IMPLEMENTATION DSIW-System ELDFISK ALPHA MARS 2011

Transcription

1 IMPLEMENTATION DSIW-System ELDFISK ALPHA MARS 2011 Report: Wiping performance Pressure drop-rupture disc function-gas kick circulation Ketil Botnmark, Kjell Mikalsen This report resumes the operational performance of 2K Tools Drill String Internal Wiper-System at ConocoPhillips installation Eldfisk Alpha.

2 CONTENT The DSIW -System... 3 Executive summary... 5 Wiping performance... 6 DSIW pressure drop verification Rupture disc test... 8 Realistic gas kick incident... 8 DSIW exposure during circulation... 8 Performance summary... 9 Wiping action... 9 Pressure drop tests... 9 Rupture disc function... 9 Operational findings... 9 Conclusion... 9 Attachments Data gas circulation TEST DSIW-S ELDFISK ALPHA Side 2

3 The DSIW -System The Drill String Internal-System (DSIW-System) is designed for wiping the internal of drill string during tripping out of the borehole in operations off and onshore. Below the package delivered to ConocoPhillips; Typical DSIW Tool Rack located at drill floor that contains all required tools for internal wiping operations. (Storage position) 2K Tools Landing Sub with required dimensions. 2K Landing Sub designed to catch the DSIW tool. TEST DSIW-S ELDFISK ALPHA Side 3

4 Below in detail, DSIW-System components; Drill Floor Rack Permanently installed on driil floor Winch System Capacity to fish the DSIW appr. 248 mtrs. from RKB with wireline Transport tube For replacement and transport of tool to and from site Fishing tool Applied with the Winch system or the rig wireline unit Contingency DSIW Delivered with the system as back up tool DSIW Wiper tool 2K Tools Landing Sub Approx. 9 ft. Normally located on top of HWDP TEST DSIW-S ELDFISK ALPHA Side 4

5 Executive summary A Drill String Internal Wiper-System (DSIW-S) is rented by ConocoPhillips and was installed at Eldfisk Alpha 2. of Mars The DSIW-System contains a complete tool package to perform safe and efficient internal wiping of drill string when tripping out of the borehole. The DSIW-System has been applied during tripping operations since the installation of the system at Eldfisk Alpha. Satisfactory Wiping performance is verified trough several trips and is to ConocoPhillips satisfaction with practically no mud spills on the drill floor, drains, etc. Reliability of DSIW safety systems has been verified in the operations. Both water based (WBM) and Oil based (OBM) drilling fluids has been applied in the operations. An incident with a gas kick with the DSIW trapped inside the drill string was handled in a controlled way. The DSIW was during circulation pumped down to the 2K Landing Sub and landed in the seat. The circulation continued through the DSIW when seated the 2K Landing Sub and according to normal procedures and drilling practices. The system is easy to install and use by the rig crew. There is no need for service personal to install or operate the system. CONCLUSIONS The DSIW-System has proven it's capability and efficiency through field runs at the ConocoPhillips Eldfisk A. Numerous of wiper trips out of the hole has been performed through 5" drill pipe with satisfactory wiping efficiency. The DSIW has shown that it don't represent any restrictions in the string when it comes to free circulation. Any gain or kick situation during drilling operations can be performed as normal with the DSIW inside the string. The DSIW-System is easy to install, operate and handle by the rig crew. TEST DSIW-S ELDFISK ALPHA Side 5

6 Wiping performance The Wiping performance shown in the photos below gave minimum mud spills on drill floor and improved the working environment for the rig crew. The pictures below shows drill floor after wiping approx. 4,888 ft (1.489 mtrs.) of 5" DP. (Photo, ConocoPhillips) Prior to running the DSIW a few stands were pulled wet. This led to mud spills on the set back due to drain off from the drill pipe stands. (DSIW not applied) After pulling wet stands, a slug was pumped and DSIW was dropped into the string. The free fall of the DSIW inside the string was estimated to mtrs. before the DSIW got buoyant at the top of slug column. 2K Tools personal attend when pulling the first 3-5 stands and monitored satisfactory wiping function. The drill crew pulled the rest of the string problem free until the 2K Landing Sub reached the drill floor and the DSIW was picked out of the 2K Landing Sub. Photos above shows rotary table and set back after internal wiping of the total length of drill string mentioned above. To be observed in the photos, practically no mud spills on the drill floor, drains and DP threads. TEST DSIW-S ELDFISK ALPHA Side 6

7 DSIW pressure drop verification. One of the issues with a DSIW inside a drill string is if the tool represent any significant pressure drop if trapped inside the string. Therefore a controlled flow test was requested and performed. The following assembly was rigged up on the drill floor; 1) wash tool w/3 nozzles (to obtain SPP during tests) 2) 2K Landing Sub and 3)one stand 5" DP. It was pumped at 3 different flow rates to observe if there were any significant pressure drop caused by the DSIW tool located inside 2K Landing Sub. Similar test (flowrates) was performed without the DSIW located inside the 2K Landing Sub to compare the difference SPP. The table below confirms that the DSIW inside a drill string (2K Landing Sub) represent a minor difference pressure drop when circulating. Test results shown in table and diagram below: TEST SET UP STEP 1 STEP 2 STEP 3 With DSIW installed 93,5 psi (6,41 bar) 102 psi (7,03 bar) 130 psi (8,96 bar) Without DSIW installed 85 psi (5,85 bar) 88 psi (6,07 bar) 108,3 psi (7,45 bar) ΔP 8,5 psi (0,55 bar) 14 psi (0,97 bar) 21,7 psi (1,45 bar) FLOW RATE (SPM) FLOW RATE (l/min) FLOW RATE (GPM) MW: 1,5 sg. TEST DSIW-S ELDFISK ALPHA Side 7

8 Rupture disc test An important function of the DSIW is the rupture disc function. The function is to equalize the pressure inside the string and the buoyancy volume in the DSIW by filling up the buoyancy volume with mud. Equalizing the pressure eliminates the danger of collapsing the DSIW body when high SPP, and maintain the flow area and circulation function of the DSIW. After the "pressure drop verification" it was necessary to increase the standpipe pressure by increasing the flow rate to brake the rupture disc. The pumps where taken to 123 stroke/min (970 l/min) (256 GPM) that gave approx. 430 psi or 30 bar SPP. After achieving the rupture pressure, the DSIW was picked out from the 2K Landing sub and rupture of the disc was confirmed. (Photos below.) The DSIW rupture disc design pressure is approximate 290 psi (20 bar). The rupture function worked as it should by breaking the rupture disc and filling up the float volume of the DSIW. The DSIW body was in normal condition without any deformation due to the pipe pressure. Realistic gas kick incident During tripping out from the hole a positive gain was observed after the DSIW was dropped. Connecting and pumping had to be initiated with the DSIW inside the string. The DSIW was then gradually pumped down to the 2K Landing Sub. The gas kick was circulated out with the DSIW in the landing sub. The effective circulation time with the DSIW in the landing sub was 18 hrs. The operation confirmed very low pressure drop over the DSIW and it further confirmed that the DSIW can be circulated through without any negative operational consequences. The tool was recovered from the 2K Landing sub after the operation. DSIW exposure during circulation Hours circulated 18,75 hours Total flow volume GPM (1.684 m3) Average flowrate 395 GPM (1.497 l/min) Peak (max) flowrate 603 GPM (2.283 l/min) Duration peak flowrate 2,75 hours The figures shows the exposure to the DSIW tool during the kick circulation period. TEST DSIW-S ELDFISK ALPHA Side 8

9 Performance summary Wiping action The DSIW has wiped the 5" drill string and almost eliminated mud spills on drill floor, set back and DP threads. This is the conclusion through a number of wiper trips with the DSIW at Eldfisk A. Pressure drop tests The DSIW tool does not introduce any pressure drop of significance when it is landed in the landing sub during a kick situation. This is verified during controlled testing and also verified in the realistic gas kick incident described in this report. Circulation was performed as "normal" with DSIW inside the string. After stabilizing the well and finishing tripping out, the DSIW was recovered from the 2K Landing sub. Rupture disc function The rupture disc function is also verified as reliable. The rupture disc did break as predicted both during controlled tests and through the realistic kick incident down hole. The main function of the disc is to keep the tool body in a "as build" condition and to obtain the designed flow area for safe circulations. Operational findings After the 18 hours of circulation a wash out was observed in the DSIW fish neck. The neck is now replaced and installed at Eldfisk A with a new designed neck, to eliminate future wash outs. Other wear on the tool was of a minor (normal) character, and concluded as non critical. Conclusion The DSIW-System has successfully been implemented on Eldfisk Alpha as a part of the drilling equipment on the drill floor. The equipment has improved the working environment to the satisfaction of ConocoPhillips and the drilling contractor. Secondly the system has proven to be easy and safe to handle and operate by the rig crew. Ketil Botnmark Gen. Mngr. 2K TOOLS AS Kjell Mikalsen Technical Mngr. 2K TOOLS AS Dag Helge Breivik Director Drilling Eldfisk operations ConocoPhillips Norge AS Hans-Jacob Lund Eldfisk Drilling Superintendent ConocoPhillips Norge AS TEST DSIW-S ELDFISK ALPHA Side 9

10 Attachments Data gas circulation Date Duration Duration Flow Total flow FLOW Tot. Flow Tot flow hours minutes GPM Gallon l/min litres m , , , , , , , , , , , , , , , , , , , , , , , , , , , ,10 SUMS 18, Vital data kick situation, exposure DSIW tool Duration operation 18,75 hours 1125,00 mins. Total flow volume Gallon m3 Average flowrate 395,45 GPM l/min Peak flowrate 603 GPM l/min Duration peak (max) flowrate 2,75 hours TEST DSIW-S ELDFISK ALPHA Side 10

11 Drill String Internal Wiper -System TEST DSIW-S ELDFISK ALPHA Side 11

12 2K TOOLS AS Postboks NARVIK. N-Norway Visit address Teknologiveien Narvik N-Norway Phone Fax Ketil Botnmark Kjell Mikalsen Gen. mngr. Tech. mngr. Mob TEST DSIW-S ELDFISK ALPHA Side 12