阅读说明：本技术 一种基于光场重构的井下液体分析系统及方法 (Underground liquid analysis system and method based on light field reconstruction ) 是由 杨琦 许一力 于 2020-08-03 设计创作，主要内容包括：一种基于光场重构的井下液体分析系统,包括一宽光谱光源,其波长范围涵盖400纳米至2200纳米的可见光和近红外波段；第一光场整形组件,用于将光源发射的宽光谱整形为平行光；一液体检测通道,液体检测通道包括平行光可直进、直出的进光口与出光口；第二光场整形组件,用于将经过液体检测通道的平行光在空间上进行频率分离；一光接收组件,所述光接收组件用于探测分光后特定波长的光信号,本发明还提供了一种基于光场重构的井下液体分析方法。与现有技术相比,本发明摒弃了传统分光强的方式,大幅提高了载有信息光线的利用效率,提高了数据分析的精度；同时工作时不需要外加机械部件,可实现全固态制作,更加适用于适应井下的高温、高压及高振动环境。(A downhole liquid analysis system based on optical field reconstruction comprises a broad spectrum light source, a light source and a control unit, wherein the wavelength range of the broad spectrum light source covers visible light and near infrared wave bands of 400-2200 nanometers; the first light field shaping component is used for shaping the broad spectrum emitted by the light source into parallel light; the liquid detection channel comprises a light inlet and a light outlet, and the parallel light can enter and exit directly; the second light field shaping component is used for carrying out frequency separation on the parallel light passing through the liquid detection channel on the space; the invention further provides a downhole liquid analysis method based on light field reconstruction. Compared with the prior art, the method abandons the traditional light splitting mode, greatly improves the utilization efficiency of the light carrying information, and improves the precision of data analysis; meanwhile, mechanical parts are not needed to be added during working, all-solid-state manufacturing can be realized, and the method is more suitable for adapting to underground high-temperature, high-pressure and high-vibration environments.)

1. A downhole fluid analysis system based on optical field reconstruction, comprising:

the wide-spectrum light source comprises a frequency band which can be absorbed by a target component in liquid, and the wavelength range of the wide-spectrum light source covers visible light and near infrared bands of 400-2200 nanometers;

the first light field shaping component is used for shaping the broad spectrum emitted by the light source into parallel light;

the liquid detection channel comprises a light inlet and a light outlet, parallel light can enter and exit directly, and a liquid inlet and outlet channel is arranged between the light inlet and the light outlet;

the second light field shaping component is used for separating the parallel light passing through the liquid detection channel according to frequency in space, and comprises a blazed grating and a micro lens;

and the light receiving component is used for detecting the optical signal with the specific wavelength after the light splitting.

2. The downhole fluid analysis system based on optical field reconstruction as claimed in claim 1, wherein the fluid detection channel is a section of the oil transmission pipeline body, and the section is provided with a transparent light inlet and a transparent light outlet which are opposite to each other.

3. The downhole fluid analysis system based on optical field reconstruction as claimed in claim 1, wherein the fluid detection channel is an independent channel, the independent channel is detachably connected with the oil transmission pipeline body, and the independent channel is adopted to pretreat the fluid in advance.

4. The downhole fluid analysis system based on light field reconstruction as claimed in claim 2 or 3, wherein the light receiving assembly comprises a fiber set, a filter and a detector array, the fiber set is connected with the filter and correspondingly connected with the detector array, and the filter and the detector array can be manufactured integrally.

5. A downhole fluid analysis method based on optical field reconstruction, using an analysis system according to claims 1-4, comprising the steps of;

s1, the wide spectrum light source emits light beams with the wavelength range covering 400 nm to 2200 nm wave bands;

s2, shaping the light beam into parallel emergent light by the first light field shaping assembly, and expanding an emergent surface;

s3, enabling parallel light to enter liquid in the liquid detection channel through the light inlet, enabling different target components in the liquid to absorb light rays with corresponding frequencies, and enabling the absorbed light rays to be emitted from the light outlet;

s4, separating the light rays with different frequencies on space by the second light field shaping component, and emitting the light rays with different frequencies along different directions;

and S5, light is split by the second light field shaping component and enters the light receiving component, the light receiving component converts the light with specific frequency into an electric signal, and the electric signal generated by conversion is output to an external signal processing system for comparison and analysis, so that a liquid component analysis result can be obtained.

6. The method for downhole fluid analysis based on optical field reconstruction of claim 5 wherein said second optical field shaping component is fabricated by LSI process.

7. The downhole fluid analysis method based on light field reconstruction as claimed in claim 5, wherein said step S4 can split light of a plurality of different frequencies.

Technical Field

The invention relates to the technical field of petroleum detection, in particular to an underground liquid analysis system and method based on light field reconstruction.

Background

In the process of oil exploration, real-time liquid component analysis needs to be carried out on the extracted liquid components underground. Real-time downhole fluid composition analysis provides mainly the following advantages:

1) providing liquid composition information in time to help a field engineer to quickly make a survey plan;

2) the damage and the deterioration of the liquid in the transferring process are avoided;

3) the liquid can have phase change in different pressure and temperature environments, so that the composition on site is more valuable;

4) synchronized with other information in the probing process (e.g., temperature, resistivity, etc.).

Due to the advantages, the real-time downhole liquid component analysis is widely applied to the field of oil detection, including oil and gas reservoir liquid property detection, oil and gas reservoir boundary analysis, oil and gas component grade determination, development and completion scheme formulation according to liquid corrosivity and scaling, sample purity and single-phase property guarantee, and reservoir oil and gas proportion determination.

Currently, the conventional real-time downhole fluid composition analysis methods generally include the following two methods:

a first conventional real-time downhole fluid composition analysis comprises the steps of:

1) a window is arranged in the petroleum transmission pipeline, and all incident light uniformly irradiates the liquid section to be analyzed;

2) light of a particular wavelength is absorbed by the corresponding component in the liquid as the incident light passes through the liquid. For example, the main absorption peak of water is around 1500 nm, the main absorption peak of carbon dioxide is around 2000 nm, and the middle oil has an absorption peak … … at 1700 nm;

3) then the emergent light is split by the optical fiber array, and the optical fiber of each channel passes through a part of the emergent light; for example in a 20-channel fiber array, 1/20 for all outgoing light to pass through in each channel;

4) the light rays emerging from the optical fiber group pass through the optical filter to pass light of each specific wavelength (for the corresponding detection liquid component);

5) light of a specific wavelength passing through the optical filter enters an array of spectrometers, each spectrometer analyzing the light for which it is directed;

6) the content of each component in the liquid can be calculated according to the intensity detected by each spectrometer.

A significant limitation of this conventional approach is that only a portion of the light passes through each set of fiber channels, typically below 1/10 of the total amount of light flux. A large amount of light carrying information is wasted. This not only puts higher demands on the accuracy of the spectrometer, but also further limits the signal-to-noise ratio of the effective signal.

The second conventional real-time downhole liquid composition analysis method is different from the first one in that light is not split by the optical fiber array after passing through the liquid, but is totally irradiated onto the optical chip. Each optical chip is used to analyze a different component. In order to analyze a plurality of components, different optical chips are moved to the light exit window in turn by a mechanical rotation mode. This analysis allows the full use of the information-containing light, but a mechanical operation has to be used. This makes it difficult to ensure reliability in a high vibration environment downhole, and thus also makes it difficult to improve yield. .

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an underground liquid analysis system and method based on light field reconstruction, which comprises the following steps:

the technical scheme of the invention is realized as follows:

a downhole fluid analysis system based on optical field reconstruction, comprising:

the wide-spectrum light source comprises a frequency band which can be absorbed by a target component in liquid, and the wavelength range of the wide-spectrum light source covers visible light and near infrared bands of 400-2200 nanometers;

the first light field shaping component is used for shaping the broad spectrum emitted by the light source into parallel light;

the liquid detection channel comprises a light inlet and a light outlet, parallel light can enter and exit directly, and a liquid inlet and outlet channel is arranged between the light inlet and the light outlet;

the second light field shaping component is used for separating the parallel light passing through the liquid detection channel according to frequency in space, and comprises a blazed grating and a micro lens;

and the light receiving component is used for detecting the optical signal with the specific wavelength after the light splitting.

Preferably, the liquid detection channel is a section of the petroleum transmission pipeline body, and the section is provided with a transparent light inlet and a transparent light outlet which are opposite to each other.

Preferably, the liquid detection channel is an independent channel, the independent channel is detachably connected with the oil transmission pipeline body, and liquid can be pretreated in advance by adopting the independent channel.

Preferably, the light receiving assembly comprises an optical fiber group, an optical filter and a detector array, the optical fiber group is connected with the optical filter and then correspondingly connected with the detector array, and the optical filter and the detector array can be manufactured integrally.

The invention also provides a downhole liquid analysis method based on the light field reconstruction, which comprises the following steps;

s1, the wide spectrum light source emits light beams with the wavelength range covering 400 nm to 2200 nm wave bands;

s2, shaping the light beam into parallel emergent light by the first light field shaping assembly, and expanding an emergent surface;

s3, enabling parallel light to enter liquid in the liquid detection channel through the light inlet, enabling different target components in the liquid to absorb light rays with corresponding frequencies, and enabling the absorbed light rays to be emitted from the light outlet;

s4, separating the light rays with different frequencies on space by the second light field shaping component, and emitting the light rays with different frequencies along different directions;

and S5, light is split by the second light field shaping component and enters the light receiving component, the light receiving component converts the light with specific frequency into an electric signal, and the electric signal generated by conversion is output to an external signal processing system for comparison and analysis, so that a liquid component analysis result can be obtained.

Preferably, the second optical field shaping component is fabricated by an LSI process.

Preferably, the step S4 may split light of a plurality of different frequencies.

Compared with the prior art, the invention has the following beneficial effects:

according to the underground liquid analysis system and method based on the light field reconstruction, after light rays are emitted from liquid to be detected, the light rays are separated by the light field shaping chip according to different frequencies, the separated light rays respectively enter the specific optical filter and the photoelectric conversion device, and the method enables the light rays with each specific frequency to be concentrated on the corresponding optical filter/receiver in a frequency splitting mode, so that the traditional light intensity splitting mode is abandoned, the utilization efficiency of the light rays with information is greatly improved, and the data analysis precision is improved; meanwhile, during working, different optical chips are driven to move to the light emitting window in turn without adding mechanical parts, so that all-solid-state manufacturing can be realized, and the all-solid-state optical device is more suitable for adapting to underground high-temperature, high-pressure and high-vibration environments.

Drawings

FIG. 1 is a block diagram of a downhole fluid analysis system based on optical field reconstruction in accordance with the present invention;

FIG. 2 is a flow chart of a downhole fluid analysis method based on optical field reconstruction according to the present invention.

In the figure: the system comprises a broad spectrum light source 100, a first light field shaping assembly 200, a liquid detection channel 300, a second light field shaping assembly 400, a light receiving assembly 500, an optical fiber group 510, a filter 520 and a detector array 530.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown.

As shown in fig. 1, a downhole fluid analysis system based on optical field reconstruction includes:

the wide-spectrum light source 100 can be generated by exciting fluorescent powder by laser or is formed by combining a plurality of light sources, the wide-spectrum light source 100 comprises a frequency band which can be absorbed by a target component in liquid, and the wavelength range of the wide-spectrum light source 100 covers visible light and near infrared bands of 400 nanometers to 2200 nanometers;

the first light field shaping component 200 is used for shaping the broad spectrum emitted by the light source into parallel light, and the first light field shaping component 200 can ensure the uniformity of a light field; the action area of the incident light and the liquid can be enlarged, and the absorption effect of the light in the liquid is improved. The first light field shaping component 200 can be a lens or a micro-optical device, the micro-optical device can be manufactured by an LSI process, and in addition, the micro-optical device can also be integrally manufactured with a light source and a window to further improve the anti-vibration strength and reduce the volume of the device;

a liquid detection channel 300, wherein the liquid detection channel 300 comprises a light inlet and a light outlet through which parallel light can directly enter and exit, and a liquid inlet and outlet channel is arranged between the light inlet and the light outlet; parallel light passes through the light inlet (irradiating the detected liquid which is a mixture produced underground and can comprise crude oil components, water, gas, slurry and other impurities, the light with different wavelengths in the liquid is respectively absorbed by specific liquid components so as to carry liquid component information, the absorption peak of the water is mainly 1500 nm, the absorption peak of the carbon dioxide is mainly 2000 nm, the absorption peak of the medium oil is mainly about 1700 nm, the absorption degree of the light is in direct proportion to the concentration of the liquid according to the Beer-Lambert law, therefore, the absorbed light carries the information of the liquid components, and the light is emitted out through a window on the other side after being absorbed by the liquid;

a second light field shaping component 400 for spatially separating the parallel light passing through the liquid detection channel 300 according to frequency, the second light field shaping component 400 comprising a blazed grating and a microlens; both the blazed grating and the microlens can be fabricated by an LSI process to reduce volume and weight to improve reliability in a high vibration environment. The main function is to spatially separate the light with different frequencies, and the light with different frequencies will exit in different directions (with different orders). Each direction (order) will contain a large fraction (> 70%) of the light at its particular frequency, much greater than the intensity of conventional methods (the light essentially needs to be more than 10 beams, then < 10%). In which light of different frequencies is spatially separated. The second optical field shaping module 400 has the functions of frequency division and optical path division. The second optical field shaping module 400 can also be fabricated by an LSI process, which can be effectively integrated on the light outlet and the subsequent light receiving module 500.

A light receiving assembly 500, wherein the light receiving assembly 500 is used for detecting the optical signal with the specific wavelength after the light splitting, the light receiving assembly 500 includes an optical fiber group 510, an optical filter 520 and a detector array 530, the optical fiber group 510 is connected with the optical filter 520 and is further correspondingly connected with the detector array 530; the filters 520 may also be directly integrated with the detector array 530. The detector array 530 is a photoelectric conversion device for a specific wavelength. The electric signal generated by the conversion is output to an external signal processing system. To determine the degree of absorption of the light, the logarithm of the ratio of the incident light intensity to the emergent light intensity is calculated during signal processing. A higher value indicates more absorption at its frequency and a higher content of the corresponding liquid/gas component. The liquid/gas content can be quantitatively calculated after being compared with the value in an external signal processing system.

The liquid detection channel 300 can be a section of the oil transmission pipeline body; the section is provided with a transparent light inlet and a transparent light outlet which are opposite to each other. Or a separate section of the detection dedicated channel. Namely, the liquid detection channel 300 is an independent channel, and the independent channel is detachably connected with the oil transmission pipeline body, so that liquid can be pretreated in advance when the independent channel is adopted.

As shown in FIG. 2, the invention also provides a downhole fluid analysis method based on optical field reconstruction, which comprises the following steps;

s1, the wide spectrum light source 100 emits a light beam with a wavelength ranging from 400 nm to 2200 nm;

s2, the first light field shaping assembly 200 shapes the light beam into parallel emergent light and expands an emergent surface;

s3, enabling the parallel light to enter the liquid in the liquid detection channel 300 through the light inlet, enabling different target components in the liquid to absorb light rays with corresponding frequencies, and enabling the absorbed light rays to be emitted from the light outlet;

s4, the second light field shaping assembly 400 separates the light rays with different frequencies in space, and the light rays with different frequencies are emitted in different directions;

s5, the light beam is split by the second light field shaping module 400 and enters the light receiving module 500, the light receiving module 500 converts the light beam with a specific frequency into an electrical signal, and the electrical signal generated by the conversion is output to an external signal processing system for comparison and analysis, so as to obtain a liquid component analysis result.

The second optical field shaping component 400 is fabricated by an LSI process.

The step S4 can split the light with different frequencies

The step S4 may split light according to ten different wavelength bands.

The invention has the following beneficial effects:

1. the light field shaping assembly is utilized to separate the optical signals carrying the liquid component information in space, the light with the same frequency is intensively incident into the corresponding optical filter/receiver, and the light energy is effectively utilized: in the traditional underground real-time liquid component analysis system, the frequency of an optical signal with information is divided in a final optical filter, the signal with the same frequency is divided into a plurality of parts (more than 10), and a large amount of information is wasted. The information utilization efficiency is 10% or less. The optical signal in the invention is divided and then enters the light receiving component, and the light with each specific frequency is concentrated to the corresponding optical filter/receiver, thus not only improving the utilization efficiency (reaching more than 70 percent), but also effectively reducing the interference of stray light (the signal-to-noise ratio can be improved by more than 10 times).

2. The whole system does not contain mechanical moving parts, and has high reliability in a high-vibration environment underground.

3. The first optical field shaping component and the second optical field shaping component can adopt micro optical devices manufactured by LSI technology, and further realize miniaturization and light weight on the basis of ensuring optical performance. This is very important for high oscillation environments downhole. Meanwhile, the size requirement of the underground oil detection device is met.

4. The second optical field shaping component and the light receiving component can be highly integrated through a wafer-level optical system, and can also be directly packaged and integrated through a module process. This can greatly improve the yield and reduce the labor cost in the assembly process.

5. The first light field shaping component and the second light field shaping component can be a micro lens, a blazed grating element, a diffractive optical element and a micro-nano optical element.

6. The whole system can be further integrated to realize full solidification so as to further improve the signal accuracy and adapt to the underground vibration environment.

According to the underground liquid analysis system and method based on the light field reconstruction, after light rays are emitted from liquid to be detected, the light rays are separated by the light field shaping chip according to different frequencies, the separated light rays respectively enter the specific optical filter and the photoelectric conversion device, and the method enables the light rays with each specific frequency to be concentrated on the corresponding optical filter/receiver in a frequency splitting mode, so that the traditional light intensity splitting mode is abandoned, the utilization efficiency of the light rays with information is greatly improved, and the data analysis precision is improved; meanwhile, during working, different optical chips are driven to move to the light emitting window in turn without adding mechanical parts, so that all-solid-state manufacturing can be realized, and the all-solid-state optical device is more suitable for adapting to underground high-temperature, high-pressure and high-vibration environments.