Well test Analysis Drill Stem Testing Type Curve.pptx

Oil and Gas Well Testing, Well Test Analysis. It explains the types of DST (open and cased hole) and the tools used, such as packers and pressure recorders. The sequence of operations is detailed, including setting the packer, opening the tester valve, and recording pressure data. The document also describes the typical trends observed in DST plots, highlighting key points like initial shut-in pressure and final flow pressure. Additionally, it provides recommendations for test durations under various conditions.

1. Topic: Well Test Analysis with Type Curve Course: Well and Gas Well Test Prof. Ashutosh Kumar Indian Institute of Technology (ISM) Dhanbad 2018

2. Drill Stem Test Drill Stem Test is temporary removal of static mud pressure applied to the formation to be tested to estimate its production potential. Cost effective and accelerated well testing. DST can be performed with open and cased hole conditions. Open hole DST is most economical way to determine reservoir productivity. Cased hole DST is used to re-evaluate old wells or new wells where poor formation conditions compels casing requirement. 2 Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

3. Drill Stem Test Both modes of DST with Inflate or Conventional type packers for formation isolation are used. Inflate type uses inflatable bladder to expand the packer elements. Two interval spaced packers are used to isolate the zone. Inflate type is most cost and time effective in multizone testing in single run of DST. Packer inflation is done by downhole inflate pump using annulus fluid. Conventional type packer uses compression set packer above the formation. 3 Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

4. Drill Stem Test: Objectives Identification of reservoir fluid Collect pressure transient data to estimate formation permeability, skin factor, and static reservoir pressure. Boundary condition of reservoir, Fluid recovery from the reservoir. 4 Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

5. Drill Stem Test: Parts of Tool 5 Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve   Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

6. Drill Stem Test: Sequence of Operation 6   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Mud DST Tool Running in DST Tool Running While running down the DST tool, Closed-in Pressure (CIP) valve and Bypass Port remain open and Tester Valve remain closed. As the DST tool is lowered down the hole, the hydrostatic pressure due to water/mud column increases. Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

7. 7   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Mud DST Tool Running in DST Tool Running At the desired depth packer is set, which isolates the formation from annular hydrostatic pressure (see the next slide). Tester Valve is opened and formation is exposed to to atmospheric pressure, formation fluid starts flowing into tool. Drill Stem Test: Sequence of Operation Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

8. 8   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Flowing Formation Flowing Formation Closed-in Pressure (CIP) valve and Tester Valve remain open and Bypass Port remains closed. Fluid entering DST tool may reach the surface. However, increase in the level of liquid causes increase in pressure. Drill Stem Test: Sequence of Operation Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

9. 9   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Formation Closed in Formation Closed in Once flow is established, Closed-in Pressure (CIP) valve and Bypass Port remain closed and Tester Valve remains open. Flow of fluids from formation slows down and pressure build up starts taking place. Drill Stem Test: Sequence of Operation Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

10. 10   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Equalizing Pressure Equalizing Pressure Once flow is established, Closed-in Pressure (CIP) and Tester Valves are closed. Sample of formation fluid is trapped. Bypass Ports are opened. Pressure equalizes across packer. It is helpful in releasing the packer from the borehole. Packer is unseated against the borehole and reverse circulation step is taken. Drill Stem Test: Sequence of Operation Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

11. 11   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Reverse Circulation Reverse Circulation Closed-in Pressure (CIP) valve is closed. Mud is pumped down the annulus which enter the DST tool at Reverse Circulating Sub; this displaces the fluids up the drill string for measurement at the surface. Drill Stem Test: Sequence of Operation Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

12. Drill Stem Test: Sequence of Operation 12   Blanked Oil Pressure Recorder Perforated Anchor Packer VR Safety Joint Bypass Ports Pressure Recorder Bypass Ports Tester Valve Dual Closed in Pressure Valve Dual CIP Circulating Port Reverse Circulating Sub Pulling Out of Hole Pulling Out of Hole Closed-in Pressure (CIP) valve is closed. Mud in the drill string bleeds into the annulus space through Reverse Circulating Valve. Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

13. Drill Stem Test: Conventional DST Plot 13            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

14. Drill Stem Test: Typical Trend of DST Plot 14 Part  - : Point  represents surface pressure. As the DST tool is lowered down the borehole, hydrostatic pressure due to mud column increases which is represented by  -  part of the pressure-time plot. At  tool has reached the desired depth and pressure recorded at  is corresponding hydrostatic pressure.            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

15. Drill Stem Test: Typical Trend of DST Plot 15 Part --: At  tool has reached the desired depth and pressure recorded at  is corresponding hydrostatic pressure. At  the packer is set. As a result of compression of mud below the packer, there is slight increase in the pressure represented by part  - .            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

16. Drill Stem Test: Typical Trend of DST Plot 16 Part -: As a result of compression of fluid due to packer setting, there is slight increase in the pressure represented by part  - . At point  the tester valve is opened and formation is relieved of hydrostatic pressure due to mud column which is represented by vertical decline of pressure from  to .            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

17. Drill Stem Test: Typical Trend of DST Plot 17 Part -: As the formation is relieved of hydrostatic pressure due to mud, formation starts flowing and fluid column starts rising and corresponding increase in pressure is recorded by part - of the plot. Point  is Initial Pre-Flow Pressure (IPFP) and point  is Final Pre-Flow Pressure (FPFP).            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

18. Drill Stem Test: Typical Trend of DST Plot 18 Part -: At the end of pre-flow period i.e. at point  the Test Valve is closed which results into pressure buildup as shown by part - of plot. This is Initial Shut-in Pressure (ISIP). The objective of initial shut-in period is to record the pressure of the reservoir before it starts any production. Initial shut-in period should be long enough for convenient extrapolation to maximum reservoir pressure.            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

19. Drill Stem Test: Typical Trend of DST Plot 19 Part -: At the end of initial shut-in period, Tester Valve is opened once again at point , that results in pressure drop as shown by part of curve -. This results in flow from the formation once again. This is second flowing period (Main Flow), which is aimed at collecting the fluid and analysing the data to estimate reservoir and fluid properties discussed earlier.            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

20. Drill Stem Test: Typical Trend of DST Plot 20 Part -: Point  is Initial Flowing Pressure (IFP) and at this point shows start of flow from formation. Rising fluid height results in increase in pressure as shown by the part - of the plot. The point  is Final Flow Pressure (FFP).            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

21. Drill Stem Test: Typical Trend of DST Plot 21 Part -: The point  is Final Flow Pressure (FFP). At this point, Test Valve is closed which results in pressure build up below the packer. Pressure rises to point  which is Final Shut in Pressure (FSIP).            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

22. Drill Stem Test: Typical Trend of DST Plot 22 Part - : Point  is Final Shut in Pressure (FSIP) at which Equalizing Valve is opened. The formation is exposed to hydrostatic pressure from mud column. Pressure across the packer (on top and bottom) are nearly same, that helps in easier unseating of packer.            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

23. Drill Stem Test: Typical Trend of DST Plot 23            Part - : At point packer is unseated, after which DST is pulled out of the borehole. With decreasing hydrostatic head due to mud column while pulling out, pressure recorded show a decreasing trend (part - of the plot). Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

24. Drill Stem Test: Important Points to Note 24 Duration of pre-flow or initial flow should be long enough to for the formation get released from hydrostatic mud pressure. Minimum recommended time is 3 to 5 min. Recommended time for initial shut in is 60 min. If total test time is short, it may be reduced to 45 min. However, minimum time for initial shut in 30 min. Time for final flow depends on blow observed during the test. If strong blow is observed, recommended time is 60 min; however, if reservoir fluid is produced at surface, longer time may be allowed to measure the flow rate. If blow dies, shut in should be done when it dies. Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

25. Drill Stem Test: Important Points to Note 25 Time for final shut in depends on the blow. If strong continuous blow is observed during the flow period, shut in time should be equal to that of flow time. However, minimum it should be 45 min. If blow dies, final shut in should be twice that of flow time. If reservoir fluid is produced at surface, shut in equal to half of flow time is recommended. Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.

26. Drill Stem Test: Recommendations 26 Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book. Test Period Test Condition Recommended Time Minimum Time Initial Flow All Short, purpose is release hydrostatic pressure 3 to 5 minutes Initial Shut in All 60 min. (If total test time is short then 45 min.) 30 minutes Times for Flow and Shut in in DST Test:

27. Drill Stem Test: Recommendations 27 Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book. Test Period Test Condition Recommended Time Minimum Time Final Flow Strong and continuing blow 60 minutes 60 minutes Blow dies Shut in after blow Reservoir fluid is being produced at surface 60 min or higher to gauge flow rate if time is available 60 minutes Times for Flow and Shut in in DST Test:

28. Drill Stem Test: Recommendations 28 Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book. Test Period Test Condition Recommended Time Minimum Time Final shut-in Strong and continuous blow during flow period Shut-in time = flow time 45 minutes Blow dies during flow Minimum shut-in= 2 X flow time Two times that of flow time Reservoir fluid being produced at surface during flow time Shut-in time = 0.5 X flow time 30 minutes Times for Flow and Shut in in DST Test:

29. Drill Stem Test: Typical Trend of DST Plot 29            Time Pressure Pre-Flow Initial Shut-in Main/Final Flow Final Shut-in Conventional DST Recorder Use of this material is restricted to B.Tech. VII Sem Students IIT(ISM) 2017. Supplement your reading with standard text book.        P ihm : Initial hydrostatic mud pressure P if1 : Initial flow pressure in 1 st flow P ff1 : Final flow pressure in 1 st flow P isi : Initial shut in pressure P if2 : Initial flow pressure in 2 nd flow P ff2 : Final flow pressure in 2 nd flow P fsi : Final shut in pressure P ihm : Final hydrostatic mud pressure