CN104316449A

CN104316449A - Experimental method and experimental device for determinating volcanic gas-water relative permeability

Info

Publication number: CN104316449A
Application number: CN201410620541.4A
Authority: CN
Inventors: 潘一; 徐子健; 杨双春
Original assignee: Liaoning Shihua University
Current assignee: Liaoning Shihua University
Priority date: 2014-11-05
Filing date: 2014-11-05
Publication date: 2015-01-28

Abstract

The invention relates to an experimental method and an experimental device for measuring the relative permeability of volcanic rock gas and water. Through the experimental steps of rock core preparation, rock sample gas permeability and porosity measurement, application of confining pressure and rock sample gas flooding water, the non- The relative permeability curve of the volcanic rock core was measured when the gas saturation increased and the water saturation decreased by the steady-state method.

Description

An experimental method and experimental device for measuring the relative permeability of volcanic rock gas and water

技术领域technical field

本发明涉及一种测定渗透率的实验方法，尤其涉及一种用于测定火山岩气、水相对渗透率的实验方法及实验装置。The invention relates to an experimental method for measuring permeability, in particular to an experimental method and an experimental device for measuring the relative permeability of volcanic rock gas and water.

背景技术Background technique

火山岩储层属于特低渗透气藏，其储集空间以孔隙为主，但与常规特低渗透储层相比，火山岩通常具有较多的气孔、裂缝发育，因此其火山岩气藏具有较高的商业开采价值。近年来，我国相继开发多处火山岩气藏，并取得一定的经济效益。Volcanic rock reservoirs are ultra-low permeability gas reservoirs, and their storage space is dominated by pores. However, compared with conventional ultra-low permeability reservoirs, volcanic rocks usually have more pores and fractures, so their volcanic rock gas reservoirs have a higher commercial mining value. In recent years, my country has successively developed many volcanic gas reservoirs and achieved certain economic benefits.

气、液相对渗透率曲线为气藏开发动态分析及数值模拟中的重要参考资料，该曲线通常用气藏的真实岩心在实验室中用稳定法测试而获得，而对于火山岩储层，由于其内部的溶洞孔隙结构，两相流体混相注入时易产生突进现象，造成混相，导致测量结果与实际存在较大偏差。由于火山岩样品的特低渗透率，同时驱替压差须小于围压，因此围压大小要适当：若围压过小，驱替压差也将过小，则驱替速度极慢，且易产生水锁现象，并将影响出口流体流量；若驱替压差过大，则将使岩样内微裂缝堵塞，甚至造成岩样断裂。因此应在合适范围内尽可能增大围压以保证有足够的空间调节驱替压差。The relative permeability curve of gas and liquid is an important reference in the dynamic analysis and numerical simulation of gas reservoir development. The curve is usually obtained by testing the real core of the gas reservoir in the laboratory with the stability method. For volcanic rock reservoirs, due to its In the pore structure of the karst cave, when two-phase fluids are injected in mixed phases, it is easy to produce a breakthrough phenomenon, resulting in phase miscibility, which leads to a large deviation between the measurement results and the actual situation. Due to the extremely low permeability of volcanic rock samples and the displacement pressure difference must be lower than the confining pressure, the confining pressure should be appropriate: if the confining pressure is too small, the displacement pressure difference will also be too small, and the displacement speed will be extremely slow and easy Water lock phenomenon will occur, which will affect the outlet fluid flow; if the displacement pressure difference is too large, it will block the micro-cracks in the rock sample, and even cause the rock sample to break. Therefore, the confining pressure should be increased as much as possible within a suitable range to ensure that there is enough space to adjust the displacement pressure difference.

发明内容Contents of the invention

针对上述问题，本发明提出一种用于测定火山岩气、水相对渗透率的实验方法,解决了现有技术中对火山岩气、水相对渗透率测量不够精确的问题。In view of the above problems, the present invention proposes an experimental method for measuring relative permeability of volcanic rock gas and water, which solves the problem of inaccurate measurement of relative permeability of volcanic rock gas and water in the prior art.

本发明的另一目的在于提供一种用于测定火山岩气、水相对渗透率的实验装置。Another object of the present invention is to provide an experimental device for measuring the relative permeability of volcanic rock gas and water.

本发明实验方法包括如下步骤：Experimental method of the present invention comprises the steps:

步骤1，岩心制备：取火山岩岩心，岩心钻取后用聚乙烯膜包好密封；Step 1, core preparation: take the volcanic rock core, wrap and seal it with polyethylene film after the core is drilled;

步骤2，岩样气测渗透率及孔隙度：岩样在90℃烘干4小时后每半小时称重一次，直至连续两次质量变化的相对误差小于5％时，记录此时岩样质量；将岩样放入夹持器中，使用氮气注入，记录驱替压差、出气量，计算岩样气测渗透率；将岩心放入抽真空饱和装置内，将岩心饱和已抽真空的地层水，并称重测量，从而计算出岩样的孔隙体积及有效孔隙度；Step 2, gas permeability and porosity of the rock sample: After drying the rock sample at 90°C for 4 hours, weigh it every half hour until the relative error of two consecutive mass changes is less than 5%, record the mass of the rock sample at this time ; Put the rock sample into the holder, inject nitrogen gas, record the displacement pressure difference and gas output, and calculate the gas permeability of the rock sample; put the rock core into the vacuum saturation device, and saturate the rock core in the vacuumed formation Water, and weighed to measure, so as to calculate the pore volume and effective porosity of the rock sample;

步骤3，施加围压：将饱和模拟底层水后的岩样装入岩心夹持器，利用围压泵给岩心夹持器加围压，围压的取值应在地层破坏压力与启动压力之间；Step 3, apply confining pressure: put the rock sample saturated with simulated bottom water into the core holder, and use the confining pressure pump to add confining pressure to the core holder. The value of the confining pressure should be between the formation failure pressure and the starting pressure. between;

步骤4，岩样气驱水实验：打开气体注入装置的调压阀，给岩心夹持器提上游压力，并在给定的上游压力下进行气驱水；初始压差必须保证即能克服末端效应又不产生紊流；记录各个时刻的驱替时间、驱替压差、累计流体产量、累计产水量和初始见气点，并将数据填入原始数据表中；气驱水达到束缚水状态并进行气测渗透率后结束实验；Step 4, rock sample gas flooding water experiment: open the pressure regulating valve of the gas injection device, put upstream pressure on the core holder, and carry out gas flooding water under a given upstream pressure; the initial pressure difference must be guaranteed to overcome the end The effect does not produce turbulent flow; record the displacement time, displacement pressure difference, cumulative fluid production, cumulative water production and initial gas breakthrough point at each moment, and fill the data into the original data table; the gas drive water reaches the state of irreducible water And end the experiment after performing gas permeability measurement;

气、水相对渗透率的计算公式为：The calculation formula of gas and water relative permeability is:

${K K}_{rg r g} = = \frac{{q q}_{gi gi}}{{q q}_{g g}} - - - - - - ((1010))$

$\frac{{K K}_{rg r g}}{{K K}_{rw rw}} = = \frac{{f f}_{g g}}{{f f}_{w w}} \cdot &Center Dot; \frac{{μ μ}_{g g}}{{μ μ}_{w w}} - - - - - - ((1111))$

式中：In the formula:

${q q}_{gi gi} = = \frac{Δ Δ {V V}_{gi gi}}{Δt Δt} - - - - - - ((1212))$

${q q}_{g g} = = \frac{KA KA}{{μ μ}_{g g}} \cdot &Center Dot; Δp Δp - - - - - - ((1313))$

${f f}_{g g} = = \frac{Δ Δ {V V}_{gi gi}}{Δ Δ {V V}_{i i}} - - - - - - ((1414))$

${f f}_{w w} = = \frac{Δ Δ {V V}_{wi wi}}{Δ Δ {V V}_{i i}} - - - - - - ((1515))$

其中：in:

K_rg———气体相对渗透率，小数；K _rg —— gas relative permeability, decimal;

K_rw——液体相对渗透率，小数；K _rw —— relative permeability of liquid, decimal;

q_gi——两相流动时的气体流量，mL/sq _gi ——gas flow in two-phase flow, mL/s

q_g——单相流动时的气体流量，mL/sq _g ——gas flow in single-phase flow, mL/s

V_w——累计出口水量，mL；V _w —— cumulative outlet water volume, mL;

ΔV_gi——大气压力下测得某一时间间隔的气增量，mL；ΔV _gi — gas gain measured at a certain time interval under atmospheric pressure, mL;

ΔV_wi——大气压力下测得某一时间间隔的水增量，mL；ΔV _wi — water increment measured at a certain time interval under atmospheric pressure, mL;

Δp——驱替压差，MPa；Δp——displacement differential pressure, MPa;

A——截面积，m²；A——cross-sectional area, m ² ;

Δt——时间间隔，s；Δt——time interval, s;

K——气测绝对渗透，μm² K——Absolute gas permeability, μm ²

ΔV——大气压力下测得某一时间间隔的流体总增量，mL；ΔV——the total increment of fluid measured at a certain time interval under atmospheric pressure, mL;

f_g——含气率，小数；f _g ——gas fraction, decimal;

f_w——含水率，小数；f _w —— moisture content, decimal;

μ_g——注入气体粘度；mPa.s；μ _g —viscosity of injected gas; mPa.s;

μ_w——饱和岩样的模拟地层水的粘度；mPa.s。μ _w —viscosity of simulated formation water of saturated rock sample; mPa.s.

所述的步骤1中，岩心钻取直径2.50cm，长度不得低于直径的2倍，不多于直径的5倍。In the step 1, the core is drilled with a diameter of 2.50 cm, and the length shall not be less than 2 times of the diameter, and shall not be more than 5 times of the diameter.

本发明的实验装置结构如下：Experimental device structure of the present invention is as follows:

手摇泵连接岩心夹持器，手摇泵与岩心夹持器之间设有压力表和围压两通阀；气瓶连通气体注入装置的一侧，气体加湿器的另一侧连接岩心夹持器，气瓶与气体加湿器之间设有调压阀，气体加湿器与岩心夹持器之间设有压力表和两通阀；岩心夹持器连接气液分离器的输入端，气液分离器的输出端连接微量气体流量计和量筒，量筒连接电子天平。The hand pump is connected to the core holder, and a pressure gauge and a two-way valve for confining pressure are installed between the hand pump and the core holder; the gas cylinder is connected to one side of the gas injection device, and the other side of the gas humidifier is connected to the core holder There is a pressure regulating valve between the gas cylinder and the gas humidifier, a pressure gauge and a two-way valve between the gas humidifier and the core holder; the core holder is connected to the input end of the gas-liquid separator, and the gas The output end of the liquid separator is connected with a micro gas flow meter and a graduated cylinder, and the graduated cylinder is connected with an electronic balance.

所述的气体注入装置为气体加湿器。The gas injection device is a gas humidifier.

所述的岩心夹持器通过带刻度的微毛细管连接气液分离器。The core holder is connected to the gas-liquid separator through a graduated microcapillary.

本发明的优点效果如下：The advantages and effects of the present invention are as follows:

使用简单方便，同时能准确的测量火山岩气、水相对渗透率曲线。该方法对低渗气藏开发的实验研究具有重要意义。It is simple and convenient to use, and can accurately measure the relative permeability curves of volcanic rock gas and water. This method is of great significance to the experimental research on the development of low-permeability gas reservoirs.

附图说明Description of drawings

下面结合附图和实施例对本发明进一步说明。The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

图1为一种用于测定火山岩气、水相对渗透率的实验装置结构示意图。Figure 1 is a schematic structural diagram of an experimental device for measuring the relative permeability of volcanic rock gas and water.

图中，1、气瓶，2、调压阀，3、气体加湿器，4、压力表，5、两通阀，6、岩心夹持器，7、手摇泵，8、压力表，9、围压两通阀，10、带刻度的微毛细管，11、气液分离器，12、微量气体流量计，13、量筒，14、电子天平。In the figure, 1. gas cylinder, 2. pressure regulating valve, 3. gas humidifier, 4. pressure gauge, 5. two-way valve, 6. core holder, 7. hand pump, 8. pressure gauge, 9 1. Confining pressure two-way valve, 10. Microcapillary with scale, 11. Gas-liquid separator, 12. Micro gas flowmeter, 13. Graduated cylinder, 14. Electronic balance.

具体实施方式Detailed ways

实施例Example

参照附图1，本发明实验装置结构为，围压手摇泵7连接岩心夹持器6，手摇泵7与岩心夹持器6之间设有压力表8和围压两通阀9；气瓶1连通气体加湿器3的一侧，气体加湿器3的另一侧连接岩心夹持器6，气瓶1与气体加湿器3之间设有调压阀2，气体加湿器3与岩心夹持器6之间设有压力表4和两通阀5；岩心夹持器6通过带刻度的微毛细管10连接气液分离器11的输入端，气液分离器11的输出端连接微量气体流量计12和量筒13，量筒13连接高精度电子天平14。Referring to accompanying drawing 1, the structure of the experimental device of the present invention is that the confining pressure hand pump 7 is connected to the rock core holder 6, and a pressure gauge 8 and a confining pressure two-way valve 9 are arranged between the hand pump 7 and the rock core holder 6; The gas cylinder 1 is connected to one side of the gas humidifier 3, and the other side of the gas humidifier 3 is connected to the core holder 6. There is a pressure regulating valve 2 between the gas cylinder 1 and the gas humidifier 3, and the gas humidifier 3 and the core A pressure gauge 4 and a two-way valve 5 are arranged between the holders 6; the core holder 6 is connected to the input end of the gas-liquid separator 11 through a graduated microcapillary 10, and the output end of the gas-liquid separator 11 is connected to a trace gas The flowmeter 12 and the measuring cylinder 13, the measuring cylinder 13 is connected with a high precision electronic balance 14.

使用时，手摇泵7向岩心夹持器6提供围压，通过压力表8读出，并可在关闭围压两通阀9以保持围压。气体从气瓶1流出，流经调压阀2，通过气体加湿器3、两通阀5注入岩心夹持器6，压力表4可读出入口压力。气体与液体通过岩心后从带刻度的微毛细管10流出，流入气液分离器11，气体流入微量气体流量计12，液体流入量筒13，同时，使用高精度电子天平14对进行液体称重。When in use, the hand pump 7 provides confining pressure to the core holder 6, which is read by the pressure gauge 8, and the confining pressure two-way valve 9 can be closed to maintain the confining pressure. The gas flows out from the gas cylinder 1, flows through the pressure regulating valve 2, and is injected into the core holder 6 through the gas humidifier 3 and the two-way valve 5, and the pressure gauge 4 can read the inlet pressure. The gas and liquid flow out from the graduated microcapillary 10 after passing through the rock core, and flow into the gas-liquid separator 11, the gas flows into the micro gas flow meter 12, and the liquid flows into the measuring cylinder 13. At the same time, the high-precision electronic balance 14 is used to weigh the liquid.

步骤1，岩心制备：取火山岩岩心，钻取直径2.50cm，长度不得低于直径的2倍，钻取后用聚乙烯膜包好密封；Step 1, core preparation: take the volcanic rock core, drill it with a diameter of 2.50 cm, and the length should not be less than twice the diameter, and wrap it with a polyethylene film to seal after drilling;

步骤3，施加围压：将饱和模拟底层水后的岩样装入岩心夹持器，利用围压泵给岩心夹持器加围压，围压取值应低于地层破坏压力，对于特低渗透岩样，其驱替压差须高于启动压力，故围压的取值应在地层破坏压力与启动压力之间取值；Step 3, apply confining pressure: put the rock sample saturated with simulated bottom water into the core holder, and use the confining pressure pump to add confining pressure to the core holder. The value of the confining pressure should be lower than the formation failure pressure. For permeable rock samples, the displacement pressure difference must be higher than the start-up pressure, so the value of the confining pressure should be taken between the formation failure pressure and the start-up pressure;

步骤4，岩样气驱水实验：打开气体注入装置的调压阀，给岩心夹持器提上游压力，并在给定的上游压力(如：5MPa)下进行气驱水；初始压差必须保证即能克服末端效应又不产生紊流；记录各个时刻的驱替时间、驱替压差、累计流体产量、累计产水量和初始见气点，并将数据填入原始数据表中；气驱水达到束缚水状态并进行气测渗透率后结束实验；Step 4, rock sample gas flooding water experiment: open the pressure regulating valve of the gas injection device, put upstream pressure on the core holder, and carry out gas flooding water under a given upstream pressure (such as: 5MPa); the initial pressure difference must be Ensure that the terminal effect can be overcome without generating turbulent flow; record the displacement time, displacement pressure difference, cumulative fluid production, cumulative water production and initial gas breakthrough point at each moment, and fill the data into the original data table; The water reaches the state of bound water and the gas permeability is measured to end the experiment;

${K K}_{rg r g} = = \frac{{q q}_{gi gi}}{{q q}_{g g}} - - - - - - ((1010))$

式中：In the formula:

${q q}_{gi gi} = = \frac{Δ Δ {V V}_{gi gi}}{Δt Δt} - - - - - - ((1212))$

${q q}_{g g} = = \frac{KA KA}{{μ μ}_{g g}} \cdot \cdot Δp Δp - - - - - - ((1313))$

其中：in:

Δp——驱替压差，MPa；Δp—displacement differential pressure, MPa;

A——截面积，m²；A——cross-sectional area, m ² ;

Δt——时间间隔，s；Δt——time interval, s;

K——气测绝对渗透，μm² K——Absolute gas permeability, μm ²

f_g——含气率，小数；f _g ——gas fraction, decimal;

f_w——含水率，小数；f _w —— moisture content, decimal;

Claims

1. an experimental method for measuring volcanic rock gas, water relative permeability, is characterized in that comprising the steps:

Step 1, core preparation: take the volcanic rock core, wrap and seal it with polyethylene film after the core is drilled;

Step 2, Permeability and porosity of the rock sample by gas measurement: the rock sample is weighed every half an hour after drying at 90°C for 4 hours, until the relative error of two consecutive mass changes is less than 5%, record the mass of the rock sample at this time ; Put the rock sample into the holder, inject nitrogen gas, record the displacement pressure difference and gas output, and calculate the gas permeability of the rock sample; put the rock core into the vacuum saturation device, and saturate the rock core in the vacuumed formation Water, and weighed to measure, so as to calculate the pore volume and effective porosity of the rock sample;

Step 3, apply confining pressure: put the rock sample saturated with simulated bottom water into the core holder, and use the confining pressure pump to add confining pressure to the core holder. The value of the confining pressure should be between the formation failure pressure and the starting pressure. between;

Step 4, rock sample gas flooding water experiment: open the pressure regulating valve of the gas injection device, put upstream pressure on the core holder, and carry out gas flooding water under a given upstream pressure; the initial pressure difference must be guaranteed to overcome the end The effect does not produce turbulent flow; record the displacement time, displacement pressure difference, cumulative fluid production, cumulative water production and initial gas breakthrough point at each moment, and fill the data into the original data table; gas drive water reaches the state of irreducible water And end the experiment after gas permeability measurement;

The calculation formula of gas and water relative permeability is:

{K K}_{rg r g} = = \frac{{q q}_{gi gi}}{{q q}_{g g}} - - - - - - ((1010))

\frac{{K K}_{rg r g}}{{K K}_{rw rw}} = = \frac{{f f}_{g g}}{{f f}_{w w}} \cdot \cdot \frac{{μ μ}_{g g}}{{μ μ}_{w w}} - - - - - - ((1111))

In the formula:

{q q}_{gi gi} = = \frac{{ΔV ΔV}_{gi gi}}{Δt Δt} - - - - - - ((1212))

{q q}_{g g} = = \frac{KA KA}{{μ μ}_{g g}} Δp Δp - - - - - - ((1313))

{f f}_{g g} = = \frac{{ΔV ΔV}_{gi gi}}{{ΔV ΔV}_{i i}} - - - - - - ((1414))

{f f}_{w w} = = \frac{{ΔV ΔV}_{wi wi}}{{ΔV ΔV}_{i i}} - - - - - - ((1515))

in:

K _rg —— gas relative permeability, decimal;

K _rw —— relative permeability of liquid, decimal;

q _gi ——gas flow in two-phase flow, mL/s

q _g ——gas flow in single-phase flow, mL/s

V _w —— cumulative outlet water volume, mL;

ΔV _gi — gas gain measured at a certain time interval under atmospheric pressure, mL;

ΔV _wi — water increment measured at a certain time interval under atmospheric pressure, mL;

Δp—displacement differential pressure, MPa;

A——cross-sectional area, m ² ;

Δt——time interval, s;

K——Absolute gas permeability, μm ²

ΔV——the total increment of fluid measured at a certain time interval under atmospheric pressure, mL;

f _g ——gas fraction, decimal;

f _w —— moisture content, decimal;

μ _g —viscosity of injected gas; mPa.s;

μ _w —viscosity of simulated formation water of saturated rock sample; mPa.s.

2. A kind of experimental method for measuring volcanic rock gas, water relative permeability according to claim 1, it is characterized in that in described step 1, rock core is drilled diameter 2.50cm, and length must not be less than 2 times of diameter , not more than 5 times the diameter.

3. A kind of experimental device for measuring volcanic rock gas, water relative permeability experimental method according to claim 1, is characterized in that structure is as follows: hand pump (7) connects rock core holder (6), hand-operated A pressure gauge (8) and a confining pressure two-way valve (9) are arranged between the pump (7) and the core holder (6); the gas cylinder (1) is connected to one side of the gas injection device, and the gas humidifier (3) The other side is connected to the core holder (6), and a pressure regulating valve (2) is arranged between the gas cylinder (1) and the gas humidifier (3), and the gas humidifier (3) and the core holder (6) A pressure gauge (4) and a two-way valve (5) are arranged between them; the core holder (6) is connected to the input end of the gas-liquid separator (11), and the output end of the gas-liquid separator (11) is connected to the trace gas flow rate Meter (12) and graduated cylinder (13), graduated cylinder (13) is connected electronic balance (14).

4. A kind of experimental device for measuring volcanic rock gas, water relative permeability experimental method according to claim 3, is characterized in that described gas injection device is a gas humidifier (3).

5. a kind of experimental device for measuring volcanic rock gas, water relative permeability experimental method according to claim 3 is characterized in that described rock core holder (6) is connected by the microcapillary tube (10) with scale Gas-liquid separator (11).