CN102374960B - Variable-diameter-tube drilling fluid rheology measuring method - Google Patents

Abstract

The invention relates to a variable-diameter-tube drilling fluid rheology measuring method which is especially suitable for on-line detections of in situ drilling fluid rheology. The method comprises steps that: a variable-diameter-tube system is composed of 2 to 20 segments of tubules with different diameters, wherein the tubules are connected in series; a stable flow rate is provided for the variable-diameter-tube system by using a constant flow pump and a buffer; current velocities in different diameter segments of the variable-diameter-tube system are calculated according to the flow rate and the cross section areas of the tubules; velocity gradients in different diameter segments are calculated according to the current velocities and diameters of the different diameter segments of the variable-diameter-tube system; pressure losses in different diameter segments of the variable-diameter-tube system are detected by using a differential pressure gauge; shear stress values of the different diameter segments of the variable-diameter-tube system are calculated according to the pressure losses; and rheology parameters such as plastic viscosity, dynamic shearing force, flow pattern index, and consistency coefficient of the measured drilling fluid can be calculated according to the shear stress values under different velocity gradients. With the method provided by the invention, drilling fluid rheology and variation conditions thereof can be measured in real-time without changing the flow rate.

Description

A kind of variable-diameter-tube drilling fluid rheology measuring method

Technical field

The present invention relates to a kind of variable-diameter-tube drilling fluid rheology measuring method, the rheological that is particularly suitable for on-the-spot drilling fluid detects online.

Background technology

Rheology is a science of research flow of matter and distortion, and the research of drilling fluid rheology is a rheol importance.The rheological of drilling fluid generally comprises viscosity, gel strength, yield value and the shear thinning behavior etc. of fluid.The grasp of these rheologicals and adjustment have very important relation with raising bit speed and downhole safety.Drilling fluid rheology is related to the ability that (1) drilling fluid carries drilling cuttings, cleaning well; (2) suspending power; (3) to the stabilization of the borehole wall; (4) calculating of the optimal design of drilling parameter---hydraulic bit horsepower design and cyclic pressure dissipation etc.So the measurement of drilling fluid rheology and rheological research is paid attention to deeply always.

The measuring method of rheological has a variety of, the most frequently used methods that Guan Liufa, rotary process, falling ball method, disk method, vibratory drilling method etc. are arranged at present.Wherein rotary process and Guan Liufa are the common methods that drilling fluid rheology is measured.

It is present a kind of widely used method that drilling fluid viscosity is measured in rotary process.Its ultimate principle is: when fluid be dipped in wherein object one of both or when both all rotating, object will be subject to the effect of fluid viscosity moment and change original rotating speed or torque, and the rotating speed that acts on the viscosity moment of object or object by measuring fluid is determined the viscosity of fluid.The rotary process scope of application is wide, and it is convenient to measure, a large amount of data that are easy to get, but there are a lot of limitation.

The red-spotted stonecrop of Xi'an shiyou University help etc. the people as far back as 1989 just the rheological telemetering device to on-the-spot drilling fluid be studied, the cardinal principle of the telemetering device that they develop is that a torque motor drives the rotating cylinder rotation, calculates the rheological parameter according to rotational speed and moment measured value.This paper has also been proved the single-drum viscosity meter, although can measure fluid viscosity in theory, but can only measure the viscosity under low shear rate, in actual well drilled, the velocity gradient of fluid is often very high, this just requires the very wide direct current torque motor of amplitude modulation range, selects to real electrical machinery and has brought certain difficulty.

The people such as A.Saasen had adopted Couette (Ku Aite) viscosity meter that can measure viscosity under different shear rate in 2008, and this viscosity meter is the bitubular viscosity meter of controlling rotating speed.There is the replacement problem of drilling fluid between interior outer barrel in the double-cylinder type rotational viscosimeter.So will come the continuous coverage drilling fluid rheology also to exist a lot of problems to need to solve with rotary process, be difficult to realize present drilling fluid rheology on-line measurement.

Guan Liufa is also a kind of common method of rheological measurement, and the principle of this method is hage oiseuillelaw, and namely the liquid of certain volume is proportional to the viscosity of laminar flow by given kapillary required time under the certain pressure gradient.Therefore, get final product to get liquid viscosity by measuring flow rate of liquid and the liquid pressure differential that kapillary produces of flowing through.The capillary viscosimeter manufacturing is simple, and price is lower, and temperature is controlled simple, and convenient experimental operation can be carried out the absolute measurement of viscosity, so capillary tube technique is a kind of attractive measuring method.

1991, patent CN2085960 once proposed the rheological that a kind of capillary rheometer be used for to be measured drilling fluid, it is characterized in that: the differential pressure measurement system is comprised of slit kapillary and a pressure transducer that is arranged on this kapillary wall.But this instrument can only change different flow ability conversion rate gradient and pressure loss, can not realize simultaneously the measurement of friction speed gradient down cut stress, therefore can not be from realizing in essence the continuous coverage of rheological.

2002, the capillary viscosimeter that patent G01N11/06 proposes, this capillary viscosimeter is mainly used to measure kinematic viscosity.

In a word, existing capillary viscosimeter can only be realized the measurement of the apparent viscosity under single flow velocity, if measure the rheological under the friction speed gradient, just needs variable flow, therefore can not the instantaneous rheological of continuous coverage non-Newtonian fluid.And traditional capillary viscosimeter is easily stopped up by small particle.

Current, along with the raising of petroleum drilling engineering automaticity, the automatically-monitored technology of property of drilling fluid more and more comes into one's own, and is particularly more urgent to the demand of drilling fluid rheology line Measurement Technique.Realize drilling fluid rheology automatic online measuring technique, its key is the method for METHOD FOR CONTINUOUS DETERMINATION drilling fluid rheology and variation thereof.Present conventional drilling fluid rheology method of testing is no matter be that rotary process or capillary tube technique all can not satisfy the needs of continuous coverage drilling fluid rheology.Because conventional capillary tube technique can only be measured the apparent viscosity under single velocity gradient, perhaps must successively change flowing velocity and realize rheological measurement, measure a cover rheological curve needs the time longer, so the variation of drilling fluid rheology is difficult to measure rapidly; And there is the displacement efficiency problem of drilling fluid between inner/outer tube when measuring rheological in rotary process; Therefore, existing rheological measurement method is difficult to realize the drilling fluid rheology continuous coverage, in order to overcome defects, the invention provides a kind of variable-diameter-tube drilling fluid rheology measuring method.

The present invention compared with prior art has following advantage: easy and simple to handle, can realize the rheological continuous coverage of drilling fluid.

Summary of the invention

Existing rheological measurement method is difficult to realize the drilling fluid rheology continuous coverage, because conventional capillary tube technique can only be measured the apparent viscosity under single express delivery gradient, perhaps must successively change flowing velocity and realize rheological measurement, measuring a cover rheological curve needs the time longer, so the variation of drilling fluid rheology is difficult to measure rapidly; And there is the displacement efficiency problem of drilling fluid between inner/outer tube when measuring rheological in rotary process.In order to overcome the deficiency of normal flow sex change measuring method, patent of the present invention provides a kind of reducing capillary pipe method of testing.

The technical scheme that the disclosed method of this patent adopts is: utilize the tubule of 2～20 sections different-diameters to form reducer pipe, in the situation that flow is identical, at the different flow velocity of pipeline section generation of different-diameter; Then calculate the velocity gradient of different-diameter pipeline section according to the physical dimension of flow velocity and tubule; Measure different-diameter pipeline section pressure reduction by differential manometer, calculate the shear stress of different-diameter pipeline section according to tubule physical dimension and pressure loss; Calculate at last the rheological parameter of tested drilling fluid according to the shear stress under the friction speed gradient.

Advantage of the present invention is: this method of testing fundamentally changes existing drilling fluid rheology measurement pattern, can realize the rheological characteristics of continuous coverage fluid, this invention is conducive to realize the on-line measurement of drilling fluid rheology parameter, improved the isoparametric measurement efficient of drilling fluid rheology, significant to On-line Control and the adjusting of property of drilling fluid in the drilling well production run.

Description of drawings

Fig. 1 is variable-diameter-tube drilling fluid rheology measuring method general flow chart according to an embodiment of the present invention;

Fig. 2 is the structural representation of the constructed reducer pipe system of method step 102 shown in Figure 1;

Fig. 3 is the structural drawing of the constructed reducer pipe system of first embodiment;

Fig. 4 is the measurement result of first embodiment---the rheological curve schematic diagram;

Fig. 5 is second embodiment, the structural drawing of constructed reducer pipe system;

Fig. 6 is a measurement result---the rheological curve schematic diagram of second embodiment.

Embodiment

Below in conjunction with accompanying drawing, embodiments of the present invention are described in detail.

Fig. 1 is the variable-diameter-tube drilling fluid rheology measuring method general flow chart according to an embodiment of the present invention, and this flow process starts from step 101.Then, in step 102, build the reducer pipe system.

Fig. 2 shows the structure composition of reducer pipe system, and in Fig. 2, reducer pipe (205) is to be in series by 2～20 tubules that save different-diameters, and the tubule of different-diameter is connected with taper joint.The reducer pipe system is comprised of constant flow pump (201), impact damper 202, flowmeter 203, differential manometer group 204 and reducer pipe 205.Constant flow pump, impact damper, flowmeter and reducer pipe are connected successively, and each differential manometer in the differential manometer group is connected on respectively on two pressure taps of each pipe joint of reducer pipe.In order to reduce the end side effect of pipe stream, pressure tap should leave and respectively save the above distance of 10 times of calibers of tubule end points.

Step 103 in Fig. 1 is united realization by constant flow pump 201 and impact damper 202.Constant flow pump 201 can be the above ram pump of two cylinders, screw pump, centrifugal pump etc.; Impact damper can have certain flexible container and form, and is exciting with the pressure that reduces pump, in order to offer the just more stable flow of footpath guard system.

Step 104 in Fig. 1 is the moment with timer record test rheological.

Step 105 in Fig. 1 is with the intrasystem volumetric flow rate q of flowmeter Measurement accuracy reducer pipe.

Step 106 in Fig. 1 is with the pressure differential Δ p between two pressure taps on a plurality of manometry different-diameter pipeline sections _m(m=1,2 ..., 20; Wherein m is the tubule joint number of reducer pipe), the perhaps pressure loss on the different-diameter pipeline section of certain-length.The differential manometer of measuring pressure reduction also can adopt two a pair of power table or a pair of pressure transducers.

Step 107 in Fig. 1 is to calculate the velocity gradient γ of different pipe sections with the diameter of flow q and different pipe sections _m(m=1,2 ..., 20 wherein m be the tubule joint number of reducer pipe).

Step 108 in Fig. 1, be according in each pipeline section pipe along stroke pressure loss Δ p _mCalculate each pipeline section fluid to the shear force of tube wall with the cross-sectional area of each pipeline section, then shear force and the tube wall lateral area according to tube wall calculates each pipeline section shearing stress value.

Step 109 in Fig. 1, be according to the shear stress values under several (m) velocity gradients, on shearing stress one velocity gradient coordinate, Bingham model and power law method carried out curve fitting, obtain correlation coefficient, judge according to correlation coefficient drilling fluid is closer to which kind of flow pattern.

Step 110 in Fig. 1 is if meet Bingham model, calculates plastic viscosity and yield value.

Step 111 in Fig. 1 is if flow pattern closer to power-law fluid, calculates flow pattern exponential sum consistency index.

Step 107 in Fig. 1～111 also can change into: after the pressure loss of measuring flow q and different tube diameters section, geometric parameter and pressure loss according to reducing capillary pipe different-diameter pipeline section, press the interior flowing pressure loss equation of pipe of Bingham fluid and the interior flowing pressure loss equation of pipe of power-law fluid, obtain the optimum solution of plastic viscosity, yield value, liquidity index and consistency index with least square method.

Step 112 in Fig. 1 is that rheological parameter constantly measured in record.

113 steps in Fig. 1 are to set as required next time the moment of measuring, between time at intervals changeable, can Timing measurement, also can arbitrarily measure.

Step 114 in Fig. 1 is according to the needs of measuring, and decision-making is a step that continues to measure or finish measurement.

Flow process ends at step 115.

Although described by reference to the accompanying drawings embodiments of the present invention, those of ordinary skills can make various changes and modifications within the scope of the appended claims.

Embodiment 1: in the embodiments of figure 3, with constant flow pump (301) and damper (302) combination, provide the flow of no pulse, and with the flow q of flowmeter (303) Accurate Determining fluid; With radius difference r ₁And r ₂Two joint kapillaries (306 and 307) series connection, form reducer pipe, to realize different flowing velocity v _m(m=1,2); Flowing velocity v according to each joint reducer pipe _mCalculate the two velocity gradient γ that save on the reducing tube walls with the diameter of each joint reducer pipe ₁And γ ₂Measure respectively first segment and second section reducer pipe at Δ L with differential manometer (304 and 305) ₁With Δ L ₂Pressure loss Δ p in tube side ₁With Δ p ₂, according to the radius r of two joint reducer pipes ₁And r ₂, length Δ L ₁With Δ L ₂, and pressure loss Δ p ₁With Δ p ₂Calculate the shear stress values τ on the 2-section pipe wall ₁And τ ₂According to friction speed gradient γ ₁And γ ₂The time shear stress values τ ₁And τ ₂, calculate apparent viscosities il _a, plastic viscosity η _p, yield value τ ₀, liquidity index n and consistency index K.The rheological test result of first embodiment is seen Fig. 3.

Embodiment 2: in the embodiment of Fig. 5, with constant flow pump (501) and damper (502) combination, provide the flow of no pulse, and with the flow q of flowmeter (503) Accurate Determining fluid; With radius difference r ₁, r ₂, r ₃, r ₄, r ₅, r ₆Six joint kapillaries (516,517,518,519,520,521) form reducer pipes, to realize different flowing velocity v _n(n=1,2,3,4,5,6) and velocity gradient γ ₁, γ ₂, γ ₃, γ ₄, γ ₅, γ ₆Measure the interior Δ L of first segment kapillary with pressure gauge (504 and 505) ₁Pressure loss Δ p in tube side ₁, measure second section Δ L capillaceous with pressure gauge (506 and 507) ₂Pressure loss Δ p in tube side ₂, measure Δ L in the 3rd joint kapillary with pressure gauge (508 and 509) ₃Pressure loss Δ p in tube side ₃, measure the 4th inherent Δ L of joint kapillary with pressure gauge (510 and 511) ₄Pressure loss Δ p in tube side ₄, measure the 5th inherent Δ L of joint kapillary with pressure gauge (512 and 513) ₅Pressure loss Δ p in tube side ₅, measure Δ L in the 6th joint kapillary with pressure gauge (514 and 515) ₆Pressure loss Δ p in tube side ₆Set up the inconsistent equation group according to flowing pressure loss formula (equation 1) in the Bingham fluid pipe, solve plastic viscosity (μ _p) and yield value (τ ₀); Set up the inconsistent equation group according to flowing pressure loss formula (equation 2) in transfer of power law fluid flowing in tube, solve liquidity index (n) and consistency index (k).The rheological test result of second embodiment as shown in Figure 6.

$\mathrm{\Δ}{p}_n=\frac{128\mathrm{\Δ}{L}_{n}q{\mathrm{\μ}}_P}{\mathrm{\π}{D_n}^4}+\frac{4{\mathrm{\τ}}_0\mathrm{\Δ}{L}_n}{D_n}$ Equation 1

$\mathrm{\Δ}{p}_n=\frac{4\mathrm{k\Δ}{L}_n}{D_n}{\left(\frac{q}{\mathrm{\π}{D_n}^3}\frac{24n+8}{n}\right)}^n$ Equation 2

Claims (1)

1. a variable-diameter-tube drilling fluid rheology measuring method, belong to fluid-guiding type rheological measurement method, it is characterized in that comprising the following steps:

Step 1. beginning;

Step 2. structure reducer pipe system: reducer pipe is to be in series by 2～20 tubules that save different-diameters, the tubule of different-diameter is connected by taper joint, the reducer pipe system is comprised of constant flow pump, impact damper, flowmeter, differential manometer group and reducer pipe, constant flow pump, impact damper, flowmeter and reducer pipe are connected successively, each differential manometer in the differential manometer group is connected on respectively on two pressure taps of each pipe joint of reducer pipe, in order to reduce the end side effect of pipe stream, pressure tap leaves the above distance of 10 times of calibers of each pipe joint end points, and pressure tap is on tube wall;

Step 3. provides stable mud flow rate: unite realization by constant flow pump and impact damper;

T constantly measured in step 4. record: measure t constantly with timer record;

Step 5. is measured the flow of t constantly: with the intrasystem volumetric flow rate of flowmeter survey reducer pipe;

Step 6. is measured each section pressure loss of t constantly: measure the pressure loss of each section of t pipe constantly with many group differential manometers;

Step 7. is calculated the velocity gradient of t different pipe sections constantly: the velocity gradient of calculating different pipe sections with the diameter of flow and different pipe sections;

Step 8. is calculated the shearing stress value of t different pipe sections constantly: calculate each pipeline section fluid to the shear force of tube wall according to the pressure loss of each pipeline section and the cross-sectional area of each pipeline section, then shear force and the tube wall lateral area according to tube wall calculates each pipeline section shearing stress value;

Step 9. judgement flow pattern: the shearing stress value according under the friction speed gradient, reheology model is carried out curve fitting, obtain correlation coefficient, the judgement drilling fluid is closer to which kind of flow pattern;

Step 10. Flow variable element: according to the flow pattern of step 9 judgement, if meet Bingham model, calculate plastic viscosity and the moving shearing stress value of t constantly; If meet power law method, calculate consistency index and the flow pattern index of t constantly;

Step 11. record is the various rheological parameters of t constantly;

Constantly a rheological parameter is measured and recorded to step 12. repeating step 4～11;

Step 13. determines whether to finish experiment as required;

Step 14. finishes to measure.

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