To condition a wellbore with a reamer on a wireline, a portion of a wellbore is formed from a surface of the earth toward a subsurface hydrocarbon reservoir using a wellbore drilling assembly. After forming the portion of the wellbore, the wellbore drilling assembly is removed from the portion of the wellbore. Using a wireline, a wellbore sampling tool and a reamer are lowered into the portion of the wellbore. While maintaining the wellbore sampling tool and the wireline in a non-rotational state, the portion of the wellbore is cleaned using the reamer.

Methods and apparatus for estimating a presence of oil-based mud (OBM) in a downhole fluid. Methods include generating measurement values by measuring one or more gross physical properties of the downhole fluid with at least one sensor, the measurement values comprising at least one measurement value representative of each gross physical property; and estimating with at least one processor a relative concentration of OBM with respect to the downhole fluid by using a model correlating the measurement values with the relative concentration. Methods may include taking measurements from the downhole fluid in situ and/or estimating the relative concentration in real-time with respect to generating the measurement values. The model may comprise a correlation prediction function mapping the measurement values to the relative concentration, which may use the measurement values as input to predict the relative concentration.

Formation fluid sampled from within a wellbore is separated into gas and liquid fractions while downhole and in a wellbore. A separator vessel is used to isolate the gas and liquid fractions from one another. Baffles are arranged in a staggered formation within the separator vessel and in the path of the flow of the sampled formation fluid. Contact with the baffles perturbs the flow of sampled formation fluid, which promotes escape of the gas fraction from the fluid. The gas fraction is ported from an upper end of the sample vessel to a sample bottle for analysis. The liquid fraction collects in a lower end of the sample vessel, and is discharged into the wellbore.

A method includes conveying a wireline toolstring into a wellbore to perform a downhole operation, wherein the wireline toolstring has a single packer disposed thereon. The method also includes positioning the wireline toolstring in the wellbore adjacent a zone of interest, wherein the zone of interest has a barrier is located at one end of the zone of interest and the wireline toolstring is positioned such that the single packer is located adjacent the zone of interest such that the zone of interest is between the single packer and the barrier. The method can also include setting the single packer and performing a wellbore operation.

A method including, without removing a BHA from a wellbore of a well extending into a formation, extending, into an interior flow bore of the BHA, a first component of a wet latch assembly to provide an extended first component of the wet latch assembly, conveying downhole via a wireline cable, from a surface through an interior flow bore provided by a drill string, a second component of the wet latch assembly, and coupling the second component of the wet latch assembly with the extended first component of the wet latch assembly such that an electrical connection is established between the first component and the second component and between the BHA and the surface via the wireline cable, and testing the formation with a formation tester of the BHA, while providing power and/or data telemetry for the formation tester via the wet latch assembly and the wireline cable.

A siphon pump chimney can be used in a mini-drillstem test to increase formation fluid flow rates. A formation tester can be coupled to a siphon pump chimney via a wet connect assembly to transfer formation fluid from a fluid-bearing formation. The siphon pump chimney can receive the formation fluid through the wet connect and disperse the formation fluid into a drill pipe that is flowing drilling fluid. The siphon pump chimney can include check valves to prevent the drilling fluid from entering the siphon pump chimney. The siphon pump chimney can be configured to have a variable height that can reduce pressure within the siphon pump chimney to a pressure value that can be close to or less than the formation pressure, which can allow a pump to operate at high flow rates or be bypassed in a free flow configuration.

A method including, without removing a BHA from a wellbore of a well extending into a formation, extending, into an interior flow bore of the BHA, a first component of a wet latch assembly to provide an extended first component of the wet latch assembly, conveying downhole via a wireline cable, from a surface through an interior flow bore provided by a drill string, a second component of the wet latch assembly, and coupling the second component of the wet latch assembly with the extended first component of the wet latch assembly such that an electrical connection is established between the first component and the second component and between the BHA and the surface via the wireline cable, and testing the formation with a formation tester of the BHA, while providing power and/or data telemetry for the formation tester via the wet latch assembly and the wireline cable.

A downhole tool comprises at least one inlet and a first pump coupled to the at least one inlet via a first flow line. The first pump is to pump at a first pump rate to extract fluid via the at least one inlet from a subsurface formation in which a borehole is created and in which the downhole tool is to be positioned. A sample chamber is coupled to the inlet via a second flow line, and a second pump is coupled to the inlet via the second flow line. The second pump is to pump at a second pump rate to extract the fluid via the at least one inlet from the subsurface formation and for storage in the sample chamber. The first pump rate is greater than the second pump rate.

To condition a wellbore with a reamer on a wireline, a portion of a wellbore is formed from a surface of the earth toward a subsurface hydrocarbon reservoir using a wellbore drilling assembly. After forming the portion of the wellbore, the wellbore drilling assembly is removed from the portion of the wellbore. Using a wireline, a wellbore sampling tool and a reamer are lowered into the portion of the wellbore. While maintaining the wellbore sampling tool and the wireline in a non-rotational state, the portion of the wellbore is cleaned using the reamer

Embodiments provide a method for evaluating a hydrocarbon-bearing formation. The method includes the step of identifying a hydrocarbon sweet spot. The identifying step includes determining a carbon dioxide content of a gas sample retrieved from the hydrocarbon-bearing formation. The identifying step includes determining an isotopic signature of carbon dioxide of the gas sample. The carbon dioxide content of the gas sample retrieved from the hydrocarbon sweet spot can have a mole percentage ranging from 9 percent to 20 percent. The isotopic signature of carbon dioxide of the gas sample retrieved from the hydrocarbon sweet spot can have a δ.sup.13C value greater than −10 per mil. The identifying step can further include determining a cutoff range of the carbon dioxide content corresponding to the hydrocarbon sweet spot. The cutoff range can have a mole percentage ranging from 9 percent to 20 percent. The identifying step can further include obtaining a gas flow rate of the hydrocarbon-bearing formation. The gas flow rate can be greater than 10 million standard cubic feet per day.