Rupture-Resistant Filter Cake for Wellbore Strengthening

Lead Research Organisation: University of Cambridge
Department Name: Engineering


Fluid losses usually occur through fractures caused by the drilling pro- cess. To avoid this phenomenon,
a series of techniques has been developed to raise the integrity of the wellbore, stopping lost circulation
and allow drilling with wellbore pressures in excess of the fracture gradient. These techniques are called
wellbore strengthening. A typical example of wellbore strengthening mechanism consists of adding
participles to the drilling mud. When a fracture occurs these participles enter in the fractures and obstruct
it forming a bridge. However, in the last years a new theoretical wellbore strengthening mechanism has
been individuated which consists in the formation of a filter cake, which builds up on the wellbore walls
because the fluid pressure in the pore space in a permeable formation is lower than the borehole
This research will involve a combination of laboratory experiments and numerical analysis of the efficiency
of the filter cake in prevent fractures in the rock formation and their propagation. A parametric study will
be con- ducted to achieve specific filter cake properties (e.g. permeability, thickness and strength), which
increases the fracture gradient in the rock formation and consequently minimizes the fluid losses
during the drilling process.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/P510440/1 01/10/2016 30/09/2022
1834420 Studentship EP/P510440/1 01/01/2017 31/12/2019 Gianmario Sorrentino
Description Increasing the concentration of solid particles in the drilling fluid reduces the time needed to the external filter cake to builds up

A higher concentration of solid particles in the drilling fluid reduces the filtration flow through the substrate by increasing both the mass of internal and external filter cake

The pressure seems not to affect significantly the mass of the internal filter cake, whereas has a clear effect on external filter cake properties.
Exploitation Route Publishing paper
Sectors Energy

Description They have increased the knowledge about filter cake formation and properties. Since the aim is to use filter cake as wellbore strengthening techniques, it is essential understanding how it is possible to modify properties of the filter cake by changing the physical properties of the drilling fluid
First Year Of Impact 2020
Sector Energy
Impact Types Economic

Title Dynamic filtration apparatus 
Description In order to gain a deeper understanding of the effects of the individual parameters (pressure, flow rate, drilling mud composition and time) on the filter cake structure an experimental apparatus was designed. Such apparatus allows reproducing filter cake formation under cross-flow filtration conditions at different states of pressure and flow rate. 
Type Of Material Improvements to research infrastructure 
Year Produced 2018 
Provided To Others? No  
Impact The dynamic filtration loop designed makes possible to control and set independently pressure and cross-flow velocity during a test, in the literature has not been found any other dynamic loop for cross-flow filtration conditions which allows the same set of the operative parameters. This laboratory set up has been allowing me to investigate deeply and individually the effects of the operative parameters on the filter cake structure and helping to identify the optimum value of cross-flow velocity to maximize filter cake properties. 
Description International Centre for Advanced Materials: ICAM 
Organisation BP (British Petroleum)
Department BP Marine
Country United Kingdom 
Sector Private 
PI Contribution A better understanding of filter cake properties and developing to apparatus to measure filter cake strength.
Collaborator Contribution I have a BP mentor who has introduced me relevant concepts and skills, as well as providing a way for thinking about my research which can be interesting for industry purpose. My BP mentor is continuously monitoring the progress of my research experience (by regular calls and meetings).
Impact The primary aim of this Research Project is to assess whether the filter cake can provide an effective wellbore strengthening technique which does not rely on relatively large particles to reduce mud losses and limit fracture formation at higher pressures. The outcome of introducing filter cake formation as wellbore strengthening mechanism has the potential to impact drilling operations by overcoming the difficulties related to the conventional use of large particles and decreasing overall material cost related to drilling fluids. To achieve this result, extensive research work has been carrying out in order to provide: a better understanding of filter cake properties; explore new chemistries to obtain systems with improved fracture sealing and rupture-resistant properties of the filter cake, and provide a design methodology for filter cake as wellbore strengthening mechanism validated through experiments and simulations. This research work required the collaboration of a multi-skilled team. The physical, chemical and mechanical characterization of filter cakes is carried out by the researchers from the University of Cambridge. This group is divided into two sub-groups, the group I am working with is based at the civil engineering department which investigates the physical and mechanical properties of the filter cake, the other is based at the chemical engineering department which aims to improve drilling mud design in order to obtain filter cake with desired properties. At the University of Manchester, the third group will use X-ray Computed Tomography (XCT) to image the filter cake microstructure in 3D. The physical and mechanical characterization of the filter cake is carried out through laboratory experiments. Laboratory experiments have been carrying out in order to simulate the formation of the filter cake on the wellbore walls under dynamic filtration conditions, and a variety of techniques will be performed to evaluate the strength of the filter cake. A CT-scanner is employed to observe the microstructure and pore characteristics of the filter cake. Different drilling fluids have been tested in order to identify the optimum drilling fluid formulation in order to obtain filter cakes with desired properties.
Start Year 2017
Description I gave a presentation during Cambridge Science Festival 2018. The aim was to present my research topic to to a non-academic audience 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact The presentation I gave was a Pecha Kucha presentation style in which 20 slides are shown for 20 seconds each. The presentation was followed by a question and answer session. The purpose was to introduce my scientific topic to a non-academic audience. This gave me the opportunity to see my topic from a new perspective, identify the main questions and express them in a direct and simple way. The outcome for the audience was to be introduced to a new topic.
Year(s) Of Engagement Activity 2018