SU1677278A1 - Method of bottomhole treatment - Google Patents

Abstract

The invention relates to the oil and gas industry, is intended for the physicochemical effect on productive formations and can be advantageously used in the late stage of exploitation of gas fields. The aim of the invention is to improve the processing efficiency of the bottomhole formation zone. The necessary volumes of reagents used are pre-prepared (gas condensate, methanol and foaming surfactant). According to a known technology, a buffer gas-liquid mixture is pumped into the well, for example, containing gas condensate and gas, a gas-liquid mixture containing methanol and a gas as a desiccant, a working gas-liquid mixture containing methanol, a TEA1-M foaming agent and a gas in a volume equal to the volume of the first part of the formation in the zone of high filtration rates, and press this mixture down with gas until the wellhead pressure is stabilized. The injection and push cycle of the working mixture is repeated in the same way. The number of cycles performed is determined by the specific geological and technical conditions of the method. After the last portion of the working mixture is pumped, the entire volume of the working mixture is pumped into the zone of liquid filtration rates, resulting in preservation in the bottomhole formation zone 1 for a longer time of the working mixture and an increase in the treatment efficiency of the formation, 1 mud. ON l V | YO VI 00

Description

The invention relates to the oil and gas industry, in particular to methods for processing the productivity of beds, and can be used mainly in the late stage of the development of gas fields,

The aim of the invention is to increase the processing efficiency of the productive formation.

The method is carried out as follows.

In a well with a closed annulus, gas carbonated condensate as a buffer liquid, carbonated methyl alcohol as a desiccant, carbonated methyl alcohol solution with a frother (working mixture), the volume of which is equal to the first volume, is pumped through the lift pipes.

spaces of the formation zone with high filtration rates, and pushing it with gas until the wellhead pressure is stabilized. Depending on the specific conditions (reservoir parameters, radius of the depression funnel, etc.), this cycle is repeated several times. After the end of the last injection cycle, the working mixture is forced by gas into the zone of low filtration rates of the formation.

Example. Initial geological and technical conditions in the well: depth of the horizon H 3374 m; working (effective) formation thickness pe 3.0 m; reservoir pressure 4.1 MPa; coefficient of effective porosity te 0.10; borehole diameter 0.3 m; radius of the power contour RK 200 m; length 2 1/2 tubing 3350m.

Based on the pressure distribution equation

 + pK2-p

.

Rk

1P RK / RC

where Pr is the pressure at the point of the formation at a distance Gu from the borehole wall;

Рк - reservoir pressure;

Рс - bottomhole pressure;

RK is the radius of the power contour;

Re the radius of the well, build a pressure distribution curve (see drawing) and determine the zones:

A - high filtration rates;

B - increased filtration rates in the reservoir;

B - low filtration rates.

The volume of the first space of the high filtration rate zone is determined. Zone A according to the formula:

t (p2. 0.1 0.4

2h

3.14

4 3,0

(72-0,32)

 4.6m3

where / is the coefficient of liquid displacement from the formation by gas or gas-liquid mixture, taken equal to 0.4.

12 m3 of gas condensate, 1.5 m of methyl alcohol and 6 m of methyl alcohol solution with TEAS-M foaming agent (5.8 m of methyl alcohol and 0.2 m3 of TEAC-M) are prepared at the rate of four injection cycles of the working mixture with a gas number (degree of carbonation) equal to two in reservoir conditions, i.e. to fill the volume V, take 1.5 m3 of methyl alcohol with TEAS and two volumes of gas (3 m3 with regard to the pressure in the reservoir, only 4.5 m of the working mixture at Vn - 4.5 m3.

The tubular space of the well is connected through an ejector to a pump assembly 4AM-700, and the gas line of the ejector is connected to the line of the gas distribution station.

With the annular space closed, 12 m of gas condensate is pumped into the elevator while simultaneously supplying gas to the ejector, after which the wellhead pressure is stabilized. The pressure during injection up to the ejector is Re up to 32 MPa, after the ejector Ptp 8 MPa, on the gas line Pr - 7

0 MPa.

After that, 1.5 m3 of moisture absorber (methyl alcohol) is pumped into the elevator with the closed annulus when gas is supplied to the ejector in order to reduce water saturation and filtration resistance during the subsequent injection of aerated alcohol solution of the frother.

Next in the elevator with the closed annulus pumped the first portion

0 1.5 m3 alcohol solution of TEAS-M in methyl alcohol when the gas is supplied to the ejector P $. ds 30 MPa, Rtr 7.5 MPa, Wg 7 MPa, and push it with gas from the plume.

The volume of gas for the sale of SHCs is calculated on the basis of at least two or three pore volumes taking into account p and is determined by the gas flow rate measured at the measuring site.

In this case, the three pore volumes of zone A according to the tubing volume are 23.8 m3.

0 Under the measurement conditions (P 8 MPa), the required volume of gas is 39 m3 and injected into the well in 30 minutes. Then a second portion (1.5 m3) of TEAS solution in methyl alcohol is pumped in when the gas is supplied to the ejector (Pz

5 to 30 MPa, Rtr 70.5 MPa, Pr 7 MPa} and push it with gas in the amount of 39 m, which is pumped over 40 minutes.

Under similar conditions, the third and fourth portions of the carbonated spray solution with a foaming agent are injected. Then, the portions of the carbonated alcohol solution of the frother outside the zone B by gas are displaced and displaced (3 pore volumes of zone B, taking into account the volume of tubing

5,264.4 m3). Under the measurement conditions of P 8 MPa, the required volume of gas is 430 m and was pumped into the well over 4 hours.

After the well was put into operation, the flow rate increased by 6 thousand m3 / day and works in

Claims (1)

0 for 4 months with a flow rate of 51 thousand m3 / day. Claims of Invention A method of treating a near-eaboy zone of a formation including sequential injection of a carbonated gas into a well. 5 condensate, carbonated solution of methyl alcohol with a foaming agent and pushing them into the formation, characterized in that, in order to increase the efficiency of formation treatment, carbonated methyl alcohol is injected into the carbonated solution of methyl alcohol with a foaming agent, and carbonated methyl alcohol solution with a foaming agent is pumped in portions, the volume of each portion is equal to the pore volume of the zone of the reservoir with the highest filtering speeds. gas, and the pushing is carried out by gas until the wellhead pressure is stabilized, while the last portion is forced into the zone with the lowest filter speeds pool 3.0 5 10 15 20 25 30 35 40 U5 iff R (M)