JP3048415B2 - Crust fracture detection system - Google Patents
Crust fracture detection systemInfo
- Publication number
- JP3048415B2 JP3048415B2 JP15262991A JP15262991A JP3048415B2 JP 3048415 B2 JP3048415 B2 JP 3048415B2 JP 15262991 A JP15262991 A JP 15262991A JP 15262991 A JP15262991 A JP 15262991A JP 3048415 B2 JP3048415 B2 JP 3048415B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- fracture
- well
- magnetic
- vertical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
Landscapes
- Geophysics And Detection Of Objects (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、磁性流体トレーサを
利用した地殻内フラクチャ（き裂）構造検知システムに
関し、特に、計測システムの中核を構成する３軸磁力計
のうち、改良された磁場ソースを用いた地殻内フラクチ
ャ構造検知システムの改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for detecting a fracture (crack) structure in the crust using a magnetic fluid tracer, and more particularly to an improved magnetic field source among three-axis magnetometers constituting a core of a measurement system. The present invention relates to an improvement of a fracturing structure detection system in the crust using GIS.
【０００２】[0002]
【従来の技術】磁性流体トレーサによる地下フラクチャ
（き裂）確認法技術は、ＥＭ法（電磁誘導法）の応用技
術であり、坑井に貫入した「フラクチャの中の現実に流
動する部分」に磁性流体トレーサ（以下、「ＭＦＴ」と
省略する。）を流し込むことにより、地下の物性値（こ
の場合、透磁率）に人工的な変化を起こして、それによ
る電磁場の変化をとらえ、これによって、フラクチャの
傾斜（デイップ）や走行（ストライキ）あるいはＭＦＴ
の進展する方向を把握することが可能となる。2. Description of the Related Art Underground fracture (crack) confirmation technology using a magnetic fluid tracer is an application technology of the EM method (electromagnetic induction method), and is applied to the "part of a fracture that actually flows" penetrating a well. By pouring in a magnetic fluid tracer (hereinafter abbreviated as “MFT”), an artificial change is caused in the underground physical property value (in this case, magnetic permeability), and the change in the electromagnetic field caused by the change is captured. Fracture incline (dip), run (strike) or MFT
It is possible to grasp the direction in which
【０００３】本願出願人は、この方法による地下フラク
チャ確認技術について、既に提案している（特許願平成
１年第３４０１８７号 発明の名称「人工磁場を利用し
た地殻内亀裂形状、賦存状態三次元検知システム」）。The applicant of the present application has already proposed a technique for confirming underground fractures by this method (Patent Application No. 2001-340187, entitled "Crack Shape in Crust Using Artificial Magnetic Field, Existence State 3D") Detection system ").
【０００４】この検知システムでは、予備水圧破砕の中
で、ＭＦＴの流れ込んだ（実際の地熱流体の流動する）
フラクチャの坑井周辺でのデイップとストライキを得る
ことに関して、有効な手段であった。特に、地熱地帯の
ように地質的に複雑な地層中では導電率（対応する探査
技術＝比抵抗法）・誘電率（レーダ法）・弾性波速度
（地震法）の変化が大きく、特定のフラクチャと地層で
の物性値の差を明確に区分できない場合を、ＭＦＴの注
入されたフラクチャの透磁率変化を電磁法で補足するこ
ととするため、地熱地帯の複雑な地層中でもフラクチャ
からの影響のみを抽出できるという利点を有していた。[0004] In this detection system, during the preliminary hydraulic crushing, the MFT flows into (the actual geothermal fluid flows).
It was an effective means of obtaining dips and strikes around the fractured well. In particular, in geologically complex geological layers such as geothermal areas, the conductivity (corresponding exploration technology = resistivity method), the permittivity (radar method), and the elastic wave velocity (seismic method) change greatly, and specific fractures occur. In the case where the difference between the physical property value and that of the stratum cannot be clearly distinguished, the change in the magnetic permeability of the fracture injected with MFT will be supplemented by the electromagnetic method. It had the advantage that it could be extracted.
【０００５】上記出願人の提案に係る計測システムにつ
いて説明すると以下のとおりである。The measuring system according to the proposal of the applicant will be described below.
【０００６】図５は、従来の計測システムの概念図であ
る。図１において、２１は調査井、２２は垂直発振コイ
ル、２３は、３軸磁力計、２４は、内部に前記垂直発振
コイル２２および３軸磁力計２３が組み込まれ、前記調
査坑井２１内に釣り降ろされた検層プローブ、２５は、
データ処理コンピュータを搭載した検層用スキッドまた
は検層車である。また、図中、２６は、前記垂直発振コ
イルによって生じた人工交流磁場を示し、２７は、高透
磁率トレーサ（ＭＦＴ）が注入された地下のフラクチャ
を概念的に示したものである。FIG. 5 is a conceptual diagram of a conventional measurement system. In FIG. 1, 21 is a survey well, 22 is a vertical oscillation coil, 23 is a three-axis magnetometer, and 24 is the vertical oscillation coil 22 and a three-axis magnetometer 23 incorporated therein. The crawled logging probe, 25,
A logging skid or logging vehicle equipped with a data processing computer. In the figure, reference numeral 26 denotes an artificial AC magnetic field generated by the vertical oscillation coil, and reference numeral 27 conceptually shows an underground fracture into which a high permeability tracer (MFT) is injected.
【０００７】ところが、本願出願人が提案したこのシス
テムでは、計測システムの中核を構成する垂直発振コイ
ル２２および３軸磁力計２３に関し、特に、地熱井での
使用を想定して、それらを組み込む検層プローブ２４に
関し、外径３．５インチ、長さ３ｍ強の耐圧容器に収容
する形状、構造としたため、磁場ソースである垂直発振
コイル２２と３磁磁力計間の間隔距離に構造上の制限が
あった。However, in this system proposed by the present applicant, the vertical oscillation coil 22 and the three-axis magnetometer 23, which constitute the core of the measurement system, are particularly designed for use in geothermal wells. The layer probe 24 is housed in a pressure-resistant container having an outer diameter of 3.5 inches and a length of slightly more than 3 m. The structure and the structure of the layer probe 24 limit the distance between the vertical oscillation coil 22 as a magnetic field source and the 3 magnetometer. was there.
【０００８】同一坑井内でこれを前記垂直発振コイル２
２および３軸磁力計２３を組み込んだ検層プローブ２４
は、これらを同一容器内に収納するので、前記垂直発振
コイル２２と３軸磁力計を容器内の上端と下端に組み込
んだとしても、その間隔は約３ｍと短く、坑井近傍の細
かな磁場変化を捉えることは比較的容易であるとして
も、前記ＭＦＴが、坑井を中心に数１０ｍ以上先まで延
びていくような場合には、この坑井内に収容された垂直
発振コイルで、それを補足することは難しいという欠点
があった。In the same well, the vertical oscillation coil 2
Logging probe 24 incorporating two and three axis magnetometer 23
Since these are housed in the same container, even if the vertical oscillation coil 22 and the three-axis magnetometer are incorporated in the upper and lower ends of the container, the distance between them is as short as about 3 m, and the fine magnetic field near the well is small. Even if it is relatively easy to catch the change, if the MFT extends tens of meters or more around the well, the vertical oscillation coil housed in the well may There was a drawback that it was difficult to supplement.
【０００９】[0009]
【課題を解決するための手段】上記問題点を解決するた
めに、本願発明では、前記垂直発振コイル２２を坑井内
に挿入する検層プローブ２４の容器内に配置しないで、
そのかわりに、挿入する調査坑井２１を含むあるいはそ
れを含まない地表面に磁場ソースを設置して、それに可
聴周波数帯域の交流を流すことで、垂直交流磁場（１０
Ｈｚ−数ｋＨｚ程度）を発生させ、調査坑井２１内の検
層プローブ２４内の３軸磁力計２３で受信し、坑内３軸
磁場プロファイル計測できるようにしたものである。In order to solve the above problems, according to the present invention, the vertical oscillation coil 22 is not disposed in the vessel of the logging probe 24 inserted into the well,
Instead, a magnetic field source is installed on the surface of the earth including or not including the investigation well 21 to be inserted, and an alternating current in the audible frequency band is supplied to the magnetic field source, so that the vertical alternating magnetic field (10
(Several Hz-about several kHz), and is received by the three-axis magnetometer 23 in the logging probe 24 in the investigation well 21 so that the three-axis magnetic field profile measurement in the downhole can be performed.
【００１０】[0010]
【作用】本願発明は、ＭＦＴを流入した坑井を含むまた
は含まない地表面に磁場ソースを設置して、それに可聴
周波数帯域の交流を流して垂直交流磁場（数Ｈｚ−数ｋ
Ｈｚ程度）を発生させ、これを坑井内の検層プローブの
３軸磁力計で受信し、調査坑井を中心に数１００ｍ以上
離れた距離においても、その地下に存存するフラクチャ
構造（ディップ、ストライキ）を検知するというもので
ある。According to the present invention, a magnetic field source is installed on the ground surface including or not including a well into which an MFT has flowed, and an alternating current in an audible frequency band is supplied to the magnetic field source to apply a vertical alternating magnetic field (several Hz to several k).
Hz), and this is received by the three-axis magnetometer of the logging probe in the well, and the fracture structure (dip, strike) existing underground even at a distance of several hundred meters or more around the investigation well ) Is detected.
【００１１】[0011]
【実施例】本願発明を実施例図面に従って説明する。図
１は、本願発明の一実施例計測システムを示した概念図
であり、１は、フラクチャ７に遭遇した調査坑であっ
て、この調査坑１から磁性流体トレーサ（ＭＦＴ）を注
入し、また、３軸磁力計からなる坑井内レシーバ３を組
み込んだ検層プローブ４を釣り降ろす調査坑である。ま
た、２は、前記調査坑１を含む地表面に配置した４００
メートル四方のループ式コイルからなる地表磁場ソース
であり、この実施例では、この地表磁場ソース２に可聴
周波数帯域の交流電流が印加される。６は、この交流電
流で発生する垂直交流磁場であり、７は、磁性流体トレ
ーサ（ＭＦＴ）が注入された地下のフラクチャを概念的
に示すものである。BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a conceptual diagram showing a measurement system according to an embodiment of the present invention. Reference numeral 1 denotes a survey pit that has encountered a fracture 7, and a magnetic fluid tracer (MFT) is injected from the survey pit 1; This is a survey pit for fishing down a logging probe 4 incorporating a downhole receiver 3 composed of a three-axis magnetometer. Reference numeral 2 denotes 400 arranged on the ground surface including the investigation pit 1.
This is a surface magnetic field source composed of a loop-type coil of a meter square. In this embodiment, an AC current in an audio frequency band is applied to the surface magnetic field source 2. Numeral 6 denotes a vertical alternating magnetic field generated by the alternating current, and numeral 7 conceptually shows an underground fracture into which a magnetic fluid tracer (MFT) has been injected.
【００１２】このようなシステム概略の下で、まず、最
初に、フラクチャー７に掘り下げられた調査坑井１か
ら、高透磁性を有する粒状磁性体のトレーサを注入し、
その後、３軸磁力計からなる坑井内レシーバ３を組み込
んだ検層プローブ４を釣り降ろす。そして、前記調査坑
１を含む地表面または該調査坑１を含まない地表面に、
４００メートル四方のループ式コイルからなる地表磁場
ソース２を配置し、この地表磁場ソース２に可聴周波数
帯域の交流電流を印加した。Under such a system outline, first, a tracer of a granular magnetic material having high magnetic permeability is injected from the investigation well 1 drilled into the fracture 7.
Thereafter, the logging probe 4 incorporating the downhole receiver 3 composed of a three-axis magnetometer is taken off. And, on the ground surface including the search pit 1 or the ground surface not including the search pit 1,
An earth magnetic field source 2 composed of a loop coil of 400 m square was arranged, and an alternating current in an audible frequency band was applied to the earth magnetic field source 2.
【００１３】なお、この実施例に使用する３軸磁力計に
関し、モデル計算シミュレーションによる評価を行った
結果、２０００ｍ級坑井を用いた場合には、検出に必要
な磁力計感度が １ ｘ １０-3［ｎＴ］のものが必要
であることが判明したので、これを用いた。As a result of evaluating the three-axis magnetometer used in this embodiment by model calculation simulation, when a 2000 m class well is used, the magnetometer sensitivity required for detection is 1 × 10 −. 3 [nT] was found to be necessary and was used.
【００１４】また、磁性流体トレーサ（ＭＦＴ）として
は、本願出願人が、既に提案した上記発明においては、
粒状の高い透磁性（初透磁率１００程度）を有し、流動
しやすい粒径のもの、例えば、粒径＝１〜数１０ミクロ
ンのものを使用した。また、熱水に使用する為、キュリ
ー点の高い高温安定性のものを使用した。また、地下熱
水層の中で高流動性を有するものであることが必要であ
り、水に対する分散性に富み、比重が低いものが好まし
い。[0014] As the magnetic fluid tracer (MFT), in the above-mentioned invention already proposed by the present applicant,
Particles having a high granular magnetic permeability (about 100 in initial magnetic permeability) and having a particle size that easily flows, for example, particles having a particle size of 1 to several tens of microns were used. In addition, for use in hot water, a material having a high Curie point and high temperature stability was used. It is necessary that the underground hot water layer has high fluidity, and it is preferable that the underground hot water layer has high dispersibility in water and low specific gravity.
【００１５】さらに、大規模なフラクチャに対応するた
め、大量に使用しなければならず、その製造コストがで
きるだけ低いものを使用する必要があり、従来、使用さ
れていたセンダスト粉（通常に粉砕した場合には、初期
比透磁率＝４５）より、安価で大量使用にコスト的に耐
え得る、鉄粉、フェライト粉の使用を試みた。Furthermore, in order to cope with large-scale fractures, it must be used in large quantities, and it is necessary to use a material whose production cost is as low as possible. In this case, an attempt was made to use an iron powder or a ferrite powder, which was cheaper than the initial relative magnetic permeability = 45) and could withstand mass use in terms of cost.
【００１６】コストの点を考えると、鉄粉（初期比透磁
率＝２４）が、フェライト粉（初期透磁率＝１５程度）
より好ましい。Considering the cost, iron powder (initial relative permeability = 24) is replaced by ferrite powder (initial permeability = about 15).
More preferred.
【００１７】特に、この実施例発明では、注入量を多く
しなければならないことから、初期比透磁率はセンダス
トの５０〜３０％程度でも、大量に注入できる廉価な材
料である鉄粉を使用した場合でも、前記３軸磁力計を若
干変更することにより充分検出可能なことを見い出し
た。すなわち、上記使用する３軸磁力計について、その
仕様を従来より低周波数（１０［Ｈｚ］）寄りに変更す
ることにより、常温（１００℃以下）の使用条件下（１
０［Ｈｚ］〜数［ＫＨｚ］）でセンサのノイズレベル１
×１０-3［ｎＴ］を可能とした。In particular, in the present invention, since the injection amount must be increased, iron powder which is an inexpensive material that can be injected in large quantities is used even if the initial relative permeability is about 50 to 30% of sendust. In this case, it has been found that the detection can be sufficiently performed by slightly changing the three-axis magnetometer. That is, by changing the specifications of the three-axis magnetometer used above to a lower frequency (10 [Hz]) than the conventional one, the operating conditions (1
0 [Hz] to several [KHz]) noise level of sensor 1
× 10 -3 [nT] was made possible.
【００１８】この実施例では、上記のような中程度の透
磁率を有する磁性粉体（鉄粉等）を使用することによ
り、実施コストの逓減を図り、本願発明に係る計測シス
テムの実用性の向上を図ることができたものであるが、
フラクチャ規模が極めて小さく僅かな分量の注入しか必
要ないような特殊の場合には検出能力の向上を図るため
に、従来同様、高透磁率で効率の良くなるセンダストを
使用しても良い。In this embodiment, the use of the magnetic powder having a medium permeability as described above (iron powder or the like) reduces the implementation cost and makes the measurement system according to the present invention practically useful. Although it was possible to improve,
In special cases where the fracture scale is extremely small and only a small amount of injection is required, sendust having high magnetic permeability and high efficiency may be used as in the prior art in order to improve the detection capability.
【００１９】このような条件の下、実際の地熱地帯での
使用を想定して、目標可探進度２０００ｍ（地層内の平
均な被抵抗＝５０Ω・ｍ）における数値モデル計算によ
る検出能力評価を行った。Under these conditions, assuming use in an actual geothermal area, the detection capability is evaluated by a numerical model calculation at a target detectability of 2000 m (average resistance in the formation = 50 Ω · m). Was.
【００２０】図２は、このような数値モデル計算を行う
ための計算モデルを示す概念図である。すなわち、母岩
１０の比抵抗＝５０Ω・ｍとし、地下にＭＦＴで充満さ
れた正方形状のＬｍ×Ｌｍ×０．００１ｍ、ｘ軸方向を
中心に３０°回転した一定の傾きのフラクチャシート１
１が存在し、坑井１は、深度２０００ｍの地点で、この
フラクチャシート１１を貫いていると仮定した。そし
て、上記フラクチャシート１１に充満させる磁性流体
（ＭＦＴ）は、比重８、比透磁率２４の材料が４倍の容
積の水（比重１）に均等に分散している仮定した。この
ような条件の下、地表に、例えば、４００ｍ×４００ｍ
の正方形ループ（１０ターン）２に電流２０［Ａ］を通
電して３２Ｍ［Ａ・ｍ2］の出力を仮定して、地表磁場
ソース２の適正周波数およびシート１１の伸び（大き
さ）の検知を行った。なお、シート１１の傾きを３０°
一定と仮定したが、これは、垂直から水平にシート１１
が傾く途中で水平磁場、垂直磁場の両方の傾向が判るよ
うに、中間的な場所として便宜上このように仮定した。FIG. 2 is a conceptual diagram showing a calculation model for performing such a numerical model calculation. That is, the resistivity of the host rock 10 is set to 50 Ω · m, and the fracture sheet 1 is a square Lm × Lm × 0.001 m filled with MFT underground and has a constant inclination rotated 30 ° about the x-axis direction.
1 is present, and it is assumed that the well 1 penetrates the fracture sheet 11 at a depth of 2000 m. The magnetic fluid (MFT) filled in the fracture sheet 11 is assumed to have a material having a specific gravity of 8 and a relative magnetic permeability of 24, which is evenly dispersed in four times the volume of water (specific gravity of 1). Under such conditions, for example, 400 m × 400 m
Assuming an output of 32 M [A · m 2 ] by applying a current of 20 [A] to a square loop (10 turns) 2 of the above, detection of an appropriate frequency of the surface magnetic field source 2 and elongation (size) of the sheet 11 Was done. Note that the inclination of the sheet 11 is 30 °.
It was assumed that this was constant,
For the sake of convenience, this is assumed as an intermediate location so that the tendency of both the horizontal magnetic field and the vertical magnetic field can be understood during the tilting.
【００２１】その結果、地表磁場ソース２の適正周波数
について、１、３、１０、３０、１００Ｈｚの各周波数
について計測を行った結果、図３に示される結果を得
た。図３において、左上図は、水平磁場（実部）を、中
央上図は、垂直磁場（実部）を、右上図は、垂直磁場
（実部）を示し、左下図は、水平磁場（虚部）を、中央
下図は、垂直磁場（虚部）を、右下図は、垂直磁場（虚
部）を示している。横軸は、磁場の大きさ［ｎＴ］を示
し、縦軸は、深度［ｍ］（フラクチャシート１１の中心
深度＝０ｍ、地表磁場ソース２の位置（地表）＝２００
０ｍ）を示す。なお、Ｈｙは、ストライキ方向であり、
磁場応答は０になっている。As a result, the proper frequency of the surface magnetic field source 2 was measured for each frequency of 1, 3, 10, 30, and 100 Hz, and the result shown in FIG. 3 was obtained. 3, the upper left diagram shows the horizontal magnetic field (real part), the upper middle diagram shows the vertical magnetic field (real part), the upper right diagram shows the vertical magnetic field (real part), and the lower left diagram shows the horizontal magnetic field (imaginary part). Part), the lower center figure shows a vertical magnetic field (imaginary part), and the lower right figure shows a vertical magnetic field (imaginary part). The horizontal axis represents the magnitude [nT] of the magnetic field, and the vertical axis represents the depth [m] (the center depth of the fracture sheet 11 = 0 m, the position of the ground magnetic field source 2 (ground surface) = 200
0m). Hy is the strike direction,
The magnetic field response is zero.
【００２２】この結果から、深度２０００ｍでは、３０
Ｈｚ前後から信号の減衰が大きくなりはじめて、１００
Ｈｚ以上では、２次磁場が小さすぎて、深部での使用が
難しいことが判る。したがって、深度２０００ｍにおけ
る適正周波数は数Ｈｚから１０Ｈｚ程度が好ましいもの
であることが知り得た。From these results, at a depth of 2000 m, 30
When the signal attenuation starts to increase from around
When the frequency is higher than Hz, the secondary magnetic field is too small, so that it is difficult to use in a deep part. Therefore, it has been found that the appropriate frequency at a depth of 2000 m is preferably about several Hz to 10 Hz.
【００２３】また、シート１１の伸び（大きさ）の検知
に関しては、フラクチャ・アパチャ＝１ｍｍ（一定）の
とき、周波数＝１０Ｈｚでの２次磁場の応答を図４に示
す。図４においても、左上図は、水平磁場（実部）を、
中央上図は、垂直磁場（実部）を、右上図は、垂直磁場
（実部）を示し、左下図は、水平磁場（虚部）を、中央
下図は、垂直磁場（虚部）を、右下図は、垂直磁場（虚
部）を示している。同様に、横軸は、磁場の大きさ［ｎ
Ｔ］を示し、縦軸は、深度［ｍ］（フラクチャシート１
１の中心深度＝０ｍ、地表磁場ソース２の位置（地表）
＝２０００ｍ）を示す。なお、Ｈｙについても、同様
に、ストライキ方向を示し、同様に、磁場応答は０にな
っている。FIG. 4 shows the response of the secondary magnetic field at a frequency of 10 Hz when the fracture / aperture is 1 mm (constant) with respect to the detection of the elongation (size) of the sheet 11. Also in FIG. 4, the upper left figure shows the horizontal magnetic field (real part),
The upper center figure shows the vertical magnetic field (real part), the upper right figure shows the vertical magnetic field (real part), the lower left figure shows the horizontal magnetic field (imaginary part), the lower center figure shows the vertical magnetic field (imaginary part), The lower right figure shows the vertical magnetic field (imaginary part). Similarly, the horizontal axis represents the magnitude of the magnetic field [n
T], and the vertical axis indicates the depth [m] (fracture sheet 1
Center depth of 1 = 0 m, position of surface magnetic field source 2 (ground surface)
= 2000m). Note that Hy also indicates the strike direction, and similarly, the magnetic field response is zero.
【００２４】この結果から、シート１１の大きさに応じ
て、得られる２次磁場の強度が顕著に変化していること
が知り得、また、注入量の増加に応じて大きな強度が得
られていることから、大きな広がりを有するフラクチャ
７を捕捉するのに有効であることが知り得る。From this result, it can be seen that the intensity of the obtained secondary magnetic field changes remarkably according to the size of the sheet 11, and that the intensity increases as the injection amount increases. Therefore, it can be understood that the method is effective for capturing a fracture 7 having a large spread.
【００２５】[0025]
【発明の効果】この発明は、地熱地帯の高温下での測定
の制約の下や、地熱地帯特有の複雑な地質構造のため、
フラクチャの生成の有無に関わらず地下の物理的構造
（導電率、誘電率、弾性波速度等）が複雑となり、その
ため、フラクチャによる物性値の変化がバックグラウン
ドとなる地質構造のもつ複雑な物性値変化の中に埋没す
ることなく、坑井に貫入した「フラクチャの中の現実に
流体の流動する部分」に磁性流体トレーサ（ＭＦＴ）を
流し込むことによって、地下の物性値（本発明の場合、
透磁率）に人工的変化をお越させてそれによって生じる
電磁場の変化を捉えることによって、フラクチャの傾斜
（ディップ）や走向（ストライキ）あるいはＭＦＴの進
展していった方向を把握することが容易に可能となっ
た。したがって、予備水圧破砕の中で、ＭＦＴの流れ込
んだ（実際の地熱流体の流動する）フラクチャの坑井周
辺でのディップとストライキを得るに極めて有効な手段
を確立することができる。According to the present invention, there are restrictions on measurement at high temperatures in a geothermal area, and complicated geological structures unique to a geothermal area.
Underground physical structure (conductivity, dielectric constant, elastic wave velocity, etc.) becomes complicated regardless of the presence or absence of fracture, and therefore, the complex physical property value of the geological structure where the change in physical property value due to fracture becomes the background By flowing a magnetic fluid tracer (MFT) into the “part of the fracture where the fluid actually flows” without buried in the change, the physical properties of the underground (in the case of the present invention,
It is easy to grasp the inclination (dip) and strike (strike) of the fracture or the direction in which the MFT has developed by capturing the change in the electromagnetic field caused by the artificial change in the magnetic permeability. It has become possible. Therefore, it is possible to establish a very effective means for obtaining a dip and a strike around the well of the fracture into which the MFT flows (the actual geothermal fluid flows) during the preliminary hydraulic fracturing.
【００２６】特に、地熱地帯のように地質的に複雑な地
層中では導電率（対応する探査技術）、誘電率（レーダ
法）、弾性波速度（地震法）の変化が大きく、特定のフ
ラクチャと地層での物性値の差を明確に区分できない場
合であっても、地下での局所的な透磁率の変化は比較的
小さいため、坑井に貫入したフラクチャに磁性流体トレ
ーサ（ＭＦＴ）を流し込むことによって、注入されたフ
ラクチャの透磁率変化を電磁法で補足することにより、
地熱地帯の複雑な地層中でもフラクチャからの影響のみ
を抽出しやすい利点を有している。In particular, in a geologically complex geological layer such as a geothermal zone, the conductivity (corresponding exploration technique), the dielectric constant (radar method), and the elastic wave velocity (seismic method) change greatly, and a specific fracture Even if the difference in physical properties in the stratum cannot be clearly distinguished, the magnetic fluid tracer (MFT) must be poured into the fracture penetrating into the well because the local permeability change underground is relatively small. By supplementing the permeability change of the injected fracture with the electromagnetic method,
It has the advantage that it is easy to extract only the effects from fractures, even in complex geological formations.
【００２７】また、ターゲットと計測器の間に大規模な
破砕帯が存在した場合には、各種信号（電磁波、弾性
波）のエネルギー減衰が大きく遠方の情報を得にくいの
が通常であるが、比較的に低周波数帯域である可聴周波
数帯の電磁波を信号源とするため、信号の減衰も小さ
く、遠方（深部）の目的物に対しても有効な補足が可能
となる。When a large crush zone exists between the target and the measuring instrument, the energy of various signals (electromagnetic waves, elastic waves) is greatly attenuated, and it is usually difficult to obtain distant information. Since an electromagnetic wave in an audible frequency band, which is a relatively low frequency band, is used as a signal source, signal attenuation is small, and effective supplementation can be performed even for a distant (deep) target.
【図１】図１は、本願発明の一実施例計測システムを示
した概念図である。FIG. 1 is a conceptual diagram showing a measurement system according to an embodiment of the present invention.
【図２】図２は、このような数値モデル計算を行うため
の計算モデルを示す概念図である。FIG. 2 is a conceptual diagram showing a calculation model for performing such a numerical model calculation.
【図３】図３は、本願発明の計算モデルによって得られ
た水平磁場（実部）、垂直磁場（実部）、水平磁場（虚
部）、垂直磁場（虚部）を示すグラフである。FIG. 3 is a graph showing a horizontal magnetic field (real part), a vertical magnetic field (real part), a horizontal magnetic field (imaginary part), and a vertical magnetic field (imaginary part) obtained by the calculation model of the present invention.
【図４】図４は、本願発明の計算モデルによって得られ
た水平磁場（実部）、垂直磁場（実部）、水平磁場（虚
部）、垂直磁場（虚部）を示すグラフである。FIG. 4 is a graph showing a horizontal magnetic field (real part), a vertical magnetic field (real part), a horizontal magnetic field (imaginary part), and a vertical magnetic field (imaginary part) obtained by the calculation model of the present invention.
【図５】図５は、従来の計測システムの概念図である。FIG. 5 is a conceptual diagram of a conventional measurement system.
１ 調査坑井 ２ 地表磁場ソース ３ 坑井内レシーバ ４ 検層プローブ ７ フラクチャ ８ 比重 １０ 母岩 Reference Signs List 1 investigation well 2 surface magnetic field source 3 downhole receiver 4 logging probe 7 fracture 8 specific gravity 10 host rock
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｅ２１Ｂ 47/16 47/18 (56)参考文献 特開 平３−202587（ＪＰ，Ａ) 米国特許4323848（ＵＳ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01V 3/26 E21B 47/00 E21B 47/01 E21B 47/12 E21B 47/14 E21B 47/16 E21B 47/18 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FIE21B 47/16 47/18 (56) References JP-A-3-202587 (JP, A) US Patent 4,323,848 (US, A) ( 58) Field surveyed (Int.Cl. 7 , DB name) G01V 3/26 E21B 47/00 E21B 47/01 E21B 47/12 E21B 47/14 E21B 47/16 E21B 47/18
Claims (1)
性を有する磁性流体トレーサと、 前記磁性体トレーサを注入する調査坑井を含むあるいは
それを含まない地表面に設置され、垂直交流磁場（１０
Ｈｚ−数ｋＨｚ程度）を発生させる単一または複数の磁
場ソースと、 前記調査坑井内に釣り降ろされ、坑内３軸磁場プロファ
イル計測をする３軸磁力計からなる検層プローブとから
なり、 その調査坑井周辺の地下のフラクチャ構造（ディップ、
ストライキ）を検知する地殻内フラクチャ構造検知シス
テム。1. A magnetic fluid tracer, which is injected into a fracture in the crust and has high magnetic permeability, and is installed on the ground surface including or not including an investigation well into which the magnetic tracer is injected, and a vertical alternating magnetic field ( 10
(Several Hz-about several kHz), and a logging probe consisting of a three-axis magnetometer for measuring a three-axis magnetic field profile down the downhole in the survey well, and measuring the three-axis magnetic field profile. Underground fracture structure around the well (dip,
Crust fracture structure detection system that detects strikes).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15262991A JP3048415B2 (en) | 1991-05-28 | 1991-05-28 | Crust fracture detection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15262991A JP3048415B2 (en) | 1991-05-28 | 1991-05-28 | Crust fracture detection system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0666950A JPH0666950A (en) | 1994-03-11 |
| JP3048415B2 true JP3048415B2 (en) | 2000-06-05 |
Family
ID=15544566
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15262991A Expired - Fee Related JP3048415B2 (en) | 1991-05-28 | 1991-05-28 | Crust fracture detection system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3048415B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030205376A1 (en) | 2002-04-19 | 2003-11-06 | Schlumberger Technology Corporation | Means and Method for Assessing the Geometry of a Subterranean Fracture During or After a Hydraulic Fracturing Treatment |
| GB2492711B (en) | 2010-04-27 | 2016-03-23 | Halliburton Energy Services Inc | Fracture characterization by interferometric drillbit imaging, time reversal imaging of fractures using drill bit seismics, and monitoring of fracture |
| US8991260B2 (en) | 2010-08-05 | 2015-03-31 | Akebono Brake Industry Co., Ltd. | Pseudo rock and analysis system using the same |
| CN104166168B (en) * | 2013-05-17 | 2016-10-12 | 中国石油天然气集团公司 | A kind of well excites electromagnetic data acquisition method with integrated ground |
| CN103244103B (en) * | 2013-05-20 | 2014-08-20 | 中国石油大学(华东) | Nano-magnetic-fluid-based hydraulic fracturing fracture real-time monitoring system and nano-magnetic-fluid-based hydraulic fracturing fracture real-timemonitoring method |
| CN104459821A (en) * | 2014-11-18 | 2015-03-25 | 中国神华能源股份有限公司 | Physiotherapeutic thermal mineral water exploration method |
| WO2017010617A1 (en) * | 2015-07-14 | 2017-01-19 | 한국지질자원연구원 | Method for detecting change in underground environment by using magnetic induction, detection sensor and detection system |
-
1991
- 1991-05-28 JP JP15262991A patent/JP3048415B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0666950A (en) | 1994-03-11 |
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