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5THE SUPPRESSION OF THE PRODUCTION WELL BY CONTROLLING THE MOVEMENT OF FORMATION WATERS WITH THE USE OF SURFACTANTS
Akramov Bakhshillo Shafievich Umedov Sherali Khallokovich Naubeev Temur X Nuritdinov Jaloliddin Fazliddin ugli Komilov Tolib Olimovich
Tashkent state technical university named after Abu RayhanBeruni
Abstract. The article considers the issue of combating the production well by controlling the movement offormation waters with the use of surfactants.
The proposed method is a preventive measure to regulate the promotion of formation waters foam, this is meant to reduce the inflow of poplatkov and bottom waters by periodic impacts on the bottomhole formation zone with foam.
The options proposed injection foam pre-formed on the surface of, or injection into the reservoir of the accepted volume of an aqueous solution offoaming agent and injection of the required amount of air (gas), i. e. by the formation offoam in the reservoir.
Keywords: surfactant, regulation, movement of water, reservoir conditions, well, isolation of the water aerator, air compressor, water solution
One of the main complications in the extraction of hydrocarbons is the production well. In order to combat flooding are different ways of waterproofing works. Along with this is an important method of regulating the movement of formation waters with the use of surface-active substances.
Pen is not plugging material, such as cement, and therefore, it cannot isolate the flow of water. The penetration of foam in a porous medium can only impede the progress of water and time to reduce the inflow poplatkov and bottom water in the oil and gas wells in which the product it contains.
Usually after the injection of foam in the bottom zone of the reservoir, oil production rate increases and water decreases. Subsequently with the gradual growth of the water cut increases, and the decrease in oil production until initial, can repeat injection of foam.
Thus, the recommended method is not a method of isolation of water, and is a preventive measure to regulate the promotion of formation waters foam, this is meant to reduce the inflow of poplatkov and bottom waters by periodic impacts on the bottomhole formation zone with foam.
Well, products which obvodnaya foreign waters (upper, lower), can't serve, of course, object to regulation of their promotion foam. It seems to us that before the accumulation of relevant experience the degree of water production wells may not be an obstacle for injection of the foam into the reservoir. It is very important to carry out complex investigations in the borehole before and after injection of the foam. This will allow to more objectively assess the possibilities of this method and identify ways to further improve it. Such research in the first place to include inspection of the bottom hole, measure downhole and formation pressure, determining the inflow of water, specification of the production rates of oil, gas and water.
If the flow of water comes from the multiple layers productive of the section, dip tubing should be to the bottom of the perforations or to the middle of the bottom obodovskaya interlayer. In the case of water flow from one interlayer of the tubing is immersed slightly above the soles of hisYes, the injection of foam in the tube pump of 1.5-2.0% aqueous solution of foaming agent in the amount of 2-3 volumes of a pipe with the open valve on the annulus for cleaning the internal surface of pipes from oil, as oil is a defoamer. Then when you close the valve on the annulus into the reservoir pump m3 also 3-4 1,5-2,0% aqueous solution of foaming agent to displace into the reservoir formation water and the film of oil. In addition, penetrating into a porous medium, an aqueous solution of the foaming agent reduces the strength of the formed on a solid surface hydration layers and partially destroys them. After that start to inject the foam into the reservoir. If you develop the pressure exceeds the allowed column, it should be applied to the packer.
The efficiency of the process depends mainly on the method of formation of foam (on the surface or in the reservoir), the volume of the injected foam, aeration rate, foam stability.
Pumping foam into the formation can be done in two ways;
a) injection into the bed is pre-formed on the surface of the foam;
b) injection into the bed of the accepted volume of an aqueous solution of foaming agent and injection of the required amount of air (gas), i.e. by the formation of foam in the reservoir.
Accurately determine the scope of each method, foaming is not possible, as yet no sufficient experience. At this stage of development of works on regulation of the promotion of formation waters foams can recommend:
- with a formation pressure below hydrostatic in the reservoir should be pumped foam, preformed on the surface, especially when the level of liquid in the well is low;
- with a formation pressure equal to the hydrostatic and permeability more than 200 millidarcy foam for injection into the reservoir should also form on the surface;
- with a formation pressure equal to or above hydrostatic and a permeability of less than 200 millidarcy foam should be formed directly in the reservoir by pumping an aqueous solution of foaming agent and air (gas).
In field conditions, of course, can beat a lot of cases requiring deviations from this scheme. For example, when formation pressure of 0.3-0.4 at hydrostatic makes sense, apparently, the entire liquid column in the well to replace the foam with the degree of aeration, at which there is no flow of liquid and gas from the reservoir. Under this option, in our opinion, the process efficiency should be higher. Moreover, the foam can be pumped simultaneously in the pipe and annulus. When the liquid level in the well is very low and even fails to replace the liquid to the foam, it is advisable after 3aKanKH3-4 m3 1,5-2% aqueous solution of foaming agent pumping pre-formed on the surface of the foam. It is obvious that the formation of foam on the surface of its main parameter U resistance can be adjusted to maximize its value. In the formation of foam in the reservoir, the stability of its virtually unregulated. Therefore, it is necessary the adopted volume of aqueous surfactant solution pumped in several stages according to the following scheme; injection of the aqueous surfactant solution ^ injecti on of air (gas) ^ fix water surfactant solution ^ injection of air (gas), etc. the Number of cycles depends on the volume of aqueous surfactant solution and may be equal to 3-2.
The volume of the injected aqueous surfactant solution and air (gas) is directly dependent on the effective thickness of the reservoir, the fluid rate, percent of water production wells, reservoir permeability, reservoir pressure value.
To gain experience on regulation of promotion of formation waters can recommend the following volumes:
- with effective perforated bed thickness up to 20 m, flow rates up to 50 tons/day and water production up to 50% of the volume of aqueous surfactant solution can be taken equal to 20-40 m3;
- with perforated effective capacity of the reservoir from 20 to 50 m, the rate of flow from 50 to 100 t/day and water production from 50 to 80% of the volume of aqueous surfactant solution can be taken equal to 40-60 m3.
In other cases, i.e., when the thickness of the layer more than 100 m, well yields exceeding 100 t/day and water cut production more than 80%, the volume of aqueous surfactant solution may be equal to 60-80 m3.
The minimum degree of aeration ( ) at reservoir conditions should be at least 1.5-2.
Based on small experience of prospecting and industrial experiments, it is possible to recommend the following aeration rate (in normal conditions) depending on the reservoir pressure (table.1).
Table 1.
Formationpressureat The recommended degree of aeration (in normal conditions)
to 50 80
to 100 120
to 150 160
to 200 andmore 200
To achieve the degree of aeration of 1.5-2 in in situ conditions, you can increase the number of compressors at a constant flow rate or a gradual decrease in the flow rate when using a small number of compressors. For example, when the liquid flow rate of 3 l/h and aeration rate 80 (formation pressure up to 50 ATM), you will need two type compressor UKP-80. When the extent of aeration 200 and the fluid
flow of 3 l/h (formation pressure up to 200 ATM and more) you will need five compressors with capacity of 8 Nm3/min, with working pressure of 250-300 at.
It is therefore advisable at high degrees of aeration flow rate is taken equal to 1,0-1,5 l/sec. This condition, of course, does not apply to the case when the foam is formed in the formation by sequential injection of an aqueous surfactant solution and air (gas).
In the case of foaming in the reservoir, the injection of an aqueous solution of the surfactant is carried out in almost any flow of fluid, and the duration of compressor operation will be determined by the necessary volume of air (gas) to achieve a predetermined value of the degree of aeration.
Two schemes of sequential injection of an aqueous surfactant solution and air for the formation of foam in the reservoir:
1. formation pressure _ 120 at (the degree of aeration 130);
2. formation pressure _ 200 at (the degree of aeration 200).
It is assumed that there are two type compressor UKP-80 (capacity 8 Nm3/min, max pressure U 80 at) and four compressor type AX-8 (performance U 2 Nm3/min, max pressure U 250 at). Accordingly, the depth of wells _ 1200 and 2000 m. the Volume of the injected aqueous solution of the surfactant in both cases is equal to 40 m3.
When sequential injection of aqueous surfactant solution and air
(gas) either in the first case nor the second can not be applied
type compressor UKP-80. It can be used only in the first period to discharge air after the injection of the next portion of the aqueous surfactant solution to increase the pressure _ 70-80 at. Then stop the compressor UKP-80 and injected compressors type AX-8 (4 pieces) with a total capacity of 8 m3/min.
In the first case the reservoir must be pumped 5200 m3 of air, the second _ 8000 m3. Without the use of a compressor of the type UKP-80, if you have four compressors AX-8 for air injection into the reservoir will require, respectively, about 11 and 17 h. the Time of injection of the aqueous solution of the surfactant is relatively small and will amount to a total of no more than 2 hours (when fluid flow b l/s).
Because in the second case, i.e. with a formation pressure of 200 ATM and more type compressor UKP-80 is almost impossible to use it, you will have to work on fix plan using a compressor of the type AX-8.
The process of downloading in the first case can be reduced by using a compressor type UKP-80. In this case, the layer should not inject aqueous surfactant solution and foam with a low degree of aeration, and then the air to achieve a given degree of aeration ~~ 130.
The regulation of the promotion of formation waters foam to hold small volumes of aqueous surfactant solution (5-10 M8) and at low degrees of aeration (30-40) is inappropriate. The process efficiency is extremely low. In the presence of high pressure gas in the process of injection foam also can be greatly simplified. Given the search nature of the research, it is necessary in all cases to the preparation of the well to be made very carefully. In the absence of the possibility to satisfy the necessary conditions (the volume of pumping an aqueous surfactant solution and the degree of aeration), to begin work is not recommended, as large quantities of foam with a high degree of aeration is a critical factor in achieving positive results. Of course, the foam should have a maximum resistance. If the foam is unstable, even pumping it into the reservoir in large volumes will not give a positive result or the effect duration is short.
To obtain a stable foam is important to have the type of surfactant
and stabilizer and their concentration. What sort of resistance has had the foaming agent (meaning those which are industrially produced), the addition of stabilizer is essential. This condition associated with subject to complex physico-chemical environment of bottom-hole zone of the reservoir, which gets the foam. For example, in the process of drilling all the factors (the flow direction in the circulation, the factor of turbulence, the presence of particles of cuttings) increase the stability of the foam, and when processing bottom-hole formation zone in the production well some factors (presence of oil, water chemistry, etc.) can contribute to destruction of the foam. Therefore, the stability of the foam injected into the formation must be presented to the special requirements.
Good foaming agents are generally anion-active surfactants. Currently, the most available and relatively inexpensive is anion-active surfactant which saline water forms a more stable foam than with fresh water.
In this regard, in the formation of foam with the use of surfactants, it is advisable to fresh water add 2-3 % NaCl. Regardless, it is always necessary to use a stabilizer. Currently, the most affordable stabilizer is CMC,
It should be borne in mind that long storage of foam concentrate its activity reduced. It is
therefore necessary before injecting foam into the formation in the laboratory to determine the content of the active part is used for foaming surfactants.
Possibly a better foam to form on the basis of the formation water, as this can prevent swelling of clay particles included in the productive part of the reservoir. Such a result can be achieved if you apply gorkaltseva water. The quantity of ions CI in Ca2+ in water is determined in the laboratory. Thus, for cooking pans, you can apply mineralized formation and gorkaltseva water. In each case, should be conducted preliminary studies of the stability of foam in the laboratory. In addition, you should check the influence adopted for the formation of foam water on the swelling of clay particles contained in the perforated part of the reservoir. Hence, flow requirements for water quality: it should contribute to the formation of a stable foam and to prevent swelling of clay particles.
As blowing agents are soluble in water, the surfactant, the preparation of their aqueous solution in field conditions is not difficult. The dissolution of the stabilizer (e.g., CMC) in water takes place only after initial swelling. The duration of the swelling of CMC in water can be taken as 20-24 h.
The preparation of an aqueous solution of foaming agent with the addition of CMC is as follows. In advance, for two or three days before the injection of foam into the formation, in containers, of a capacity of 6-8 m3 soluble in heated to 400C water the required number of KMTS. For the complete dissolution within the specified time the solution is periodically agitated. The solution was then drained into a tank for delivery to the well. Well the CMC solution is evenly distributed throughout the volume of the injected aqueous solution of foaming agent.
For a better mixing of the aqueous solution-surfactant with air and more small bubbles, you need to use the aerator. In field conditions became widespread aerator pipe. It consists of two concentrically arranged one inside the other tubing with a diameter of 4 and 2*. Water with dissolved surface-active substance is pumped into the annulus between the 4 - and 2-inch pipes; air injected at the 2-inch pipe having a number of holes.
The number of holes in 2-inch pipe is determined from the equation:
n =
Q
0,122 • P
(1)
where p _ the number of holes;
Q ~ the amount of air injected into 2-inch perforated pipe, m3/day; 0,122 ~~ the performance of a single hole having a diameter d = 1.8 mm, m3/day;
R ~~ pressure on the compressor (on an air line of the bore), at.
Critical flow of air passing through small apertures, is found from the condition of absence of the merger of the bubbles, i.e. the bubble must be removed from the hole rather than he will the next bubble. If the bubble is removed from the aerator, floating in calm water, the maximum air flow through any opening can be approximately found by the following simplified formula:
qw = 104 T2
Com^
v MUH y
(2)
wherex is the radius of the hole, mm.
This equation is true when the value of holes equal to 3-4 mm.
If the water at the aerator moves and increases the rate of removal from it of bubbles, the air flow can be more than found by the formula (2).
The relationship between the hole size of the aerator and bubbles:
R = ^V^T (3)
whereRn the radius of bubble, cm; t -the radius of the holes of the aerator, cm;
S^.g. - surface tension at the boundary liquid-gas, Dean/see the Formula holds for t < 2 mm. In Fig. given the dependence of the pressure on the compressor (air-line) of the number of holes.
Fig.1. The dependence of the number of holes from the pressure on the compressor
The diameter of the holes should be taken equal to 1.5 and 1.6 mi (have in mind that due to the vibration of the drill the actual hole diameter is always somewhat greater), and the distance between the holes l= 10 mm. the Holes are placed on the pipe in a staggered manner.
On the discharge line of the compressor before connecting to
aerator avoid the ingress of liquid into the compressor, be sure to install a check valve. In addition, on the discharge line of the compressor, a safety device (in accordance with safety regulations).
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SURFACE SIMULATION, BASED AT PLANE SECONDARY
CURVES OF FINITE SUM
Prof. Vlasyuk G. G. associate prof. Spivak V. M. master Klimenko I. E.
Ukraine National Technical University of Ukraine "Kiev Polytechnic Institute"
Abstract. This article reveals the theme of creating effective computer-based methods for building surface. In comparison to the most commonly used approaches based on the Bezier curves and B-splines, the feature of the proposed method consists of using a discrete form of setting generatrices and guide curves, which results in reduction of computational time.
Keywords: computer-based methods, building surface, Bezier curves, B-splines, discrete form, guide curves, reduction of computational time.
The main objective is to construct a surface while minimizing the angles between the normal to the surface and the direction of the radar beams in the same point on the surface. The solution to this problem is based on the following geometric principles: - to solve the problem by means of
