CN104990856A - Apparatus for measuring permeability of low permeation rock core, and method thereof - Google Patents

Abstract

The invention belongs to the field of petroleum engineering, and concretely relates to an experiment apparatus for measuring the permeability of a low permeation rock core, and a method thereof. The apparatus for measuring the permeability of the low permeation rock core comprises an inlet end pressure cap, an outlet end pressure cap, a curing glue sleeve, a carbon oxide gas bottle, a glass funnel, a first scale, a vacuum pump, a polyfluortetraethylene pipe and a second scale, and three ports of a first tee joint are respectively connected with the outlet of the inlet end pressure cap, the carbon dioxide gas bottle and the glass funnel through pipelines and valves; the glass funnel is vertically arranged, and one side of the glass funnel is vertically provided with the first scale; and three ports of a second tee joint are respectively connected with the outlet of the outlet end pressure cap, the vacuum pump and the polyfluortetraethylene pipe through pipelines and valves, the polyfluortetraethylene pipe is horizontally fixed, the polyfluortetraethylene pipe, a tested rock core and the axis of the first tee joint are in a same horizontal line, and one side of the polyfluortetraethylene pipe is provided with the second scale in a parallel manner. The experiment apparatus for measuring the permeability of the low permeation rock core has the advantages of small dead volume and high metering precision.

Description

Measure the device and method of flow in low permeability core permeability

Technical field

The invention belongs to petroleum engineering field, particularly, relate to the experimental provision and method in a kind of oil and gas development field, the permeability of rock core measured, especially, relate to a kind of experimental provision and the method for measuring flow in low permeability core permeability.

Background technology

Flow in low permeability core refers to that permeability is between (0.1 ~ 50) × 10 ^-3μm porous medium, the monophasic fluid Seepage problems in flow in low permeability core is widely used in fields such as energy development, hydraulic engineering, nuclear waste disposals background.China current proven reserves and development reserves in, hyposmosis reserves account for very large ratio.The permeability of rock characterizes the ability that rock allows fluid to pass through, and is one of the most basic physical parameter of describing reservoir rock.Flow in low permeability core hole shouts that size is small, permeability is low, conventional rock flowing experiment is because of factors such as instrument dead volume, volatilize fluid, experimental error, rock are completely unsaturated, be difficult to the hypotonic rock inlet pressure of Measurement accuracy and rate of discharge, cause measurement result and actual physics process to there is bigger difference, and result is difficult to coincide actual with production.

Summary of the invention

For overcoming the defect of prior art, the invention provides a kind of can the experimental provision of Measurement accuracy flow in low permeability core permeability and method.

For solving the problems of the technologies described above, the present invention adopts following proposal:

Measure the device of flow in low permeability core permeability, comprise: inlet end pressure cap, endpiece pressure cap, solidification gum cover, dioxide bottle, glass funnel, the first scale, vacuum pump, polyfluortetraethylene pipe, the second scale, wherein: entrance pressure cap and outlet pressure cap clamp the both ends of the surface of tested rock core, and tested rock core is horizontally disposed with; Three ports of the first threeway are connected respectively by the outlet of pipeline and entrance pressure cap, dioxide bottle, glass funnel, the pipeline that first threeway is connected with the outlet of entrance pressure cap is horizontally disposed with, the pipeline that first threeway is connected with dioxide bottle is provided with the first valve, the pipeline that first threeway is connected with glass funnel is silicone tube, and silicone tube is provided with the second valve; Glass funnel is vertically placed, and the side of glass funnel is vertically provided with the first scale, and the lower end of the first scale is mutually neat with the center of entrance pressure cap; Three ports of the second threeway are connected with the outlet of outlet pressure cap, vacuum pump, polyfluortetraethylene pipe respectively by pipeline; The pipeline that second threeway is connected with vacuum pump is provided with the 3rd valve; The pipeline that second threeway is connected with polyfluortetraethylene pipe is provided with the 4th valve, teflon bore is 1mm, length is 1 ~ 2m, polyfluortetraethylene pipe level is fixed, with the axis of tested rock core in the same horizontal line, the parallel placement second in the side scale of polyfluortetraethylene pipe.

Compared with prior art, beneficial effect of the present invention is as follows:

1, flow in low permeability core permeability measuring apparatus reduces the dead volume of instrument as much as possible, avoids the impact of dead volume on measurement result;

2, the rock inlet pressure of flow in low permeability core permeability measuring apparatus adopts liquid-column height metering, and exit velocity adopts the polyfluortetraethylene pipe of little internal diameter to measure, and eliminates the impact of resistance to flow in upstream and downstream flexible pipe simultaneously, improves the precision of measurement;

3, by designed experimental technique, can ensure that tested rock core is that single-phase liquid is completely saturated;

4, experimental provision one-piece construction is simple, is easy to make and maintenance, and it is low to make maintenance cost.

Accompanying drawing explanation

Fig. 1 is the apparatus structure schematic diagram measuring flow in low permeability core permeability;

Fig. 2 is inlet end pressure cap (endpiece pressure cap) schematic diagram;

Fig. 3 is the structural representation that spreader plate contacts tested rock core end face side;

In figure: 1, inlet end pressure cap, 2, endpiece pressure cap, 3, tested rock core, 4, gum cover is solidified, the 5, first threeway, the 6, first valve, 7, dioxide bottle, the 8, second valve, 9, silicone tube, 10, glass funnel, 11, liquid level, the 12, first scale, 13, the second threeway, 14, the 3rd valve, 15, vacuum pump, the 16, the 4th valve, 17, polyfluortetraethylene pipe, 18, the second scale, 19, pressure cap shell, 20, spreader plate, 21, pressure cap outlet, 22, spreader plate groove, 23, spreader plate pod apertures, 24, spreader plate is protruding.

Embodiment

As shown in Figure 1, Figure 2, Figure 3 shows, measure the device of flow in low permeability core permeability, comprise: inlet end pressure cap 1, endpiece pressure cap 2, solidification gum cover 4, dioxide bottle 7, glass funnel 10, first scale 12, vacuum pump 15, polyfluortetraethylene pipe 17, second scale 18, wherein:

Tested rock core 3 is the smooth right cylinders of both ends of the surface, and diameter is 2.5cm; The structure of inlet end pressure cap 1 and endpiece pressure cap 2 and measure-alike, overall diameter is 2.5cm, identical with the diameter of tested rock core 3; Entrance pressure cap 1 and outlet pressure cap 2 clamp the both ends of the surface of tested rock core 3, and tested rock core 3 is horizontally disposed with, and the inlet end pressure cap 1 after clamping, endpiece pressure cap 2, tested rock core 3 circumferentially seal by solidification gum cover 4.

Inlet end pressure cap 1, endpiece pressure cap 2 are formed by fixedly connecting by pressure cap shell 19 and spreader plate 20, the side that spreader plate 20 contacts with tested rock core 3 is radially provided with groove 22 with hoop, groove 22 width is 2 ~ 3mm, the degree of depth is 1 ~ 2mm, pod apertures 23 is provided with in groove 22, the diameter of pod apertures 23 is 2mm, and spreader plate 20 makes to there is certain distance between tested rock core 3 and pod apertures 23 by protruding 24, makes fluid evenly to flow into along the end face of tested rock core 3 or to flow out; The side that spreader plate 20 is opposing with tested rock core and pressure cap shell 20 form the cavity that thickness is 1 ~ 2mm, to ensure fluid well-distributing along pod apertures 23 by spreader plate 20, and reduce dead volume as far as possible; The center of pressure cap shell 20 is provided with outlet 21, for inflow or the outflow of fluid.

Three ports of the first threeway 5 are connected respectively by the outlet 21 of pipeline and entrance pressure cap 1, dioxide bottle 7, glass funnel 10, the pipeline that first threeway 5 is connected with the outlet 21 of entrance pressure cap 1 is horizontally disposed with, the pipeline that first threeway 5 is connected with dioxide bottle 7 is provided with the first valve 6, the pipeline that first threeway 5 is connected with glass funnel 10 is silicone tube 9, and silicone tube 9 is provided with the second valve 8; Glass funnel 10 is vertically placed, the side of glass funnel 10 is vertically provided with the first scale 12, the lower end of the first scale 12 is mutually neat with the center (i.e. the export center of entrance pressure cap) of entrance pressure cap 1, scale 12 is applied to the liquid-column height of tested rock core upstream for measuring, i.e. upstream pressure value.

Three ports of the second threeway 13 are connected with the outlet 21 of outlet pressure cap 2, vacuum pump 15, polyfluortetraethylene pipe 17 respectively by pipeline; The pipeline that second threeway 13 is connected with vacuum pump 15 is provided with the 3rd valve 14; The pipeline that second threeway 14 is connected with polyfluortetraethylene pipe 17 is provided with the 4th valve 16, polyfluortetraethylene pipe 17 internal diameter is 1mm, length is 1 ~ 2m, polyfluortetraethylene pipe 17 level is fixed, with the axis of tested rock core 3 in the same horizontal line, the parallel placement second in the side scale 18 of polyfluortetraethylene pipe 17, the start index of the second scale 18 and the outlet of the 4th valve 16 are neat mutually, in order to measure the displacement of liquid level in polyfluortetraethylene pipe 17.

Tested rock core 3 is clamped with entrance pressure cap 1, outlet pressure cap 2, be that the epoxy resin of 1:0.8 and hardening agent uniform stirring are deployed into solidification glue with mass ratio, ring week uniform application a layer thickness of entrance pressure cap 1 first after clamping, outlet pressure cap 2 and tested rock core 3 is that 1mm solidifies glue, leave standstill 6 hours, solidification glue can play effect seal tested rock core, prevents solidifying glue simultaneously and enters tested rock core because of capillary force effect imbibition; After hardening agent solidification to be applied, continue uniform application solidification glue, until solidification glue thickness is 3 ~ 5mm, to ensure the seal protection forming larger intensity around tested rock core, and certain pressure can be born; Leave standstill smearing the entrance pressure cap 1 after hardening agent, outlet pressure cap 2 and tested rock core 3, until the complete consolidation of solidification glue forms solidification gum cover 4, by the tested rock core horizontal positioned after consolidation.

Measure the method for flow in low permeability core permeability, adopt the device of above-mentioned measurement flow in low permeability core permeability, step is as follows:

(1), close the first valve 6, second valve 8, the 4th valve 16, open the 3rd valve 14, with vacuum pump 15, carried out to tested rock core 3 first time and vacuumize process;

(2), exhaust vacuum after, close the 3rd valve 14, open the first valve 6, by dioxide bottle 7 to the saturated carbon dioxide of tested rock core 3;

(3), after saturated 10 ~ 20 minutes, close the first valve 6, open three valves 14, again process is vacuumized to tested rock core 3, after having vacuumized, close the 3rd valve 14; This operation can ensure higher vacuum tightness, even if there is a small amount of CO2, also can be dissolved by the follow-up liquid entering tested rock core and flow out tested rock core with flowing, ensureing that tested rock core is that single-phase liquid is completely saturated;

(4) distilled water configuration salinity, is used to be the NaCl solution of 1%, then prepared NaCl solution is heated, in order to reduce the air dissolved in NaCl solution, the NaCl solution clay mineral water-swellable that can reduce in tested rock core affects the problem of permeability simultaneously, then the NaCl solution after process is poured in glass funnel 10, open valve 8, adopt the saturated tested rock core 3 of way of vacuum self-priming, after 4 ~ 6 hours, liquid level 11 in glass funnel 10 no longer reduces, and tested rock core 3 is saturated complete;

(5), in glass funnel 10 add a certain amount of NaCl solution, make liquid level 11 be positioned at the middle and upper part of glass funnel 10, measured the height h (cm) of liquid level 11 in glass funnel 10 by the first scale 12;

(6) the 4th valve 16, is opened, when liquid is after the 4th valve 16 flows into polyfluortetraethylene pipe 17, the displacement S (mm) of liquid level in polyfluortetraethylene pipe 17 is measured by the second scale 18, and record time t (s) used, carry out in process at flowing experiment, note in glass funnel 10, supplementing NaCl solution in real time, keep the invariant position of liquid level 11;

(7) the permeability k of tested rock core, is calculated:

$k=\frac{4\mathrm{\μ}QL}{{\mathrm{\πd}}^2\mathrm{\Δ}p}---\left(1\right)$

Wherein, $Q=\frac{{{\mathrm{\πd}}_2}^{2}S}{4000t}---\left(2\right)$

Δp＝Δp _h-(Δp ₁+Δp ₂) (3)

Δp _h＝10 ^-4ρgh (4)

${\mathrm{\Δp}}_1=128\×{10}^{-6}\frac{{\mathrm{Q\μl}}_1}{{\mathrm{\πd}}_1^4}---\left(5\right)$

${\mathrm{\Δp}}_2=64\×{10}^{-6}\frac{Q\mathrm{\μ}S}{{\mathrm{\πd}}_2^4}---\left(6\right)$

In formula: the permeability of k-tested rock core, μm ²;

μ-NaCl solution viscosity, mPas;

The flow of Q-NaCl solution in tested rock core, cm ³/ s;

L-tested rock core length, cm;

π-circular constant;

D-tested core diameter, cm;

The flow differential pressure at Δ p-tested rock core two ends, 10 ^-1mPa;

D ₂the internal diameter of-polyfluortetraethylene pipe, mm;

The displacement of liquid level in S-polyfluortetraethylene pipe, mm;

The time that in t-polyfluortetraethylene pipe, the mobile S of liquid level is used, second;

Δ p _hthe general pressure that-upstream fluid column produces, 10 ^-1mPa;

Δ p ₁droop loss in-silicone tube, 10 ^-1mPa;

Δ p ₂droop loss in-polyfluortetraethylene pipe, 10 ^-1mPa;

ρ-NaCl solution density, g/cm ³;

G-acceleration of gravity, 9.8m/s ²;

The height of h-liquid level, cm;

L ₁the length of-silicone tube, cm;

D ₁the internal diameter of-silicone tube, mm.

Claims (4)

1. measure the device of flow in low permeability core permeability for one kind, comprise: inlet end pressure cap, endpiece pressure cap, solidification gum cover, dioxide bottle, glass funnel, the first scale, vacuum pump, polyfluortetraethylene pipe, the second scale, it is characterized in that: entrance pressure cap and outlet pressure cap clamp the both ends of the surface of tested rock core, and tested rock core is horizontally disposed with; Three ports of the first threeway are connected respectively by the outlet of pipeline and entrance pressure cap, dioxide bottle, glass funnel, the pipeline that first threeway is connected with the outlet of entrance pressure cap is horizontally disposed with, the pipeline that first threeway is connected with dioxide bottle is provided with the first valve, the pipeline that first threeway is connected with glass funnel is silicone tube, and silicone tube is provided with the second valve; Glass funnel is vertically placed, and the side of glass funnel is vertically provided with the first scale, and the lower end of the first scale is mutually neat with the center of entrance pressure cap; Three ports of the second threeway are connected with the outlet of outlet pressure cap, vacuum pump, polyfluortetraethylene pipe respectively by pipeline; The pipeline that second threeway is connected with vacuum pump is provided with the 3rd valve; The pipeline that second threeway is connected with polyfluortetraethylene pipe is provided with the 4th valve, teflon bore is 1mm, length is 1 ~ 2m, polyfluortetraethylene pipe level is fixed, with the axis of tested rock core in the same horizontal line, the parallel placement second in the side scale of polyfluortetraethylene pipe.

2. the device of measurement flow in low permeability core permeability according to claim 1, it is characterized in that: inlet end pressure cap, endpiece pressure cap are formed by fixedly connecting by pressure cap shell and spreader plate, the side that spreader plate contacts with tested rock core is radially provided with groove with hoop, recess width is 2 ~ 3mm, the degree of depth is 1 ~ 2mm, pod apertures is provided with in groove, the diameter of pod apertures is 2mm, spreader plate and the opposing side of tested rock core and pressure cap shell form the cavity that thickness is 1 ~ 2mm, and the center of pressure cap shell is provided with outlet.

3. the device of the measurement flow in low permeability core permeability according to claim 1-2, is characterized in that: tested rock core is the smooth right cylinders of both ends of the surface, and diameter is 2.5cm; The structure of inlet end pressure cap and endpiece pressure cap and measure-alike, overall diameter is 2.5cm.

4. measure the method for flow in low permeability core permeability, adopt the device of the measurement flow in low permeability core permeability described in claim 1-3, step is as follows:

(1), close the first valve, the second valve, the 4th valve, open the 3rd valve, with vacuum pump, carried out to tested rock core first time and vacuumize process;

(2), exhaust vacuum after, close the 3rd valve, open the first valve, by dioxide bottle to the saturated carbon dioxide of tested rock core;

(3), after saturated 10 ~ 20 minutes, close the first valve, open three valves, again process is vacuumized to tested rock core, after having vacuumized, close the 3rd valve;

(4) distilled water configuration salinity, is used to be the NaCl solution of 1%, then prepared NaCl solution is heated, then the NaCl solution after process is poured in glass funnel, open valve, adopt the saturated tested rock core of way of vacuum self-priming, after 4 ~ 6 hours, the liquid level in glass funnel no longer reduces, and tested rock core is saturated complete;

(5), in glass funnel add NaCl solution, make liquid level be positioned at the middle and upper part of glass funnel, by the height h of liquid level in the first tape measure glass funnel;

(6), open the 4th valve, when liquid flows into after polyfluortetraethylene pipe through the 4th valve, by the displacement S of liquid level in the second tape measure polyfluortetraethylene pipe, and record time t used; Carry out in process at flowing experiment, in glass funnel, supplement NaCl solution in real time, keep the invariant position of liquid level;

(7) the permeability k of tested rock core, is calculated:

$k=\frac{4\mathrm{\μ}QL}{{\mathrm{\πd}}^2\mathrm{\Δ}p}---\left(1\right)$

Wherein, $Q=\frac{{{\mathrm{\πd}}_2}^{2}S}{4000t}---\left(2\right)$

Δp＝Δp _h-(Δp ₁+Δp ₂) (3)

Δp _h＝10 ^-4ρgh (4)

${\mathrm{\Δp}}_1=128\×{10}^{-6}\frac{{\mathrm{Q\μl}}_1}{{\mathrm{\πd}}_1^4}---\left(5\right)$

${\mathrm{\Δp}}_2=64\×{10}^{-6}\frac{Q\mathrm{\μ}S}{{\mathrm{\πd}}_2^4}---\left(6\right)$

In formula: the permeability of k-tested rock core, μm ²;

μ-NaCl solution viscosity, mPas;

The flow of Q-NaCl solution in tested rock core, cm ³/ s;

L-tested rock core length, cm;

π-circular constant;

D-tested core diameter, cm;

The flow differential pressure at Δ p-tested rock core two ends, 10 ^-1mPa;

D ₂the internal diameter of-polyfluortetraethylene pipe, mm;

The displacement of liquid level in S-polyfluortetraethylene pipe, mm;

The time that in t-polyfluortetraethylene pipe, the mobile S of liquid level is used, second;

Δ p _hthe general pressure that-upstream fluid column produces, 10 ^-1mPa;

Δ p ₁droop loss in-silicone tube, 10 ^-1mPa;

Δ p ₂droop loss in-polyfluortetraethylene pipe, 10 ^-1mPa;

ρ-NaCl solution density, g/cm ³;

G-acceleration of gravity, 9.8m/s ²;

The height of h-liquid level, cm;

L ₁the length of-silicone tube, cm;

D ₁the internal diameter of-silicone tube, mm.