This paper describes the development of a low-solids mineral oil-based fluid and its successful application as a drill-in and completion fluid in a multilateral (MLT) well on Statoil's Aasgard field, off Mid-Norway. The introduction of highly complex technology, such as multilateral well design with long horizontal reservoir sections, demands a strong focus on the drilling fluid characteristics. Recent field experience showed that conventional oil-based mud (OBM) systems had limitations, when used in a demanding downhole environment influenced by elevated temperatures and ambitious drilling and completion objectives. This resulted in lower than expected drilling efficiency and well productivity. Accordingly, a development program was instituted to qualify a new high temperature OBM that possessed reduced formation damage potential and superior bridging characteristics while remaining thermally stable. The candidate fluids investigated were OBM of three different types:standard OBM with a mineral base oil,OBM with a linear paraffinic base oil anda low-solids (LS) OBM. The latter was based on an emulsion with a heavy calcium bromide brine as the internal phase and a mineral base oil as the external phase. Bridging materials and organoclay for viscosity were added as the only solids materials. The results of the qualification programme showed that the LS OBM exhibited superior sag stability and much higher return permeability values as compared to the two other oilbased alternatives. The field application of the fluid was very successful. And the Aasgard subsurface team managed to drill and complete a total well path length of about 4900 m. The well was drilled and completed 37 days ahead of plan and produces with a productivity index as expected. Introduction The Aasgard field development is located in the Haltenbanken area off mid-Norway and comprises three fields - Smørbukk, Smørbukk South and Midgard. The field was developed in the late 1990s with a subsea production system with two production facilities, Aasgard A (FPSO) and Aasgard B (semi submersible gas processing platform). In addition a storage and offloading vessel (Aasgard C) receives the liquid production from Aasgard B (Fig. 1). The three different fields have widely different fluids and reservoir quality, and accordingly, wells are completed differently. The Smørbukk reservoir is the most challenging with a reservoir temperature of 165°C in the deepest zones. Smørbukk South is somewhat shallower than Smørbukk and the reservoir temperature is 150°C in the deepest zones. The Midgard field is different again from both Smørbukk fields-the reservoir temperature is lower at 90°C and a different approach to drill and complete the reservoir has been adopted. This paper concentrates on the two Smørbukk fields. Additional information on geology, reservoir engineering aspects and early production strategies of the Aasgard field and field-specific technology challenges was reported by Haaland et al. (1996)1. Well constructions in the early development phase followed a rather straightforward design. In general, the Smørbukk wells were drilled vertical or deviated and the Smørbukk South wells were drilled horizontal. Completions consisted either of cased and perforated reservoir sections (Smørbukk) or openhole completions with pre-drilled liners (Smørbukk South). All Smørbukk wells are commingled wells, the Smørbukk South wells targeted the Garn formation only. Although experience with multilaterals (MLT) was limited in the mid-90s, multilateral wells with long horizontal sections were part of the long-term field development plan for production of the Ile and Tilje formations on Smørbukk South 1. MLTs were considered essential to maximize drainage from a reservoir with rather poor quality. With increasingly demanding well construction plans, work processes and system components for drilling and completion operations need to be continuously revised. Under high-temperature conditions all elements in the well construction process must be highly redundant and compatible.

Step changes in the area of Well Integrity is often based on HSE, production regularity and intervention cost. Well Integrity is a relatively new area of expertise, where small and larger quantitative and qualitative improvements can be expected. With change in technology comes procedural changes. With more significant improvements comes organizational changes. This paper shed some lights on some improvements in the pipeline for future Well Integrity Management. Some step changes are more evident as new equipment are qualified. Other improvements may be more intangible, like procedural or organizational changes. An overview has been made per phases a well is subjected to, in an approach to understand where it is likely to see progress in the area of Well Integrity. The overview follows a typical life cycle of a well to map out the processes and work where a well's barriers, integrity and containment are either planned, established or active. One important issue learned from making an overview of the Well Integrity activities through the life cycle of a well is how the work is divided between different groups in an organization with different responsibility and Key Performance Indicators (KPIs). Updating and reporting integrity status, providing performance and reliability data across lines is in itself a challenging task. The Integrity of a well is often tied to the capacity to contain fluids. The processes which happen on the outside of the barrier envelopes are also important. It can be gas migration leading to sustained casing pressure, exposure to mobile corrosive fluids, subsidence or formation collapse. Traditionally, monitoring pressure in the production annulus has been the main indicator of integrity and source of information. Many operators acknowledge that monitoring the other annular pressures are important and have long desired automatic surveillance of the next annulus.

This paper outlines an extract of a software model for digitalization of the processes supporting upstream activities for onshore and offshore fields. Digitalization in this context means full automation of planning and a step change in the daily well integrity work. The planning process will produce digital programs and proceduresunderstandable to humans and computers. The software comprises building blocks for every engineering calculation. These are interlinked andconstructed such that their planning capacity can be improved by the users. Today, humans drive every step in engineering and planning. Digital well planning and operations will shift the role of humans towards feeding the planning process with experiences in digital format. Changing from text based learning to digital experience will improve planning and operations. Digitalization can also provide digital standards, governing documentation and automate administrative routines such as invoicing. Visualization of wells, their components, barrier envelopes and elements from plan to "as installed" will form a 3D interactive interface where users of different roles can retrieve information and see relevant engineering, modelling and integrity status. The software is planned to be cloud based and exploit local graphics hardware for optimal performance and response. This article gives an introduction to the planned functionality of a new Digital Life Cycle Well Integrity Model (LCWIM) which is under development. In addition to an overview of the functionality, digitalization is exemplified by automation of one of the LCWIM modules, namely casing wear prediction. The LCWIM will produce digital programs and procedures, which is a foundation for the next step in digitalization: automation of the drilling process. The focus of this paper is to depict a digital work process concerning well planning giving input to the operational phase and well integrity.

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Digital well planning, construction and maintenance have a lot of potential for cost reduction and improved HSE. Developing a software model to replace many of the tasks performed by humans can reduce administrative tasks and enables more focus on the quality of plans and operations. One single model to overlook engineering and activity through the life cycle of wells from the planning phase, through construction, production, maintenance to the final plugging unlocks many potential improvements. One possible feature for a Life Cycle Well Integrity Model (LCWIM) is to embed industry standards to supply guidance and recommendations during the life cycle of a well. Changing the format of standards so both computers and humans understand their content can benefit the planning and operational phases of well construction, intervention, production and finally plugging. Typically, standards are used broadly in the planning phase. However, in the later phases of the life cycle of the well, it is often more difficult to accommodate both changes in operations and updates to industry standards. Embedding the industry "best practice" into software for planning well construction and maintenance, can prevent potential human errors and ensure an appropriate well construction. Having standards as "digital eye" on the engineering and well construction parameters can help to ensure safer operation and help to ensure that no regulations are overseen due to human error. Standards can be considered a collection of experiences gathered over decades in the industry, and they represent the common ground for description of methods and procedures for safe and sustainable operations. When digital well planning gradually replaces the traditional manual planning processes, the vast experience of standards can support engineers more actively and directly compared to text documents. This paper describes an approach to merge the digital version of a standard into the LCWIM so it actively provides relevant information to ongoing operations similar to a help function. The user would experience this as "relevant information" by just a mouse-click. The method of choice elaborated in this article shows a life cycle standard in the shape of an active support module to the LCWIM. The reasons behind the selected approach is twofold: (1) LCWIM is a life cycle tool, which incorporates life cycle standards to support all activities in all phases, (2) Standards support LCWIM by verifying that tests and procedures are in compliance. The focus of this paper is to demonstrate how a life cycle standard like the NORSOK D-10 Rev. 4, June 2013 can be completely digitalized to take an active part in planning and operations. The scope is limited to section 5.6 "Casing design" with elaboration of section 5.6.3 "Load cases" to stepwise show one way the standard can become interactive.