Intrinsically Safe Acoustic Instrument Used in Troubleshooting Gas Lift Wells

Transcription

1 Gas Well Deliquification Workshop Sheraton Hotel, Denver, Colorado February 17 20, 2013 Intrinsically Safe Acoustic Instrument Used in Troubleshooting Gas Lift Wells Lynn Rowlan, Echometer Company Carrie-Anne Taylor, Echometer Company

2 Offshore Platform Santa Barbara California Technician s Van & Wellhouse: Alaska s North Slope Stringent safety requirements, by major operators when fluid level measurements are performed offshore or in enclosed wellhead spaces such as in Alaska s North Slope, create procedural complications. Feb , Gas Well Deliquification Workshop Denver, Colorado 2

3 Intrinsically Safe Acoustic Instruments 1. Some operators require Safe instruments in certain locations, most offshore platforms and certain fields. 2. Some Countries and States require Safe instruments in all oil and gas related operations. 3. Gas Lift is common artificial lift method for high rate wells Feb , Gas Well Deliquification Workshop Denver, Colorado 3

4 Fluid Level on Gas Lifted Horizontal Well 128 BL/D 140 Mscf/D Liner Top Liquid Level at Measured Depth of Feet Above Packer (10081 ) and Bottom Valve (10041 ) Feb , Gas Well Deliquification Workshop Denver, Colorado 4

5 Echoes from Gas Lift Mandrels Do Not Lineup Press = 513 psig Temp = 70Deg F Press = 688 psig Temp = 180Deg F E Average Acoustic Velocity 1134 ft/sec from Echo off 4.5 Liner Top Liner Top Used for Distance to LL Feb , Gas Well Deliquification Workshop Denver, Colorado 5

6 Acoustic Velocity Increases from 1072 Surface to 1238 ft/sec at the ft Liquid Level Surface Press = 688 psia Temp = 180Deg F Press = 513 psia Temp = 70Deg F Feb , Gas Well Deliquification Workshop Denver, Colorado 6

7 Anomaly Marker Analysis Method Purpose Accurately calculate the distance to the liquid level plus other downhole reflectors such as gas lift valves, tubing collars, subsurface safety valves and possible holes or other problems. Distances Determined using echoes from gas-lift valves at known distances from the wellhead. Accounts for Variations of acoustic velocity commonly observed in most wellbores due to variations of temperature, pressure and gas composition as a function of depth. Feb , Gas Well Deliquification Workshop Denver, Colorado 7

8 Anomalies are Markers in the Well at Known Distances Anomaly distances are entered as Well Marker Info Initially based on an estimated acoustic velocity, tick marks along the depth axis are located at distances that would correspond to the location of the anomaly echoes. Anomalies don t match echoes, relocates each tick mark to match exactly the beginning of the echo for a specific anomaly. Anomaly echoes are fixed to known depths by starting from the first anomaly, then from the first anomaly to the second anomaly and so on until the distance to the liquid level is accurately determined. Feb , Gas Well Deliquification Workshop Denver, Colorado 8

9 Anomaly Analysis Example Noisy Initial Acoustic Trace With Anomaly Echoes Collars Anomaly Echo Feb. 6-10, Gas-Lift Workshop 4 9

10 See Echoes Better by Removing Noise From Acoustic Trace Scale up trace to see better. 10

11 Identify/Select Correct Liquid Level Echo Move the LL marker to the knee of the kick. 11

12 Liquid Level Depth is Approximate 12

13 Known Depth of Anomalies 13

14 Make Depth Accurate by Identifying Each Anomaly SSSV 14

15 Next Anomaly Automatically Selected At first glance, it appears the automatic pick of marker is a little to the left of the kick. 15

16 Fine Tune Location of Selected Anomaly But we also see a kick to the left of the marker. Some quick calculations tell us that this is not a repeat. Select Interval Left to get a clear picture of the reflection located just below the 6 second mark. 16

17 Examine the Acoustic Trace and Select Correct Echo This is a much more likely position for the placement of the next marker. 17

18 Continue Down Trace Selecting Anomaly Echoes If the correct marker is not selected, then move window to see the marker echo. 18

19 Continue Down Trace Selecting Anomaly Echoes 19

20 Continue Down Trace Selecting Anomaly Echoes Scale UP if needed to verify that this is the last marker before the liquid level. 20

21 Anomaly Echoes Below the Liquid Level are Negligible Gas Lift Mandrel 8 and the Packer are below the liquid level marker so these last two markers can be skipped. 21

22 Accurate Distance to Liquid Level Using Anomaly Depths 22

23 Discussion of Anomaly Analysis New Technology Does the Calculations on the Acoustic Trace for You Identifying Anomaly Echoes is Simplified Marker Depths are Automatically Determined Manual Adjustments Required For Accuracy Data is digital and not on a Strip of Paper, so Safe Backup of Information is Done Recall of Data and Re-analysis is a Straight Forward Process Feb , Gas Well Deliquification Workshop Denver, Colorado 23

24 Intrinsically Safe Equipment Intrinsically safe equipment and wiring shall not be capable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific atmospheric mixture in its most easily ignited concentration. Feb , Gas Well Deliquification Workshop Denver, Colorado 24

25 Classification of Hazardous Zones Rod Pumped Well: API-RP500 Division 1 Zone In the sump; Hydrocarbon gases heavier than air may accumulate. Division 2 Zone Surrounding the tree, stuffing box, and a portion of the flowline. Feb ,

26 Feb , Gas Well Deliquification Workshop 26 Denver, Colorado Explosion Prevention Methods Explosion-Proof Enclosures Purging or Pressurization Encapsulation Oil Immersion or Powder Filling Intrinsic Safety

27 Feb , Gas Well Deliquification Workshop 27 Denver, Colorado Requirements for Intrinsic Safety Simple Apparatus Thermocouples, RTD s, switches, LED s Strain Gage type pressure transducer, dynamometer load cell transducers Intrinsically Safe Certified Apparatus Transmitters, current to pressure converters, solenoid valves, piezoelectric microphones Intrinsic Safety Barrier

28 Feb , Gas Well Deliquification Workshop 28 Denver, Colorado Intrinsically Safe Field Devices Gas Gun Acoustic Instruments Microphones used in the wellhead attachments include piezoelectric crystals. Special intrinsic safety barrier microphones are manufactured. Solenoid device on the remotely fire gas guns must be Encapsulated and power line must be Pressurized for intrinsic certification. So often the acoustic instrument will be manually operated and fired.

29 Intrinsically Safe 5000 psi Gas Gun Often used to Shoot Gas Lift Wells 5000 psi rated Gas Gun is modified, as shown by the engravings, with a special microphone for use in hazardous areas. Feb , Gas Well Deliquification Workshop 29 Denver, Colorado

30 Feb , Gas Well Deliquification Workshop 30 Denver, Colorado Intrinsically Safe Fluid Level Instruments Computerized Recorder or Strip Chart Recorder Modified with safety circuits to limit electrical energy output in the event of a component malfunction. Must be installed in a safe area when used with the certified gas guns that are located in a hazardous area.

31 Installation Drawing for Instrument with Intrinsic Safety Barrier Intrinsic Safety Barrier

32 Intrinsically Safe Fluid Level Instrument Located in Hazardous Area When installed correctly and used in conjunction with a certified field device is approved for use inside hazardous environments. 32

33 Conclusion Intrinsically Safe Field Instruments 1500psi Compact Gas Gun 5000psi Gas Gun, also design/construction materials meet MR to allow use in corrosive CO2 and H2S environments Intrinsically Safe Fluid Level Instruments Model M Chart Recorder (Install and operate within Safe Zone) Model H Digital Recorder (Can be operated within Hazardous Zone) Intrinsically Safe Computerized Well Analyzer Model E (Install and operate within Safe Zone) Pressure Transducer, Strain Gage Dynamometer transducers considered Simple Apparatus Feb , Gas Well Deliquification Workshop Denver, Colorado 33

34 Copyright Rights to this presentation are owned by the company(ies) and/or author(s) listed on the title page. By submitting this presentation to the Gas Well Deliquification Workshop, they grant to the Workshop, the Artificial Lift Research and Development Council (ALRDC), and the Southwestern Petroleum Short Course (SWPSC), rights to: Display the presentation at the Workshop. Place it on the web site, with access to the site to be as directed by the Workshop Steering Committee. Place it on a CD for distribution and/or sale as directed by the Workshop Steering Committee. Other use of this presentation is prohibited without the expressed written permission of the author(s). The owner company(ies) and/or author(s) may publish this material in other journals or magazines if they refer to the Gas Well Deliquification Workshop where it was first presented. Feb , Gas Well Deliquification Workshop Denver, Colorado 34

35 Disclaimer The following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Gas Well Deliquification Web Site. The Artificial Lift Research and Development Council and its officers and trustees, and the Gas Well Deliquification Workshop Steering Committee members, and their supporting organizations and companies (here-in-after referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Gas Well Deliquification Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained. The views, opinions, and conclusions expressed in these presentations and/or training materials are those of the author and not necessarily those of the Sponsoring Organizations. The author is solely responsible for the content of the materials. The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. The Sponsoring Organizations provide these presentations and/or training materials as a service. The Sponsoring Organizations make no representations or warranties, express or implied, with respect to the presentations and/or training materials, or any part thereof, including any warrantees of title, non-infringement of copyright or patent rights of others, merchantability, or fitness or suitability for any purpose. Feb , Gas Well Deliquification Workshop Denver, Colorado 35