# US 2023/0265755 A1 · Detecting downhole drilling events

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- Number: US 2023/0265755 A1
- Document ID: US20230265755A1
- Status: Published application
- Kind: A1
- Application number: 18/006,861
- Filed: 2020-07-28
- Published: 2023-08-24
- Earliest claimed: 2020-07-28
- Assignees: MontanuniversitäT Leoben
- Applicants: MontanuniversitäT Leoben
- Inventors: Asad ELMGERBI; Gerhard THONHAUSER
- Web page: https://patentgrep.com/patent/US20230265755A1

## CPC

- E21B 47/06: Measuring temperature or pressure
- E21B 21/08: Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure (valve arrangements therefor E21B21/10)
- E21B 47/047: Liquid level (measuring depth or liquid level using radioactive markers E21B47/053)
- E21B 47/10: Locating fluid leaks, intrusions or movements
- E21B 2200/20: Computer models or simulations, e.g. for reservoirs under production, drill bits
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

An arrangement for detecting a downhole drilling event during a drilling operation by a drill pipe being partially surrounded by a tubular, wherein the arrangement comprises a sensors holder to be mounted inside of the tubular and to be mounted to surround part of the drill pipe, a plurality of sensors for sensing sensor data indicative of downhole drilling events, wherein at least part of the sensors is mounted on the sensors holder, and a processor configured for processing the sensor data to thereby detect a downhole drilling event.

## Claims

### Claim 1

An arrangement for detecting a downhole drilling event during a drilling operation by a drill pipe being partially surrounded by a tubular, wherein the arrangement comprises:
a sensors holder to be mounted inside of the tubular and to be mounted to surround part of the drill pipe;
a plurality of sensors for sensing sensor data indicative of downhole drilling events, wherein at least part of the sensors is mounted on the sensors holder; and
a processor configured for processing the sensor data to thereby detect a downhole drilling event.

### Claim 2 (depends on 1)

The arrangement of claim 1, comprising a mounting fixture, for example one or more rods, such as at least one of hydraulic rods, mechanically activated rods, and electrically activated rods, connected to the sensors holder and connectable to the tubular.

### Claim 3 (depends on 2)

The arrangement of claim 2, wherein the mounting fixture is connected to a top portion of the sensors holder and connectable to a top portion of the tubular.

### Claim 4 (depends on 2)

The arrangement of claim 2, wherein the mounting fixture and the sensors holder are configured for hanging the sensors holder in the tubular.

### Claim 5 (depends on 2)

The arrangement of claim 2, wherein the mounting fixture is resiliently connected to the sensors holder.

### Claim 6 (depends on 1)

The arrangement of claim 1, comprising one of the following features:
wherein the sensors holder, and for example also a sealing element connected or connectable to the sensors holder, is or are composed of multiple sections, for example two bisections, being selectively openable or closable;
wherein the sensors holder is configured as a single permanently closed sensors holder,
wherein for example at least one of the sensors is mounted at each section of the sensors holder.

### Claim 7

(canceled)

### Claim 8 (depends on 6)

The arrangement of claim 6, comprising a mounting fixture connected to the sensors holder and connectable to the tubular, wherein the mounting fixture is operable for selectively opening or closing the sections of the sensors holder.

### Claim 9 (depends on 6)

The arrangement of claim 6, comprising a biasing mechanism, for example comprising a plurality of magnetic elements mounted on the sections, configured for biasing the sections into the closed configuration.

### Claim 10 (depends on 1)

The arrangement of claim 1, comprising sealing element arranged or arrangeable at the sensors holder for at least partially sealing the sensors holder against drilling fluid.

### Claim 11 (depends on 10)

The arrangement of claim 10, comprising at least one of the following features:
wherein the sealing element is permanently arranged or variably arrangeable at a bottom portion of the sensors holder for example comprising a sealing guide mechanism configured for guiding the sealing element to the bottom portion of the sensors holder by sliding the sealing element downward from a rig floor;
wherein the sealing element has a tapering exterior surface, for example has a conical or frustoconical shape;
wherein the sealing element is made of or with an elastically deformable material, for example rubber;
wherein the sealing element is rotatable with respect to the stationary sensors holder and/or together with the rotatable drill pipe.

### Claim 12

(canceled)

### Claim 13

(canceled)

### Claim 14

(canceled)

### Claim 15

(canceled)

### Claim 16 (depends on 1)

The arrangement of claim 1, comprising at least one of the following features:
wherein the sensors comprise one or multiple level and flow monitor sensors configured for sensing a level of drilling fluid, wherein the processor is for example configured for processing sensor data provided by the level and flow monitor sensor linked with surface data indicative of a surface level;
wherein the sensors comprise at least one of the group consisting of a flowmeter, a temperature sensor, a fluid viscosity sensor, a fluid density sensor, and a pressure sensor;
wherein the sensors holder has a tubular shape;
wherein the downhole drilling event is an undesirable downhole drilling event, for example at least one of the group consisting of losses, kicks, stuck pipe, string failure, and well bore instability;
wherein the processor is configured for controlling or carrying out a computer program of a computer-readable medium.

### Claim 17

(canceled)

### Claim 18

(canceled)

### Claim 19

(canceled)

### Claim 20

(canceled)

### Claim 21

(canceled)

### Claim 22 (depends on 1)

A downhole drilling apparatus, wherein the downhole drilling apparatus comprises:
a rotatable drill pipe configured for downhole drilling in a drill hole and for supplying drilling fluid to the drill hole;
a tubular which partially surrounds the drill pipe; and
an arrangement of claim 1 for detecting a downhole drilling event during a drilling operation by the drill pipe.

### Claim 23 (depends on 22)

The downhole drilling apparatus of claim 22, comprising at least one of the following features:
wherein the tubular is arranged substantially vertically,
wherein the tubular relates to one of the group consisting of a bell nipple, and a marine riser;
wherein the tubular has a circular and/or ring-shaped cross-section;
wherein part of the sensors is built into or planted into the tubular;
comprising a mud return line extending from the tubular in a top portion of the sensors holder;
wherein the downhole drilling apparatus is configured for pumping drilling fluid through the drill pipe into the drill hole and back through an annular gap between the tubular and the sensors holder, and for example into a mud return line;
comprising a mounting fixture, for example one or more rods, such as at least one of hydraulic rods, mechanically activated rods, and electrically activated rods, connected to the tubular and connectable to the sensors holder, wherein for example the mounting fixture is resiliently connected to the tubular.

### Claim 24

(canceled)

### Claim 25

(canceled)

### Claim 26

(canceled)

### Claim 27

(canceled)

### Claim 28

(canceled)

### Claim 29

(canceled)

### Claim 30

(canceled)

### Claim 31 (depends on 22)

A method of detecting a downhole drilling event during a drilling operation by a drill pipe being partially surrounded by a tubular, for example using a downhole drilling apparatus of claim 22, wherein the method comprises:
mounting a sensors holder inside of the tubular and around part of the drill pipe;
arranging at least part of a plurality of sensors on the sensors holder;
operating the sensors for sensing sensor data indicative of downhole drilling events; and
processing the sensor data to thereby detect the downhole drilling event.

### Claim 32

A computer-readable medium, in which a computer program of detecting a downhole drilling event based on sensor data sensed by a plurality of sensors during a drilling operation by a drill pipe being partially surrounded by a tubular is stored, which computer program, when being executed by one or a plurality of processors, is adapted to carry out or control a method, which comprises:
classifying possible downhole drilling events, to be sensed by the sensors, into a plurality of issue classes each being indicative of an assigned issue level of an assigned downhole drilling event;
defining one or more indexes for each of said issue classes, wherein each index corresponds to a parameter, which is detectable by the sensors, in the presence of an assigned downhole drilling event; and
determining a downhole drilling event based on the sensor data, by applying a predictive model for each of the one or more indexes, and using at least one uncertainty window related to the one or more indexes.

### Claim 33

A program element of detecting a downhole drilling event based on sensor data sensed by a plurality of sensors during a drilling operation by a drill pipe being partially surrounded by a tubular, which program element, when being executed by one or a plurality of processors, is adapted to carry out or control a method, which comprises:
classifying possible downhole drilling events, to be sensed by the sensors, into a plurality of issue classes each being indicative of an assigned issue level of an assigned downhole drilling event;
defining one or more indexes for each of said issue classes, wherein each index corresponds to a parameter, which is detectable by the sensors, in the presence of an assigned downhole drilling event; and
determining a downhole drilling event based on the sensor data, by applying a predictive model for each of the one or more indexes, and using at least one uncertainty window related to the one or more indexes.

### Claim 34 (depends on 32)

The computer-readable medium of claim 32, comprising at least one of the following features:
wherein the issue classes comprise a major issue class and a minor issue class which has a lower issue level than the major issue class;
wherein the indexes comprise a main index and a secondary index which has a lower relevance for a possible downhole drilling event assigned to the respective issue class than the main index.

### Claim 35

(canceled)

### Claim 36 (depends on 32)

The computer-readable medium of claim 32, wherein the method comprises determining the downhole drilling event based on a probabilistic model which accepts a potential downhole drilling event as an actual downhole drilling event when a determined probability for the presence of the potential downhole drilling event meets a predetermined confidence criterion, for example exceeds a predetermined confidence level.

### Claim 37 (depends on 36)

The computer-readable medium of claim 36, comprising at least one of the following features:
wherein the predetermined confidence criterion corresponds to at least one Percentile parameter, for example at least one of the group consisting of a P10 parameter and a P90 parameter, a P20 parameter and a P80 parameter, and a P30 parameter and a P70 parameter;
wherein the predetermined confidence criterion corresponds to at least one standard deviation value of a group consisting of 0.5 values standard deviation, 1 value standard deviation, 2 values standard deviation, 3 values standard deviation, 4 values standard deviation, and 5 values standard deviation;
wherein the method comprises building the probabilistic model using at least one statistical reliability parameter of the predictive model, wherein for example the at least one statistical reliability parameter comprises at least one of the group consisting of a root mean square error, an R-squared, an adjusted R-squared, a root mean squared logarithmic error, and a mean absolute error.

### Claim 38

(canceled)

### Claim 39

(canceled)

### Claim 40

(canceled)

### Claim 41 (depends on 32)

The computer-readable medium of claim 32, comprising at least one of the following features:
wherein the method comprises generating the at least one uncertainty window based on a predictive value of the at least one index and based on a probabilistic model; and determining the downhole drilling event based on a comparison of an actual value of the at least one index with the at least one uncertainty window;
wherein the at least one uncertainty window is a multi-dimensional uncertainty window;
wherein the method comprises triggering an action of a group consisting of continue drilling when no undesirable downhole drilling event is detected, stop drilling when an undesirable downhole drilling event is detected, and outputting an alarm when an undesirable downhole drilling event is detected, wherein the method comprises for example: increasing an alarm counter each time a value of an index detected by the sensors is outside of the at least one uncertainty window; and triggering an alarm when a level of the alarm counter exceeds a predetermined threshold value;
wherein the method comprises generating multiple one dimensional uncertainty windows, wherein each uncertainty window corresponds to one confidence criterion;
wherein the method comprises generating multiple multi-dimensional uncertainty windows, wherein each uncertainty window corresponds to one confidence criterion.

### Claim 42

(canceled)

### Claim 43

(canceled)

### Claim 44

(canceled)

### Claim 45

(canceled)

### Claim 46

(canceled)