The plan forward is to continue building the flow loop. The first actions should be to or-der the remaining tank, solenoid, screen, and cuttings, decide on specific locations for the flow loop equipment and length of pipes, and plan the stand structure to support the tanks.
Delivery time could be a challenge and therefore it is desired to order equipment as soon as possible.
When the loop is built the plan is to conduct the previously presented experiments, analyze the results, and make a report documenting the results. A more detailed plan for each ex-periment must be prepared, describing in detail the different parameters to be controlled, the parameters to be measured, and an operational procedure. Mathematical models and algorithms for interpreting and evaluating the acquired data also need to be investigated.
When the planned experiments are completed, there are other possible experiments to be run. Adding a bend in the test section or installing an obstacle for cuttings to collide into would be similar to the situation for sand production monitoring by the ClampOn sensor.
Another option is to replace the solenoid hammer by installing a vibration unit that can send specific frequencies into the pipe and see if that gives better results. Also, as men-tioned previously it would be interesting to simulate hole cleaning, by gradually removing cuttings from the flow. Features would have to be added to the flow loop to make this possible, as cuttings would have to be added in a controlled matter.
For future projects with the flow loop, there are many possibilities. A natural development is to include mud and look at three-phase flow, both with and without cuttings. As drilling mud can be both water-based and oil-based it would be wise to look at how measurements done with different mud types look. It would also be interesting to look at the effects of changing the viscosity and temperature of the fluid. Mud return from the well will have a higher temperature than room temperature, which will be the temperature of the planned project. Viscosity is an important property of the drilling mud for hole cleaning purposes.
Investigating the effects of changing the viscosity is a possibility.
To resemble a rig located flow line between the well and the shakers it is interesting to tilt the test section and look at how inclination affects the measurements. To correlate to MPD or production measurements the ball valve after the venturi meter could be closed to increase the pressure in the test section. It would require doing a thorough check of all the included equipment and sensors to make sure they can withstand the increased pressure within safety limits. For many acoustic type sensors, the wall thickness and pipe diameter create limitations. Too large wall thickness will disturb and weaken the signals. Too small pipe diameters will lead to high uncertainty as the travel length of the signals are too short.
Changing the wall thickness and pipe diameter of the test pipe section could be good ex-periments to identify these limits for the specific set-up.
Chapter 22
Discussion
The ClampOn project is extensive, and the planning phase reflects this. The design of the flow loop has been altered many times during the planning phase and is due to continue changing as more information about the different parts is acquired and when building of the flow loop recommences.
Several learnings have been acquired during the project planning phase. The understand-ing of the basics behind the offshore mud circulation system has been improved. Knowl-edge about the different equipment was developed when creating the design of the flow loop. Performing the risk analysis is a safety measure for facilitating a safe project, but was also a great tool for project planning. The complexity of the project increases as more details are computed. The biggest learning from the project planning phase is that planning takes more time than originally thought, especially when several participants are involved.
Many decisions are dependent on previous decisions. In the beginning, the Coriolis meter was a large planned expense and many of the design parameters of the flow loop were based on the Coriolis parameters and could not be decided until a type of Coriolis meter was set. The decision to go with a simpler flow meter instead of the Coriolis meter sig-nificantly reduced the costs of the project, but also the possible level of parameter control.
Including a Coriolis meter at a later time should be possible without too many alterations of the loop.
During the building phase, it became clear that not all events, required parts, and solutions were predicted in the planning phase. As the building phase progressed, new challenges arose and had to be managed. The learning by doing approach means that some mistakes might happen, which can result in a setback for the project. As planning of a project of this complexity and building of a flow loop were performed for the first time, commencing the building phase before the planning phase is 100 % completed was necessary. The experi-ence ahead of the project was not sufficient to make up a perfect project plan straight away.
For the future project execution phase unforeseen events might occur and to make sure the project is done in due time the start-up of the project should be as soon as possible. The
goal should be to complete the project in due time with useful results without exceeding the budget and to avoid HSSE incidents.
Even though the flow loop set-up will be a simplification compared to a real drilling fluid circulation system, it has potential for acquiring useful results. Many different experiments can be run as there are multiple parameters to vary. As discussed in Part I of the thesis, the desire to develop new and better solutions for flow measurements is highly present in the drilling industry. As mentioned in chapter 4, acoustic measurements can be utilized for many purposes, including measurement of flow rate, leak flow detection, and downhole monitoring during hydraulic fracturing stimulation. For many of the acoustic technologies described the complexity of the drilling fluids and harsh drilling environments are chal-lenging. The ClampOn SandQ Monitor is already in use in the oil and gas industry to monitor the amount of sand in the well stream during production, and it would be inter-esting to see if it has potential for flow measurements also during drilling. If the results for the ClampOn Monitor are not satisfactory, the decision of creating a flexible flow loop design for easy implementation of new equipment still enables the flow loop to be used in a variety of experiments in the future.
Chapter 23
Conclusion
Project planning is an extensive and time-consuming process. The plan becomes more complex as it is developed, due to new ideas arising and the level of details increasing.
This was also accurate for the flow loop project. As many of the sensors were already purchased by the department, the main challenges were choosing new equipment to fit the existing equipment and to be able to simulate offshore conditions. Selecting the right type of Coriolis meter was a large part of the planning, as the main dimensions of the flow loop were based on the Coriolis parameters and because of the high cost of the Coriolis meter.
When the decision was made to use a simpler flow meter instead of the Coriolis, the cost of the project was severely reduced. The main learning acquired during the planning phase is that planning takes longer than anticipated. The level of complexity also increased during the building phase. The learning by doing approach led to progress in the building phase.
As discoveries were made, it was necessary to take a step back and evaluate the occurring situations. Plans were then adjusted or new plans had to be made.
As many of the current technologies for flow measurement have challenges and limita-tions, it is natural to look for new and better solutions. The ClampOn SandQ Monitor is already in use for flow measurement during production, and it is therefore interesting to investigate the potential of the monitor in the drilling process. A successful result of a future ClampOn SandQ Monitor project would be to determine if the sensor has poten-tial for flow measurements during drilling. For the project to be completed the planning needs to be finalized, the remaining parts need to be ordered and the building of the loop completed. The flexibility of the loop, both for running a variety of experiments with the current design and the high potential for easy implementation of new equipment, ensures that the flow loop can be of value in many future projects in the department laboratory.