A heavy oil double-effect oil-increasing composite slug chemical agent and a heavy oil double-effect production-increasing process method

Abstract

The present invention belongs to the field of heavy oil exploitation in petroleum development, and discloses a heavy oil double-effect oil-increasing composite slug chemical agent and a heavy oil double-effect production-increasing process method. The composite slug chemical agent comprises an aqueous solution of a bio-enzyme stripping crude oil agent and an aqueous solution of a self-emulsifying viscosity-reducing agent; the bio-enzyme stripping crude oil agent in the aqueous solution of the bio-enzyme stripping crude oil agent comprises a protein-complex enzyme and a stabilizer; the self-emulsifying viscosity-reducing agent in the aqueous solution of the self-emulsifying viscosity-reducing agent comprises an emulsifier and a penetrant. The present invention proposes a double-effect slug injection, which improves the contact degree between the viscosity-reducing agent and the formation crude oil, efficiently utilizes the self-emulsifying viscosity-reducing agent, and ultimately improves the oil well recovery rate.

Description

Technical Field

[0001] The invention belongs to the field of petroleum development and heavy oil exploitation, and more specifically, relates to a heavy oil double-effect oil-increasing composite slug chemical agent and a heavy oil double-effect production-increasing process method. Background Art

[0002] my country has extremely rich heavy oil resources, and the development technology of heavy oil has attracted much attention. How to reduce the viscosity of heavy oil and improve its fluidity is the key to solving the problems of heavy oil mining, gathering and refining. Common heavy oil viscosity reduction methods at home and abroad mainly include thermal viscosity reduction mining method and chemical viscosity reduction mining method. Chemical viscosity reduction method is a widely used and effective viscosity reduction method for heavy oil wells. At present, the laboratory effect of most viscosity reducers is very significant, and some viscosity reduction rates have reached more than 90%, or even 99%. However, the oil increase effect of these viscosity reducers after being injected into the formation is not satisfactory. Some viscosity reducers cannot achieve the ideal effect. The main reason is that most of the viscosity reducers injected into the well are spit out before they can contact the crude oil. As a result, the oil increase efficiency is greatly reduced, the cost is increased, and the large-scale application of high-efficiency viscosity reducers in oilfield development is restricted. Faced with the problem of low actual application effect, most oil fields adopt composite viscosity reduction process technology, for example, chemical viscosity reduction technology is combined with steam huff and puff, dilution, nitrogen injection, catalytic viscosity reduction, etc. to improve the viscosity reduction effect. These technical methods have achieved good results. However, firstly, the application cost of process technology has increased significantly, and the process requirements, such as anti-corrosion and pipe string requirements, have increased; secondly, in the later stage of multiple rounds of heavy oil reservoir development, the viscosity of crude oil has further increased, the water recovery rate has decreased, and the formation deficit has become serious, resulting in a shorter production time of the throughput cycle and a low recovery rate. The effects of these auxiliary technologies have also become increasingly poor. Therefore, how to efficiently use viscosity reducers is currently an urgent need, that is, first of all, in addition to the high viscosity reduction rate, the injection system must have good compatibility with the contacting formation and fluid. Secondly, the volume of the sweep coefficient of the injection fluid after injection is required to be high, and it must enter the appropriate pores to contact the crude oil adhering to the rock, reducing the probability of the viscosity reducer being discharged without contacting the crude oil, thereby improving efficiency. In summary, there are several issues that need to be addressed when injecting viscosity reducers: first, the injected fluid must have a good viscosity reducing effect to ensure an effective viscosity reduction rate; second, the injected fluid must also have a good stripping ability to strip off the remaining oil attached to the core, emulsify and disperse it, and flow it out; third, the injected fluid must have a high swept volume so that the injected viscosity reducer can contact more formation crude oil and improve the effective utilization of the viscosity reducer.

[0003] Therefore, in order to improve the efficiency of viscosity reducers and the recovery rate of heavy oil, it is urgent to propose a new heavy oil double-effect oil-increasing composite slug chemical agent and a heavy oil double-effect production-increasing process method. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art and propose a heavy oil double-effect oil-increasing composite slug chemical agent and a heavy oil double-effect production-increasing process method. The present invention proposes double-effect slug injection, which improves the contact degree between the viscosity reducer and the formation crude oil, efficiently utilizes the self-emulsifying viscosity reducer, and ultimately improves the oil well recovery rate.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides a heavy oil dual-effect oil-increasing composite slug chemical agent, the composite slug chemical agent comprising an aqueous solution of a biological enzyme stripping crude oil agent and an aqueous solution of a self-emulsifying viscosity reducing agent;

[0006] The bio-enzyme crude oil stripping agent in the aqueous solution of the bio-enzyme crude oil stripping agent comprises a protein-complex enzyme and a stabilizer;

[0007] The self-emulsifying viscosity reducer in the self-emulsifying viscosity reducer aqueous solution comprises an emulsifier and a penetrant.

[0008] The second aspect of the present invention provides a heavy oil double-effect production increasing process method, which adopts the heavy oil double-effect oil increasing composite slug chemical agent, and comprises the following steps:

[0009] The bio-enzyme crude oil stripping agent aqueous solution segment plug, the propulsion buffer solution, the self-emulsifying viscosity reducer aqueous solution segment plug and the displacement fluid are sequentially injected into the oil layer, and the well is opened for production after well soaking treatment.

[0010] The technical solution of the present invention has the following beneficial effects:

[0011] (1) The present invention proposes a dual-effect slug injection, wherein the front slug is a biological enzyme stripping crude oil agent slug, which mainly strips the residual oil in the core, expands or opens up new flow channels, and increases the swept volume of the injected liquid; the rear end plug is a self-emulsifying viscosity reducer slug, which effectively reduces the viscosity of the crude oil, and ultimately improves the crude oil recovery rate with dual effects.

[0012] (2) The present invention first injects a bio-enzyme stripping crude oil agent plug and then injects a self-emulsifying viscosity reducer plug, thereby saving 30-50% of the self-emulsifying viscosity reducer and improving the oil increase efficiency by more than 30%, thereby reducing the cost of using the on-site viscosity reducer and greatly improving the viscosity reduction efficiency.

[0013] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0014] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0015] The first aspect of the present invention provides a heavy oil dual-effect oil-increasing composite slug chemical agent, the composite slug chemical agent comprising an aqueous solution of a biological enzyme stripping crude oil agent and an aqueous solution of a self-emulsifying viscosity reducing agent;

[0016] The bio-enzyme crude oil stripping agent in the aqueous solution of the bio-enzyme crude oil stripping agent comprises a protein-complex enzyme and a stabilizer;

[0017] The self-emulsifying viscosity reducer in the self-emulsifying viscosity reducer aqueous solution comprises an emulsifier and a penetrant.

[0018] In the present invention, the self-emulsifying viscosity reducer is a GRJ system self-emulsifying viscosity reducer.

[0019] According to the present invention, preferably, the protein-complex enzyme is at least one of protein-complex enzyme AE9, protein-complex enzyme AE10 and protein-complex enzyme HAS.

[0020] According to the present invention, preferably, the stabilizer is a mixture of an inorganic base and an organic weak base in a mass ratio of (0.8-1.2): (0.8-1.2), the inorganic base is preferably sodium hydroxide, and the organic weak base is preferably urea. As a preferred embodiment, the stabilizer is a mixture of an inorganic base and an organic weak base in a mass ratio of 1:1.

[0021] According to the present invention, preferably, the emulsifier is OP series surfactant and / or Tween 60.

[0022] The penetrant is lignin PS.

[0023] According to the present invention, preferably, the mass concentration of the bio-enzyme stripping crude oil agent in the bio-enzyme stripping crude oil agent aqueous solution is determined according to the specific conditions of the oil reservoir, and is preferably 0.1-3%.

[0024] According to the present invention, preferably, the mass concentration of the self-emulsifiable viscosity reducer in the self-emulsifiable viscosity reducer aqueous solution is determined according to the specific conditions of the oil reservoir, and is preferably 0.1-3%.

[0025] According to the present invention, preferably, the mass ratio of the protein-complex enzyme to the stabilizer is (5-10):1.

[0026] According to the present invention, preferably, the mass ratio of the emulsifier to the penetrant is (8-12):1.

[0027] According to the present invention, preferably, the method for preparing the aqueous solution of the bio-enzyme stripping crude oil agent includes mixing water with the protein-complex enzyme and the stabilizer while stirring; as a preferred embodiment, the method for preparing the aqueous solution of the bio-enzyme stripping crude oil agent includes first adding a certain mass of water, and then adding the protein-complex enzyme and the stabilizer according to the mass ratio while continuously stirring.

[0028] According to the present invention, preferably, the method for preparing the self-emulsifying viscosity reducer aqueous solution comprises mixing water with the emulsifier and the penetrant while stirring; as a preferred embodiment, the method for preparing the self-emulsifying viscosity reducer aqueous solution comprises first adding a certain mass of water, and then adding the emulsifier and the penetrant according to the mass ratio while continuously stirring.

[0029] The preparation temperatures of the aqueous solution of the bio-enzyme crude oil stripping agent and the aqueous solution of the self-emulsifying viscosity reducing agent are independently 50-60°C.

[0030] According to the present invention, preferably, in the heavy oil dual-effect oil-increasing composite slug chemical agent, the dosage of the biological enzyme stripping crude oil agent aqueous solution and the dosage of the self-emulsifying viscosity reducing agent aqueous solution are independently designed according to the conditions such as the single well oil layer and the perforation thickness. As a preferred solution, it is calculated according to formula (1):

[0031] V=πKn(R 2 -r 2 )×h×φ formula (1),

[0032] in:

[0033] V-the amount of two slugs, in m 3 ;

[0034] R, r-the distal and proximal radii of the oil well treatment of the bio-enzyme crude oil stripping agent slug and the self-emulsifying viscosity reducing agent slug, respectively, in m;

[0035] h-effective thickness of oil layer, in m;

[0036] Φ-effective porosity of oil layer, in %;

[0037] K-formation fluid intermixing coefficient, the value of which is related to reservoir conditions, injection rate and pressure, and preferably, the value is 1.1 to 1.3;

[0038] n-formation adsorption coefficient, the value of which is related to reservoir conditions, porosity and formation lithology, and is preferably 1.1 to 1.3.

[0039] The second aspect of the present invention provides a heavy oil double-effect production increasing process method, which adopts the heavy oil double-effect oil increasing composite slug chemical agent, and comprises the following steps:

[0040] The bio-enzyme crude oil stripping agent aqueous solution segment plug, the propulsion buffer solution, the self-emulsifying viscosity reducer aqueous solution segment plug and the displacement fluid are sequentially injected into the oil layer, and the well is opened for production after well soaking treatment.

[0041] In the present invention, the first step is to inject the biological enzyme stripping crude oil aqueous solution segment plug, firstly strip and disperse the contacted formation crude oil and rock, expand or form a new flow channel, and disperse the stripped crude oil into the biological enzyme and the subsequent hot water segment plug, thereby increasing the segment plug viscosity, improving the front streamline distribution of the injected fluid, and expanding the swept volume, providing a favorable environment for the subsequent self-emulsifying viscosity reducer; the second step is to inject the self-emulsifying viscosity reducer aqueous solution segment plug, and the self-emulsifying viscosity reducer makes the W / O emulsion invert into an O / W emulsion to reduce the viscosity. With the stripping, dispersing and channel opening effects of the biological enzyme in the first step, the viscosity reducer is more in contact with the crude oil, the amount of the self-emulsifying viscosity reducer used can be reduced by 30-50%, and the oil recovery efficiency is further improved.

[0042] According to the present invention, preferably, the injection displacement of the bio-enzyme stripping crude oil aqueous solution slug and the injection displacement of the self-emulsifying viscosity reducing agent aqueous solution slug are each independently 3-5m 3 / h.

[0043] According to the present invention, preferably, the propulsion buffer is hot water with a temperature of 50-60°C, and the amount of the propulsion buffer is 0.4-0.6 times the amount of the bio-enzyme stripping crude oil agent aqueous solution, which plays a propulsion and buffering role.

[0044] According to the present invention, preferably, the displacement fluid is hot water with a temperature of 50-60°C, and the amount of the displacement fluid is determined according to the oil well parameters. As a preferred solution, the amount of the displacement fluid is designed and determined by the geological department according to the oil well parameters (for example, oil layer thickness, oil well pressure, permeability, etc.).

[0045] According to the present invention, preferably, the duration of the soaking treatment is 2-3 days.

[0046] The present invention is specifically described below by way of examples.

[0047] Example 1

[0048] This embodiment provides a heavy oil dual-effect oil-increasing composite slug chemical agent, the composite slug chemical agent comprising an aqueous solution of a biological enzyme stripping crude oil agent and an aqueous solution of a self-emulsifying viscosity reducing agent;

[0049] The bio-enzyme stripping crude oil agent in the aqueous solution of the bio-enzyme stripping crude oil agent includes protein-complex enzyme AE9 and a stabilizer, and the stabilizer is a mixture of sodium hydroxide and urea in a mass ratio of 1:1; the mass concentration of the bio-enzyme stripping crude oil agent in the aqueous solution of the bio-enzyme stripping crude oil agent is 0.3%, and the mass ratio of the protein-complex enzyme AE9 and the stabilizer is 5:1; the method for preparing the aqueous solution of the bio-enzyme stripping crude oil agent includes first adding a certain mass of water, and then adding the protein-complex enzyme and the stabilizer in a mass ratio while stirring continuously. The average preparation temperature of the aqueous solution of the bio-enzyme stripping crude oil agent is 55°C

[0050] The self-emulsifying viscosity reducer in the self-emulsifying viscosity reducer aqueous solution includes an emulsifier OP-10 and a penetrant lignin PS. The mass concentration of the self-emulsifying viscosity reducer in the self-emulsifying viscosity reducer aqueous solution is 0.5%, and the mass ratio of the emulsifier to the penetrant is 10:1. The method for preparing the self-emulsifying viscosity reducer aqueous solution includes first adding a certain mass of water, and then adding the emulsifier and the penetrant according to the mass ratio while stirring continuously. The average preparation temperature of the self-emulsifying aqueous solution is 55°C.

[0051] In this implementation, the heavy oil double-effect production increase composite slug chemical agent was used to implement 6 heavy oil double-effect production increase wells at a heavy oil field in the west. The heavy oil double-effect production increase process method includes the following steps:

[0052] The bio-enzyme crude oil stripping agent aqueous solution segment plug, the propulsion buffer solution, the self-emulsifying viscosity reducer aqueous solution segment plug and the displacement fluid are sequentially injected into the oil layer, and the well is opened for production after the well is soaked for 2-3 days.

[0053] The dosage of the bio-enzyme crude oil stripping agent aqueous solution and the dosage of the self-emulsifying viscosity reducing agent aqueous solution are independently designed according to the single well oil layer and perforation thickness, and are specifically calculated according to formula (1):

[0054] V=πKn(R 2 -r 2 )×h×φ formula (1),

[0055] in:

[0056] V-the amount of two slugs, in m 3 ;

[0057] R, r-the distal and proximal radii of the oil well treatment of the bio-enzyme crude oil stripping agent slug and the self-emulsifying viscosity reducing agent slug, respectively, in meters;

[0058] h-effective thickness of oil layer, in m;

[0059] Φ-effective porosity of oil layer, in %;

[0060] K-formation fluid intermixing coefficient, the value is 1.1~1.3;

[0061] n- formation adsorption coefficient, the value is 1.1~1.3.

[0062] The injection displacement of the bio-enzyme stripping crude oil aqueous solution segment and the injection displacement of the self-emulsifying viscosity reducing agent aqueous solution segment are independently 4m 3 / h.

[0063] The propulsion buffer is hot water with a temperature of 50-60°C, and the amount of the propulsion buffer is 0.5 times the amount of the biological enzyme stripping crude oil agent aqueous solution; the displacement fluid is hot water with a temperature of 50-60°C, and the amount of the displacement fluid is one-third of the total amount of the biological enzyme stripping crude oil agent aqueous solution and the self-emulsifying viscosity reducer aqueous solution according to the design requirements of the geological department.

[0064] The field application effect analysis of the double-effect production increase of heavy oil is as follows: after the injection of the bio-enzyme stripping crude oil agent, the average injection pressure increased from 4MPa to 10MPa. Compared with the previous test cycle, the opening fluid volume of the 6 wells after the test showed a significant increase. The cost and oil increase effect comparison is: saving 45% of the self-emulsifying viscosity reducer, excluding the cost of injecting the bio-enzyme stripping crude oil agent, the total cost is reduced by 20%, the average daily oil production of a single well is increased by 1.3t / d, and the total oil increase during the statistical period is 1914t.

[0065] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A heavy oil double-effect oil-increasing composite slug chemical agent, characterized in that: The composite slug chemical agent comprises an aqueous solution of a biological enzyme stripping crude oil agent and an aqueous solution of a self-emulsifying viscosity reducing agent; The bio-enzyme crude oil stripping agent in the aqueous solution of the bio-enzyme crude oil stripping agent comprises a protein-complex enzyme and a stabilizer; The mass concentration of the bio-enzyme crude oil stripping agent in the aqueous solution of the bio-enzyme crude oil stripping agent is 0.1-3%; The mass ratio of the protein-complex enzyme to the stabilizer is (5-10):1; The stabilizer is a mixture of an inorganic base and an organic weak base in a mass ratio of (0.8-1.2): (0.8-1.2); the inorganic base is sodium hydroxide, and the organic weak base is urea; The self-emulsifying viscosity reducer in the self-emulsifying viscosity reducer aqueous solution comprises an emulsifier and a penetrant; The mass concentration of the self-emulsifying viscosity reducer in the self-emulsifying viscosity reducer aqueous solution is 0.1-3%; The mass ratio of the emulsifier to the penetrant is (8-12):1; In the heavy oil dual-effect oil-increasing composite slug chemical agent, the dosage of the biological enzyme crude oil stripping agent aqueous solution and the dosage of the self-emulsifying viscosity reducing agent aqueous solution are independently calculated according to formula (1): V=πKn(R 2 -r 2 )×h×φ formula (1), in: V-the amount of two slugs, in m 3 ; R, r-the distal and proximal radii of the oil well treatment of the bio-enzyme crude oil stripping agent slug and the self-emulsifying viscosity reducing agent slug, respectively, in meters; h-effective thickness of oil layer, in m; Φ-effective porosity of oil layer, in %; K-formation fluid mixing coefficient, the value is 1.1~1.3; n- formation adsorption coefficient, the value is 1.1~1.

3.

2. The heavy oil double-effect oil-increasing composite slug chemical agent according to claim 1, wherein: The protein-complex enzyme is at least one of protein-complex enzyme AE9, protein-complex enzyme AE10 and protein-complex enzyme HAS; The emulsifier is OP series surfactant and / or Tween 60; The penetrant is lignin PS.

3. The heavy oil double-effect oil-increasing composite slug chemical agent according to claim 1, wherein: The method for preparing the aqueous solution of the bio-enzyme crude oil stripping agent comprises mixing water with the protein-complex enzyme and the stabilizer while stirring; The method for preparing the aqueous solution of the self-emulsifying viscosity reducer comprises mixing water with the emulsifier and the penetrant while stirring; The preparation temperatures of the aqueous solution of the bio-enzyme crude oil stripping agent and the aqueous solution of the self-emulsifying viscosity reducing agent are independently 50-60°C.

4. A heavy oil double-effect production increasing process, characterized in that: The method adopts the heavy oil dual-effect oil-increasing composite slug chemical agent according to any one of claims 1 to 3, and comprises the following steps: The bio-enzyme crude oil stripping agent aqueous solution segment plug, the propulsion buffer solution, the self-emulsifying viscosity reducer aqueous solution segment plug and the displacement fluid are sequentially injected into the oil layer, and the well is opened for production after well soaking treatment.

5. The heavy oil double-effect production increasing process according to claim 4, wherein: The injection displacement of the bio-enzyme stripping crude oil aqueous solution segment and the injection displacement of the self-emulsifying viscosity reducing agent aqueous solution segment are independently 3-5m 3 / h.

6. The heavy oil double-effect production increasing process according to claim 4, wherein: The propulsion buffer is hot water with a temperature of 50-60° C. The amount of the propulsion buffer is 0.4-0.6 times the amount of the bio-enzyme stripping crude oil agent aqueous solution; The displacement fluid is hot water with a temperature of 50-60° C. The amount of the displacement fluid is determined according to the oil well parameters.

7. The heavy oil double-effect production increasing process according to claim 4, wherein: The duration of the well soaking treatment is 2-3 days.