# US 9,753,170 B2 · Sourceless density determination apparatus, methods, and systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,753,170 B2 - Document ID: US9753170B2 - Status: Granted - Kind: B2 - Application number: 14/650,808 - Filed: 2012-12-31 - Published: 2015-12-31 - Granted: 2017-09-05 - Earliest claimed: 2012-12-31 - Assignees: Halliburton Energy Services, Inc. - Applicants: Halliburton Energy Services, Inc. - Inventors: Batakrishna Mandal; Arthur Cheng; Nigel Clegg; Jennifer Anne Market - Web page: https://patentgrep.com/patent/US9753170B2 ## CPC - G01V 1/50: Analysing data - G01V 1/306: {for determining physical properties of the subsurface, e.g. impedance, porosity or attenuation profiles} - G01V 1/44: using generators and receivers in the same well (G01V1/52 takes precedence) - G01V 2210/6222: Velocity; travel time - G01V 2210/6224: Density - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) ## Abstract In some embodiments, an apparatus and a system, as well as a method and an article, may operate to determine a compressional velocity (CV) of a geological formation, to determine a reflection coefficient (RC) associated with the geological formation, and to determine a density of the geological formation based on the CV and the RC. The CV and RC may be determined from values associated with sonic and ultrasonic velocity measurements. Additional apparatus, systems, and methods are described. ## Claims ### Claim 1 A system, comprising: a housing; sonic sensors attached to the housing; ultrasonic sensors attached to the housing; a processor; and a machine-accessible medium comprising program instructions executable by the processor to cause the system to determine a compressional velocity (CV) of a geological formation based on sonic signals measured by the sonic sensors, determine a reflection coefficient (RC) associated with the geological formation based on ultrasonic signals measured by the ultrasonic sensors, and determine the density of the geological formation based on the CV and the RC. ### Claim 2 (depends on 1) The system of claim 1, wherein the ultrasonic sensors comprise at least one of caliper sensors, pulse-echo sensors, or pitch-catch sensors. ### Claim 3 (depends on 1) The system of claim 1, further comprising at least one sonic transmitter attached to the housing, wherein the sonic sensors comprise a sonic receiver array. ### Claim 4 (depends on 3) The system of claim 3, wherein the sonic receiver array comprises one of multiple sonic arrays disposed around a periphery of the housing. ### Claim 5 (depends on 1) The system of claim 1, wherein the housing comprises one of a wireline tool, a logging while drilling tool, or a measurement while drilling tool. ### Claim 6 A method comprising: determining a compressional velocity (CV) of a geological formation based on sonic signals measured by one or more sonic sensors attached to a down hole tool; determining a reflection coefficient (RC) associated with the geological formation based on ultrasonic signals measured by one or more ultrasonic sensors attached to the down hole tool; and determining a density of the geological formation based on the CV and the RC. ### Claim 7 (depends on 6) The method of claim 6, wherein the CV is obtained using a time semblance estimate. ### Claim 8 (depends on 7) The method of claim 7, wherein the time semblance estimate is based on measurements from individual arrays or a sum of measurements from the individual arrays. ### Claim 9 (depends on 6) The method of claim 6, wherein the CV comprises an averaged formation compressional velocity. ### Claim 10 (depends on 6) The method of claim 6, further comprising: inverting the RC to reduce a variation between the RC and a theoretical reflection coefficient. ### Claim 11 (depends on 6) The method of claim 6, wherein determining the RC comprises: estimating the RC based on borehole reflected pulse amplitude and propagation path travel time. ### Claim 12 (depends on 11) The method of claim 11, wherein the RC is estimated using an impedance ratio function. ### Claim 13 (depends on 12) The method of claim 12, wherein the impedance ratio function has the form of A/B, wherein A comprises a difference of density and velocity products, and B comprises a sum of the density and velocity products, and wherein the density and velocity products comprise drilling fluid density and drilling fluid velocity, and density and velocity of the geological formation. ### Claim 14 (depends on 13) The method of claim 13, wherein the drilling fluid velocity is estimated from a known target distance or a direct surface measurement. ### Claim 15 (depends on 11) The method of claim 11, further comprising: correcting the borehole reflected pulse amplitude for attenuation along a propagation path of acquired signals associated with the RC. ### Claim 16 (depends on 15) The method of claim 15, wherein the correcting comprises: determining an actual distance traveled along the propagation path of acquired signals. ### Claim 17 (depends on 16) The method of claim 16, wherein determining the actual distance traveled comprises determining a signal travel time. ### Claim 18 (depends on 11) The method of claim 11, wherein the borehole reflected pulse amplitude is averaged over a number of acquisition cycles. ### Claim 19 (depends on 6) The method of claim 6, further comprises determining a fluid velocity based on ultrasonic signals measured by one or more ultrasonic sensors and determining a shear velocity based on sonic signals measured by one or more sonic sensors. ### Claim 20 A machine-accessible medium having instructions stored therein, wherein the instructions are executable to cause a machine to: determine a compressional velocity (CV) of a geological formation based on sonic signals measured by one or more sonic sensors attached to a down hole tool; determine a reflection coefficient (RC) associated with the geological formation based on ultrasonic signals measured by one or more ultrasonic sensors attached to the down hole tool; and determine a density of the geological formation based on the CV and the RC.