Subsea Sampling Performed in the Deepwater BC-10 Field Offshore Brazil

摘要

The BC-10 O-North field is developed using water injection for pressure support. For reservoir managementrnit is of substantial value to know the source of water observed in each well. Due to comingled wellsrnand long flow lines, individual well sampling topsides is very difficult and give undesirable productionrndeferment. To enable well fluid sampling from each individual producer, a subsea sampling access hasrnbeen installed in Xmas tree. ROV deployed subsea multiphase sampling tools (SuMS Tools) have beenrndeveloped, and a first subsea sampling campaign has been executed, retrieving samples from twornindividual wells in the BC-10 O-North field. The paper discuss the motivation for the sampling program,rndescribe the sampling system, including Xmas tree modifications, sampling tool development andrnqualification, and describe the offshore execution of the first sampling campaign, with operationalrnexperiences and lessons learned. In addition to the technical content, this paper will also discuss thernorganizational and HSSE aspects of the sampling system and sampling process.rnThe technology used consists of a SuMS panel installed on the subsea Xmas tree, which enable accessrnto the production flow when connecting the ROV manipulated SuMS tool. The well is kept producingrnduring the tool connection, sampling period and tool disconnection, enabling a sample to be taken withrnstable flow conditions. After retrieval to the intervention vessel, the ROV tool with the sample isrntransported to shore, where the sample bottle is disconnected, and brought to a laboratory. In the lab, thernfluids are separated into gas oil and water before being shipped to the analyses laboratory in the US.rnThe first sampling campaign was successful. The operation was performed efficiently, without anyrnenvironmental or production impact, or damage to subsea hardware.rnThe SuMS technology is innovative, and is a significant step forward in reservoir management ofrnsubsea wells in cases where individual well sampling at the topsides facility is not feasible or desirable.rnIt is also presented as an alternative to the use of test separators for MPFM calibration, preventingrnproduction deferment.