SU1361310A1 - Method of operating a gas-condensate or gas-oil well - Google Patents

Abstract

The invention relates to the oil and gas industry and m. used on gushing marginal; gas condensate or gas oil wells. The purpose of the invention is to increase the productivity of the well and remove its fountain operation. Periodically shut off the gas-liquid flow in the flow line using the valve of the shut-off valve. Dilution waves are formed in the wellbore. The period of overlapping of the gas-liquid flow to the amplitude of the rarefaction waves in the wellbore is determined from the expressions Г-г2л | Pr, "(ird. H-Pp-T O, 8l) / (4Q-P, -T, p. Z); And iP AOP P1-e), where T is the period, s; And - pressure amplitude, MPa; d is the internal diameter of the well, m; H - height, m; Рр - working pressure, MPa; T - absolute t-ra, K; O.C. flow rate under normal conditions, m / h; PQ - absolute pressure, MPa; TCO is the average mixture temperature. TO; Z is the super compressibility factor; L Rddr - depression on the reservoir, MPa; RGr, - criterion Frouda mixture. In order to implement the long-term method, a prerequisite is to create a pressure amplitude A that exceeds the total pressure loss in the well, 2 sludge. (L co 05

Description

one

The invention relates to the oil and gas industry and can be applied to low-flow gas condensate or gas-oil wells, as well as wells operating in the periodic gas lift mode with a working agent deficit (gas), to increase their productivity and extend the life by creating rarefaction waves. in gas-liquid mixture.

The purpose of the invention is to increase the productivity of the well and lengthen the life of its fountain operation.

FIG. 1 shows a diagram of a method for operating a gas condensate or gas-oil well; Fig.2 scheme of operation of the gas-lift well with a shortage of the working agent.

The method is implemented as follows.

On the flow line 1 of the well, an automatic shut-off valve 2 is installed and connected to the control panel 3, which controls the operation of the shut-off valve in the period back to the amplitude depending on the dynamic characteristics of the wells, defined by parameters such as , the structure of the flow of gas-liquid mixture, its velocity and flow rate gas content, as well as the pressure difference in the reservoir and at the bottom of the well (RD - -). When receiving the control panel signal for closing, the valve of the shut-off valve performs a relatively slow (in order to avoid water hammer) shut-off of the gas-liquid flow on the flow line. At this time, the reservoir and bottomhole pressures are equalized to a predetermined value in the well, as well as a change in the movement patterns of the gas-liquid flow and its structure (liquid plugs in the form of pistons are larger than with constant sampling), which in turn contributes to a better removal of fluid from the well at the time of exposure to the rarefaction wave. The valve cut-off valve is then opened, and this allows for the creation of pressure pulses that propagate in the form of rarefaction waves along the length of the well at the speed of sound, which carry the flow of gas and liquid and rises to the surface. Pulse appearance613102

The pressure is explained by the alternation of fluid and gas plugs moving at almost the same speed, but with different kinetic energy due to a large difference in specific gravity, and the frequency of these pulsations corresponds to the alternation of fluid and gas plugs, and the amplitude depends on the flow rate mixture, its structure and gas consumption. The propagation of rarefaction waves in a gas-liquid mixture is accompanied by phase transformations (gas is released from the liquid), which contribute to the occurrence of significant pressure drops, significantly exceeding the absolute value

2Q hydrostatic pressure. In order to form such an amplitude of pulsations that corresponds to the maximum outflow of fluid from the bottom of the well, it is necessary to determine the period of overlap of the discharge loop, which will be different for each well and determined by the formula (1):

  lid H Рр-Т „0.81 30 Т Л -. (1, -Р, .Т, р. Z 5

A rdel 0's

(About (2)

period, with;

pressure amplitude, MPa; borehole internal diameter, m; well height, m;

0

- -Z 0, 81 5 Rdep

R - R - Pi Zab

working pressure in the well, MPa;

absolute temperature. TO; well flow rate under normal conditions, m / h; absolute pressure, MPa; average mixture temperature, K;

supercompressibility coefficient;

empirical coefficient taking into account the presence of fluid in the well;

the magnitude of the depression on the reservoir, MPa;

with

- criterion Frouda mixture;

with -0-tsrO Tcp Z d Pp-To

- velocity of gas-liquid flow, m / s;

f 9.81 — free fall acceleration, m / s.

Formulas (l) and (2) have been experimentally obtained by studying the effect of the amplitude and frequency of rarefaction waves on the outflow of fluid from a well.

The physical meaning of the formula (O, which reflects the magnitude of the required periodicity for the formation of a rarefaction wave, consists in determining the time during which the bottomhole pressure increases (after overlapping the tubing section) to a value that would provide the required pressure amplitude, which is determined, B turn , according to the formula (2).

Formula (2) contains the amount of pressure by which the bottomhole pressure must be changed to form a rarefaction wave for a given structure and the flow rate of the gas-liquid mixture in the tubing,

Studies show that for the numbers RGp 4, t, e, in the area of the annular flow of gas-liquid mixture, the required amplitude of the rarefaction wave is close to LRdep Pp, - P smaller values of the gas velocity (Ph, d "4), when the structure of the flow is magnitude increases.

Therefore, to implement the method, a prerequisite is to create a pressure amplitude A that will exceed the total pressure losses in the well, consisting of friction losses D and gravitational losses due to the presence of liquid and gas LRrr in the well, but the amplitude cannot be larger existing in well bore

U Rdeo 5 A and d RTR

Rdep i

Tr t &,

Therefore, if the well is closed for a shorter period of time than calculated by formula (1), no amplitude is formed in the well. the required size and the fluid plug will not be lifted to the surface. If the time to overlap the wellbore is longer than the calculated one.

five

61310

anyway, the magnitude of the amplitude will not exceed Pden, the total time of just the well will be very large, which, in turn, will reduce its performance and thus will not allow to achieve the purpose of the invention.

An example, a sequence of 10 operations is as follows:

1. According to the nomogram, the O. well productivity is 2.25 m / s,

2. From the geological and technical report take data:

15 well height H 3015 m;

diameter - production string d 0,114 m;

well temperature t 15 С; supercompressibility coefficient 20 Z 0,8;

pressure at the wellhead P ,,,. 5.0 MPa;

bottomhole pressure, 9.2 MPa;

25 pressure in the wellbore of 14.3 MPa,

3. Calculate the working pressure in the well:

p - 2

+ RNST 7

MPa,

five

0

4, Calculate the average temperature in the well:

T t + 273 K 288 K,

5, Determine the magnitude of the depression in the formation:

Rde. RPP - ReaB 5.1 MPa,

6, Determine the velocity of the gas-liquid stream:

TCP-Z

p-t:

R

 2.71 m / s.

five

si:

0

The criterion determined by Froude is 6.57,

-. 8, Calculated by the formula (1)

well shutdown time: T d H-Pp TO 0.81

4 QH Po

TCP-Z

901.3 seconds

five

or 15.03 min

9, Calculate according to the formula (2) the amplitude of the control action on the formation:

- A & R,

d, en

.-- gd Pr-cm l

(1st) 5.08 MPa.

By reducing the pressure at the wellhead to a value equal to the pressure

in the collector (5.0 MPa), the valve-cutter closes the flow area of the flow line of the well. As a result of this operation, bottomhole wellhead pressure increases to a value of 14.3 and 10.8, respectively.

After reaching the specified pressure ;; The slam-shut valve opens the flow area of the tubing, and the fluid plug, which is under a pressure gradient of 5.08 MPa, is carried by a vacuum wave to the surface. Meanwhile, the total pressure loss in the wellbore is reduced by the amount of the removed liquid column. This leads, at constant reservoir pressure, to a corresponding increase in well production.

Claims (1)

Claims The method of operating a gas-condensate or gas-oil well, including periodically shutting off the gas-liquid flow in the flow line using a shutoff valve and boring the dilution waves in the wellbore, in order to increase the well productivity and lengthen the life of its wellhead , the period of overlapping of the gas-liquid flow and the amplitude of the rarefaction waves in the wellbore is determined from the expressions -J  .g R / um enws 1310 ird Н-Рр-То-0,81 Рн Ро-Тер Z 1 ). 0 five where T is the period, s; A - amplitude, MPa; d - well internal diameter, m i Н - well height, m; - working pressure in the well, MPa; TD - absolute temperature. TO; Qy - well flow rate in normal conditions, m / h; - absolute pressure, MPa; R T  R 0 five - average mixture temperature, K; Z is the super compressibility factor; 0.81 - empirical coefficient taking into account the presence of fluid in the well; iRdep P „. - P - the magnitude of the depression on For B layer, MPa; ye Fr - - Froude mixture test; 0 8a 40 - p. T -Z W in the rate of gas-liquid l O Q I l /  foot flow, m / s; g 9,81 - acceleration of free fall. no, m / s. G -n-j U VjKeNM l ; txt3 7P Th rf. H.rt   , ipuy.1 Editor A. Vorovich Compiled by V. Boriskina Tehred A. Kravchuk Proofreader S. Cherni Order 6204/36 Circulation 533 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul. Project, 4