# US 11,078,785 B1 · Real-time well drilling evaluation systems and methods

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- Number: US 11,078,785 B1
- Document ID: US11078785B1
- Status: Granted
- Kind: B1
- Application number: 16/903,462
- Filed: 2020-06-17
- Granted: 2021-08-03
- Earliest claimed: 2020-06-17
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: Anas Almarzooq; Charles Bradford; Mustafa Abdulmohsin
- Web page: https://patentgrep.com/patent/US11078785B1

## CPC

- E21B 49/003: {by analysing drilling variables or conditions (E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00)}
- E21B 44/00: Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
- E21B 45/00: Measuring the drilling time or rate of penetration
- E21B 49/02: by mechanically taking samples of the soil
- E21B 25/00: Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors (core bits E21B10/02)
- G01N 33/24: Earth materials (G01N33/42 takes precedence)
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Provided are techniques for drilling hydrocarbon wells based on evaluation of penetrated formation rock that include obtaining historical drilling data for one or more wells, determining a rock type mapping based on the historical drilling data, obtaining current drilling data for a well, determining, based on the current drilling data, a current rock identification (or “ROCKID”), and determining, based on the rock type mapping and the current rock identification, a rock type encountered by a drill bit drilling the well, where drilling parameters can be adjusted based on the rock type.

## Claims

### Claim 1

A hydrocarbon well drilling system, comprising:
a well drilling system configured to drill a wellbore of a hydrocarbon well into a subsurface formation, the well drilling system comprising:
a drill string comprising:
a drill bit;
drill pipe; and
drilling sensors configured to sense characteristics of a drilling operation conducted by the well drilling system;
a well control system configured to perform the following operations:
obtaining, by way of the drilling sensors, drilling data that is indicative of characteristics of the drilling operation, the drilling data comprising:
rate of penetration data that is indicative of rate of penetration of the drill bit into the subsurface formation;
weight on bit data that is indicative of weight acting on the drill bit;
rotation data that is indicative of rotational speed of the drill pipe;
torque data that is indicative of a torque acting on the drill pipe;
fluid circulation data that is indicative of rate of drilling fluid circulation;
surface gas data that is indicative of concentrations of one or more surface gases produced;
determining, based on the drilling data, the following drilling characteristics for a given point in time:
an observed rate of penetration of the drill bit at the given point in time (ROPi) determined based on the rate of penetration data,
a product of observed concentrations of one or more surface gases produced at the given point in time (Cprodi) determined based on the surface gas data;
a sum of observed concentrations of one or more surface gases produced at the given point in time (Csumi) determined based on the surface gas data;
an observed weight acting on the drill bit at the given point in time (WOBi determined based on the weight on bit data;
an observed torque acting on the drill pipe at the given point in time (Ti) is determined based on the torque data;
an observed rotational speed of the drill pipe at the given point in time (RPMi) determined based on the rotation data; and
an observed rate of drilling fluid circulation at the given point in time (FLWPMPSi) determined based on the fluid circulation data;
applying the drilling data to the following rock identification relationship to determine a rock identification value (ROCKIDi) that is indicative of a type of rock engaged by the drill bit at the given point in time:
ROCKID
i
=
B
*
(
log
1
⁢
0
⁡
(
ROP
i
ROPB
i
)
)
*
C
prod
i
(
C
sum
i
*
A
)
*
WOB
i
*
T
i
*
R
⁢
P
⁢
M
i
*
FLWPMP
⁢
S
i
D
⁢
C
⁢
F
where:
ROPBi is a base rate of penetration of the drill bit,
DCF is a drilling calibration factor, and
A and B are calibration constants associated with the subsurface formation;
determining, based on the ROCKIDi, a type of rock engaged by the drill bit at the given point in time;
determining, based on the type of rock determined, a drilling operation parameter; and
conducting a drilling operation in accordance with the drilling operation parameter.

### Claim 2 (depends on 1)

The system of claim 1, the operations further comprising:
determining a rock type mapping that maps ROCKID values to associated types of rocks,
wherein the rock type mapping maps the ROCKIDi to the type of rock, and
wherein the type of rock engaged by the drill bit at the given point in time is determined based the mapping of the ROCKIDi to the type of rock.

### Claim 3 (depends on 2)

The system of claim 2, wherein determining a rock type mapping comprises:
identifying drilling parameters associated with known rock types;
applying the drilling parameters associated with known rock types to the rock identification relationship to generate ROCKID values; and
associating, based on the ROCKID values generated and the associated known rock types, groups of ROCKID values with respective ones of the known rock types.

### Claim 4 (depends on 1)

The system of claim 1, the operations further comprising determining the drilling calibration factor (DCF) based on a comparison of determined ROCKID values for one or more points in time to known types of rocks encountered during drilling at the one or more points in time.

### Claim 5 (depends on 4)

The system of claim 4, wherein the known types of rocks encountered during drilling at the one or more points in time are determined based on inspection of formation rock encountered by the drill bit at the one or more points in time.

### Claim 6 (depends on 5)

The system of claim 5, wherein the inspection comprises physical inspection of one or more samples of rock extracted from the location of the drill bit at the one or more points in time.

### Claim 7 (depends on 5)

The system of claim 5, wherein the inspection comprises inspection of well logs of a depth interval that comprises the location of the drill bit at the one or more points in time.

### Claim 8 (depends on 1)

The system of claim 1, wherein the drilling operation parameter comprises a time to conduct a pull out of hole operation to inspect the drill bit, and wherein conducting a drilling operation in accordance with the drilling operation parameter comprises conducting the pull out of hole operation to inspect the drill bit.

### Claim 9 (depends on 1)

The system of claim 1, wherein the drilling operation parameter comprises a time to conduct a coring operation, and wherein conducting a drilling operation in accordance with the drilling operation parameter comprises conducting the coring operation.

### Claim 10

A method of drilling a hydrocarbon well, the method comprising:
obtaining, by way of the drilling sensors, drilling data that is indicative of characteristics of drilling a wellbore of a hydrocarbon well into a subsurface formation by way of a drilling system that includes a drill string that comprises a drill bit, drill pipe and
the drilling sensors, the drilling data comprising:
rate of penetration data that is indicative of rate of penetration of the drill bit into the subsurface formation;
weight on bit data that is indicative of weight acting on the drill bit;
rotation data that is indicative of rotational speed of the drill pipe;
torque data that is indicative of a torque acting on the drill pipe;
fluid circulation data that is indicative of rate of drilling fluid circulation;
surface gas data that is indicative of concentrations of one or more surface gases produced;
determining, based on the drilling data, the following drilling characteristics for a given point in time:
an observed rate of penetration of the drill bit at the given point in time (ROPi) determined based on the rate of penetration data;
a product of observed concentrations of one or more surface gases produced at the given point in time (Cprodi) determined based on the surface gas data;
a sum of observed concentrations of one or more surface gases produced at the given point in time (Csumi) determined based on the surface gas data;
an observed weight acting on the drill bit at the given point in time (WOBi) determined based on the weight on bit data;
an observed torque acting on the drill pipe at the given point in time (Ti) is determined based on the torque data;
an observed rotational speed of the drill pipe at the given point in time (RPMi) determined based on the rotation data; and
an observed rate of drilling fluid circulation at the given point in time (FLWPMPSi) determined based on the fluid circulation data;
applying the drilling data to the following rock identification relationship to determine a rock identification value (ROCKIDi) that is indicative of a type of rock engaged by the drill bit at the given point in time:
ROCKID
i
=
B
*
(
log
1
⁢
0
⁡
(
ROP
i
ROPB
i
)
)
*
C
prod
i
(
C
sum
i
*
A
)
*
WOB
i
*
T
i
*
R
⁢
P
⁢
M
i
*
FLWPMP
⁢
S
i
D
⁢
C
⁢
F
where:
ROPBi is a base rate of penetration of the drill bit,
DCF is a drilling calibration factor, and
A and B are calibration constants associated with the subsurface formation;
determining, based on the ROCKIDi, a type of rock engaged by the drill bit at the given point in time;
determining, based on the type of rock determined, a drilling operation parameter; and
conducting a drilling operation in accordance with the drilling operation parameter.

### Claim 11 (depends on 10)

The method of claim 10, further comprising:
determining a rock type mapping that maps ROCKID values to associated types of rocks,
wherein the rock type mapping maps the ROCKIDi to the type of rock, and
wherein the type of rock engaged by the drill bit at the given point in time is determined based the mapping of the ROCKIDi to the type of rock.

### Claim 12 (depends on 11)

The method of claim 11, wherein determining a rock type mapping comprises:
identifying drilling parameters associated with known rock types;
applying the drilling parameters associated with known rock types to the rock identification relationship to generate ROCKID values; and
associating, based on the ROCKID values generated and the associated known rock types, groups of ROCKID values with respective ones of the known rock types.

### Claim 13 (depends on 10)

The method of claim 10, further comprising determining the drilling calibration factor (DCF) based on a comparison of determined ROCKID values for one or more points in time to known types of rocks encountered during drilling at the one or more points in time.

### Claim 14 (depends on 13)

The method of claim 13, wherein the known types of rocks encountered during drilling at the one or more points in time are determined based on inspection of formation rock encountered by the drill bit at the one or more points in time.

### Claim 15 (depends on 14)

The method of claim 14, wherein the inspection comprises physical inspection of one or more samples of rock extracted from the location of the drill bit at the one or more points in time.

### Claim 16 (depends on 14)

The method of claim 14, wherein the inspection comprises inspection of well logs of a depth interval that comprises the location of the drill bit at the one or more points in time.

### Claim 17 (depends on 10)

The method of claim 10, wherein the drilling operation parameter comprises a time to conduct a pull out of hole operation to inspect the drill bit, and wherein conducting a drilling operation in accordance with the drilling operation parameter comprises conducting the pull out of hole operation to inspect the drill bit.

### Claim 18 (depends on 10)

The method of claim 10, wherein the drilling operation parameter comprises a time to conduct a coring operation, and wherein conducting a drilling operation in accordance with the drilling operation parameter comprises conducting the coring operation.

### Claim 19

Non-transitory computer readable storage medium comprising program instructions stored thereon that are executable by a computer processer to perform the following operations for drilling a hydrocarbon well:
obtaining, by way of drilling sensors, drilling data that is indicative of characteristics of drilling a wellbore of a hydrocarbon well into a subsurface formation by way of a drilling system that includes a drill string that comprises a drill bit, drill pipe and
the drilling sensors, the drilling data comprising:
rate of penetration data that is indicative of rate of penetration of the drill bit into the subsurface formation;
weight on bit data that is indicative of weight acting on the drill bit;
rotation data that is indicative of rotational speed of the drill pipe;
torque data that is indicative of a torque acting on the drill pipe;
fluid circulation data that is indicative of rate of drilling fluid circulation;
surface gas data that is indicative of concentrations of one or more surface gases produced;
determining, based on the drilling data, the following drilling characteristics for a given point in time:
an observed rate of penetration of the drill bit at the given point in time (ROPi) determined based on the rate of penetration data,
a product of observed concentrations of one or more surface gases produced at the given point in time (Cprodi) determined based on the surface gas data;
a sum of observed concentrations of one or more surface gases produced at the given point in time (Csumi) determined based on the surface gas data;
an observed weight acting on the drill bit at the given point in time (WOBi) determined based on the weight on bit data;
an observed torque acting on the drill pipe at the given point in time (Ti) is determined based on the torque data;
an observed rotational speed of the drill pipe at the given point in time (RPMi) determined based on the rotation data; and
an observed rate of drilling fluid circulation at the given point in time (FLWPMPSi) determined based on the fluid circulation data;
applying the drilling data to the following rock identification relationship to determine a rock identification value (ROCKIDi) that is indicative of a type of rock engaged by the drill bit at the given point in time:
ROCKID
i
=
B
*
(
log
1
⁢
0
⁡
(
ROP
i
ROPB
i
)
)
*
C
prod
i
(
C
sum
i
*
A
)
*
WOB
i
*
T
i
*
R
⁢
P
⁢
M
i
*
FLWPMP
⁢
S
i
D
⁢
C
⁢
F
where:
ROPBi is a base rate of penetration of the drill bit,
DCF is a drilling calibration factor, and
A and B are calibration constants associated with the subsurface formation;
determining, based on the ROCKIDi, a type of rock engaged by the drill bit at the given point in time;
determining, based on the type of rock determined, a drilling operation parameter; and
conducting a drilling operation in accordance with the drilling operation parameter.

### Claim 20 (depends on 19)

The medium of claim 19, the operations further comprising:
determining a rock type mapping that maps ROCKID values to associated types of rocks,
wherein the rock type mapping maps the ROCKIDi to the type of rock, and
wherein the type of rock engaged by the drill bit at the given point in time is determined based the mapping of the ROCKIDi to the type of rock.

### Claim 21 (depends on 20)

The medium of claim 20, wherein determining a rock type mapping comprises:
identifying drilling parameters associated with known rock types;
applying the drilling parameters associated with known rock types to the rock identification relationship to generate ROCKID values; and
associating, based on the ROCKID values generated and the associated known rock types, groups of ROCKID values with respective ones of the known rock types.

### Claim 22 (depends on 19)

The medium of claim 19, the operations further comprising:
determining the drilling calibration factor (DCF) based on a comparison of determined ROCKID values for one or more points in time to known types of rocks encountered during drilling at the one or more points in time.

### Claim 23 (depends on 22)

The medium of claim 22, wherein the known types of rocks encountered during drilling at the one or more points in time are determined based on inspection of formation rock encountered by the drill bit at the one or more points in time.

### Claim 24 (depends on 23)

The medium of claim 23, wherein the inspection comprises physical inspection of one or more samples of rock extracted from the location of the drill bit at the one or more points in time.

### Claim 25 (depends on 23)

The medium of claim 23, wherein the inspection comprises inspection of well logs of a depth interval that comprises the location of the drill bit at the one or more points in time.

### Claim 26 (depends on 19)

The medium of claim 19, wherein the drilling operation parameter comprises a time to conduct a pull out of hole operation to inspect the drill bit, and wherein conducting a drilling operation in accordance with the drilling operation parameter comprises conducting the pull out of hole operation to inspect the drill bit.

### Claim 27 (depends on 19)

The medium of claim 19, wherein the drilling operation parameter comprises a time to conduct a coring operation, and wherein conducting a drilling operation in accordance with the drilling operation parameter comprises conducting the coring operation.