CN104453805B - Method for quickly starting heavy oil reservoir steam assisted gravity drainage - Google Patents

Abstract

The invention relates to a method for quickly starting steam-assisted gravity drainage of heavy oil reservoirs, which comprises the following steps: (1) high-power electric heating of steam injection wells and production wells; (2) long oil pipes and Simultaneously inject solvent into the short tubing; (3) inject solvent and steam mixed fluid into the long tubing and short tubing of the steam injection well at the same time, inject the solvent and steam mixed fluid into the long tubing of the production well, and drain the liquid from the short tubing of the production well; (4) ) Turn off the electric heating, inject pure steam into the long oil pipe and the short oil pipe of the steam injection well at the same time, and drain the long oil pipe and the short oil pipe of the production well at the same time. The inventive method takes more than 2/3 less time than the conventional preheating start-up method, thereby greatly improving the utilization rate of heat energy, realizing fast preheating start-up of SAGD, and accelerating the production speed of SAGD. In addition, through rapid solvent expansion and super-fracture pressure injection, a uniform oil drainage channel can be established to achieve the purpose of increasing production and recovery.

Description

A method for rapid start-up of steam-assisted gravity drainage in heavy oil reservoirs

technical field

The invention relates to a method for exploiting heavy oil reservoirs in oil fields, in particular to a quick start method for steam-assisted gravity drainage (SAGD) of heavy oil reservoirs.

Background technique

Steam-assisted gravity drainage technology (abbreviation: SAGD) was invented by Canada's Buter in 1978, and has been successfully applied in heavy oil reservoirs in Canada's oil sands mining area, my country's Liaohe Oilfield, Xinjiang Oilfield and other places. The principle is to deploy upper and lower horizontal well pairs in the same oil layer, and inject high-dryness steam into the upper steam injection well. The steam is much denser than crude oil, and the steam overlaps upwards in the formation to form a steam cavity. With the continuous injection of steam , the steam chamber continuously expands upwards and sideways, and exchanges heat with the crude oil in the oil layer. The viscosity of the heated crude oil is reduced, and the condensed water flows downward under the action of gravity, and is extracted from the horizontal production well in the lower part of the oil layer.

Relevant literature points out that SAGD mining is divided into two stages: SAGD start-up stage and SAGD production stage. In the SAGD start-up stage, there are usually two methods for SAGD start-up: huff and puff preheat start and steam injection cycle preheat start. Among them, huff and puff preheat start has high injection pressure and high temperature, which is easy to cause damage to the completion wellbore structure. The preheating of the steam injection cycle starts with uniform heating and stable start. It is generally divided into three steps: (1) Steam circulates in the two wells, and the reservoir mainly transfers heat through heat conduction; (2) The interwell pressure difference is formed between the two wells, and the injection The pressure of the steam well is higher than that of the production well, so that the crude oil between the wells flows to the production well, preparing for the transition to full SAGD production; (3) The annulus of the upper steam injection well stops draining liquid, and the lower production well stops steam injection, and turns into full SAGD production. The SAGD production stage.

Wells must be thermally cycled prior to SAGD production. The stage from the injection of steam into production wells and steam injection wells to the beginning of conversion to SAGD production is called the start-up stage, or the preheating stage. The goal of the preheating stage is to achieve uniform heating of the oil layer in the shortest time, to make the steam injection well and the production well evenly heated and connected, and to establish an oil drainage channel between the steam injection well and the production well.

For conventional steam injection cycle preheating, a long oil pipe extending into the toe of the horizontal section and a short oil pipe extending into the heel of the horizontal section are lowered into the wellbore of the steam injection well and the production well. The long tubing in the wellbore of the lower production well is injected, and then produced from the short tubing in the upper steam injection well and the lower production well respectively. Relying on the heat conduction, heat convection, and heat radiation between the injected steam and the oil layer to heat the oil layer between the steam injection well and the production well, reduce the viscosity of the crude oil to below 150 centipoise, and make it have better fluidity After entering the SAGD production stage, the crude oil in the oil layer between the steam injection well and the production well can flow smoothly and form an oil drainage channel, so that the steam chamber can be continuously expanded, and the crude oil can be continuously drained and produced.

However, the conventional steam injection cycle preheating method is affected by the thermophysical parameters such as thermal conductivity and thermal diffusivity of the reservoir. The viscosity of crude oil in the oil layer can only reach below 150 centipoise. Since the cycle preheating requires that the steam discharged from the short tubing has a dryness of at least 10%, it is required that the wellhead where the steam is injected has a high dryness, usually higher than 80%, especially for deep oil reservoirs, the dryness of the steam along the way The heat loss per degree is greater, and the dryness of the wellhead steam usually needs to reach 100%. Therefore, a large amount of steam and a large amount of heat energy will be consumed in the cycle preheating stage, resulting in too long preheating time of SAGD, high initial mining cost and slow production rate.

Therefore, relying on years of experience and practice in related industries, the inventor proposes a quick start-up method for steam-assisted gravity drainage of heavy oil reservoirs to overcome the defects of the prior art.

Contents of the invention

The object of the present invention is to provide a quick start method for steam-assisted gravity drainage of heavy oil reservoirs, so as to realize the reduction of energy consumption and quick start.

The object of the present invention is achieved like this, a kind of heavy oil reservoir steam-assisted gravity drainage quick-start method, this method at least comprises the following steps:

(1) Electric heating of steam injection wells and production wells;

(2) Inject solvent into the steam injection well and the production well long tubing and short tubing at the same time;

(3) Simultaneously inject the mixed fluid of solvent and steam into the long tubing and short tubing of the steam injection well, inject the mixed fluid of solvent and steam into the long tubing of the production well, and drain the liquid from the short tubing of the production well;

(4) Turn off the electric heating, inject pure steam into the long oil pipe and short oil pipe of the steam injection well at the same time, and drain the long oil pipe and short oil pipe of the production well at the same time.

In a preferred embodiment of the present invention, before step (1) is implemented, a long oil pipe extending into the toe of the horizontal section is lowered into the wellbore of the steam injection well and the production well, and the other is inserted into the heel of the horizontal section. and a short oil pipe parallel to the long oil pipe, an electric heating pipe, and a thermocouple temperature monitoring pipe.

In a preferred embodiment of the present invention, in step (1), resistance heating is used, the maximum resistance power per meter of horizontal section length is 1000-2000KW, and the maximum temperature is the saturated steam temperature corresponding to the pressure of the oil reservoir. The control power can be flexibly adjusted to control the maximum heating temperature.

In a preferred embodiment of the present invention, in step (1), electromagnetic and microwave heating are used.

In a preferred embodiment of the present invention, the heating time in step (1) is 5-10 days.

In a preferred embodiment of the present invention, in step (2), the solvent type is an alkane solvent with carbon numbers ranging from 5 to 20, and the solvent temperature is the saturated steam temperature under the pressure of the oil layer.

In a preferred embodiment of the present invention, in step (2), the selected solvent is the solvent with the highest viscosity-reducing range for crude oil under the same solvent mole fraction under the oil layer pressure and the saturated steam temperature corresponding to the pressure or solvent systems.

In a preferred embodiment of the present invention, in step (2), the total injection rate of single well solvent is 100-500 tons/day, the injection rate of long tubing and short tubing is 1:1, and the highest injection pressure exceeds oil layer fracture The pressure is 0.3-0.5MPa, and the injection time is 1-3 days.

In a preferred embodiment of the present invention, in step (3), the total injection rate of the steam injection well is 100-200 tons/day, the injection mass velocity ratio of the long tubing and the short tubing is 1:1, and the long tubing injection of the production well is 1:1. The speed is 100 tons/day, and the short oil pipe of the production well is drained, and the liquid discharge speed of the short oil pipe is 100-200 tons/day.

In a preferred embodiment of the present invention, in step (3), the mass ratio of the solvent to the steam in the mixed fluid is three levels, and decreases step by step with the injection time; specifically, the first 5-10 day, the mass ratio of solvent to steam is 2:1; in the middle 5-10 days, the mass ratio of solvent to steam is 1:1; in the last 5-10 days, the mass ratio of solvent to steam is 1:2; the step time is 15-30 days;

In a preferred embodiment of the present invention, in step (3), the injection pressure of the steam injection well decreases linearly from 0.3-0.5 MPa higher than the fracture pressure of the oil layer to 0.3-0.5 MPa higher than the original reservoir pressure; The drainage pressure gradually decreases linearly from the fracture pressure of the oil layer to the original reservoir pressure; the pressure difference between the injection and production wells is always maintained at 0.3-0.5MPa.

In a preferred embodiment of the present invention, in step (4), when the bottom hole dryness of the injected steam in the SAGD production stage is less than 50%, the electric heating in the steam injection well is turned on in good time to heat in situ and improve the steam dryness .

From the above, the steam-assisted gravity drainage quick-start method for heavy oil reservoirs of the present invention first adopts downhole resistance/electromagnetic/microwave heating to quickly preheat the oil layer about 1 meter near the wellbore, and then injects synchronously into the steam injection well and the production well The liquid solvent realizes rapid capacity expansion and solvent rapid oil dissolution, reduces the viscosity of crude oil near the wellbore, then injects the mixed fluid of solvent and steam at a certain ratio, and gradually adjusts the ratio of solvent and steam to quickly establish oil drainage channels between injection and production wells, and finally injects The steam wells are completely changed to steam injection, and the production wells are completely changed to production, thus transferring to the SAGD production stage.

The steam-assisted gravity drainage quick start method for heavy oil reservoirs of the present invention has the following technical effects:

(1) In the SAGD start-up method provided by the present invention, first, a high-power electric heater is used to rapidly raise the temperature of the oil layer within 1 meter near the wellbore to the saturated steam temperature. This process only takes 5-10 days; while conventional steam injection It takes 30-50 days to preheat the oil layer within 1 meter near the wellbore by circulating preheating;

(2) After the temperature is raised near the wellbore, hot solvent is injected into the steam injection well and the production well at a high speed higher than the fracture pressure of the oil layer at the same time. Since the temperature near the wellbore is already high, the solvent quickly enters the oil layer near the wellbore to further dissolve the oil and reduce the viscosity. The micro-fractures generated by the super-fracture pressure enter the middle of the oil layer between the steam injection well and the production well, increase the range of oil dissolution and viscosity reduction, and establish the pressure connection between the steam injection well and the production well;

(3) After the solvent breaks through the oil layer between the steam injection well and the production well along the fracture, the solvent and steam composite fluid (mixed fluid) is continuously injected into the steam injection well, while the production well adopts cyclic injection and production. The injection pressure of the steam injection well is related to the production The drainage pressure of the well decreases step by step synchronously, and the pressure difference remains constant, which is conducive to stabilizing the pressure in the wellbore of the production well, ensuring that the fluid injected from the steam injection well enters the production well evenly along the horizontal section, realizing the uniform establishment of the oil drainage channel, and preventing single At the same time, since steam has a good dissolution effect on the mudstone/sand-shale interlayer or low-permeability layer between the steam injection well and the production well, increasing the proportion of steam step by step can dissolve the level of the steam injection well and the production well. The low-permeability interlayer section between the sections improves the overall oil drainage capacity and the uniformity of oil drainage. The presence of solvent can further accelerate the viscosity reduction, and achieve the purpose of rapidly reducing the viscosity of crude oil in the oil layer between the steam injection well and the production well to 150 centipoise;

(4) Compared with the conventional SAGD cycle preheating start-up method, the above-mentioned method proposed by the present invention only needs 21-43 days for the overall preheating time, which is more than 2/3 time less than the conventional preheating start-up method, thereby greatly improving the Thermal energy utilization can realize rapid warm-up and start-up of SAGD, and accelerate the production speed of SAGD; in addition, through rapid solvent expansion and super-fracture pressure injection, a uniform oil drainage channel can be established to achieve the purpose of increasing production and recovery.

Description of drawings

The following drawings are only intended to illustrate and explain the present invention schematically, and do not limit the scope of the present invention.

in:

Fig. 1: is the schematic flow chart of the steam assisted gravity drainage (SAGD) quick start method of heavy oil reservoir of the present invention.

detailed description

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

As shown in Figure 1, the present invention proposes a quick start-up method for steam-assisted gravity drainage of heavy oil reservoirs. First, downhole electric heating is used to quickly preheat the oil layer near the wellbore, and then the steam injection well and the production well inject liquid solvent synchronously to realize rapid drainage. Expansion and solvent quickly dissolve oil, reduce the viscosity of crude oil near the wellbore, then inject a mixed fluid of solvent and steam at a certain ratio, and gradually adjust the ratio of solvent and steam, quickly establish oil drainage channels between injection and production wells, and finally steam injection wells are completely improved In order to inject steam, the production well is completely changed to production, thus transferring to the SAGD production stage;

Specifically, the method at least includes the following steps:

(1) Electric heating of steam injection wells and production wells;

(2) Inject solvent into the steam injection well and the production well long tubing and short tubing at the same time;

(3) Simultaneously inject the mixed fluid of solvent and steam into the long tubing and short tubing of the steam injection well, inject the mixed fluid of solvent and steam into the long tubing of the production well, and drain the liquid from the short tubing of the production well;

(4) Turn off the electric heating, inject pure steam into the long oil pipe and short oil pipe of the steam injection well at the same time, and drain the long oil pipe and short oil pipe of the production well at the same time.

The steam-assisted gravity drainage quick start-up method of the heavy oil reservoir of the present invention takes more than 2/3 less time than the conventional preheating start-up method, thereby greatly improving the utilization rate of heat energy, realizing the rapid preheating start-up of SAGD, and accelerating the production of SAGD speed; in addition, through rapid expansion of solvent and injection of super-fracture pressure, a uniform oil drainage channel can be established, which can increase production and recovery.

Embodiment one

This embodiment provides a method for quick start-up of SAGD in heavy oil reservoirs. First, a long oil pipe extending to the toe of the horizontal section is lowered into the wellbore of the SAGD steam injection well and the production well, and the other is inserted into the heel of the horizontal section. A short oil pipe parallel to the long oil pipe, an electric heating pipe, and a thermocouple temperature monitoring pipe.

The SAGD quick start method of the heavy oil reservoir comprises the following specific steps:

(1) Carry out high-power electric heating for steam injection wells and production wells, adopt resistance heating, the highest resistance power is 1000KW/unit horizontal section length (m), and the highest temperature is the saturated steam temperature corresponding to the pressure of the oil layer, which can be flexibly adjusted on the ground Control the power, thereby controlling the maximum heating temperature, and the heating time is 10 days.

(2) Inject the solvent into the long and short oil pipes of the steam injection well and the production well at the same time. The solvent type is an alkane solvent with a carbon number of 5, and the solvent temperature is the saturated steam temperature under the pressure of the oil layer. The high temperature viscosity test results show that, The selected solvent is at the oil reservoir pressure and the saturated steam temperature corresponding to the pressure, and at the same mole fraction of the solvent, the solvent has the highest viscosity-reducing range for the crude oil; The injection rate of the tubing is 1:1, the maximum injection pressure is 0.3MPa higher than the fracture pressure of the reservoir, and the injection time is 3 days.

(3) Inject the mixed fluid of solvent and steam into the long tubing and short tubing of the steam injection well at the same time. The mixed fluid of solvent and steam is injected at an injection rate of 100 tons/day, and the short tubing of the production well is drained at a rate of 200 tons/day. The mass ratio of solvent to steam is three levels and decreases step by step; the step time is 15 days, specifically, in the first 5 days, the mass ratio of solvent to steam is 2:1; in the middle 5 days, the mass ratio of solvent to steam The ratio was 1:1; in the last 5 days, the mass ratio of solvent to steam was 1:2; the injection pressure of the steam injection wells gradually decreased from 0.3MPa higher than the fracture pressure of the reservoir to 0.3MPa higher than the original reservoir pressure; The hydraulic pressure gradually decreases from the fracture pressure of the oil layer to the original reservoir pressure; the pressure difference between the injection and production wells is always maintained at 0.3MPa.

(4) Turn off the electric heating, inject pure steam into the long tubing and short tubing of the steam injection well at the same time, drain the long tubing and short tubing of the production well at the same time, and enter the SAGD production stage.

Compared with the conventional steam injection cycle preheating start-up method for adjacent SAGD well pairs, the overall preheating time in this embodiment only needs 28 days, which is more than 2/3 less than the conventional preheating start-up method (conventional method: 150 days) , thus greatly improving the utilization rate of thermal energy, realizing rapid warm-up and start-up of SAGD, and accelerating the production speed of SAGD; in addition, through rapid solvent expansion and super-fracture pressure injection, a uniform oil drainage channel can be established to achieve increased production and recovery the goal of.

Embodiment two

The well pattern structure of the present embodiment is identical with embodiment one, and its difference is following specific steps:

(1) Carry out high-power electric heating for steam injection wells and production wells, adopt resistance heating, the highest resistance power is 1500KW/unit horizontal section length (m), and the highest temperature is the saturated steam temperature corresponding to the pressure of the oil layer, which can be flexibly adjusted on the ground Control the power, thereby controlling the maximum heating temperature, and the heating time is 7 days.

(2) Inject solvent into the long tubing and short tubing of the steam injection well and the production well at the same time. The solvent type is an alkane solvent with 10 carbon numbers. The solvent is selected to reduce the viscosity of the crude oil at the same solvent mole fraction under the reservoir pressure and the saturated steam temperature corresponding to the pressure; The injection rate is 1:1, the maximum injection pressure is 0.4MPa higher than the fracture pressure of the reservoir, and the injection time is 2 days.

(3) Inject the mixed fluid of solvent and steam into the long tubing and short tubing of the steam injection well at the same time. The mixed fluid of solvent and steam is injected at an injection rate of 100 tons/day, and the short tubing of the production well is drained at a rate of 150 tons/day. The mass ratio of solvent to steam is three levels and decreases step by step; the step time is 21 days, specifically, in the first 7 days, the mass ratio of solvent to steam is 2:1; in the middle 7 days, the mass ratio of solvent to steam The ratio was 1:1; in the last 7 days, the mass ratio of solvent to steam was 1:2; the injection pressure of the steam injection wells gradually decreased from 0.4MPa higher than the fracture pressure of the reservoir to 0.4MPa higher than the original reservoir pressure; The hydraulic pressure gradually decreases from the fracture pressure of the oil layer to the original reservoir pressure; the pressure difference between the injection and production wells is always maintained at 0.4MPa.

(4) Turn off the electric heating, inject pure steam into the long tubing and short tubing of the steam injection well at the same time, drain the long tubing and short tubing of the production well at the same time, and enter the SAGD production stage.

Compared with the conventional steam injection cycle preheating start-up method for adjacent SAGD well pairs, the overall preheating time in this embodiment only needs 30 days, which is more than 2/3 less than the conventional preheating start-up method (conventional method 150 days), In this way, the thermal energy utilization rate is greatly improved, and the rapid warm-up and start-up of SAGD can be realized, and the production speed of SAGD can be accelerated; in addition, through the rapid expansion of solvent and super-fracture pressure injection, a uniform oil drainage channel can be established to realize the combination of increasing production and recovery Purpose.

Embodiment three

The well pattern structure of the present embodiment is identical with embodiment one, and its difference is following specific steps:

(1) Carry out high-power electric heating for steam injection wells and production wells, adopt resistance heating, the maximum resistance power is 2000KW/unit horizontal section length (m), and the maximum temperature is the saturated steam temperature corresponding to the pressure of the oil layer, which can be flexibly adjusted on the ground Control the power, thereby controlling the maximum heating temperature, and the heating time is 5 days.

(2) Inject solvent into the long tubing and short tubing of the steam injection well and the production well at the same time. The solvent type is an alkane solvent with 20 carbons, and the solvent temperature is the saturated steam temperature under the pressure of the reservoir. The high temperature viscosity test results show that The solvent is selected to reduce the viscosity of the crude oil at the same solvent mole fraction under the reservoir pressure and the saturated steam temperature corresponding to the pressure; The injection rate is 1:1, the maximum injection pressure is 0.5MPa higher than the fracture pressure of the reservoir, and the injection time is 1 day.

(3) Inject the mixed fluid of solvent and steam into the long oil pipe and short oil pipe of the steam injection well at the same time, the total injection rate of a single well is 100 tons/day, and the injection ratio of the long oil pipe and the short oil pipe is 1:1; The mixed fluid of solvent and steam is injected at an injection rate of 100 tons/day, and the short tubing of the production well is drained at a rate of 100 tons/day. The mass ratio of solvent to steam is three levels and decreases step by step; the step time is 30 days, specifically, in the first 10 days, the mass ratio of solvent to steam is 2:1; in the middle 10 days, the mass ratio of solvent to steam The ratio is 1:1; in the last 10 days, the mass ratio of solvent to steam is 1:2; the injection pressure of steam injection wells gradually drops from 0.5MPa higher than the fracture pressure of the reservoir to 0.5MPa higher than the original reservoir pressure; The hydraulic pressure gradually decreases from the fracture pressure of the oil layer to the original reservoir pressure; the pressure difference between the injection and production wells is always maintained at 0.5MPa.

(4) Turn off the electric heating, inject pure steam into the long tubing and short tubing of the steam injection well at the same time, drain the long tubing and short tubing of the production well at the same time, and enter the SAGD production stage.

Compared with the conventional steam injection cycle preheating start-up method for adjacent SAGD well pairs, the overall preheating time in this embodiment only needs 36 days, which is more than 2/3 less than the conventional preheating start-up method (conventional method 150 days), In this way, the thermal energy utilization rate is greatly improved, and the rapid warm-up and start-up of SAGD can be realized, and the production speed of SAGD can be accelerated; in addition, through the rapid expansion of solvent and super-fracture pressure injection, a uniform oil drainage channel can be established to realize the combination of increasing production and recovery Purpose.

The above descriptions are only illustrative specific implementations of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the protection scope of the present invention.

Claims (10)

1. a kind of heavy crude reservoir SAGD quick start method, the method is at least comprised the following steps：

(1) steam injection well and producing well electrical heating, maximum temperature is the corresponding saturated-steam temperature of the formation pressure；

(2) to injecting solvent simultaneously in steam injection well and producing well oil pipe long and short oil pipe；Type of solvent is alkane of the carbon number from 5-20 Hydrocarbon solvent, solvent temperature is the saturated-steam temperature under the formation pressure；The total injection rate of individual well solvent be 100-500 tons/ My god；Injection pressure highest exceedes oil breakdown pressure 0.3-0.5MPa；

(3) to the fluid-mixing for injecting solvent and steam in steam injection well oil pipe long and short oil pipe simultaneously, in producing well oil pipe long The fluid-mixing of injection solvent and steam, producing well short oil pipe discharge opeing；The mass ratio of solvent and steam in the fluid-mixing It is three-level, and declines step by step with injection length；Specifically, at first 5-10 days, solvent and quality of steam ratio are 2：1；In centre 5-10 days, solvent and quality of steam ratio were 1：1；At last 5-10 days, solvent and quality of steam ratio were 1：2；The step Time is 15-30 days；Steam injection well inject pressure from higher than oil breakdown pressure 0.3-0.5MPa it is linear gradually decrease to be higher than Initial reservoir pressure 0.3-0.5MPa；

(4) electrical heating is closed, to injecting pure steam, producing well oil pipe long and short oil pipe in steam injection well oil pipe long and short oil pipe simultaneously Discharge opeing simultaneously.

2. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (1) before implementing, an oil pipe long for stretching to horizontal segment tiptoe is entered down in steam injection well and production well shaft, one stretches to water Flat section heel and the short oil pipe being parallel to each other with oil pipe long, an electric heating tube, and an electric thermo-couple temperature monitoring pipe.

3. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (1) in, using resistance heating, every meter of maximum resistance power of horizontal section length is 1000-2000KW, is flexibly adjusted by ground Section control power, so as to control maximum heating temperature.

4. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (1) in, using electromagnetism or heating using microwave.

5. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：Step (1) heat time in is 5-10 days.

6. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (2) in, selected solvent is under formation pressure and the corresponding saturated-steam temperature of the pressure, in same solvent molar fraction Under, to reducing crude oil viscosity amplitude highest solvent.

7. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (2) in, oil pipe long is 1 with short oil pipe injection rate：1, injection length is 1-3 days.

8. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (3) in, the total injection rate 100-200 ton days of steam injection well, oil pipe long is 1 with short oil pipe implantation quality speed proportional：1, production Well oil pipe injection rate long is 100 ton days, and producing well short oil pipe discharge opeing, short oil pipe drain age velocity is 100-200 ton days.

9. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step (3) in, lines of producing wells hydraulic coupling linearly gradually decreases to initial reservoir pressure from oil breakdown pressure；Pressure difference is all the time between injection-production well Remain 0.3-0.5MPa.

10. heavy crude reservoir SAGD quick start method as claimed in claim 1, it is characterised in that：In step Suddenly in (4), when being less than 50% for the shaft bottom mass dryness fraction that the SAGD production phases inject steam, electrical heating in steam injection well is opened in good time, In Situ Heating simultaneously improves steam quality.