DE102011086206A1 - Arrangement for determining spectral characteristics of boring fluid under influence of high temperature and mechanical loads at place of occurrence of fluid, has source for polychromatic electromagnetic radiation source and optical unit - Google Patents

Abstract

The arrangement has a source for polychromatic electromagnetic radiation source and an optical unit for directing the electromagnetic radiation to the fluid (9). A grating spectrometer has an original-grating with a grating period aligned on a radiation wavelength in a range from 200 nanometers to 4000 nanometers. The grating is formed as a reflection grating. The grating is placed in a surface of a substrate of an iron-nickel alloy and is placed in a polyetheretherketone material. The grating spectrometer is equipped with a detector, which has one or multiple indium-gallium-arsenic sensors. An independent claim is included for a spectrometer with a boring connecting rod.

Description

The invention relates to an arrangement for determining the spectral properties of borehole fluids in oil production under the influence of high temperature and mechanical stresses at the point of their occurrence in the borehole.

Today crude oil is extracted from layers of earth that were unavailable for technical reasons just a few years ago. There are several known ways of obtaining information about the drilled rock and the expected quality of the oil during exploration, especially from spectrometric investigations. Conventionally, the borehole is drilled in sections or even completely, without taking detailed measurements during drilling.

Nevertheless, in order to be able to evaluate the expected quality of the oil, drilling cores and also crude oil samples are brought to the surface. For this purpose, the drill string has to be pulled out of the borehole in a time- and cost-consuming manner. The spectrometric investigations of the material extracted from the borehole, in particular the evaluation of the absorption bands of various hydrocarbons in the infrared spectral range, make it possible to evaluate the different crude oil qualities. Another disadvantage is that each crude oil sample must be kept in a sample container under the pressure under which it was taken in depth, and thus has to be transported to a place of analysis.

In a further development of the aforementioned procedure, a measuring probe is lowered into the borehole, which is preferably connected via a cable with evaluation devices on the earth's surface. Although this approach provides the ability to power the depth of the probe and ensures fast data transfer, including fast data analysis, it is also important to first pull the drill out of the hole. In addition, there is a risk of damage to the probe, as it is exposed to the high temperatures in the borehole.

In DE 60 2004 012 554 T2 For example, an optical method and an analyzer with respect to a sample container are described. Sample containers including analyzer are lowered into the well after removal of the drill string. Sampling takes place in the depth of the well, and analysis can be done both in-situ in the well and after withdrawing the sample well and analyzer at a dedicated analytical site. In this case, a non-invasive analysis of the sample is carried out by means of the analyzer, without having to open the container or disturb the sample in any other way. The sample container has a window through which light is directed to the sample.

Out US 2007/0171414 A1 a spectral analysis module for a well fluid is known, which is designed as a grating spectrometer with a replica grating, in which the grating pitch is applied to a material from the group of glass, quartz, sapphire, silicon carbide or ceramic. Sampling and sample analysis are done on-site in the well after the drill string has been removed from the wellbore and the analysis module has been lowered.

More recent methods attempt to integrate an analysis device into the first meters of the drill string. This has in comparison to the above procedure not only the advantage that the properties of the drilled rock layers and crude oil can be determined during the drilling process and eliminating the extraction of the drill string deleted, but also the advantage that the used for cooling the drill bit drilling fluid at the same time also the analysis device cools.

Furthermore, this also reduces the cost of taking and analyzing the sample, since the measurement takes place at the high pressures in the field and it is no longer necessary, sample container in which the sample is held under pressure, out of the well and to a Transport analysis site. In addition, it is possible in this way to analyze samples as far as possible without contamination by drilling fluid and thus come to more accurate statements about the quality.

However, in addition to the high temperatures and pressures at depth, the analytical devices required for this purpose are additionally exposed to high mechanical loads due to the accelerations, vibrations and impacts that inevitably occur during drilling.

In this respect, there is a need in the pertinent technical field for analysis devices which permit a spectrometrically wavelength-correct analysis of the crude oil during drilling under the condition of temperatures in the range of 150 ° C. to 200 ° C. and under said mechanical loads.

A spectrometer that meets these extreme requirements is not known in the current state of the art.

On this basis, the object of the invention is to develop a measuring arrangement of the type described above so that even at working temperatures of 150 ° C to 200 ° C and mechanical stresses due to extreme pressures, accelerations, vibrations and shocks spectrometrically wavelength-correct material analysis, especially of crude oil while drilling is possible.

• – eine Quelle für polychromatische elektromagnetische Strahlung,
• – eine Probenkammer mit dem Fluid,
• – optische Mittel zur Ausrichtung der elektromagnetischen Strahlung auf das Fluid, und
• – eine Spektralanalyse-Einrichtung in Form eines Gitterspektrometers, ausgebildet zum Detektieren des Spektrums der vom Fluid transmittierten oder gestreuten elektromagnetischen Strahlung, wobei
• − das Gitterspektrometer ein Original-Gitter mit einer auf Strahlungswellenlängen λ im Bereich von 200 nm bis 4000 nm abgestimmten Gitterperiode aufweist.

This object is achieved with an arrangement for determining spectral properties of a borehole fluid comprising

• - a source of polychromatic electromagnetic radiation,
• A sample chamber with the fluid,
• - Optical means for aligning the electromagnetic radiation to the fluid, and
• A spectral analysis device in the form of a grating spectrometer, designed to detect the spectrum of the electromagnetic radiation transmitted or scattered by the fluid, wherein
• - The grating spectrometer has an original grating with a tuned to radiation wavelengths λ in the range of 200 nm to 4000 nm grating period.

The design of the lattice as an original lattice has the advantage of higher stability of the lattice under the high operating temperatures to which the spectrometer is exposed compared to the use of replica, while in the lattice copies the lattice structures of lacquer, resin or similar materials already at much lower Burn temperatures or optimized for maximum diffraction efficiency grating profile changed in a disadvantageous for the intended application type.

In a preferred embodiment of the invention, the grid structure is introduced into the surface of a carrier made of quartz glass. For the purposes of the invention, fused silica means silicon dioxide (SiO 2) in an amorphous structure, in contrast to crystalline quartz (quartz).

In alternative embodiments, metal serves as a substrate for the lattice structure. According to the invention, preference is given to an iron-nickel alloy, since this has a particularly favorable coefficient of thermal expansion (CTE). Optionally, the grid structure may also be incorporated in nickel or in a nickel layer.

In a further alternative embodiment, a polyetheretherketone material (PEEK) is provided as a substrate for the lattice structure. Polyetheretherketones not only have very good temperature resistance but also mechanical properties such as high strength and high rigidity, which are advantageous in connection with the conditions of use of the arrangement according to the invention.

The grating is preferably designed as an imaging, concave reflection grating with a blazed surface profile. The preparation is preferably carried out by holographic exposure and subsequent transfer of the profile by means of etching in the quartz glass surface.

The blazed grid profile achieves particularly high efficiencies. The imaging grating advantageously allows a particularly compact design with a large numerical aperture and thus high light conductance, ie high sensitivity and simultaneously low aberrations - respectively a high resolution.

However, an embodiment as a mechanically divided planar grid is also within the scope of the invention.

The basic body of the spectrometer is preferably monolithic, so that CTE differences between different components are avoided and optimum temperature stability of the spectrometer is achieved. A monolithic structure also offers maximum mechanical stability under extreme accelerations, vibrations and shocks. Furthermore, a monolithic structure allows to realize maximum performance in a minimum space.

The arrangement according to the invention is preferably equipped with a detector based on InGaAs sensors. Advantageously, a row or an array of InGaAs sensors with exactly measured distance between the sensor chip and the chip carrier is used and this distance dimension in the dimension of the base body is taken into account so that an optimum resolution of the grating spectrometer is achieved.

Included in the concept of the invention, it is also the case, the connection between the detector and the main body of the spectrometer, namely the connection of the chip carrier with the main body, perform positively. In comparison to adhesive or other indirect connections, as are common in the prior art, it is thus advantageously achieved that at the extreme accelerations, vibrations and shocks, which is subject to the spectrometer in use, no misalignment can occur and so the measurement accuracy also maintained under these conditions.

In a related embodiment, it is provided that the detector is mounted floating relative to the base body, so that itself different length expansions, which may result from CTE differences of the opposing materials, can compensate. In this case, for example, solid-state hinges can be used to hold the detector and arranged so that the chip carrier on the one hand and the base body on the other hand can move in one direction or in two opposite directions against each other. Particularly advantageous are the contact surfaces of the opposing materials with the highest possible planarity run flat.

In likewise advantageous and therefore preferred embodiments of the arrangement according to the invention, it is provided to guide the electromagnetic radiation via folded beam paths. In this context, mirrors are provided for beam deflection, in different embodiments of the invention, metal mirrors without imaging property in order to minimize the space required, or metal mirror with imaging property, so that in addition a further increase in the numerical aperture and thus in turn a higher Conductance, greater sensitivity and lower aberrations, can be achieved according to a higher resolution. Included within the spirit of the invention, however, are embodiments having combinations of imaging and non-imaging mirrors.

The structure of the inventive arrangement allows both the analysis of a fluid that rests in the sample chamber, as well as a fluid flowing through the sample chamber.

The light source and the grating period of the grating spectrometer provided according to the invention are preferably designed for electromagnetic radiation in the near-infrared wavelength range (NIR) or for the typical bands of hydrocarbon.

The output of the detector is connected on site in the bore with an evaluation device, from which the information about the quality of the crude oil is transmitted to the earth's surface. Alternatively it can be provided to transmit the detector output signals wirelessly to an evaluation device, which is located on the earth's surface.

The arrangement according to the invention works according to the known principle of absorption spectroscopy.

The invention further provides the use of at least one embodiment of the above-described spectrometer for integration into a drill pipe for oil wells.

The invention will be explained in more detail with reference to an embodiment. The accompanying drawings show in

1 the positioning of a unitary spectrometer module within a drill pipe for oil wells,

2 the essential functional modules of the spectrometer module 1 ,

Out 1 is in principle the positioning of a spectrometer module 1 having the features of the invention within a drill pipe 2 for introducing an oil well into a rock layer 3 is provided, can be seen. The feed direction V during drilling and the directions of rotation R of the drill string 2 are indicated by arrows.

From the drill pipe 2 For the sake of clarity, only a partial section is shown which should be located as close as possible to the drill head (not shown). The spectrometer module 1 is located - for example, as well as other measuring or test modules 5 . 6 . 7 that are relevant in connection with the drilling or the drilling process, such as temperature or pressure measuring devices - in a recess 4 , which is introduced into the Gestänwandung. The recess 4 is with a cover 8th hermetically sealed. recess 4 and cover 8th extend over a peripheral region of the drill pipe 2 who in 1 indicated by broken lines.

How out 1 further seen, fluid is at standstill of the drill 9 from the rock layer 3 aspirated and for spectral analysis by the spectrometer module 1 directed. The fluid flows through it 9 Channels, for example, in the cover 8th , the spectrometer module 1 and the wall of the drill string 2 are introduced. The spectral analysis is done while the fluid 9 transparent sapphire windows 10 and 11 happens.

The extraction of crude oil from the rock layer 3 For example, by means of a pump, in the cover 8th or integrated into the massive barricade.

2 shows an overview of the main functional groups of the according to 1 into the wall of the drill string 2 integrated spectrometer module 1 , Obviously here are a light source 12 , from the polychromatic radiation 13 starting through the sapphire window 10 . 11 and that between the sapphire windows 10 . 11 flowing fluid 9 through to a spectrometer assembly 14 which comes from the fluid 9 transmitted and scattered radiation 17 analyzed spectroscopically and essentially a focusing optics, a slit diaphragm, the grid used according to the invention, a detector with InGaAs sensors, and optical means for folding the beam path, namely preferably metal mirrors with imaging properties (not shown in detail).

The spectrometer assembly 14 , namely the output of the detector located therein, is via a signal path 15 with a downstream evaluation device 16 connected to the qualitative and / or quantitative evaluation of the analysis results and in turn is connected via a wireless connection with one or more information output devices on the earth's surface (not shown).

LIST OF REFERENCE NUMBERS

1

spectrometer module

2

linkage

3

rock formation

4

recess

5

Measuring or test module

6

Measuring or test module

7

Measuring or test module

8th

cover

9

fluid

10

sapphire window

11

sapphire window

12

light source

13

radiation

14

spectrometer assembly

15

pathway

16

evaluation

17

radiation transmitted and scattered by the fluid

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 602004012554 T2 [0005]
• US 2007/0171414 A1 [0006]

Claims (14)

Arrangement for determining spectral properties of a borehole fluid under the influence of high temperature and mechanical stresses at the location of occurrence of the fluid, comprising - a source of polychromatic electromagnetic radiation ( 13 ), - optical means for aligning the electromagnetic radiation ( 13 ) on the fluid ( 9 ), and - a spectral analysis device in the form of a grating spectrometer, designed to detect the spectrum of the fluid ( 9 ) transmitted or scattered electromagnetic radiation ( 17 ), characterized in that - the grating spectrometer has an original grating with a grating period tuned to radiation wavelengths λ in the range from 200 nm to 4000 nm. Arrangement according to claim 1, wherein the grid is designed as a reflection grating. Arrangement according to claim 1 or 2, wherein the grid is introduced into the surface of a substrate made of quartz glass and is preferably provided with a reflective coating. Arrangement according to claim 1 or 2, wherein the grid is introduced into the surface of a substrate made of an iron-nickel alloy and is preferably provided with a reflective coating. Arrangement according to claim 1 or 2, wherein the grid structure is introduced into nickel or into a nickel layer and is preferably provided with a reflective coating. Arrangement according to claim 1 or 2, wherein the grid structure is introduced into a polyetheretherketone material (PEEK) and is preferably provided with a reflective coating. Arrangement according to one of the preceding claims, wherein the grid is designed as a mechanically split planar lattice, but preferably as imaging, concave reflection grille with blazed surface profile. Arrangement according to one of the preceding claims, wherein the grating spectrometer is equipped with a detector based on one or more InGaAs sensors, in particular with a row or an array of InGaAs sensors with exactly measured distance between the sensor chip and the chip carrier and a dimensionally adapted to this distance Spektrometergrundkörper. Arrangement according to claim 8, wherein the connection between the chip carrier and the main body of the spectrometer is designed to be positive, wherein preferably the chip carrier is mounted floating relative to the base body. Arrangement according to one of the preceding claims, wherein the electromagnetic radiation is conducted via folded beam paths, wherein for beam deflection mirror, preferably metal mirror without imaging property, particularly preferably metal mirror are provided with imaging property. Arrangement according to one of the preceding claims, wherein the light source and the grating period of the grating spectrometer for electromagnetic radiation in the wavelength range of the near infrared (NIR) or for the typical bands of hydrocarbon are designed. Arrangement according to one of the preceding claims, in which the passage of the fluid ( 9 ) is provided through the beam path between transparent windows, which are preferably made of sapphire. Arrangement according to one of the preceding claims, wherein the output of the detector with an evaluation device ( 16 ) from which the information about the quality of the fluid ( 9 ) is transmitted to the earth's surface. Use of a spectrometer with the features according to claims 1 to 11 within a drill string ( 2 ) for oil wells near the drill head for the purpose of determining the spectral properties of well fluids during drilling.

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