CN106290102A - The method of the permeability of test proppant and the method for flow conductivity - Google Patents

Abstract

The present invention relates to test method and the method for flow conductivity of the permeability of proppant.The method comprises the following steps, step one: without under ambient pressure, by quality be m, true density be that the proppant of ρ is laid in the fixing container that floor space is A, laid height is W_f0, the pore throat radius in described laid proppant duct is r₀, tortuosity be τ₀.Step 2: using simulated formation pressure to be compressed proppant, the laid height after pressurization is W_f1, by m, ρ, A, W_f0、W_f1、r₀、τ₀Obtain by the porosity φ of the proppant after compressing₁, the pore throat radius r in duct₁With tortuosity τ₁.Under simulated formation pressure, permeability k of proppant₁It is expressed from the next

Description

The method of the permeability of test proppant and the method for flow conductivity

Technical field

The present invention relates to exploration of oil and gas field, development field, particularly to a kind of method testing proppant permeability. The method that the invention still further relates to test the flow conductivity of proppant.

Background technology

Fracturing is the important method of well production increment, water injection well stimulation.Along with the development of oil exploration industry, Fracturing the most extensively answers ground for the exploitation of various oil gas fields.In hydraulic fracturing technology, support Agent has important function.

Proppant is the granule brought into by fracturing fluid and be supported in crack produced by pressure break.Proppant particles heap Amass together, between proppant particles, define the passage flow through for fluid.Use proppant purpose be After stopping infusion, crack is made still to keep open configuration when bottom pressure deteriorates to less than burden pressure, thus Form a flow channel with high flow conductivity, effectively oil gas is imported Oil/gas Well.At present, domestic The proppant of outer use mainly includes quartz sand, coated sand, and resin coating walnut shell, by bauxite, height The haydite that ridge soil or other material are made, and the Novel propping agent such as low-density propping agent, deformable proppant.

Flow conductivity is an important indicator of proppant.In the prior art, simulate ground the most in the lab The method of layer condition and fluid flowing obtains the flow conductivity of proppant.But, required for this method time Between long, and experimental facilities is complicated, it is difficult to obtain the flow conductivity of proppant quickly and easily.

Summary of the invention

For the problems referred to above, the present invention proposes a kind of proppant flow conductivity method of testing.According to the present invention's Method, does not carry out fluid experiment and just can accurately test out the flow conductivity of proppant, simple and fast.

According to the first aspect of the invention, the method for the permeability of test proppant comprises the following steps,

Step one: without under ambient pressure, by quality be m, true density is that the proppant of ρ is laid in floor space is In the fixing container of A, laid height is W_f0, the pore throat radius in laid proppant duct is r₀, duct circuitous Curvature is τ₀,

Step 2: use simulated formation pressure that described proppant is compressed, the laid height of pressurization rear support agent Degree is W_f1, by m, ρ, A, W_f0、W_f1、r₀、τ₀Obtain by the porosity φ in the proppant after compressing₁、 The pore throat radius r in duct₁With tortuosity τ₁,

Step 3: under this simulated formation pressure, permeability k of described proppant₁It is expressed from the next

$k_1=\frac{{\mathrm{\φ}}_1{r_1}^2}{8{{\mathrm{\τ}}_1}^2}.$

The method of the present invention draws the proppant infiltration under simulated formation pressure indeed through Theoretical Calculation Rate k₁.This method only needs to learn some physical parameters of proppant, and the part in these physical parameters, Such as true density ρ is steady state value and is well known to the skilled artisan in the art；And other physical parameters, Such as m, A, W_f0、W_f1、r₀、τ₀It is then that those skilled in the art uses method of the prior art simple Ground is measured, is calculated and obtain, and can thus be calculated by the porosity φ in the proppant after compressing₁, hole The pore throat radius r in road₁With tortuosity τ₁.Therefore, the method according to the invention is only by Theoretical Calculation and simple survey Permeability k of the most available proppant of amount₁, and without using fluid to test, simple and fast.

It has been found that the accumulation mode of proppant particles can be described by body-centered cubic.In this case, Can be supported the pore throat radius r of agent inner duct by geometrical calculation₀And the tortuosity τ in duct₀.At one In embodiment, pore throat radius r₀And the tortuosity τ in duct₀It is expressed from the next respectively

$r_0=\frac{2\sqrt{3}-3}{6}D,$

${\mathrm{\τ}}_0=\frac{\sqrt{6}}{2},$

Wherein, D is the diameter of proppant particles.

Preferably, pore throat radius r₁It is expressed from the next

r₁=K × r₀,

Wherein, for the proppant determined, COEFFICIENT K is the constant less than 1 and more than zero.

Owing to proppant is compressed, therefore the piling height of proppant can reduce, and the hole between proppant particles is empty Between compressed, therefore the pore throat radius in duct also can reduce.In a preferred embodiment, COEFFICIENT K by Following formula represents

$K=\frac{W_{f1}}{W_{f0}},$

Due to W_f1And W_f0Can simply and accurately measure, therefore COEFFICIENT K can also be simply and accurately Draw, and then pore throat radius r can be calculated₁。

In one embodiment, porosity φ₁It is expressed from the next

${\mathrm{\φ}}_1=\frac{{\mathrm{AW}}_{f1}-\frac{m}{\mathrm{\ρ}}}{{\mathrm{AW}}_{f1}}$

In one embodiment, tortuosity τ₁It is expressed from the next

${\mathrm{\τ}}_1=\sqrt{\frac{1}{2}{\left(\frac{W_{f1}}{W_{f0}}\right)}^2+1}.$

Due to m, ρ, A, W_f1And W_f0Can simply and accurately obtain, therefore porosity φ₁With tortuous Degree τ₁Can also simply and accurately obtain.

According to the second aspect of the invention, it is proposed that the method for the flow conductivity of test proppant.This method bag Include use according to test proppant permeability method mentioned above, under described simulated formation pressure, described The flow conductivity k of support agent₁W_f1It is expressed from the next

$k_1{W}_{f1}=\frac{{\mathrm{\φ}}_1{r}_1^2}{8{\mathrm{\τ}}_1^2}{W}_{f1}.$

Compared with prior art, it is an advantage of the current invention that: the method for (1) present invention only by Theoretical Calculation and Simple permeability k measuring the most available proppant₁With flow conductivity k₁W_f1, and without using fluid to carry out reality Test, simple and fast.(2) the support dosage required for the method for the present invention is less, decreases waste.

Detailed description of the invention

Below in conjunction with embodiment, the invention will be further described.

Embodiment 1:

Choose polystyrene proppant as the first proppant.Quality m of the first proppant is 8.19g, the closeest Degree ρ is 1.046g/cm³, the diameter D of granule is 638 μm.

It is 20.26cm that first proppant is laid on floor space A²Container in, laid height W_f0For 0.64cm. Use simulated formation pressure that the first proppant is compressed, and to record the laid height after compression be W_f1.By m, ρ、A、W_f0、W_f1、r₀、τ₀Obtain by the porosity φ of the first proppant after compressing₁, the pore throat half in duct Footpath r₁With tortuosity τ₁.Finally, under simulated formation pressure, it is calculated oozing of the first proppant by formula 1 Rate k thoroughly₁, result is as shown in table 1.

$k_1=\frac{{\mathrm{\φ}}_1{r_1}^2}{8{{\mathrm{\τ}}_1}^2}$ Formula 1.

The flow conductivity k of the first proppant is calculated by formula 2₁W_f1, result is as shown in table 1.

$k_1{W}_{f1}=\frac{{\mathrm{\φ}}_1{r}_1^2}{8{\mathrm{\τ}}_1^2}{W}_{f1}$ Formula 2.

Embodiment 2:

Choose resin coating walnut shell as the second proppant.Quality m of the second proppant is 10.08g, the closeest Degree ρ is 1.254g/cm³, the diameter D of the granule of the second proppant is 635 μm.

It is 20.26cm that second proppant is laid on floor space A²Container in, laid height W_f0For 0.64cm. Use simulated formation pressure that the second proppant is compressed, and to record the laid height after compression be W_f1.By m, ρ、A、W_f0、W_f1、r₀、τ₀Obtain by the porosity φ of the second proppant after compressing₁, the pore throat half in duct Footpath r₁With tortuosity τ₁.Finally, under simulated formation pressure, it is calculated oozing of the second proppant by formula 3 Rate k thoroughly₁, result is as shown in table 1.

$k_1=\frac{{\mathrm{\φ}}_1{r_1}^2}{8{{\mathrm{\τ}}_1}^2}$ Formula 3.

The flow conductivity k of the second proppant is calculated by formula 4₁W_f1, result is as shown in table 1.

$k_1{W}_{f1}=\frac{{\mathrm{\φ}}_1{r}_1^2}{8{\mathrm{\τ}}_1^2}{W}_{f1}$ Formula 4.

Comparative example 1:

Choose the first proppant in embodiment 1.Use " fracturing propping agents filling bed short-term of the prior art Method is recommended in flow conductivity evaluation " (industry standard Y/T 6302-2009) test the permeability of the first proppant With flow conductivity (test condition: the first initial laid height of proppant is 0.64cm).Result such as table 1 institute Show.

Comparative example 2:

Choose the second proppant in embodiment 2.Use " fracturing propping agents filling bed short-term of the prior art Method is recommended in flow conductivity evaluation " (industry standard Y/T 6302-2009) test the permeability of the second proppant With flow conductivity (test condition: the second initial laid height of proppant is 0.64cm).Result such as table 1 institute Show.

Table 1

As can be seen from Table 1, use the permeability of proppant that the method for the present invention draws and flow conductivity and make The permeability and the flow conductivity that draw by the test method of prior art are of substantially equal, therefore use the side of the present invention Method can evaluate permeability and the flow conductivity of proppant exactly.

Although by reference to preferred embodiment, invention has been described, but without departing from the scope of the present invention In the case of, it can be carried out various improvement.The every technical characteristic being previously mentioned in each embodiment all can be appointed Meaning mode combines.The invention is not limited in specific embodiment disclosed herein, but include falling into right All technical schemes in the range of requirement.

Claims (8)

1. test the permeability method of proppant, comprise the following steps,

Step one: without under ambient pressure, by quality be m, true density is that the proppant of ρ is laid in floor space is In the fixing container of A, laid height is W_f0, the pore throat radius in the duct of described laid proppant is r₀, hole The tortuosity in road is τ₀,

Step 2: use simulated formation pressure that described proppant is compressed, the laid height of pressurization rear support agent Degree is W_f1, by m, ρ, A, W_f0、W_f1、r₀、τ₀Obtain by the porosity φ in the proppant after compressing₁、 The pore throat radius r in duct₁With tortuosity τ₁,

Step 3: under described simulated formation pressure, permeability k of described proppant₁It is expressed from the next

$k_1=\frac{{\mathrm{\φ}}_1{r_1}^2}{8{{\mathrm{\τ}}_1}^2}.$

Method the most according to claim 1, it is characterised in that described pore throat radius r₀It is expressed from the next

$r_0=\frac{2\sqrt{3}-3}{6}D,$

Wherein, D is the diameter of described proppant particles.

Method the most according to claim 1, it is characterised in that the tortuosity τ in described duct₀By following formula Represent

${\mathrm{\τ}}_0=\frac{\sqrt{6}}{2}.$

4. according to the method according to any one of Claim 1-3, it is characterised in that described pore throat radius r₁It is expressed from the next

r₁=K × r₀,

Wherein, for the proppant determined, COEFFICIENT K is the constant less than 1 and more than zero.

Method the most according to claim 4, it is characterised in that described COEFFICIENT K is expressed from the next

$K=\frac{W_{f1}}{W_{f0}}.$

6. according to the method according to any one of claim 1 to 5, it is characterised in that described porosity φ₁ It is expressed from the next

${\mathrm{\φ}}_1=\frac{{\mathrm{AW}}_{f1}-\frac{m}{\mathrm{\ρ}}}{{\mathrm{AW}}_{f1}}.$

7. according to the method according to any one of claim 1 to 6, it is characterised in that described tortuosity τ₁ It is expressed from the next

${\mathrm{\τ}}_1=\sqrt{\frac{1}{2}{\left(\frac{W_{f1}}{W_{f0}}\right)}^2+1}.$

8. the method testing the flow conductivity of proppant, appoints according in claim 1 to 7 including using One described test proppant permeability method, under described simulated formation pressure, the water conservancy diversion of described proppant Ability k₁W_f1It is expressed from the next

$k_1{W}_{f1}=\frac{{\mathrm{\φ}}_1{r}_1^2}{8{\mathrm{\τ}}_1^2}{W}_{f1}.$