# US 8,770,835 B2 · Apparatus and methods for estimating a characteristic of a fluid downhole using thermal properties of the fluid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,835 B2 - Document ID: US8770835B2 - Status: Granted - Kind: B2 - Application number: 11/867,138 - Filed: 2007-10-04 - Published: 2008-04-10 - Granted: 2014-07-08 - Earliest claimed: 2006-10-06 - Assignees: Baker Hughes Incorporated - Applicants: Stefan Sroka; Peter Schaefer - Inventors: Stefan Sroka; Peter Schaefer - Web page: https://patentgrep.com/patent/US8770835B2 ## CPC - E21B 49/10: using side-wall fluid samplers or testers - E21B 49/081: {with down-hole means for trapping a fluid sample (E21B49/10 takes precedence)} - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract The disclosure provides a system, tools and methods for estimating a property or characteristic of a fluid downhole. In one aspect, the method may include: heating the fluid at a selected or first location during a first time phase, taking temperature measurements of the fluid substantially at the selected location during a second time phase, and estimating the property of the downhole fluid using temperature measurements. Temperature measurements may also be taken at a location spaced apart from the first location and used to estimate the property of the fluid. The tool may include a device that heats the fluid during a first time phase and takes temperature measurements of the fluid during a second time phase. A processor uses the temperature measurements and a model to estimate a property of interest of the fluid. ## Claims ### Claim 1 A method for estimating a property of interest of a fluid, comprising: deploying a chamber into a wellbore; obtaining a fluid from a formation into the chamber; heating the fluid at a selected location in the chamber to a selected temperature during a heating phase using an element at the selected location; taking a plurality of temperature measurements of the fluid using the element at the selected location in the chamber during a sensing phase that follows the heating phase; taking a plurality of temperature measurements of the fluid at a location spaced apart from the selected location during the sensing phase; and estimating the property of the fluid from the plurality of temperature measurements taken during the sensing phase at the selected location and the spaced apart locations. ### Claim 2 (depends on 1) The method of claim 1, wherein the property of the fluid is one of: a phase change of the fluid; a proportion of a constituent of the fluid; a contamination level in the fluid; and a presence of one or more of oil, gas and water. ### Claim 3 (depends on 1) The method of claim 1, wherein estimating the property of the fluid from the plurality of temperature measurements further comprises: providing a model relating to the property of the fluid; and estimating the property of the fluid using the model and the plurality of temperature measurements taken at the selected location. ### Claim 4 (depends on 3) The method of claim 3, wherein the model is based at least in part on thermal properties of known fluids. ### Claim 5 (depends on 1) The method of claim 1, wherein the heating phase and sensing phase constitute substantially consecutive time periods. ### Claim 6 (depends on 1) The method of claim 1 further comprising extracting the fluid from the formation, pumping the fluid into the wellbore for a selected period of time, and then supplying the extracted fluid to the chamber. ### Claim 7 An apparatus for estimating a property of a fluid, comprising: a chamber configured to be deployed into a wellbore for holding a fluid extracted from a formation; and a device including an element that heats the fluid in the chamber to a selected temperature at a selected location during a heating phase and measures the temperature of the fluid substantially at the selected location during a sensing phase that follows the heating phase and at least one additional temperature sensor at a location spaced apart from the selected location configured to take a plurality of temperature measurements of the fluid during the sensing phase; and a controller that processes the temperatures measurements made at the selected location and the spaced apart location to estimate the property of the fluid. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the controller uses a model and the temperature measurements to estimate the property of the fluid. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein the device includes a heating element and a temperature sensing element. ### Claim 10 (depends on 7) The apparatus of claim 7 further comprising a sensor placed spaced apart from the device for measuring temperature of the fluid during a selected time period. ### Claim 11 (depends on 7) The apparatus of claim 7 further comprising a probe configured to abut the formation in a wellbore for conveying the fluid from the formation into the chamber. ### Claim 12 (depends on 11) The apparatus of claim 11 further comprising one of a pump and a low pressure chamber to cause the fluid to flow from the formation into the chamber, wherein the low pressure chamber has less pressure than the formation. ### Claim 13 (depends on 7) The apparatus of claim 7 further comprising a conveying member configured to convey the chamber and the device into a wellbore during one of: drilling of a wellbore and after drilling of the wellbore. ### Claim 14 (depends on 7) The apparatus of claim 7, wherein the property of the fluid is one of: a phase change relating to the fluid; a presence of one or more of oil, gas, water and contamination; a proportion of a constituent of the fluid; and a contamination level in the fluid. ### Claim 15 A wellbore system for estimating a property of interest of a fluid during extraction of the fluid from a formation surrounding a wellbore, comprising: a tool configured to be deployed into a wellbore that includes: a chamber for receiving the fluid extracted from the formation; a heat element that heats the fluid to a selected temperature during a heating period; a temperature sensor element that measures the temperature of the fluid during a sensing period that following the heating period, wherein the heat element and the temperature sensor element are a single element; at least one additional temperature sensor at a location spaced apart from the selected location that measurements the temperature of the fluid at the spaced apart location during the sensing period; a data storage device that stores a model relating to the property of the fluid; and a processor that utilizes the measurements made by the temperature sensor at the selected location and by the at least one additional temperature sensor at the spaced apart location and the model to estimate the property of interest of the fluid during the extraction of the fluid from the formation. ### Claim 16 (depends on 15) The system of claim 15 further comprising: a drilling assembly that carries the tool and a drill bit an end thereof for drilling the wellbore; and a conveying member that conveys the drilling assembly into the wellbore.