Delivering wells capable of high rate and high ultimate recovery heavy oil is one of the key requirements for success of the Ultra-deepwater Parque das Conchas development in block BC-10, Campos Basin, Brazil.
This paper presents the Parque das Conchas well design to achieve these objectives while tackling key challenges such as shallow reservoir setting below mud line and low fracture gradient setting. It explains fabrication and final preparation efforts followed by a detailed description of execution efforts on the Transocean mobile drilling unit Arctic-1, including performance and learnings by well section.
The Parque das Conchas well design and execution efforts have resulted in several significant results to date:Two of the longest horizontal open hole wells successfully drilled and completed with a full-length alpha and alpha/beta wave gravel pack in Brazil at 1,115 and 1,160m.Top quartile drilling and completion times.Use of the Transocean Arctic-1 with a surface BOP (SBOP) system (Ref 1).Promising well performance from initial production.
For the drilling and completion of the Parque das Conchas wells a combination of existing and new technologies have been used. New technologies include the SBOP system, Spacer Spool, Collapsible 9-5/8" Casing Shoe Joint, 4-1/4" washpipe, tailpipe swell element and premium sand control screens with extensive mesh size QA/QC. Existing technologies are point the bit rotary steerable, Production Screen Tested (PST) drilling fluid, Alpha Wave Gravel Packing, Delayed Filtercake Breakdown system and Fluid Loss Valve (FLV) lower completion isolation.
Well construction results have been excellent to date with the wells delivered on time, within budget and with productivity indices exceeding expectations. Credit goes to a team of people working closely together across disciplines in wells, subsurface, subsea, production operations, HSE, logistics, finance and QA/QC departments, across a global team.
Introduction
The BC-10 block is located in the Campos Basin approximately 120 km southeast from the city of Vitoria off the coast of Brasil. Water depths in this ultra deepwater block range from 1,400 to 2,000 m. Shell is the operator with a 50% interest in a joint venture with Petrobras and ONGC with 35% and 15% interest, respectively. A total of 14 exploration and appraisal wells have been drilled to date, which discovered and appraised 5 oil accumulations in the BC-10 block. In June 2006 field development plans were submitted to the ANP for the development of the Ostra, Abalone and Argonauta-BW and Argonauta-ON fields. Phase 1 of the project comprises the development of the first three fields. Argonauta-ON is planned as part of Phase 2.
Given waterdepths, shallow below mudline hydraustatically pressurized reservoirs and oil properties a combination of long horizontal wells and artificial lift are required to deliver and maintain economic rates.
