Method of preparation for cementing of wells drilled using invert-emulsion drilling mud

FIELD: mining.

SUBSTANCE: method of preparation for cementing of wells drilled using invert-emulsion drilling mud is characterised by the fact that casing column is lowered into the well and washed with invert-emulsion drilling mud; four flush fluids are pumped subsequently into the well: parting-displacement fluid, solvent fluid, washing fluid and displacement fluid, and their further forcing to behind-the-casing space with well cement mortar and flushing fluid with their complete displacement from the well and installation of well cement mortar in behind-the-casing space at the required interval; at that, mixture of invert-emulsion drilling mud with formation water and with organic solvent in volume ratio of (4-6):(2.5-5.5.):(0.5-1.5) respectively is used as parting-displacement flush fluid; mixture of organic solvent, tall oil and 40% of water solution of sodium hydroxide in volume ratio of (9.0-9.6):(0.2-0.5):(0.2-0.5) respectively is used as solvent flush fluid; water solution of detergent also acting as demulsifying agent with 0.5-4% mass concentration is used as washing flush fluid; light-weight cement slurry with density of 1.35-1.45 g/cm3 is used as displacement flush fluid. At that, rheological characteristics: plastic viscosity and dynamic shear stress of solvent flush fluid are higher than rheological characteristics of the previous one - parting-displacement fluid, and further washing flush fluid, and density and rheological characteristics of displacement flush fluid are higher than those of the previous one - washing flush fluid.

EFFECT: increasing the volume of dense contact of cement stone with enclosing surfaces.

4 cl, 1 ex, 3 tbl

 

The invention relates to the construction of wells, in particular to methods of preparation for cementing wells drilled in invert-emulsion drilling mud.

In connection with the increase in drilling wells with complex geological and technological conditions increases the number of wells, the transaction which is carried out with the use of invert-emulsion drilling fluid. Drilling on this mud provides quality wiring of the wellbore. This is due to its unique properties, high efficiency and well-known advantages over drilling fluids, water-based. The drilling fluid prevents the borehole from possible complications in the process of drilling-related landslides and rockslides rocks, saves the reservoir properties of the reservoir, allows you to keep the nominal diameter of the wellbore.

The problem is that the specified invert-emulsion drilling fluid (hereinafter EEC) is not compatible with liquids, prepared with water-based. As part IER dispersive environment presents a hydrophobic liquid. Therefore, preparation for cementing wells drilled in IER, is fundamentally different from those traditionally used. Displacement and washing the walls of the borehole from the drilling mud must be why apno to avoid traffic jams and deprecatively liquids. The presence on the walls of the borehole and casing oily residue invert-emulsion drilling fluid prevents the formation of a close contact of the cement with the breed and the column. To obtain a tight contact of cement with bearing surfaces and receiving sealed cement sheath in the annular space of wells drilled in invert-emulsion drilling fluid must be a comprehensive approach to drilling, preparation for cementing and cementing. Preparation for cementing wells drilled in IER, should provide combined chemical and mechanical effects on the remnants of the mud to ensure its complete removal from the walls of the borehole and casing pipes, without which it is impossible to obtain intimate contact of cement with bearing surfaces, it is necessary to form a sealed cement sheath in the annulus space.

The known method of preparing well for running and cementing casing, whose main task is receiving sealed cement sheath in the annular space (Patent RF №2144609). The method includes working out, flushing and cleaning of the borehole walls by the scraper device. After working wellbore spend processing mud, with whom IgA its static shear stress. Down the drill pipe, equipped with scraper devices. Clear previous casing from the wall structured clay mud. Further treated mud to properties achieved when the first treatment. Then produce a casing and cementing.

The disadvantage of this known method is that its application can provide debris removal only clay mud from the well, but to remove the remnants of invert-emulsion drilling fluid of the wells by using this method, it is impossible. The use of this mechanical method of exposure does not solve the problem of training of wells drilled in invert-emulsion drilling fluid, cementing, as this operation does not provide chemical effects on the residual solution, which would allow the transfer surface from a hydrophobic state to a hydrophilic, that is required for the formation of dense contact cement and contacting surfaces (rock, column).

Also known is a method of preparation of the well for cementing whose main purpose is to improve the quality of preparation for cementing wells drilled any type of water based mud (RF patent No. 2137906). Know the fair way is to establish on hole metasilicates baths, in the implementation of the consecutive injection of the following structures: viscoelastic separator, the composition of the powder, waterproofing-fixing composition and clogging of the composition. This increases the degree of substitution of the drilling fluid viscoelastic separator, a reduction in permeability of mud cake and increasing its resistance to the effects of cement mortar.

The disadvantage of this method is that this method can be used with any mud, but only water-based, and the application of this method with drilling fluids in non-aqueous basis, in particular, with invert-emulsion drilling fluids, it is impossible. As used in this way the buffer liquid bath and prepare water-based, during their contact with invert-emulsion drilling fluids in the mixing zone can be formed deprecatively tube, because getting into invert-emulsion drilling fluid of the aqueous phase leads to a dramatic thickening of the solution.

The known method of preparing the well for cementing (RF patent No. 2102581), whose goal is the improvement of quality of preparation of the well for cementing by improving its treatment at temperatures from 50 to 300°C. the Invention is that as the viscosity of the separator pump of naturalsound the first galvanic sludge production control density. As affinity filter cake obtained aqueous solution of waste manganese (II) nitrate (OMA). As abrasive washing liquid is injected aqueous solution OHMS with additives camerascamera slag production of ferrochrome with hematite.

The disadvantages of this method is the use of buffer fluid is water-based.

A known way of increasing the tension of the contact annulus of cement stone with the environment in the borehole (RF patent No. 2366800), according to which produce the casing, equipped with centralizers, dynamic effects on cavity upward flow of the buffer fluid and cement mortar. Dynamic effect is carried out by means of centralizers, each of which includes a housing made in one piece with the housing and directed spiral ribs. As the buffer fluid is selected liquid containing in its composition of the reactants with the properties of structured mud and adhesive film in the cavity. The quality of attachment is enhanced by the most effective technology for removal from the cavities structured mud and thick on the walls of cavities in the adhesive film.

The disadvantages of this method is the use of buffer fluid is water-based. the creating centrifugal forces upward flow can not solve the problem of preparation for cementing wells drilled in invert-emulsion drilling fluid, without sequential chemical effects on drilling fluid to transfer solution from a hydrophobic state to a hydrophilic.

The technical result achieved by the invention is to increase the close contact of the cement with bearing surfaces: casing - cement stone, cement stone is a rock in wells drilled with invert-emulsion drilling fluids, through the use of system buffer packs, the application of which the contacting surfaces of the walls of the borehole and casing pipes pass from a hydrophobic state to a hydrophilic, which provides a single condition of the contacting surfaces: cement stone with the borehole wall and the casing string.

This technical result is achieved by the proposed method of preparation for cementing wells drilled in invert-emulsion drilling fluid, whereby to produce a descent into the well casing pipe and rinse them invert-emulsion drilling fluids, perform sequential injection into the well of the four buffer liquids: separation-displacing, solvent, detergent and displacement, and subsequent displacement with them in the annulus t is nangnim cement mortar and squeezing the liquid with a full wipe them out of the borehole and installation of grouting cement in the annular space in the required interval, at the same time as the separation-preemptive buffer liquid, a mixture of invert-emulsion drilling mud, produced water and organic solvent in a volume ratio (4-6):(2,5-5,5.): (0,5-1,5) accordingly, as the dissolving buffer fluid is a mixture of an organic solvent, taly oil and 40%aqueous sodium hydroxide solution in a volume ratio(9,0-9,6):(0,2-0,5):(0,2-0,5) accordingly, as a detergent buffer liquid aqueous detergent solution, optionally having the properties of demulsifier, 0.5 to 4%of the mass concentration, as a preemptive buffer fluid - lightweight cement slurry density of 1.35-1.45 g/cm3and rheological characteristics: plastic viscosity and dynamic shear stress, dissolving buffer fluid exceeds the rheological characteristics of the previous - separation-preemptive, and the subsequent laundering, the buffer fluid, and the density and rheological characteristics of displacing the buffer fluid is higher than in the previous - laundering, the buffer fluid.

As the organic solvent used stable natural gasoline BGS, or organic solvents hydrocarbon FLACK, or MIA-PROM, or PT1-1U, or LOCATION.

As a cleanser, additionally the having the properties of demulsifier, use detergents DETERGENT, or NICK-4, or INMA, or SIDE-by-3.

As the reservoir water use water with a salinity of 1,02 g/cm3to 1.21 g/cm3.

Thus, we offer the technical result is achieved by the claimed method of preparation for cementing wells drilled in invert-emulsion drilling fluid, according to which before cementing in the well is pumped system buffer packets in sequence. In the target chemical impact of each buffer packs provided displacement, substitution, dissolution and washing of the bearing surfaces from the remnants of invert-emulsion drilling mud.

Separation-preemptive buffer fluid provides separation of the main volume of invert-emulsion drilling fluid from the aqueous buffer liquid and solvent, as well as the displacement from the well IER preserving the properties of the specified drilling fluid for later use. This is due to the fact that she has a relationship with the specified IER, and the organic solvent acts as a diluent and contributes together with reservoir water transfer mud from an inverse emulsion in line.

Dissolving buffer liquid consisting of a mixture of an organic solvent, taly Mac is a and 40%aqueous sodium hydroxide solution in a volume ratio(9,0-9,6):(0,2-0,5):(0,2-0,5) accordingly, provides for the dissolution of the residues specified mud on the walls of the borehole and the casing. With the dissolution occurs due to the presence in the composition of the hydrocarbon solvent. The viscosity of the solvent buffer fluid must be higher than the previous-separation-preemptive, and the subsequent laundering, buffer liquids to avoid surfacing in each previous and subsequent to reduce the amount of mixing contacting the buffer fluid - separating-preemptive, this - solvent and detergent buffer liquids.

Laundering buffer fluid which is an aqueous solution of 0.5-4%concentration of detergent, optionally having the properties of demulsifier, provides for the removal of dissolved residues of invert-emulsion mud from the walls of the borehole and the casing already means water-based, capable of dissolving the oily remains of mud.

Wipe the remnants of mud, previously uploaded buffer liquids, products dissolving and washing, is displacing the buffer fluid - lightweight cement mortar density of 1.35-1.45 g/cm3with the density and rheological characteristics (η=30 MPa·S.; τ0=50 DPA), surpassing its previous values of the buffer fluid to ensure olego eviction buffer liquids and residues of invert-emulsion drilling fluid from the well.

In addition, the injection of the specified buffer lightweight cement packs before grouting cement mortar is intended for formation on the walls of the borehole cement cover, ensuring the absolute affinity of the contacting materials (filtration cork - cement stone), ensuring good adhesion of the cement stone with the borehole wall (cement stone with the breed and column).

Thanks to this range of activities, their sequence and the specific recipe used a buffer of liquid is provided by tight contact of cement with bearing surfaces, which subsequently improves the quality of cementing wells.

The buffer fluid is used in the implementation of the proposed method in field conditions, prepare the containers cementing units as follows:

for the preparation of separation-preemptive buffer fluid in the capacity of the cementing unit is dialed estimated number of invert-emulsion drilling fluid (formulation, for example, described in patents of the Russian Federation No. 2336291, 2386657), which was used during the drilling of wells, and then injected produced water (e.g. salinity from 1,02 to 1.21 g/cm3and in the last turn (before being pumped into the well) is added an organic solvent, for example, BGS, is whether the MIA-PROM, or FLACK or PT1-1U, or LOCATION.

For the preparation of solvent buffer liquid into the container cementing unit dialed the estimated amount of the organic solvent, is then added taly oil, at least 40%aqueous NaOH solution, which, in addition to providing dilution capacity of the liquid is given to the desired consistency. Its rheological characteristics dissolving buffer fluid becomes more viscous than the previous and subsequent buffer fluid that helps to keep it from excessive mixing in contact with the buffer fluid. The need for this due to the low specific gravity of solvent buffer, which can cause intense mixing with the previous - separation-preemptive and the subsequent laundering of buffer liquids.

For the preparation of detergent buffer fluid in the capacity of the cementing unit is dialed estimated number of technical water, which dissolves the estimated number of special detergent, which may be, for example, DETERGENT, or NICK-4, or INMA, or SIDE-by-3.

Preparation and injection into the well preemptive buffer fluid - lightweight cement slurry density of 1.35-1.45 g/cm3directly before the process cementious is.

The order of injection of the buffer fluid in the borehole. First, second and third buffer fluid are injected sequentially in the process of preparatory works to cementing. The fourth buffer fluid is shut and pumped into the well immediately prior to cementation process, i.e. before grouting with cement mortar.

After injection of the fourth - preemptive, the buffer fluid (lightweight cement slurry in the well is pumped calculated volume of cement cement for cementing the annulus. After it is done downloading and squeezing the fluid in the computational volume. In this case, all pumped into the well buffer fluid must be displaced from the annulus of the well during produce and install in the desired interval, the estimated volume of grouting cement mortar.

Example. After the descent into the well casing pipes and washing her invert-emulsion drilling mud in the borehole consistently pumped prepared previously above buffer fluid, each of which performs its purpose. First upload separation-preemptive buffer liquid, prepared on the basis of invert-emulsion drilling fluid (for example, the recipe IER from the patent of the Russian Federation No. 2336291), produced water and the organic solvent stable natural gasoline, prepared in a volume ratio (5:4:1), respectively, in the volume of 6 m3in the capacity of cementing unit. Next, the solvent is pumped buffer fluid at a volume of 2.5 m3consisting of organic solvent-stable natural gasoline, taly oil and 40%aqueous sodium hydroxide solution. 1 m3an organic solvent is added to 50 l taly oil and 50 liters of 40%NaOH. This rheological characteristics: plastic viscosity and dynamic shear stress, dissolving buffer fluid (220 MPa·s and 180 DPA, respectively) exceed the rheological characteristics of the previous - separation-preemptive (29 MPa·s and 67 DPA, respectively) and the subsequent laundering, which is a Newtonian fluid. As organic solvents in the solvent composition of the buffer fluid, have a density less than 1.0 g/cm3so to prevent intensive mixing of detergent buffer fluid in the period of her in the well, dissolving the buffer fluid sagaseta (i.e. change the rheological characteristics of the fluid) using taly oil and lye. In fact, the reverse emulsion.

After dissolving the buffer fluid in the well is pumped laundering buffer liquid water based on laduma, in addition, demulsifying properties. This liquid is prepared in the tank cementing unit of 5 m3with the concentration of detergent, from 0.5 to 4%. The composition can be prepared on technical, brine or saline water. As the detergent used, for example, SIDE-by-3, with additional demulsifying properties.

Next injected displacing the buffer liquid in the form of a lightweight cement slurry density of 1.35-1.45 g/cm3for example, the following composition, wt.%: cement grouting 43.4 and water technical 56,6, which displaces from the annulus of the borehole remains of mud, buffer liquids, products dissolving and washing, and the density of 1.35-1.45 g/cm3) and rheological characteristics (30 MPa·s and 50 DPA) displacing the buffer fluid is higher than in the previous - laundering, the buffer fluid is a Newtonian fluid. Following this, the slurry is pumped grouting cement mortar (for example, patent No. 2191251, 2203389).

The proposed method was tested in field conditions in two wells Perm Perm drilled on IER. Comparison of the quality of cementing on the proposed technology preparation for cementing wells drilled in aqueous drilling fluids, the 2009 and at the preparation by known techniques for RF patent No. 2137906, are shown in table 1. The quality of cement is estimated density of contact cement stone with string and rock according to the ACC.

Table 1
MethodQuality contact cement
dense with breeddense with column
Offeris 83.887,9
Known from the patent of the Russian Federation No. 213790670,184,1

The data in table 1 show that the quality of cementing with the proposed technology of preparation of the well for cementing (for wells drilled on EEC) with the breed and the column is better than the quality of cementing preparation by known techniques.

Also in laboratory studies determined the degree of recovery of the permeability of ceramic disks, which were judged on the effectiveness of the proposed buffer liquids. The tests were carried out as follows. Through oxide disc (bronzemist the Yu 0,4 Darcy) in dynamic mode with a speed of rotation n=45 8-465 rpm filtered invert-emulsion drilling fluid. Then in the dynamic mode with the same speed filtered first buffer liquid for 10 minutes, then the second buffer liquid for 10 minutes, after which the filtered third buffer liquid for 10 minutes. After drying oxide disk check its permeability. Define the coefficient of restitution permeability oxide disk:

where KCE- recovery coefficient of permeability, %;

K1- the initial permeability of the oxide disc, MD;

K2- the final permeability of the oxide disc, MD.

In the tests used the following components of buffer liquids:

organic solvent:

- the stable natural gasoline on TO-1340-89;

- FLACK THAT 2458-01624084384-2006;

MIA-PROM THE 245801127913102-2001;

RT U THE 2458-004-50639090-2004;

water - soluble detergents:

- THE detergent 2458-038-40912231-2006;

- NIKA-4 TU 2499-014-12910434-2003;

- INMA THAT 2316-018-50003914-2005;

- SIDE-by-3 TU 2149-055-41805307-99;

- taly oil THAT 13-00281074-26-95;

- sodium hydroxide (NaOH) GOST 2263-79;

- produced water density 1,02; 1.15 and 1.20 g/cm3.

For tests used a buffer fluid, the composition of which is given in table 2.

When trials investigated the influence of the filing of the buffer fluid in the formation permeability ceramic disks. Data obtained during the laboratory tests are shown in table 3.

The data in table 3 show that only when the claimed sequence of injection of buffer liquids is ensured successful implementation of the proposed method of preparation for cementing wells drilled in IER.

Thus, studies have shown that the proposed method provides high-quality preparation for cementing wells drilled IER, since this provides the greatest amount of contact cement with bearing surfaces (rock, casing).

In addition, a hydrocarbon solvent, removing the remains of the EEC from the walls of the wellbore, preparing the wellbore subsequent to its development, preventing the possibility of education in the stalk part of the productive part of the wellbore emulsions that are difficult to remove in the process of completion.

1. Method of preparation for cementing wells drilled in invert-emulsion drilling fluid, characterized in that make the descent into the well casing pipe and rinse them invert-emulsion drilling fluids, perform sequential injection into the well of the four buffer liquids: separation-displacing, solvent, detergent and displacement, and subsequent displacement with them in the annulus grouting cement restoreme and squeezing the liquid with a full wipe them out of the borehole and installation of grouting cement in the annular space in the required interval, at the same time as the separation-preemptive buffer liquid, a mixture of invert-emulsion drilling mud, produced water and organic solvent in a volume ratio (4-6):(2,5-5,5):(0,5-1,5) accordingly, as the dissolving buffer fluid is a mixture of an organic solvent, taly oil and 40%aqueous sodium hydroxide solution in a volume ratio(9,0-9,6):(0,2-0,5):(0,2-0,5) accordingly, as a detergent buffer liquid aqueous detergent solution, optionally having the properties of the demulsifier, 0.5 to 4%of the mass concentration, as a preemptive buffer fluid - lightweight cement slurry density of 1.35-1.45 g/cm3and rheological characteristics: plastic viscosity and dynamic shear stress, dissolving buffer fluid exceeds the rheological characteristics of the previous - separation-preemptive, and the subsequent laundering of the buffer fluid, and the density and rheological characteristics of displacing the buffer fluid is higher than in the previous - laundering buffer fluid.

2. The method according to claim 1, characterized in that the organic solvent used stable natural gasoline BGS, or organic solvents hydrocarbon FLACK or MIA-PROM, or PT1-1U, or LOCATION.

3. With whom persons according to claim 1, characterized by the fact that as a detergent, optionally having the properties of demulsifier, use detergents DETERGENT, or NICK-4, or INMA, or SIDE-by-3.

4. The method according to claim 1, characterized in that as the reservoir water use water with a salinity of 1,02 g/cm3to 1.21 g/cm3.



 

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1 ex, 2 tbl

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1 ex, 2 tbl

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of drilling oil and gas vertical and inclined wells under difficult geological conditions. In the method for construction of deep wells under difficult mining and geological conditions with application of thin clay drilling muds of the following composition, wt %: clay 4.0-7.0, carboxymethyl-cellulose 0.5-2.0, sodium or potassium chloride 2.0-15.0, calcium carbonate 3.0-7.0, water - balance; or of the following composition, wt %: clay 4.0-7.0, carboxymethyl cellulose 1.0-3.0, sodium or potassium chloride 2.0-15.0, calcium carbonate 5.0-12.0, water - balance; drilling of geological elements that differ in complexity along a well length is carried out with one composition of a drilling mud, besides, tunnelling of filtering rocks is performed with account of preservation of natural permeability of productive reservoirs, elimination of inflows of a reservoir fluid into a well due to cooldown of a thin clay mud by 15-25°C with simultaneous increase of pressure in it by 3-6% from the mining one.

EFFECT: invention provides for stability of geological elements in tunnelling of wells, prevention of processes of drilling muds (fluids) absorption, inflows of a reservoir fluid, preservation of natural permeability of productive reservoirs by 80-90% from the initial values.

FIELD: chemistry.

SUBSTANCE: proppant is a material in form of particles, where each particle contains a proppant particle base, a water-soluble outer coating deposited on said base, and microparticles of an insoluble reinforcing and filling agent, at least partially immersed in the water-soluble outer coating such that said microparticles are essentially released from the proppant particle base when the water-soluble coating dissolves or breaks down. The material in form of particles for improving operation and/or efficiency of a bore hole in an underground formation, having a particle base from the underground formation, a water-soluble outer coating on said base and a reinforcing agent from microparticles at least partially immersed in said coating such that it is essentially released when the water-soluble coating dissolves or breaks down. The method of improving operating characteristics of a bore hole in an underground formation, involving feeding said material into one or more objects selected from an underground formation, a well shaft in said formation or bore hole in said underground formation.

EFFECT: high strength and wear-resistance of the proppant and permeability of the filling made from said proppant.

18 cl, 1 ex, 1 tbl, 4 dwg

FIELD: oil and gas production.

SUBSTANCE: method of formation face zone development consists in pumping the gas-generating and acid-based reagents, where gas-generating reagent is the compound that includes, wt %: urea 28.4-38.4, sodium nitrite 18.2-27.6, water - the rest, and acid-based reagent is the compound that includes, wt %: inorganic acid 5.2-60.9, surface acting agent 2.4-3.5, ferrum inhibitor 1.4-2.3, flotation agent 7.0-11.4, water - the rest. Note that the proportion of gas-generating and acid-based reagents amounts 1:(1-3), after pumping of the reagents they are held.

EFFECT: increase of injection capacity of intake well and influx to the producing wells, start of development of leak-proof zones not covered by influence.

3 cl, 2 tbl, 2 ex, 1 dwg

FIELD: oil and gas production.

SUBSTANCE: method of formation face zone development consists in pumping the gas-generating and acid-based reagents, where gas-generating reagent is the compound that includes, wt %: urea 28.4-38.4, sodium nitrite 18.2-27.6, water - the rest, and acid-based reagent is the compound that includes, wt %: inorganic acid 5.2-60.9, surface acting agent 2.4-3.5, ferrum inhibitor 1.4-2.3, flotation agent 7.0-11.4, water - the rest. Note that the proportion of gas-generating and acid-based reagents amounts 1:(1-3), after pumping of the reagents they are held.

EFFECT: increase of injection capacity of intake well and influx to the producing wells, start of development of leak-proof zones not covered by influence.

3 cl, 2 tbl, 2 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: composition for acid treatment of bottom-hole formation zone contains the following in wt %: mixture of a disodium salt of sulphoamber acid monoesters and alkylphenol ethoxylates based on propylene trimers, produced under the industrial name SOP-10n, 0.25-2.0, hydrochloric acid in terms of hydrogen chloride 10.0-24.0, water being the balance. The invention is developed in subclaims.

EFFECT: preventing formation of asphalt-resin deposits, reduced corrosiveness of the composition, reduced rate of dissolution of carbonate rocks, high surface activity on the boundary with oil, improved oil-washing properties and high penetrating power of the composition.

3 cl, 1 tbl

FIELD: chemistry.

SUBSTANCE: drilling agent is obtained by treating lignosulphonate with sulphuric acid and alkaline metal bichromate to pH 1-1.5, followed by partial neutralisation with sodium hydroxide to pH 4-5 and drying. During treatment, elementary sulphur is fed into the reaction zone in amount of 0.8-1.2 wt % of the weight of the lignosulphonate.

EFFECT: invention enables to obtain a drilling agent with high quality factors, avoid contamination of waste water with hexavalent chromium compounds.

1 ex, 1 tbl

FIELD: chemistry.

SUBSTANCE: drilling agent is obtained by treating lignosulphonate with sulphuric acid and alkaline metal bichromate to pH 1-1.5, followed by partial neutralisation with sodium hydroxide to pH 4-5 and drying. During treatment, elementary sulphur is fed into the reaction zone in amount of 0.8-1.2 wt % of the weight of the lignosulphonate.

EFFECT: invention enables to obtain a drilling agent with high quality factors, avoid contamination of waste water with hexavalent chromium compounds.

1 ex, 1 tbl

FIELD: oil-and-gas production.

SUBSTANCE: proposed method grinding raw mix, pelletizing fine batch, sieving preset-size granules, their drying, annealing and classification. Batch pelletising is performed in turbine mixer for 6-35 s at high-intensity circular motion of bulk that ensures normal acceleration of particles to 500-2500 m/s2 with batch moistening for 50-90% of normal level, and, after maturing for 0.5-6 min, granules are shaped to required sphericity in dish noduliser with addition of remaining amount of moistening solution. Proposed invention is developed in dependent claims.

EFFECT: higher yield and strength.

4 cl, 4 tbl

Up!
Table 3
no experienceThe processing sequence of the drives buffer fluidsRestore the permeability of the ceramic disks. KCE, %
1I(1)+II(1)+III(2)97,2
2I(2)+II(2)+III(1)90,5
3I(3)+II(4)+III(3)for 95.3
4I(2)+II(3)+III(3)for 93.4
5I(4)+II(3)4-III(4)91,7
6II(1)+I(2)+III(1)50,3
7III(2)+II(1)+I(1)5,2
Note: I - dividing-preemptive buffer liquid; II - dissolving buffer liquid; III - laundering buffer liquid. In parentheses shows the compositions of table 2.