This paper presents design, testing, installation, and lessons learned with the world's first completely integrated managed pressure drilling (MPD) control system on a deepwater drilling rig. While previous MPD installations have included driller-operated systems, they all include additional human machine interfaces (HMI) and standalone control network components with limited use of rig data and limited to no interfaces to other critical drilling machines on the drilling rig. For the installation described in this paper, all MPD control functions were permanently installed on the main drilling control network of the drilling unit, providing direct access to high speed data from other drilling machines that influence the wellbore pressure. This includes the rig's mud pumps, top drive, and drawworks. Moreover, the MPD control system has the ability to actively control the drilling machines, thereby optimizing performance through coordinated control of mud pump, top drive, and MPD chokes during drilling and connections.
Pad drilling has become commonplace for North America shale development drilling, which requires tighter well spacing/separation and reduced anti-collision risk. A new digitally-controlled rotary-steerable system (RSS), extensively embedded with electronics, solid-state sensors and electrically controlled mud valve, has been developed specifically for drilling vertical and nudge well profiles from pads in North America. Unique technology includes a slow-rotating steering housing with four mud activated pads to apply side force at the bit. The pad activation is controlled using a novel mud valve driven by a low-power electric motor and gearing system. Activation of the steering pads and control of force to the steering pads is achieved using a small percentage of mud flow and approximately 500 psi pressure drop below the tool. The limited amount of mud flow passing through the mud valve eliminates internal wash issues and reduces repair costs.
The electronics measurement and control system are mounted in the slow-rotating steering housing and includes 3-axis inclinometers, 3-axis magnetometers, 3-axis shock sensors, 3-axis gyros, and temperature sensors. Additionally, compact drilling dynamics sensors are placed at the bit box to gather at-bit data to evaluate bit-rock dynamic interaction.
This paper will describe the unique features that allow the system to be reliable and cost-effective for high-volume land drilling activities. The RSS bottom-hole assemblies (BHAs) have been extensively instrumented with multiple downhole dynamics sensors, which reveal a challenging drilling environment unique to vertical drilling and nudge applications and show the performance of the RSS in this environment.
Copyright 2013, SPE/IADC Drilling Conference and Exhibition This paper was prepared for presentation at the SPE/IADC Drilling Conference and Exhibition held in Amsterdam, The Netherlands, 5-7 March 2013. This paper was selected for presentation by an SPE/IADC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers or the International Association of Drilling Contractors and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers or the International Association of Drilling Contractors, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers or the International Association of Drilling Contractors is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE/IADC copyright.
The identification of drillstring elements (in particular drillpipes) is currently performed in PETROBRAS using serial numbers imprinted somewhere on the body of the element. A procedure will be set up to establish effective control of these elements, such as accumulated cycles, accumulated footage, inspection reports and, particularly, accumulated fatigue. It is necessary to track each element along all campaigns in which it takes part by identifying its position on the drillstring, registering the mechanical parameters it is submitted, and registering the mechanical conditions of the borehole. Using the traditional imprinted serial number, it is difficult (or almost impossible) to keep a reliable log of each drillstring element in the rig site. The use of electronic chips attached to the body of these elements allows a fast, efficient, and reliable identification of each element through a unique key number. A manual reader is used to scan the chip and send the information to a local database at the rig site. The drilling parameters are obtained in real time through sensors distributed along the rig and sent to the database. At given time intervals, these data are used to calculate the fatigue each element was exposed to and accumulate the data in the database. A suitable mathematical model then is used for the fatigue calculation. Before being connected to the drillstring, each element is checked for accumulated fatigue and is accepted or rejected depending on the expected fatigue it will be exposed to in the campaign. Integrated databases on the operative units control the stock, inspection reports, supply, purchase, and discard of the drilling elements. Elements used before the implementation of the system are considered dummy elements with respect to the accumulated fatigue and are treated as usual. New elements are tracked since the first drilling operation. A period of several years (the average life span of the elements) is expected until all old, untracked elements are replaced by new, tracked elements. Among several benefits, this procedure is expected to significantly decrease drillstring failure due to mechanical fatigue, with consequent associated cost savings.