Abstract
In the last couple of decades a new design for an oil well emerged, known as the monobore or monodiameter oil well. The oil well design is made possible due to a recent developed technology, the downhole expansion process. The technology opened up a pathway for the oil well to have from earthsurface all the way down to the reservoir, an approximate uniform inner diameter. In the design, in a repetitive procedure, expandable pipes are positioned in a borehole and expanded to allow another priorto
expansion sized expandable pipe to be positioned further downhole. Expansion of the pipes occurs in a borehole with inbetween the pipe and the soil borehole fluid saturated cement. The expansion of the pipe will compress the saturated cement, that will result in free fluid separation. The degree to which this separation of fluid will occur will depend upon a set of system variables, such as cement porosity or expansion speed and will lead to a potential failure behavior where the oil well would no longer be operational. In this project the consequential behavior of the expansion process with respect to the cement sheath is investigated.
To advance the development of the oil well and establish a failsafe design, the problem is dismantled in three relevant experiments for which individual designs are developed. Prior to the development of each experimental design, a theoretical and numerical analysis is performed that are utilized as a tool to establish the framework for each design. It is demonstrated in a simple onedimensional model that throughout expansion of the pipe and compression of the cement sheath, the free fluid that emerged from the saturated cement has a preferential flow direction. Due to the former finding a more extensive model was developed to investigate the effect of fluid accumulation at the interface of the expandable pipe and cement sheath. The annulus model granted a parametric study of the expansion process and the cement sheath and established the foundation and framework for three distinct designs of experiments, the hydraulic bond strength test, the cement radial deformation test and the smallscale expansion test.
expansion sized expandable pipe to be positioned further downhole. Expansion of the pipes occurs in a borehole with inbetween the pipe and the soil borehole fluid saturated cement. The expansion of the pipe will compress the saturated cement, that will result in free fluid separation. The degree to which this separation of fluid will occur will depend upon a set of system variables, such as cement porosity or expansion speed and will lead to a potential failure behavior where the oil well would no longer be operational. In this project the consequential behavior of the expansion process with respect to the cement sheath is investigated.
To advance the development of the oil well and establish a failsafe design, the problem is dismantled in three relevant experiments for which individual designs are developed. Prior to the development of each experimental design, a theoretical and numerical analysis is performed that are utilized as a tool to establish the framework for each design. It is demonstrated in a simple onedimensional model that throughout expansion of the pipe and compression of the cement sheath, the free fluid that emerged from the saturated cement has a preferential flow direction. Due to the former finding a more extensive model was developed to investigate the effect of fluid accumulation at the interface of the expandable pipe and cement sheath. The annulus model granted a parametric study of the expansion process and the cement sheath and established the foundation and framework for three distinct designs of experiments, the hydraulic bond strength test, the cement radial deformation test and the smallscale expansion test.
Original language  English 

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Award date  26 Sep 2019 
Place of Publication  Enschede 
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Publication status  Published  26 Sep 2019 