Tubing condition:

 

Oil pipeline: Oil production plant is the core sector of the oil field, each oil production plant has thousands of oil Wells, crude oil containing heavy oil, wax and other impurities, these impurities often adhere to the pipe wall to greatly reduce production efficiency, while wasting energy, regularly remove the internal and external wall of the oil pipe impurities to ensure the normal production is a major problem for each oil field equipment department to continue to solve. The conventional method is to boil in the alkali tank to remove the oil dirt adhering to the inner and outer walls of the pipe, so that the production efficiency is low and the energy consumption is large and the labor intensity is high.

 

Before the tubing is put into use, pressure test, flaw detection, straightening and repair should be carried out, so for the oil well tubing, it is necessary to first remove wax and then clean the scale, and for the heat recovery oil well pipe, only the scale needs to be cleaned. Paraffin removal requires that all the wax inside and outside the tube wall be cleaned, and the scale removal requires direct access to the inner wall of the tube and can be passed.

 

Some of the oil pipes in use are repaired and of different lengths, ranging from 10 meters to 8 meters in length, generally 10 meters in length, 74㎜ outside the oil pipe, 61㎜ inside the joint G2 1/2, the wax layer in the oil pipe is generally from 1㎜ until all the wax blocked, and the oil dirt is generally in 1~5㎜.

 

As the water injection pipe passes through the water with high hardness for a long time, the Ca2+ and Mg2+ plasma in the water is precipitated and deposited on the pipe wall, gradually forming a scale layer, which becomes thicker and thicker and even blocks the tube cavity, especially when the water after dehydration and sewage treatment at the joint station is re-injected into the formation. These waters contain a large amount of dissolved oxygen, HCO3-, H2S, dissolved salt, and even produce reducing bacteria SRB, and the reproduction of SRB will increase the content of H2S. They form many small fixed chambers between the scale and the pipe wall, which are not affected by the fluid in the pipe, and in serious cases, corrosion the metal pipe wall in a very short time. At the same time, the thicker the scale layer will cause blockage to the pipe wall. In one to two years, the scale of water with general hardness on the pipe wall can reach 5-8mm, and the higher the hardness, the worse the scale. The impurities in the groundwater of Shengli Oilfield mainly include CaCL2 and NaHCO3, with a total salinity of 15,000-200000 mg/L. Containing CL-14000-- 128000mg/L, only the second time and Jianghan Oilfield, it can be seen that timely removal of pipe wall dirt is of great significance to the operation life of equipment, the operation safety of equipment, the saving of oil field costs, and the improvement of production efficiency and the quality of oil products.

 

Working mechanism of high-pressure water: high-pressure water is reciprocated by the plunger of the plunger pump in the cylinder, controlled by several one-way valves, the water under normal pressure is instantaneously raised to a high pressure, and the high-pressure water is shot through the high-pressure pipeline by different nozzles to form different high-pressure water jets, which decompose and peel all kinds of dirt produced in the industrial production process to achieve the purpose of cleaning; High pressure water jet cleaning generally does not add chemical components, no pollution to the environment, high efficiency, low cost, is currently the preferred method of oil production pipe cleaning.

 

Several elements of high pressure water cleaning: water physical cleaning by pressure, flow, time, temperature, chemical agent, injection mode and abrasive injection and other seven elements, the functions of the elements are as follows:

 

Pressure: The stronger the dirt is, the greater the pressure requirement. The dirt on the inner wall of oil production pipe and water transmission pipe generally requires 700bar~1400bar. Through our experiment, the maximum pressure of 950bar and the operating pressure of 850bar can meet the destructive power requirements of almost all scaling pipes. The general dirt can meet the requirements with 700bar on the automatic cleaning line of the steel pipe plant in the oil field production plant, but the nominal pressure of the domestic pump is not consistent with the actual working pressure, so that the hard dirt at some oil pipe joints can not be cleaned and needs to be treated separately.

 

Flow rate: flushing capacity and strike frequency factors, the greater the flow rate, the higher the cleaning efficiency. Through our experiments and practices, under the condition of pressure 700bar, the 48L/min flow rate can ensure the simultaneous operation of the three sections of 9 jet holes and increase the rotating cleaning surface.

 

Time: The longer the time, the higher the cleaning frequency, the better the cleaning efficiency. Requires 2-3 minutes a piece, equivalent to advance and retreat each 50-70 seconds other service time 20 seconds, 10 meters long tube, advance and retreat speed of about 0.2 meters/second, 3 layers of 9 nozzles high pressure jet rotation cleaning, the speed is greater than or equal to 420rpm.

 

Temperature: Temperature can melt and disperse the structure of grease and dirt, making it loose with fluid characteristics for easy removal. Generally, 700bar water jet is sprayed to produce about 40-60 ° C, and there is no problem with cold washing, scaling and wax removal at the same time. However, under the ambient temperature of 0~15 ° C, it is very difficult to cold wash, scale and wax removal, and it is even more impossible to use cold water in the 0 ° C environment. When working below 15℃, the medium frequency heater is used to heat the tubing to 120-180 ℃, the oil scale and wax scale of the inner and outer walls of the tubing are softened, and it is easy to fall off under the blow of high pressure water jet, so the hot tubing cleaning is the best choice in the low temperature environment.

 

Chemical agent: wet loose dirt, destroy the dirt binding force. To reduce the cleaning difficulty and improve the cleaning effect, the tubing cleaning line will not involve this element.

 

Injection method: The combination of injection distance (target distance), injection Angle and number of nozzles becomes the decisive factor of maximizing cleaning ability and efficiency. This scheme adopts the multi-layer composite nozzle unique to the Robot center of Beijing Institute of Machinery Automation, with 6 spray holes at 45 ° C oblique forward Angle and 3 spray holes at 45 ° C oblique back Angle.

 

Abrasive spray: a cleaning element that increases the impact quality to strengthen the impact strength, has a strong clearing turning ability, and can replace dry sandblasting and ultra-high pressure water jet cleaning, this program is not explained.

Tubing cleaning production line introduction:

For the oil pipeline plant of oil production plant preparation group (or oil production plant maintenance team), Beijing Aolong Technology Development Limited Company in 2001 in the Gudao oil production plant of Shengli oilfield implementation of the automatic oil pipeline cleaning line schematic