【摘要】：在石油鉆井領(lǐng)域尤其是海上鉆井中,隨鉆電磁波測量技術(shù)因其在地質(zhì)導(dǎo)向和邊界探測中具有重要價(jià)值而得到廣泛開發(fā)和應(yīng)用。然而傳統(tǒng)的隨鉆測量技術(shù)均采用同軸發(fā)射和接收天線,雖然可以確定油氣儲層的位置,但由于缺乏方位靈敏性,無法提供各向異性儲層的定向信息,因而不足以對各向異性地層進(jìn)行評價(jià)。自2000年開始,隨著定向隨鉆測量的引入,產(chǎn)生了新一代定向測井儀器。這些儀器除含有軸向天線外,還有傾斜和橫向天線,能夠精確測量地層各向異性、傾斜角和方位角,提高了地層界面預(yù)測和地質(zhì)導(dǎo)向的能力。本文通過研究電磁波在各層介質(zhì)中的反射和透射規(guī)律,導(dǎo)出介質(zhì)層中電磁波的解析表達(dá)式,計(jì)算電磁波電阻率隨鉆測量的幅度衰減和相移,分析定向電磁測量對地層界面的靈敏性。同時計(jì)算隨鉆電阻率儀器激發(fā)的電磁場隨儀器方位變化的關(guān)系,分析方位電阻率成像的規(guī)律。首先,本文從麥克斯韋方程出發(fā),將測井儀器發(fā)射源簡化為一個磁偶極子,其在層狀地層中產(chǎn)生的電磁場可以分解為電場矢量垂直于入射面的線性極化波(TE波)和平行于入射面的線性極化波(TM波),通過研究這兩種波在各層介質(zhì)中的反射和透射規(guī)律,利用邊界條件得出磁偶極子在水平層狀介質(zhì)中的解析表達(dá)式,并以此為基礎(chǔ)計(jì)算電磁波隨鉆測量的幅度衰減和相移。其次,采用不同目的層厚度的三層和多層地層模型,計(jì)算定向幅度衰減隨儀器方位變化的關(guān)系,分析方位電阻率成像的分辨率。結(jié)果表明,當(dāng)目的層厚度較大時,通過成像可以確定地層邊界；但當(dāng)厚度逐漸減小,成像效果變差,甚至可能曲解真實(shí)地層情況,影響測井決策。最后,根據(jù)電磁波隨鉆測量的幅度衰減和相移表達(dá)式,結(jié)合方位電阻成像,分析定向電磁測量對地層界面的靈敏性,研究地層相對傾角和接收天線傾角對電磁測量的影響。計(jì)算結(jié)果表明,線圈距和目的層厚度越大、頻率越低、目的層和圍巖電阻率差別越大,定向電磁測量的探測范圍越大;隨著地層傾角和接收天線傾角的增加,定向電磁響應(yīng)在接近地層界面時的變化越明顯,對地層界面的靈敏性越強(qiáng)。同時分析定向電磁測量信號的方位分辨特性,實(shí)現(xiàn)對地層界面的準(zhǔn)確預(yù)測。以上工作和結(jié)論對方位電阻率測井具有實(shí)際意義,為分析定向電磁響應(yīng)和方位電阻成像提供了理論基礎(chǔ)。
[Abstract]:In the field of petroleum drilling, especially in offshore drilling, electromagnetic wave measurement while drilling has been widely developed and applied because of its important value in geological guidance and boundary detection. However, the traditional techniques of while drilling adopt coaxial transmitting and receiving antenna. Although the location of oil and gas reservoir can be determined, the orientation information of anisotropic reservoir can not be provided because of the lack of azimuth sensitivity. Therefore, it is not enough to evaluate anisotropic strata. Since 2000, with the introduction of directional logging while drilling, a new generation of directional logging tools has been produced. These instruments not only contain axial antennas, but also have inclined and lateral antennas, which can accurately measure the anisotropy, inclination and azimuth angle of the formation, and improve the ability of prediction and geological orientation of the formation interface. In this paper, the law of reflection and transmission of electromagnetic wave in each layer of medium is studied, the analytical expression of electromagnetic wave in dielectric layer is derived, and the amplitude attenuation and phase shift of electromagnetic wave resistivity measured while drilling are calculated. The sensitivity of directional electromagnetic measurement to formation interface is analyzed. At the same time, the relationship between the electromagnetic field excited by the resistivity instrument while drilling and the azimuth variation of the instrument is calculated, and the rule of azimuth resistivity imaging is analyzed. First of all, based on Maxwell equation, the source of logging tool emission is simplified to a magnetic dipole. The electromagnetic field produced in layered strata can be decomposed into linear polarization wave (TE wave) with electric field vector perpendicular to the incident plane and linear polarization wave parallel to the incident plane (TM wave). By studying the law of reflection and transmission of these two kinds of waves in different layers of media, the analytical expressions of magnetic dipole in horizontal layered media are obtained by using the boundary conditions, and the amplitude attenuation and phase shift of electromagnetic waves measured while drilling are calculated based on these expressions. Secondly, three-layer and multi-layer formation models with different thickness of target layer are used to calculate the relationship between the attenuation of directional amplitude and the azimuth of the instrument, and the resolution of azimuth resistivity imaging is analyzed. The results show that when the thickness of the target layer is large, the formation boundary can be determined by imaging, but when the thickness decreases gradually, the imaging effect becomes worse, and it may even misinterpret the real formation condition and affect the logging decision. Finally, according to the expressions of amplitude attenuation and phase shift of electromagnetic wave measurement while drilling, combined with azimuth resistance imaging, the sensitivity of directional electromagnetic measurement to formation interface is analyzed, and the influence of relative dip angle of formation and angle of receiving antenna on electromagnetic measurement is studied. The results show that the larger the coil distance and the thickness of the target layer, the lower the frequency, the greater the difference between the resistivity of the target layer and the surrounding rock, and the larger the detection range of the directional electromagnetic measurement. With the increase of the dip angle of formation and the angle of receiving antenna, the more obvious the change of directional electromagnetic response is near the formation interface, the stronger the sensitivity to the formation interface is. At the same time, the azimuth resolution characteristics of the directional electromagnetic measurement signal are analyzed, and the accurate prediction of the formation interface is realized. The above work and conclusions are of practical significance to azimuth resistivity logging and provide a theoretical basis for the analysis of directional electromagnetic response and azimuth resistance imaging.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.81

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 向裕民;圓環(huán)電流磁場的普遍分布[J];大學(xué)物理;1999年01期

，

本文編號：2447200