CN102435536A - Method for testing rheological property of engineering slurry - Google Patents

Abstract

The invention discloses a method for testing rheological property of an engineering slurry, which comprises the following steps of: using a rotational viscometer to test the following parameters of the engineering slurry: plastic viscosity mu p of 3.2(theta 100 - theta 6), dynamic shear force tau d of 0.511 * theta 100 - 0.544(theta 100 - theta 6), and effective viscosity mu e of 100 theta 3. The rheological property of the engineering slurry is tested by the low rotation speed test method, so that the test accuracy is higher.

Description

The engineering drilling fluid rheology can method of testing

Technical field

The present invention relates to a kind of mud property method of testing, relating in particular to a kind of engineering drilling fluid rheology can method of testing.

Background technology

The viscosity of mud is to measure the physical quantity of liquid glutinousness size, and interactional size between its internal friction resistance and the inside is one of most important rheological parameter of mud during its reflection mud flow.Mud belongs to Bingham plastics, and its viscosity is divided into effectively (apparent) viscosity and plastic viscosity.The virtual viscosity of mud is made up of plastic viscosity and structural viscosity.

It is stable that the viscosity height of mud helps hole/cell wall, and native slag suspends/carry; Be unfavorable for dregs sedimentation and removing influencing operating efficiency but viscosity is too high.

The evaluation method of viscosity is a lot, and funnel viscosimeter and rotational viscosimeter are engineering mud viscometers relatively more commonly used.

Rotary viscosity of the prior art is multiple in respect of two speed, six speed, ten two-speeds and continuously variable etc.Two fast type rotational viscosimeters are with the shear stress of 600r/min and these two kinds fixing tachometric survey mud of 300r/min, and they are equivalent to 1022s respectively ^-1And 511s ^-1Shear rate.Six fast viscosity meters are present the most frequently used how fast type viscosity meters, and its six kinds of rotating speeds and corresponding with it shear rate are following: 600r/min (1022s ^-1), 300r/min (511s ^-1), 200r/min (340.7s ^-1), 100r/min (170.3s ^-1), 6r/min (10.22s ^-1) and 3r/min (5.11s ^-1).Ten two-speed rotary viscosity metering rotating speeds are 1,2,3,6,30,60,90,100,180,200,300,600r/min, continuously variable viscosity meter rotating speed is stepless adjustable from 1r/min to 600r/min.

Engineering mud flow specificity analysis:

Engineering mud is made up of clear water, bentonitic clay and the treating agent of a little usually; Its rheological characteristics can be used bingham's plasticity pattern description (formula 1 and 2), and the rheological characteristics parameter of estimating mud comprises virtual viscosity (also being AV), plastic viscosity, yield value and gel strength etc.

τ=τ _d+ μ _pγ formula 1

${\mathrm{\μ}}_e=\frac{\mathrm{\τ}}{\mathrm{\γ}}={\mathrm{\μ}}_p+\frac{{\mathrm{\τ}}_d}{\mathrm{\γ}}$ Formula 2

In the formula, τ is a shear stress, Pa; γ is a shear rate, s ^-1μ _pBe plastic viscosity, mPas; τ _dBe yield value, Pa; μ _eBe virtual viscosity, mPas.Virtual viscosity increases with shear rate and reduces.

In the prior art, the rheological property of petroleum drilling and used for geological prospecting mud is used two above-mentioned fast type rotary viscosity measurings always, and its rheological parameter is calculated as follows:

μ _p=θ ₆₀₀-θ ₃₀₀Formula 3

τ _d=0.511 (θ ₃₀₀-μ _p) formula 4

${\mathrm{\μ}}_e=\frac{1}{2}{\mathrm{\θ}}_{600}$ Formula 5

In the formula, θ ₆₀₀And θ ₃₀₀Be respectively the reading that rotating speed is 600rpm and 300rpm rotational viscosimeter, dimensionless.

There is following shortcoming at least in above-mentioned prior art:

Because the viscosity of engineering mud is very low, the high-revolving measuring method error of using in the prior art is bigger, and measuring accuracy is lower.

Summary of the invention

The purpose of this invention is to provide the high engineering drilling fluid rheology of a kind of testing precision can method of testing.

The objective of the invention is to realize through following technical scheme:

Engineering drilling fluid rheology ability method of testing of the present invention comprises with rotational viscosimeter the following parameter of engineering mud is tested: plastic viscosity, yield value, virtual viscosity;

μ _p=3.2 (θ ₁₀₀-θ ₆) formula 9

τ _d=0.511 * θ ₁₀₀-0.544 (θ ₁₀₀-θ ₆) formula 10

μ _e=100 θ ₃Formula 11

In the formula: μ _pBe plastic viscosity, mPas; τ _dBe yield value, Pa; μ _eBe virtual viscosity, mPas;

θ ₁₀₀, θ ₆And θ ₃Being respectively rotating speed is the reading of 100rpm, 6rpm and 3rpm rotational viscosimeter, dimensionless.

Technical scheme by the invention described above provides can be found out, engineering drilling fluid rheology ability method of testing provided by the invention, owing to adopted slow-revving method of testing can test the engineering drilling fluid rheology, test accuracy is higher.

Description of drawings

Fig. 1 is a cast-in-situ bored pile mud test rheological curve synoptic diagram in the embodiment of the invention.

1 is 3% bentonitic test curve; 2 is the test curve of 3% bentonitic clay+10% clay; 3 is the test curve of 5% bentonitic clay+11% sand; 4 is the test curve of 5% bentonitic clay+0.1CMC+0.25% soda ash; 5 is the test curve of 4% bentonitic clay+0.1CMC+0.2% soda ash+10% cohesive soil.

Embodiment

To combine accompanying drawing that the embodiment of the invention is done to describe in detail further below.

Engineering drilling fluid rheology ability method of testing of the present invention, its preferable embodiment is:

Comprise with rotational viscosimeter the following parameter of engineering mud is tested: plastic viscosity, yield value, virtual viscosity;

μ _p=3.2 (θ ₁₀₀-θ ₆) formula 9

τ _d=0.511 * θ ₁₀₀-0.544 (θ ₁₀₀-θ ₆) formula 10

μ _e=100 θ ₃Formula 11

In the formula: μ _pBe plastic viscosity, mPas; τ _dBe yield value, Pa; μ _eBe virtual viscosity, mPas;

θ ₁₀₀, θ ₆And θ ₃Being respectively rotating speed is the reading of 100rpm, 6rpm and 3rpm rotational viscosimeter, dimensionless.

Said rotary viscosity is counted of the prior art 12 fast rotational viscosimeters or continuously variable rotational viscosimeter.

Said engineering mud can be petroleum drilling and used for geological prospecting mud.

Because the viscosity of engineering mud is very low, the high-revolving measuring method error of using in the prior art is bigger, and the present invention has adopted slow-revving method of testing, and test accuracy is higher.

Can test the test effect of comparative analysis the application and prior art below by drilling fluid rheology:

1, mud can adopt the bentonitic clay preparation according to boring stratum difference; Also can use wash boring, utilize the stratum cohesive soil from making slurry (needing the admixture bentonitic clay during clay poor quality of stratum); For bad ground, need to add some treating agent mud's college educations.With ZNN-D6S type six fast rotational viscosimeters, several kinds of typical borehole bored concrete pile mud to be tested, experimental data is seen table 1, its rheological curve is seen Fig. 1.

Table 1 rheology testing

Can find out coefficient of determination R by Fig. 1 ²All near 1, the shear rate and the shear stress of cast-in-situ bored pile mud are linear, satisfy the rheological equation τ=τ of Bingham fluid pattern basically _d+ μ _pTherefore γ can judge that cast-in-situ bored pile mud is Bingham plastics.

2, drilling fluid rheology can evaluation method

The evaluation method of viscosity is a lot, and funnel viscosimeter and rotational viscosimeter are engineering mud viscometers relatively more commonly used.Funnel viscosimeter becomes the most frequently used viscosity test instrument because of its measuring method is easy, measurement result is called funnel viscosity, and s representes with the time.Funnel viscosity and other rheological parameter combine, and characterize the rheological of mud jointly.Funnel viscosity can not be made mathematics and handle as the data that record from rotational viscosimeter, also can't convert with other rheological parameter.Funnel viscosity can only be used for differentiating between operational period the trend that each stage viscosity changes, and it is the reason that changes of illustrative mud viscosity not, can not only can be as the scene as the foundation that mud is handled.

Rotary viscosity is in respect of two speed, six speed, ten two-speeds and stepless change etc.Two fast type rotational viscosimeters are with the shear stress of 600r/min and these two kinds fixing tachometric survey mud of 300r/min, and they are equivalent to 1022s respectively ^-1And 511s ^-1Shear rate.Six fast viscosity meters are the most frequently used how fast type rotational viscosimeters of petroleum drilling and geologic prospecting, and its six kinds of rotating speeds are following: 600,300,200,100,6 and 3rpm.Ten two-speed rotational viscosimeters have more six grades than six fast rotational viscosimeters, promptly 60,30,20,10,2,1rpm.Continuously variable viscosity meter rotating speed is from 1r/min to 600r/min (1.703s ^-1～1022s ^{- 1}) stepless adjustable.Viscosity meter rotational speed N and shear rate γ corresponding relation are γ=1.703N, see table 2.

Table 2 rotary viscosity metering rotating speed and corresponding with it shear rate

Because the cast-in-situ bored pile shear rate generally is not more than 100s ^-1, so rotational viscosimeter is when estimating the rheological property of mud, and it is more reasonable to test during less than 60rpm at rotating speed, and the calculating of rheological parameter utilizes the low shear rate reading.Therefore, among the application for cast-in-situ bored pile (comprising diaphram wall), but select ten two-speeds or electrodeless variable-speed rotational viscosimeter for use,

3, rheological parameter computational analysis:

The Bingham plastics rheological parameter comprises plastic viscosity (μ p), yield value (τ d), ratio of dynamic shear force/yield value to plastic viscosity, virtual viscosity (μ e) and gel strength (τ s).With six fast viscosity meter tests, its rheological parameter is calculated as follows:

${\mathrm{\μ}}_p=\frac{300({\mathrm{\θ}}_{N2}-{\mathrm{\θ}}_{N1})}{(N_2-N_1)}$ Formula 6

${\mathrm{\&tau;}}_d=0.511\&times;{\mathrm{\&theta;}}_{N2}-\frac{5.11({\mathrm{\&theta;}}_{N2}-{\mathrm{\&theta;}}_{N1})\&times;{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000096436190000011.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}{10(N_2-N_1)}$ Formula 7

${\mathrm{\&mu;}}_e=\frac{300{\mathrm{\&theta;}}_{N2}}{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000096436190000011.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}$ Formula 8

In the formula, μ _pBe plastic viscosity, mPas; N ₁, N ₂Be respectively two rotating speeds of six fast rotational viscosimeters, r/min; θ _N1, θ _N2Be corresponding rotational speed N ₁, N ₂Reading during r/min, dimensionless.τ _dBe yield value, Pa; μ _eBe virtual viscosity, mPas.

In petroleum drilling and geologic prospecting mud, N ₂And N ₁Get 600r/min and 300r/min respectively, computing formula is respectively μ _p=θ ₆₀₀-θ ₃₀₀, τ _d=0.511 (2 θ ₃₀₀-θ ₆₀₀), μ _e=0.5 θ ₆₀₀

Because the cast-in-situ bored pile aperture is big, mud is in cyclic process in the low rate of deceleration scope, the computing formula of need deriving again.By the experimental data of formula 6,7 and table 1, calculate plastic viscosity and yield value (seeing table 3) in each speed stage respectively, and, calculate the corresponding virtual viscosity (seeing table 4) of different rotating speeds respectively by formula 8 and table 1 experimental data.

The plastic viscosity and the yield value of table 3 different rotating speeds section

Virtual viscosity under table 4 different rotating speeds

Can find out that by data in table 3 and the table 4 the resulting plastic viscosity of different rotating speed section is different with yield value, have a long way to go between the virtual viscosity of different rotating speeds correspondence.Cast-in-situ bored pile stake footpath is big, and up-hole velocity is low, and shear rate is low, therefore can adopt 100～6r/min and two segmentations of 6～3r/min to come computational plasticity viscosity and yield value.But the result of calculation of 6～3r/min segmentation can be found out because exceptional value can appear in the precision problem of six fast viscosity meter instruments itself from table 3, so adopts 100～6r/min computational plasticity viscosity and yield value.Low shear rate scope (0～30s according to cast-in-situ bored pile mud ^{- 1}), adopt 3r/min to calculate virtual viscosity.

4, conclusion:

To sum up analyze, with 100r/min and 6r/min substitution formula 6,7, with 3r/min substitution formula 8, the computing formula of deriving plastic viscosity, yield value and virtual viscosity is following:

μ _p=3.2 (θ ₁₀₀-θ ₆) formula 9

τ _d=0.511 * θ ₁₀₀-0.544 (θ ₁₀₀-θ ₆) formula 10

μ _e=100 θ ₃Formula 11

Ratio of dynamic shear force/yield value to plastic viscosity is the ratio of Bingham plastics yield value and plastic viscosity, is used for characterizing the power of mud shear thinning behavior.By the result of calculation in the table 3, obtain the ratio of dynamic shear force/yield value to plastic viscosity (seeing table 5) of several kinds of typical borehole bored concrete pile mud.

The ratio of dynamic shear force/yield value to plastic viscosity of table 5 mud

It is relatively suitable that ratio of dynamic shear force/yield value to plastic viscosity is controlled at 0.36～0.48Pa/ (mPas), helps realizing plate laminar flow, reaches stabilizing borehole and effectively takes the purpose of slag.Can be found out that by data in the table 5 ratio of dynamic shear force/yield value to plastic viscosity of several kinds of typical borehole bored concrete pile mud is generally less than required value, ratio of dynamic shear force/yield value to plastic viscosity is significantly improved after adding XC, and viscosity and shear force also have increase in various degree.Be beneficial to and carry boring mud, and satisfy flat plate laminar flow and be beneficial to the stable of hole/cell wall.

5, concrete test case:

In view of wide-aperture cast-in-situ bored pile and diaphram wall mud; In cyclic process, be under the low-rate-of-shear rate condition; For obtaining the viscosity number of mud under the true environment condition, so adopt the electrodeless variable-speed viscosity meter that 6 representative assembly sides are tested, test result is as shown in the table:

Table 6 low shear rate test result

Annotate: 1#:3% bentonitic clay+0.2%Na ₂C0 ₃+ 30% Guan Village soil

2#:3% bentonitic clay+0.2%Na ₂CO ₃+ 20% Guan Village soil

3#:4% bentonitic clay+0.2%Na ₂CO ₃+ 11% sand

4#:5% bentonitic clay+0.2%Na ₂CO ₃+ 11% sand

5#:5% bentonitic clay+0.2%Na ₂CO ₃+ 0.1%CMC+11% sand

6#:4% bentonitic clay+0.2%Na ₂CO ₃+ 0.1%CMC+10% Guan Village soil

Calculate 60 according to formula 6,7,8 and change as shown in the table with plastic viscosity under the interior low-rate-of-shear rate and yield value value:

Table 760 changes plastic viscosity and the yield value with interior different rotating speeds section

Table 860 changes with the AV under the interior low-rate-of-shear rate

The above; Be merely the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, any technician who is familiar with the present technique field is in the technical scope that the present invention discloses; The variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.

Claims (3)

1. an engineering drilling fluid rheology ability method of testing is characterized in that, comprises with rotational viscosimeter the following parameter of engineering mud is tested: plastic viscosity, yield value, virtual viscosity;

μ _p=3.2 (θ ₁₀₀-θ ₆) formula 9

τ _d=0.511 * θ ₁₀₀-0.544 (θ ₁₀₀-θ ₆) formula 10

μ _e=100 θ ₃Formula 11

In the formula: μ _pBe plastic viscosity, mPas; τ _dBe yield value, Pa; μ _eBe virtual viscosity, mPas;

θ ₁₀₀, θ ₆And θ ₃Being respectively rotating speed is the reading of 100rpm, 6rpm and 3rpm rotational viscosimeter, dimensionless.

2. engineering drilling fluid rheology ability method of testing according to claim 1 is characterized in that said rotary viscosity is counted 12 fast rotational viscosimeters or continuously variable rotational viscosimeter.

3. engineering drilling fluid rheology ability method of testing according to claim 1 and 2 is characterized in that said engineering mud is petroleum drilling and used for geological prospecting mud.

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