CN1995269A

CN1995269A - Chemical formula and process for removing organic block adjacent to oil well area

Info

Publication number: CN1995269A
Application number: CN 200610134983
Authority: CN
Inventors: 尹恕; 卢德平; 杨雄; 吴秀军; 钦焕光; 王洪胜
Original assignee: Liaohe Petroleum Exploration Bureau
Current assignee: Liaohe Petroleum Exploration Bureau
Priority date: 2006-12-18
Filing date: 2006-12-18
Publication date: 2007-07-11

Abstract

The invention discloses a chemical formula technique to eliminate the organic block near oil well, which comprises the following parts: main agent, catalyst A, controlling agent B and delay agent C, wherein the main agent, ammonium chloride and controlling agent B sodium sulfate are blended together to form the first component, which is mixed the catalyst octanoic acid A and delay agent petrol C, which forms the second component; two components are put in the tank according to proportion, which can generate large amount of heat and nitrogen with organics; the material can increase bottom pressure, which cleans peripheral material of well wall.

Description

Chemical formula process for removing organic matter blockage in near-well zone of oil well

The technical field is as follows:

the invention relates to an oil well blockage removing process, in particular to a chemical formula process for removing organic matter blockage in a near-well zone of an oil well.

Background art:

in the production process of oil and gas fields, because the temperature of the stratum or the environment is low, some adverse factors are often brought to the production, for example, the paraffin precipitation of the stratum and a shaft, the cold damage of hydraulic fracturing to the stratum and the like can cause the paraffin precipitation of the stratum around the shaft, the permeability of the stratum is reduced, the production difficulty is increased, and the cost is increased. At present, a plurality of heating methods are tried on site to solve the problems, such as steam injection for thick oil extraction, hot water circulation paraffin removal, electric heating blockage removal and the like. These methods have limited their application due to complex processes, high cost, etc., and have been gradually replaced by some in situ chemical heat generating systems. The chemical heat generating system heats the near-wellbore area by using chemical heat generated by reaction of one or more water-soluble medicaments, thereby achieving the purpose of removing blockage and paraffin. Three chemical heat generating systems commonly used at present are: (1) a nitrite and ammonium chloride heat generating system, (2) a hydrogen peroxide heat generating system, and (3) a chromic anhydride-polyhydroxy aldehyde oxidizing heat generating system. Wherein, the hydrogen peroxide heat generation system and the chromic anhydride-polyhydroxy aldehyde oxidation heat generation system have the advantages of less heat generation, poor safety, high price and less use; sodium nitrate and ammonium chloride are cheap and easily available common chemical reagents, and react under the acid catalysis condition to generate a large amount of heat and gas, and the application is more as follows:

in actual production construction, sodium nitrite and sodium chloride react, and the reaction is only generated by using acid with higher than moderate strength. The catalyst used at present is mainly hydrochloric acid, oxalic acid and the like. After being mixed with a reaction system according to a certain weight ratio, the catalysts generally quickly cause reaction, and although the expected purpose can be achieved, the chemical reaction condition can be carried out in the construction process, so that a great potential safety hazard is left.

The invention content is as follows:

the invention aims to overcome the defects and provides a chemical formula process for removing organic blocking of an oil well near a well zone,

the technical scheme is as follows:

the invention adopts the following process steps: the formula comprises four parts of a main agent, a catalyst A, a control agent B and a time delay agent C, wherein the main agent is ammonium chloride or sodium nitrite and water; the catalyst n-octanoic acid A is an organic matter which can be slowly hydrolyzed to generate strong acid, and the chemical formula of the catalyst is R-H; the control agent is sodium sulfate B which is weak base and has a chemical formula of R-OH; the time-delay agent gasoline C is an organic solvent, when in preparation, the main agent water, the ammonium chloride and the control agent B sodium sulfate are dissolved together and stirred uniformly to form a first component, then the catalyst n-octanoic acid A and the time-delay agent gasoline C are mixed and dissolved together to form a second component, the two components are placed in a tank body according to a certain proportion, when in construction, the PH value of the mixed solution is adjusted to be more than 5, and then the solution is squeezed into a shaft by a cement truck.

Compared with the prior art, the invention has the remarkable characteristics that:

the invention adopts the solution composed of the main agent of ammonium chloride, water, the catalyst of n-octanoic acid, the control agent of sodium carbonate and the time delay agent of gasoline, which have good intersolubility with each other, and can generate strong acid organic matters to be used to generate large amount of heat and nitrogen under the oil well, the heat energy of the solution can effectively melt the organic matters near the oil well, and the nitrogen after the reaction can play a role in increasing the bottom pressure, thereby playing a role in carrying and melting the organic matters near the oil well to discharge.

When the invention is used, the reaction system can be controlled to react at a proper time according to requirements, so that the reaction efficiency is higher and the safety standard is higher.

The specific implementation mode is as follows:

the invention is given by the following examples, which are further described below.

Example 1:

the process formula comprises: the mixed solution ofmain agent water, ammonium chloride and control agent sodium carbonate is uniformly stirred to form a first component, the catalyst n-octanoic acid and the time delay agent gasoline are mixed together to form a second component, then the two component solutions are placed into a tank and mixed to form the water-soluble polymer composite material, and during construction, the water-soluble polymer composite material is squeezed into a wellhead 2 by a cement pump truck 4.

Example 2:

the dosage of the main agent water is 50%, the sodium nitrite is 20.70%, and the dosage of the control agent: sodium carbonate: 2.37%, NH4 Cl: 16.05, catalyst: n-octanoic acid: 4.55 percent; time delay agent: 6.33% of gasoline, the volume of the blocking remover prepared according to the dosage is 30 square, the total weight is 35 tons, the solvent is used for carrying out chemical blocking removal construction on a certain well of the Liaohe oil field at 1608.1-1677.0 meters of a construction well section, the crude oil in the well contains 28.5% of colloid asphaltene, 36.3% of wax weight and 47 ℃ of ground temperature during construction, the construction operation time is 90 minutes, the pressure of a construction injection well head is gradually increased to 18.5MPa from 12MPa, and the pressure is released for 80 minutes after the well is closed and the reaction is carried out for 3 hours after the construction is finished.

The method has the following effects: 2.2 tons of daily produced liquid before construction, 1.4 tons of daily oil production, 4.7 tons of average daily produced liquid after construction, 3 tons of average daily oil production and 114 percent of oil increase rate.

Example 3:

during construction, different main agent concentrations are prepared according to the underground plugging removal heat, and becauseammonium chloride and sodium nitrite can absorb a large amount of heat when being dissolved in water, hot water is used for preparation. The control agent B is weak base which can be dissolved in the catalyst or the main agent, the chemical formula is R-OH, sodium carbonate is selected as the control agent, the concentration of the control agent is required to be lower than that of the strong acid hydrolyzed by the catalyst A and the n-octanoic acid, and when the construction is finished, the well is opened and the open flow is required to be carried out in time so as to be beneficial to discharging the blocking object.

Example 4: the chemical reaction principle of the invention is as follows:

(1) after the catalyst n-octanoic acid is mixed with water in the main agent, the n-octanoic acid is slowly hydrolyzed to generate strong acid, and the reaction formula is as follows:

C₇H₁₅COOH→C₇H₁₅COO^-(n-octanoate) + H⁺(acid)

(2) And the generated acid reacts with a control agent sodium carbonate to keep the pH value of the solution in a state of more than 5:

Na₂CO₃→2Na⁺+CO₃ ^2-，CO₃ ^2-+H⁺→HCO₃ ^-

(3) when the sodium carbonate reaction of the control agent is finished, H in the solution⁺The concentration is increased, and the acidity is enhanced;

(4) when the pH value is less than 3, the ammonium chloride and the sodium nitrite are initiated to start reaction

(5) The ammonium chloride reacts with the sodium nitrite to generate a large amount of heat and gas, the heat melts solidified organic matters in the near wellbore zone, and the gas can increase the formation pressure;

(6) and when the well is opened and the blowout is performed, the gas generated by the reaction carries the melted stratum blockage to return to the ground. The near wellbore zone organic plug is released.

After the ammonium chloride and the nitrous acid are dissolved in water, ammonium ions and nitrite ions are generated through hydrolysis. If the pH of the solution is less than 3, the two ions react violently to generate a large amount of gas and heat; when the pH is more than 3 and less than 5, slowly reacting; when the pH is>5, no reaction is observed.

During on-site construction, if violent reaction occurs in a well, a large amount of gas and heat can be generated, and high temperature and high pressure phenomena occur, so that safety accidents are caused. Therefore, the chemical reaction must be allowed to proceed after the construction preparation is completed.

After the main agent is prepared, the solution is in alkalescence due to hydrolysis of sodium carbonate, the pH is about 9, and the main agent does not react. In the application, the n-octanoic acid starts to hydrolyze to generate a strong acid, but the acid reacts with sodium carbonate to maintain the pH of the solution at more than 5, so that the main agent reaction does not occur in the application. After the construction is finished, the sodium carbonate is consumed, the pH of the solution is less than 3 due to strong acid generated by hydrolysis of the n-octanoic acid, and the reaction is vigorously carried out.

Example 5:

the construction site comprises an oil pumping machine, a well mouth, a blowout pipeline, a pump truck, a main agent tank truck, a catalyst and a square tank.

When the oil well is unblocked, the solvent prepared in the square tank is squeezed into the well mouth by a pump truck, and the oil well is blown out through the blow-out pipe line after the squeezing is finished.

Claims

1. A chemical formula process for removing organic matter blockage in an oil well near-well zone is characterized by comprising the following steps of: the formula process comprises the following process steps: the formula mainly comprises four parts of a main agent, a catalyst A, a control agent B and a time delay agent C, wherein the main agent is ammonium chloride or sodium nitrite and water; the catalyst n-octanoic acid A is an organic matter which can be slowly hydrolyzed to generate strong acid, and the chemical formula of the catalyst is R-H; the control agent is sodium sulfate B which is weak base and has a chemical formula of R-OH; the time-delay agent gasoline C is an organic solvent, when the time-delay agent gasoline C is prepared, firstly, main agent water, ammonium chloride and control agent B sodium sulfate are dissolved together, and are uniformly stirred to form a first component, then, the catalyst n-octanoic acid A and the time-delay agent gasoline C are mixed and dissolved together to form a second component, then the two components are placed in a tank body according to a certain proportion, and finally, the two components are extruded into a shaft by a cement pump truck.