RU2029069C1 - Device for well heating and method for maintenance of well heating conditions - Google Patents

Abstract

FIELD: oil producing industry. SUBSTANCE: installed in well pipes is heater in form of metal cylinder consisting of upper and lower parts of heated surfaces different in cross-section. Cylinder parts are electrically connected and the cylinder itself is connected with power source. Parameters of relations of heater parts lengths, sectional areas and heated surface areas are interrelated. Heating conditions are controlled by comparing temperatures of fluid heated in well and paraffin melting, well pipe and heated surface. Values of operating current are established as referred to minimum current value required for prevention of paraffin settling within preset limits. EFFECT: higher efficiency. 7 cl, 2 dwg, 1 tbl

Description

 The invention relates to the field of the oil industry and can be used to equip wells and maintain optimal thermal conditions in them in order to eliminate paraffin-hydrate formations.

 A device is known for maintaining the thermal regime of a well at a warning level in it of paraffin hydrate formation, containing a geophysical cable with a core of seven multiwire conductive cores, a pillow for armor in the form of a winding of polyethylene terephthalate tape, armor of steel round wires connected to a three-phase power source [1].

 A disadvantage of the known device is the low level of released electric power, insufficient to prevent the formation of paraffin deposits, especially in cases of high content of paraffin fractions in oil (more than 10%).

 Known temperature-controlled well, method and means of maintaining its thermal regime, containing a power source, downhole pipes, inside which is located a heating device [2] - prototype.

 A known method of maintaining thermal conditions in a well, including introducing into it a heating metal surface and a conductive bus, passing electric current through them and controlling the supplied electric power until a predetermined thermal regime is established in the downhole pipes [2], is a prototype.

 The lack of prototypes is the failure to use all the possibilities of thermal heating in wells to ensure maximum productivity and optimize the process of oil and gas production.

 The purpose of the invention is the resumption of oil and gas production in wells that have previously been decommissioned due to the formation of hydro-paraffin plugs, the exclusion of the possibility of the formation of new plugs throughout the operation, the optimization of oil and gas production, and the increase in oil and gas production productivity in wells.

≅ 2,0
Цилиндр составлен из двух электрически соединенных между собой верхней и нижней частей неодинакового сечения нагреваемой металлической поверхности, охватывающей вместе с изолятором электропроводящую шину, электрически соединенных между собой в нижней части цилиндра таким образом, что в каждой из плоскостей поперечного сечения внутренний периметр Р₁ скважинной трубы взаимосвязан с наружным периметром Р₂верхней части нагреваемой металлической поверхности с отношением в пределах:
0,01 ≅

≅ 1,0
Площадь S₁ нагреваемой металлической поверхности выбрана по отношению к площади S₂ скважинных труб в пределах:
0,001 ≅

≅ 1,0
Площадь сечения S₃ нижней части нагреваемой металлической поверхности на ее длине L₃, выбранной по отношению к общей длине L₁термонагревательного устройства в пределах:
1,0 ≅

≅ 2,0, взаимосвязана с величиной S₄ площади поперечного сечения верхней части нагреваемой металлической поверхности в соотношении:
0,15 ≅

≅ 0,6
Скважина снабжена дополнительным отделяемым автономным блоком управления ее тепловым режимом, соединенным с источником питания, и автономным отделяемым стабилизатором тока, соединенным с источником питания, нагреваемой металлической поверхностью и блоком управления.Achieving the goal is ensured in a thermostatic well containing a power source, downhole pipes, inside of which there is a thermal heating device, consisting of a heater and electrical wiring in that the heater is made in the form of a metal cylinder, the length L _{1 of} which is selected with respect to the length L _{2 of the} downhole pipe within
1.01 ≅

≅ 2.0
The cylinder is composed of two upper and lower parts of an unequal cross section of a heated metal surface electrically connected to each other, covering an electrically conductive tire together with an insulator, electrically connected to each other in the lower part of the cylinder so that in each of the cross-section planes the inner perimeter P _{1 of the} borehole is interconnected with the outer perimeter P _{2 of the} upper part of the heated metal surface with a ratio within:
0,01 ≅

≅ 1,0
The area S _{1 of the} heated metal surface is selected with respect to the area S _{2 of the} downhole pipes within:
0,001 ≅

≅ 1,0
The cross-sectional area S _{3 of the} lower part of the heated metal surface along its length L ₃ , selected in relation to the total length L _{1 of the} heating device within:
1,0 ≅

≅ 2.0, is interconnected with the value S _{4 of} the cross-sectional area of the upper part of the heated metal surface in the ratio:
0.15 ≅

≅ 0.6
The well is equipped with an additional detachable autonomous control unit for its thermal regime connected to a power source, and an autonomous detachable current stabilizer connected to a power source heated by a metal surface and a control unit.

≅ 1,5.The goal is also achieved using a method of maintaining thermal conditions in a well, including introducing a heated metal surface and a conductive busbar into it, passing electric current through them and controlling the supplied electric power until a specified thermal regime is established in the downhole pipes. The temperature t ₁ heated in the well of a liquid or gas is maintained with respect to the melting temperature t ₂ of paraffin in the range:
1.01 ≅

≅ 1.5.

≅ 1,7, где С - теплоемкость жидкости и/или газа;
а - экспериментальный коэффициент, определяемый конструктивными особенностями нагреваемой металлической поверхности, теплопотерями и т.д.;
а=0,2÷0,35.The quantity Q of electric energy supplied per unit time, in relation to the amount m of the liquid or gas heated by it, is selected within the limits of:
0.15 ≅

≅ 1.7, where C is the heat capacity of the liquid and / or gas;
a - experimental coefficient determined by the design features of the heated metal surface, heat loss, etc .;
a = 0.2 ÷ 0.35.

≅ 0,55, устанавливая значение рабочего тока J_раб, нагревающего металлическую поверхность по отношению к минимальному току J_min, необходимому для предотвращения осаждения парафина в пределах:
1,0 ≅

≅ 1,4.The temperature t _{3 of the} downhole pipe is maintained with respect to temperature t _{4 of the} heated metal surface within:
0,01 ≅

≅ 0.55, setting the value of the operating current J _slave heating the metal surface with respect to the minimum current J _min necessary to prevent the deposition of paraffin within:
1,0 ≅

≅ 1.4.

 In FIG. 1 shows a temperature controlled well; in FIG. 2 - control unit thermal regime of the well.

≅ 2,0.The temperature-controlled well contains a power source 1, downhole pipes 2, inside of which there is a heating device 3, consisting of a heater 4 and electrical wiring 5. The heating device 3 is made in the form of a metal cylinder 4, of variable cross-section (cable), the length L _{1 of} which is selected with respect to the length L _{2 of the} downhole pipe 2 within:
1.01≅

≅ 2.0.

 Thus, the cylinder 4 is composed of two electrically interconnected upper 6 and lower 7 parts of a different section of the heated metal surface. The metal surface 4 covers the electrically conductive bus 5 together with its insulator and is electrically connected to it in the lower part 8. The metal surface 4 can also be electrically insulated with a material with good thermal conductivity, if necessary. The armor of the thermal heating device 3 can be used as a heated metal surface 4.

≅ 1.In each of the planes of the cross-section of the thermostatic well, the inner perimeter P _{1 of the} downhole pipe 2 is interconnected with the outer perimeter P _{2 of the} upper part 6 of the heated metal surface 4 by a ratio within:
0,01≅

≅ 1.

≅ 1,0
Вышеприведенные математические соотношения охватывают практически все возможные варианты конструктивных особенностей выполнения основных узлов (элементов) терморегулируемой скважины.The area S _{1 of} both parts 6 and 7 of the heated metal surface is selected with respect to the surface area S _{2 of the} surface of the downhole pipes within:
0,001 ≅

≅ 1,0
The above mathematical relationships cover almost all possible options for the design features of the main nodes (elements) of a temperature-controlled well.

≅ 2,0 взаимосвязана с величиной S₄ площади поперечного сечения верхней части в нагреваемой металлической поверхности в соотношении:
0,15 ≅

≅ 0,6.The cross-sectional area S _{3 of the} lower part 7 of the heated metal surface along its length L ₃ (Fig. 1), selected with respect to the total length L _{1 of the} heated metal surface, which practically determines the length of the thermal heating device 3 within:
1,0 ≅

≅ 2.0 is interconnected with the value S _{4 of} the cross-sectional area of the upper part in the heated metal surface in the ratio:
0.15 ≅

≅ 0.6.

For the sake of generality of the constructive solution, it should be noted that the areas S ₃ and S ₄ that are different from each other do not have to be strictly identical along the entire length of the upper and lower 7 parts of the heated metal surface, however, their ratio should correspond to the above expression.

 The well is equipped with an additional detachable autonomous control unit 9 for controlling its thermal regime connected to a power source 1 and an autonomous detachable current stabilizer 10 connected to a power source 1, block 9 and a heated metal surface. Optimum embodiments of block 9 and stabilizer 10 will be described below.

≅ 1,5
Количество электрической энергии Q, подаваемой в единицу времени по отношению к количеству m нагреваемой ею жидкости или газа, выбирают в пределах:
0,15 ≅

≅ 1,7, где с - теплоемкость жидкости и/или газа;
а - экспериментальный коэффициент, определяемый конструктивными особенностями нагреваемой металлической поверхности, теплопотерями и т.д., а= 0,2÷0,35.A method of maintaining thermal conditions in the well, reflecting the operation of the proposed device, is as follows. The temperature t _{1 of the} fluid or gas heated in the well is maintained with respect to the paraffin melting temperature t ₂ within:
1.01 ≅

≅ 1,5
The amount of electric energy Q supplied per unit time with respect to the amount m of the liquid or gas heated by it is selected within the limits of:
0.15 ≅

≅ 1.7, where c is the heat capacity of the liquid and / or gas;
a - experimental coefficient determined by the design features of the heated metal surface, heat loss, etc., a = 0.2 ÷ 0.35.

≅ 0,55.The temperature t _{3 of the} borehole pipe is maintained not lower than temperature t ₂ and with respect to temperature t _{4 of the} heated metal surface within:
0,01 ≅

≅ 0.55.

≅ 1,4
В целях оптимизации необходимых условий работы терморегулируемой скважины и ее теплового режима целесообразно использование блока 9 управления тепловым режимом и стабилизатора 10 тока. В блоке 9 управления тепловым режимом терморегулируемой скважины установлены датчики 11 и 12 контроля регулируемых параметров и исполнительные узлы 13 и 14, соединенные цепью 15 обратной связи. Отличительными особенностями блока 9 являются установка датчика 11 минимально допустимого значения объема подачи жидкости (газа) из скважины и датчика 12 максимально допустимого значения температуры жидкости (газа). Датчик 11 через узел 13 включения электронагрева скважины соединен с источником 1 электропитания. Датчик 12 через узел 14 выключения электронагрева скважины подключен к источнику 1 ее электропитания.To ensure this mode, the value of the operating current J _slave heating a metal surface with respect to the minimum current J _min necessary to prevent the deposition of paraffin (paraffin hydrate deposits), within:
1,0 ≅

≅ 1.4
In order to optimize the necessary operating conditions of the thermostatic well and its thermal regime, it is advisable to use the thermal management unit 9 and the current stabilizer 10. In block 9 for controlling the thermal regime of the thermoregulated well, sensors 11 and 12 for controlling adjustable parameters and actuating units 13 and 14 are connected by a feedback circuit 15. Distinctive features of block 9 are the installation of the sensor 11 of the minimum allowable value of the volume of fluid supply (gas) from the well and the sensor 12 of the maximum allowable temperature of the liquid (gas). The sensor 11 through the node 13 enable electric heating wells is connected to a power source 1. The sensor 12 through the node 14 off the electric heating of the well is connected to the source 1 of its power supply.

≅ 0,99
Выключение электронагрева скважины в целях экономии электроэнергии производят при достижении максимальной температуры t_maх нагреваемой жидкости и/или газа значения, которое по отношению к их номинальной температуре t_ном выбирают в пределах:
1,001 ≅

≅ 1,4
В качестве номинальных значений указанных параметров принимают их среднестатические значения, усредненные за некоторый, приемлемый для отчета промежуток времени (сутки, месяц, квартал и др.).The method for controlling the thermal regime of a temperature-controlled well by block 9 includes determining the extreme values of the above monitored parameters and controlling electric heating when the desired modes are reached. In practice this boils down to is that the inclusion of electrical heating wells produce with decreasing volume V _min fluid outlet and / or gas through the wellbore to a value that is relative to the nominal volume V _rated output is selected within:
0.85 ≅

≅ 0.99
Switching off a well’s electric heating in order to save electricity is carried out when the maximum temperature t _{max of the} heated liquid and / or gas is reached, which, in relation to their nominal temperature t _{nom, is} chosen within the limits of:
1,001 ≅

≅ 1.4
As the nominal values of these parameters take their average values averaged over a period of time acceptable for the report (day, month, quarter, etc.).

 The current stabilizer 10 of a temperature-controlled well containing a regulating unit 15 and a current meter 16 connected by a feedback circuit 17 is characterized in that it is further provided with serially connected detachable nodes 18 and 19 connected to a liquid and / or gas temperature sensor 12. These are the nodes, respectively: the burn current support (node 18) of the short circuit and the emergency circuit breaker (node 19) of the current when the supplied amount of burn electric power reaches a critical value, determined by the characteristics of the ignition of the heated liquid and / or gas. Feedback nodes 15 and 17 of blocks 9 and 10 are traditional for control and control systems and do not contain the features that distinguish them from the known ones.

≅ 1,1
При возникновении короткого замыкания в связи с трудностями извлечения из скважины термонагревательного устройства, его ремонта и нового погружения в скважину в стабилизаторе 10 предусмотрены для устранения прожига узлы 18 и 19. Для устранения короткого замыкания путем его прожига устанавливают стабилизируемый ток J_прож. прожига, существенно увеличенное значение которого поддерживают по отношению к J_стаб. в пределах:
2,0 ≅

≅ 15
Для обеспечения пожарной безопасности ток прожига отключают при достижении подаваемого количества энергии Э_прож прожига его критического значения Э_крит., при которой возможно воспламенение нефти (газа), в пределах:
0,7 ≅

≅ 1,0,
повторяя, таким образом, после охлаждения нагреваемой жидкости (газа) попытки прожига несколько раз до устранения места короткого замыкания. При этом легко устраняют наиболее часто возникающие короткие замыкания в виде точечных касаний или на небольших участках.The method of regulating the current in the stabilizer 10, includes measuring the current with the device 16 and maintaining it depending on the specified modes using the control unit 15 and is characterized in that the maximum deviation of the current Δ J from the value of the stabilized current value J _stab maintains
0.95 ≅

≅ 1,1
In the event of a short circuit due to difficulties in removing the thermal heating device from the well, repairing it, and re-immersing in the well in the stabilizer 10, nodes 18 and 19 are provided for eliminating burning. To stabilize the short circuit, a stabilized current J pierce is established by burning it _. burning, a significantly increased value of which is maintained in relation to J _stab . within:
2.0 ≅

≅ 15
To ensure fire safety, the burning current is turned off when reaching the supplied amount of energy E burning _through its critical value E _crit. in which ignition of oil (gas) is possible, within:
0.7 ≅

≅ 1.0,
repeating, thus, after cooling the heated liquid (gas), attempts to burn several times to eliminate the short circuit. In this case, the most frequently occurring short circuits in the form of point contacts or in small areas are easily eliminated.

 The described objects are interconnected by a single inventive concept, since all their essential features purposefully and inextricably ensure the achievement of the specified technical result - an increase in the productivity of oil and gas in wells. This is also proved by the following variants of examples of practical implementation of the claimed objects, in which it is inappropriate to repeat the essential features that are the same for each of the examples. Since the examples of the implementation of the claimed objects differ from each other only in the quantitative values of the parameters characterizing the essential features, it is advisable to summarize them in the following table.

 Evaluation of each of the options for the practical implementation of the declared facilities was carried out according to the parameter E (see table), which characterizes the ratio of the production rates of oil and / or gas in the proposed temperature-controlled well and the prototype well with their main characteristics as close as possible under operating conditions. As follows from the table, under optimal conditions for the practical implementation of a temperature-controlled well (option 1), the best productivity ratio was achieved (E = 1.5). The limiting values of the declared parameters were obtained by static processing of the results of experimental data, their analysis and generalization, based on the criterion of approximation of production productivity in the proposed well to production productivity in the well - prototype (lower limits, option 2, E = 1,0002 (upper limits, option 3, E = 1,0003).

 As follows from the table, going beyond the lower declared limits (option 4, E = 0.999) and beyond the upper limits (option 5, E = 0.998) makes it impossible to achieve the indicated technical result. Options 6, 7, 8 illustrate other combinations of the declared parameters, both being on and inside the declared limits with achieving a technical result (option 6, E = 1.1; option 8, E = 1.2), and when going beyond the declared limits and failure to achieve the specified technical result (option 7, E = 0.96).

 The totality of the declared facilities provides other advantages, among which it is advisable to note the resumption of oil and / or gas production in wells that had previously been decommissioned due to the formation of hydro-paraffin deposits, the exclusion of the possibility of the formation of new plugs throughout the life of the wells, and energy savings due to thermal regulation , optimization of the regime of oil and / or gas production, elimination of downtime of wells, improvement of the ecological climate by eliminating the spill of oil and paraffin during mechanical Coy wells purification, materials savings, etc.. d.

Claims (4)

 DEVICE FOR HEATING A WELL AND A METHOD OF MAINTAINING ITS HEAT MODE. 1. A device for heating a well, comprising a surface-mounted power source electrically connected to a heater located inside the borehole pipes, characterized in that it is provided with a self-contained thermal control unit connected to a power source and an autonomous current stabilizer connected to the heater, a source power supply and control unit, while the heater is made in the form of a composite metal cylinder of two electrically connected upper and lower parts of an uneven cross section agrevaemoy surface, the inner perimeter section P well pipe ₁ and outer perimeter ₂ P-sectional top of the cylinder are related by

the area S _{1 of the} heated surface and the area S _{2 of the} downhole pipes are related by the relation

the cross-sectional area S _{3 of the} lower part of the heated surface and the cross-sectional area S _{4 of the} upper part of the heated surface are related by

the length L _{3 of the} lower part of the heated surface and the total length L _{1 of the} cylinder are related by

and the length L _{1 of the} cylinder and the length L _{2 of the} downhole pipe are related by the ratio

2. The device according to claim 1, characterized in that the autonomous current stabilizer has series-connected blocks for monitoring the burn-off current of the emergency shutdown and a temperature sensor for the liquid (gas).  3. The device according to claim 1, characterized in that the stand-alone thermal mode control unit has sensors for monitoring the minimum allowable value of the liquid (gas) supply volume and the maximum allowable temperature value, the first being directly and the second through an emergency shutdown unit connected to a power source . 4. A method of maintaining a thermal regime in a well, including introducing into it a heater electrically connected to a power source, controlling the supplied electric power until a predetermined thermal regime is established in the well pipes, characterized in that the temperature t _{1 of the} fluid or gas heated in the well and the temperature t ₂ melting paraffin bonded by the ratio

the amount of electric energy Q supplied per unit time, with respect to the amount m of liquid or gas heated by it, is selected within

where C is the heat capacity of the liquid (gas);
a = 0.2-0.35 - experimental coefficient determined by the design features of the heated surface, heat loss, etc .;
wherein the temperature t _{3 of the} borehole pipe is maintained relative to the temperature t _{4 of the} heated surface within

set the operating current value I _{p and used} to heat the metal surface with respect to the minimum current I _{m i n,} necessary to prevent precipitation of the wax in the range

5. The method according to claim 4, characterized in that the supplied electric power is controlled by an autonomous thermal mode control unit by turning on the electric heating of the well while decreasing the volume V _{m i n} of liquid (gas) output through the well to a value that is relative to the nominal volume V _{n o m of} output choose within

and turning off the electric heating of the well when the maximum temperature of the heated fluid (gas) is reached to a value that, in relation to its nominal temperature, is selected within

6. A method according to claim 4, characterized in that the control of electric power supplied to perform autonomous current stabilizer, the maximum current deviation ΔI from the current values are stabilized value I _{s t a b} maintained within

when a short-circuit current is set to be stabilized burning I _{r o w n,} the value of which is maintained with respect to I _{s t a b} within

and burning off the current when the supply amount of the burning energy E _{n p o w} e its critical value _{for p and m} within

repeating after cooling the heated liquid (gas) attempts to burn to eliminate the short circuit.

Images