Method for isolating penetrable beds in a well
FIELD: oil and gas chambers construction.
SUBSTANCE: method includes pumping of portion of water-absorbing acryl polymer, exposure of it in a well, pumping of second portion of same polymer, tempered on fresh water with concentration 1-20%, buffer of fresh water dries up, and before and after pumping of second portion of water-absorbing polymer, tempered on hydrocarbon liquid with concentration 10-20%, buffer of hydrocarbon liquid is pumped in, besides, said 2-portion systems are pumped into well multiple times.
EFFECT: higher efficiency.
1 ex
The invention relates to the construction of oil and gas wells, in particular to the isolation of permeable formations, as in drilling and overhaul.
There is a method of isolation of the permeable formation comprising pumping into the well plugging material based on acrylic polymers and their derivatives [1]. These water-soluble polymers used in water compositions in combination with electrolytes, forming or precipitation (gels)or viscoelastic seal weight, stable in the environment of saline and fresh water.
However, the method has drawbacks. Cross-linked polymer in the process of leveling in the insulated layer passes through the pores streams and takes shape in the cross section, which further does not cause resistance to the interaction of water sources nearby reservoirs. In addition, this method consistently pumped electrolyte, the polymer was then and again the electrolyte. When uneven porosity and permeability of rocks these components are not always fully involved in the reaction. Therefore, the output of the insulation material are low. Hence low efficiency and insulation works.
The closest technical solution chosen by the authors for the prototype is the way to isolate the permeable formation in a well comprising pumping portion swollen acrylic polymer AK-639 extract it in the well and the injection of the second portion of the same polymer.
This method has the following disadvantages.
When isolation of permeable layers of high-power and high pickup swollen polymer even when the concentration of the polymer of 20% goes into the depth of the reservoir and does not isolate the major channels in fractured and porous reservoirs
The objective of the invention is improving the efficiency and insulation works by providing fill fractured rocks, large canals in them grouting composition, limiting deep penetration swollen polymer in permeable reservoir rock.
The problem is solved due to the fact that the method of isolation of the permeable formation in a well comprising pumping portion swollen acrylic polymer AK-639, extract it in the well and the injection of the second portion of the same polymer, before and after injection of the first portion of the swollen polymer shut on fresh water with a concentration of 1-20%, is pumped buffer of fresh water, and before and after injection of the second portion swollen polymer shut on a hydrocarbon liquid with a concentration of 10-20%, they fill the buffer from the hydrocarbon liquid, additionally, the well pumped mentioned 2 portions of the system repeatedly.
Essentially with this method the problem is solved due to the following additional mechanism for the formation.
Swollen polymer satoren the first hydrocarbon fluid, inert. Therefore, it penetrates into large cracks, simultaneously plugging the inlet of small channels.
In large channels swollen polymer at some distance from the wells is mixed with fresh water. The polymer swells and covers a large channel, because it uses all its ability to swell in 100%. While the injection of swollen polymer shut on fresh water, he at the approach to the insulated interval loses up to 50% of its capacity to swell.
Example of commercial application of the method:
For carrying out insulation work in a well drained column tubing (tubing) to the roof of the insulated layer.
The layer presents srednetsenovoj breed.
For isolation of the reservoir in the casing at the closed annulus is pumped buffer of fresh water and is determined by the injectivity of the well.
Then closes the first portion of the swollen polymer in fresh water and pumped into the well. After that pumped buffer of fresh water.
The second portion of the swollen polymer is prepared in the following sequence: injection buffer of the hydrocarbon fluid, the swollen polymer, shut hydrocarbon fluid, a buffer from the hydrocarbon liquid.
In this sequence in the well for Aquatica several 2 portions of insulation systems if you have to isolate the reservoir, presents krupnosemyannye rocks.
In addition, when the insulation layers with high permeability, for example, more than 40 m3/h at a pressure at the wellhead of the order of 60-80 kg/cm2the concentration of swollen polymer in the oil increases due to the reduction of oil viscosity. For this purpose the oil is pre-injected surfactants, such as the brand "Neonol" 6 m3oil 9 l PAVA.
The proposed method differs from the known, which limited the effectiveness of the application in insulation works in permeable rocks, represented by large cracks or channels.
The advantage of the proposed method over the known is to ensure wide use of it in almost all ranges of permeabilities of rocks, as in the isolation of fractured carbonate rocks, and terrigenous. The method is equally applicable in cased and uncased wells.
Known technologically-not suitable for use with the elimination of water flows between reservoirs with different formation pressure, because the grouting mixture razbavlyali will be replaced, whereas the proposed method eliminates this process. A portion of the swollen polymer shut on hydrocarbon liquids when in contact with water will intensively to respond is due to the rapid structure formation to create a jumper with high bridging properties.
1. The method of isolation of the permeable formation in a well comprising pumping portion swollen acrylic polymer AK-639, extract it in the well and the injection of the second portion of the same polymer, characterized in that before and after injection of the first portion of the swollen polymer shut on fresh water with a concentration of 1-20% of the injected buffer of fresh water, and before and after injection of the second portion swollen polymer shut on a hydrocarbon liquid with a concentration of 10-20%, they fill the buffer from the hydrocarbon liquid.
2. The method of isolation of permeable formations in a borehole according to claim 1, characterized in that the well pump 2-batch system repeatedly.
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
FIELD: oil and gas production.
SUBSTANCE: invention relates to grouting mortars used for cementing casing pipes of gas, gas-condensate, and oil wells complicated by presence of formations with low hydraulic rupture pressure as well as presence of permafrost rocks. Light-weight grouting mortar contains 47.0-60.0% special-type cement, 6.6-11.8% clinoptilite as light-weight additive, and water. As a result, casing-pipe annulus incidents during boring and running wells are avoided owing to improved parameters of grouting cement, in particular increased sedimentation stability of mortar, dimensional stability and needed strength of cement stone at low positive and negative temperature in early hardening stages are achieved at simultaneous lowering of grouting mortar density.
EFFECT: improved performance characteristics of grouting mortar.
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FIELD: oil and gas production.
SUBSTANCE: invention relates to grouting mortars used for cementing casing pipes of gas, gas-condensate, and oil wells complicated by presence of formations with low hydraulic rupture pressure as well as presence of permafrost rocks. Light-weight grouting mortar contains 47.0-60.0% special-type cement, 6.6-11.8% clinoptilite as light-weight additive, and water. As a result, casing-pipe annulus incidents during boring and running wells are avoided owing to improved parameters of grouting cement, in particular increased sedimentation stability of mortar, dimensional stability and needed strength of cement stone at low positive and negative temperature in early hardening stages are achieved at simultaneous lowering of grouting mortar density.
EFFECT: improved performance characteristics of grouting mortar.
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