Crude oil and condensate sampling. Jiskoot Ltd

Transcription

1 Crude oil and condensate sampling Jiskoot Ltd

2 Jiskoot UK and USA based International network of over 50 agents Our equipment handles over 60% of world crude oil Local support Sphere of operations Sampling Custody transfer, allocation and quality Blending Crude oil, bunker fuel Multiphase Metering

3 Why sample? Determine the quality Reduce losses Measure water Measure quality Measure density Value the batch Allocation/taxation measurement Comply with legislation and reduce the risk of dispute

4 How should you sample? Hierarchy of sampling In ships tanks In shore tanks By manifold samplers By a quality in-line sampling system Volume analysed is 1 in 300,000,000,000

5 Hydrocarbon sampling standards Automatic pipeline sampling ISO 3171 API 8.2 IP 6.2 Compliance with ISO will mean compliance with all others

6 Basic requirements Homogeneity of pipeline contents Extraction of a flow proportional and representative sample Correct sample handling and mixing Laboratory analysis Proving the system by water injection

7 Pipeline homogeneity (mixing) Where do you take the sample? Pipeline must be well mixed to extract a representative sample High Density Liquid (Water) Low Density Liquid (Oil)

8 Which sample would you want? Samples taken using a multipoint profile probe Which sample would you want, top or bottom? Crude Oil Water

9 Mixing - ISO 3171 Annexe A & C

10 Mixing - Quote from annexe C When a potential sampling location has been selected it is recommended that the calculation procedures in annexe A should be then used to estimate the adequacy of water dispersion, and thus confirm or disprove the choice of location. Mixing is dependant on viscosity and density as well as velocity!! ISO 3171 annexe A should ALWAYS be used to check mixing

11 Mixing ISO Annexe A Calculation of C1/C2 ratio (Water concentration at top of pipeline as a ratio of water concentration at the bottom. It must be greater than 0.9 for the whole flow range ) 1 10 C1/C2 Profile Ratio As flowrate falls droplets get bigger and there is poorer mixing (stratification) Straight Pipe Droplet Size Droplet Sze (mm) Flow (Thousand M3/Hr) For adequate Sampling C1/C2 >0.9 0

12 Dispersion and distribution Pipeline Mixing Quality - 858kg/m3-31.6Cst 0.90 C1/C2 Ratio STRAIGHT PIPE Flowrate (m3/hr)

13 Dispersion and distribution Pipeline Mixing Quality - 858kg/m3-6.9Cst 0.90 C1/C2 Ratio STRAIGHT PIPE Flowrate (m3/hr)

14 Dispersion and distribution Pipeline Mixing Quality - 720kg/m3-6Cst 0.90 C1/C2 Ratio STRAIGHT PIPE Flowrate (m3/hr)

15 Dispersion and distribution Pipeline Mixing Quality - 720kg/m3-2Cst 0.90 C1/C2 Ratio STRAIGHT PIPE Flowrate (m3/hr)

16 The correct way to assess mixing Standards provide a simple guide (ISO 3171 annexe C - API table 2) ONLY valid at one density and viscosity and this is stated in the standards Annexe A calculations recommended for every application C1/C2 must > 0.9 for ALL flow conditions C1/C2 ratio calculated at the worst conditions Minimum viscosity, density and flow rate Mixer must always be sized for worse condition

17 Representative sampling Samples must be taken flow proportionally Sample taken from the central 1/3rd of pipeline Each 1ml sample grab must be repeatable (normally ±2%) Irrespective of changes in viscosity, pressure or density Sampler must take high enough frequency samples to take 1-15 litres of sample Depending on application Sampler performance monitoring

18 Performance monitoring Continuous measurement of system performance Receiver weighing system that measure accumulated mass and uses volume and density Controller provides performance factor calculation Alarms in the event of errors during custody transfer to allow recourse to backup manual sample Documentation validating performance factor > 0.9

19 Sample handling & mixing Minimum number of steps from sampler to laboratory Portable receivers recommended (especially high RVP) Easy to handle and difficult to handle incorrectly Easy to clean Crude vapour pressure Constant pressure receivers Low pressure receivers Must have a facility for mixing prior to extraction of sub-sample

20 Laboratory analysis Receiver contents mixed Avoid too much heating Sub-sample must remain representative Analysis Methods Water - Karl Fisher preferred method Sample storage/retention

21 System proving System proving by water injection Standards define a procedure Proves the whole installed system to be valid Can be independently witnessed and certified to validate the system to buyer and seller In many markets proving is used to validate the system performance for customs taxation revenue allocation purposes

22 Basic requirements Homogeneity of pipeline contents Extraction of a flow proportional and representative sample Correct sample handling and mixing Laboratory analysis Proving the overall system Do ALL the steps right or not bother!

23 Which type of sampling system? Probe based In-Line system Fast loop bypass system Combined mixing and sampling (CoJetix) system If all the 5 steps are followed the system accuracy/uncertainty is determined by mixing/extractor size

24 In-line sampling system Typical uncertainty %

25 Fast loop sampling system Typical uncertainty %

26 Combined mixing/sampling system Typical uncertainty < %

27 Accuracy/uncertainty difference Relationship of the takeoff size to mixing Droplet Size/Takeoff Size = 0.1 CoJetix Fast Loop Water droplet In-Line Which is Potentially More Accurate?

28 Proving test results over 120 Water recovery from water injection testing of automatic sampling systems 0.20% 0.00% Absolute error in water recovery (-ve number indicates undermeasurement of water) -0.20% -0.40% -0.60% -0.80% -1.00% -1.20% CoJetix Sampling System In-Line sampling system with poor mixing in-line & JetM ix sampling system -1.40% Number of water injection tests

29 PROVEN relative performance Combined (CoJetix) sampling system Uncertainty % Improved WIOM and density uncertainty Fast loop sampling system Uncertainty % Suitable for applications with sufficient mixing i.e. C1/C2 > 0.9 Improved WIOM and density uncertainty In-line sampling system uncertainty %

30 CoJetix sampling and analysis system

31 Fiscal duty sampling and density

32 To minimise uncertainty Mix the pipeline to ISO 3171 At worst conditions (min viscosity, density & flow) Use a large take-off and a bypass loop Design the loop correctly Install densitometers and OWD water cut monitors if you need them. Minimise sample handling by using portable receivers Use coulometric titration Water injection prove the systems

33 System components

34 JetMix

35 JetMix Energy input increases as flowrate decreases Installed without depressurising/draining Mixing energy added to flow rather than derived from it No pressure drop Removable for pigging Recycle loop Simple to maintain

36 Sample probes 210 range of probes Suitable for high viscosity arduous duty (8000 cst) Air and hydraulic actuation 3 step positive displacement action 0-200bar Fixed or withdrawable Can be installed by hot tap and withdrawable for pigging

37 Sample probes 710 range of probes Suitable for medium viscosity and duty Fixed or withdrawable 0-50bar 3phase electric and air actuation 3 step positive displacement action Can be installed by hot tap and withdrawable for pigging

38 Sample probes 007 probe Suitable for light crude and refined product (<150 cst) Suitable for small pipelines 1¼ NPT or 2 ANSI fitting 0-19bar 3 phase electric actuation 3 step positive displacement action

39 Cell samplers 210 range for bypass systems (quality loops) Suitable for high viscosity arduous duty (8000 cst) Full bore sampler 1 or 2 available 0-200bar Air and hydraulic actuation 3 step PD action Minimal retained volume Max 100 grabs a minute

40 Cell samplers 710 range for bypass systems (quality loops) Suitable for medium viscosity and duty Full bore sampler 1 or 2 available 0-50bar - ANSI phase electric actuation 3 step PD action Minimal retained volume Max 50 grabs a minute

41 System components ByScoop large bore bypass loop extractor Suitable for sampling and quality loops Mounts in central third of pipeline (ISO,API & IP) Inlet and return in single tapping Large 33.5mm inlet Fixed or withdrawable Can be installed by hot tap and withdrawable for pigging

42 System components Low pressure portable sample receivers Available with 9, 18 and 35 litre capacity Built in mixing pipework and keyed connections for sub-sample mixing High level sensor available Pressure relief valve, gauge and removable lid Simple to clean and re-use

43 System components Constant pressure sample receivers Suitable for gas and liquid Maintain samples at line pressure for analysis Portable and compact No external rods (expansion space not required)

44 System components CanWeigh Continuous measurement of mass of accumulated sample Used by controller for performance factor calculations (ISO & IP) Can initiate receiver auto-change Provide receiver in place signal for alarm

45 System components InSpec sampler controller Complies FULLY with ISO 3171, API 8.2 & IP 6.2 Easy to read scrolling display with configurable bar-graphs Front panel can be remotely mounted PC based configuration backup and restore feature Operator and engineer security passwords Flow or time proportional sampling Integrated remote auxiliary control Configurable for use with any vendors samplers or receivers

46 System components LabMix Used to mix sample in receiver prior to removal of sub-sample for analysis Septum or tap for sample removal Connectors are keyed to ensure correct use 110/220 or pneumatic versions available

47 System components Hydraulic extractors Designed for the safe insertion and removal of probes, Inturbine and JetMix under line pressure for line pigging or maintenance

48 System components Inturbine flow meter Designed specifically for high turndown crude oil unloading applications Suitable for 8 52 pipelines m/s +/- 5% Can be installed by hot tap and withdrawable for pigging

49 Accessories Receiver full and 80% full sensors Line balanced relief valves Increases seal life in high pressure/arduous duty) Grab sensor Checks the actuation of each sample grab Probe weatherproof housing Can include heating IP55 IP66 available Receiver cabinet heating systems Fully fitted receiver cabinets Whole range of other sampling products

50 Thank you Any questions