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The objective of this case study is to share essential learnings from the planning and execution of the first drilling and completion campaign in the Valemon field throughout the period of 2012-2017 with a total delivery of 17 wells. The case study will give an overview of the Valemon field, geology of the area and well design. The development of well trajectory became longer and more challenging as the geology targets moved farther away from the platform. Several major challenges and learnings were experienced during execution such as enabling one run strategy in 17-1/2" section, updating well path strategy to improve borehole stability, managing overburden gas responses in 12-1/4" section, and section target depth strategy for 12-1/4" section. Continuous learnings from sessions such as Improve Well on Paper (IWOP), Drill Well on Paper (DWOP), Subsurface Action Review (SAR), Subsurface After-Action Review (SAAR), operational procedures after action review, experience reports, and post well meetings enabled the project to reduce the time and cost per well. It took 160, 111, and 166 days respectively to complete the first three wells. The last well was delivered in 62 days. By the end of the campaign in November 2017, the Valemon project delivered four (4) extra wells compared to the original plan of thirteen (13) wells, while spending 500 million NOK-2017 (Norwegian Kroner with 2017 currency) or 60 million USD-2017 (United States Dollar with 2017 currency) less than the planned budget. Moreover, the entire drilling campaign was completed without any well control incidents.

Nowadays, the biggest challenges in the oil business are the cost of operations versus the sizes of the prospect. We are drilling smaller targets and over the last few years, rig cost, service company rates and materials have gone up significantly in accordance to the oil price. Industry is continuously searching for new technologies to make the drilling of well safer, more efficient and cheaper. This thesis explores the possibilities of combining existing technologies to solve these challenges.Drilling with casing (DwC) is using standard casing as the drillstring, and leaving it in place to case the well. It has almost no limitations and has a potential of saving 20 -30% of rig time by eliminating drillstring tripping and also minimizing downhole problems.With expandable technology, expanded casing can provide a larger diameter of the production casing. This can increase the productivity.Since both technologies have the same operational procedure, they could be combined into one operation. The concept is to use expandable casing as drillstring which will be expanded when the target depth is reached. To be able to expand the casing, one needs to drill with an underreamer to obtain a bigger hole and the BHA must be changed from a drilling into an expandable BHA.The conclusion of this thesis is that the drilling with expandable casing concept is possible. However, there are some technology challenges, especially on tools and on the strength of post expansion material. Limitations on drilling parameters such as: dog leg severity, RPM, mud properties etc also need to be considered to achieve a good expansion result.of 112 2The case example analyzed, indicates that we can save almost 23% of the operation time by running this combined technology. Expenses can be reduced through lowered rig costs and the operational risk can be mitigated. A better understanding of the technology and operational procedures will help to further reduce the risks and make the technology more acceptable. If this new method succeeds, there will have a high potential for cost savings, higher production and better well control. ACKNOWLEDGEMENTKnowledge is a power.It can break barriers, build the personality, and give us something to contribute to the society. I believe every single child brings their own hope, gift and inspiration. Teach and give them a chance and they will find their way. In this acknowledgement I would like to dedicate my special appreciation to these special people who has taught me a lot and given me chances: Table 3.1 -Rellwell System 41 Table 3.2 -Enventure connection properties 43 Table 3.3 -Case well parameter 43 Table 3.4 -Comparisons between connections with body 51 Table 3.5 -Pre and Post expansion-casing properties (Data is provided by Enventure) 53 Table 3.6 -Comparison of burst and collapse for pre-post expansion casing 55 Table 3.7 -Costs for conventional rig and equipments 56 Nowadays, higher oil price and world demands on oil and gas supplies, have allowed the oil companies increase their produc...