CN104502239A - Method for measuring wettability of coal and rock - Google Patents

Method for measuring wettability of coal and rock Download PDF

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Publication number
CN104502239A
CN104502239A CN201410841172.1A CN201410841172A CN104502239A CN 104502239 A CN104502239 A CN 104502239A CN 201410841172 A CN201410841172 A CN 201410841172A CN 104502239 A CN104502239 A CN 104502239A
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China
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model
absorb water
coal petrography
silica sand
coal
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杨恒林
汪伟英
田中兰
赵梓彤
柯文丽
胡振华
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China National Petroleum Corp
Yangtze University
CNPC Engineering Technology R&D Co Ltd
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China National Petroleum Corp
Yangtze University
CNPC Drilling Research Institute Co Ltd
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Abstract

The invention provides a method for measuring the wettability of coal and rock. The method comprises the following steps: preparing a quartz sand model and a coal and rock module of coal and rock of which the wettability needs to be measured; detecting the porosity of the quartz sand model and the coal and rock module, and calculating the pore volumes of the quartz sand model and the coal and rock module; detecting the water self-absorption time and the water self-absorption volumes of the quartz sand model and the coal and rock module; respectively calculating the water self-absorption exhaust recovery efficiency and the water self-absorption zero dimension time of the quartz sand model and the coal and rock module; drawing relation curves of the water self-absorption exhaust recovery efficiency and the water self-absorption zero dimension time of the quartz sand model and the coal and rock module; calculating a ratio of the lower envelope area of the relation curve of the water self-absorption exhaust recovery efficiency and the water self-absorption zero dimension time of the coal and rock module and the lower envelop area of a standard curve, wherein the ratio serves as a self-absorption wetting index, and confirming the wettability of the wetting coal and rock to be measured. According to the technical scheme provided by the invention, the accuracy of the wettability of the coal and rock is measured, so that a reliable basis is provided for mining methane in a coal bed.

Description

Measure the method for coal petrography wetting state
Technical field
The present invention relates to coal petrography wettability determination technical field, particularly a kind of method measuring coal petrography wetting state.
Background technology
Soak and refer to liquid under the effect of interfacial tension along the phenomenon that rock surface is wandering.So-called wetting state refers to, when there is two-phase immiscible flow, wherein a certain phase fluid extends or the tendentiousness of attachment along solid surface.The wetting state of coal is the important physicochemical property of of coal, and it is the result of rock forming mineral and coal seam fluid interaction.It has a great impact the complexity of coal-seam gas micro Distribution and flowing pore media from matrix pores to the diffusion of hugger and coal-seam gas.The wetting state of Study on Coal is the important foundation of Efficient Development coal-seam gas.
The direct method of current mensuration rock wettability mainly contains wetting contact horn cupping, but require when the method is measured that mineral surface is very smooth, and the running time is oversize, mineral used are the principal ingredient of coal petrography, not actual coal petrography, measurement result directly can not represent the moisten contact angle in coal seam; Measure the indirect method mainly imbibition displacement method of wetting state, but due to Permeability Oe Coal And Porous Rock And Fractured Rock spy low, row drives volume and not easily surveys standard, and the method is mainly used in conventional sandstone and measures.In CBM Drilling and coal-bed-gas production-increase work progress, the adjuvant such as surfactant, flocculating agent is generally had in drilling fluid and stimulation fluids, after these adjuvants contact with coal seam, change making the wetting state of coal petrography, therefore, the wetting state of Measurement accuracy coal petrography is of great significance the conceptual design tool improving Coalbed Methane Productivity.
Summary of the invention
Embodiments provide a kind of method measuring coal petrography wetting state, in order to the wetting state of Measurement accuracy coal petrography, the method comprises:
Prepare the coal petrography model of silica sand model and wetting state coal petrography to be measured; Using the ability of water-wet silica sand model as standard capability;
Adopt factor of porosity detector, detect the factor of porosity of silica sand model and coal petrography model, calculate the volume of voids of silica sand model and coal petrography model;
Utilize self-priming surveying instrument, detect Absorb Water time and the Absorb Water volume of silica sand model and coal petrography model; According to Absorb Water time of silica sand model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model; According to Absorb Water time of coal petrography model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model;
According to Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model, the relation curve of the Absorb Water exhaust recovery ratio and Absorb Water non dimensional time of drawing silica sand model is as typical curve; According to Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model, draw the Absorb Water exhaust recovery ratio of coal petrography model and the relation curve curve as a comparison of Absorb Water non dimensional time; The lower envelope calculating correlation curve amasss the ratio long-pending with the lower envelope of typical curve, as self-priming wetting index;
According to self-priming wetting index, determine the wetting state of wetting state coal petrography to be measured; Self-priming wetting index equals 1, shows that the wetting ability of water to wetting state coal petrography to be measured reaches standard capability, water complete wetting wetting state coal petrography to be measured; Self-priming wetting index equals zero, and shows that water can not soak wetting state coal petrography to be measured completely, gas complete wetting wetting state coal petrography to be measured; Self-priming wetting index, more close to 0, shows that the aerophily of wetting state coal petrography to be measured is stronger; Self-priming wetting index, more close to 1, shows that the water wettability of wetting state coal petrography to be measured is stronger.
In one embodiment, in said method, according to Absorb Water time of silica sand model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model, comprising:
According to Absorb Water time and the Absorb Water volume of silica sand model, calculate the self-priming speed of silica sand model;
According to Absorb Water volume and the volume of voids of silica sand model, calculate the Absorb Water exhaust recovery ratio of silica sand model;
The self-priming speed of drafting silica sand model and Absorb Water are vented the relation curve of recovery ratio inverse, obtain slope and intercept that the self-priming speed of silica sand model and Absorb Water are vented the relation curve of recovery ratio inverse, according to Absorb Water time and the volume of voids of slope, intercept, silica sand model, calculate the Absorb Water non dimensional time of silica sand model.
In one embodiment, in said method, according to Absorb Water time of coal petrography model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model, comprising:
According to Absorb Water time and the Absorb Water volume of coal petrography model, calculate the self-priming speed of coal petrography model;
According to Absorb Water volume and the volume of voids of coal petrography model, calculate the Absorb Water exhaust recovery ratio of coal petrography model;
The self-priming speed of drafting coal petrography model and Absorb Water are vented the relation curve of recovery ratio inverse, obtain slope and intercept that the self-priming speed of coal petrography model and Absorb Water are vented the relation curve of recovery ratio inverse, according to Absorb Water time and the volume of voids of slope, intercept, coal petrography model, calculate the Absorb Water non dimensional time of coal petrography model.
In one embodiment, in said method, the Absorb Water non dimensional time according to following formulae discovery silica sand model or coal petrography model:
t D = b 2 aV p t ;
Wherein, t dfor the Absorb Water non dimensional time of silica sand model or coal petrography model, a is the slope that silica sand model or coal petrography model self-priming speed and Absorb Water are vented the relation curve of recovery ratio inverse; B is relation curve cathetus and the horizontal ordinate intersection point that silica sand model or coal petrography model self-priming speed and Absorb Water are vented recovery ratio inverse; V pfor the volume of voids of silica sand model or coal petrography model; T is the Absorb Water time of silica sand model or coal petrography model.
In one embodiment, in said method, the coal petrography model preparing silica sand model and wetting state coal petrography to be measured comprises:
Choose silica sand and be filled to also compacting in a back-up sand cylinder, the end face screen cloth of described back-up sand cylinder is sealed, forms silica sand model;
The coal petrography that will measure wetting state is ground into coal dust, takes described coal dust and is filled to also compacting in another back-up sand cylinder, and sealed by the end face screen cloth of described back-up sand cylinder, form coal petrography model.
In one embodiment, the self-priming surveying instrument in said method comprises: constant temperature oven; Electronic balance, is fixed on the top of constant temperature oven; Experiment beaker, is arranged on the inside of constant temperature oven; Computer, is connected with electronic balance; Silica sand model or coal petrography model are suspended on the lower end of electronic balance;
When measuring beginning, silica sand model or coal petrography model are put into the water of experiment beaker, open electronic balance, by the weight of the computer collection that is connected with electronic balance not silica sand model or coal petrography model in the same time, until weight is constant, obtain Absorb Water time and the Absorb Water volume of silica sand model and coal petrography model.
In one embodiment, harvester is computer, is connected with electronic balance.
In one embodiment, the experiment beaker in self-priming surveying instrument is arranged with the crane for adjusting beaker height.
In one embodiment, in said method, factor of porosity detector is helium factor of porosity detector.
Technical solution of the present invention, by preparing the coal petrography model of silica sand model and wetting state coal petrography to be measured, using the ability of water-wet silica sand model as standard capability, the relation curve of the Absorb Water exhaust recovery ratio and Absorb Water non dimensional time of drawing silica sand model is as typical curve, draw the Absorb Water exhaust recovery ratio of coal petrography model and the relation curve curve as a comparison of Absorb Water non dimensional time, the lower envelope calculating correlation curve amasss the ratio long-pending with the lower envelope of typical curve, as self-priming wetting index, according to self-priming wetting index, determine the wetting state of wetting state coal petrography to be measured, self-priming wetting index equals 1, show that the wetting ability of water to wetting state coal petrography to be measured reaches standard capability, water complete wetting wetting state coal petrography to be measured, self-priming wetting index equals zero, and shows that water can not soak wetting state coal petrography to be measured completely, gas complete wetting wetting state coal petrography to be measured, self-priming wetting index, more close to 0, shows that the aerophily of wetting state coal petrography to be measured is stronger, self-priming wetting index, more close to 1, shows that the water wettability of wetting state coal petrography to be measured is stronger.To sum up, technical scheme provided by the invention can the wetting state of Measurement accuracy coal petrography, thus provides reliable foundation for coal-bed gas exploitation.
Accompanying drawing explanation
Accompanying drawing described herein is used to provide a further understanding of the present invention, forms a application's part, does not form limitation of the invention.In the accompanying drawings:
Fig. 1 is the schematic flow sheet of the self-priming control methods measuring coal petrography wetting state in the embodiment of the present invention;
Fig. 2 is the structural representation of self-priming surveying instrument in the embodiment of the present invention;
Fig. 3 is the relation curve schematic diagram that the self-priming speed of 9 silica sand models in the embodiment of the present invention and Absorb Water are vented recovery ratio inverse;
Fig. 4 is the typical curve schematic diagram of silica sand model in the embodiment of the present invention;
Fig. 5 is the Absorb Water exhaust recovery ratio of coal petrography model in the embodiment of the present invention and the comparing result schematic diagram of the relation curve of Absorb Water non dimensional time and the typical curve of silica sand model;
Reference numeral: 1, constant temperature oven; 2, electronic balance; 3, suspension wire, 4, silica sand model or coal petrography model; 5, crane; 6, beaker is tested; 7, data line; 8, computer.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with embodiment and accompanying drawing, the present invention is described in further details.At this, exemplary embodiment of the present invention and illustrating for explaining the present invention, but not as a limitation of the invention.
Fig. 1 is the schematic flow sheet of the self-priming control methods measuring coal petrography wetting state in the embodiment of the present invention, and as shown in Figure 1, the method comprises the steps:
Step 101: the coal petrography model preparing silica sand model and wetting state coal petrography to be measured; Using the ability of water-wet silica sand model as standard capability;
Step 102: adopt factor of porosity detector, detects the factor of porosity of silica sand model and coal petrography model, and calculates the volume of voids of silica sand model and coal petrography model;
Step 103: utilize self-priming surveying instrument, detects Absorb Water time and the Absorb Water volume of silica sand model and coal petrography model; According to Absorb Water time of silica sand model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model; According to Absorb Water time of coal petrography model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model;
Step 104: according to Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model, the relation curve of the Absorb Water exhaust recovery ratio and Absorb Water non dimensional time of drawing silica sand model is as typical curve; According to Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model, draw the Absorb Water exhaust recovery ratio of coal petrography model and the relation curve curve as a comparison of Absorb Water non dimensional time; The lower envelope calculating correlation curve amasss the ratio long-pending with the lower envelope of typical curve, as self-priming wetting index;
Step 105: according to self-priming wetting index, determines the wetting state of wetting state coal petrography to be measured; Self-priming wetting index equals 1, shows that the wetting ability of water to wetting state coal petrography to be measured reaches standard capability, water complete wetting wetting state coal petrography to be measured; Self-priming wetting index equals zero, and shows that water can not soak wetting state coal petrography to be measured completely, gas complete wetting wetting state coal petrography to be measured; Self-priming wetting index, more close to 0, shows that the aerophily of wetting state coal petrography to be measured is stronger; Self-priming wetting index, more close to 1, shows that the water wettability of wetting state coal petrography to be measured is stronger.
The self-priming control methods of the mensuration coal petrography wetting state that the embodiment of the present invention provides is the experimental technique that a kind of relation curve directly utilizing coal petrography Absorb Water to be vented recovery ratio and zero dimension self-priming time judges coal petrography wetting state.The party's ratio juris is: with the ability of water-wet rock surface in quartzose sandstone-water-gas system, for standard capability, (ability of water-wet quartzose sandstone will soak the ability of quartzose sandstone much larger than gas, therefore, water and air is compared, water can soak quartzose sandstone, and air can not soak quartzose sandstone), the ability of water-wet coal petrography in coal petrography-water-gas system and above-mentioned standard capability are compared, thus judges that in coal petrography-water-gas system, water is to the wetting state of coal petrography.Specific practice is, the relation curve of recovery ratio curve and zero dimension self-priming time is vented as typical curve using the Absorb Water measured by silica sand filling compacting rock core, under coal dust filling compacting rock core Absorb Water being vented the relation curve of recovery ratio curve and zero dimension self-priming time, envelope amasss contrast long-pending with the lower envelope of described typical curve, and the ratio of two areas is as self-priming wetting index WR.As WR=1, to show in coal petrography-water-gas system that the wetting ability of water to coal petrography to reach in quartzose sandstone-water-gas system water to the wetting ability of rock, i.e. water complete wetting coal petrography.If WR=0, then show that water can not soak coal petrography completely, gas complete wetting coal petrography.When WR value is between 0 and 1, WR is more close to 0, and show that coal petrography aerophily is stronger, WR is more close to 1, then the hydrophilic ability of coal petrography is stronger.In sum, the wetting state of technical scheme energy Accurate Determining coal petrography provided by the invention.
During concrete enforcement, in a step 101, the preparation of laboratory sample: the silica sand choosing certain diameter is filled to also compacting in metal back-up sand cylinder, and back-up sand cylinder end face screen cloth seals in case sand spills, and forms silica sand model.Pulverized by the coal petrography of wetting state to be determined, cross 100 mesh sieves, take a certain amount of coal dust and be filled to also compacting in metal back-up sand cylinder, back-up sand cylinder end face screen cloth seals, and forms coal petrography model.Back-up sand cylinder diameter about 2.5cm, length 6cm.Because coal petrography pore texture and sandstone difference are very large, and frangible, so coal petrography model adopts, and the pulverizing of the coal petrography of wetting state to be determined is taken the method that a certain amount of coal dust is filled to also compacting in metal back-up sand cylinder, be beneficial to the wetting state of Accurate Determining coal petrography.
During concrete enforcement, in a step 102, sample porosity determination: adopt helium porosity measuring instrument to measure the factor of porosity of silica sand model and coal petrography model; According to the factor of porosity of silica sand model, calculate the volume of voids of silica sand model; According to the factor of porosity of coal petrography model, calculate the volume of voids of coal petrography model, particularly, (3) volume of voids of coal petrography model and silica sand model can be calculated according to the following equation.
Fig. 2 is the structural representation of self-priming surveying instrument in the embodiment of the present invention; As shown in Figure 2, the self-priming surveying instrument in step 103 comprises: constant temperature oven 1; Electronic balance 2, is fixed on the top of constant temperature oven 1; Experiment beaker 6, is arranged on the inside of constant temperature oven 1; Computer 8, is connected with electronic balance 2; Silica sand model or coal petrography model 4 are suspended on the lower end of electronic balance 2;
When measuring beginning, silica sand model or coal petrography model 4 are put into the water of experiment beaker 6, simultaneously, open electronic balance 2, the weight of not silica sand model or coal petrography model is in the same time gathered by the computer 8 be connected with electronic balance 2, until weight is constant, to obtain Absorb Water time and the Absorb Water volume of silica sand model and coal petrography model 4.
During concrete enforcement, as shown in Figure 2, electronic balance 2 is fixed on constant temperature oven 1 top, has a hook bottom electronic balance 2, after copper wire entanglement silica sand model and coal petrography model 4, is suspended on the hook of electronic balance 2 lower end; Be placed on crane 5 after experiment beaker 6 installs liquid, can by the height regulating the screw on crane 5 to regulate experiment beaker 6.When experiment starts, will silica sand model that electronic balance 2 links up with and coal petrography model 4 lower end be suspended on put into the water of experiment beaker 6.While putting into silica sand model and coal petrography model 4, open electronic balance 2, measured the weight of not silica sand model and coal petrography model 4 in the same time by the computer 8 be connected with electronic balance 2, till weight is constant, respectively silica sand model and coal petrography model are measured.
In the embodiment of the present invention, self-priming surveying instrument structure is simple, can simulate coal seam temperature, measure the surface wettability of coal petrography more really by insulation can 1.Experimental technique is simple to operate, convenient data processing.
In one embodiment, the experiment beaker 6 in self-priming surveying instrument is arranged with the crane 5 for regulation experiment beaker 6 height, and such arranging is flexible, convenient, to realize the accuracy of measuring.
During concrete enforcement, in step 103, according to Absorb Water time of silica sand model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model, comprising:
According to Absorb Water time and the Absorb Water volume of silica sand model, calculate the self-priming speed of silica sand model;
According to Absorb Water volume and the volume of voids of silica sand model, calculate the Absorb Water exhaust recovery ratio of silica sand model;
The self-priming speed of drawing silica sand model and Absorb Water are vented the relation curve of recovery ratio inverse, to obtain slope and intercept, and according to Absorb Water time of slope, intercept, silica sand model and volume of voids, and the Absorb Water non dimensional time of calculating silica sand model.
Fig. 3 is the relation curve schematic diagram that the self-priming speed of 9 silica sand models in the embodiment of the present invention and Absorb Water are vented recovery ratio inverse; Fig. 4 is the typical curve schematic diagram of silica sand model in the embodiment of the present invention; Below in conjunction with Fig. 3 and Fig. 4, for silica sand model, illustrate in step 104 process of Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time calculating silica sand model, and draw Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time typical curve of silica sand model, and the process that under calculating typical curve, envelope is long-pending:
1. as shown in Figure 3, the self-priming speed Q of water is drawn wbe vented the relation curve of recovery ratio inverse with silica sand model Absorb Water, obtain slope a and intercept b:
Any time silica sand model or the Absorb Water exhaust recovery ratio R of coal petrography model (hereinafter referred to as laboratory sample) be defined as this moment rock sample and add up to absorb water the number percent of volume and volume of voids, be namely vented recovery ratio according to the Absorb Water of following formulae discovery silica sand or coal petrography:
R = N wt V p ; - - - ( 1 )
By
? S wf = N wt V p - - - ( 4 )
In formula: x is the self-priming length of any time, cm;
N wtfor the accumulative water suction volume (Absorb Water volume) of any time, cm 3;
A is self-priming sectional area, cm 2;
V pfor laboratory sample volume of voids, cm 3;
R is Absorb Water exhaust recovery ratio, %;
for laboratory sample factor of porosity, %;
S wffor the postcostal water saturation of self-priming, %.
Self-priming speed Q wand linear formula is as follows between the inverse that Absorb Water is vented recovery ratio:
Self-priming speed Q wcomputing formula: Q w = dN wt dt = a 1 R - b - - - ( 5 )
b = Ak w μ w Δρg - - - ( 6 )
a = Ak w S wf μ w L P c - - - ( 7 )
In formula: Q wfor self-priming speed, g/min;
A is self-priming speed Q wthe slope of the relation curve of recovery ratio inverse is vented with Absorb Water;
B is self-priming speed Q wrelation curve cathetus and the horizontal ordinate intersection point of recovery ratio inverse is vented with Absorb Water.
By above-mentioned self-priming data, make Q wwith graph of relation, figure as indicated at 3, slope a and the intercept b of straight line can be obtained.
2. zero dimension self-priming time is changed into according to by the laboratory sample Absorb Water time:
Non dimensional time computing formula:
In formula: S wffor the postcostal water saturation of self-priming, %;
K wfor S wfthe effective permeability of corresponding water, 10-3 μm 2;
P cfor S wfcorresponding capillary pressure, Pa;
for laboratory sample factor of porosity, %;
μ wfor the viscosity of water, mPas;
T is self-priming time, min;
L is laboratory sample length, cm;
C is the ratio of gravity and capillary force;
L afor characteristic length, cm.
Characteristic length L in this experiment a=L.
R = N wt V p - - - ( 9 )
k w = μ w AΔρg b - - - ( 10 )
P c = 1 S wf a b Δρg L a - - - ( 11 )
By P cwith k wdefinition substitute in equation (8) and can obtain by abbreviation
t D = b 2 a V p t - - - ( 12 )
3. as shown in Figure 4, at step 104, the relation curve drawing silica sand Absorb Water exhaust recovery ratio and non dimensional time is as typical curve, and the lower envelope obtaining this typical curve amasss.And the lower envelope of the exhaust of the Absorb Water of coal petrography model recovery ratio and the relation curve of zero dimension Absorb Water time is amassed to amass with the lower envelope of typical curve and make ratio.
Lower envelope amasss ratio calculation formula: W R = W coal W s tan dard - - - ( 13 )
Wherein: W rbe defined as self-priming wetting index;
W coalfor the lower envelope of the Absorb Water exhaust recovery ratio curve of coal petrography model amasss, cm 2;
W standardfor the lower envelope of typical curve amasss, cm 2.
In step 103, according to Absorb Water time of coal petrography model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model, comprising:
According to Absorb Water time and the Absorb Water volume of coal petrography model, calculate the self-priming speed of coal petrography model;
According to Absorb Water volume and the volume of voids of coal petrography model, calculate the Absorb Water exhaust recovery ratio of coal petrography model;
The self-priming speed of drawing coal petrography model and Absorb Water are vented the relation curve of recovery ratio inverse, to obtain slope and intercept, and according to Absorb Water time of slope, intercept, coal petrography model and volume of voids, and the Absorb Water non dimensional time of calculating coal petrography model.
The above-mentioned Absorb Water time according to coal petrography model, Absorb Water volume and volume of voids, calculate the Absorb Water exhaust recovery ratio of coal petrography model and the step of Absorb Water non dimensional time, and draw the process of coal petrography model Absorb Water exhaust recovery ratio and zero dimension Absorb Water time curve, can reference: as above-mentioned for silica sand model, illustrate the process of Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time calculating silica sand model, and draw the process of silica sand model Absorb Water exhaust recovery ratio and zero dimension Absorb Water time curve, namely as 1. above-mentioned, and 3. 2. described in, no longer describe in detail at this.
During concrete enforcement, in step 103, according to the Absorb Water non dimensional time of following formulae discovery silica sand model or coal petrography model:
t D = b 2 a V p t ;
This formula is above-mentioned formula (12), concrete derivation as above-mentioned steps 1. and 2. as described in, the embodiment of the present invention introduces zero dimension self-priming time, so just can eliminate the error because laboratory sample profile variation and physical property do not cause on an equal basis, further ensure the wetting state of Accurate Determining coal petrography.
Wherein, t dfor the Absorb Water non dimensional time of silica sand model or coal petrography model, a is the slope that silica sand model or coal petrography model self-priming speed and Absorb Water are vented the relation curve of recovery ratio inverse; B is relation curve cathetus and the horizontal ordinate intersection point that silica sand model or coal petrography model self-priming speed and Absorb Water are vented recovery ratio inverse; V pfor the volume of voids of silica sand model or coal petrography model; T is the Absorb Water time of silica sand model or coal petrography model.
At step 104, typical curve is the Absorb Water exhaust recovery ratio of silica sand model and the relation curve of zero dimension self-priming time, its lower envelope amasss and reflects the wetting ability of water to silica sand rock, in like manner, the lower envelope of the Absorb Water exhaust recovery ratio of coal petrography model and the relation curve of Absorb Water non dimensional time amasss and reflects the wetting ability of water to coal petrography.
Be described with example more below, so that understand how to implement the present invention.
(1) preparation of typical curve (being Absorb Water exhaust recovery ratio and the relation curve without therefore Absorb Water time of silica sand model) and drawing process: the silica sand model making 9 pieces of strong hydrophilicities in experiment.In experimentation, electronic balance 2 is fixed on the top of constant temperature oven 1, has a hook bottom electronic balance 2, with copper wire entanglement silica sand model rear-mounted on the hook of electronic balance 2 lower end.Experiment beaker 6 is after placing water placed on crane 5, by the height regulating the screw on crane 5 to regulate experiment beaker 6.When experiment starts, the silica sand model lower end be suspended on electronic balance 2 is put into the water of beaker 6.While putting into rock core, open electronic balance 2, computer 8 measures the weight of not silica sand model in the same time, until weight is constant.Calculate the zero dimension self-priming time of each block silica sand model, as shown in Figure 3, draw zero dimension self-priming time and the Absorb Water exhaust recovery ratio curve of 9 pieces of silica sand models, the curve that 9 kinds of figures such as its intermediate cam, square frame etc. are linked to be represents No. 1 ~ 9, silica sand model respectively.Then the zero dimension self-priming time of 9 pieces of silica sand models and Absorb Water exhaust recovery ratio are averaged, draw the relation curve of average Absorb Water exhaust recovery ratio and average zero dimension self-priming time, be typical curve.
Particularly, first, the self-priming speed Q of silica sand model is drawn wand Absorb Water is vented the relation curve between the inverse of recovery ratio R, obtain slope a and intercept b, in table 2.Slope a and intercept b is substituted in the calculating formula (12) of the zero dimension self-priming time after simplifying, zero dimension self-priming time t can be tried to achieve d.Then the Absorb Water of 9 pieces of sandstone sand-packed models exhaust recovery ratio and zero dimension self-priming time are averaged, then draw and obtain typical curve, as shown in Figure 4.
(2) Absorb Water of coal petrography model is vented preparation and the drawing process of recovery ratio curve: the coal petrography choosing Feng huangshan Mountain and Si He ore deposit in the embodiment of the present invention, pulverize rear mistake 100 mesh sieve, by coal dust compacting, finally make coal petrography model, test according to the experimental technique of silica sand model above, as shown in Figure 5, under the same coordinate system, drafting coal petrography Absorb Water exhaust recovery ratio curve and typical curve contrast.
Fig. 5 is the Absorb Water exhaust recovery ratio of coal petrography model in the embodiment of the present invention and the comparing result schematic diagram of the relation curve of Absorb Water non dimensional time and the typical curve of silica sand model; Known with experimental result as shown in Figure 5: it is 114.0983 that the lower envelope of the typical curve of silica sand amasss, it is 69.6613 that the lower envelope of Feng huangshan Mountain coal petrography Absorb Water exhaust recovery ratio curve amasss, and it is 21.5453 that the lower envelope of river, temple pit coal rock Absorb Water exhaust recovery ratio curve amasss.Result as can be seen from table 5, utilizes the wetting state judging coal petrography that self-priming wetting index method can be quantitative.Can calculate the self-priming wetting index of different mining areas coal petrography according to the definition of equation (13): the WR of Feng huangshan Mountain coal petrography is 0.6105 (that is: the lower envelope of Feng huangshan Mountain coal petrography Absorb Water exhaust recovery ratio curve amasss the ratio long-pending with the lower envelope of typical curve), the WR of river, temple pit coal rock is 0.1888 (that is: the lower envelope of river, temple pit coal rock Absorb Water exhaust recovery ratio curve amasss the ratio long-pending with the lower envelope of typical curve).It can thus be appreciated that utilize the wetting state of the judgement coal petrography that the method that proposes in the present invention can be quantitative, can find out weak than Feng huangshan Mountain coal petrography of the water wettability of river, temple pit coal rock by result, Feng huangshan Mountain coal petrography is slightly water-wet, and river, temple pit coal rock is not hydrophilic.
The basic data of table 1 sandstone sand-packed model
Rock core number Length (cm) Diameter (cm) Lc(cm) Vp(cm3) Factor of porosity (%)
1 4.013 2.042 4.013 6.663 50.725
2 4.013 2.042 4.013 6.663 50.725
3 4.937 2.047 4.937 7.336 45.174
4 4.948 2.067 4.948 7.849 47.297
5 4.937 2.047 4.937 6.449 39.712
6 4.948 2.067 4.948 6.660 40.132
7 4.013 2.042 4.013 6.826 51.966
8 4.013 2.042 4.013 6.882 52.392
9 4.937 2.047 4.937 6.753 41.584
Table 2 experiment obtains slope and the intercept that self-priming speed and Absorb Water are vented recovery ratio relation curve
Rock core number a b
1 1.0755 1.2282
2 0.3275 0.3915
3 0.3817 0.5435
4 0.5903 0.7862
5 0.3545 0.4212
6 0.2745 0.3482
7 0.2617 0.3698
8 0.2888 0.3897
9 0.2683 0.3837
The basic data of table 3 coal petrography sand-packed model
Under table 4 coal petrography Absorb Water exhaust recovery ratio curve, envelope is long-pending amasss with envelope under typical curve
Table 5 self-priming pairing comparision determination experiment result
Rock core number Under self-priming curve, envelope amasss WR Wetting state
Typical curve 114.0983 1 Strong hydrophilicity
F1 69.6613 0.6062 Slightly water-wet
S1 21.5453 0.1811 Not hydrophilic
Compared with prior art, technical solution of the present invention can reach following beneficial effect:
(1) technical solution of the present invention is a kind of experimental technique directly utilizing Absorb Water recovery ratio curve to judge coal petrography wetting state, measures convenient, simple, can the wetting state of quantitative measurement coal petrography, thus provides reliable basis for coal-bed gas exploitation.Experimental apparatus structure is simple, can simulate coal seam temperature, measure the surface wettability of coal petrography more really.
(2) technical solution of the present invention considers rock impact by pore texture in self-priming process, in order to eliminate this impact, uses the mode preparation experiment sample of back-up sand in an experiment.Adopt the mode of back-up sand, the pore texture of the coal dust sand-packed model made is similar with the pore texture of quartz model, and eliminate the difference of rock core pore texture to the impact of experiment, the experimental result drawn has comparability.
(3) electronic balance is utilized to be connected with computer by data line in the experimental provision of technical solution of the present invention, computer is provided with data acquisition software, automatically can be gathered the reading on electronic balance by data acquisition software, the mode automatically gathered greatly enhances conventional efficient.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the embodiment of the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1. measure a method for coal petrography wetting state, it is characterized in that, comprising:
Prepare the coal petrography model of silica sand model and wetting state coal petrography to be measured; Using the ability of silica sand model described in water-wet as standard capability;
Adopt factor of porosity detector, detect the factor of porosity of described silica sand model and coal petrography model, calculate the volume of voids of silica sand model and coal petrography model;
Utilize self-priming surveying instrument, detect Absorb Water time and the Absorb Water volume of described silica sand model and coal petrography model; According to Absorb Water time of silica sand model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model; According to Absorb Water time of coal petrography model, Absorb Water volume and volume of voids, calculate Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model;
According to Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model, the relation curve of the Absorb Water exhaust recovery ratio and Absorb Water non dimensional time of drawing silica sand model is as typical curve; According to Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of described coal petrography model, draw the Absorb Water exhaust recovery ratio of coal petrography model and the relation curve curve as a comparison of Absorb Water non dimensional time; The lower envelope calculating described correlation curve amasss the ratio long-pending with the lower envelope of described typical curve, as self-priming wetting index;
According to described self-priming wetting index, determine the wetting state of wetting state coal petrography to be measured; Described self-priming wetting index equals 1, shows that the wetting ability of water to described wetting state coal petrography to be measured reaches described standard capability, water complete wetting wetting state coal petrography to be measured; Described self-priming wetting index equals zero, and shows that water can not soak wetting state coal petrography to be measured completely, gas complete wetting wetting state coal petrography to be measured; Described self-priming wetting index, more close to 0, shows that the aerophily of described wetting state coal petrography to be measured is stronger; Described self-priming wetting index, more close to 1, shows that the water wettability of described wetting state coal petrography to be measured is stronger.
2. the method for claim 1, is characterized in that, the described Absorb Water time according to silica sand model, Absorb Water volume and volume of voids, calculates Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of silica sand model, comprising:
According to Absorb Water time and the Absorb Water volume of silica sand model, calculate the self-priming speed of silica sand model;
According to Absorb Water volume and the volume of voids of silica sand model, calculate the Absorb Water exhaust recovery ratio of silica sand model;
The self-priming speed of drafting silica sand model and Absorb Water are vented the relation curve of recovery ratio inverse, obtain slope and intercept that the self-priming speed of described silica sand model and Absorb Water are vented the relation curve of recovery ratio inverse, according to Absorb Water time and the volume of voids of described slope, intercept, silica sand model, calculate the Absorb Water non dimensional time of silica sand model.
3. method as claimed in claim 2, is characterized in that, the described Absorb Water time according to coal petrography model, Absorb Water volume and volume of voids, calculates Absorb Water exhaust recovery ratio and the Absorb Water non dimensional time of coal petrography model, comprising:
According to Absorb Water time and the Absorb Water volume of coal petrography model, calculate the self-priming speed of described coal petrography model;
According to Absorb Water volume and the volume of voids of coal petrography model, calculate the Absorb Water exhaust recovery ratio of coal petrography model;
The self-priming speed of drafting coal petrography model and Absorb Water are vented the relation curve of recovery ratio inverse, obtain slope and intercept that the self-priming speed of described coal petrography model and Absorb Water are vented the relation curve of recovery ratio inverse, according to Absorb Water time and the volume of voids of described slope, intercept, coal petrography model, calculate the Absorb Water non dimensional time of coal petrography model.
4. method as claimed in claim 3, is characterized in that, the Absorb Water non dimensional time according to following formulae discovery silica sand model or coal petrography model:
t D = b 2 a V p t ;
Wherein, t dfor the Absorb Water non dimensional time of silica sand model or coal petrography model, a is the slope that silica sand model or coal petrography model self-priming speed and Absorb Water are vented the relation curve of recovery ratio inverse; B is relation curve cathetus and the horizontal ordinate intersection point that silica sand model or coal petrography model self-priming speed and Absorb Water are vented recovery ratio inverse; V pfor the volume of voids of silica sand model or coal petrography model; T is the Absorb Water time of silica sand model or coal petrography model.
5. the method for claim 1, is characterized in that, the described coal petrography model preparing silica sand model and wetting state coal petrography to be measured comprises:
Choose silica sand and be filled to also compacting in a back-up sand cylinder, the end face screen cloth of described back-up sand cylinder is sealed, forms silica sand model;
The coal petrography that will measure wetting state is ground into coal dust, takes described coal dust and is filled to also compacting in another back-up sand cylinder, sealed by the end face screen cloth of described back-up sand cylinder, form coal petrography model.
6. the method for claim 1, is characterized in that, described self-priming surveying instrument comprises: constant temperature oven; Electronic balance, is fixed on the top of described constant temperature oven; Experiment beaker, is arranged on the inside of described constant temperature oven; Harvester, is connected with described electronic balance; Described silica sand model or coal petrography model are suspended on the lower end of described electronic balance;
When measuring beginning, described silica sand model or coal petrography model are put into the water of described experiment beaker, open electronic balance, by the weight of the harvester collection that is connected with electronic balance not silica sand model or coal petrography model in the same time, until weight is constant, obtain Absorb Water time and the Absorb Water volume of described silica sand model and coal petrography model.
7. method as claimed in claim 6, it is characterized in that, described harvester is computer, is connected with described electronic balance.
8. method as claimed in claim 6, it is characterized in that, described experiment beaker is arranged with the crane for adjusting beaker height.
9. the method for claim 1, is characterized in that, described factor of porosity detector is helium factor of porosity detector.
CN201410841172.1A 2014-12-30 2014-12-30 Method for measuring wettability of coal and rock Pending CN104502239A (en)

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