CN102252948B - Method for measuring porosity of mud shale - Google Patents

Abstract

The invention provides a method for measuring the porosity of mud shale. The method provided by the invention comprises the following steps: selecting a whole mud shale sample block to be detected; measuring the mass M0; measuring the total volume V0 of the block; computing the block density rhob of the mud shale; rhob=M0/V0, grinding the sample; weighing a certain quantity M1 of the ground sample, wherein the M1 is less than or equal to the M0; distilling and extracting the weighed sample until the water yield is maintained to be stable; recording the volume Vw of the extracted water; taking out the distilled and extracted sample; drying until the mass is stable; recording the mass M2 of the sample; taking out the dried sample; measuring the volume Vg of particles; and computing the porosity phi of the sample, phi=(Vb-Vg)/Vg *100%, wherein Vb=M1/rhob, the method provided by the invention can avoid inconvenience in drilling out the core of mud shale, eliminate the absorption of organic matters on measurement gases, avoid organic matters from blocking a pore throat, can measure non-communication pores before the mud shale is ground and can simultaneously determine the water saturation, oil saturation and gas saturation of the mud shale.

Description

Method for measuring porosity of mud shale

Technical field

The invention relates to a kind of method for measuring porosity of mud shale, specifically refer to a kind of method that is applicable to oil, geology, mining industry field and carries out in laboratory measuring porosity of mud shale.

Background technology

At present, be not specifically designed to the method for measuring mud shale factor of porosity.

And if employing conventional sandstone porosity determination method is applied to the mensuration to mud shale factor of porosity, have very large limitation.Major embodiment is in the following areas: mud shale is easily broken, and rock core is difficult for drilling through, and rock core drill is obtained mud shale CLAY MINERALS AND THEIR SIGNIFICANCE in process and can be expanded, and working sample is limited to and affects measuring accuracy; In mud shale, there are a large amount of organic matters, can cause absorption to test gas, affect measuring accuracy; Organic existence in mud shale can be stopped up pore constriction, causes measured value less than normal; In mud shale, non-open pore is difficult for determinedly, causes measured value less than normal.

Summary of the invention

Fundamental purpose of the present invention is to overcome available technology adopting sandstone porosity assay method carries out the shortcoming of measuring porosity of mud shale, provides a kind of method for measuring porosity of mud shale for mud shale.

For reaching above-mentioned purpose, the invention provides a kind of method for measuring porosity of mud shale, the method comprises:

Step (1): choose monoblock mud shale testing sample, quality measurement M _o, measure block cumulative volume V _o, the block density ρ of calculating mud shale _b(unit, %),

Step (2): sample is pulverized, got a certain amount of M ₁, M ₁≤ M _o;

Step (3): the sample of taking-up is distilled to extracting, until water production rate keeps stable;

Step (4): by taking out through the sample of distillation extracting, be dried to steady quality;

Step (5): dried sample is taken out, measure particle volume V _g;

Step (6): calculation sample factor of porosity Φ (unit, %), $\mathrm{\&Phi;}=\frac{(V_b-V_g)}{V_b}\&times;100,$ Wherein, $V_b=\frac{{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000067501430000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_1}{{\mathrm{\&rho;}}_b}.$

Method for measuring porosity of mud shale provided by the present invention, wherein, has adopted sample has been carried out to broken mode, has avoided mud shale to drill through the inconvenience of rock core; Sample can be measured the non-open pore before pulverizing in mud shale after pulverizing; And, the present invention distilled extracting to sample before measuring factor of porosity, eliminate the organic impact on measured value, thereby make measured value more approach actual conditions, thereby method of the present invention is more suitable for oil, geology, mining industry field carries out measuring porosity of mud shale in laboratory, contribute to, to shale gas RESERVE EVALUATION, can serve shale gas exploratory development.

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, the monoblock mud shale testing sample of choosing in described step (1), its mass M _obe more than or equal to 100g.

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, in described step (1), be to adopt Archimedes's (buoyancy) mercury immersion method, mercury displacement process, kind of calliper method or with fluid but not Archimedes's method (buoyancy) of mercury is measured cumulative volume method mensuration block cumulative volume V _o.

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, in described step (2), sample is crushed to granularity and is less than or equal to the minimum non-open pore of sample.

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, described step is crushed to 12 orders or thinner by sample in (2).

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, in described step (3), be to use Dean-Stark extraction plant to distill extracting to the sample taking out.In this step (3), can extracting fuel-displaced and water, can measure respectively the fuel-displaced density p of extracting _o, water density p _wand the volume V of extracting water outlet _w(can measure according to conventional method).

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, in described step (4), be by through distillation extracting sample at 110 ℃ of freeze-day with constant temperature to steady quality.

According to specific embodiment of the invention scheme, in method for measuring porosity of mud shale of the present invention, in described step (5), be to adopt the two chambers of Boyle law method to measure the particle volume V of dried sample _g.

According to specific embodiment of the invention scheme, utilize method of the present invention, in measuring factor of porosity, can also determine water saturation, oil saturation and the gas saturation of mud shale.Method for measuring porosity of mud shale of the present invention, also can comprise the water saturation S that calculates mud shale according to following formula _w, oil saturation S _oand/or gas saturation S _gprocess (wherein, S _w, S _o, S _gunit be %):

$S_w=\frac{V_w}{(V_b-V_g)}\&times;100,$ Wherein, V _wfor the volume of extracting water outlet in step (3);

$S_o=\frac{(M_1-M_2-V_w{\mathrm{\&rho;}}_w)}{(V_b-V_g){\mathrm{\&rho;}}_o}\&times;100,$ Wherein, M ₂for dried sample quality in step (4), ρ _ofor the fuel-displaced density of extracting in step (3), ρ _wfor the density (ρ of extracting water outlet in step (3) _o, ρ _wcan measure according to conventional method);

S _g＝100-S _w-S _o。

Utilize method of the present invention to carry out measuring porosity of mud shale, there is following beneficial effect:

Sampling of the present invention and the mode that sample is processed, can avoid drilling through the restriction of rock core, the impact of the expansion factor that also having eliminated adds water drills through rock core mud shale CLAY MINERALS AND THEIR SIGNIFICANCE on measurement result; Can measure the non-open pore in mud shale simultaneously; In the present invention before measuring mud shale factor of porosity by sample is distilled to extracting, can eliminate the organic suction-operated to measurement gas, also avoided organic obstruction pore constriction; Utilize method of the present invention, in measuring mud shale factor of porosity, can also determine water saturation, oil saturation and the gas saturation of mud shale simultaneously.

Method of the present invention, is applicable to oil, geology, mining industry field and carries out measuring porosity of mud shale in laboratory, contributes to, to shale gas RESERVE EVALUATION, can serve shale gas exploratory development.

Accompanying drawing explanation

Fig. 1 shows the comparing result that adopts conventional method core analysis and adopt the inventive method lacunarity analysis.

Embodiment

Further describe feature and the result of use of method of the present invention below by specific embodiment, but the present invention is not therefore subject to any restriction.

Embodiment 1

Carry out measuring porosity of mud shale according to following operation steps:

Step (1): choose a certain amount of monoblock testing sample, quality measurement M _o(200g), measure block cumulative volume V _o(89.69cm ³) (use comprises Archimedes's (buoyancy) mercury immersion method, mercury displacement process, kind of calliper method, uses fluid but not Archimedes's method (buoyancy) mensuration cumulative volume of mercury).Calculate the block density ρ of mud shale by formula (1) _b(2.23g/cm ³).

Step (2): sample was crushed to 12 mesh sieves, gets a certain amount of M ₁(100g).

Step (3): the sample of taking-up is distilled to extracting (using Dean-Stark extraction plant), take solvent toluene, until water production rate keeps stable, record the volume V of extracting water outlet _w(0.17cm ³).

Step (4): will take out through the sample of distillation extracting, 110 ℃ of constant temperature are dried.Until sample quality is stable.Record sample quality M ₂(99.50g).

Step (5): dried sample is taken out, measure particle volume V by the two chambers of Boyle law method _g(40.87cm ³).

By formula (2), (3) calculation sample factor of porosity (V _b: 44.84cm ³; Φ: 8.86%).

By formula (4), formula (5) (in formula, ρ _w: 1.00g/cm ³; ρ _o: 0.82g/cm ³), formula (6) can calculate respectively the water saturation S of mud shale _w(4.20%), oil saturation S _oand gas saturation S (2.86%) _g(1.80%).

Formula explanation:

${\mathrm{\&rho;}}_b=\frac{M_O}{V_O}................\left(1\right)$

$\mathrm{\&Phi;}=\frac{(V_b-V_g)}{V_b}\&times;100........\left(2\right)$

$V_b=\frac{{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000067501430000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_1}{{\mathrm{\&rho;}}_b}...............\left(3\right)$

$S_w=\frac{V_w}{(V_b-V_g)}\&times;100.......\left(4\right)$

$S_o=\frac{(M_1-M_2-V_w{\mathrm{\&rho;}}_w)}{(V_b-V_g){\mathrm{\&rho;}}_o}\&times;100....\left(5\right)$

S _g＝100-S _w-S _o..........(6)

Symbol description:

Φ: factor of porosity, %

M _o: alleged complete block mud shale sample quality in step (1), g

M ₁: in step (2), get and measure mud shale sample quality, g

M ₂: distillation extracting in step (4), dry rear mud shale sample quality, g

ρ _b: the mud shale sample blocks volume density calculating in step (1), g/cm ³

ρ _o: the fuel-displaced density of extracting in step (3), g/cm ³

ρ _w: the density of extracting water outlet in step (3), g/cm ³

V _o: the complete block mud shale sample volume of surveying in step (1), cm ³

V _b: the pulverizing mud shale sample block volume calculating in step (2), cm ³

V _g: the dry sample particle volume of measuring in step (5), cm ³

V _w: the volume of extracting water outlet in step (3), cm ³

S _w: water saturation, %

S _o: oil saturation, %

S _g: gas saturation, %

According to the method for above-described embodiment 1, respectively five groups of mud shale samples (are got to three parallel sample for every group, average) carry out porosity determination, and adopt conventional method (measuring according to Boyle-Marriot law principle design) core analysis to carry out porosity determination to the Duplicate Samples of every group of mud shale sample, carrying out porosity determination result with employing method of the present invention analyzes relatively, determination data refers to table 1, and by result drafting pattern 1, the difference of visible two method measured results.

Table 1

Factor of porosity mean value	Sample	1	Sample 2	Sample 3	Sample 4	Sample 5
							Conventional analysis	5.12	0.7	6.62	1.29	0.19
Method of the present invention	8.66	6.21	10.68	8.73	7.62

Claims (7)

1. a method for measuring porosity of mud shale, is characterized in that, the method comprises:

Step (1): choose monoblock mud shale testing sample, quality measurement M _o, measure block cumulative volume V _o, the block density ρ of calculating mud shale _b,

wherein, the monoblock mud shale testing sample of choosing, its mass M _obe more than or equal to 100g;

Step (2): sample is crushed to granularity and is less than or equal to the minimum non-open pore of sample, get a certain amount of M ₁, M ₁≤ M _o;

Step (3): the sample of taking-up is distilled to extracting, until water production rate keeps stable;

Step (4): by taking out through the sample of distillation extracting, be dried to steady quality;

Step (5): dried sample is taken out, measure particle volume V _g;

Step (6): calculation sample factor of porosity Φ,

wherein,

2. method for measuring porosity of mud shale according to claim 1, wherein, in described step (1), be adopt Archimedes's mercury immersion method based on buoyancy, mercury displacement process, kind of calliper method or based on buoyancy with fluid but not Archimedes's method of mercury measure cumulative volume method and measure block cumulative volume V _o.

3. method for measuring porosity of mud shale according to claim 1, wherein, described step is crushed to 12 orders or thinner by sample in (2).

4. method for measuring porosity of mud shale according to claim 1 wherein, is to use Dean-Stark extraction plant to distill extracting to the sample taking out in described step (3).

5. method for measuring porosity of mud shale according to claim 1, wherein, in described step (4), be by through distillation extracting sample at 110 ℃ of freeze-day with constant temperature to steady quality.

6. method for measuring porosity of mud shale according to claim 1 wherein, is to adopt the two chambers of Boyle law method to measure the particle volume V of dried sample in described step (5) _g.

7. method for measuring porosity of mud shale according to claim 1, the method also comprises the water saturation S that calculates mud shale according to following formula _w, oil saturation S _oand/or gas saturation S _gprocess:

wherein, V _wfor the volume of extracting water outlet in step (3);

wherein, M ₂for dried sample quality in step (4), ρ _ofor the fuel-displaced density of extracting in step (3), ρ _wfor the density of extracting water outlet in step (3);

S _g=100-S _w-S _o。

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