CN1273817C - Variable speed supercharge oil well cement consistometer and thickening time measuring method thereof - Google Patents

Abstract

The present invention relates to a method for preferably simulating and measuring oil well cement slurry, the consistency and the thickening time thereof under the condition of different well depths and different pouring and replacing flows. The present invention solves the problem the measured consistency and thickening time of the oil well cement slurry not accords with underground practical situations. The present invention adopts a variable speed and pressurization type consistometer device as a measuring instrument; the rotary speed of a slurry cup is not the constant value 150RPM specified by API standard, and the change range of nonpolar speed adjustment and rotary speed is 10 to 600RPM. The method can determined the annular shearing rate of oil well cement slurry according to the annular pouring and replacing speed and the rheological property of oil well cement slurry; then, the average shearing stress and the average shearing rate during the rotation of special blades of a consistometer can be determined according to an experimental method and theoretical analysis; finally, the slurry cup simulation rotary speed of the measured thickening time of cement slurry can be determined. The rotational velocity and the thickening time determined and measured by the present invention can be used as the reference of the total time design of pouring cement construction. The present invention can ensure the agglutination of cementing engineering safety construction and consolidation well wall and the sealing insulation quality.

Description

Speed change booster-type oil well cement paste consistometer and the measuring method of thickening time thereof

Affiliated technical field:

The present invention relates to a kind ofly can simulate preferably and measure oil well cement paste and replace under speed and the shear rate situation, measure the method for its denseness and thickening time at different well depths and different notes.It is applicable to operations such as oil, gas drilled hole, well cementation, squeeze method, cementing plug.

Background technology:

In oil, gas prospecting drilling well, bored thousands of meters well depths after, fixed, the packing borehole wall prevents that rock caves in the well, is to increase oil, gas well life-span, improves the key technical problem of oil, gas well productive capacity.Technical term fixed, the packing borehole wall is referred to as casing and cementing.Casing and cementing is with in the sleeve pipe servant well, with oil well cement paste sprue bushing endoporus, replaces the annular space to the borehole wall and sleeve pipe again, solidifies the back fixed borehole wall (abbreviation cementing).The cementing process, grout self is wanted retrogradation, and is improper as its consistency change and corresponding thickening time design, causes grout can not reach the precalculated position, causes the failure of casing and cementing.

At present, the denseness of oil well cement paste and thickening time are by the API unified standard, use the booster-type consistometer to measure and design.This instrument simulates temperature, pressure and the axia flow situation of oil well cement paste in the down-hole, measures in rotary manner, and its rotational speed is 150RPM.The thickening time of grout is in its measuring process, and the time when moment of torsion reaches 2080g-cm, flowability has been lost in the multiviscosisty of grout this moment, and its consistometric value is 100Bc.In fact, oil well cement paste is according to construction requirement at the notes of down-hole for speed and shear rate, might not all press the suitable rotating speed 150RPM of API prescribed by standard.Therefore, oil well cement paste denseness of being measured and thickening time can not be reflected the down-hole actual conditions fully, might influence the cement mantle quality, even cause the danger of cementing job failure.

Summary of the invention:

In order to overcome the deficiency in the existing cementing job technology, solve oil well cement paste denseness and thickening time and the inconsistent problem of down-hole actual conditions measured, special a kind of speed change booster-type oil well cement paste consistometer and the measuring method of thickening time thereof of proposing.

The technical solution adopted for the present invention to solve the technical problems is: different annular injections replaces under speed and the shear rate situation in the down-hole according to oil well cement paste, its denseness and thickening time are measured, it is stepless speed regulation that consistometer slurry cup simulates rotating speed, and the rotation speed change scope is 10～600RPM.

Concrete technical scheme is:

1. replace speed and rheological characteristics according to oil well cement paste at the notes of annular space, determine the annular space shear rate of its liquid.The relevant calculation formula of annular space shear rate is:

${\mathrm{\γ}}_{\mathrm{an}}=\frac{12V_{\mathrm{CP}}}{D_h-d_c}\left(\frac{2n+1}{3n}\right)$

2. according to experimental technique and theoretical analysis, average shear stress and average shear rate when determining the special paddle rotation of consistometer.The pass that average shear stress and paddle are measured moment of torsion constantly is

$\mathrm{\τ}=\frac{1}{265.47}M\×{10}^5$

The average shear rate of paddle is

${\mathrm{\γ}}_{\mathrm{Cts}}=1.2\frac{0.20944}{n[1-{\left(\frac{r}{R}\right)}^{\frac{2}{n}}]}N$

γ _CtsBe equivalent to Fann-50 type rotational viscosimeter, during outer inner core radius ratio R/r=1.0678,1.2 times of inner tube wall shear rate.For consistometer, γ _CtsReflected the paddle diameter d _LeThe shear rate at=70.675mm place, its slurry cup and the outer diameter ratio of paddle $\frac{D_{\mathrm{cu}}}{d_{\mathrm{le}}}=\frac{74.6}{70.675}=1.0555.$

3. according to the axial shear rate γ of liquid _AnThe rotational shear speed γ that simulates with it _CtsThe principle that equates is determined under the different well ' s conditions, measures cement consistency and the slurry cup of thickening time simulation rotating speed, and relevant concrete numerical value is listed in the table 1;

$N=5.73n[1-{\left(\frac{r}{R}\right)}^{\frac{2}{n}}]{\mathrm{\γ}}_{\mathrm{an}}$

According to the API standard joining paste-making method and other running program, measure the denseness and the thickening time of oil well cement paste.

Annotate: symbol description, γ _An---grout is at the shear rate of annular space, S ^-1V _CP---grout is at the mean flow rate of annular space, cm/S; D _h---borehole diameter, cm; d _c---cover external diameter of pipe, cm; N---grout liquidity index; τ---grout is at the average shear stress at paddle place, dyn/cm ²M---measure the moment of torsion of grout, N-cm; γ _Cts---during the rotation of consistometer slurry cup, the average shear rate of paddle, S ^-1N---consistometer slurry cup rotating speed, RPM.

Speed change booster-type oil well cement paste consistometer involved in the present invention, mainly formed by high temperature and high pressure kettle, paddle and slurry cup, motor and torque sensing system, computer data processing system, its architectural feature is: the kettle lower end has the magnetically-actuated rotating shaft of stationary seal, and the disk of fixing slurry cup is housed on this; Tested grout and paddle are gone into the slurry cup, and be placed on the autoclave turntable shaft, and paddle shaft links to each other with the measuring spring that is fixed on kettle, is entrenched togather, and paddle is made up of three groups of parallel frame blades (aa, bb, cc) and perpendicular two groups of parallel blades (dd, EE); Electric machine speed regulation drives the slurry cup and reaches liquid in rotation successively, and paddle and spring are reversed by magnetically-actuated, produces moment of torsion, and slurry cup rotating speed returns speed and shear rate according to mine water mud, can change in 10～600RPM; Tested grout on the computer data processing system display screen, reflects the consistometric value and the corresponding change curve (as Fig. 2～5) of different grouts constantly by temperature, pressure, rotating speed of setting and the transmission of measuring moment of torsion.

The present invention and the employed pressurised oil cementing slurry for well of prior art API standard consistometer relatively have the following advantages: (1) consistometer slurry cup rotating speed is not constant 150RPM, but according to oil well cement paste in the flow rate and the shear rate of annular space, determine suitable with it rotational speed, record its thickening time, with foundation as the design of cementing practice T.T., thus the gluing and the pack quality of the assurance casing and cementing safe construction and the fixed borehole wall; (2) can study different slurry cups and simulate rotating speed and dissimilar oil well cement paste denseness and the relation of thickening time, determine the concrete grammar of the safe construction standard and the raising grout bonding capacity of different mortar architectures.

Table 1 is measured cement consistency and the suitable rotating speed of thickening time

Description of drawings:

The present invention is further described below in conjunction with accompanying drawing, implementation step and example.

Fig. 1 is a speed change booster-type oil well cement paste consistometer synoptic diagram of the present invention, among the figure: 1. high temperature and high pressure kettle, 2. slurry cup, 3. paddle, 4. well heater, 5. supercharger, 6. magnetically-actuated rotating shaft, 7. motor, 8. spring, 9. torque transfer, 10. pressure transmission, 11. the temperature transmission, the transmission of 12. rotating speeds, 13. data processing.

Fig. 2 is the thickening time curve under the different rotating speeds, the grout prescription: G class g cement+35% silica sand+1.5%HS-2A+0.5%SXY+0.5%HS-R (density p _c=1.90).

Fig. 3 is the thickening time curve under the different rotating speeds, the grout prescription: G class g cement+35% silica sand+1.5%HS-2A+1%SXY+0.5%HS-R (density p _c=1.89).

Fig. 4 is the thickening time curve under the different rotating speeds, the grout prescription: G class g cement+35% silica sand+1.5%HS-2A+1%SXY+0.2%HS-R (density p _c=1.905).

Fig. 5 is the thickening time curve under the different rotating speeds, the grout prescription: G class g cement+WZ30%+3%LT-2+0.5%SXY+0.2%HS-R (density p _c=1.4).

Embodiment:

The grout for preparing is contained into slurry cup 2, and paddle 3 is put the people starch in the cup 2, and then the slurry cup 2 and the paddle 3 that will fill grout put into high temperature and high pressure kettle 1 together, and build kettle cover; According to experimental pressure, temperature and the heating rate of well depth condition setting slurry, regulate automatically and control by well heater 4 and supercharger 5; According to down-hole annular liquid shear speed size, adopt the rotating speed formula, the data of reference table 1, the experiment rotating speed of definite slurry cup 2, the arrangements for speed regulation and the torque switch 8 that start motor 7 carry out experiment with measuring; Log-on data disposal system 13 by temperature transmission system 11, pressure transmission system 10, torque transmitting system 9 and rotating speed transmission 12, writes down the different consistometric values constantly of grout automatically; When the cement consistency value reaches 100Bc, the rotational speed regulation switch 7 of disable motor, torque measurement switch 8 and heater button 4, and lay down pressure in the kettle 1 by supercharger 5; When temperature in the kettle 1 is reduced to below 45 ℃, shed kettle cover, take out slurry cup 2 and clean, finish whole test work; From data processing 13, take out the record experimental data, analyze cement consistency and the experimental result of thickening time.

Carry out following instantiation according to the aforesaid operations method:

1. according to the oil well cement paste of four kinds of different performances of API standard preparation, its density is about 1.40 and 1.90 (seeing Table 2);

2. according to well depth 2000～4000m, set the experimental temperature and the pressure (table 2) of oil well cement paste;

3. according to the 150RPM of API standard code and selected in addition 70,100,300RPM, use speed change booster-type consistometer of the present invention, record the multiviscosisty curve and the thickening time (seeing accompanying drawing 2～5, table 2) of oil well cement paste.

The different grouts of table 2 are in the thickening time of different rotating speeds

Sequence number	Density	Temperature ℃	Pressure MPa	Slurry cup rotating speed RPM
							70 (100)	150	300
				1	1.90	112				76.4	2∶57	2∶27	2∶04
2	1.89	96	60				(6∶56)	5∶40	3∶50
				3	1.905	96				60	3∶50	3∶08	2∶34
4	1.40	60	30				4∶52	4∶12	3∶30

By table 2 and Fig. 2～5 as can be known:

(1) different cement slurry properties, thickening time shorten with the increase of rotating speed, and the thickening time that records according to 300RPM is than API standard code 150RPM institute's survey time, the shortest minimizing about 1h; (2) as the cement slurry thickening time that records with consistometer foundation as the design cementing practice time, and when grout the flowing velocity of annular space and shear rate be higher than consistometer slurry cup 150RPM related parameter is arranged the time, grout will be shorter than the thickening time that the API regulation records in the actual thickening time of annular space, and multiviscosisty in advance will cause the danger of cementing job failure; (3) be lower than the related parameter that has that consistometer is starched cup 150RPM as grout in the flowing velocity and the shear rate of annular space, grout will be longer than the thickening time that API standard code records in the actual thickening time of annular space, and well multiviscosisty and solidifying causes that oil, the air water of grout process of setting scurried problem; (4) whether the thickening time of different mortar architectures necessarily shortens with the increase of shear rate and suitable rotating speed, the further research of still needing.

Claims (3)

1, a kind of speed change booster-type oil well cement paste denseness and the measuring method of thickening time thereof, it is characterized in that: earlier the grout for preparing is contained into the slurry cup, paddle is put into slurry cup, and then the slurry cup and the paddle that will fill grout are put into high temperature and high pressure kettle together and are built kettle cover; According to experimental pressure, temperature and the heating rate of well depth condition setting slurry, regulate automatically and control by well heater and supercharger; According to down-hole annular liquid shear speed size, adopt the rotating speed formula to determine the experiment rotating speed of slurry cup, the arrangements for speed regulation and the torque switch that start motor carry out experiment with measuring; The log-on data disposal system by temperature transmission system, pressure transmission system, torque transmitting system and rotating speed transmission, writes down the different consistometric values constantly of grout automatically; When the cement consistency value reaches 100Bc, the rotational speed regulation switch of disable motor, torque measurement switch and heater button, and lay down pressure in the kettle by supercharger; When temperature in the kettle is reduced to below 45 ℃, shed kettle cover, take out the slurry cup and clean, finish whole test work; From data handling system, take out the record experimental data at last, analyze cement consistency and the experimental result of thickening time.

2, measuring method according to claim 1 is characterized in that: replace speed and rheological characteristics according to oil well cement paste at the notes of annular space, determine the annular space shear rate of its liquid; According to experimental technique and theoretical analysis, average shear stress and average shear rate when determining the rotation of the special paddle of consistometer; According to axial shear rate of liquid and the principle that the rotational shear speed of its simulation equates, determine under the different well ' s conditions again, measure cement consistency and the slurry cup of thickening time simulation rotating speed; Last joining paste-making method and corresponding operating program, the denseness and the thickening time of measuring oil well cement paste according to the API standard.

3, a kind of consistometer of implementing described cement consistency of claim 1 and the measuring method of thickening time thereof, mainly form by high temperature and high pressure kettle, paddle and slurry cup, motor and torque sensing system, computer data processing system, it is characterized in that: still cup lower end has the magnetically-actuated rotating shaft of stationary seal, and the disk of fixing slurry cup is housed on this; Tested grout and paddle are put into the slurry cup, and the slurry cup is placed on the autoclave turntable shaft, and paddle shaft links to each other with the measuring spring that is fixed on kettle, and paddle is made up of three groups of parallel frame blades and two groups of perpendicular parallel blades; Electric machine speed regulation drives the slurry cup and reaches liquid in rotation successively, and paddle and spring are reversed by magnetically-actuated, produces moment of torsion, and slurry cup rotating speed returns speed and shear rate according to mine water mud, can change in 10～600RPM.

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