SU1350330A1 - Method of mud injection into permeable formations in wells - Google Patents

Abstract

The invention relates to the field of mining and allows for improved insulation quality. The clogging of permeable formations in the wells is carried out by preparing the suspension (C), pumping C into the reservoir in cycles, each consisting of pumping portions C and pause. The injection of C into the formation is carried out in a series of decreasing, but identical within batches in volume series. the consumption of injection and the duration of the pause cycles. The duration of the series is limited to achieving the speed C in the reservoir of values not exceeding twice the moving speed of the motionless particle. The initial portion C is chosen equal to the volume of channels of fluid movement in the zone of clogging, and the duration of the pause is not less than the settling time of particles in these channels. The cycles of the subsequent series are reduced in proportion to the value of the coefficient K, defined by the formula K (P,: /) P) x x (21gO: Q) :( 3,), GDe L and 7, are the differences between the reservoir and bottomhole pressures: initial and final for the previous series of cycles; Q; Q,) P, JP - respectively, the costs and differences of reservoir and bottomhole pressures of experimental downloads under the condition Q -TQ,. As an experienced downloads use, Zack. The contiguous cycles of the previous and subsequent series. 3 hp f-ly, 1 tab. (L has eaten about with

Description

one

The invention relates to the mining industry, in particular to methods for reducing the permeability of formations, and can be used both to eliminate absorption and to reduce inflows to wells.

The purpose of the invention is to improve the quality of the insulation.

The method is carried out as follows.

For the formation to be tested by known methods, reservoir pressure P is determined, power t,

1350330.

suspension rates in the reservoir, the values not exceeding twice the speed of moving of the fixed particle, from the ratio

“.

A / Trmn V,

,R.

ten

(X PAGE

For the selected value of K p, the parameters of the cycles for the second and subsequent series are determined using the formulas

,;

Q, -

the coefficient of active porosity or fracture n, the value of the opening of the crack-channels of fluid movement b, the angle of inclination to the vertical of the plane c /, as well as the hydraulic particle size V ,, and the speed of movement of the inert collar-particle by the fluid flow of the carrier particles V , Taking into account the objectives of colmatage pursued and the experience of previous works, choose the rad1-tus of the clogging zone K,

3

And the final bottomhole pressure P which should be achieved as a result of colmatation.

Calculate according to the formulas the volume of the initial portion of the suspension in the reservoir:

V,

OrderV, KP2 -

the initial flow rate of the suspension V,

Q, 4 // r

page

initial pause duration

T -2 - V sin5

Experimental injections into the collimated formation are carried out with costs-and Q and Q (with and), measured by well-known methods, downhole, pressure and P, respectively. The differences in reservoir and bottomhole pressures are determined.

. ; p "pn" ,.

Determine the exponent l:

iPl (QJ.) 2c. .

JP Q

Ig P / JP.

The value of the coefficient of proportionality is chosen to reduce the parameters of the cycles in the subsequent series (K p) from the condition of limiting

“.

A / Trmn V,

,R.

(X PAGE

For the selected value of K p, the parameters of the cycles for the second and subsequent series are determined using the formulas

,;

Q, -

T Pr - 1-1

t, to

where i is an index denoting the sequence number of a series of cycles. According to the found value a and selected K, taking into account the fact that the bottomhole pressure (r.), Initial for the first series of cycles, at the injection rate

I p

Q is equal to the pressure at experimental injection P, the final value for the first series of pressure cycles (P-fi;) is determined from the ratio

3.25

0

TO,

from where

R

 ) PIK

1k

TO

etc

-. w

IsPi / sE

0

I l. R., + JP,.

Then one: of known methods, the suspension is prepared and pumped into the clogged formation in equal cycles (with parameters V, Q, T), controlling the growth of the bottomhole pressure.

C, the achievement of bottomhole pressure value Pj, go to the second series of cycles, reducing the parameters of the first cycle (V, 0 but the coefficient

T) is proportional to 2C (& 0).

50

V,

Having determined the value of the initial bottomhole pressure for the first cycle of the second series, the value 55 of the final for the second series of bottomhole pressure P c is calculated according to the formulas

12 / dP2H / 4P 1.

R2 li

R

2i

2k j, 3,

2H 2 /

In this manner, the collation process continues until the selected final bottomhole pressure of the RE is obtained.

Example (analytical calculation of the process of formation mudding by the proposed method).

Baseline: absorption zone interval 300-301 m; borehole diameter 300.0 mm; radius g 150 mm; absorption zone power m 1 mm; the coefficient of active fracturing, 0.15; reservoir pressure 250.5 mm of water. v .; filtration coefficient K 1, 16 cm / s 0,0116.m / s; the width of the fluid flow channels is 0.05 m; the angle of inclination of the plane of the crack to the vertical 90 is the average diameter d 50 of particles of a coagulating material (sand) 0.09 mm; the specific gravities of sand () and technical water (v) are 2.5 and 1.0 t / m, respectively.

Determine the average hydraulic size (V p) of the bonding agent particles, for example, by the formula

 V,., 27.79-Vd5, ()

for the accepted values of V, to 0.032 m / s and the speed of moving (Vj, p). According to the experimental data, as half of the critical (flushing) speed, the speed

 moving, 11 m / s.

The final bottomhole pressure RZ 300 mm water column, the radius of the zone of clogging R 2.0 m, the proportionality coefficient K „0.6, and the equivalent roughness K 2.0 mm 0.002 m.

The value of the correlation coefficient K is determined by the formula, 3.97-10

Calculate the volume of the initial portion of the suspension V 1,873 initial flow rate of the suspension supply Qi g 0.031 MVc (take Q, 0.015 initial pause duration T, 1.6 s; the pause duration is determined from the technical capabilities of the equipment (by minimum time of stopping and starting the pump) and do not adjust.

The value of the constant factor C 0.368 is determined,

Calculate the hydraulic resistance of the Republic of Lithuania at op, 1 ton sluggings with flow rates Q p Q equal to 0.015 and 0.010 MVc, respectively:

lR 1.40 mm water;

AR 0.62 mm water column

The value of the exponent a is determined to be 1,000.

For the first series of cycles, final bottomhole pressures (P) are determined:

/ Ip

tk

 7.38 mm water line;

0

0

35

45

0

five

P, P ,,, 257.88, and the width of the flow channels

lb-CRC O, OZ m.

For the second series of cycles, the batch volume and injection rate are determined.

-K 1,124

, 009 MVc

and initial hydraulic resistance

, 65 mm water column

Calculate the value of the exponent a by the parameters of adjacent cycles in the first and second series:

, 000

For the second series of cycles, final bottomhole pressure is calculated.

, 96 mm water;

P P + jiPr, 26ft, 6 mm water column and the width of the flow channels

bj |, Ь К Р7Р 0,018 m.

Then, in a similar way, the parameters are calculated following the rx: series of cycles. The results of the calculations are shown in the table.

Claims (3)

1. A method of colmating permeable formations in wells by preparing a suspension, injecting the suspension into the formation in cycles, each comprising injection of portions of the suspension and pause, in order to improve the quality of the insulation, injection of the suspension into the formation is performed a series of diminishing portions of the same volume, injection rate and duration of pause cycles, and the duration of the series is limited to achieving a slurry speed in the reservoir of values not exceeding twice the moving speed of a stationary particle. 2. The method according to claim 1, which is different from the fact that the initial portion of the suspension is chosen to be equal to the reduction of the flow channels of the liquid in the zone of the ring S1350330 matatsii, a pause duration - not less time of sedimentation of particles of these channels. 3. The method according to claim 1, about tl and h y and the fact that the cycles after the series reduce the proportionality of the coefficient (K), is determined by the formula „, Pw. 3.2f. 1I y) where, RK differences reservoir and downhole; pressures. Injection Portion Volume V. Injection Rate &. Hydraulic Avar Scarce with, R {c m m / s t, 874 1.12 / 4 0.674 0.405 0.015 0.009 0.0054 0.003 LR 1 to Bottomhole pressure R., 1 TO Width of channels NIL b, Exponent a. MST, 1.40 2.65 5.03 9.52 7.38 13.96 22.44 50.08 mm water line-257988 264.46 276.94 300.58 m 0.03 0.018 0.011 0.006 1.001.001.00 Compiled by E. Molchanova Editor N. Bobkova Tehred A. Kravchuk, Proofreader A. Obruchar Order 5237/32 Circulation 533 Subscription VNIPGSH State Committee of the USSR for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 . Production and printing company, Uzhgorod, Projecto st., 4 Q, Q, I j, n and , R boundary for previous series of cycles; - respectively, the costs and differences of reservoir and downhole pressures, pilot pumpings, Р Р, 4, Method according to claim 1, with the use of the next cycles subsequent series of x. t, 874 1.12 / 4 0.674 0.405 0.015 0.009 0.0054 0.0032 0.03 0.018 0.011 0.006 1.001.001.00