Hydraulic fracturing method for low-permeable bed with clay layers and bottom water
FIELD: oil and gas industry.
SUBSTANCE: method includes running of production string with packer in to the well, setting of the packer, hydraulic fracturing by injecting fracturing fluid through production string with packer to the producing reservoir with further proppant injecting through perforated interval in the low-permeable bed, pressure releasing from the well. Additionally perforated interval in the low-permeable bed is isolated temporary, the interval of clay layer is perforated using alternating charges of large diameter and deep invasion; then the production string with packer is lowered so that the lower end of the production string is at the level of clay layer roof, the packer is set in the well, the low-permeable bed is fractured with formation of cracks by injection of fracturing fluid along the production string through perforated intervals in clay layer. Then bank of oil-based cross-linked gel is injected to cracks in volume of 3-5 m3 with flow rate of 10 m3/min. Proppant moisture is used as proppant. Then cracks are reinforced by dosed injection of fracturing fluid and proppant mixture starting with concentration of 400 kg/m3 for proppant mixture with stepped increase of its concentration in fracturing fluid per 200 kg/m3 for each dose and flow rate of 5 m3/min. The proppant mixture is made at the wellhead with the following ratio of components, wt %: proppant 12/40 mesh - 30%; proppant 18/20 mesh - 30%; quartz flour - 40%. Upon completion of hydraulic fracturing of low-permeable bed temporary isolation is removed from the perforated interval of the low-permeable bed with formation of hydraulic connection between the borehole and created fracture.
EFFECT: improved reliability of hydraulic fracturing for low-permeable bed with clay layers and bottom water.
The invention relates to the field of oil and gas industry, in particular can be used for hydraulic fracturing of low-permeability formation containing clay interbed with the underlying aquifer.
The known method of hydraulic fracturing in low permeability subsurface layer (patent RU No. 2402679, IPC E21B 43/26, publ. 27.10.2010, bull. No. 30), including the pumping of hydraulic fracturing fluid containing proppant particles through the borehole into the fracture created in the underground reservoir, wherein during injection, provide a turbulent flow of the fluid in the fracture through the injection of hydraulic fracturing fluid with a viscosity of less than 0.01 PA·s at a download speed of at least 8 m3/min, and the liquid contains particles of proppant, the radius of which is determined by calculation, in this pre-injection is carried out in the well-viscosity hydraulic fracturing fluid containing a proppant, and after the injection of hydraulic fracturing fluid with proppant particles pumped into the fracture slurry of a proppant coated rubber shell.
The disadvantages of this method are:
- first, the low reliability of conduct hydraulic fracturing associated with the injection of proppant calculation of the radius, and the error in the calculation may result in the inability to produce of proppant in the fracture and its clamping;
secondly, breakthrough cracks in the presence of bottom water during hydraulic bursting through the perforated intervals of low-permeability reservoir, causing sudden flooding of the well.
The closest in technical essence is a method of hydraulic fracturing in low-permeability layer with clay interlayers (patent RU No. 2457323, IPC E21B 43/26, publ. 27.07.2012, bull. No. 21), including injection through a hole in the column tubing (tubing) with the packer in the reservoir hydraulic fracturing fluid, followed by injection of proppant, wherein the hydraulic fracturing fluids used a foam system, water-based, containing: 55-75% nitrogen, 1% solution of potassium chloride and an aqueous solution of a surfactant, the process of hydraulic fracturing, folded from a productive and impermeable interlayers, starting at an initial density foam system 0.25 g/cm3which , with the help of the device for injection of hydraulic fracturing fluid with proppant serves on the tubing string in the bottomhole formation zone (PPP) with a gradual increase of pressure injection up to a maximum, and the maximum pressure created in the process of hydraulic fracturing, must be higher than the pressure of the hydraulic fracturing of the productive inter-layers, but below the fracturing pressure of clay layers in the PPP form of a hydraulic fracture in long�di - productive interlayers with the lowest critical fracture gradient, and then produce the fastening of hydraulic fractures by injection foam system with proppant, which is used as the silica sand with a concentration of sand in the foam system from 800 to 1000 g/l to increase the final density of the foam system to 0.8 g/cm3upon completion of the fracturing borehole close to the technological pause for 30 min, and at the wellhead in the composition of the tubing set adjustable choke and produce testing of wells on the spout, regulation fitting reach to spout when the pressure in the tubing string below the pressure when closing the bore at least 1.5-2 MPa.
The disadvantages of this method are:
- first, the low reliability of the method associated with a high likelihood of premature "stop", as fixing cracks is carried out with a high concentration of proppant - quartz sand in a foam system from 800 to 1000 g/l to increase the final density of the foam system to 0.8 g/cm3under these conditions, the transport capacity of the liquid carrier (foam) is sharply reduced, which can clog up the crack in the bottom hole formation zone;
- secondly, the low conductivity of the fracture in the low-permeability layer associated with uneven distribution�education quartz sand in the crack (mostly at the beginning of the crack) when it produce, which leads to a rapid closing of cracks and loss of conductivity;
- thirdly, breach cracks in the presence of bottom water during hydraulic bursting through the perforated intervals of low-permeability reservoir, causing sudden flooding of the well.
Technical objectives of the proposal are to improve the reliability of the method, increasing the conductivity of the fractures in low-permeability reservoir due to the uniform distribution of proppant in the fracture portion by injection and produce proppants mixture into the crack with a step increase in its concentration, and the exclusion of blowout fractures in the reservoir with bottom water in the process of hydraulic fracturing through the creation of a hydraulic fracture in an interval of clay interbed.
The tasks are solved by the method of hydraulic fracturing in low-permeability reservoir with the clay interlayers and plantar water, including the descent of the column tubing - tubing - packer into the well, the packer landing, conducting hydraulic fracturing is injected through the well on the tubing string with a packer into the reservoir hydraulic fracturing fluid, followed by injection of proppant through the perforated interval of low-permeability reservoir, bleed pressure from the well.
What is new is that additionally produce temporary isolation of the perforated interval nor�copernicanae layer, perforated interval of clay interbed with the use of alternating charges of large diameter and deep penetration, then pull the tubing with the packer in the well so that the lower end of the tubing was at the level of the roof of clay interbed, carry out the planting of the packer in the well, produce low-permeability fracturing the formation with the fracturing of the injection of hydraulic fracturing fluid along the tubing string through the perforated intervals of clay interbed, then pumped into the cracks trim cross-linked gel hydrocarbon based in the amount of 3-5 m3a flow rate of 10 m3/min, and as the proppant used proppant mixture, and then produce the fixing cracks in portions injection of hydraulic fracturing fluids and proppants mixture, since the concentration proppants mixture of 400 kg/m3with a step increase in its concentration of 200 kg/m3in hydraulic fracturing fluid in each serving and a flow rate of 5 m3/min, and proppanow the mixture is prepared at the wellhead in the following ratio, wt.%:
the proppant 12/40 mesh. - 30%;
the proppant 18/20 mesh. - 30%;
- quartz flour - 40%,
at the end of the low-permeability fracturing of the reservoir removes the temporary isolation of a perforated interval the low permeability of the reservoir and carry out the perforation of the low-permeability layer with the formation of hydraulic�coy communication between the wellbore and hydraulic fracture.
This method is applied in oil and gas wells in low-permeability layers (with permeability (0.1 to 10)×10-3μm2and sandstones containing interlayers vysokonapornaya or migrating clays and plantar water.
The proposed method is as follows.
The figure schematically shows the proposed method of hydraulic fracturing in low-permeability reservoir with the clay interlayers and plantar water, where 1 - producing well; 2 - low-permeability layer; 3', 3" - impermeable interlayers (clayey interlayers); 4 - productive interlayer (permeable Sandstone); 5 - the perforated interval is productive of the interlayer 4, 6 - layer with plantar water; 7' and 7" - perforations, respectively, of large diameter and deep penetration; 8 - column tubing; 9 - packer; 10 - a bolt; 11 - discharge line; 12 - hydraulic fracture; 13 - cushion-crosslinked gel; 14 - the perforated interval is productive of the interlayer after the fracturing of the formation fluid communication between the wellbore and hydraulic fracture.
Production well 1 (see figure), which revealed a low-permeability layer 2 (the layer) with impermeable interlayers (clay interlayers) 3' and 3", between which are placed the productive zone (permeable Sandstone) 4 low permeability ((0,1-10)×10-3MK� 2), with a perforated interval of 5 and a reservoir with bottom water 6 is operated, for example, sucker rod pump (figure not shown). In the operation flow in a producing well 1 is declining rapidly, in connection with the work required for enhanced recovery of oil from the reservoir 2 producing well 1.
To this end produce hydraulic fracturing (fracking) of the productive zone 4 of the reservoir 2. This is removed from the well operational equipment (figure not shown).
Produce temporary isolation of the perforated interval 5 (see figure) of the reservoir 2. To do this, pull on the technological pillar of the pipes (figure not shown) and installed in a borehole 1 above the perforated interval 5 layer 2 (see figure) retrievable packer-tube (IPP) to 35 MPa (figure not shown) construction of TatNIPIneft, Bugulma, Republic of Tatarstan), then technological pipe string is lifted out of the borehole 1.
Then in the borehole 1 is lowered the hammer on the column technological pipes and perforated interval of clay interbed 3' using alternating charges with the formation of the perforations large diameter 7' and deep penetration 7". For example, using punch PCTL-M, produced by Neftekamsk machine-building plant (the town of Neftekamsk, the Republic of�face of Bashkortostan, Russia).
Create a stripe perforation of the large-diameter holes 7' and deep penetration 7" in the range of clay interbed 3' allows you to create directions for the formation of cracks 12 in the productive zone 4 through clay interbed 3' and exclude breakthrough cracks in the reservoir with bottom water 6.
Then run into the well column 1 pump-compressor pipes 8 with the packer 9. Make landings packer 9 in the well 1 above the perforations large diameter 7' and deep penetration 7". Thus, carry out the sealing annulus area of the tubing string 8. As the packer is used, for example, with a mechanical packer axial installation P-YAMO (35 MPa) manufactured by scientific-production firm "Packer" (Oktyabrsky, Republic of Bashkortostan, Russia).
At the wellhead 1 at the upper end of the tubing string 8 is wrapped around the valve 10, through which the discharge line 11 tied with pump units (figure not shown) for pumping of hydraulic fracturing fluid.
Determine the total volume of hydraulic fracturing fluid according to the following formula:
where Vg- total volume of hydraulic fracturing fluid, m3;
k=11-12 - transfer coefficient, m3/m, we assume k=11;
Np- the height of the perforated interval of the productive zone 4 PLA�TA 2, M.
In this formula conversion factor obtained empirically and depends on the physico-chemical properties of the reservoir 2, which produces hydraulic fracturing.
For example, the height of the perforated interval of the productive zone 4 of the reservoir 2 is equal to 3 m. Substituting the values into the formula Vg=k·Hpreceived total volume hydraulic fracturing fluids:
As a hydraulic fracturing fluid used known compounds linear gels, for example, developed by ZAO Himechan" having a trade name "Himeko-N (TU 2481-053-17197708), Himeko-T (TU 2481-077-17197708-03), Himeko-IN" (TU 2499-038-17197708-98). Before you fix a linear gel into the well in it add the inhibitor SLP-55 Scale Inhibitor manufactured by Halliburton (2% of the total linear gel) that prevent clay swelling (impermeable interlayers 3' and 3") in the process of hydraulic fracturing.
With the help of pump units on the discharge line 11 through the open valve 10 is pumped into the well 1 to the tubing string 8 the hydraulic fracturing fluid - linear gel with a dynamic viscosity of, for example, 30 SP. The hydraulic fracturing fluid is pumped with a flow rate of, for example, 7.0 m3/min hydraulic fracturing fluid passing through the perforations of large diameter 7' and deep penetration 7", puts pressure on the clay interbed 3' of the reservoir 2, the gap� it, as evidenced by the drop in pressure pumping and increasing the injectivity of the reservoir 1 with the formation of the fracture gap 12 in the productive zone 4. For example, when downloading a linear gel has reached a pressure of 30 MPa, due to the formation of the fracture gap 12 there was a drop in pressure pumping linear gel at 25%, i.e. to 22.5 MPa, and the injectivity of the reservoir 1 has increased by 30%, for example from 7.0 to 9.1 m3/min.
The use of linear gel (30 SP) creates less resistance due to the relatively low viscosity. In the process of crack formation 12 through the column pipe into the reservoir 1 was injected gelled fracturing fluids - linear gel in volume, for example, 18 m3.
Later in the crack 12 using a pump units pump trim cross-linked gel in the amount of 3-5 m3for example , in the amount of 4 m3on the discharge line 11 through the open valve 10 to the column pipe 8 and through the perforations of large diameter 7' and deep penetration 7" clay interbed 3' layer 2 with a flow rate of 10 m3/min.
As a fringe crosslinked gel hydrocarbon-based use of any known composition, for example, see Chapter 3 of the monograph S. A. Ryabokon "Technological fluids for well completion and workover (JSC NPO Burenie, 2006, p. 153), which comprises a solution of polymer (MO-HT) in the hydrocarbon stitching and�variable item destructor (MO-NT-hydrophobic modification PAA) My-T-Oil (Halliburton) or cross-linked gel hydrocarbon-based, made the company CJSC "Fromhim-Sphere" (Moscow, Russia).
As the proppant used propanol mixture. Cross-linked gel hydrocarbon-based has a low pressure loss by friction in the pipes and high viscosity in the reservoir, which ensures the creation of a wide, deep cracks during the degradation does not form a precipitate, affect the permeability of the formation fracturing and crack, and is characterized by high pescaderia properties, low filterability in the reservoir and good pumpability.
Cross-linked gel is deposited on the bottom of the crack 12 and forms a kind of cushion 13, which, on the one hand, prevents the development of cracks break down and next mount proppants mixture into the reservoir with bottom water 6, and on the other hand, reduces the linear filtering of gel in the lower clay interbed 3" that allows you to evenly fill the crack 12 proppants mixture.
Then at the wellhead prepare propanol mixture in the following ratio (% wt.):
the proppant 12/40 mesh. - 30%;
the proppant 18/20 mesh. - 30%;
- quartz flour fractions of 0.1 mm to 40%.
For example, cook 9·103kg = 9 t proppants mixture. For this tank (figure not shown) was charged and mixed proppant mixture in the following ratio (% wt.):
the proppant 12/40 mesh. - 30% (2,7·103kg);
the proppant 18/20 mesh. - 30% (2,7�10 3kg);
- quartz flour fractions of 0.1 mm to 40% (3,6·103kg).
Use the proppant fractions 12/40 and 18/20 mesh., which are made according to GOST R 51761-2005 "aluminosilicate Proppants. Technical conditions" and let Borovichevsky the refractories plant (Borovichi, Republic of Belarus). Quartz flour fractions of 0.1 mm produced by THE 5717-001-16767071-99, supplier LLC Trading house "Quartz" (Ekaterinburg, Russia). With the help of pump units on the discharge line 11 (see the figure) through the open valve 10 is pumped into the well 1 to the drill pipe remaining volume 8 (33 m3-18 m3=15 m3) hydraulic fracturing fluid - linear gel with a dynamic viscosity of, for example, 30 JV with the addition of proppant in the amount of 9 T. the hydraulic fracturing fluid with proppants mixture is injected into the crack 12 through the perforations of large diameter 7' and deep penetration 7" at a rate of 5.0 m3/min with a step increase in the concentration proppants mixture in a linear gel. Linear gel as a fluid carrier compared to the foam used in the prior art, has the best transporting propanol a mixture of ability that allows you to produce uniform arrangement of proppants mixture in the crack 12. Use as a proppant is not quartz sand, as described in the prior art, and proppants mixture, comp�of the present from the proppant different factions, provides high conductivity of the crack 12 formed in the low-permeability layer, and prevents its closure.
The concentration proppants mixture in a linear gel increases so that when produce last (but not before) the portions of proppant happened "stop" will be indicated by a sharp increase in the pressure of injection. Increase the concentration proppants mixture in a linear gel at 200 kg/m3in each successive portions, since the concentration proppants mixture in a linear gel 400 kg/m3.
Number of servings depends on the mass proppants mixture intended for fixing cracks 12 of calculating the increase in the concentration proppants mixture in a linear gel at 200 kg/m3in each successive portions, since the concentration proppants mixture in a linear gel 400 kg/m3.
For example, the pumping of linear gel is produced in three portions 15/3=5 m3i.e. by 5 m3in each portion, wherein each portion of the linear gel add proppant mixture, respectively first 2 t = 2000 kg proppants mixture (concentration of 2000 kg/5 m3=400 kg/m3), then 3 t proppants mixture (concentration of 3000 kg/5 m3=600 kg/m3and in the last portion of the linear gel add 4 t proppants mixture (concentration of 4000 kg/ 5 m3=800 kg/m3).
Total pumped and forced 9 t proppants mixture in CRA�well 12.
In this case, when produce last portion proppants mixture under a pressure of 22.5 MPa will be a sharp pressure jump injection 40%, i.e. up to 31.5 MPa. After produce last portion proppants mixture is produced technological extract, for example for 2 h, pressure decay, then tear packer 9 and removed from the well the tubing string 8 with the packer.
Increases the conductivity of the crack 12 in the low-permeability layer due to the uniform distribution proppants mixture in the fracture portion by injection and produce proppants mixture into the crack with a step increase in its concentration.
Removes the temporary isolation layer 2. For this lowered into the borehole technological pipe string with a standard device, such as external rublevkoy, make the capture of the IPP. Then remove technological pipe string with rublevkoy and STIs to the surface.
Next spend perforation 14 of the productive zone 4 low permeability of the reservoir formation fluid communication between the wellbore 1 and 12 crack propagation. For example, in the well 1 on the column technological pipes pull the hammer PCTL-M, produced by Neftekamsk machine-building plant (the town of Neftekamsk, Republic of Bashkortostan, Russia), and is perforated interval of the productive zone 4 of the reservoir 2 with the use of deep charges�wow penetration.
The proposed method allows you to:
to increase the reliability of holding low-permeability fracturing of a formation with clay interlayers and plantar water;
- to increase the conductivity of fractures in low-permeability reservoir due to the uniform distribution proppants mixture in the fracture portion by injection and produce proppants mixture into the crack with a step increase in its concentration;
- delete breakthrough cracks in the reservoir with bottom water in the process of hydraulic fracturing through the creation of a hydraulic fracture in an interval of clay interbed by preliminary perforation with the use of alternating charges of large diameter and deep penetration.
Method of hydraulic fracturing in low-permeability reservoir with the clay interlayers and plantar water, including the descent of the column tubing - tubing - packer into the well, the packer landing, conducting hydraulic fracturing is injected through the well on the tubing string with a packer into the reservoir hydraulic fracturing fluid, followed by injection of proppant through the perforated interval of low-permeability reservoir, bleed pressure from the well, characterized in that additionally produce temporary isolation of the perforated interval low-permeability layer, perforated interval of clay interbed with the use of alternating charge� large diameter and deep penetration then pull the tubing with the packer in the well so that the lower end of the tubing was at the level of the roof of clay interbed, carry out the planting of the packer in the well, produce low-permeability fracturing the formation with the fracturing of the injection of hydraulic fracturing fluid along the tubing string through the perforated intervals of clay interbed, then pumped into the cracks trim cross-linked gel hydrocarbon based in the amount of 3-5 m3a flow rate of 10 m3/min, and as the proppant used proppant mixture, and then produce the fixing cracks in portions injection of hydraulic fracturing fluids and proppants mixture, since the concentration proppants mixture of 400 kg/m3with a step increase in its concentration of 200 kg/m3in hydraulic fracturing fluid in each serving and a flow rate of 5 m3/min, and proppanow the mixture is prepared at the wellhead in the following ratio, wt.%: the proppant 12/40 mesh. - 30%; the proppant 18/20 mesh. - 30%; silica flour - 40% on completion of hydraulic fracturing in low-permeability layer removes the temporary isolation of a perforated interval the low permeability of the reservoir and carry out the perforation of the low permeability of the reservoir formation fluid communication between the wellbore and hydraulic fracture.
FIELD: oil and gas industry.
SUBSTANCE: in the method of well operation stimulation including test injection of breakdown fluid and package of breakdown fluid with proppant, correction of the breakdown project and performance of fracturing in low-permeable reservoirs having absolute permeability less than 1mD, hydraulic fracturing is made with injection of flush fluid on the basis of 1.0-3.0 m3 per 1 t of proppant using proppant fractions, which include only fine fraction with size less than 30/60 mesh with final concentration of proppant less than 300 kg/m3; at injection of the fluid flow rate of 3.5 m3/min and more and concentration of gel formation is set less than 2 kg/m3, with final underflush of the mixture in volume of 0.1-0.5 m3.
EFFECT: simulation of the well opening the low-permeable formation.
SUBSTANCE: method involves drilling of a horizontal well, lowering to a vertical part of the well of a casing string and its cementing, lowering of a pipe string with a packer to a well, seating of the packer, formation of fractures of formation hydraulic fracturing (FHF) in the horizontal well shaft by pumping via the pipe string of fracturing fluid, and fixation of fractures by pumping of carrier fluid with proppant. The horizontal shaft is drilled perpendicular to direction of minimum main stress. FHF is performed by pumping of fracturing fluid with flow rate of 2-3 m3/min with formation of a longitudinal fracture in the formation relative to the open horizontal part of the well; crosslinked gel is used as fracturing fluid; then, fixation of a longitudinal fracture is performed by pumping via the pipe string of proppant of large fraction with carrier fluid - crosslinked gel. Then, FHF is performed by pumping of fracturing fluid with flow rate of 7-9 m3/min; line gel is used as fracturing fluid; after that, fixation of branched FHF fractures is performed by pumping of proppant of small fraction with carrier fluid - line gel.
EFFECT: improving FHF efficiency and reliability.
FIELD: oil and gas industry.
SUBSTANCE: method comprises test forcing of fracturing fluid and pile of fracturing fluid with proppant, correcting the fracturing project and performing of the main fracturing process. In highly permeable reservoirs with absolute permeability not less than 100 mD the main fracturing process is carried out with usage of proppant fractions, which include initial fraction with mesh size from 30/40 up to 20/40 and the main coarse fraction with mesh size of 12/18 and more in the volume not less than 70% of the total proppant quantity with final proppant concentration not less than 750 kg/m3. While injecting fraction with mesh size of 12/18 and more through perforated openings fluid consumption is set so that it does not exceed 3 m3/min and wellhead pressure is maintained at the level less than 35 MPa.
EFFECT: improving the efficiency of hydraulic fracturing for highly permeable strata.
SUBSTANCE: invention relates to a propping agent and use thereof in hydraulic fracturing for oil and gas extraction. The ultralight propping agent is prepared from a mixture of raw materials comprising porcelain clay, pottery clay and kaolin and/or siliceous clay, in the following content, wt %: porcelain clay 5-85, kaolin and/or siliceous clay5-85, pottery clay 5-30. The ultralight propping agent with apparent specific gravity of 2.10 g/cm3 to 2.55 g/cm3 and volume density of 1.30 g/cm3 to 1.50 g/cm3 is prepared from a mixture of natural clays comprising porcelain clay, pottery clay and at least kaolin or siliceous clay, where alumina content is 5.5-35%. In the method of preparing said filler, high strength of the propping agent is achieved by controlling firing time in the range of 75-90 minutes and firing temperature of 1150°C to 1380°C. Sintered spherical granules prepared from a mixture of raw materials comprising porcelain clay, pottery clay and at least kaolin or siliceous clay, having a substantially circular or spherical shape, are characterised by a Krumbein coefficient of at least 0.8 with alumina content of 5.5-35%. The hydraulic fracturing method includes pumping into an underground formation a hydraulic fluid with flow rate and pressure sufficient for opening a fracture in the formation, and the fluid containing said filler is pumped into the fracture.
EFFECT: high strength of the propping agent and conductivity thereof.
29 cl, 13 tbl, 5 ex
SUBSTANCE: method involves drilling of a horizontal well shaft, lowering and fixation of a shank with filters, lowering of a packer and its seating, formation of cracks in each of the zones, which correspond to intervals of parts of the horizontal shaft with insulation of the rest of its parts. With that, the lower end of a pipe string is located 1 m closer to the mouth from the distant formation interval; a string of flexible pipes is lowered into the above pipe string and it is equipped from below with an abrasive jet perforator; space between the pipe string and the string of flexible pipes is sealed at the well mouth. Groups of slit perforation holes are made with length of 20-30 cm and width of 15 mm with a phasing angle of 60° in every 1.5 m of the oil-saturated formation interval in the shank; reverse flushing is performed together with simultaneous movement of the string of flexible pipes from the mouth to the face throughout the length of the oil-saturated formation interval; the string of flexible pipes with a jet nozzle is removed, and hydraulic formation fracturing is performed with further fixation of a fracture by light-weight resin-coated propping agent with fraction size of 20/40 mesh in concentration of 1400 kg/m3 and its filling to the horizontal well shaft opposite the oil-saturated formation interval; the packer is removed; the pipe string is moved in the direction from the face to the mouth to the next oil-saturated formation interval; after that, the above operations are repeated starting from seating of the packer and ending with the packer removal in the rest oil-saturated formation intervals developed by the horizontal well shaft.
EFFECT: improving reliability of hydraulic formation fracturing and efficiency of fracture fixing.
SUBSTANCE: method comprises the formation exposing by vertical well, tripping in the well on the pipe string of the water jet tool with even amount of injection nozzles and its placement in the preset interval of the formation, injection of driving fluid through injection nozzles of the water jet tool for caving in the formation, subsequent formation fracturing from caverns by the spray stagnation pressure in caverns. Meanwhile the water jet tool with a series of injection nozzles, located along the tool with the interval between nozzles in a line no more than two diameters of the casing is used. The water jet tool is rotated to the preset angle to change the direction of progressing of each subsequent fracture. The fractures are formed at driving fluid injection pressure in the casing below the side rock pressure. Before tripping of pipe string into the well in the bottom end of the water jet tool the rotating device and mechanical packer are installed. To compensate leakages and the wedging of fractures during the process of hydraulic formation fracturing an acid is added in volume equal to 20% of the volume of the driving fluid, the driving fluid is injected into the pipe string through the water jet tool into a cavern until fracturing, then into the annular space of the well an acid is injected to compensate the leakages and fracture wedging. The pressure of acid injection into annular space of the well amounts 85% from the pressure created in the pipe string during progressing of fracture, upon termination of progressing fracture and the wedging of fracture in the same direction raise a pipe string on 1 m, turn a pipe string on an angle applicable to a direction of forming of following fracture, and lowered, then the process operations are repeated.
EFFECT: improvement of accuracy of orientation of fractures, performance and reliability of fracturing of carbonate reservoirs.
SUBSTANCE: method comprises the drilling of a horizontal well bore in oil saturated part of the productive formation of the well, tripping of the pipe string into the well, the forming of perforations and fractures using the a hydrofracturing of formation in the hole of horizontal well, successively, starting from the end of far from the vertical borehole axis. During the next hydrofracturing the section, through which hydrofracturing is performed, is insulated from another part of the string with a packer. During drilling of the horizontal well bore the permeability and porosity of rocks are determined and the intervals of the productive formation with low permeability and porosity of rocks are identified, and on completing of drilling the rock hydrofracturing pressure is determined in each interval of the horizontal borehole. Then the volumes of fracturing fluid and acid for each interval of the oil saturated part of the formation with low permeability and porosity are determined, then the pipe string is moved to the interval of the productive formation nearest to the borehole bottom, with low permeability and porosity, the mechanical packer is seated, from hole mouth using the pumping unit the gelled fracturing fluid is injected into the pipe string through nozzles of the water jet tool and reshape perforations, then, not stopping injection gelled of fracturing fluid on a pipe string, construct fracture pressure applicable to the given interval of the oil saturated part of the productive formation. After 30% drop of pressure of injection of gelled fracturing fluid in the pipe string the hydrofracturing fractures are formed, for this purpose into the annular space of the well an acid is injected at the variable flow rate ensuring maintaining of pressure of injection of gelled fracturing fluid in the pipe string 10% less than the fracture pressure for the given interval of the oil saturated part of the productive formation. The packer releasing is performed and the pipe string is removed from bottomhole to the mouth into the following interval of the oil saturated part of the formation with low permeability and porosity of rocks for forming perforations and conducting of a hydrofracturing of the formation with forming and progressing of fractures.
EFFECT: shortening time for formation hydrofracturing, improvement of performance and reliability of formation hydrofracturing.
FIELD: oil-and-gas industry.
SUBSTANCE: invention relates to subsurface formations processing in the production of hydrocarbons. Method of processing a subsurface formation crossed by a hole comprises: preparation of a processing fluid containing a viscoelastic surfactant with at least one degradable link, a hydrolysable material and a pH adjusting material. Note here that the latter has a pH value equal to or larger than 9 and contains a strongly alkaline substance and an oxidiser. The said processing fluid is injected in the subsurface formation. The invention is developed in dependent claims.
EFFECT: higher efficiency of the proppant transportation and decomposition at low temperatures.
21 cl, 1 tbl, 14 dwg
FIELD: oil-and-gas industry.
SUBSTANCE: proposed method comprises test injection of frac fluid and bundle of frac fluids with proppant, correction of frac project and execution of the main frac process. Well is equipped with extra string and tube space is cemented. At hydrofrac, components are injected via said extra string at communicated perforation interval and well top space at pressure lower than permissible for extra string and at low frac fluid flow rate.
EFFECT: intensified production at worn-out string.
SUBSTANCE: as per method of hydraulic fracturing of underground medium, many sliding couplings are placed in a well passing into underground media; sliding couplings are placed in mutually spaced places along the well and provided with a possibility of control after arrangement in the well in any specified sequence; many signal devices are moved along a control line arranged in the well; each of the signal devices opens at least one of the multiple sliding couplings and performs hydraulic fracturing of underground media in any specified sequence in mutually spaced places along the well passing into underground media; sliding couplings are used at hydraulic fracturing and left in the well at performance of hydraulic fracturing.
EFFECT: optimisation of stresses created due to hydraulic fracturing from mutually spaced places along the well shaft.
16 cl, 5 dwg
SUBSTANCE: invention relates to manufacture of molded ceramic materials for use as propping agent in production of liquid and gaseous fluids from bored wells. Method comprises briquetting and heat treatment of aluminosilicates kaolin at 1150-1250оС. Resulting mix is ground to average grain size 3-5 μm and loaded into granulator. Before granulation, 1.2-3.0% mineralizer and 5-10% plasticizer are added. Mix is moistened with dozed amount of organic binder and stirred to form granules. At the end of granulation, fired ground material for powdering granules is added in amount 1.2-3.0%. Granules are dried and screened to isolate desired fraction, which is subjected to final firing at 1370-1450оС for 30-60 min and then re-screened into commercial fractions.
EFFECT: enabled manufacture of granules having low loose density and high strength allowing their use at depths up to 14000 feet (4200 m).
3 cl, 1 dwg, 1 tbl, 3 ex
FIELD: oil and gas production.
SUBSTANCE: proppant used in oil production involving hydraulic fracturing of formation contains ceramic granules coated with novolac resins supplemented by catalytic aqueous urotropin solution in organosilicon emulsion. Proppant preparation method comprises preparing granules and coating them. The latter operation is carried out as follows. Granules are heated to 150-160°C, dry novolac resin and catalytic urotropin solution are added at stirring in two equal portions with respect to the weight of resin and urotropin. When dropping temperature achieves 95-100°C, organosilicon emulsion is added provide following proportions of ingredients: 5.0-8.0% of novolac resin, 1.5-3.0% of 33% urotropin solution, 0.1-0.3% of organosilicon emulsion, and ceramic granules - the rest. Granules are finally cooled. Organosilicon emulsion is prepared at emulsion-to-water ratio 1:10.
EFFECT: increased strength of ceramic proppant and improved its quality due to resin coating applied with separating emulsion.
2 cl, 1 dwg, 1 tbl, 2 ex
FIELD: oil and gas production.
SUBSTANCE: fluid contains, wt %: industrial-grade powdered lignosulfonates 26.4-31.7, potassium chloride 4.9-5.9, aluminum sulfate 1.2-1.50, borax 0.4-0.5, formation water 40.3-44.7, and sweet water in proportion to formation water as 1:(1.98-1.99).
EFFECT: improved process parameters due to improved structurally mechanical properties of fluid, raised viscosity thereof, high sand-retention ability, and possibility of controlling lifetime without loss in high technological characteristics.
1 tbl, 2 ex
FIELD: oil and gas production.
SUBSTANCE: in a method of preparing propping agent including grinding, hydration, molding, drying, and calcinations of raw material, the latter is natural bentonite clay containing more than 90% montmorillonite, molding of spherical granules of propping agent 200 to 400 μm and 420 to 850 μm in size involves spray drying technique and molding of granules more than 850 μm in size is accomplished using beading process, and calcinations is carried out at 600-650°C. Method is applicable for use in intensification of oil and gas inflow from producing beds.
EFFECT: reduced expenses of hydraulic fracturing of formation.
FIELD: oil and gas production.
SUBSTANCE: invention relates to production of proppants, i.e. splitting granules, used in oil and gas production via breakdown way. Proppant of invention is obtained from caked two-component aluminosilicate fees in the form of granules with density 2.2-3.0 g/cm3 and 0.2-2.5 mm in size consisting of nucleus and shell, wherein one of components of aluminosilicate feed, which forms granule nucleus is a low-alumina substance containing less than 30% of alumina: coal combustion ashes, preliminarily fired kaolin, nepheline, nepheline syenite, feldspar, shale, or alumina production slime waste, and other component of aluminosilicate feed, which forms granule shell, is a high-alumina substance containing above 70% alumina: alumina dust of electrofilters of aluminum hydroxide calcination furnaces, industrial alumina, preliminarily fired bauxite, and exhausted catalysts based on active alumina form. Feed contains 50.0-95.0% low-alumina substance and 5.0-50.0% high-alumina component. In a method for production of proppant from two-component feed including (i) granulation upon addition of binding component in mixer-granulator provided with plate cup rotating at constant speed and rotor-type stirrer whose rotation speed is varied in dependence of granulation stage, (ii) drying, (iii) sizing of fried granules, (iv) firing of granules in rotary furnace, and (v) sizing of fired granules to form commercial fractions, when obtaining above-indicated proppant, low-alumina substance is used in the first granulation stage and, after granules 0.15-2.0 mm in size are formed, second granulation stage comprises addition of high-alumina substance into granulator followed by further granulation until granules 0.2-2.5 mm in size are obtained. Preliminary firing of low-alumina substance (as defined above) is carried out at 700-1200°C and the same of high-alumina substance (as defined above) at 700-1400°C. Firing of dried granules id effected at 1100-1600°C. Binding substance is used in the form of aqueous suspension of an organic binder (carboxymethylcellulose, methylcellulose, low-grade lignosulfates) of aqueous suspension of clay, wherein concentration of suspended binder is 1.0-10.0%. Aqueous suspension is added during granulation process in amounts 10.0 to 40.0% of the weight of initial feed.
EFFECT: enabled production of proppants from accessible raw materials (production wastes) without complication of existent technology.
9 cl, 1 tbl, 14 ex
FIELD: oil production from drill-holes, particularly to stimulate productive beds by bed drainage and formation fluid filtering channel forming.
SUBSTANCE: method involves forming at least one opened horizontal well bore or one opened horizontal well bore with at least one opened side branch bore extending along the strike in productive area thereof; filling the bore with hydrophobic granular material, wherein bore and branch bore filling is performed in portions along with compacting each portion of granular material up to material subsidence and existent natural bed cracks opening under the action of material compaction; installing and fixing filtering unit in well bore. Device comprises sectional or continuous pipe string, conical flared body fixedly secured to pipe string. Arranged in the body is system including pusher with central through channel and with cone. The pusher is hung inside the body and connected to cylindrical spring so that the pusher may be axially displaced and perform self-oscillations. Flared body and pusher cone are axially joined and form valve couple. Freely sliding impact bush is located over pusher anvil.
EFFECT: increased hydrocarbon material output and increased oil and gas recovery factors.
4 cl, 1 ex, 3 dwg
FIELD: mining, particularly to weaken coal bed and to increase recovery of desorbed methane.
SUBSTANCE: method involves drilling well from well surface; casing the well; exposing coal bed; injecting working liquid in the coal bed, wherein the working liquid has pressure enough to perform hydraulic fracturing of the bed and flow rate providing elongated crack forming. Salt solution, gel with propane or gel decomposition substance are used as the working liquid. Propane content in gel is gradually increased from 50-100 kg/m3 to 500-600 kg/m3 as cracks are formed and fixed. The salt is potassium chloride or propant having particle diameters of 20-40 meshes. Coal bed exposing is performed by cutting casing pipe and cement ring in central bed zone within interval of 100 mm so that the ready hole has height of 50-100 mm. The coal bed may be also opened by coal bed drilling below casing pipe for depth of 50-100 mm.
EFFECT: increased formation weakening and increased methane recovery.
3 cl, 2 ex
FIELD: technology for increasing recovery of hydrocarbons from foliate geological formations, which contain absorbed condensed gaseous hydrocarbons, by processing such geological formations with dehydrating compositions, containing surfactants, which cause dampening of geological formation with oil or leave aforementioned formations dampened with oil.
SUBSTANCE: methods may be used for excitation of influx of fluid substance from geological formation into well, or hydro-acid fracture, or hydraulic fracture, during maintenance or major repairs and when increasing influx from natural cracks or from geological formations never subjected to influx stimulation.
EFFECT: increased water removal efficiency, minimization of migration of low dispersion particles, increased extraction of hydrocarbons from underground formations, containing absorbed and compressed gaseous hydrocarbons.
3 cl, 4 ex, 6 tbl
FIELD: measuring technique.
SUBSTANCE: method comprises allowing the main liquid to flow through the Coriolis flow meter, measuring the density of the main liquid, and transmitting the signal containing measured value of the signal to the control system, adding the filler to the main liquid, allowing the mixture to flow through the Coriolis flow meter, and transmitting the measured value of density to the control system.
EFFECT: enhanced accuracy.
19 cl, 5 dwg
FIELD: manufacture of granulated materials used as wedging filler and gravel filter for control of sand flow.
SUBSTANCE: proposed granulated material has particles coated with two or more layers of hardenable coat; coated particles include granulated substrate and at least one layer of first curable resin practically embracing the substrate and at least one layer of second curable resin practically surrounding at least one layer of first curable resin; amount of curing agent in layer of first curable resin and in layer of second curable resin is lesser than that at which resin is practically cured.
EFFECT: increased compressive strength; increased elasticity; high strength at curing; forming strong blocks of wedging filler at pumping granulated material into well.
86 cl, 1 dwg, 12 tbl