CA2286245A1 - Method of oilfield development - Google Patents
Method of oilfield development Download PDFInfo
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- CA2286245A1 CA2286245A1 CA002286245A CA2286245A CA2286245A1 CA 2286245 A1 CA2286245 A1 CA 2286245A1 CA 002286245 A CA002286245 A CA 002286245A CA 2286245 A CA2286245 A CA 2286245A CA 2286245 A1 CA2286245 A1 CA 2286245A1
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Abstract
The invention is referred to the oil industry and namely to methods of oilfield development through waterflood and aims at lowering the costs and raising ecological benefits of methods of near well bore area cleanup from plugging particles through their dispersion and dissolving by the impact of ultrasound in the active liquid media until the deposits turn into a thinly dispersed hydrophobic suspension with the dimensions of solid particles within 0.5-20 µm with further injection of formed suspension into the reservoir to level out injectivity profile and decrease water inflow in producing wells.
Active liquid with surface tension on the vapor contact within 20-35 mPa-sec-1 (erg/cm2), density exceeding flood water density by no less that 100 kg/m3 and viscosity equal to water phase viscosity or exceeding it by no more than 20 times is use.
The optimum parameters of ultrasound impact are selected based on the results of prior laboratory testing of ultrasound dispersed sediment that was collected form the near well bore area. The testing is performed in various active liquids that provides a thinly dispersed hydrophobic suspension with the dimensions of particles within 0.5-20 µm.
Treating the near well bore area of wells with little sediment or wells that were previously cleaned from sediment through other methods to form thinly dispersed hydrophobic suspension in the near well bore area for its later use to block highly permeable reservoir intervals in place of active liquid media a dispersion of petroleum sludge-waste is injected into the well. The sludge is previously blended with the active liquid media, volume ratio being between 1:10 and 1:5 depending on the content of solid phase in the sludge.
Active liquid with surface tension on the vapor contact within 20-35 mPa-sec-1 (erg/cm2), density exceeding flood water density by no less that 100 kg/m3 and viscosity equal to water phase viscosity or exceeding it by no more than 20 times is use.
The optimum parameters of ultrasound impact are selected based on the results of prior laboratory testing of ultrasound dispersed sediment that was collected form the near well bore area. The testing is performed in various active liquids that provides a thinly dispersed hydrophobic suspension with the dimensions of particles within 0.5-20 µm.
Treating the near well bore area of wells with little sediment or wells that were previously cleaned from sediment through other methods to form thinly dispersed hydrophobic suspension in the near well bore area for its later use to block highly permeable reservoir intervals in place of active liquid media a dispersion of petroleum sludge-waste is injected into the well. The sludge is previously blended with the active liquid media, volume ratio being between 1:10 and 1:5 depending on the content of solid phase in the sludge.
Description
METHOD OF OILFIELD DEVOPMENT
The invention is referred to the oil industry and namely to the methods of field development through watertlood pressure control. These methods aim at raising oil recovery, however in permeability heterogeneous reservoirs typical for most pools early breakthrough of water often happen imo production wells. Due to large differences in transmissibility water filtration into low permeability intervals is negligible, i.e. they are excluded from production. Besides, water breakthrough to the well bore of the producing wells leads to the increase of pressure in highly flooded intervals which results in the decrease oil flow from other low filtration reservoir sections into highly permeable intervals and a decrease of produced oil and undeveloped intervals and sections.
Known are methods of avoiding selective water filtration into more permeable intervals and decreasing watercut in the product. They involve creating water blocking barriers in high permeability sections through injection of various dispersions of fibrous, granular and powder materials, emulsion, foams and various gel or sediment forming compounds ("Increasing efficiency of water injection wells. Summary." VNIIOENG, "Oil industry"
series, M., 1982, #22 (46) 34 c.; "Applications of Chemicals for Well Stimulation".
Reference book. M. 1991, page 46-72; "Modern Methods of Enhanced Recovery and New Technologies in the Russian Oilfield". The Russian Federation. Oil Industry. # 10, 1993, page 6-15).
These methods aim at increasing displacement rate, however, the methods are not sufFlciently efficient, technically complicated, they require specialized dispersion, solution and injection equipment for chemicals and their compositions, certain methods are expensive. All these are factors that limit extensive application of the methods in the oilfield. Besides, the application of known methods controlling sweep coverage and decreasing watercut focus on preparation work, i.e. cleaning the near well bore area and in particular its highly permeable intervals from plugging substances composed of solid mineral particles of various dimensions and chemical nature and viscous (paste-like) organic mass composed mostly of highly fusible paraffin and heavy asphaltene-resin components (PARC) of oil. This complicaxes and in certain cases makes impossible injection of certain water blocking agents into the reservoir without prior cleanup.
Most often various acid or heat treatments, surfactant and other chemical injection are applied to cleanup the near well bore area. This drastically complicates available methods leveling out injectivity profile and decreasing watercut and makes them more expensive.
There exists a known method of well operation (Patent RU 2094594 C 1, 6, E 21 B 43!00, 27.10.97, #30) where to create conditions for continuous oil extraction a vibrating acoustic emitter is lowered into the producing well through the lubricator on the wireline.
The emitter is tuned in the cavitation regime (15-100 kHz) and is lowered to the mark of oil bubble pressure. Later to promote gas separation (artificial gaslift) the source of acoustic vibraxions is repetitively moved above and below the mark.
The disadvantage of the method is a short lasting and insufficient effect of ultrasound impact on the oil and gas separation. Operating flooded oil well through this method it is possible for a stable highly dispersed water-in-oil emulsion to form.
According to another available method of treating the near well bore area (KG
C1, 6 E 21 B 43/25, 27.02.98) an impulse pressure generator is lowered into the perforation interval and located at the bottom part with the most oil and gas saturation and flow intensity. The impulse of 250-400 kJ is created and vibrations last until their complete damping after which impulses of 6-8 kJ and 10-15 Hz in frequency are generated. When the impulse treatment is completed and prior to removing the generator from the well a deep drawdown is created in the perforation interval for more complete cleanup of the near well bore area form the mechanical impurities and well stimulation.
The disadvantage of the method is bringing the cleanup products to the surface and a possibility of water flow increase in the producing wells as a result of additional micro fractiues forming in the near well bore area as a result of impact pulses of 250-400 kJ
There exists a known method of treating the near well bore area of oil wells and a tool for its~application (RU # 2055979 C1, 6E 21 B 43/00, 10.03.96 #7) chosen as a prototype of the proposed method. The prototype involves well shut-down, injection of brine, locating an acoustic emitter at the flooded level of the interval and 22-42 kHz frequency impact on the near well bore area at cyclic relocation of the emitter for 05-1.0 hour with the ultrasound field of 0.05-2. S kW. Later the acoustic emitter is brought to the surfae and the well is started Using brine (salt water) with low physical and chemical properties (dissolving and peptizing properties) towards oil PARC as a fluid media for ultrasound cleanup of plugging substances containing a sufl'lcient PARC volume is the major disadvantage of this method. Another disadvantage as it will be described further, is the frequency range for ultrasound cleanup (dispersion) of solid substances.
The objective of the invention is to develop the method fiuther, decrease costs and increase environmental benefits. The method uses solid hydrophobic particles 0.5 - 20 la,m in dimensions that form at ultrasound dispersion of sediment (accumulating in the near well bore area in the process of drilling, servicing and production) in an active in relation to sediment liquid with liquid-vapor surface tension within 20-35 mPa cm (erg/cm2), density exceeding injection water density by no less than 100 kg/m3 and viscosity equal to water phase viscosity or no more than 20 times over it and PARC of oil contained in the sediment as hydrophobic agents that form molecular or oolloid-dispersion systems in the active liquid under the impact of ultrasound. The method is used to create a hydrophobic barrier permeable for oil and low permeable for water in high permeability intervals and fractures of the near well bore area.
Liquid media with aforementioned parameters that are based on the general understanding of the mechanism of solid bodies dispersion in the ultrasound field has a significant impact on the efficiency of the dispersion prows. The media is:
Blends (solutions) of low viscous oil (petroleum products) and heavy non-polar fluids, i.e. tetrachlormethane (Standard 20288-74), APK agent (TU 122-199-05-34-68-94) etc. and Solutions of various surfactants in salt water with density and concentration complying with the aforementioned requireme~s and concentration that drops the surface tension of the solution at the contact with air (vapor) to required numbers.
Ultrasound dispersion (destruction) of a solid body in liquid media ('~7ltrasound Technology", m., "Mettalurgia", 1974, page 285-293, "Ultrasound Eguipment", issue 2, 1963, page 52-57) is defined mostly by the cavitation process and acoustic micro flows.
Cavitation bubbles that form under the impact of ultrasound are concentrated mostly on the solid particles and micro fractures and bumps on their surface. Later under the influence of intensive micro flows formed by the impulses of the bubbles, pores groves and micro fractures on the surface of the particles fill with liquid. Gas (fluid vapor) compresses to several thousand Atmospheres inside the cavity that decreases in dimensions approximately to 1 pnn. Rapid secondary expansion of the bubble provides micro impact action of cavitation that leads to breakup (dispersion) of solid particles.
Based on these notions, the lower the viscosity and surface tension of liquid and the higher its density, the more effective are the aforementioned cavitation processes.
Properties of a solid body (brittleness, hardness, continuity) also have a considerable influence on frequency, intensity and time of ultrasound dispersion of particles in various liquid and the quality of resulting dispersion. For example, the best dispersion (particle dimensions no less than 0.1 lun) for kaoline in water is achieved at 960 kHz, for monmorilonite it is 320 kHz, for gypsum 16 kHz, for organic solid material 22 and 42 kHz.
Therefore, for the proposed method the optimum fi~equency of the ultrasound generator is set in each case based on the data of micro analysis of dispersions formed at various frequencies of dispersion of sediment collected from the near well bore area in the liquid media.
Focusing on the impact that viscosity and surface tension on the vapor contact have upon the process of cavitation the lower these parameters are the more effective the dispersion process, for proposed liquids these parameters are minimum. Density of active fluid media injected into the well under the reservoir water layer should be no less that 100 kglm3 more than the reservoir water density for the two types of water not to mix.
Therefore, the major distinctions of the proposed method are:
1. Lowering the tubing to the bottom hole 2. Injection of liquid media through tubing 3. Lifting the tubing to the surface 4. Lowering the ultrasound emitter to the bottom hole 5. Setting optimum parameters of ultrasound impact based on prior laboratory tests at various frequencies intensity and time of ultrasound dispersion of the sediment collected from the near well bore area in various media providing dispersion with solid particles dimensions within 0.5-20 N.m.
The invention is referred to the oil industry and namely to the methods of field development through watertlood pressure control. These methods aim at raising oil recovery, however in permeability heterogeneous reservoirs typical for most pools early breakthrough of water often happen imo production wells. Due to large differences in transmissibility water filtration into low permeability intervals is negligible, i.e. they are excluded from production. Besides, water breakthrough to the well bore of the producing wells leads to the increase of pressure in highly flooded intervals which results in the decrease oil flow from other low filtration reservoir sections into highly permeable intervals and a decrease of produced oil and undeveloped intervals and sections.
Known are methods of avoiding selective water filtration into more permeable intervals and decreasing watercut in the product. They involve creating water blocking barriers in high permeability sections through injection of various dispersions of fibrous, granular and powder materials, emulsion, foams and various gel or sediment forming compounds ("Increasing efficiency of water injection wells. Summary." VNIIOENG, "Oil industry"
series, M., 1982, #22 (46) 34 c.; "Applications of Chemicals for Well Stimulation".
Reference book. M. 1991, page 46-72; "Modern Methods of Enhanced Recovery and New Technologies in the Russian Oilfield". The Russian Federation. Oil Industry. # 10, 1993, page 6-15).
These methods aim at increasing displacement rate, however, the methods are not sufFlciently efficient, technically complicated, they require specialized dispersion, solution and injection equipment for chemicals and their compositions, certain methods are expensive. All these are factors that limit extensive application of the methods in the oilfield. Besides, the application of known methods controlling sweep coverage and decreasing watercut focus on preparation work, i.e. cleaning the near well bore area and in particular its highly permeable intervals from plugging substances composed of solid mineral particles of various dimensions and chemical nature and viscous (paste-like) organic mass composed mostly of highly fusible paraffin and heavy asphaltene-resin components (PARC) of oil. This complicaxes and in certain cases makes impossible injection of certain water blocking agents into the reservoir without prior cleanup.
Most often various acid or heat treatments, surfactant and other chemical injection are applied to cleanup the near well bore area. This drastically complicates available methods leveling out injectivity profile and decreasing watercut and makes them more expensive.
There exists a known method of well operation (Patent RU 2094594 C 1, 6, E 21 B 43!00, 27.10.97, #30) where to create conditions for continuous oil extraction a vibrating acoustic emitter is lowered into the producing well through the lubricator on the wireline.
The emitter is tuned in the cavitation regime (15-100 kHz) and is lowered to the mark of oil bubble pressure. Later to promote gas separation (artificial gaslift) the source of acoustic vibraxions is repetitively moved above and below the mark.
The disadvantage of the method is a short lasting and insufficient effect of ultrasound impact on the oil and gas separation. Operating flooded oil well through this method it is possible for a stable highly dispersed water-in-oil emulsion to form.
According to another available method of treating the near well bore area (KG
C1, 6 E 21 B 43/25, 27.02.98) an impulse pressure generator is lowered into the perforation interval and located at the bottom part with the most oil and gas saturation and flow intensity. The impulse of 250-400 kJ is created and vibrations last until their complete damping after which impulses of 6-8 kJ and 10-15 Hz in frequency are generated. When the impulse treatment is completed and prior to removing the generator from the well a deep drawdown is created in the perforation interval for more complete cleanup of the near well bore area form the mechanical impurities and well stimulation.
The disadvantage of the method is bringing the cleanup products to the surface and a possibility of water flow increase in the producing wells as a result of additional micro fractiues forming in the near well bore area as a result of impact pulses of 250-400 kJ
There exists a known method of treating the near well bore area of oil wells and a tool for its~application (RU # 2055979 C1, 6E 21 B 43/00, 10.03.96 #7) chosen as a prototype of the proposed method. The prototype involves well shut-down, injection of brine, locating an acoustic emitter at the flooded level of the interval and 22-42 kHz frequency impact on the near well bore area at cyclic relocation of the emitter for 05-1.0 hour with the ultrasound field of 0.05-2. S kW. Later the acoustic emitter is brought to the surfae and the well is started Using brine (salt water) with low physical and chemical properties (dissolving and peptizing properties) towards oil PARC as a fluid media for ultrasound cleanup of plugging substances containing a sufl'lcient PARC volume is the major disadvantage of this method. Another disadvantage as it will be described further, is the frequency range for ultrasound cleanup (dispersion) of solid substances.
The objective of the invention is to develop the method fiuther, decrease costs and increase environmental benefits. The method uses solid hydrophobic particles 0.5 - 20 la,m in dimensions that form at ultrasound dispersion of sediment (accumulating in the near well bore area in the process of drilling, servicing and production) in an active in relation to sediment liquid with liquid-vapor surface tension within 20-35 mPa cm (erg/cm2), density exceeding injection water density by no less than 100 kg/m3 and viscosity equal to water phase viscosity or no more than 20 times over it and PARC of oil contained in the sediment as hydrophobic agents that form molecular or oolloid-dispersion systems in the active liquid under the impact of ultrasound. The method is used to create a hydrophobic barrier permeable for oil and low permeable for water in high permeability intervals and fractures of the near well bore area.
Liquid media with aforementioned parameters that are based on the general understanding of the mechanism of solid bodies dispersion in the ultrasound field has a significant impact on the efficiency of the dispersion prows. The media is:
Blends (solutions) of low viscous oil (petroleum products) and heavy non-polar fluids, i.e. tetrachlormethane (Standard 20288-74), APK agent (TU 122-199-05-34-68-94) etc. and Solutions of various surfactants in salt water with density and concentration complying with the aforementioned requireme~s and concentration that drops the surface tension of the solution at the contact with air (vapor) to required numbers.
Ultrasound dispersion (destruction) of a solid body in liquid media ('~7ltrasound Technology", m., "Mettalurgia", 1974, page 285-293, "Ultrasound Eguipment", issue 2, 1963, page 52-57) is defined mostly by the cavitation process and acoustic micro flows.
Cavitation bubbles that form under the impact of ultrasound are concentrated mostly on the solid particles and micro fractures and bumps on their surface. Later under the influence of intensive micro flows formed by the impulses of the bubbles, pores groves and micro fractures on the surface of the particles fill with liquid. Gas (fluid vapor) compresses to several thousand Atmospheres inside the cavity that decreases in dimensions approximately to 1 pnn. Rapid secondary expansion of the bubble provides micro impact action of cavitation that leads to breakup (dispersion) of solid particles.
Based on these notions, the lower the viscosity and surface tension of liquid and the higher its density, the more effective are the aforementioned cavitation processes.
Properties of a solid body (brittleness, hardness, continuity) also have a considerable influence on frequency, intensity and time of ultrasound dispersion of particles in various liquid and the quality of resulting dispersion. For example, the best dispersion (particle dimensions no less than 0.1 lun) for kaoline in water is achieved at 960 kHz, for monmorilonite it is 320 kHz, for gypsum 16 kHz, for organic solid material 22 and 42 kHz.
Therefore, for the proposed method the optimum fi~equency of the ultrasound generator is set in each case based on the data of micro analysis of dispersions formed at various frequencies of dispersion of sediment collected from the near well bore area in the liquid media.
Focusing on the impact that viscosity and surface tension on the vapor contact have upon the process of cavitation the lower these parameters are the more effective the dispersion process, for proposed liquids these parameters are minimum. Density of active fluid media injected into the well under the reservoir water layer should be no less that 100 kglm3 more than the reservoir water density for the two types of water not to mix.
Therefore, the major distinctions of the proposed method are:
1. Lowering the tubing to the bottom hole 2. Injection of liquid media through tubing 3. Lifting the tubing to the surface 4. Lowering the ultrasound emitter to the bottom hole 5. Setting optimum parameters of ultrasound impact based on prior laboratory tests at various frequencies intensity and time of ultrasound dispersion of the sediment collected from the near well bore area in various media providing dispersion with solid particles dimensions within 0.5-20 N.m.
6. Application of active liquids for effective dispersion of solids in the ultrasound field in the near well bore area. Liquids have surface tension of 20-35 mPa.sec-1 (erg/cm2) at liquid-vapor contact, density that is no less than 100 kg/m3 over the density of flood water and viscosity equal to water phase viscosity or exceeding it no more than 20 times. It is proposed to use blends (solutions) of low viscous oil and liquid petroleum products and viscous non-polar fluids, i.e. tetrachlormethane, APK
agent (TU 2122-199-OS-76-34-68-94) etc. or solutions of various surfactants in salt water with density complying with the aforementioned requirements and concentration of surfactant in solution that drops the surface tension of the solution at the contact with xir (vapor) to required maximum numbers.
agent (TU 2122-199-OS-76-34-68-94) etc. or solutions of various surfactants in salt water with density complying with the aforementioned requirements and concentration of surfactant in solution that drops the surface tension of the solution at the contact with xir (vapor) to required maximum numbers.
7. Application of solid hydrophobic particles of 0.5-20 p,m formed at the bottom hole by ultrasound dispersion in active liquid media. The particles are mineral solids of various dimensions and chemical nature composing treated sediment. This will create a hydrophobic barrier permeable for oil and low permeable for water in the near well bore area.
8. As hydrophobic agents for the solids and reservoir rock surface the application of PARC of oil that compose the sediment which forms molecular or colloid dispersions in the liquid media under the impact of ultrasound.
9. Upon the completion of the process of ultrasound treatme~ the application of thinly dispersed hydrophobic dispersion of solids and oil PARC in their complete volume to regulate injectivity profile and create water blocking barrier in producing wells.
10. Should the near well bore area treated by the active liquid media and the ultrasound contain no sediment and plugging deposits (or contain little sedimem) to prepare a thinly dispersed suspension of solid particles and oil PARC in the near well bore area in the ultrasound field instead of active liquid media (distinct feature 6) a dispersion of oil sludge waste is injected such as bottom sedimem formed in holding tanks while storing merchantable oil. The sludge is mixed prior to that with active liquid media at the pump (or another blender) at volume ratio between 1:10 and 1:5 depending on the solids convent in the oil sludge.
Features 1,2,3 and 4 are common with the prototype and known methods, features 5,6,7;8,9 and 10 are not traced in known in the industry technical approaches.
Consequently, the proposed method complies with "sufficient distinctions"
category.
The method is applied as follows:
The type of active liquid media (ALM) that should be used for ultrasound treatment of the near well bore area is determined for the well selected for the enhanced recovery program based on the geological parameters of the reservoir and current development parameters as well as results of prior laboratory testing. Major ultrasound generator parameters are determined as well.
Depending on the type of ALM the procedure of its preparation contains:
For hydrocarbon based ALM: blending of low viscosity oil or any petroleum product (benzene, kerosene etc) with heavy low viscosity non-polar liquid i. e.
tetrachlormethane (GOST 20288-74) or APK agent (YU 2122-199-OS-76-34-68-94) at such volume ratio that the specific weight (density) of the blend (solution) exceeds the density of flood water by no less than 100 kg/m3. The density of water used in flooding varies between 1,000-1,120 kg/m3. Correspondingly, the density of hydrocarbon ALM can vary between 1,100 and 1,220 kg/m3. Based on the chemical nature of blended non-polar fluids with low numbers of surface tension at the Liquid-vapor contact hydrocarbon AFM wih have surface tension not over 20-35 mPa.seo-l (erg/cm2) and viscosity within 1-20 cPs at 20°C.
For water based ALM (produced water is used, i.e. salt water): to dissolve a required volume (between 5 and 10% of mass) of water soluble surfactarn (preferably non-ionic) such as AF-12 (TU 38.507-63-171-91), CHO-3B (1'U 39-579-46-88) and others which would provide a decrease of surface tension of water at the vapor conta,cx from 72-73 mPa seo-l (erg/cm2) and if required additionally dissolve a certain volume of chloride salts, i.e. calcium chloride, sodium chloride etc. in produced water so that the density of water based ALM would exceed the density of flood water by no less than 100 kg/m3 Table 1 Ultrasound dispersion of various sediment forming materials and oil sludge waste in various liquid media.
a anal zed sedimentand slu onents erties oil a and their pro comp # Code ~tnd Com onenta, Pro riles % of mass ' source of solids PARC Emul~ed Specific PreoentaNon Sam le ( water mwss kg/m3 1 Material #1 35.2 41.7 23.1 1,330 Viscous (sediment from sticky ' in black mass ector 2 Material #2 25.4 52.9 21.7 1,110 Same, dark (sediment from brown roducer 3 Material #3 47.4 12.3 40.3 1,420 Concentrat (concentrated ed brown waste of drilling pie mud 4 Material #4 10.2 44.3 25.5 1,210 Viscous (bottom sticky sediment from black mass a holding tank, merchantable oii stor a b ro 'es of ion li uid in was which ultrasound undertaken dis # Code and Li uid fro-perties major Density, Surface Viscosity lig/m3 tension re water components mPa/sec- (conventional unit) a cm2 1 Liquid #1 1,050 73.0 1 (water brine)-roto a 2 Liquid #2 1,160 25.0 1-5*) (hydrocarbon proposed method 3 Liquid #3 1,160 30.0 1 (salt water AFM
+
f sur actant c) description of systems formed after dispersion of analyzed sediment forming materials by ltrasound u in various fluid. Content of dispersed sediment in the system:
15% of mass-const.
# Contents Pro erties stem of of formed dispersed Presenta- Dimensions Particles~m V'iscoaity (cm-4) to g~nl lion (minimum) (maiimum)(average) water 1 Material Flaky 1,000 5,000 2,000 -**) #1+Liquid separating #1 rot s stem 2 Material Homogene 1 20 S.0 15-50*) #1+Liquid ous low #2 (proposed) viscosity hydropho-bic sus nsion 3 Material Flaky 1,000 5,000 2,000 -**) #2+Liquid separating #1 roto s stem 4 Material Homogene 1 20 5.0 15-50*) #2+Liquid ous low #2 (proposed) viscosity hydropho-bic sus ension Material Homogene 10 50 20 15 ' #3+Liquid ous low #1 (prototype) viscosity sus nsion 6 Material Homogene 1 20 5.0 15-50*) #3+Liquid#1 ous low (proposed) viscosity hydropho-bic sus nsion 7 Material Flaky 1,000 5,000 2,~0 -**) #4+Liquid separating # 1 roto a s stem 8 Material Homogene 1 20 5.0 15-50*) #4+Liquidd#2ous low (proposed) viscosity sus nsion 9 Material Homogene 0.5 5 10 15 #1+Liquid#3 ous low (proposed) viscosity sus sion Material Low 0.5 5 10 15 #2+Liquid viscosity #3 (proposed) homogene ous su nsion 11 Material Low 0.5 S 10 10 #3+Liquid viscosity #3 (proposed) homogene ous sus nsion Reference:
*) Viscosity of hydrocarbon ALM
mainly depends on viscosity of the hydrocarbon liquid selected to be blended with the non-polar heavy solvent such as tetrachlormethane or APK, viscosity of which is similar to water viscosity at **) Due to high adhesion property (stickiness) and low kinetic stability (tendency to separate) the rheological properties of the system were not established.
Di ersion conditions are constant for ev test.
Table 2 Nature of change in phase permeability (filtration velocity) of oii and water through heterogeneous highly permeable reservoir model (K=1 and over lunm2) depending on the type of dispersion system selected for reservoir treatmem.
# Dispersion Filtration Change velocity, (decrease, mm/min system mufti le Oil Vo Watcr Vo after Vw after Vw Vo Vo Vw Vw Vo prior Vw prior rior after rior after 1 System #1 15 0 53 0 0 ~ ~ 0 roto a 2 System #2 16 12 55 2 1.3 27.5 ro sed 3 System #3 15 0 50 0 0 0 roto 4 System #4 16 13 50 5 1.2 10.0 ro sed S System #5 15 0 54 0 0 0 rot a 6 System #6 16 14 53 7 1.1 7.5 ro sed 7 System #7 15 0 58 0 0 0 roto a 8 System #8 16 13 55 4 1.2 13.7 ro sed 9 System #9 16 15 56 25 I.06 2.2 roto a System #10 15 14 57 29 1.07 2.0 ro sed 11 System #1 16 14 55 27 1.1 2.0 i ro sed Preparation method and description of analyzed dispersions are contained in Table 1.
Filtration conditions for all tests were constant, volume of injected suspension was 1 pore volume of the reservoir.
METHOD OF OILFIELD DEVOPMENT
Invention formula 1. Method of oilfield development includes creating a hydrophobic barner with selective phase permeability (low for water and high for oil) in high permeability intervals and fractures of the near well bore area includes lowering the tubing to the bottom hole, injection of liquid media through tubing into the near well bore area, lifting the tubing to the surface, lowering the ultrasound emitter with frequency range 10-15 kHz, 22-44 kHz and 320-964 kHz into the liquid media and locating it at treated reservoir interval. The method is distinct due to the fact that to modify it, cut costs and increase environmemal benefits cleanup of the near well bore area from sediment and other plugging particles is done through their dispersion and dissolving under the impact of ultrasound in active liquid media until the products of cleanup turn into thinly dispersed hydrophobic suspension with the dimensions of solid particles of 0.5-wln.
2. The method, as per paragraph 1 is distinct due to the fact that as active liquid media a fluid is use with low surface tension on liquid-vapor contact (20-35 mPa-sec-I) (erg/cm2), density exceeding the density of flood water by no less than 100 kg/m3 and viscosity equal to water phase viscosity or exceeding it by no more than 20 times.
3. The method as per paragraphs 1 and 2 is distinct due to the fact that as active liquid media blends (solutions) of low viscosity oil (or petroleum products) and heavy non-polar fluid such as tertachlormethane, APK agent (TU 2122-199-OS-76-34-68-94);
or 5-10% solutions of various surfactants (primarily non-ionic surfactants) in salt water with density exceeding density of flood water by no less than 100 kg/m3 are used.
4. The method, as per paragraphs 1, 2 and 3 is distinct due to the fact that setting optimum parameters of ultrasound impact on the near well bore area is performed on the basis of prior laboratory testing of ultrasound dispersion conditions for the sediment collected in the near well bore area. The testing is performed in various active liquid media and provides thinly dispersed hydrophobic suspension with the dimensions of solid phase of 0.5-20 Eun.
5. The method, as per paragraphs 1, 2, 3 and 4 is distinct due to the fact that as hydrophobic agents for the surface of thinly dispersed solid particles and rock surface of the reservoir asphaltene-resin and paraffin components (PARC) of oil are used that compose the sediment and form molecular and colloid dissolved hydrophobic dispersion systems in the active liquid media under the impact of ultrasound.
6. The method, as per paragraphs 1, 2, 3, 4 and 5 is distinct due to the fact that after the process of ultrasound treatment of the near well bore area is completed formed thinly dispersed hydrophobic suspension in its complete volume is used to level out the injectivity profile or create a water blocking hydrophobic barrier to limit water inflow in producing wells.
7. The method, as per paragraphs 1, 2, 3, 4, 5 and 6 is distinct due to the fact that treating the near well bore area of wells with little sediment or wells that were previously cleaned from sediment through other methods to form thinly dispersed hydrophobic suspension in the near well bore area before running the ultrasound wave generator into the well in place of active liquid media a dispersion of petrol~m sludge-waste is injected into the well (i.e. bottom sediment formed in storage tanks) that were blended with the active liquid media at the pump (or other blender) prior to that, volume ratio being between 1:10 and 1: 5 depending on the content of solid phase in the sludge.
Abstract The invention is referred to the oil industry and namely t s of oilfield development through waterflood and aims at g the costs and raising ecological benefits of methods of near well cleanup from plugging particles through their dispersion and dissol ' a impact of ultrasound in the active liquid media umil the deposits a thinly dispersed hydrophobic suspension with the dimensions of solid es within 0.5-20 pm with further injection of formed suspension into the reservoir
Features 1,2,3 and 4 are common with the prototype and known methods, features 5,6,7;8,9 and 10 are not traced in known in the industry technical approaches.
Consequently, the proposed method complies with "sufficient distinctions"
category.
The method is applied as follows:
The type of active liquid media (ALM) that should be used for ultrasound treatment of the near well bore area is determined for the well selected for the enhanced recovery program based on the geological parameters of the reservoir and current development parameters as well as results of prior laboratory testing. Major ultrasound generator parameters are determined as well.
Depending on the type of ALM the procedure of its preparation contains:
For hydrocarbon based ALM: blending of low viscosity oil or any petroleum product (benzene, kerosene etc) with heavy low viscosity non-polar liquid i. e.
tetrachlormethane (GOST 20288-74) or APK agent (YU 2122-199-OS-76-34-68-94) at such volume ratio that the specific weight (density) of the blend (solution) exceeds the density of flood water by no less than 100 kg/m3. The density of water used in flooding varies between 1,000-1,120 kg/m3. Correspondingly, the density of hydrocarbon ALM can vary between 1,100 and 1,220 kg/m3. Based on the chemical nature of blended non-polar fluids with low numbers of surface tension at the Liquid-vapor contact hydrocarbon AFM wih have surface tension not over 20-35 mPa.seo-l (erg/cm2) and viscosity within 1-20 cPs at 20°C.
For water based ALM (produced water is used, i.e. salt water): to dissolve a required volume (between 5 and 10% of mass) of water soluble surfactarn (preferably non-ionic) such as AF-12 (TU 38.507-63-171-91), CHO-3B (1'U 39-579-46-88) and others which would provide a decrease of surface tension of water at the vapor conta,cx from 72-73 mPa seo-l (erg/cm2) and if required additionally dissolve a certain volume of chloride salts, i.e. calcium chloride, sodium chloride etc. in produced water so that the density of water based ALM would exceed the density of flood water by no less than 100 kg/m3 Table 1 Ultrasound dispersion of various sediment forming materials and oil sludge waste in various liquid media.
a anal zed sedimentand slu onents erties oil a and their pro comp # Code ~tnd Com onenta, Pro riles % of mass ' source of solids PARC Emul~ed Specific PreoentaNon Sam le ( water mwss kg/m3 1 Material #1 35.2 41.7 23.1 1,330 Viscous (sediment from sticky ' in black mass ector 2 Material #2 25.4 52.9 21.7 1,110 Same, dark (sediment from brown roducer 3 Material #3 47.4 12.3 40.3 1,420 Concentrat (concentrated ed brown waste of drilling pie mud 4 Material #4 10.2 44.3 25.5 1,210 Viscous (bottom sticky sediment from black mass a holding tank, merchantable oii stor a b ro 'es of ion li uid in was which ultrasound undertaken dis # Code and Li uid fro-perties major Density, Surface Viscosity lig/m3 tension re water components mPa/sec- (conventional unit) a cm2 1 Liquid #1 1,050 73.0 1 (water brine)-roto a 2 Liquid #2 1,160 25.0 1-5*) (hydrocarbon proposed method 3 Liquid #3 1,160 30.0 1 (salt water AFM
+
f sur actant c) description of systems formed after dispersion of analyzed sediment forming materials by ltrasound u in various fluid. Content of dispersed sediment in the system:
15% of mass-const.
# Contents Pro erties stem of of formed dispersed Presenta- Dimensions Particles~m V'iscoaity (cm-4) to g~nl lion (minimum) (maiimum)(average) water 1 Material Flaky 1,000 5,000 2,000 -**) #1+Liquid separating #1 rot s stem 2 Material Homogene 1 20 S.0 15-50*) #1+Liquid ous low #2 (proposed) viscosity hydropho-bic sus nsion 3 Material Flaky 1,000 5,000 2,000 -**) #2+Liquid separating #1 roto s stem 4 Material Homogene 1 20 5.0 15-50*) #2+Liquid ous low #2 (proposed) viscosity hydropho-bic sus ension Material Homogene 10 50 20 15 ' #3+Liquid ous low #1 (prototype) viscosity sus nsion 6 Material Homogene 1 20 5.0 15-50*) #3+Liquid#1 ous low (proposed) viscosity hydropho-bic sus nsion 7 Material Flaky 1,000 5,000 2,~0 -**) #4+Liquid separating # 1 roto a s stem 8 Material Homogene 1 20 5.0 15-50*) #4+Liquidd#2ous low (proposed) viscosity sus nsion 9 Material Homogene 0.5 5 10 15 #1+Liquid#3 ous low (proposed) viscosity sus sion Material Low 0.5 5 10 15 #2+Liquid viscosity #3 (proposed) homogene ous su nsion 11 Material Low 0.5 S 10 10 #3+Liquid viscosity #3 (proposed) homogene ous sus nsion Reference:
*) Viscosity of hydrocarbon ALM
mainly depends on viscosity of the hydrocarbon liquid selected to be blended with the non-polar heavy solvent such as tetrachlormethane or APK, viscosity of which is similar to water viscosity at **) Due to high adhesion property (stickiness) and low kinetic stability (tendency to separate) the rheological properties of the system were not established.
Di ersion conditions are constant for ev test.
Table 2 Nature of change in phase permeability (filtration velocity) of oii and water through heterogeneous highly permeable reservoir model (K=1 and over lunm2) depending on the type of dispersion system selected for reservoir treatmem.
# Dispersion Filtration Change velocity, (decrease, mm/min system mufti le Oil Vo Watcr Vo after Vw after Vw Vo Vo Vw Vw Vo prior Vw prior rior after rior after 1 System #1 15 0 53 0 0 ~ ~ 0 roto a 2 System #2 16 12 55 2 1.3 27.5 ro sed 3 System #3 15 0 50 0 0 0 roto 4 System #4 16 13 50 5 1.2 10.0 ro sed S System #5 15 0 54 0 0 0 rot a 6 System #6 16 14 53 7 1.1 7.5 ro sed 7 System #7 15 0 58 0 0 0 roto a 8 System #8 16 13 55 4 1.2 13.7 ro sed 9 System #9 16 15 56 25 I.06 2.2 roto a System #10 15 14 57 29 1.07 2.0 ro sed 11 System #1 16 14 55 27 1.1 2.0 i ro sed Preparation method and description of analyzed dispersions are contained in Table 1.
Filtration conditions for all tests were constant, volume of injected suspension was 1 pore volume of the reservoir.
METHOD OF OILFIELD DEVOPMENT
Invention formula 1. Method of oilfield development includes creating a hydrophobic barner with selective phase permeability (low for water and high for oil) in high permeability intervals and fractures of the near well bore area includes lowering the tubing to the bottom hole, injection of liquid media through tubing into the near well bore area, lifting the tubing to the surface, lowering the ultrasound emitter with frequency range 10-15 kHz, 22-44 kHz and 320-964 kHz into the liquid media and locating it at treated reservoir interval. The method is distinct due to the fact that to modify it, cut costs and increase environmemal benefits cleanup of the near well bore area from sediment and other plugging particles is done through their dispersion and dissolving under the impact of ultrasound in active liquid media until the products of cleanup turn into thinly dispersed hydrophobic suspension with the dimensions of solid particles of 0.5-wln.
2. The method, as per paragraph 1 is distinct due to the fact that as active liquid media a fluid is use with low surface tension on liquid-vapor contact (20-35 mPa-sec-I) (erg/cm2), density exceeding the density of flood water by no less than 100 kg/m3 and viscosity equal to water phase viscosity or exceeding it by no more than 20 times.
3. The method as per paragraphs 1 and 2 is distinct due to the fact that as active liquid media blends (solutions) of low viscosity oil (or petroleum products) and heavy non-polar fluid such as tertachlormethane, APK agent (TU 2122-199-OS-76-34-68-94);
or 5-10% solutions of various surfactants (primarily non-ionic surfactants) in salt water with density exceeding density of flood water by no less than 100 kg/m3 are used.
4. The method, as per paragraphs 1, 2 and 3 is distinct due to the fact that setting optimum parameters of ultrasound impact on the near well bore area is performed on the basis of prior laboratory testing of ultrasound dispersion conditions for the sediment collected in the near well bore area. The testing is performed in various active liquid media and provides thinly dispersed hydrophobic suspension with the dimensions of solid phase of 0.5-20 Eun.
5. The method, as per paragraphs 1, 2, 3 and 4 is distinct due to the fact that as hydrophobic agents for the surface of thinly dispersed solid particles and rock surface of the reservoir asphaltene-resin and paraffin components (PARC) of oil are used that compose the sediment and form molecular and colloid dissolved hydrophobic dispersion systems in the active liquid media under the impact of ultrasound.
6. The method, as per paragraphs 1, 2, 3, 4 and 5 is distinct due to the fact that after the process of ultrasound treatment of the near well bore area is completed formed thinly dispersed hydrophobic suspension in its complete volume is used to level out the injectivity profile or create a water blocking hydrophobic barrier to limit water inflow in producing wells.
7. The method, as per paragraphs 1, 2, 3, 4, 5 and 6 is distinct due to the fact that treating the near well bore area of wells with little sediment or wells that were previously cleaned from sediment through other methods to form thinly dispersed hydrophobic suspension in the near well bore area before running the ultrasound wave generator into the well in place of active liquid media a dispersion of petrol~m sludge-waste is injected into the well (i.e. bottom sediment formed in storage tanks) that were blended with the active liquid media at the pump (or other blender) prior to that, volume ratio being between 1:10 and 1: 5 depending on the content of solid phase in the sludge.
Abstract The invention is referred to the oil industry and namely t s of oilfield development through waterflood and aims at g the costs and raising ecological benefits of methods of near well cleanup from plugging particles through their dispersion and dissol ' a impact of ultrasound in the active liquid media umil the deposits a thinly dispersed hydrophobic suspension with the dimensions of solid es within 0.5-20 pm with further injection of formed suspension into the reservoir
Claims (7)
HERE IS WHAT WE CLAIM:
1. Procedure to develop oil fields due to creation (in highly permeable sectors and is fractures of bottom hole zone) a hydrophobic barrier with selective phase permeability (small for water and high for oil), that includes the run-in of tubing up to the bottom hole;
injection of a process fluid through this tubing into the bottom hole area of the pay, the run out of the tubing to the surface, the rim in (in the volume of process fluid in the interval under treatment) of the ultrasonic generator with variable frequency range from 10-15 kHz, 22-44 kHz, and 320.960 kHz, that differs in the following, that for the improvement of the procedure, reduction of costs and increase of its ecological purity, the cleaning of bottom-hole area from sediments and other colmatating impurities, is fulfilled by their dispersion and dissolving its the media of ultrasonic sound inside the active process fluid to modify the treatment products into a thin dispersed hydrophobic suspension with the size of solid particles from 0.5 to 20 Mk.
injection of a process fluid through this tubing into the bottom hole area of the pay, the run out of the tubing to the surface, the rim in (in the volume of process fluid in the interval under treatment) of the ultrasonic generator with variable frequency range from 10-15 kHz, 22-44 kHz, and 320.960 kHz, that differs in the following, that for the improvement of the procedure, reduction of costs and increase of its ecological purity, the cleaning of bottom-hole area from sediments and other colmatating impurities, is fulfilled by their dispersion and dissolving its the media of ultrasonic sound inside the active process fluid to modify the treatment products into a thin dispersed hydrophobic suspension with the size of solid particles from 0.5 to 20 Mk.
2. Procedure as per Claim # 1, that differ in the following, that like the active process fluid they use the liquid, possessing a low from 20 to 35 mPa/c-1 (erg/cm2), the magnitude of surface tension at the fluid-steam interface, density. That exceeds water gravity used is the flooding system (not less than by 100 kg/m3) and viscosity equal to viscosity of water phase or exceeding it by not more than 20 times.
3. Procedure as per Claims ## 1 and 2, that differs in the following, that like the active process fluid they use the mixtures (solutions) low viscosity oils (or refined petroleum products) and heavy non-polar liquid, tetrachlorinemethane, APK (TY 2122-199-05-7634-68-94) or 5-10 %
solutions of different surfactants (mainly non-ionogenic surfactants) in mineralized water with density, exceeding gravity of water, that is used is flooding system by not less than 100 kg/m3.
solutions of different surfactants (mainly non-ionogenic surfactants) in mineralized water with density, exceeding gravity of water, that is used is flooding system by not less than 100 kg/m3.
4. Procedure as per Claims ## 1, 2, 3, that differ in the following, that the establishing of optimum parameters of ultrasonic effect, upon the bottom-hole area is executed upon the basis of preliminary laboratory tests over the ultrasonic treatment of the sediments, withdrawn from the bottom-hole zone is one or another active process fluid, that gives thin dispersed hydrophobic suspension with the size of solid particles from 0.5 to 20 Mk.
5. Procedure as per claims ## 1, 2, 3, 4, that differ in she following, that like hydrophobic reagents of the surface of thin dispensed solid particles and the surface of the formation rock they use asphalt-wax and paraffin components (AWPC) of oil, that are in the residue, and that under the ultrasonic sound form is active process fluid molecular- and colloid-dissolved hydrophobic dispersed systems.
6. Procedure as per Claims ## 1, 2, 3, 4, 5, that differ in the following, that after bottom hole ultrasonic treatment there form thin dispersed hydrophobic suspension and its id used to level the injectivity profile of injection wells or create the hydrophobic water isolating barrier to limit the water influx in the production wells.
7. Procedure as per Claims ## 1, 2, 3, 4, 5, 6, that differ in the following, that under bottom hole ultrasonic treatment with slight sedimentation or wells that were treated previously by other procedures, for the formation of a thin dispersed hydrophobic suspension in a bottom hole zone, before ultrasonic treatments rue into well instead of active process liquid, they insect the dispersion of oil wastes (like bottom hale residues, that are formed in stock oil tank farm vessels), that are preliminary mixed-up with active process fluid at a pump (or in another mixer) in volume ratio, depending upon the constant of solid phase in oil wastes (from 1:10 to 1:15).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/RU1998/000423 WO2000015946A1 (en) | 1998-09-10 | 1998-12-21 | Method for oil field development |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2286245A1 true CA2286245A1 (en) | 2000-06-21 |
Family
ID=31885193
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002286245A Abandoned CA2286245A1 (en) | 1998-12-21 | 1998-12-21 | Method of oilfield development |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2286245A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105038746A (en) * | 2015-06-25 | 2015-11-11 | 西安石油大学 | Preparation method of jelly-type oily sludge profile control agent |
| CN107011882A (en) * | 2017-04-01 | 2017-08-04 | 陕西邦希化工有限公司 | High shale content content oily sludge deep electrical structure and preparation method and application |
| CN108929662A (en) * | 2018-08-08 | 2018-12-04 | 陕西友邦石油工程技术有限公司 | It is a kind of to carry the Profile Control in Injection Well technique that liquid prepares oily sludge blocking agent with cleaning |
| CN112576243A (en) * | 2019-09-30 | 2021-03-30 | 中国石油化工股份有限公司 | Method for predicting oil and gas reservoir pore blockage caused by suspended matters in injected water |
-
1998
- 1998-12-21 CA CA002286245A patent/CA2286245A1/en not_active Abandoned
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105038746A (en) * | 2015-06-25 | 2015-11-11 | 西安石油大学 | Preparation method of jelly-type oily sludge profile control agent |
| CN107011882A (en) * | 2017-04-01 | 2017-08-04 | 陕西邦希化工有限公司 | High shale content content oily sludge deep electrical structure and preparation method and application |
| CN107011882B (en) * | 2017-04-01 | 2020-12-08 | 陕西邦希化工有限公司 | High-argillaceous-content oil-containing sludge deep profile control agent and preparation method and application thereof |
| CN108929662A (en) * | 2018-08-08 | 2018-12-04 | 陕西友邦石油工程技术有限公司 | It is a kind of to carry the Profile Control in Injection Well technique that liquid prepares oily sludge blocking agent with cleaning |
| CN108929662B (en) * | 2018-08-08 | 2020-12-01 | 陕西友邦石油工程技术有限公司 | Water injection well profile control process for preparing oil-containing sludge plugging agent by using clean carrier fluid |
| CN112576243A (en) * | 2019-09-30 | 2021-03-30 | 中国石油化工股份有限公司 | Method for predicting oil and gas reservoir pore blockage caused by suspended matters in injected water |
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