Motion detection and correction of magnetic resonance data

    公开(公告)号:US10126457B2

    公开(公告)日:2018-11-13

    申请号:US15061636

    申请日:2016-03-04

    摘要: A nuclear magnetic resonance (NMR) apparatus includes a transmitting assembly configured to emit one or more dual-wait-time pulse sequences, and a receiving assembly configured to detect a long-wait-time echo train and a short-wait-time echo train. The apparatus also includes a processor configured to perform at least one of: estimating a difference between the long-wait-time echo train and the short-wait-time echo train to generate a differential echo-train, inverting the differential echo-train into a differential T2 distribution, and detecting a motion artefact in response to determining that the differential echo-train includes a short-T2 porosity fraction that is greater than a threshold value; and inverting two echo trains into two T2 distributions, calculating at least two porosity fractions for each of the two T2 distributions, estimating a shift of a porosity amount between the at least two porosity fractions, and detecting the motion artefact based on the shift.

    METHOD FOR CONSTRUCTING A CONTINUOUS PVT PHASE ENVELOPE LOG

    公开(公告)号:US20180051558A1

    公开(公告)日:2018-02-22

    申请号:US15238424

    申请日:2016-08-16

    IPC分类号: E21B49/00 E21B49/08

    摘要: A method for generating a phase envelope log to characterize a subsurface formation includes drilling the borehole with a drill string, circulating a drilling fluid in the borehole, drawing a fluid sample representing a fluid contained in the subsurface formation, estimating a PVT parameter indicative of an in-situ condition of the subsurface formation from the drawn fluid sample, determining at least two phase envelopes at different depths using the estimated PVT parameter, and creating a phase envelope log formed of a continuous series of phase envelopes using the phase envelopes. A related system includes a drill string, a fluid sampling system, and a processor that estimates a PVT parameter indicative of an in-situ condition of the subsurface formation, determines at least two phase envelopes at different depths using the PVT parameter, and creates the phase envelope log.

    Gas zone evaluation by combining dual wait time NMR data with density data
    8.
    发明授权
    Gas zone evaluation by combining dual wait time NMR data with density data 有权
    通过组合双等时时间NMR数据与密度数据进行气体区评估

    公开(公告)号:US06331775B1

    公开(公告)日:2001-12-18

    申请号:US09396286

    申请日:1999-09-15

    IPC分类号: G01V300

    CPC分类号: G01V11/00 G01N24/081 G01V3/32

    摘要: A method for acquiring nuclear magnetic resonance measurements of a medium uses a modified CPMG pulse sequence wherein the refocusing pulses may be optiimized, having a shorter duration than a 180° pulse. Data are acquired in gas reservoirs using two different wait times, both of which are sufficient to polarize the liquid in the reservoir to a known exteny, preferably 100%, while the amount of polarization of the gas in the reservoir is substantially different for the two wait times. Data from the dual wait time NMR pulse sequences give two different apparent porosities of the formation. A third apparent porosity is obtained from density measurements. Combining these three apparent porosities with a temperature measurement and empirical relations between various petrophysical parameters gives the true porosity, the gas density, the gas hydrogen index and the spin-lattice relaxation time of the gas at a single depth. In an alternate embodiment of the invention, apparent porosity measurements made at a plurality of depths within a connected gas reservoir are averaged and, in combination with temperature measurements in the reservoir, the same petrophysical parameters are obtained with the gas properties being constant, thus reducing numerical instability in the solution of the equations relating the petrophysical parameters.

    摘要翻译: 用于获取介质的核磁共振测量的方法使用修改的CPMG脉冲序列,其中重聚焦脉冲可被优化,具有比180°脉冲更短的持续时间。 使用两个不同的等待时间在气藏中获取数据,这两个等待时间都足以将储层中的液体极化到已知的范围,优选为100%,同时储存器中的气体的极化量对于两个 等待时间 来自双等待时间NMR脉冲序列的数据给出了两个不同的表观孔隙度的形成。 从密度测量获得第三表观孔隙率。 将这三种表观孔隙度与温度测量和各种岩石物理参数之间的经验关系相结合,可以获得真实的孔隙度,气体密度,气体氢指数和单一深度气体的自旋晶格弛豫时间。 在本发明的替代实施例中,在连接的气体储存器内的多个深度处进行的表观孔隙度测量被平均,并且与储层中的温度测量结合,获得相同的岩石物理参数,其中气体性质是恒定的,从而减少 与岩石物理参数有关的方程解的数值不稳定性。

    Method for constructing a continuous PVT phase envelope log

    公开(公告)号:US10598010B2

    公开(公告)日:2020-03-24

    申请号:US15238424

    申请日:2016-08-16

    IPC分类号: E21B49/00 E21B49/08

    摘要: A method for generating a phase envelope log to characterize a subsurface formation includes drilling the borehole with a drill string, circulating a drilling fluid in the borehole, drawing a fluid sample representing a fluid contained in the subsurface formation, estimating a PVT parameter indicative of an in-situ condition of the subsurface formation from the drawn fluid sample, determining at least two phase envelopes at different depths using the estimated PVT parameter, and creating a phase envelope log formed of a continuous series of phase envelopes using the phase envelopes. A related system includes a drill string, a fluid sampling system, and a processor that estimates a PVT parameter indicative of an in-situ condition of the subsurface formation, determines at least two phase envelopes at different depths using the PVT parameter, and creates the phase envelope log.

    FORMATION EVALUATION UTILIZING DUAL WAIT TIME NUCLEAR MAGNETIC RESONANCE
    10.
    发明申请
    FORMATION EVALUATION UTILIZING DUAL WAIT TIME NUCLEAR MAGNETIC RESONANCE 审中-公开
    使用双等待时间核磁共振的形成评估

    公开(公告)号:US20160116629A1

    公开(公告)日:2016-04-28

    申请号:US14920436

    申请日:2015-10-22

    IPC分类号: G01V3/32

    CPC分类号: G01V3/32 G01V3/38 G01V3/40

    摘要: A system for measuring a property of fluid in an earth formation includes a downhole tool disposed in a borehole and configured to be movable within the borehole and a nuclear magnetic resonance (NMR) measurement device including a transmitter configured to emit at least two pulse trains of magnetic energy into the earth formation and a detector configured to detect a long-TW echo train and a short-TW echo train resulting from the at least two pulse trains. The system also includes a processor configured to combine the information from the at least two pulse trains and a rate of penetration of the downhole tool to form a measurement of the property.

    摘要翻译: 用于测量地层中的流体性质的系统包括设置在钻孔中并被配置为可在钻孔内移动的井下工具,以及包括发射器的核磁共振(NMR)测量装置,所述核磁共振(NMR)测量装置被配置为发射至少两个脉冲列 磁能进入地层,以及检测器,被配置为检测长TW回波串和由至少两个脉冲序列产生的短TW回波串。 该系统还包括处理器,该处理器被配置为组合来自至少两个脉冲序列的信息和井下工具的穿透速率以形成该属性的测量。