-layer material will float on the water surface and be in an emulsion state without blocking the equipment. If there is an oil layer on the water, the emulsion residue will be completely dissolved.
1.2.2.3 Principle of adjusting strength by alternating layered microstructures
Generally, water-soluble temporary plugging agents have a strong surface strength, but before fracturing, they will become softer in water above 45°C, lose compressive performance, and lose temporary plugging ability. This is a common disadvantage of water-soluble temporary plugging agents made of bone glue, gelatin, soluble starch and low-temperature paraffin, and the price is also very high.
In addition to the water-soluble A-layer material, the alternating laminated microstructure also contains the B-layer material that serves as the final strength support. The alternating lamination microstructure forms a "arch" support to ensure the final strength of the temporary plugging agent during use, so as to complete the fracturing process. The compressive strength of the temporary plugging agent is adjusted and controlled in the manufacturing process by adjusting and controlling the amount of B-layer material, crosslinking agent and processing conditions.
1.2.2.4 The principle of dissolution temperature-time control of temporary plugging agent
(1) The main components of SDKX--5000XY type fracturing temporary plugging agent are: 17%-53% sodium oxalate, 17%-53% ammonium chloride, 25%-29% phenolic resin, 1%-5% hexadecimal methyltetramine.
(2) The role of each component: phenolic resin is the main source of strength; hexylmethyltetramine is the molding and curing agent in the production process; sodium oxalate and ammonium chloride are fusion agents and dense agents, which play the effect of making the temporary plugging agent complete and strengthening strength in the production process; phenolic resin and hexylmethyltetramine form the B layer (oil-soluble layer) of the material at the manufacturing temperature; sodium oxalate and ammonium chloride and partially permeated phenolic resin form the A layer of the material (can be completely dissolved by water).
The control of the dissolution temperature and dissolution time of the temporary plugging agent is mainly adjusted by the amount of hexyl tetramine in the component. In the range of 50℃-130℃, generally with the increase of hexyl tetramine in the phenolic resin, the dissolution temperature of the temporary plugging agent will increase. Conversely, as the hexyl tetramine decreases, the oil solution temperature decreases.
The study found that when the presence of sodium oxalate and ammonium chloride, the dissolution temperature of the temporary methyltetramine in the crude oil containing moisture is about 50℃ and completely dissolved in 1.5-3 hours. For every 0.5% increase of hexamethyltetramine, the dissolution temperature of the temporary methyltetramine increases by about 10℃. The relationship between the dissolution temperature of the temporary methyltetramine and the dosage of hexamethyltetramine is shown in Table 01.
Table 01 Relationship between dissolution temperature and dissolution time and the dosage of hexadecimal methyltetramine

Special notes:
1. The dissolution temperature is also related to the dissolution time. When the temperature is lower than the calculated value, it can be dissolved for a long time. For example, the TPA80 type fracturing temporary plugging agent theoretically needs 80℃ to dissolve, but in fact it can also be dissolved at 55-60℃, but the dissolution time is relatively long, generally 2 hours.
2. For temporary plugging agents that are resistant to 180℃, the situation is quite special. They are mainly used for the plugging of pipe orifices in natural gas fields. In principle, their temperature control is more complicated. In addition to the dosage of hexadecimal methyltetramine, they are also related to the amount of phenolic resin and other components. When using gas fields, oil is used to deblock before deblocking is used. The principle will not be explained in detail here.
(3) Relationship between curing reaction and dissolution temperature:
Equation of the phenolic resin synthesis reaction:

The phenolic resin and hexadecimal methyltetramine curing reaction at a certain temperature to form a three-dimensional web structure material. This solid material has a high strength (more than 100 MPa), but is brittle. After adding other components raw materials, it is improved to become a temporary plugging agent material with sufficient strength and toughness. When the added curing agent hexadecimal methyltetramine content is sufficient, it can cure quickly, but it is inhibited when sodium oxalate and ammonium chloride exist. The curing reaction does not all form a three-dimensional web structure, because adjusting the amount of hexadecimal methyltetramine can control the proportion of the three-dimensional web structure, so adjusting the dissolution temperature is actually adjusting the amount of hexadecimal methyltetramine. The higher the hexadecimal methyltetramine content, the more the three-dimensional web structure, the higher the three-dimensional web structure needs to be disassembled, and vice versa.
1.2.3 Classification of SDKX--5000XY type fracturing temporary plugging agent
As mentioned earlier, our temporary plugging agents are divided into two categories: oil-soluble SDKX--5000XY-O series and water-soluble SDKX--5000Y-W series. Under these two major tree systems, they are divided into subdivided types of different temperatures according to the dissolution temperature.
1.2.3.1 Oil-soluble temporary plugging agent SDKX--5000XY type fracturing temporary plugging agent series product classification, type selection is made according to the different temperatures of the oil well:
(1) SDKX--5000XY type fracturing temporary plugging agent:
suitable for oil wells with oil wells with oil wells temperature of 50℃-65℃ (shallow oil wells);
(2) SDKX--5000XY-O2 type fracturing temporary plugging agent:
suitable for oil wells with oil wells with oil wells temperature of 60℃-80℃; (deep oil wells)
(3) SDKX--5000XY type fracturing temporary plugging agent:
suitable for oil wells with oil wells with oil wells temperature of 80℃-180℃. (Deep oil well and gas field pipe joint)
SDKX--5000XY type pressure temporary plugging agent can be dissolved in the mixed liquid of oil and water within the corresponding temperature range after construction. The temperature underground of the oil well is generally 60-120℃. It can automatically remove the blocking agent and completely dissolve and remove the temporary plugging agent in the oil field temperature range. The original gaps and cracks are temporarily sealed, and new cracks are fractured in a different direction than the original crack.
1.2.3.2 Water-soluble temporary plugging agent SDKX--5000XY type fracturing temporary plugging agent A series of product categories, and types are selected according to the temperature of the oil well:
(1) SDKX--5000XY fracturing temporary plugging agent:
suitable for oil wells with oil well temperatures of 50-65℃ (shallow oil well);
(2) SDKX--5000XY type fracturing temporary plugging agent:
suitable for oil wells with oil well temperatures of 60-80℃; (deep oil wells)
(3) SDKX--5000XY type fracturing temporary plugging agent:
suitable for oil wells with oil well temperatures of 80-180℃. (Deep oil wells and gas field pipe joints)
After construction, the SDKX--5000XY type pressure temporary plugging agent can be dissolved in water within the corresponding temperature range. The temperature underground of the oil well is generally 60-160℃. It can automatically remove the plugging agent and completely dissolve and remove the temporary plugging agent in the oil field temperature range. The original gaps and cracks are temporarily sealed, and new cracks are fractured in a different direction than the original crack.

1. Product technical parameters:

(1) Softening temperature range of SDKX--5000XY type fracturing temporary plugging agent: 50-80℃
Due to the fundamental difference in structure and working principle with traditional oil-soluble temporary plugging agent, SDKX--5000XY type fracturing temporary plugging agent adopts alternating stacking structure and dissolution method, there is no fixed "softening point" and only one softening temperature range.
(2) Compressive strength: 45-90 Mpa (compressive strength order: TPA50 type < TPA 80 type < TPA 130 type).
 (3) Dissolution rate (crude oil or water): 85%~100%
(4) Temporary plugging rate: 95%~100%
(5) Permeability recovery rate: 96%~100%
(6) Graphic: spherical, fiber type.
(7) Particle size: 1.5 -5.5mm, average particle size 1.33mm.
(8) Particle density: 1.12-1.46g/cm3.
3. Operating procedures for product quality testing
SDKX--5000XY type fracturing temporary plugging agent is fundamentally different from the traditional fracturing temporary plugging agent in terms of structure and principle. It has been gradually promoted in the northwest and northeastern regions. The user's reaction is satisfactory in terms of pressure and fracturing production increase success rate. In order to facilitate users to have a substantial understanding of the product before using it, the operating procedures for testing the product are described based on the particularity of the product's microstructure.

3.1. The operating procedures of oil-soluble temporary plugging agent SDKX--5000XY are as follows:
Equipment: (1) Constant temperature water bath pot (Figure 1.); (2) Agitator: Laboratory electric agitator (Figure 2.): (3) Thermometer: 0-200℃
Specific regulations:
(1) Heat the water bath to the temperature to be tested for constant temperature;
(2) Take a 1000 ml beaker, add 500 ml kerosene (crude oil is more realistic) and 50-100 ml water (oil-water ratio 10:1 to 5:1). The reason is: oil and water exist at the same time during the actual working hours;
(3) Insert the stirrer into the beaker, slowly turn the stirrer, and it can be rotated, and simulate the turbulent state of the oil field;
(4) Fix the thermometer in the beaker kerosene (or crude oil)-water mixture, and use the display temperature of the thermometer as the real temperature (temperature control temperature is only for reference, inaccurate);
(5) Take 1-5 grams of temporary plugging agent, add the kerosene-water mixture in the beaker, and start the timing at the set temperature.
Note: 1. Stirring is very important because oil is lighter than water. If you do not stir, the temporary plugging agent can only contact the water and cannot touch kerosene (losing the effect of oil dissolution), and stirring imitates the actual turbulent state; 2. The temperature must be constant because the underground temperature is constant. 3. There should not be too much temporary plugging agent, because the amount of oil-water flows in the hole is large, while the amount of laboratory oil-water is quantitative.
The experimental results should be:
(1) SDKX--5000XY; Type 50 pressure temporary plugging agent: softened in the range of 50-65℃ and dissolved in 1.5 hours, and finally added 100 water to dissolve completely transparently at the corresponding temperature;
(2) SDKX--5000XY; Type 80 fracturing temporary plugging agent: softened in the range of 60-80℃ and dissolved in 1-1.5 hours, and finally added 100 water to dissolve completely transparently at the corresponding temperature;
(3) SDKX--5000XY; Type 130 fracturing temporary plugging agent: softened in the range of 80-130℃ and dissolve completely transparently at the corresponding temperature. 
3.2. The test operating procedures of water-soluble temporary plugging agent SDKX--5000XY are as follows:
(1) Heat the water bath to the temperature to be tested for constant temperature;
(2) Take a 1000 ml beaker and add 500 ml of water;
(3) Insert the stirrer into the beaker, slowly turn the stirrer, and it can be rotated to simulate the turbulent state of the oil field;
(4) Fix the thermometer in the beaker water, and use the display temperature of the thermometer as the real temperature (the temperature control temperature is only for reference, inaccurate);
(5) Take 1-5 grams of temporary plugging agent, add it to the beaker water, and start the timing at the set temperature.
Note: 1. Stirring is very important. Stirring imitates the actual turbulent state; 2. It must be constant because the downhole temperature is constant. 3. There should not be too much temporary plugging agent, because the amount of oil-water flows in the hole is large, while the laboratory water is quantitative.
The experimental results should be:
(1) SDKX--5000XY; Type 50 fracturing temporary plugging agent:
suitable for oil wells with oil wells with temperatures of 50℃-65℃ (shallow oil wells);
(2) SDKX--5000XY; Type 80-O fracturing temporary plugging agent:
suitable for oil wells with temperatures of 60℃-80℃; (deep oil wells)
(3SDKX--5000XY; Type 130 pressing temporary plugging agent: soften the range of 80-130℃ ＼0-1.0 hours to dissolve. 
4. Construction methods and precautions: This temporary plugging agent has high strength, and the dosage is appropriately reduced according to the construction conditions for the first time to avoid excessive pressure explosion of the pipe.
(1) The sand mixer is directly added on site, and the addition method is simple. Adding speed requirements: 25Kg/10s.
(2) The SDKX--5000XY-2 series of temporary plugging agent has a high sealing strength. The on-site construction adds volume according to the perforation thickness (80Kg-120Kg)/M, which can basically achieve the effect of effective sealing and temporary plugging of old joints.
(3) This product is non-toxic and odorless, and can be directly contacted by hand and needs to be stored in a dry and ventilated place.
(4) Packaging and storage;
adopt three-in-one packaging, four-in-one packaging, with a net weight of 25kg;
storage should be stored in ventilation and light, with a temperature of 5-35℃. Valid for 2 years.