CN102914485B - Device and method for testing deviation factor of natural gas in porous medium - Google Patents

Abstract

The invention relates to a device and method for testing a deviation factor of a natural gas in a porous medium. The device is composed of a porous medium system, a data acquiring and processing system, a PVT (Pressure-Volume-Temperature) testing unit, an intermediate container, a gas meter, an oven and a pump, wherein the porous medium system is formed by serially connecting five sand-filled pipes. The method comprises the steps of: filling quartz sands in the give sand-filled pipes; measuring a pore volume of each sand-filled pipe and a volume of a pipeline between pressure sensors; rising the temperature of the oven to a formation temperature T; testing a balance pressure P1 in a first sand-filled pipe and balance pressures P2, P3, P4 and P5 of other sand-filled pipes when being connected in series; obtaining volumes V2, V3, V4 and V5 of the natural gas when the pressures are P2, P3, P4 and P5 through volume expansion; and obtaining a deviation factor of the natural gas in the porous medium. The device and method for testing the deviation factor of the natural gas in the porous medium, disclosed by the invention, has the advantages of considering influences from adsorption function of the porous medium to the deviation factor of the natural gas, thereby enabling the testing result to be closer to the deviation factor of the natural gas in the true storage layer and guiding the production practice better.

Description

The determinator of rock gas deviation factors and method in a kind of porous medium

Technical field

The present invention relates to measure in a kind of porous medium the device and method of rock gas deviation factors, especially for oil and gas industry, consider to measure under reservoir porous high temperature and high pressure environment the device and method of rock gas deviation factors.

Background technology

The deviation factors of rock gas is one of physical parameter of rock gas, be mainly used in gas reservoir geologic reserve and workable reserve and calculate, well test analysis, the analysis of manufacturing capability, production performance analysis, numerical simulation, production system analysis, christmas technological design and ground surface works design.The experimental technique of current known rock gas deviation factors is to carry out experiment test in the conventional PVT test cell under not considering reservoir porous environment.And rock gas is to be in the porous medium of reservoir, under this deviation factors that will cause conventional gas and true reservoir conditions, the deviation factors of rock gas exists deviation.

Therefore, research is considered the experimental determination device of rock gas deviation factors under reservoir porous high temperature and high pressure environment and method is of great immediate significance and directive significance: (1) has considered that porous medium specific area is large, and suction-operated is outstanding feature more; (2) consider the impact of Porous Medium Adsorption effect on rock gas deviation factors, thereby made measurement result more approach the deviation factors of true reservoir rock gas, instructed better production practices.

Summary of the invention

The object of the present invention is to provide the determinator of rock gas deviation factors in a kind of porous medium, this principle of device is reliable, rational in infrastructure, simple to operate, owing to having considered reservoir porous and high temperature and high pressure environment, the rock gas deviation factors of measuring by this device more approaches the deviation factors of true reservoir rock gas, advantageously instructs production practices.

Another object of the present invention is to provide the method for utilizing said apparatus to measure rock gas deviation factors in porous medium, the rock gas deviation factors of the method test, the impact of the existence of having reacted more truly reservoir porous on rock gas deviation factors.

The present invention not only can be used for considering the rock gas deviation factors experimental study under porous medium high temperature and high pressure environment, also can carry out the experiment test of other physical parameter of rock gas (volume factor, thermal expansivity etc.).The top pressure 100MPa that this experimental technique can reach, 200 ℃ of maximum temperatures.

For reaching above technical purpose, the invention provides following technical scheme.

The determinator of rock gas deviation factors in a kind of porous medium, mainly by porous medium system, data acquisition and processing system, PVT test cell, intermediate receptacle, gasometer, baking oven, pump, formed, described porous medium system is in series by 5 fill out sand tube, described porous medium system is connected with intermediate receptacle with PVT test cell respectively, described PVT test cell is connected with pump respectively with intermediate receptacle, and described porous medium system is placed in baking oven and is connected gasometer with PVT test cell; Described data acquisition and processing system comprises temperature sensor, pressure transducer and computing machine, described porous medium system is connected with computing machine by temperature sensor, pressure transducer, and the temperature and pressure in temperature sensor, pressure sensor monitoring fill out sand tube is also passed to computing machine by data; Between the fill out sand tube of described porous medium system, between porous medium system and PVT test cell, between intermediate receptacle, all have a valve.

Utilize said apparatus to measure the method for rock gas deviation factors in porous medium, comprise the following steps successively:

(1) silica sand of different meshes is filled into respectively in 5 fill out sand tube, the maximum pressure that fill out sand tube bears is 100MPa;

(2) at mark condition (P ₀=0.1MPa, T ₀=20 ℃) under, infusion N used ₂measure successively every fill out sand tube volume of voids and be respectively V _k1, V _k2, V _k3, V _k4, V _k5, between fill out sand tube Bonding pressure sensor, the volume of pipeline is V _c, then discharge N ₂and find time fill out sand tube and pipeline to vacuum state (because pipeline between series connection fill out sand tube is short and internal diameter is less, the pipeline volume connecting between fill out sand tube is ignored) with vacuum pump;

(3) by computing machine, the Temperature Setting of baking oven is become to the formation temperature T of reservoir and is warming up to formation temperature T;

(4) with pump, the rock gas of intermediate receptacle is full of to the first fill out sand tube, wait entering pump when slow, by the pressure in pressure sensor monitoring the first fill out sand tube, when pressure equilibrium, writes down the equalized pressure P in the first fill out sand tube now ₁;

(5) will proceed in PVT test cell through the first fill out sand tube absorption a part of rock gas later, with pump, regulating the pressure of rock gas in PVT test cell is P ₁thereby, obtain rock gas at T, P ₁volume V under condition ₁₁, then keeping pressure is P ₁condition under, the rock gas part in PVT test cell is discharged in gasometer, gas consumption instrumentation measures rock gas at mark condition (P ₀=0.1MPa, T ₀=20 ℃) under volume V ₀, then read the rock gas volume V in PVT test cell after exhaust ₁₂thereby, obtain rock gas at T, P ₁volume change value under condition is V ₁(V ₁=V ₁₁-V ₁₂), utilize the following equation of gas state:

P _ov _o=nRZ ₀t ₀(Z wherein _o=1)

P ₁V ₁=nRZ ₁T，

Thereby obtain the deviation factors of gas in PVT test cell

(6) with vacuum pump, find time the first fill out sand tube to vacuum state, then with pump, the rock gas of intermediate receptacle is full of to the first fill out sand tube, open the valve between the first fill out sand tube and the second fill out sand tube, make the first fill out sand tube and the second fill out sand tube keep UNICOM's state, and the equalized pressure P during by pressure sensor monitoring the first fill out sand tube and the series connection of the second fill out sand tube ₂;

(7) open the valve between the second fill out sand tube and the 3rd fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube and the series connection of the 3rd fill out sand tube ₃, open the valve between the 3rd fill out sand tube and the 4th fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube, the 3rd fill out sand tube and the series connection of the 4th fill out sand tube ₄, open the valve between the 4th fill out sand tube and the 5th fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube, the 3rd fill out sand tube, the 4th fill out sand tube and the series connection of the 5th fill out sand tube ₅;

(8) in PVT test cell, remaining gas being done to spot pressure is P ₂, P ₃, P ₄and P ₅volumetric expansion experiment, thereby obtain pressure, be respectively P ₂, P ₃, P ₄and P ₅time rock gas volume V ₂, V ₃, V ₄, V ₅;

(9) utilize the equation of gas state to obtain the deviation factors of rock gas in PVT test cell and porous medium by formula below:

1) the deviation factors Z of rock gas in PVT test cell _i

The deviation factors of the 1st spot pressure:

2nd, the deviation factors of 4,5 spot pressures:

Note: V _i-1i-1 spot pressure, under formation temperature conditions, the volume of rock gas in PVT test cell; V _iunder i spot pressure, under formation temperature conditions, the volume of rock gas in PVT test cell.

2) the deviation factors Z ' of rock gas in porous medium ₁

The deviation factors of the 1st spot pressure: Z ' ₁=Z ₁

2nd, the deviation factors of 3,4,5 spot pressures:

Note: V ' ₁=V _c+ V _k1

V′ ₂=V _c+V _k1+V _K2，

By that analogy, $V_i^{\&prime;}=V_c+{\mathrm{<figure-callout\; id="1"\; label="V\; K"\; filenames="HDA00002350278400012.png"\; state="\{\{state\}\}">V</figure-callout>}}_K+\underset{i=2}{\overset{5}{\mathrm{\&Sigma;}}}{V}_{\mathrm{Ki}}.$

Compared with prior art, the present invention has following beneficial effect:

(1) determinator the present invention relates to, principle is reliable, rational in infrastructure, easy and simple to handle, utilize this device can Accurate Determining reservoir porous high temperature and high pressure environment under the deviation factors of rock gas;

(2) can test the deviation factors of considering porous medium and not considering rock gas under porous medium condition simultaneously;

(3) under the reservoir porous condition of testing, rock gas deviation factors more approaches the deviation factors of true reservoir rock gas;

(4) the maximum temperature pressure 100MPa that experiment can reach, 200 ℃ of maximum temperatures.

Accompanying drawing explanation

Fig. 1 is the structural representation of the determinator of rock gas deviation factors in porous medium of the present invention.

In Fig. 1: 1, the first fill out sand tube; 2, the second fill out sand tube; 3, the three fill out sand tube; 4, the four fill out sand tube; 5, the five fill out sand tube; 6, valve; 7, pressure transducer; 8, computing machine; 9, temperature sensor; 10, PVT test cell; 11, pump one; 12, pump two; 13, gasometer; 14, intermediate receptacle; 15, baking oven.

Fig. 2 is the rock gas deviation factors comparison diagram of considering porous medium and not considering porous medium.

Embodiment

Below in conjunction with accompanying drawing, further illustrate the present invention.

Referring to Fig. 1.The determinator of rock gas deviation factors in a kind of porous medium, mainly by porous medium system, data acquisition and processing system, PVT test cell 10, intermediate receptacle 14, gasometer 13, baking oven 15 forms, described porous medium system is by the first fill out sand tube 1, the second fill out sand tube 2, the 3rd fill out sand tube 3, the 4th fill out sand tube 4, the 5th fill out sand tube 5 is in series, described porous medium system is connected with intermediate receptacle 14 with PVT test cell 10 respectively, described PVT test cell 10 and intermediate receptacle 14 are connected with respectively pump 1, pump 2 12, described porous medium system is placed in baking oven 15 and is connected gasometer 13 with PVT test cell 10, described data acquisition and processing system comprises temperature sensor 9, pressure transducer 7 and computing machine 8, and described porous medium system is connected with computing machine 8 by temperature sensor 9, pressure transducer 7, between the fill out sand tube of described porous medium system, between porous medium system and PVT test cell, between intermediate receptacle, all have a valve 6.

Utilize the method for measuring rock gas deviation factors in porous medium described in said apparatus, comprise successively:

1. the silica sand of different meshes is filled into respectively in 5 fill out sand tube;

2. at 20 ℃, under 0.1MPa, with pump 12 notes N ₂record the first fill out sand tube～five fill out sand tube volume of voids V _k1, V _k2, V _k3, V _k4, V _k5respectively be 89.14ml, 16.62ml, 24.56ml, 55.45ml, 92.44ml, the volume V of pipeline between fill out sand tube Bonding pressure sensor _cfor 2ml, then 5 fill out sand tube are vacuumized;

By computing machine by the Temperature Setting of baking oven and be warming up to 80 ℃ of the formation temperatures of reservoir;

4. with pump, the rock gas of intermediate receptacle is full of to the first fill out sand tube, wait entering pump when slow, by the pressure in pressure sensor monitoring the first fill out sand tube, when pressure equilibrium, writes down the pressure P in the first fill out sand tube now ₁for 42.34MPa;

5. will proceed in PVT test cell through the first fill out sand tube absorption a part of rock gas later, utilizing pump 11 to regulate the pressure of rock gas in PVT test cell is P ₁thereby, record the volume V of rock gas under 80 ℃, 42.34MPa condition ₁₁for 25.250ml, then keeping pressure is under the condition of 42.34MPa, and the rock gas part in PVT test cell is discharged in gasometer, measures rock gas at mark condition (P ₀=0.1MPa, T ₀=20 ℃) under volume V ₀for 225ml, then read the rock gas volume V in PVT test cell after exhaust ₁₂for 25.110ml, thereby obtain rock gas at T, P ₁volume change value V under condition ₁(V ₁=V ₁₁-V ₁₂) be 0.140ml, thus the deviation factors of trying to achieve gas is 0.984;

6. with vacuum pump, find time the first fill out sand tube to vacuum state, then with pump 12, the rock gas of intermediate receptacle is full of to the first fill out sand tube, open the valve between the first fill out sand tube and the second fill out sand tube, make the first fill out sand tube and the second fill out sand tube keep UNICOM's state, and the equalized pressure P during by pressure sensor monitoring the first fill out sand tube and the series connection of the second fill out sand tube ₂for 32.40MPa; Open the valve between the second fill out sand tube and the 3rd fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube and the series connection of the 3rd fill out sand tube ₃for 25.10MPa, open the valve between the 3rd fill out sand tube and the 4th fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube, the 3rd fill out sand tube and the series connection of the 4th fill out sand tube ₄for 17.33MPa, open the valve between the 4th fill out sand tube and the 5th fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube, the 3rd fill out sand tube, the 4th fill out sand tube and the series connection of the 5th fill out sand tube ₅for 11.86MPa;

7. in PVT test cell, remaining gas is done to volumetric expansion experiment, obtain pressure and be respectively P ₂, P ₃, P ₄and P ₅time rock gas volume V ₂for 35.320ml, V ₃for 48.295ml, V ₄for 71.865ml, V ₅for 102.685ml, thereby obtain considering porous medium and do not consider the deviation factors of rock gas under porous medium (PVT test cell) high-temperature and high-pressure conditions, the results are shown in Table 1 and Fig. 2.

Table 1 is considered porous medium and is not considered the rock gas deviation factors contrast table of porous medium

Pressure (MPa)	Do not consider porous medium	Consider porous medium
			42.34	0.984	0.984
32.40	0.914	0.890
			25.10	0.863	0.847
17.33	0.840	0.830
			11.86	0.859	0.842

Claims (2)

1. the determinator of rock gas deviation factors in a porous medium, mainly by porous medium system, data acquisition and processing system, PVT test cell (10), intermediate receptacle (14), gasometer (13), baking oven (15) forms, it is characterized in that, described porous medium system is by the first fill out sand tube (1), the second fill out sand tube (2), the 3rd fill out sand tube (3), the 4th fill out sand tube (4), the 5th fill out sand tube (5) is in series, described porous medium system is connected with intermediate receptacle (14) with PVT test cell (10) respectively, described PVT test cell (10) and intermediate receptacle (14) are connected with respectively pump one (11), pump two (12), described porous medium system is placed in baking oven (15) and is connected gasometer (13) with PVT test cell, described data acquisition and processing system comprises temperature sensor (9), pressure transducer (7) and computing machine (8), and described porous medium system is connected with computing machine (8) by temperature sensor (9), pressure transducer (7), between the fill out sand tube of described porous medium system, between porous medium system and PVT test cell, between intermediate receptacle, all have a valve (6).

2. utilize device as claimed in claim 1 to measure the method for rock gas deviation factors in porous medium, comprise the following steps successively:

(1) silica sand of different meshes is filled into respectively in 5 fill out sand tube;

(2) at P ₀=0.1MPa, T ₀at=20 ℃, with pump two (12), note N ₂measure successively every fill out sand tube volume of voids and be respectively V _k1, V _k2, V _k3, V _k4, V _k5, between fill out sand tube Bonding pressure sensor, the volume of pipeline is V _c, then discharge N ₂and find time fill out sand tube and pipeline to vacuum state with vacuum pump;

(3) by computing machine, the Temperature Setting of baking oven is become to the formation temperature T of reservoir and is warming up to formation temperature T;

(4) with pump two (12), the rock gas of intermediate receptacle is full of to the first fill out sand tube, by the pressure in pressure sensor monitoring the first fill out sand tube, when pressure equilibrium, writes down the pressure P in the first fill out sand tube now ₁;

(5) will proceed in PVT test cell through the first fill out sand tube absorption a part of rock gas later, with pump one (11), regulating the pressure of rock gas in PVT test cell is P ₁, obtain rock gas at T, P ₁volume V under condition ₁₁, maintenance pressure is P ₁, the rock gas part in PVT test cell is discharged in gasometer, measure rock gas at P ₀=0.1MPa, T ₀volume V at=20 ℃ ₀, then read the rock gas volume V in PVT test cell after exhaust ₁₂, obtain rock gas at T, P ₁volume change value V under condition ₁=V ₁₁-V ₁₂thereby, obtain the deviation factors of gas in PVT test cell

(6) with vacuum pump, find time the first fill out sand tube to vacuum state, then use pump two (12) that the rock gas of intermediate receptacle is full of to the first fill out sand tube, open the valve between the first fill out sand tube and the second fill out sand tube, make the first fill out sand tube and the second fill out sand tube keep UNICOM's state, and the equalized pressure P during by pressure sensor monitoring the first fill out sand tube and the series connection of the second fill out sand tube ₂;

(7) open the valve between the second fill out sand tube and the 3rd fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube and the series connection of the 3rd fill out sand tube ₃, open the valve between the 3rd fill out sand tube and the 4th fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube, the 3rd fill out sand tube and the series connection of the 4th fill out sand tube ₄, open the valve between the 4th fill out sand tube and the 5th fill out sand tube, the equalized pressure P while monitoring the first fill out sand tube, the second fill out sand tube, the 3rd fill out sand tube, the 4th fill out sand tube and the series connection of the 5th fill out sand tube ₅;

(8) in PVT test cell, remaining gas is done to volumetric expansion experiment, obtain pressure and be respectively P ₂, P ₃, P ₄and P ₅time rock gas volume V ₂, V ₃, V ₄, V ₅;

(9) utilize following formula to obtain the deviation factors Z ' of rock gas in porous medium ₁:

The deviation factors of the 1st spot pressure: Z ' ₁=Z ₁

2nd, the deviation factors of 3,4,5 spot pressures:

V′ ₁＝V _c+V _K1

V′ ₂＝V _c+V _K1+V _K2

${V_i}^{\&prime;}=V_c+V_{K1}+\underset{i=2}{\overset{5}{\mathrm{\&Sigma;}}}{V}_{\mathrm{Ki}}.$

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