CN102230372A - Thermal recovery technology of multielement thermal fluid of thickened oil well - Google Patents

Abstract

The invention relates to a thermal recovery technology of a multielement thermal fluid of a thickened oil well, comprising the step of injecting a multielement thermal fluid and annular injection nitrogen into an oil layer together. The invention relates to a thermal recovery technology of a multielement thermal fluid of an offshore thickened oil well.

Description

A kind of heavy oil wells multielement hot fluid thermal recovery technology

Technical field

The present invention relates to a kind of heavy oil wells multielement hot fluid thermal recovery technology.

Background technology

China's viscous crude resource distribution is very wide, at present in the distant basin of pine, basin, Bohai Sea Gulf, accurate Ge Er basin, two connect the land heavy crude reservoir that One's name is legion has been found in 15 big-and-middle-sized oil basins such as basins and area; And viscous crude accounts for more than 60% in the marine oil field, and wherein the Bay areas heavy oil reserves accounts for about 80% of this zone gross reserves especially.At present the thickened oil recovery technology of using mainly contains oil recovery by heating technology (steam soak, steam flooding, SGAD, SAGP, FAST, hot water flooding, electromagnetism heating, combustion in situ etc.), goes out sand cooling and adopt technology, carbon dioxide huff and puff oil recovery technology and viscosity reducing oil recovery technique, and wherein steam soak, steam flooding are most widely used.Because steam soak thermal recovery technology is a kind of thermal recovery technology of step-down exploitation, along with the increase of the round of handling up, its exploitation effect is variation gradually, can not reach the purpose of economical and efficient heavy crude producing.And concerning marine heavy oil wells, because exploration and development expense height, characteristics such as platform space is narrow and small and application life is short objectively require to obtain within a short period of time higher oil recovery factor.At present the conventional waterflooding that adopts is cold adopts exploitation and is difficult to increase substantially thick oil recovery ratio, and the rate of oil production of expectation and ultimate recovery are well below the desired value of oil field development project, and economic benefit is relatively poor.Calculate according to offshore platform life-span and cold average 20% the ultimate recovery adopted, these oil fields are cold adopts to the exploitation time limit, also will have a large amount of remaining oils can not extraction, and how improve rate of oil production to improve ultimate recovery in limited platform lifetime, be a problem that presses for solution.

Therefore, need a kind of improved heavy oil wells production practice.

Summary of the invention

The purpose of this invention is to provide a kind of heavy oil wells multielement hot fluid thermal recovery technology.

Another object of the present invention provides a kind of marine heavy oil wells multielement hot fluid thermal recovery technology.

Another purpose of the present invention provides the purposes that multielement hot fluid is used to exploit land or marine heavy oil wells.

Heavy oil wells multielement hot fluid thermal recovery technology provided by the invention comprises multielement hot fluid and annular space nitrogen injection is together injected oil reservoir.

Marine heavy oil wells multielement hot fluid thermal recovery technology provided by the invention comprises the steps: that generating means is injected in fuel pressurization back to be mixed with air pressurized, after treating the igniter igniting in the generating means, fuel combustion is carried out interchange of heat with water after the processing of injecting and is produced multielement hot fluid; Then multielement hot fluid and the annular space nitrogen injection that produces together injected oil reservoir.

For straight well and inclined shaft, the amount of injecting multielement hot fluid is the 20-80t/m oil reservoir; For horizontal well, the amount of injecting multielement hot fluid is a 10-50t/m well section.

As used herein, term " heavy oil wells " refers generally to the land or marine heavy oil wells that the reservoir buried depth degree is 150-2000m, includes but not limited to following oil well: conventional completion heavy oil wells and thermal recovery completion heavy oil wells.

As used herein, term " multielement hot fluid " refers to that a kind of temperature range that contains steam, nitrogen, carbon dioxide and chemical agent can reach 120 ℃-350 ℃ hot fluid.Multielement hot fluid used herein can be to produce by the multielement hot fluid generation systems is on-the-spot, for example can burn at the generating means mesohigh by injecting fuel, the burning back produces high-temperature high-pressure fuel gas, feeding water again mixes with it and carries out interchange of heat, make water heat absorption vaporization, the steam and the combustion product gases mist that form HTHP are produced multielement hot fluid.

As used herein, term " fuel " comprises the fuel that this area is commonly used, includes but not limited to diesel oil, natural gas etc.

The present invention injects oil reservoir with multielement hot fluid, by the heating viscous crude, increases reservoir pressure and utilizes viscous crude and the gas gravity difference encourages heavy crude producing.A large amount of heat heating oil reservoirs that the multielement hot fluid that the present invention injects carries, nitrogen and carbon dioxide are when carrying heat, enlarging heated perimeter, can increase reservoir pressure, the gaseous mixture that captures in the top of oil horizon can effectively reduce the radiation loss to overlying rock.The nitrogen that oil pipe and casing annulus inject not only can reduce wellbore heat loss, can also increase reservoir pressure, plays the row of helping and production-increasing function.Nitrogen and carbon dioxide can improve the oil displacement efficiency of oil recovery process, and in addition, the gravity difference between viscous crude and nitrogen and the carbon dioxide also can be the displacement of reservoir oil power is provided, and especially heat-bodied oil is hidden and horizontal well.

When concrete exploitation,, determine rational multielement hot fluid temperature usually according to geology reservoir.For the heavy oil wells of viscosity of thickened oil under the reservoir condition less than 2000mPas, the temperature of injecting multielement hot fluid is generally getting final product more than 150 ℃; For the heavy oil wells of viscosity of thickened oil under the reservoir condition greater than 2000mPas, the temperature of injecting multielement hot fluid is generally more than 250 ℃.Actual temp requires and can wait to determine according to viscosity and temperature relation, oil well depth and the oil pipe effect of heat insulation of viscous crude.Can sand control screen be installed at the oil reservoir position during general straight well sand control, horizontal well then mainly adopts screen casing+gravel pack completion.When adopting the plain tubing gas injection or when reducing the insulated tubing heat waste, can be heat insulation at plain tubing or insulated tubing and casing annulus nitrogen injection.

In addition, the multielement hot fluid that injects oil reservoir is generally 1000～5000t, injection length is 10～30 days, the amount of injecting multielement hot fluid need wait to determine according to the core intersection of straight well (or inclined shaft) or the well segment length of horizontal well, for straight well and inclined shaft, the amount of injecting multielement hot fluid is 20～80t/m oil reservoir; For horizontal well, the amount of injecting multielement hot fluid is 10～50t/m well section.After finishing injection multielement hot fluid amount, close the interior generating means of generating means, stop water filling, annotate nitrogen, closing well 3～5 days, the open flow that drives a well recovers the oil, and after output is lower than certain value, is lowered to oil well pump oil recoveries such as electric submersible pump.

The process of injection, closing well and oil recovery is the cycle period of an injecting multielement hot fluid huff and puff oil recovery.After daily oil production is lower than certain value, restart the cyclic process of above-mentioned injection, closing well and oil recovery.A bite heavy oil wells can circulate, and the cycle daily average oil production can reach cold more than 2～3 times of daily oil production of oil pumping of adopting of conventional electric submersible pump more than the cycle in 10 of injecting multielement hot fluid exploitations, and recovery ratio can reach more than 20%.

When the present invention is used to exploit marine heavy oil wells, the present invention has adopted modular platform (offshore boring island or production platform) multielement hot fluid generation systems, form by little, the lightweight water treatment system of volume, air compressor and supercharger, generating means, oiling/water pump and connecting line etc., chemical such as anticorrosion if desired in addition can also be installed medicament cabin and injection pump.This generation systems mounts and dismounts on platform easily, is fit to the limited offshore platform condition in space, thereby has solved the difficult problem of marine heavy oil wells hot fluid source.This method is compared with adopting conventional steam generator circulation steam injection excitation heavy crude producing, has following advantage:

(1) energy-saving and emission-reduction, thermal efficiency height.Gas generator does not have flue gas emissions, and the thermal efficiency is up to 95%.Energy consumption is little, and the energy consumption of one ton of gas of every generation has only half of steam heating boiler.All injection is underground, environment pollution is little for the gas that produces.

(2) floor space is little, in light weight, and the skid mode is easy to vehicle-mounted and lifting, can directly gas injection on well head next door, and very flexible.

(3) from manually control combination, totally-enclosed combustion system, safety is higher.Generating means adopts totally-enclosed property combustion system, and flames of anger hidden danger is specially adapted to the offshore platform small size, the environment of imflammable gas enrichment.

(4) outlet multielement hot fluid temperature can reach more than 300 ℃, and under identical implantation quality, specific heat capacity is bigger, has improved the heated perimeter of oil reservoir.

(5) speed of injecting multielement hot fluid can reach more than 100～400t/d, and well head pressure can reach more than the 16MPa.

(6) CO of Chan Shenging₂And N₂Be partly dissolved in the crude oil, play the viscosity reduction effect, improve recovery ratio.

(7) because injecting gas can improve strata pressure, and produce the gravity difference effect between gas and the viscous crude, belonged to the enhanced recovery technology.

Oil production technology of the present invention is applicable to polytype land or marine heavy oil wells, uses conveniently, and has significantly improved heavy oil wells oil production and oil recovery.

The accompanying drawing summary

Fig. 1 is the schematic diagram of the generation systems of offshore platform multielement hot fluid according to an embodiment of the invention, wherein 1, fuel compartment, 2, water treatment system, 3, air compressor and supercharger, 4, filling pump, 5, water injecting pump, 6, generating means, 7, monitoring and control system, 8, multielement hot fluid, 9, medicament cabin and injection pump;

Fig. 2 is the schematic diagram of marine heavy oil wells multielement hot fluid injected system according to an embodiment of the invention, wherein 1, multielement hot fluid, and 2, nitrogen, 3, sleeve pipe, 4, plain tubing or insulated tubing, 5, packer, 6, screen casing or bushing pipe, 7, perforation borehole, 8, oil reservoir.

The specific embodiment

Below be that example has been explained General Principle of the present invention about the marine heavy oil wells in Bohai Sea Gulf, but should be noted that the present invention never is limited to marine heavy oil wells.

This heavy oil wells is a horizontal branch well, tiltedly dark 1195-1703m (oil reservoir middle part vertical depth 941m), and the on average vertical thick 7.9m of extended horizontal depth 517.25m, oil reservoir adopts the wire-wrapped screen completion, 50 ℃ of viscosity of thickened oil 1500mPas.This heavy oil wells adopts that daily average oil production was 35t/d when electric submersible pump is cold to be adopted.

At first with reference to figure 1, to generatingmeans 6, carry diesel oil fromfuel compartment 1 with the speed of 70-90kg/h by fillingpump 4, in generatingmeans 6, carry air pressurized (pressure is less than 25MPa) by air compressor and supercharger 3 with the speed of 1000-1200kg/h, after treating the igniter igniting in the generating means, diesel combustion, emit a large amount of heats and produce high-temperature gas mixture, carries in generatingmeans 6 with the speed of 6-8t/h bywater injecting pump 5 simultaneously that (water treatment system is according to the principle of reverse osmosis membrane separation via the water afterwater treatment system 2 processing, to coming the calcium in the water, magnesium, the sodium plasma panel separates, reduce electrical conductivity, thereby make water softening reach instructions for use).Emit a large amount of heats by diesel combustion, and carry out interchange of heat and produce multielementhot fluid 8 with water, wherein by monitoring andcontrol system 7 monitoring and control the injection rate of diesel oil, empty G﹠W and pressure (pressure of diesel oil, air, water is remained under the service pressure to get final product, the pressure of diesel oil, water is less than 35MPa in the present embodiment, and air pressure is less than 25MPa).Record that nitrogen is 25%-35% in the multielement hot fluid that is produced, carbon dioxide is 6%-10%, and water and steam are 50%-65%.

Then with reference to figure 2, with the temperature that produces is 120 ℃, and pressure is that the multielementhot fluid 1 of 9-11MPa is delivered to well head through surface line, is delivered to the shaft bottom by plain tubing or insulatedtubing 4, throughperforation borehole 7 multielementhot fluid 1 is injectedoil reservoir 8 at the place, shaft bottom, injection rate is 175m³/ d-190m³/ d, the injection total amount is 5170t.To the annular spacecontinuous nitrogen injection 2 ofoil pipe 4 withsleeve pipe 3, injection rate is 400-600Nm simultaneously³/ h.

After finishing injection, close generating means, stop water filling, annotate nitrogen, closing well 4 days, the open flow that drives a well recovers the oil, and blowing was lowered to electric submersible pump production after 6 days, after output is lower than 30 sides, restart the cyclic process of above-mentioned injection, closing well and oil recovery, can carry out 10 more than the cycle.

According to the above working method of the present invention this heavy oil wells oil reservoir is injected the multielement hot fluid huff and puff oil recovery, average day produce oil 61t/d.

The present invention can summarize with other the concrete form without prejudice to spirit of the present invention or principal character.Therefore, no matter from which point, above-mentioned embodiment of the present invention all can only be thought exemplary illustration of the present invention rather than restriction the present invention, claims have been pointed out scope of the present invention, therefore, in implication suitable and any change in the scope, all think to be included in the scope of claims with claims of the present invention.

Claims (4)

1. a heavy oil wells multielement hot fluid thermal recovery technology comprises described multielement hot fluid and annular space nitrogen injection is together injected oil reservoir.

2. a marine heavy oil wells multielement hot fluid thermal recovery technology comprises the steps:

Generating means is injected in fuel pressurization back mixes with air pressurized, treat the igniter igniting in the described generating means after, fuel combustion is carried out interchange of heat with water after the processing of injection and is produced multielement hot fluid; Then multielement hot fluid and the annular space nitrogen injection that produces together injected oil reservoir.

3. technology as claimed in claim 2 is characterized in that, in described step, for straight well and inclined shaft, the amount of injecting described multielement hot fluid is the 20-80t/m oil reservoir; For horizontal well, the amount of injecting described multielement hot fluid is a 10-50t/m well section.

4. multielement hot fluid is used to exploit the purposes of land or marine heavy oil wells.

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