Method and liquid for improvement of permeability of sandstone formations by chelating agent

FIELD: oil and gas industry.

SUBSTANCE: sandstone formation treatment method includes injecting into the formation a fluid containing 5-30% by weight of the total amount of glutamic liquid N,N-diacetic acid or its salt (GLDA), 0.1-2% by volume of corrosion inhibitor, 0.01-5 % by volume of surfactant and, optionally, a common solvent. The surfactant is a non-ionic or anionic surfactant and has a pH value of between 1 and 14.

EFFECT: improved permeability of sandstone formations, biodegradability and high acidity without the formation of processing fluid scale.

20 cl, 9 dwg, 3 tbl, 10 ex

 



 

Same patents:

FIELD: oil and gas industry.

SUBSTANCE: method includes drilling of horizontal wellbore in productive stratum with cementing of casing string, lowering of perforator to the horizontal wellbore at the pipe string and performance of perforated openings in the horizontal wellbore with azimuth upward direction, lowering of the pipe string with a packer to the well, setting of the packer, pumping of breakdown agent through the pipe string and formation of hydraulic cracks in the horizontal wellbore. The horizontal wellbore in productive stratum is drilled in parallel to direction of the maximum stress in rocks. Then perforator is lowered to the horizontal wellbore at coil tubing (CT) and perforation openings are made in the horizontal wellbore in one row, then CT is pulled out from the well with perforator, the perforator is dismounted and the CT is equipped from below with an inflatable packer. CT is lowered up to the bottomhole by axial movement of CT from the mouth to the bottom to distance of 50m with speed rate of 0.5m/min and simultaneous pumping of viscous gel with density exceeding density of water in volume sufficient for filling with the following acid viscoelastic composite, wt %: gelling agent 12.0; 22% hydrochloric acid (HCl) 22.5; fresh water 65.5; in lower part of the horizontal wellbore section per 2/3 of the horizontal wellbore diameter. The inflatable parker is set, hydraulic fracturing is performed by pumping the following thickened acid composite, wt %: gelling agent 12.0; 22% hydrochloric acid (HCl) 68.0; fresh water 20.0; with further filling with gelling fluid with decomposer of perforated openings in the upper part of the horizontal wellbore section per 1/3 of the horizontal wellbore diameter. The inflatable packer releasing is made; then hydraulic fracturing is performed in the remaining part of the horizontal wellbore; to this end the above operations are repeated starting from the CT axial movement from the mouth to the bottom up to filling of the treated interval with gelling fluid with decomposer. Upon completion of interval hydraulic fracturing the well is developed by swabbing, at that viscoelastic gel is diluted at contact with stratal fluids and unblocks drained parts of the horizontal wellbore and then removed from the well.

EFFECT: increased efficiency of crack development, improved quality of hydraulic fracturing, reduced time for hydraulic fracturing.

5 dwg

FIELD: oil and gas industry.

SUBSTANCE: method includes the detection of dependence between an adsorption layer structure and the concentration of non-ionogenic surfactant. The concentration of the surfactant in an aqueous solution of the non-ionogenic surfactant is accepted on the condition of formation of an "island" adsorption layer on the surface of the rock - alternating hydrophilic sections of an oil reservoir surface and hydrophobic sections of absorbed molecules of the surfactant providing for structuring of oil drops in the flow. A well is selected for the operation. Control measurements of yield, well head and bottom hole pressures are carried out. The wells are investigated at stabilised and transient conditions. An acid-containing solution is pumped to the well bottom hole. Then the acid-containing solution is removed from the well by well flushing with oil. Then a packer device is installed into the well. Further pumping of a water-removing composition is carried out, as well as the aqueous solution of non-ionogenic surfactant, displacing fluid into the production well. The well is soaked, and then oil is uptaken via production wells.

EFFECT: increased efficiency of treatment due to the development of a structured adsorption layer of surfactants in a bed.

1 ex, 5 tbl, 6 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention relates to compositions for wells treatment for use in oil industry. Composition for well treatment containing chemical for well treatment adsorbed using water-insoluble adsorbent, where composition is produced by the well treatment chemical deposition from liquid, at that the well treatment chemical is adsorbed on the water-insoluble adsorbent, and where the well treatment chemical is deposited upon metal salt presence. Well treatment liquid containing the above mentioned composition and carrying liquid. Method of the underground reservoir or wellbore treatment including the above mentioned well treatment liquid injection in the reservoir or wellbore. Method to monitor the well treatment chemical release in the wellbore including the above composition injection in the wellbore. Invention is developed in subclaims.

EFFECT: improved efficiency of treatment in environments with high pH.

38 cl, 3 dwg, 4 ex

FIELD: oil and gas industry.

SUBSTANCE: method of filter cake removal of bottom hole area of low-permeable low-temperature terrigenous reservoir located near the permafrost rocks comprises sequential injection through the column of oil-well tubing to the bottom hole area of mudded low-permeable low-temperature terrigenous reservoir of methanol in a volume of 1-2 m3 per 1 m of perforated thickness, phosphoric acid of 5-6% concentration with technological thermal equilibrium time of not more than 0.5 hours. Then aerated dispersed aqueous solution of hydrogen peroxide of low concentration of not more than 10-15 wt % is injected in the volume of 2-3 m3 per 1 m of the perforated thickness with forcing the orthophosphoric acid in a distal part of the reservoir. Then aerated dispersed aqueous solution of hydrogen peroxide is injected and forced again in the reservoir using the gas condensate with short-term technological thermal equilibrium time of not more than 0.5-1.0 h. Then removal and taking away of the remaining part of the aerated dispersed aqueous solution of hydrogen peroxide from the reservoir and the well to the surface is carried out. Then the well is developed by feeding to the well of inert gas, such as nitrogen, worked out, and the well is brought into production. At that injection of aerated dispersed aqueous solution of hydrogen peroxide is carried out by pulsed-cyclical method with alternate pumping the aqueous solution of hydrogen peroxide and inert gas, such as nitrogen.

EFFECT: increased permeability of dried bottom hole area of the reservoir, increase in the degree of filter cake removal of the bottom hole area and increase in productivity of the wells.

3 ex

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of bottom-hole zone of carbonate reservoir includes injection of the acid composition containing in wt %: inorganic or organic acid, or their mixture 9.0-24.0; zwitterion surface-active substance - oleinamidopropylbetaine 1.0-10.0; hydrophobically-modified polyurethane polymer 0.05-3.0; water - rest, at that the acid composition is injected by single stage or by portions with holding between injections. The acid composition can additionally contain anionic surface-active substance in amount of 0.1-3.0 wt %. The above specified acid composition is injected alternating with injection of hydrochloric acid at 12-24% concentration.

EFFECT: alignment of profile of inflow of the production wells in carbonate reservoirs with non-uniform permeability, creation of new fluid conducting channels through entire perforated thickness of the reservoir, restoration of reservoir characteristics of bottom-hole zone due to its cleaning of mud solid particles.

3 cl, 1 tbl, 16 ex, 4 dwg

FIELD: chemistry.

SUBSTANCE: method for interval acidising of a horizontal well using a carbonate reservoir, which includes lowering a pipe string into a well; pumping acid compositions into the formation through the pipe string; conducting geophysical investigations in the horizontal well before treatment; selecting and separating intervals of the horizontal well into two groups; the first group includes intervals with permeability of 40-70 mD and water cut of the extracted product of 70-80%; the second group includes intervals with permeability of 5-39 mD and water cut of the extracted product of 50-69%; lowering into the horizontal well a pipe string plugged at the bottom and fitted with two packers with a perforated connecting pipe in between; performing consecutive treatment of the intervals of the horizontal well relating to the first group by sealed cut-off of each interval with subsequent alternating pumping into each interval in three cycles a temporary blocking composition at a rate of 6-12 m3/h, the temporary blocking composition used being a water-in-oil emulsion with dynamic viscosity of 120 mPa·s at 20°C, and an acid composition at a rate of 54-66 m3/h; after treatment of the intervals of the horizontal well relating to the first group, retrieving the pipe string from the horizontal well; at the mouth of the horizontal well, the pipe string is fitted with a liquid pulsator above the perforated connecting pipe and the pipe string which is plugged at the bottom and fitted with two packers with a perforated connecting pipe in between is once more lowered into the horizontal well; treating the intervals of the horizontal well of the second group by sealed cut-off of each interval with subsequent pulsed pumping into each interval a self-deviating acid composition based on a gelling agent at a rate of 24-36 m3/h.

EFFECT: intensifying oil extraction from a horizontal well, increasing oil yield and reducing the water cut of the extracted product.

3 dwg

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of the oil reservoir includes geophysical survey in open horizontal wellbore to determine dislocations crossed by the bore in the reservoir, i.e. cracks, fractures, cavities, run in the horizontal wellbore on pipes string the filters with variable perforation density, packers installation, acid injection in horizontal wellbore, acid flush, well washing and commissioning. At that one packer is installed upstream the opened wellbore between the casing string and pipes string, and rest packers (expansing packers) are installed at places where the bore crosses dislocations. For each dislocation packer is selected with length exceeding width of the dislocation determined according to geophysical curves by at least 10 times. In pipes string hydrochloric acid with concentration 10-20% is injected on the basis 5-30 m3 per meter of oil-saturated reservoir thickness under wellhead pressure Pwh=(0.008…0.011)·H, MPa, where H is average depth of the reservoir, m. Perforation holes of filters are made round with diameter 5-10 mm, similar along the wellbore. Density of filters perforation for each section created between the packers, and between packer and bore end is increased linearly from zero at periphery to maximum in centre, in its turn this is determined via the hydrodynamical perfection coefficient as follows: k1h1Lnl1rc+С1=k2h2Lnl2rc+С2=...=knhnLnlnrc+Сn, where C1, C2, Cn are hydrodynamical perfection coefficients of the well as per character of opening on each nth section along the horizontal wellbore; l1, l2, ln are length of nth section, m; k1, k2, kn are average permeability of nth section, m2; h1, h2, hn are average oil saturated thickness of nth section, m; rc is well radius, m.

EFFECT: increased oil recovery of the reservoir due to increased reservoir coverage by action.

2 dwg, 2 ex

FIELD: oil-and-gas industry.

SUBSTANCE: oil field development method involves working fluid pumping in through the injection wells and formation products withdrawal through the retrieving wells. The oil field is developed with the established ratio of formation products withdrawal compensation through working fluid pumping in. The borehole zone is treated with acid in the injection wells. The oil field is developed with the newly established ratio of formation products withdrawal compensation through working fluid pumping in until approach of the displacement front, changed as the result of acid treatment, to the retrieving well. Hydrofracturing is performed in the retrieving well with withdrawal compensation recovered to the initial value after recovery of formation products water content changed as a result of hydrofracturing.

EFFECT: field oil yield increase.

1 ex

FIELD: oil and gas industry.

SUBSTANCE: invention is related to the technology intended for well productivity improvement. Large-volume selective acid treatment (LVSAT) for producers in carbonate reservoirs includes the injection to the well of an acid composite band with the specific volume of 1.5-3m3 per 1 m of an oil-saturated interval and non-linear viscous deflecting fluid before and/or upon the injection of the acid composite band, at that the injection of the acid composite is carried out with an optimal flow rate and an optimal ratio of a deflecting fluid volume to the acid composite volume, which are defined by mathematic modelling of the process considering changes in the wellhead and bottomhole pressure, type of the acid composite, type of the deflecting fluid, porosity and permeability of rock; at that for the purpose of the optimal flow rate optimisation for the acid composite injection dependencies of the optimal flow rate of injection on the specific volume of reagents injection are obtained with different constants of the reaction.

EFFECT: improved efficiency of large-volume selective acid treatment (LVSAT) for carbonate reservoirs.

2 cl, 5 tbl, 1 ex, 11 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: proposed process comprises lowering of flow string in hydrofrac zone and sealing of well annulus by packer. Rock is subjected to hydrofracturing to produce cracks by forcing gasified fluid via said flow string with the fracture propping. After sealing of casing string-borehole annuity packer is used to cool bottom hole zone by nitrogen gas with temperature of minus 40 to minus 45 degrees Centigrade. Then, hydrofrac is performed by injection of the mix of hydrochloric acid and nitrogen in amount sufficient for production of hydrochloric acid foam with foam content of 57% at well bottom. Then, 220°C superheated steam is forced via said flow string to hydrofracture. Note here that volume of said steam is selected to equal or to exceed that of forced hydrochloric acid foam and that of flow string. Now, the well is operated.

EFFECT: higher efficiency of fracturing.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: dry mixture for makeup of well-killing fluid containing industrial powdered lignin sulphonate, biopolymer of xanthane gum and bone glue with the following ratio of ingredients, wt %: the above lignin sulphonate 86.7-90.0, biopolymer of xanthane gum 9.5-12.5, bone glue 0.5-0.8.

EFFECT: improving impermeable properties of the well-killing fluid made of dry mixture having high stability during storage due to excluded caking and lumping, ensuring potential regulation of density of the well-killing fluid, reducing time and simplifying technology of well-killing fluid makeup of non-critical reagents, reducing time for well development, potential usage of the well-killing fluid at low climatic temperatures, expanding range of reagents, saving transportation costs.

2 cl, 1 tbl

FIELD: agriculture.

SUBSTANCE: method comprises deep loosening of soil, application of fertilizers and ferrous sulphate solution, and watering with increased irrigation rate. At that as the fertilizer the urea formaldehyde fertilizer is applied in the topsoil, which is saturated with ferrous sulphate solution and encrusted with phosphogypsum. After completion of washing the fertilizer is moved to the lower part of the ploughed horizon.

EFFECT: efficient desalination of irrigated saline soils with improvement of soil structure, increase in soil fertility and erosion resistance without damaging the surrounding area and plants.

FIELD: oil and gas industry.

SUBSTANCE: cement slurry contains 46.0-75.0 wt % of binding material and as such portlandcement of packing class G or cement mix Micro TSS BTRUO or a mix of aluminous cement GTS-40 and microcement Micro TSS BTRUO in mass ratio of 3:7, or a mix of aluminous cement GTS-40 and portlandcement PTST 50 in mass ratio of 1:4 is used; 1.0-4.0 wt % of surfactant and as such a mix of emulsifying agent MR-150 is used with calcium alkyl benzosulphonate and emulsifying agent OP-4 in mass ratio of 1:4:9; or a mix of emulsifying agent MR-150 is used with calcium alkyl benzosulphonate, water-repellent agent ABR and Neftenol VKS-N in mass ratio of 4:4:3:3; 9.0-27.0 wt % of diesel fuel; 0.0-0.5 wt % of calcium chloride; 0.0-2.0 wt % of condensed microsilica MK-85 and fresh water - the remaining share.

EFFECT: improved fluidity, reduced water loss, improved strength and durability of cement stone.

2 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to compositions and methods of wellbore processing. A composition for wellbore cleaning contains, wt %: solvent 10-45; cosolvent 10-40; hydrophilisating surface-active substance 5-10; purifying surface-active substance 5-20; non-ionogenic surface-active substance 1-10; non-ionogenic auxiliary surface-active substance 1-5; emulsifying surface-active substance 1-5; water liquid 1-5.

EFFECT: improvement of cement binding in the annulus space between the case pipe and the rock surface.

14 cl, 4 ex, 4 tbl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention relates to compositions for wells treatment for use in oil industry. Composition for well treatment containing chemical for well treatment adsorbed using water-insoluble adsorbent, where composition is produced by the well treatment chemical deposition from liquid, at that the well treatment chemical is adsorbed on the water-insoluble adsorbent, and where the well treatment chemical is deposited upon metal salt presence. Well treatment liquid containing the above mentioned composition and carrying liquid. Method of the underground reservoir or wellbore treatment including the above mentioned well treatment liquid injection in the reservoir or wellbore. Method to monitor the well treatment chemical release in the wellbore including the above composition injection in the wellbore. Invention is developed in subclaims.

EFFECT: improved efficiency of treatment in environments with high pH.

38 cl, 3 dwg, 4 ex

FIELD: oil and gas industry.

SUBSTANCE: lightweight plugging material contains cement PTsT-I-100, lightweight - expanded vermiculite, technical salt, chemical agent Crep, at the following ratio in wt %: cement PTsT-I-100 - 84.75; vermiculite - 9.42; Crep - 1.13; NaCl - 4.7. During the cement slurry preparation - expanded vermiculite, technical salt.

EFFECT: exclusion of the hydraulic fracture during wells cementation due to improved parameters of the packing cement, increased strength of cement stone at low and moderate temperatures at early stage of solidification upon simultaneous density reduction of the cement slurry.

1 tbl

FIELD: chemistry.

SUBSTANCE: reagent for treating drilling mud contains 94-96 wt % ferrochrome lignosulphonate and 4-6 wt % ammonium polyphosphate.

EFFECT: improved dilution properties of the reagent in salt mud, high thermal stability and environmental safety of the reagent.

3 tbl

FIELD: oil and gas industry.

SUBSTANCE: invention mainly relates to methods of hydrocarbons production from hydrocarbons containing reservoirs. Method of treatment of the reservoir containing crude oil including stages when: (a) composition is supplied to extract the hydrocarbons to at least part of the reservoir, at that the composition contains at least two internal olefin sulphonates selected from group comprising internal C15-18-olefin sulphonates, internal C19-23-olefin sulphonates, internal C20-24-olefin sulphonates and internal C24-28-olefin sulphonates, and at least one viscosity decreasing compound, that is isobutyl alcohol, ethoxylated C2-C12-alhohol, 2-butoxyethyl, butyl ether of diethylene glycol or their mixture, and (b) composition is provided with possibility to react with the reservoir hydrocarbons. Invention also relates to method of viscosity decreasing of composition of highly active surface-active substance and composition for hydrocarbons extraction.

EFFECT: result is creation of more effective method of hydrocarbons extraction from crude oil containing reservoir.

14 cl, 2 dwg, 2 tbl, 2 ex

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of bottom-hole zone of carbonate reservoir includes injection of the acid composition containing in wt %: inorganic or organic acid, or their mixture 9.0-24.0; zwitterion surface-active substance - oleinamidopropylbetaine 1.0-10.0; hydrophobically-modified polyurethane polymer 0.05-3.0; water - rest, at that the acid composition is injected by single stage or by portions with holding between injections. The acid composition can additionally contain anionic surface-active substance in amount of 0.1-3.0 wt %. The above specified acid composition is injected alternating with injection of hydrochloric acid at 12-24% concentration.

EFFECT: alignment of profile of inflow of the production wells in carbonate reservoirs with non-uniform permeability, creation of new fluid conducting channels through entire perforated thickness of the reservoir, restoration of reservoir characteristics of bottom-hole zone due to its cleaning of mud solid particles.

3 cl, 1 tbl, 16 ex, 4 dwg

FIELD: oil and gas industry.

SUBSTANCE: method of water production zone isolation in a well involves sequential injection of coagulation agent (25% solution of calcium chloride), buffer layer of fresh water, and Givpan acrylic reagent. Additionally, polyethylene terephthalate production waste product, PET with low polymerisation degree, is added to Givpan as a filler in amount of 18-24 wt %.

EFFECT: reduced core permeability.

1 dwg, 7 tbl, 3 ex

FIELD: production and exploratory well drilling, particularly foaming drilling fluids used during penetration through incompetent rock intervals and during primary productive oil and gas deposit opening in the case of abnormally low formation pressure.

SUBSTANCE: foam composition comprises surfactant, foam stabilizer, water, water hardness control additive and lubricant. The water hardness control additive is sodium silicate. The lubricant is VNIINP-117 emulsion. The foam stabilizer is polyacrylamide, the surfactant is sulphonole. All above components are taken in the following amounts (% by weight): sulphonole - 0.8-1.5, sodium silicate - 0.2-0.5, polyacrylamide - 0.1-0.5, VNIINP-117 - 0.5-2, remainder is water.

EFFECT: reduced power inputs for well drilling, as well as reduced coefficient of friction between drilling tool and well wall.

1 tbl

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