Method of insulating formation water inflow

FIELD: oil and gas production.

SUBSTANCE: invention relates to insulating formation water inflow in gas and gas condensate wells with the aid of coltubing techniques. In particular, flexible conduit is descended through the tube space of well operated under pressure to the bottom with the aid of coltubing installation. Latches on tube and annulus spaces are opened. Well hole is filled through flexible conduit with gas condensate. Grouting mortar is prepared in preparation block by mixing cement mortar with setting retardant and mortar flowability enhancer in a calculated amount needed to prevent formation water inflow. Further, flushing fluid, e.g. methanol, is pumped through flexible conduit in amount constituting 0.3-0.6 volume of flexible conduit. Annulus space is closed and grouting mortar is pumped through flexible conduit in amount required to fill well hole in interval of water-inflow part of formation. When grouting mortar in hole rises to specified height, tube space is closed and grouting mortar contained in flexible conduit is forced into water-inflow part of formation by in series pumped flushing fluid and displacing solution: for example first methanol in amount 1.0-1.3 volumes of flexible conduit and then gas condensate in required amount, which however does not exceed internal volume of flexible conduit, until grouting mortar begins being pumped in amount of 0.3-0.5 volumes of flexible conduit. Then tube and annulus spaces of well are opened and gas condensate begins being simultaneously pumped into tube and annulus spaces in order to prevent rise of grouting mortar therein above interval of the water-inflow part of formation. Thereafter, bottom of flexible conduit is raised by 1 m above indicated interval and excess of grouting mortar is cut and washed away with gas condensate passed through flexible conduit into tube space, where excess grouting mortar remains in fluid state. After cement setting expectation time, flexible conduit is descended to the top of cement column and tests the latter for strength applying 4.0-5.0 kN loading by means of injector of coltubing installation through flexible conduit. Finally, cement bridging is subjected to hydraulic pressurization and flexible conduit is removed from well.

EFFECT: enabled formation water inflow insulation without killing of well and restricted pollution of water-inflow part of formation.

3 cl, 1 dwg

 

The invention relates to the oil and gas industry, namely to isolate the flow of formation waters in the gas and gas condensate wells using coiled tubing technology.

There is a method of isolating the flow of formation waters, including injection vodoprivredu part of the layer of cement slurry under pressure and patience well at the time of setting of cement slurry [Reference book on current and capital repair of wells / Ademero, Casareto, Fdimike and others - M.: Nedra, 1979, - S-241].

The disadvantage of this method is the inability to isolate the flow of formation waters in the gas and gas condensate wells without killing them, and the inevitable pollution Gazpromavia of the reservoir due to the ingress of backfill material when carrying out waterproofing works.

There is a method of isolating the flow of formation waters, including injection vodoprivredu part of the layer of cement slurry under pressure and patience well at the time of setting of cement slurry [RF Patent №2127807 E 21 In 43/32].

The disadvantage of this method is the inability to isolate the flow of formation waters in the gas and gas condensate wells without killing.

The challenge when creating the invention is to provide opportunities isolate the flow of formation without plugging wells

Achievable technical result, which is obtained by the invention, is the ability to isolate the flow of formation waters without killing the well by limiting the extent of contamination Gazpromavia of the reservoir and providing quality plugging vodoprivreda part of the layer.

The task and the technical result is achieved by the fact that in the known method of isolating the flow of formation waters, including injection vodoprivredu part of the layer of cement slurry under pressure and patience well at the time of setting of cement slurry in contrast to the known into the tube space of the well under pressure, down to the bottom using coiled tubing installation flexible pipe, open the valve on the pipe and the annular space, the wellbore is filled through her gas condensate, produced in the block of preparation of cement slurry by mixing cement with a setting retarder and a reagent that increases the fluidity of the solution, to the extent necessary to eliminate inflow produced water, estimated by known methods depending on the geological formation on the results of geophysical and hydrodynamic studies wells, pumped through a flexible tube buffer fluid, in the example methanol, in the amount of 0.3 to 0.6 volume of the flexible tube, close the annulus and pumped through a flexible pipe grouting mortar in required to fill the well bore in the interval vodoprivreda part of the layer number, after lifting cement slurry into the well at a predetermined height closed tubular space and begin to push cement slurry, located in the flexible tube, vodoprivredu part of the reservoir sequentially injected buffer liquid and squeezing solution, for example, the first injection of methanol in a volume of 1.0-1.3 volume of the flexible pipe, and then gas condensate, to the extent necessary, but not more than the internal volume of the flexible pipe, to after pumping through a flexible pipe cement slurry in the amount of 0.3 to 0.5 volumes of flexible pipe, then open the pipe and the annulus of the well and simultaneously injected into the flexible tube begin to pump gas condensate in the pipe and annulus to prevent lifting of cement slurry in the pipe and annulus above interval vodoprivreda of the reservoir, then lifting Shoe with flexible pipes 1 m above interval vodoprivreda of the reservoir, produce section and leaching of excess cement slurry gas condensate supplied through a flexible pipe, pipe spaces is about and leaving them there in the liquid state, after RFQ lower flexible pipe to the head cement and glass and feel his strength, putting a load of coiled tubing injector installation through a flexible pipe force 4,0-5,0 kN, then produce hydraulic pressure testing of a cement bridge, after which a flexible pipe is extracted from the well.

The drawing shows the circuit implementation of this method.

The method is implemented as follows.

Into the well under pressure, down through the coiled tubing installation 1 through the guide groove 2, the injector 3, the block preventer 4, x-Mas tree valves 5, Elevator column 6, is placed inside the casing 7 of the flexible pipe 8 to a depth of 1 m above the bottom 9. Next, open pipe 10 and annulus 11 space well (respectively between the flexible pipe 8 and the Elevator column 6; between the Elevator column 6 and the production column 7) and the wellbore through a flexible pipe 8 is filled stable gas condensate 12, excluding the presence of water and aqueous solutions of salts (l2NaCl), in the estimated amount. In winter pumped gas condensate is heated to positive temperatures. In the absence of absorption of condensate reservoir spend circulation wells condensate to complete degassing of the condensate, but not less than one cycle. In the absence of circulation after injection of RA is an even amount of condensate pumping stop and start to execute the next process operation.

Filling the wellbore condensate prevents direct contact cement slurry with Gazpromavia part of the reservoir 13, reduces the degree of pollution of bottom-hole formation zone and slows the setting time of cement slurry, pumped through a small area of passage of the flexible tube 8.

Then at the wellhead prepare the desired composition of cement water-based density 1700 kg/m3in need for isolation vodoprivreda of the reservoir 14 volume, estimated by known methods depending on the geological formation on the results of geophysical and hydrodynamic research well. The necessity of pumping the cement slurry through the small flow section of the flexible pipe 8 in order to prevent premature hardening and blockage of its section presents the composition of the cement slurry certain requirements. First, pumped through a flexible tube 8 cement slurry must be greater than when pumping it through the Elevator column of larger diameter, the binding time. Secondly, he must have high fluidity. Therefore, in the prepared cement mortar add the retarder solution and the reagent, which increases its fluidity. The resulting solution was thoroughly stirred to proceneonate mass with parameters: density - 1600-1650 kg/m3; viscosity of 40-50 C. the binding Time of the obtained cement slurry of experience repairing wells in Yamburg field reaches 10 hours.

After preparation of cement slurry open the valve on the pipe 10 and annulus 11 spaces and the well pumped through a flexible pipe 8 at the beginning of the buffer fluid 15, such as methanol, in the amount of 0.3 to 0.6 volume of the flexible tube 8, and then, after closing the annulus 11, - cement slurry 16 to fill the wellbore volume, in the range vodoprivreda of the reservoir 14.

Stable gas condensate 12 located on the bottom 9, under the influence injected into the well buffer fluid 15 and cement slurry 16 is extruded into pipe 10 and annulus 11 space well, and some in getprofiles 13 and vodoprivredu 14 of the reservoir.

After lifting cement slurry 16 in the annular space between the flexible pipe 8 and the production column 7 at a predetermined height, the overlapping interval vodoprivreda of the reservoir 14, the closed tubular space 10 and begin to push cement slurry 16 in vodoprivredu part of the reservoir 14 sequentially injected buffer fluid 15 and squeezing solution 17, for example, the first injection of methanol in a volume of 1.0-1.3 volume of the flexible tube 8, and ZAT is gas condensate, to the extent necessary, but not more than the internal volume of the flexible tube 8.

After being pumped through a flexible tube 8 cement slurry 16 in the amount equal to 0.3 to 0.5 volumes of flexible pipes 8 open pipe 10 and annulus 11 space well and begin to upload and squeezing solution 17 (stable gas condensate) in the tube 10 and annulus 11 space (at low speed pump installation) to prevent lifting cement slurry 16 in these spaces above interval vodoprivreda of the reservoir 14.

Injection of methanol as a buffer fluid 15, slows the setting time of cement slurry 16 and increases its fluidity, and the injection of gas condensate, as the squeezing solution 17 in the tube 10 and annulus 11 space enables the creation of hydrostatic pressure in the wellbore and prevents lifting of head cement and glass 18 formed by the injection of cement slurry 16 on hole 9, above the desired height needed to isolate the flow of formation waters in the interval vodoprivreda of the reservoir 14), slows the setting time of cement slurry.

Next, lift the Shoe flexible pipe 8 at 1 m above the “estimated” head cement and glass 18 formed by the injection of cement slurry 16 on hole 9, the produce section of excess tamponing the solution 16 of stable gas condensate, supplied through a flexible pipe 8, to the desired height of head cement and glass 18 (upper level vodoprivreda part of the layer 14) and the leaching of excess cement slurry 16 in tube space 10. Leave the hole on the waiting period of hardening of cement (RFQ) for 48 hours.

After RFQ lower flexible pipe 8 to the head cement and glass 18 and determine the actual location of his head. If necessary, cement glass 18 increasing pouring cement slurry 16 without pressure. After that checks the cement and glass 18 to strength, putting by means of the injector 3 load cement glass 18 through a flexible pipe 8 by a force not exceeding 4,0-5,0 kN. In case of loss of circulation produce full rise of the flexible tube 8 to the surface. Excess cement slurry 16 remain in the tube space 10 in the liquid state and are removed from the well during stimulation and testing of wells on the torch.

The setting of cement slurry 16 in the tube space of 10 does not occur due to the mixing of the excess cement slurry 16 with methanol and stable gas condensate. Then produce a hydraulic pressure test zemelnogo cups 18 on the maximum pressure expected on the mouth, but not more than the pressure of the crimp production casing 7. At the Yamburg field max the maximum expected pressure at the mouth at the present time is 4.0 to 6.0 MPa.

Upon completion of testing cement and glass 18 on the strength and integrity of the wells extract a flexible pipe 8.

An example implementation of the method.

You must also isolate the inflow of formation water in the well with low permeability and porosity with depth H=1200 m, the thickness of obwodnica of the reservoir h=20 m, the thickness of its productive part 60 m, the porosity of the stratum m=0,17. Here is only possible method of repair and insulation works by using coiled tubing equipment without killing the well.

Plugging obwodnica part of the layer have a depth of R=3,0 m, Then the volume of the plugging solution will be:

V=π R2hm=96,1 mC.

Define bottom-hole pressure in the injection of cement slurry PC·CEM. Because the rate of injection of the cement slurry is small, we neglect the pressure losses by friction in the flexible tube.

PC CEM=Pthe C+10-5·ρ

W
·N

where Rthe C- pressure on the mouth while pumping cement slurry, 6,0 MPa;

ρW- density and squeezing fluid (stable gas condensate), equal to 700 kg/m3.

PC CEM=14.4 MPa.

Define bottom-hole pressure during pumping and squeezing what about the solution (stable gas condensate) in the pipe and the annulus R C·cond:

PC cond=Pu K+10-5·ρ

W
·N

where Ru K- pressure at the mouth during pumping and squeezing solution (stable gas condensate)of 6.5 MPa.

PC cond=of 14.8 MPa.

When implementing the described method is plugging mainly vodoprivreda part of the layer without appreciable reduction of the filtration parameters Gazpromavia part because the above areas plugging creates a gas-liquid elastic barrier by produce it stable gas condensate, which will allow relatively little effort to quickly learn the borehole after completion of repair and insulation works.

PC cond>RC CEM.

The proposed method of isolating the flow of formation waters in the wells allows repair and insulation works without killing the well, reducing the degree of pollution of bottom-hole formation zone, to reduce the duration of repair work 5-6 times, reduce costs, and the cost of repairs well in 3-4 times.

1. The way to isolate the flow of formation waters, including injection vodoprivredu part of the layer of cement slurry under pressure and promotional is Riku well at the time of setting of cement slurry, characterized in that the tube space of the well under pressure, down to the bottom using coiled tubing installation flexible pipe, open the valve on the pipe and the annular space, the wellbore is filled through her gas condensate, produced in the block of preparation of cement slurry by mixing cement with a setting retarder and a reagent that increases the fluidity of the solution, to the extent necessary to eliminate the inflow of formation water, which is determined by calculation, pumped through a flexible tube buffer liquid, in the amount of 0.3 to 0.6 volume of the flexible tube, close the annulus and pumped through a flexible pipe grouting mortar in required to fill the wellbore interval vodoprivreda part of the layer number, after lifting cement slurry into the well at a predetermined height closed tubular space and begin to push cement slurry, located in the flexible tube, vodoprivredu part of the reservoir sequentially injected buffer liquid in a volume of 1.0-1.3 volume of the flexible tube and squeezing the solution, to the extent necessary, but not more than the internal volume of the flexible tube until the pump through a flexible pipe cement slurry in the amount of 0.3 to 0.5 volumes of flexible pipe, then open the tube and Strub the second space of the well and simultaneously with the injection flexible pipe begin to upload and squeezing the solution in the tube and the annulus to prevent lifting of cement slurry in the pipe and annulus above interval vodoprivreda of the reservoir, then lifting Shoe with flexible pipes 1 m above interval vodoprivreda of the reservoir, produce section and leaching of excess cement slurry gas condensate supplied through a flexible tube into the tube space and leaving them there in the liquid state, after waiting hardening of cement down a flexible tube to the head cement and glass and feel his strength, putting a load of coiled tubing injector installation through a flexible pipe force 4,0-5,0 kN, then produce hydraulic pressure testing of a cement bridge, after which a flexible pipe is extracted from the well.

2. The method according to claim 1, characterized in that as the buffer fluid use methanol.

3. The method according to claim 1, characterized in that as the squeezing solution using gas condensate.



 

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