Profile control and displacement, profile control and water shutoff organic chromium cross-linking agent for oil extraction and compound preparation method of organic chromium cross-linking agent

Abstract

The invention belongs to the technical field of profile control and displacement, profile control and water shutoff for oil extraction in an oil field, and discloses a profile control and displacement, profile control and water shutoff organic chromium cross-linking agent for oil extraction and a compound preparation method of the organic chromium cross-linking agent. An agent A comprises 45%-62% of organic acid chromium salt, 0.05%-0.2% of inorganic acid, 3.5%-8.5% of a stabilizer and the balance water; and the agent B comprises 2.8%-7.5% of a complexing agent, 0.05%-3.33% of inorganic base and the balance of water. The preparation method comprises the following steps: respectively preparing the agent A and the agent B, pumping the agent B into a reaction kettle of the agent A according to a ratio under the condition of stirring, and stirring for 10 minutes to obtain a uniform dark green liquid product, namely the profile control and displacement, profile control and water shutoff organic chromium cross-linking agent product for oil extraction. The production process and equipment are simple, the quality is convenient to control, the environmental pollution is small, the risk in the production process is low, the ratio of the agent A to the agent B can be optimized according to the technical requirements of site construction, and the ion concentration of the effective substance Cr < 3 + > and the gelling time are controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of displacement control, profile control and water plugging for oil field production, in particular to the technical field of compound production of organic chromium cross-linking agents for displacement control, profile control and water plugging for oil production. The invention relates to an organic chromium cross-linking agent for displacement control, profile control and water plugging for oil production and a compound preparation method thereof. Background Art

[0002] With the long-term water injection development of oil fields, the heterogeneity of the reservoir leads to the injected water flowing along the high permeability area with less resistance and bypassing the low permeability high resistance area during the water drive process, forming an area that the injected fluid cannot reach. This will result in low crude oil recovery in the medium and low permeability layers, poor oil recovery effect, and seriously affect the development effect of water drive. Cross-linked polymer technology has been applied and promoted in many oil fields and has become the main technical means to improve crude oil recovery. Using cross-linked polymer technology, in the process of implementing field tests for adjustment and displacement, profile control, and water plugging, commonly used cross-linking agents include organic chromium system, phenolic profile control, bulk particles, petroleum resin, etc. Among them, the organic chromium cross-linking agent system is the most widely used in adjustment and displacement, profile control, and water plugging, which to a certain extent alleviates the contradictions within the oil layer.

[0003] The production process of organic chromium crosslinkers for oil production is mainly divided into two types: redox chromium production method and inorganic chromium-complex. The redox chromium production method uses dichromate and a reducing agent to react. There are side reactions in the production process, the preparation process is complicated, the reaction has associated irritating gases, and the production residues are toxic and easy to pollute the environment. Inorganic chromium-complex production of organic chromium crosslinkers often uses trivalent inorganic chromium salts as the main raw material and organic acids or organic acid salts as complexing agents. This method has a high proportion of complexing agent addition, otherwise the gelling time of the polymer crosslinker is too short to meet the needs of on-site construction.

[0004] In summary, in order to further improve the performance of organic chromium cross-linking agent products, it is of great significance to develop organic chromium cross-linking agents for oil production with simple production process and equipment, easy quality control and low environmental pollution for oil displacement, profile control and water plugging. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide an organic chromium cross-linking agent for oil production, profile control and water plugging, which uses organic acid chromium salt as the main raw material and has the characteristics of simple production process and equipment, easy quality control and low environmental pollution, and a preparation method thereof.

[0006] The organic chromium cross-linking agent for oil production is produced in a compound production method. The production process and equipment are simple, the product quality is easy to control, the production process has low risks, and no irritating gas is generated.

[0007] The present invention provides an organic chromium cross-linking agent for oil recovery, profile control and water plugging, which is composed of agent A and agent B in a mass ratio of 3:1-1:3; the mass fractions of the components are as follows:

[0008] Agent A: 45-62% organic acid chromium salt, 0.05%-0.2% inorganic acid, 3.5%-8.5% stabilizer, and the balance is water.

[0009] Agent B: 2.8%-7.5% complexing agent, 0.05%-3.33% inorganic base, and the balance is water.

[0010] Specifically, the organic acid chromium salt in agent A is liquid chromium acetate with a content of 50%. The inorganic acid is one or more of hydrochloric acid, sulfuric acid, and phosphoric acid, preferably hydrochloric acid; the stabilizer is one or more of sodium thiosulfate, thiourea, hydroxylamine hydrochloride, and sodium sulfite, preferably thiourea;

[0011] Specifically, the complexing agent in agent B is one or a combination of lactic acid, oxalic acid, and citric acid; the inorganic base is one or more of sodium hydroxide and sodium carbonate, preferably sodium hydroxide;

[0012] A method for preparing an organic chromium cross-linking agent A for oil recovery, profile control and water plugging, comprising the following steps:

[0013] According to the ratio of each component in Agent A, part of water is added to the reactor, and at room temperature, a stabilizer is added to the reactor, stirred for 10-30 minutes to dissolve the stabilizer evenly, and then an organic acid chromium salt is added to the reactor, stirred for 8-12 minutes, and then an inorganic acid is added to adjust the pH to 5-6.5 to obtain the crosslinking agent Agent A.

[0014] According to the ratio of each component in Agent B, add part of water to another reactor, add a complexing agent to the reactor at room temperature, stir for 10-15 minutes to dissolve the complexing agent evenly, then add an inorganic base to the reactor, stir for 5-10 minutes, and adjust the pH value to 7-8 to obtain the crosslinking agent Agent B.

[0015] While stirring, pump agent B into the reactor of agent A according to the proportion and stir for 10 minutes to obtain a uniform dark green liquid product, which is an organic chromium cross-linking agent product for oil recovery, profile control and water plugging.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The preparation method of the organic chromium cross-linking agent for oil recovery, profile control and water plugging has the advantages of simple production process and equipment, easy quality control, small environmental pollution, low production process risk, etc., and can also optimize the ratio of agent A to agent B according to the technical requirements of on-site construction, control the effective Cr 3+Ion concentration and gelation time. DETAILED DESCRIPTION

[0018] The present invention is described in detail below by specific examples, but the protection scope of the present invention is not limited. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0019] Embodiment 1:

[0020] Production of organic chromium crosslinking agent A: add 455 kg of water to a reactor, add 45 kg of thiourea to the reactor at room temperature, stir for 15 minutes to dissolve the stabilizer evenly, then add 500 kg of 50% chromium acetate to the reactor, stir for 10 minutes, add 0.8 kg of hydrochloric acid, adjust the pH to 6.0, and obtain the crosslinking agent A.

[0021] Production of organic chromium crosslinking agent B: add 920 kg of water to another reactor, add 55 kg of lactic acid to the reactor at room temperature, stir for 10 minutes to dissolve the lactic acid evenly, then add 24.4 kg of sodium hydroxide to the reactor, stir for 5 minutes, adjust the pH value to 7.0, and obtain the crosslinking agent B.

[0022] While stirring, pump agent B into the reactor of agent A and stir for 10 minutes to obtain a uniform dark green liquid product, which is 2 tons of organic chromium cross-linking agent product for oil production, displacement control, profile control and water plugging.

[0023] A 2000 ppm polyacrylamide solution was prepared using simulated water, and the above-mentioned 1500 ppm cross-linking agent was added. The gelation time was 8 h, and the gelation viscosity was 19750 mPa·s.

[0024] Embodiment 2:

[0025] Production of organic chromium crosslinking agent A: add 420 kg of water to a reactor, add 80 kg of thiourea to the reactor at room temperature, stir for 20 minutes to dissolve the stabilizer evenly, then add 600 kg of 50% chromium acetate to the reactor, stir for 10 minutes, add 1 kg of hydrochloric acid, adjust the pH to 6.0, and obtain the crosslinking agent A.

[0026] Production of organic chromium crosslinking agent B: add 1804 kg of water to another reactor, add 120 kg of lactic acid and 20 kg of oxalic acid to the reactor at room temperature, stir for 10 minutes to dissolve the lactic acid and oxalic acid evenly, then add 57 kg of sodium hydroxide to the reactor, stir for 5 minutes, adjust the pH value to 7.0, and obtain the crosslinking agent B.

[0027] While stirring, pump agent B into the reactor of agent A and stir for 10 minutes to obtain a uniform dark green liquid product, which is 3 tons of organic chromium cross-linking agent product for oil production, displacement control, profile control and water plugging.

[0028] A 2500 ppm polyacrylamide solution was prepared using on-site sewage, and the above-mentioned 2000 ppm cross-linking agent was added. The gelation time was 9 h, and the gelation viscosity was 36840 mPa·s.

[0029] Embodiment 3:

[0030] Production of organic chromium crosslinking agent A: add 455 kg of water to a reactor, add 45 kg of thiourea to the reactor at room temperature, stir for 15 minutes to dissolve the stabilizer evenly, then add 500 kg of 50% chromium acetate to the reactor, stir for 10 minutes, add 0.8 kg of hydrochloric acid, adjust the pH to 6.0, and obtain the crosslinking agent A.

[0031] Production of organic chromium crosslinking agent B: add 468 kg of water to another reactor, add 20 kg of lactic acid to the reactor at room temperature, stir for 10 minutes to dissolve the lactic acid evenly, then add 12.2 kg of sodium hydroxide to the reactor, stir for 5 minutes, adjust the pH value to 7.0, and obtain the crosslinking agent B.

[0032] While stirring, pump agent B into the reactor of agent A and stir for 10 minutes to obtain a uniform dark green liquid product, which is 1.5 tons of organic chromium cross-linking agent product for oil production, displacement control, profile control and water plugging.

[0033] A 1800 ppm polyacrylamide solution was prepared using simulated water, and the above-mentioned 1500 ppm cross-linking agent was added. The gelation time was 6 h, and the gelation viscosity was 17600 mPa·s.

[0034] The above-described embodiments are only preferred embodiments of the present invention, but not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. An organic chromium cross-linking agent for oil recovery, profile control and water plugging, characterized in that: It is composed of agent A and agent B in a mass ratio of 3:1-1:3, and the mass fraction of each component is as follows: Agent A: 45-62% organic acid chromium salt, 0.05%-0.2% inorganic acid, 3.5%-8.5% stabilizer, and the balance is water; Agent B: 2.8%-7.5% complexing agent, 0.05%-3.33% inorganic base, and the balance is water.

2. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 1, characterized in that: The organic acid chromium salt in agent A is liquid chromium acetate with a mass fraction of 50%.

3. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 1, characterized in that: The inorganic acid is one or more of hydrochloric acid, sulfuric acid and phosphoric acid.

4. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 3, characterized in that: The inorganic acid is hydrochloric acid.

5. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 1, characterized in that: The stabilizer is one or more of sodium thiosulfate, thiourea, hydroxylamine hydrochloride and sodium sulfite.

6. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 5, characterized in that: The stabilizer is thiourea.

7. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 1, characterized in that: The complexing agent in Agent B is one or a combination of two of lactic acid, oxalic acid and citric acid.

8. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 1, characterized in that: The inorganic base is one or more of sodium hydroxide and sodium carbonate.

9. The organic chromium cross-linking agent for oil recovery, profile control and water plugging according to claim 8, characterized in that: The inorganic base is sodium hydroxide.

10. A method for preparing an organic chromium cross-linking agent A for oil recovery, profile control and water plugging, characterized in that: The steps include: According to the ratio of each component in Agent A, add part of water to the reactor, add stabilizer to the reactor at room temperature, stir for 10-30 minutes to dissolve the stabilizer evenly, then add organic acid chromium salt to the reactor, stir for 8-12 minutes, add inorganic acid, adjust the pH to 5-6.5, and obtain crosslinking agent A; According to the ratio of each component in Agent B, add part of water to another reaction kettle, add a complexing agent to the reaction kettle at room temperature, stir for 10-15 minutes to dissolve the complexing agent evenly, then add an inorganic base to the reaction kettle, stir for 5-10 minutes, and adjust the pH value to 7-8 to obtain a crosslinking agent B; While stirring, pump agent B into the reactor of agent A according to the proportion and stir for 10 minutes to obtain a uniform dark green liquid product.