Underground radio frequency heavy oil heating control method based on antenna array distribution

Abstract

The invention relates to an antenna array distribution-based underground radio-frequency heavy oil heating control method, which comprises the following specific steps that: during initial heating, a plurality of antennas heat a heavy oil reservoir in a region where the antennas are located at the same output power q, and after the heating time lasts for t1, the oil extraction volume is V1 and the energy-oil ratio is delta1; along with long-time heating and extraction of more heavy oil to the ground, the energy-oil ratio is increased, the energy consumption is increased, at the moment, the output power of the multiple antennas is different from qn, part of the antennas are started in sequence to heat the heavy oil reservoir in the region where the antennas are located, at the moment, after the heating time lasts for t2, the oil extraction volume is V2, and the energy-oil ratio is delta2; heating is continuously carried out, when the energy-oil ratio is increased again, the operation is repeated for m times, the energy-oil ratio is delta m + 1, and heating and oil extraction in the area where the underground radio frequency heating equipment is located are stopped until (delta m-delta m + 1) / delta m is smaller than 0.1. The heating output power is improved, the heavy oil heating area and the extraction efficiency are improved, low-energy-consumption heating is achieved, and energy conservation and environmental protection are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas development, in particular to a downhole radio frequency heating heavy oil control method based on antenna array distribution. BACKGROUND

[0002] As one of conventional oil and gas resources, the remaining recoverable reserves of heavy oil have exceeded the remaining proven reserves of conventional crude oil. Effective development of heavy oil resources is of great importance to the energy security of China. However, the characteristics of high viscosity, high density and poor flowability of heavy oil and super heavy oil seriously hinder the large-scale and efficient development of heavy oil resources.

[0003] The most widely used technology at present is the steam thermal recovery method, mainly including steam huff and puff technology, steam flooding technology, steam assisted gravity drainage technology, etc. However, the defects of "high carbon emission", "high energy consumption" and "low efficiency" of the steam method cannot meet the needs of heavy oil development, mainly manifested as large occupation area, consumption of large amount of water resources, difficulty in developing deep, thin and fractured reservoirs of heavy oil resources, and serious heat loss of steam in the pipeline, low heating efficiency and poor economy. SUMMARY

[0004] The present application provides a downhole radio frequency heating heavy oil control method based on antenna array distribution, aiming to solve the problems in the prior art.

[0005] The technical solution of the present application to solve the above technical problems is as follows:

[0006] A downhole radio frequency heating heavy oil control method based on antenna array distribution, comprising the following specific steps:

[0007] S1: At the initial heating, a plurality of antennas heat the heavy oil reservoir in the region with the same output power q. After the heating time lasts t1, the oil production volume is V1, and the energy oil ratio is δ1;

[0008] S2: With long-time heating and more heavy oil being exploited to the ground, the energy oil ratio increases, and the energy consumption increases. At this time, the output powers of the plurality of antennas are different q n , and part of the antennas are sequentially turned on to heat the heavy oil reservoir in the region. After the heating time lasts t2, the oil production volume is V2, and the energy oil ratio is δ2;

[0009] Select δ2 less than δ1, and heat the heavy oil reservoir in the region with the antennas and power corresponding to the minimum δ2 selected from δ2;

[0010] S3: The heating continues, and when the energy oil ratio increases again (> δ2), the operation of S2 is repeated, and the energy oil ratio is δ m+1 , until (δ m - δ m+1 ) / δm If the value is less than 0.1, it indicates that oil extraction in this area is complete, and heating and oil extraction in the area where the downhole radio frequency heating equipment is located will be stopped.

[0011] The beneficial effects of this invention are: the heavy oil control method provided by this invention is simple, improves the output power of heating, increases the heating area and extraction efficiency of heavy oil, and achieves low-energy heating, which is energy-saving and environmentally friendly.

[0012] Based on the above technical solution, the present invention can be further improved as follows.

[0013] Furthermore, after the output power q of the multiple antennas in S1 and the heating time t1, the oil extraction volume is V1, and the oil-energy ratio δ1 satisfies the following formula:

[0014] δ1=(q·n)t1 / V1;

[0015] The unit of antenna output power q is W, the unit of heating time t1 is h, and the unit of oil extraction volume V1 is m³. 3 The unit of δ1 is J / m 3 , where n is the number of antennas.

[0016] The beneficial effect of adopting the above-mentioned further scheme is that the above formula can reflect the energy consumption of multiple antennas within a set heating time, so as to compare it with the energy consumption of subsequent oil extraction, thereby selecting a heating method with lower energy consumption, saving energy and protecting the environment.

[0017] Furthermore, the output power q of the multiple antennas in S2 n The heating time duration t2, the oil production volume V2, and the energy-to-oil ratio δ2 satisfy the following formula:

[0018] δ2=(q1+q2+q3+q4+q5+......+q n )t2 / V2;

[0019] Where n is the number of antennas.

[0020] The beneficial effect of adopting the above-mentioned further scheme is that the above formula can reflect the energy consumption of multiple antennas within a set heating time, so as to compare it with the energy consumption of previous oil extraction, thereby selecting a heating method with lower energy consumption, saving energy and protecting the environment.

[0021] Furthermore, δ1 in S1 and δ2 in S2 satisfy the following relationship:

[0022] (δ1-δ2) / δ1≥10%.

[0023] The beneficial effect of adopting the above-mentioned further scheme is that δ1 and δ2 satisfy the above relationship, resulting in lower energy consumption and energy saving and environmental protection.

[0024] Further, the S3 further comprises S4:

[0025] The radio frequency heating equipment is axially moved to a new reservoir area, and the oil and gas heating development is carried out according to the operations of the S1, the S2 and the S3.

[0026] The above further scheme has the beneficial effect that the method is simple and the design is reasonable, so that the heavy oil resources in the set area are regionally and directionally exploited.

[0027] Further, the multiple antennas opened each time in the S2 are arranged in series.

[0028] The above further scheme has the beneficial effect that the antennas opened each time are reasonably distributed, so that the heavy oil storage in the set area is heated and exploited, and energy saving and environmental protection are achieved.

[0029] Further, the number of antennas in the S1 and the S2 is six.

[0030] The above further scheme has the beneficial effect that the number of antennas is reasonably distributed, so that the heavy oil is heated and exploited, and the cost is saved.

[0031] Further, the multiple antennas in the S1 and the S2 are uniformly distributed in a circle.

[0032] The above further scheme has the beneficial effect that the multiple antennas are reasonably distributed, so that the heavy oil reservoir is heated and exploited.

[0033] Further, the multiple antennas in the S1 and the S2 are linear antennas.

[0034] The above further scheme has the beneficial effect that the heating performance of the linear antennas is more stable, so that the oil is conveniently extracted.

[0035] Further, the multiple antennas in the S1 are lowered into the work well by a pipe column.

[0036] The above further scheme has the beneficial effect that the method is simple and the design is reasonable, so that the antennas are lowered into the work well by the pipe column, and the work is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flow chart of the first embodiment in the present application;

[0038] Figure 2 The flow chart of the second embodiment in the present application;

[0039] Figure 3 The structural schematic diagram of the downhole radio frequency heating equipment based on the antenna array distribution in the present application;

[0040] Figure 4 Figure 1 is a structural schematic diagram of the downhole radio frequency heating equipment based on the antenna array distribution in the present application;

[0041] Figure 5 Figure 2 is a control direction schematic diagram of the multi-antenna heating in the present application.

[0042] In the drawings, the components represented by the respective reference numerals are listed as follows:

[0043] 1, antenna; 2, shell cylinder; 3, centralizer; 4, antenna power supply line; 5, temperature sensor; 6, temperature sensor power supply line; 7, pipe column; 8, wellbore; 9, heavy oil reservoir; 9-1, heavy oil containing reservoir area; 9-2, multi-antenna heating control direction. DETAILED DESCRIPTION

[0044] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0045] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0046] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0048] Embodiment 1

[0049] AsFigures 1 to 5 As shown, the embodiment provides a downhole radio frequency heating heavy oil control method based on antenna array distribution, comprising the following specific steps:

[0050] S1: When initially heating, multiple antennas 1 heat the heavy oil reservoir 9 in the region with the same output power q. After the heating time lasts t1, the oil production volume is V1, and the energy-oil ratio is δ1;

[0051] S2: As the heating time is long and more heavy oil is extracted to the ground, the energy-oil ratio increases, and the energy consumption increases. At this time, the output power of multiple antennas 1 is different q n , and part of the antennas 1 are sequentially turned on to heat the heavy oil reservoir 9 in the region. After the heating time lasts t2, the oil production volume is V2, and the energy-oil ratio is δ2;

[0052] Select δ2 less than δ1, and select the antenna 1 corresponding to the minimum δ2 from the selected δ2 to heat the heavy oil reservoir 9 in the region;

[0053] S3: When the energy-oil ratio increases again (> δ2), repeat the operation of S2, and reciprocate m times, until the energy-oil ratio is δ m+1 , and (δ m - δ m+1 ) / δ m is less than 0.1, indicating that the oil collection in this region is completed, and the heating and oil extraction in the region of the downhole radio frequency heating equipment are stopped.

[0054] The heavy oil control method provided by the embodiment is simple, improves the output power of heating, improves the heavy oil heating area and extraction efficiency, realizes low-energy-consumption heating, and saves energy and protects the environment.

[0055] Embodiment 2

[0056] On the basis of embodiment 1, in the embodiment, the output power q of multiple antennas 1 in S1, the heating time lasts t1, the oil production volume is V1, and the energy-oil ratio δ1 satisfies the following formula:

[0057] δ1 = (q·n)t1 / V1;

[0058] Wherein, the unit of antenna 1 output power q is W, the unit of heating time t1 is h (hour), the unit of oil production volume V1 is m 3 , the unit of δ1 is J / m 3 , and n is the number of antennas 1.

[0059] The above formula can reflect the energy consumption of multiple antennas in a set heating time, so as to compare the energy consumption of subsequent oil extraction, select a heating mode with relatively low energy consumption, save energy, and save energy and protect the environment.

[0060] Embodiment 3

[0061] In the above embodiments, the output power q of the plurality of antennas 1 in S2 n , the heating time duration t2, the oil production volume V2 and the energy-oil ratio δ2 satisfy the following formula:

[0062] δ2 = (q1+q2+q3+q4+q5+...+qn) t2 / V2 n

[0063] Wherein, n is the number of antennas 1.

[0064] In addition, the units of the above parameters remain the same as in Embodiment 2.

[0065] The above formula can reflect the energy consumption of multiple antennas in a set heating time, so as to compare with the energy consumption of previous oil production, so as to select the heating method with lower energy consumption, save energy and protect the environment.

[0066] Embodiment 4

[0067] In the above embodiments, δ1 in S1 and δ2 in S2 satisfy the following relationship:

[0068] (δ1-δ2) / δ1≥10%.

[0069] The energy consumption of δ1 and δ2 satisfying the above relationship is lower, which is energy-saving and environmentally friendly.

[0070] Embodiment 5

[0071] In the above embodiments, S3 is followed by S4:

[0072] The radio frequency heating equipment is moved along the wellbore axis to a new reservoir area, and the oil and gas heating development is carried out according to the operation of S1, S2 and S3.

[0073] The method is simple and reasonable in design, so as to carry out regional and directional exploitation of heavy oil resources in the set area.

[0074] Embodiment 6

[0075] In the above embodiments, the plurality of antennas 1 opened each time in S2 are arranged continuously.

[0076] The distribution of antennas opened each time is reasonable, so as to carry out heating exploitation of heavy oil storage in the set area, save energy and protect the environment.

[0077] Embodiment 7

[0078] ​On the basis of each of the above embodiments, in this embodiment, the number of the antennas 1 in the S1 and the S2 is six.

[0079] The number of the antennas 1 is reasonably distributed, which can not only meet the heating and mining of heavy oil, but also save the cost.

[0080] Embodiment 8

[0081] On the basis of each of the above embodiments, in this embodiment, the plurality of antennas 1 in the S1 and the S2 are uniformly distributed in a circle.

[0082] The plurality of antennas 1 are reasonably distributed, which facilitates the heating and mining of the heavy oil reservoir 9.

[0083] Alternatively, the antennas 1 can also be distributed in other reasonable manners, for example, in a rectangular manner.

[0084] Embodiment 9

[0085] On the basis of each of the above embodiments, in this embodiment, the plurality of antennas 1 in the S1 and the S2 are linear antennas.

[0086] The heating performance of the linear antenna is more stable, which facilitates oil production.

[0087] Embodiment 10

[0088] On the basis of each of the above embodiments, in this embodiment, the plurality of antennas 1 in the S1 are lowered into the working well by the pipe column 7.

[0089] The method is simple and reasonable in design, and the antennas 1 are lowered into the working well by the pipe column 7, which is convenient for operation.

[0090] The number of linear antennas n = 6 is used for the embodiment introduction, and the six linear antennas are uniformly distributed in the shell cylinder, and the specific steps are as follows:

[0091] (1) When initial heating, since the oil content of the heavy oil reservoir in the area where the downhole radio frequency heating equipment is located is sufficient in different directions along the wellbore, all antennas start heating, and the output power of the antennas is Q1 = Q2 = Q3 = Q4 = Q5 = Q6 = q > 0, q constant, after the heating time lasts t1, the oil production volume is V1, and the energy-oil ratio δ1 = (q·n)t1 / V1.

[0092] (2) With long-time heating and more heavy oil being mined to the ground, the energy-oil ratio increases (> δ1), the oil quantity is less, and the energy consumption increases;

[0093] At this time, the reservoir inside the area where the downhole radio frequency heating equipment is located has a significant decrease in oil content in different directions along the wellbore radius, and the degree of decrease in different directions is different, resulting in uneven distribution of heavy oil. Therefore, the heating direction needs to be controlled to the area with more oil content, and the values of the output powers Q1, Q2, Q3, Q4, Q5, and Q6 of the antennas are adjusted to q1, q2, q3, q4, q5, and q6 (q n ≥ 0, n = 1, 2, 3,..., 6, when q n = 0, the antenna stops power supply, and the output power is 0), and at this time, after the heating time continues for t2, the oil production volume is V2, and therefore the energy-oil ratio δ2 = (q1+q2+q3+q4+q5+q6)t2 / V2.

[0094] When (δ1-δ2) / δ1≥10% is satisfied, the values of q1, q2, q3, q4, q5, and q6 no longer change, and the remaining heavy oil resources in the reservoir inside the area where the downhole radio frequency heating equipment is located are continuously heated and exploited.

[0095] (3) The heating continues, the energy-oil ratio increases again (> δ2), and the energy consumption increases; therefore, the values of the output powers Q1, Q2, Q3, Q4, Q5, and Q6 of the antennas are adjusted again to q 11 , q 21 , q 31 , q 41 , q 51 , and q 61 (q n1 ≥ 0, n = 1, 2, 3,..., 6, when q n1 = 0, the antenna stops power supply, and the output power is 0), and at this time, after the heating time continues for t3, the oil production volume is V3, and therefore the energy-oil ratio δ3 = (q 11 +q 22 +q 32 +q 42 +q 52 +q 62 )t3 / V3. When (δ2-δ3) / δ2≥10% is satisfied, the values of q 11 , q 21 , q 31 , q 41 , q 51 , and q 61 no longer change, and the remaining heavy oil resources in the reservoir inside the area where the downhole radio frequency heating equipment is located are continuously heated and exploited.

[0096] (4) The steps (3) are repeated m times, the energy-oil ratio is δ m+1 , and the process is repeated until (δ m -δ m+1 ) / δ mIf less than 0.1, stop heating and oil production in the area where the downhole radio frequency heating equipment is located.

[0097] (5) Move the radio frequency heating equipment along the shaft to a new reservoir area, and reciprocate to heat and develop according to steps (1), (2), (3) and (4).

[0098] Based on the above scheme, the downhole radio frequency heating equipment based on antenna array distribution is composed of antenna 1 (multiple), shell cylinder 2, centralizer 3 and power supply wire 4. The shell cylinder 2 is internally provided with multiple linear antennas, which protect the antenna 1 and are uniformly distributed in the shell cylinder 2 along the radial direction. The centralizer 3 is provided with multiple holes, and the linear antennas are inserted into the holes to fix the linear antennas; the temperature sensor power supply wire 6 supplies power to the temperature sensor 5, and the temperature sensor 5 is installed in the inner hole of the centralizer 3; the antenna power supply wire 4 supplies power to each linear antenna, and the function of the pipe string 7 is not only to send in the antenna power supply wire 4 and the temperature sensor power supply wire 6, but also to send the entire radio frequency heating equipment into the shaft 8 (refer to Figure 4 ).

[0099] In addition, the attached Figure 5 includes: a reservoir area 9-1 containing more heavy oil and a multi-antenna heating control direction 9-2.

[0100] It should be noted that the above downhole radio frequency heating equipment uses existing technology, and its specific structure will not be described here.

[0101] The antenna array distribution downhole radio frequency heating equipment provided by the application can improve the electric power required for heating the reservoir, has higher thermal energy output and heating distance than single-antenna heating, controls the heating direction, realizes efficient heating, forms a downhole radio frequency heating heavy oil control method based on antenna array distribution to control the heating of the downhole heavy oil reservoir, realizes the lowest power consumption after the electric energy required for heating the heavy oil reservoir is sufficient to heat the reservoir, further enhances the energy saving and economic performance of the radio frequency heating heavy oil technology, and realizes the development, upgrading and efficiency improvement of heavy oil in the oil and gas field.

[0102] The effects of the application are as follows:

[0103] (1) The antenna array distribution radio frequency heating equipment improves the output power of heating, and improves the heavy oil heating area and the exploitation efficiency;

[0104] (2) By controlling the output power of each antenna, the heating direction is controlled and low-energy heating is realized, and the energy saving advantage of the technology is enhanced;

[0105] (3) The antenna array-based radio frequency heating technology, equipment, process and method provide a new idea for heavy oil development in China, and help to improve the quality and efficiency of heavy oil development in China.

[0106] It should be noted that each electronic component involved in the present application adopts the prior art, and each component is electrically connected with the controller, and the control circuit between the controller and each component is the prior art.

[0107] It is apparent to those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and can be realized in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the elements of the claims. Any reference signs in the claims should not be considered as limiting the claims to which they relate.

[0108] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be combined appropriately to form other embodiments that those skilled in the art can understand.

[0109] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling downhole radio frequency heating of heavy oil based on antenna array distribution, characterized in that, The specific steps include the following: S1: During the initial heating, multiple antennas (1) heat the heavy oil reservoir (9) in the area with the same output power q. After the heating time lasts for t1, the oil production volume is V1 and the oil-energy ratio is δ1. S2: With prolonged heating and the extraction of more heavy oil to the surface, the energy-to-oil ratio increases, leading to increased energy consumption. At this point, the output power of multiple antennas (1) differs. n , sequentially turn on some antennas (1) to heat the heavy oil reservoir (9) in the area. After the heating time lasts for t2, the oil production volume is V2 and the oil-energy ratio is δ2. Select a δ2 that is less than δ1, and take the antenna (1) and power corresponding to the smallest δ2 from the selected δ2 to heat the heavy oil reservoir (9) in the area. S3: Heating continues. When the energy-to-oil ratio increases again (>δ2), repeat step S2. Repeat this process m times until the energy-to-oil ratio is δ. m+1 until (δ) m -δ m+1 ) / δ m If the value is less than 0.1, it indicates that oil extraction in this area is complete, and heating and oil extraction in the area where the downhole radio frequency heating equipment is located will be stopped.

2. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to claim 1, characterized in that: The output power q of the multiple antennas (1) in S1, the heating time t1, the oil extraction volume V1, and the oil-energy ratio δ1 satisfy the following formula: δ1=(q·n)t1 / V1; Among them, the unit of antenna (1) output power q is W, the unit of heating time t1 is h, and the unit of oil extraction volume V1 is m. 3 The unit of δ1 is J / m 3 , where n is the number of antennas (1).

3. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to claim 1, characterized in that: The output power q of the multiple antennas (1) in S2 n The heating time duration t2, the oil production volume V2, and the energy-to-oil ratio δ2 satisfy the following formula: δ2=(q1+q2+q3+q4+q5+......+q n t2 / V2; Where n is the number of antennas (1).

4. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that, The following relationship exists between δ1 in S1 and δ2 in S2: (δ1-δ2) / δ1≥10%.

5. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that, S3 is followed by S4: The radio frequency heating equipment is moved along the wellbore axis to a new reservoir area, and oil and gas heating development is carried out by repeating the operations described in S1, S2 and S3.

6. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that: In S2, multiple antennas (1) that are turned on each time are arranged in a continuous manner.

7. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that: The number of antennas (1) in S1 and S2 is six.

8. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that: The multiple antennas (1) in S1 and S2 are evenly spaced in a circular pattern.

9. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that: The multiple antennas (1) in S1 and S2 are linear antennas.

10. The downhole radio frequency heating heavy oil control method based on antenna array distribution according to any one of claims 1-3, characterized in that: In S1, multiple antennas (1) are lowered into the working well by a tubing string.

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