Abstract

Drilling shallow water directional wells with a reach vs. vertical depth ratio of 2.6:1 to a TVD of ~2200m has become a routine practice in the industry. Extended reach wells with this profile are no longer considered "extreme reach" and standard practices are being taught and implemented on a daily basis. An example of these standard extended reach practices include applications such as; controlled ROP's, cuttings bed clean-up cycles, high 3-6rpm mud rheologies, casing flotation, frequent drag tests and minimized backreaming. These practices have been tested and proven in numerous wells. However, following these standards does not always lead to the best results or most efficient well construction.

The Polvo project is a shallow water development located in the South part of the Campos Basin, offshore Brazil. During development drilling, both well design and drilling procedures stepped away from the extended reach "standards", resulting in improvement in drilling performance and wellbore quality. Several unorthodox drilling practices that were implemented on Polvo contributed to the drilling team setting various Brazilian records for longest extended reach wellbore and fastest ROP in two different hole sizes.

This paper intends to summarize the successes that were achieved on Polvo and detail the drilling practices that were implemented. The focus of the paper is on practices that went against industry standards and were proven to improve ROP, decrease trip time and improve casing running which provided a 35% overall reduction in well delivery time and cost.

Emphasis is placed on lessons learned that were applied to design and operations for the drilling of the Pol-O ERD well (Measured depth of 6,489m and step-out of 5,615 m). Pol-O is the Brazilian record holding well for total step-out and ROP in 8-1/2?? hole size.

As development of new fields in Brazil increases, the importance of efficiently drilling extended reach wells is becoming critical. The experiences and learning's on Polvo can assist the industry (expressly in the Campos Basin) with drilling practices to improve performance and decrease well delivery cost.

Introduction

The Polvo field is located approximately 100km off the southeastern coast of Rio de Janeiro state in the Campos Basin (Figure 1). The development area is situated within the BMC-8 block which was acquired in the 2nd round of lease auctions in Brazil by Devon Energy do Brasil (Devon). In May 2011, all of Devon's assets were acquired by BP Energy do Brasil (BP) whom currently owns and operates the Polvo field. All development drilling in the Polvo field takes place from a platform based drilling rig above a total water depth of 104m (NOTE: All depths listed in this paper are based upon RKB, therefore water depth is included).

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