Statoil operates the Troll Field in the Norwegian Sector of the North Sea and wished to run a deep sidetrack from the mother bore in a multilateral well that would exit through the 10-3/4-in. liner in the reservoir. The plan would have to address several new challenges, including an intelligent completion that would offer zonal isolation for four zones and dual pressure and temperature for all oil zones; these were not usual requirements for the standard multilateral wells in the field. Statoil had evaluated several zonal-isolation methods, and based on previous experience, they decided to use swellable packer technology. Since this would be the first intelligent-well completion in Troll field and the first ever for Statoil using feed-through swellable packers, a full scale test to qualify the technology was required. Swelling and differential-pressure tests were initiated using oil from the Troll field. Testing revealed that this type of completion actually would exceed the necessary requirements. The lower completion was designed with 7-in. inflow-control-device (ICD) mesh screens and three openhole swellable packers to isolate the reservoir into three separate oil zones and to separate the gas cap. The inner completion string was designed with three dual gauges, three 3-1/2-in. feed-through swellable packers, three 3-1/2-in. hydraulic flow-control valves, and a hydraulically operated gas-lift valve below the production packer to allow natural gas lift. The installation was performed from a semi-submersible rig without an HSE incident and ahead of plan. The well was put on production shortly thereafter, and zonal isolation was confirmed by selective closure of the flow-control valves. The paper will discuss the swellable packer design, qualification testing, planning, installation, and the results of this intelligent completion, which was the first in the Troll Field.

For the development of the HPHT gas field Dvalin a completion scheme using standalone screens is planned. To secure maximum clean-up and productivity, even after long term suspension, comprehensive lab testing of specific properties from drilling and completion fluids at downhole conditions, e.g. optimum bridging, minimizing formation damage, thermal stability and mobility was carried out. Furthermore, compatibility with production screens and formation fluids were verified. Drill-in fluid systems were advertised by different vendors to be compatible under the given initial reservoir conditions. For the sake of efficiency, the systematic test program consisted of a sequence of four test phases, where only successful fluids went to the next phase. The most important parameters of the test program were long-term high temperature stability and related sand screen compatibility, a detailed rheology characterization as well as complementary formation damage and return permeability tests. Finally, the additive concentrations of the awarded fluid system were systematically optimized to yield the least completion- and formation damage and highest return permeability.

The Dvalin gas field is located in the Norwegian sea on NCS and is operated by Wintershall DEA Norge. It is supported by two independent reservoir structures, Dvalin East and Dvalin West. The field was explored through wells 14S and 15S in 2010 and 2012, respectively. The field is characterized by dry gas, high CO2, high temperature (160 °C) and high pressure (SIWHP 620 bar). The targeted Garn sandstone has good reservoir quality, but with a high permeability contrast. The field development was sanctioned in 2016 and calls for a 4 well solution through a centrally located subsea template, producing gas back to the host platform Heidrun TLP 15 km away. Water depth at location is 380 m and targeted reservoirs are at 4140 m MSL (East) and 4240 m MSL (West). Production plateau rates are estimated to be approximately 106 MMscf/D (3 million std m3/d) per well where thin high-permeability zones within the Garn formation are expected to dominate the inflow. The lateral facies development is thought to be relatively homogenous throughout the field, thus S-shape wells falling off to vertical through the reservoir will ensure effective drainage. Sand failure is expected after short time of production and would increase the risk of erosion causing severe damage to well jewelry and production facilities. It has been decided to integrate sand screens as a means of downhole sand control as part of the primary lower completion design. The sand screens will offer sand control, erosion resistance, hot spotting resistance as well as robustness towards a full hole collapse during reservoir pressure depletion. As the subsea completions are carried out from a mobile drilling unit in harsh environments, protection of the sand control filter media during installation is of utmost importance. This paper will describe the selection process of sand control and qualification steps carried out to use ceramic screens as the stand-alone screen solution for successful deployment and integrity for the Dvalin field development