Thesis (M.S.)--Ohio State University, 1982. / Includes bibliographical references. Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--Ohio State University, 1981. / Includes bibliographical references (leaves 351-358). Available online via OhioLINK's ETD Center.

Liquid loading in producing gas wells is the inability of the produced gas to remove produced liquids from the wellbore. A review of existing flow loops worldwide revealed that specialized areas of research such as liquid loading in gas wells are still lacking dedicated test facilities. This project presents the design of a new dedicated facility to be located at the TowerLab at the Richardson building with adequate operating conditions to reproduce the flow regimes encountered prior to and after the onset of liquid loading in gas wells. The facility consists of a compressed air system, pipelines for air and water, a pressure vessel containing glass beads, an injection manifold, and flow control and monitoring devices. Our results show that three compressors working in parallel is the most technical and economic configuration for the TowerLab based on the overall costs provided by the supplier, the footprint but most importantly the flexibility. The design of the pressure vessel required a cylindrical body with top and bottom welded-flat head covers with multiple openings to minimize its weight. The pipelines connecting major equipment and injection manifold located at the pressure vessel were selected based on the superficial velocities for air and water. These values also showed the need for independent injection using two manifolds instead of commingling flow through a tee joint. The use of digital pressure gauges with an accuracy of 0.05 to 25% and coriolis or vortex meters to measure air flowrate is also suggested. For the water line, installation of turbine meters results in the most economic approach.

Liquid loading is a serious problem in gas wells. Many proven artificial lift methods have been used to alleviate this problem. However, a complete workflow to determine the most suitable artificial lift method for given well conditions does not exist. In 2008, Han Young Park presented his thesis of decision matrix tool using a decision tree technique for data mining that determined the best artificial lift method for liquid loading in gas wells from seven artificial lift methods: plunger lift, gas lift, ESP, PCP, rod pump, jet pump, and piston pump. He determined the technical feasibility and the cost evaluation of these seven techniques. His workflow consisted of three rounds. The first round was the preliminary screening round. By using all input well conditions, the impractical techniques were screened out. In the second round, all the techniques from round one were graded and ranked. In the third round, the economic evaluation was performed by using cost for each artificial lift method and assuming the constant additional gas production per day to determine net present value (NPV) and internal rate of return (IRR). In this thesis, we propose an extended workflow from the Han-Young’s thesis for the decision matrix tool. We added integrated production simulations (reservoir to wellhead) step with commercial software in between the second and third round. We performed simulations of the various artificial lift methods to see the additional gains from each technique. We used the additional gas production resulted from simulation to calculate economic yardsticks (the third round), NPV and IRR. Moreover, we made the decision matrix more complete by adding three more liquid unloading techniques to the decision matrix: velocity string, foam injection, and heated tubing. We have also updated all screening conditions, the technical scores, and the costs for the decision matrix from the previous study using literature reviews, information from the project’s sponsor, information from service company and our own judgment. The aim of the decision matrix is to allow operators to screen quickly and efficiently for the most suitable artificial lift method to solve the liquid loading problem under given well conditions.

Field-proven solutions already exist to reduce the loss of gas production when liquid loading begins to occur. However, the choice of remedial technique, its feasibility, and its cost, vary considerably depending on a field's location, size export route, and the individual operator's experience. The selection of the best remedial technique and the timeframe within which the remedial action is undertaken are critical to a project's profitability. Although there are literature reviews available regarding solutions to liquid loading problems in gas wells, a tool capable of helping an operator select the best remedial option for a specific field case still does not exist. This thesis proposes a newly developed decision matrix to screen the possible remedial options available to the operator. The matrix can not only provide a critical evaluation of potential solutions to the problem of liquid loading in gas wells vis-à-vis the existing technical and economic constraints, but can also serve as a reference to operators for investment decisions and as a quick screening tool for the selection of production optimisation strategies. Under its current status of development, this new tool consists of a decision algorithm built around a decision tree. Unlike other data mining techniques, decision trees quickly allow for subdividing large initial datasets into successively smaller sets by a series of decision rules. The rules are based on information available in the public domain. The effectiveness of the matrix is now ready to be tested against real field datasets.

In captivity the diversity of prey items for obligate insectivores is limited and nutritionally inadequate, leading to nutrient deficiencies. Zoological institutions utilize gut-loading, an insect supplementation technique, to compensate for these nutrient shortcomings. This study developed a gut-loading diet (GLD) to enhance the nutritive quality of the domestic house cricket (Acheta domestica) for insectivorous amphibians and reptiles, with the requisite that it also met cricket foraging and palatability needs. Gut-loaded cricket analysis established its effectiveness such that the targeted level of most nutrients required by the end consumers were met after consuming the diet for 24 hrs (Ca:P of 1.127; vitamin A (retinyl acetate) level of 12,607 IU/kg; vitamin E level of 342 IU/kg and a linoleic fatty acid level of 4.62%), peaking at 2 days for some and remained above targeted amounts for at least 4 days. A list of cricket gut-loading optimization husbandry procedures has also been recommended.

No description available.

No description available.

The Design of structures under dynamic loading is a demanding subject in safety of engineering design since conventional static failure criteria are unable to deal with structures under transient loading. This work is a contribution to this significant phenomenon to investigate the response and failure of structures to pulse loading. An experimental rig has therefore been designed to achieve the target. A series of experiments has then been carried out to investigate the structural failure under pulse loading using a shock tunnel. A non-linear transient analysis of plates and cylindrical structures under pulse loading has also been performed using ANSYS finite element code in order to introduce a failure criterion for these specific conditions. A large-scale heat exchanger under pressure pulse loading was also analysed experimentally and numerically. The impulsive load has been chosen to be above the static design pressure to investigate the effects of impulsive load and its duration on the plate failure. A critical curve is presented to determine the critical pulse loading and its duration for structures. The relations between the transient pressure loading, its duration and the natural frequency of the structure are also explored. It is indicated that the value of the impulsive load on structures may exceed the static design pressure without structural failure. Both experimental work and numerical analyses suggest that the design criteria for structures under dynamic loading are more flexible than those under static loading in which no freedoms in deviation of any simple yield criterion exist. It is concluded that using a proper failure criterion for any specific problem can increase safe working region of the structures which leads to economical and safe dynamic design of structures.

No description available.