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CN-121986276-A - Geosteering method based on formation dielectric properties estimated from measurement while drilling measurements

CN121986276ACN 121986276 ACN121986276 ACN 121986276ACN-121986276-A

Abstract

A drilling system performs a method for identifying a producing zone in a formation. The processor measures a first dielectric constant of the formation at a selected depth or depth interval using first electromagnetic waves or signals transmitted through the formation at a first frequency at the selected depth or depth interval in a borehole in the formation, measures a second dielectric constant of the formation at the selected depth or depth interval using second electromagnetic waves or signals transmitted through the formation at a second frequency at the selected depth or depth interval in the borehole in the formation, and identifies a producing layer in the formation based on the first dielectric constant at the selected depth or depth interval and the second dielectric constant at the selected depth or depth interval.

Inventors

  • S. M. Al Ophi
  • ZHANG JUN
  • Stuart Blake Brazil

Assignees

  • 贝克休斯油田作业有限责任公司

Dates

Publication Date
20260505
Application Date
20241106
Priority Date
20231106

Claims (15)

  1. 1. A method for identifying a producing zone in a formation (104), the method characterized by: measuring a first dielectric constant of a formation (104) at a selected depth or depth interval in a borehole (102) in the formation (104) using a first electromagnetic wave or signal transmitted through the formation (104) at the first frequency; measuring a second dielectric constant of the formation (104) at the selected depth or depth interval using a second electromagnetic wave or signal transmitted through the formation (104) at a second frequency at the selected depth or depth interval in the borehole (102) in the formation (104), and The pay zone is identified based on the first dielectric constant at the selected depth or depth interval and the second dielectric constant at the selected depth or depth interval.
  2. 2. The method of claim 1, further characterized by determining a permittivity slope based on the first permittivity and the second permittivity, and identifying the pay zone based on the permittivity slope.
  3. 3. The method of claim 2, further characterized by identifying the producing zone based on a comparison of the permittivity slope with a permittivity slope threshold.
  4. 4. The method of claim 1, wherein the producing zone is identified using a processor (124) in the borehole (102).
  5. 5. The method of claim 1, wherein the first frequency or the second frequency is in a range of about 1 kilohertz (kHz) to about 30 megahertz (Mhz).
  6. 6. The method of claim 5, wherein the first frequency or the second frequency is in a range of about 100 kilohertz (kHz) to about 10 megahertz (Mhz).
  7. 7. The method of claim 3, further characterized by determining the dielectric constant slope threshold using measurements obtained in a first section of the borehole (102), and wherein the selected depth or depth interval is located in a second section of the borehole (102) different from the first section.
  8. 8. The method of claim 1, further characterized by steering a drill string (106) based on the identification of the producing zone.
  9. 9. A drilling system (100), the drilling system characterized by: a processor (124) configured to: Measuring a first dielectric constant of a formation (104) at a selected depth or depth interval in a borehole (102) in the formation (104) using a first electromagnetic wave or signal transmitted through the formation (104) at the first frequency; measuring a second dielectric constant of the formation (104) at the selected depth or depth interval using a second electromagnetic wave or signal transmitted through the formation (104) at a second frequency at the selected depth or depth interval in the borehole (102) in the formation (104), and An oil producing layer in the formation (104) is identified based on the first dielectric constant at the selected depth or depth interval and the second dielectric constant at the selected depth or depth interval.
  10. 10. The drilling system (100) of claim 9, wherein the processor (124) is further configured to determine a permittivity slope based on the first permittivity and the second permittivity, and identify the producing layer based on the permittivity slope.
  11. 11. The drilling system (100) of claim 10, wherein the processor (124) is further configured to identify the producing zone based on a comparison of the permittivity slope to a permittivity slope threshold.
  12. 12. The drilling system (100) according to claim 9, wherein the processor (124) is located in the borehole (102).
  13. 13. The drilling system (100) of claim 9, wherein the first frequency or the second frequency is in the range of (i) about 1 kilohertz (kHz) to about 30 megahertz (Mhz), and (ii) about 100 kilohertz (kHz) to about 10 megahertz (Mhz).
  14. 14. The drilling system (100) according to claim 11, wherein the processor (124) is further configured to determine the dielectric constant slope threshold using measurements obtained in a first section of the borehole (102), and wherein the selected depth or depth interval is located in a second section of the borehole (102) different from the first section.
  15. 15. The drilling system (100) according to claim 9, wherein the processor (124) is further configured to steer the drill string (106) based on the identification of the producing zone.

Description

Geosteering method based on formation dielectric properties estimated from measurement while drilling measurements Cross Reference to Related Applications The present application claims the benefit of earlier filing date of U.S. provisional application serial No. 63/547,427 filed on month 11 and 6 of 2023, the entire disclosure of which is incorporated herein by reference. Background In the resource recovery industry, drill strings are used to drill holes in formations and locate the presence of hydrocarbons in formations. The drill string may have a logging while drilling tool that includes various sensors that may be used to determine formation parameters. In particular, a power tool may be used to measure formation resistivity, which may be used to determine the depth at which hydrocarbons are present in the formation. However, for certain formations, the resistivity is not a useful parameter for determining whether hydrocarbons are present, particularly where the resistivity difference between hydrocarbon-bearing and non-hydrocarbon-bearing zones is minimal or a priori knowledge of formation properties is unknown, such as fluid resistivity and formation porosity. It is therefore desirable to provide a method for employing a power tool that can be used to determine parameters other than resistivity that can be used to identify hydrocarbons in these formations. Disclosure of Invention Disclosed herein is a method for identifying a pay zone in a subterranean formation. A first dielectric constant of the formation at a selected depth or depth interval is measured using a first electromagnetic wave or signal transmitted through the formation at a first frequency at the selected depth or depth interval in a borehole in the formation. A second dielectric constant of the formation at a selected depth or depth interval is measured using a second electromagnetic wave or signal transmitted through the formation at a second frequency at the selected depth or depth interval in a borehole in the formation. The pay zone is identified based on a first dielectric constant at a selected depth or depth interval and a second dielectric constant at the selected depth or depth interval. A drilling system including a processor is disclosed herein. The processor is configured to measure a first dielectric constant of a formation at a selected depth or depth interval in a borehole in the formation using a first electromagnetic wave or signal transmitted through the formation at the selected depth or depth interval at a first frequency, measure a second dielectric constant of the formation at the selected depth or depth interval using a second electromagnetic wave or signal transmitted through the formation at the selected depth or depth interval in the borehole in the formation at a second frequency, and identify an oil production layer in the formation based on the first dielectric constant at the selected depth or depth interval and the second dielectric constant at the selected depth or depth interval. Drawings The following description should not be taken as limiting in any way. Referring to the drawings, like elements are numbered alike: FIG. 1 illustrates a drilling system in an exemplary embodiment; FIG. 2 illustrates a power tool of a drill string of the drilling system in an exemplary embodiment; 3A-3D illustrate exemplary logs that may be obtained from a formation using formation sensors of a drill string; FIG. 4 shows a graph of dielectric constant values versus frequency for different depths in a borehole; FIGS. 5A-5D show various logs obtained from a formation for illustrative purposes, where resistivity is not suitable for determining whether hydrocarbons are present; FIG. 6 is a flow chart of a method for detecting hydrocarbon pay zones at a depth in a borehole, and FIG. 7 is a flow chart of another method for detecting hydrocarbons at a depth in a borehole. Detailed Description Specific embodiments of one or more embodiments of the apparatus and methods disclosed herein are presented by way of example and not limitation with reference to the figures. Referring to fig. 1, a drilling system 100 is disclosed in an exemplary embodiment. The drilling system 100 includes a borehole 102 penetrating a subterranean formation 104. A drill string 106 is disposed within the borehole 102. The drill string 106 includes tubulars 108 extending from a drilling platform 110 at a surface location 112. The tubular 108 includes a Bottom Hole Assembly (BHA) 114 that includes a steering unit 116, a drill bit 118, and one or more formation sensors 120 for measuring various characteristics of the formation. The formation sensors 120 may include power tools for measuring electrical characteristics (such as resistivity, conductivity, permittivity, etc.) of the formation 104. Other formation sensors may include, for example, gamma ray sensors. Controller 122 receives data from formation sensors and determines the location of hydrocarbons i