Initial integrity evaluation of storage and production wells

Transcription

1 Initial integrity evaluation of storage and production wells Thomas Brückner 1 of 23

2 Motivation Protection of human health & environment Legal requirements Technical specifications Economic reasons 2 of 23

3 Motivation Protection of human health & environment Legal requirements Laws and directives at various levels (international, national, federal) Technical specifications Economic reasons 3 of 23

4 Motivation Protection of human health & environment Legal requirements Engineering standards - technical guidelines (e.g. API, DIN) Recommended practices i.e. from industry associations (e.g. BVEG) Technical specifications Site-specific operational experience Economic reasons Recommendations from manufacturers 4 of 23

5 Motivation Protection of human health & environment Legal requirements Preventing loss or contamination of stored product Technical specifications Reduction of repair costs and down time Economic factors Maintaining durability of asset 5 of 23

6 Standards E DIN EN ISO and -2 NORSOK D-10 Oil & Gas UK Well Life Cycle Integrity Guidelines BVEG Technische Regel Bohrungsintegrität 6 of 23

7 Definition Barrier/Barrier system [DIN EN ISO ]: system of one or several well barrier elements (WBEs) that contains fluids within a well to prevent uncontrolled flow of fluids within or out of the well 7 of 23

8 The objectives of a well barrier [DIN EN ISO ]: withstand the maximum anticipated combined loads to which it can be subjected function as intended in the environments (pressures, temperature, fluids, mechanical stresses) that can be encountered throughout its entire life cycle prevent uncontrolled flow of wellbore liquids or gases to the external environment successfully undergo scheduled verification tests 8 of 23

9 Well Barrier Element (WBE): [DIN EN ISO ] One or several dependent components that are combined to form a well barrier [NORSOK D-10] A physical element which in itself does not prevent flow but in combination with other WBE s forms a well barrier. 9 of 23

10 Barrier systems & Barrier elements Wellhead / annuli / surface casing Completion SSSV / anchor seal / travel joint / packer system etc. Casing shoe LCC / casing & cementation Cavern Thermodynamics / rock mechanics and geology 10 of 23

11 Barrier systems & Barrier elements Primary barrier WBEs in direct contact to the medium Prevents flow from the reservoir in the borehole or from the borehole in other gelocical layers Plotting blue 11 of 23

12 Barrier systems & Barrier elements Primary barrier Typically primary barriers: cap rock (salt) casing cement production casing production packer completion string SSSV or tree master valve 12 of 23

13 Barrier systems & Barrier elements Secondary barrier Serves as a back-up in the event of the failure of the first barrier Envelops primary barrier Plotting red 13 of 23

14 Barrier systems & Barrier elements Secondary barrier Typically secondary well barrier is composed of the following WBEs: formation casing cement casing with hanger and seal assembly wellhead with valves tubing hanger with seals tree and tree connection 14 of 23

15 Common WBEs [BVEG]: Design or activity dependent necessity, to use one WBE as primary and secondary barrier Gemeinsame Barriereelemente Common Barrier Formation barrier Salt dome D Product Brine Barrieren Bohrungsstatus Eingeschlossen C Well Barrier Element Code Erstnachweis Monitoring (Beispiele) Primäre Barriere Thomas Brückner -Initial integrity evaluation of storage Ringraum and production D wells- 15 of 23 Salzstock 1 Drucktest N/A nach intialer Prüfung Ringraum C Produktionspacker 2 Drucktest Überwachung Ringraum C

16 Initial evaluation of well integrity Set up Information basis (basic documents) Geology Well/Cementation Completion Logs/Data sheets/as-built Operation history/incidents Etc. Evaluation of data situation Insufficient data situation: determination of measures for data acquisition 16 of 23

17 Initial evaluation of well integrity Elaboration Integrity strategy Set up Information basis Risk assessment (qualitative) acc. DIN EN ISO Identify of potential leak paths Evaluation of Risk Identify Load Cases 17 of 23

18 Initial evaluation of well integrity Evaluation of Well Integrity: Evaluation of operation history/incidents Evaluation of all WBEs acc. Acceptance criteria Matching of load cases acc. date situation Calculation of extreme load cases Measures Monitoring 18 of 23

19 Initial evaluation of well integrity Evaluation of well integrity: Example WBE Cementation Identification of potential leak pathes Identification of 1 st und 2 nd barrier Identification of WBEs Primary Barrier Secondary Barrier 19 of 23

20 Initial evaluation of well integrity Evaluation of well integrity: Example WBE Cementation Allocation of cement sections to 1 st and 2 nd barrier Evaluation of conducted tightness tests Evaluation of conducted logs Combined evaluation of all relevant logs 20 of 23

21 Initial evaluation of well integrity Evaluation of well integrity: Example WBE Cementation Risk evaluation Potential leak path Function Possible failure mode Potential consequences Probability of occurrence Amount of potential damage Risk Cementation Prod. Casing continuous, permanent, impermeable hydraulic sealing between casing and formation uncomplete filling, bad bonding, insufficient mech. strength Pressure in B- Annulus, Gas in B- Annulus. medium low medium Identification of potential load cases acc. risk matrix Simulation, calculation und evaluation of identified load cases with suitable software (WellCat) 21 of 23

22 Initial evaluation of well integrity Evaluation of well integrity: Example WBE Cementation Risk evaluation Load Cases Name Load type Casing Internal pressure profile External pressure profile Other 1 Burst 18 5/8" Cavern pressure Amb. pressure/hydrostatic - 1 Collaps 13 3/8" Hydrostatic Cavern pressure - 22 of 23

23 Initial integrity evaluation of storage and production wells Thank you for your attention 23 of 23