Marathon Drilling Indonesia Case History of Managed Pressure Drilling in Deepwater Marathon International Petroleum Indonesia Limited
Introduction Marathon signed a PSC for Pasangkayu block in Makassar Strait in September 2006 Potential prospects within the block included prognosed carbonate build-ups with potential for encountering karstified reservoirs which could result in massive losses while drilling In deep water a gas influx will not really start to expand until after it is above the Subsea BOP With the potential for massive losses, we were concerned that swapping of fluids (gas coming in with mud being lost) could mask an influx and result in gas getting into the riser without being detected Standard set up on most deepwater drilling rigs is not suited for handling a situation like this
Rig Sharing Consortium Six Companies with well commitments in the Makassar Strait area signed a Rig Sharing Agreement in October 2007 A rig tender was issued and evaluated with a Drilling Rig Contract for a DP Drillship being signed in February 2008 Several Consortium members had similar concerns regarding potential for encountering losses and have a gas influx get above the Subsea BOP undetected After signing the Drilling Rig Contract we immediately started discussions the Drilling Contractor to investigate methods to mitigate the risks of this unplanned event The Drilling Contractor was very proactive in providing ideas and g y p p g their engineering team provided details of equipment that was available from a project which had been cancelled
Riser Gas Handling On the Contracted rig the Choke, Kill, Boost and Hydraulic lines terminate on a dedicated termination joint below the slip joint This arrangement means that there are no lines attached to the slip joint therefore installing a shut off device below the slip joint is possible An 18-3/4 Annular BOP was available together th with an 18-3/4 flow spool with 2 x 6 outlets Had to commit quickly to have time to order forgings g for riser crossovers, long 6 high pressure hoses and extension hoses for the rig Choke, Kill, Boost and service lines Four of the Consortium members agreed a Contract Amendment with to add this to the Drilling Rig Contact The equipment was procured and shipped to Singapore where the rig was undergoing maintenance and planned SPS work at Sembawang shipyard
Riser Gas Handling Equipment Description Marine Riser - 21-in Stewart & Stevenson with SSQR-F connectors rated to 2,000,000, lbs tension. 3 15k C&K lines and 6 boost line Riser Circulating Spool with 2 x 6 outlets with double valves and hoses back to moonpool. A separate control panel was installed for the flow spool and annular 21-1/4 x 2K Hydril MSP subsea annular BOP above the flow spool Marine riser crossovers installed at the top and bottom of the RGH system to make up to the SSQR riser connections Control panel for the Annular BOP and Flowspool Valves complete with an umbilical and reel B ff if ld d fi d li i th l t ti i t th Buffer manifold and fixed lines in the moonpool area to tie in to the rig choke manifold and boost line
Riser Gas Handling additional equipment Following the decision to install the Riser Gas Handling system one of the Consortium members took the lead in exploring the possibility of adding a Rotating Control Device (RCD) into the set-up, together with flow control and pressure management systems (MPD Equipment) An MPD Contractor proposed their new below-tension-ring RCD which was designed to be deployed below the water line All parties worked together to develop detailed plans to install all the equipment necessary in the confined space available around the moonpool on the rig Marathon signed a contract to have the complete MPD system Marathon signed a contract to have the complete MPD system available for the first Marathon Well which was scheduled to start in the 2 nd quarter of 2010.
Riser Gas Handling Equipment Description The flowspool, annular, RCD, and crossovers were integrated into a 40ft joint, with standard riser connectors at each end which made allowed handling using the riser running tools, and the whole assembly could be installed through the rotary table The 40ft assembly was made up and loaded onboard the rig in Singapore in mid-april 2010 The buffer manifold and fixed lines were partially installed in the shipyard and had to be completed after the rig came on hire while drilling our riserless sections The MPD Manifold complete with Control system was also installed in the shipyard with final rig up and testing being completed at the first drilling location
Riser Gas Handling (RGH) & Riser Arrangement
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P&ID GSF Explorer 09CPDT004 MSEC Weatherford MPD equipment rig up RIG CHOKE MANIFOLD RC27 RC25 RC26 RC28 To MGS RC23 RC24 V4 STANDPIPE MANIFOLD P P P RC20 RC21 RC22 To Shakers SP9 SP10 SP11 SP5 SP6 SP7 SP8 SP4 SP1 SP2 SP3 RISER BOOST MANIFOLD P P To Shakers RC15 RC16 RC17 RC18 RC11 RC12 RC13 RC14 RC9 RC10 RC5 RC6 RC7 RC8 RC1 RC2 RC3 RC4 From CMT Unit RC19 Boost line Kill Line Choke Line P To Shakers KL1 BUFFER MANIFOLD BM1 BM2 BM3 BM4 BM5 BM6 BM7 V1 P SC1 CORIOLIS Choke A GV4 GV7 GV3 GV1 GV6 GV2 GV8 GV5 Choke B SC2 SECURE MANIFOLD V2 V3 se Separator Two Phas Gas to Vent RB1 RB2 RB3 RB6 MP8 MP7 MP6 RB5 Boost line RB7 Kill Line RCD oke Line Cho MP5 MP4 Annular BOP MP3 MP2 MP1 RB4 Boost line Riser B Mud Pump 3 Mud Pump 2 Mud Pump 1 Riser boost pump PV4 PV3 Flow spool PV2 PV1
MPD System actual performance After installing the surface rig up described we also replaced a set of pipe rams on the SSBOP with a second set of Blind Shear Rams This allowed us to use the entire riser as a long lubricator for running BHA s s, Liners, Wireline Logging Strings while holding pressure below a set of Blind Shear Rams (did not want to be using the main BSR for this purpose and possibly compromising their integrity) The system was used very successfully to log under pressure, run liners and to drill using Pressurised Mud Cap Drilling on both the Bravo and Romeo Wells Prior to drilling out from the 16 and from the 13-5/8 we installed the RCD bearing assembly and allowed all crews to familiarise themselves with the system, circulate through it and become comfortable with how it was set up