# US 10,370,911 B2 · Methods and systems for drilling boreholes in earth formations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,911 B2 - Document ID: US10370911B2 - Status: Granted - Kind: B2 - Application number: 15/373,036 - Filed: 2016-12-08 - Published: 2018-06-14 - Granted: 2019-08-06 - Earliest claimed: 2016-12-08 - Assignees: Baker Hughes Incorporated; BP Exploration Operating Company Limited - Applicants: Baker Hughes Incorporated; BP Exploration Operating Company Limited - Inventors: David A. Curry; Rudolf Carl Pessier; Reed W. Spencer; Andrea Kuesters; John Wingate - Web page: https://patentgrep.com/patent/US10370911B2 ## CPC - E21B 19/008: {Winding units, specially adapted for drilling operations} - 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 47/04: Measuring depth or liquid level - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract Methods of drilling earth formations may involve removing a portion of an underlying earth formation utilizing cutting elements of an earth-boring drill bit. A rotational speed of the drill string may be sensed utilizing a first sensor. A rate of penetration of the drill string during advancement of the earth-boring drill bit may be sensed utilizing a second sensor. An instantaneous average depth of cut of cutting elements of the earth-boring drill bit may be determined utilizing a control unit to calculate the instantaneous average depth of cut based on a sensed rotational speed of the drill string and a sensed speed of advancement of the drill string. The weight on the earth-boring drill bit may be increased utilizing the drawworks when the instantaneous average depth of cut is less than the predetermined minimum depth of cut. ## Claims ### Claim 1 A system for drilling into an earth formation, comprising: an earth-boring drill bit comprising fixed cutting elements configured to engage with and remove an underlying earth formation; a drill string configured to be connected to the earth-boring drill bit to transfer longitudinal and rotational loads to the earth-boring drill bit; a drawworks configured to suspend the earth-boring drill bit and the drill string and to apply weight to the earth-boring drill bit via the drill string to advance the earth-boring drill bit into the underlying earth formation; a first sensor operatively associated with the drill string, the first sensor configured to sense a rotational speed of the drill string; a second sensor operatively associated with the drill string, the second sensor configured to sense a rate of penetration of the drill string during advancement of the earth-boring drill bit; and a control unit operatively connected to the first and second sensors and to the drawworks, the control unit comprising a processing unit and non-transitory memory operatively connected to the processing unit, the processing unit programmed to: determine an instantaneous average depth of cut of the cutting elements of the earth-boring drill bit utilizing a sensed rotational speed of the drill string and a sensed speed of advancement of the drill string utilizing the following algorithm: DOC = ROP RPM × Redundancy wherein DOC is the instantaneous average depth of cut, ROP is the sensed rate of penetration, RPM is the sensed rotational speed of the drill string, and Redundancy is a sum of diameters of the cutting elements of the earth-boring drill bit divided by a radius of the earth-boring drill bit; compare the instantaneous average depth of cut to a predetermined minimum depth of cut stored in the nontransitory memory; and cause the drawworks to increase weight on the earth-boring drill bit when the instantaneous average depth of cut is less than the predetermined minimum depth of cut. ### Claim 2 (depends on 1) The system of claim 1, further comprising a third sensor operatively associated with the drawworks, the third sensor configured to sense the weight applied to the earth-boring drill bit via the drawworks and drill string, the third sensor operatively connected to the control unit. ### Claim 3 (depends on 2) The system of claim 2, wherein the processing unit is further programmed to: compare a sensed weight applied to the earth-boring drill bit to a predetermined minimum weight applicable to the earth-boring drill bit stored in the nontransitory memory; and cause the drawworks to increase weight on the earth-boring drill bit when the sensed weight applied to the earth-boring drill bit is less than the predetermined minimum weight applicable to the earth-boring drill bit. ### Claim 4 (depends on 3) The system of claim 3, wherein the processing unit is further programmed to: compare the sensed weight applied to the earth-boring drill bit to a predetermined maximum weight applicable to the earth-boring drill bit stored in the nontransitory memory; and cause the drawworks to stop increasing weight on the earth-boring drill bit when the sensed weight applied to the earth-boring drill bit is proximate the predetermined maximum weight applicable to the earth-boring drill bit. ### Claim 5 (depends on 2) The system of claim 2, wherein the third sensor comprises a strain gauge. ### Claim 6 (depends on 1) The system of claim 1, wherein the first sensor comprises a magnetoresistive sensor, a reflective sensor, an interrupter sensor, or an optical encoder. ### Claim 7 (depends on 1) The system of claim 1, wherein the second sensor comprises a potentiometer, a linear variable differential transformer, an inductive proximity sensor, or an incremental encoder. ### Claim 8 (depends on 1) The system of claim 1, wherein the predetermined minimum depth of cut is about 0.02 inch or more. ### Claim 9 A method of drilling an earth formation, comprising: removing a portion of an underlying earth formation utilizing fixed cutting elements on an earth-boring drill bit; applying weight to the earth-boring drill bit utilizing a drawworks connected to the earth-boring drill bit via a drill string to advance the earth-boring drill bit into the underlying earth formation; sensing a rotational speed of the drill string utilizing a first sensor operatively associated with the drill string; sensing a rate of penetration of the drill string during advancement of the earth-boring drill bit utilizing a second sensor operatively associated with the drill string; determining an instantaneous average depth of cut of cutting elements of the earth-boring drill bit utilizing a control unit operatively connected to the first and second sensors to calculate the instantaneous average depth of cut based on a sensed rotational speed of the drill string and a sensed speed of advancement of the drill string utilizing the following algorithm: DOC = ROP RPM × Redundancy wherein DOC is the instantaneous average depth of cut, ROP is the sensed rate of penetration, RPM is the sensed rotational speed of the drill string, and Redundancy is a sum of diameters of the cutting elements of the earth-boring drill bit divided by a radius of the earth-boring drill bit, and wherein the control unit comprises a processing unit and non-transitory memory operatively connected to the processing unit; comparing the instantaneous average depth of cut to a predetermined minimum depth of cut stored in the non-transitory memory utilizing the control unit; and causing the drawworks to increase the weight on the earth-boring drill bit when the instantaneous average depth of cut is less than the predetermined minimum depth of cut. ### Claim 10 (depends on 9) The method of claim 9, further comprising displaying an instruction to increase the weight on the earth-boring drill bit utilizing an electronic display operatively connected to the control unit when the instantaneous average depth of cut is less than the predetermined minimum depth of cut. ### Claim 11 (depends on 10) The method of claim 10, wherein causing the drawworks to increase weight on the earth-boring drill bit comprises a drilling operator operating the drawworks to increase weight on the earth-boring drill bit. ### Claim 12 (depends on 10) The method of claim 10, wherein displaying the instruction to increase the weight on the earth-boring drill bit utilizing the electronic display comprises displaying a first color in a designated area on the electronic display when the instantaneous average depth of cut is greater than the predetermined minimum depth of cut and displaying a second, different color in the designated area on the electronic display when the instantaneous average depth of cut is less than the predetermined minimum depth of cut. ### Claim 13 (depends on 9) The method of claim 9, further comprising sensing the weight applied to the earth-boring drill bit via the drawworks and drill string utilizing a third sensor operatively associated with the drawworks, the third sensor operatively connected to the control unit. ### Claim 14 (depends on 13) The method of claim 13, further comprising: comparing a sensed weight applied to the earth-boring drill bit to a predetermined minimum weight applicable to the earth-boring drill bit stored in the non-transitory memory; and causing the drawworks to increase weight on the earth-boring drill bit when the sensed weight applied to the earth-boring drill bit is less than the predetermined minimum weight applicable to the earth-boring drill bit. ### Claim 15 (depends on 13) The method of claim 13, further comprising: comparing the sensed weight applied to the earth-boring drill bit to a predetermined maximum weight applicable to the earth-boring drill bit stored in the non-transitory memory; and causing the drawworks to stop increasing weight on the earth-boring drill bit when the sensed weight applied to the earth-boring drill bit is proximate the predetermined maximum weight applicable to the earth-boring drill bit. ### Claim 16 (depends on 15) The method of claim 15, wherein causing the drawworks to stop increasing weight on the earth-boring drill bit when the sensed weight applied to the earth-boring drill bit is proximate the predetermined maximum weight applicable to the earth-boring drill bit comprises causing the drawworks to stop increasing weight on the earth-boring drill bit when the sensed weight applied to the earth-boring drill bit is proximate at least one of a weight at which the drill string will buckle, a weight at which the earth-boring drill bit will exhibit stick-slip behavior, a weight at which a torque limit of a rotational driver of the drill string will be exceeded, and a weight at which the earth-boring drill bit or any other component of the drill string will experience catastrophic failure. ### Claim 17 (depends on 14) The method of claim 14, further comprising simulating drilling the earth formation to generate the predetermined minimum weight applicable to the earth-boring drill bit by iteratively finding a lowest weight applied to the earth-boring drill bit to achieve the predetermined minimum depth of cut. ### Claim 18 (depends on 9) The method of claim 9, wherein causing the drawworks to increase weight on the earth-boring drill bit comprises the control unit automatically operating the drawworks to increase the weight on the earth-boring drill bit.