Traditional fracture completion systems are often inefficient. They suffer from friction and pressure losses, large hydraulic horsepower requirements, premature openings with frequent screen-outs, and time-consuming multiple downhole operations. A monobore, or a single size ball system with disappearing seats, addresses many of the drawbacks to a traditional fractured completion. By minimizing friction losses and pressure drops, monobore systems increase fracture effectiveness throughout the well while decreasing hydraulic horsepower requirements at the surface by up to 60%. The system delivers higher flow rates, lower stimulation pressures, reduced surface pressures, less equipment, smaller pad sizes and higher safety at less cost. In this paper the authors will describe the design and advantages of a monobore system with one size ball and disappearing seats.

Greater Plutonio is a 5 field subsea, deepwater project, located offshore Angola. Development began in 2005 and 38 wells have now been completed in highly permeable but poorly consolidated Oligocene reservoirs. Production commenced in October 2007 and is supported by injection of over 350mbd of water into 21 water injectors, predominantly completed with Stand Alone Screens. As the fields have multiple stacked reservoirs, dual zone downhole flow control (DHFC) is advantageous in many water injectors as it allows better control of injection conformance and / or a reduction in well count. During the design phase, it was recognized that although much of the hardware for DHFC systems for water injectors was field proven, the ability to create a long term seal between zones with openhole completions, especially in the deepwater environment, was a significant challenge that had not yet been addressed by the industry. The key challenges were: High differential pressure rating (3000psi). Achieve a robust seal in non-circular wellbores. Large axial load resulting from temperature reduction and differential pressure (>400,000lbs). Large number of injection and shut-in cycles occur over life of well. Large changes in temperature and consequently axial loading occur with each cycle. Following a technical evaluation, a novel dual cup packer concept with integral sliding movement joint and openhole packer slips was selected. This was followed by a 2.5 year rigorous design and qualification period prior to field installation1. 8 DHFC water injection wells have now been installed in Greater Plutonio, and downhole pressure data shows that the cup packers are providing robust high pressure seals after 3.5 years of high rate water injection. The cup packer system has produced a step change in openhole packer technology that has facilitated installation of reliable DHFC water injection wells at scale in the deepwater environment.

There is a very significant move today towards multiple zone fracturing operations in a single well where zones are separated and individually fractured, particularly in shale gas completions. This technique has to date involved the use of ball seat activated sliding sleeves located across each zone, with consequent reductions in internal diameter (ID) and attendant flow characteristic limitations or selective perforating, fracing and isolation with a bridge plug in a cemented casing string while working up the hole. Both approaches involve many downhole intervention operations such as perforating, shifting sleeves, running plugs and subsequently milling them up with coiled tubing (CT) intervention, all of which extend the length of the operation and add to the overall costs. To simplify the process of multiple fracturing operations, especially in open hole, a new approach has been designed which uses Radio Frequency Identification (RFID) techniques to remotely operate sliding sleeves. The number of sleeves that can be run in a well using this technology is essentially unlimited, each one having the same ID and a unique electronic address which allows it to be operated remotely at will. This approach provides for a means of making considerably more zones available for treatment without physical intervention with CT or wireline and thereby speeds the multiple frac operations and allows for wellbore clean up from the toe to the heel of the well. In this paper the authors will describe the design and operation of the RFID operated frac sleeves and the advantages they provide. They will go on to detail the Worlds’ first remotely operated horizontal openhole frac completion where frac sleeves and swell packers were used in an extended reach horizontal shale gas well.