The general idea of the research is based on the assumption that an oil well with an installed Sucker Rod Pump (SRP) emits a characteristic sound spectrum that can be assessed. Every change to the system (wear, beginning failures, etc) should be reflected in a corresponding change of the sound spectrum, creating thus a correlation. The scope of the research is to study noise, produced by a well and to find whether there is a relationship between emitted noise and a production state of the SRP. Correlation will be researched on the basis of dynamometer readings and actual production events. Noise represents a function of dynamic behavior of fluids, gas, downhole, and surface equipment. Sound created by this system is recorded in on-line mood with the help of a special device installed on the wellhead. The noise data then are transmitted, uploaded to a server, and available for processing. The analysis of the noise is based on Fast Fourier Transform (FFT), Power Spectral Density (PSD) estimation, together with statistical tools. This paper presents first tests that are done with the purpose to find a stroke’s signature. By signature it is meant characteristics that describe the stroke the best. They are best reporting features: PSD distribution, Noise Flatness, Root-Mean Squared, frequencies of maximum PSD, etc. The result of performed characterization with the help of signature concept, determines a pattern of SRP acoustically. This allows further application of acoustic diagnosis of SRP that helps identify many failures (like leaking tubing, standing and travelling valves, excessive loads, worn out rods, gas-lock, buckling, etc.) before they cause major damage or production loss.
Most of the crude oil is already recovered and discovering new oilfields tend to be challenging and difficult. Implementing an EOR method is essential to enhance the production life of mature oil fields and to make them economically more attractive. Especially, for heavy oil reservoirs chemical flooding is besides thermal methods promising. Only a limited number of alkali flood projects alone are reported worldwide. Phase screening represents the first step of experiments and gives information about the ability of various alkali solutions to generate in-situ surfactants at different concentration ranges. In this study, carbonate-based alkalis were screened on their effect on in-situ soap generation. Two oil reservoirs both located in the Matzen oil field (Austria) were observed, where an alkali flood project will be realized in the near future. In lab scale, were phase experiments with various concentrations of carbonate-based alkalis (sodium and potassium carbonate) screened at the water-oil-ratio 5:5. Formulations with synthetic and real softened brine were compared, using dead oil and viscosity-matched oil with cyclohexane. Samples were observed over time (100 days) to figure out their equilibrium at reservoir temperature. Afterwards large-scale samples were prepared and viscosity measurements performed. Potassium carbonate (K2CO3) is not well investigated in the literature as an alkali agent yet. It showed very promising results in all performed trials and generated remarkably more amounts of in-situ surfactants compared to Na2CO3, which is the most frequently used alkali performer. Additionally, in most concentrations the micro emulsion viscosities were lower. Thus, potassium carbonate might be an interesting candidate in future alkali applications.
A large fraction of artificially produced oil from mature, almost depleted reservoirs is lifted with sucker rod pumps. To increase the oil recovery factor under profitable conditions the objective is to reduce the operational costs, consequently decreasing the required number of maintenances and interventions. An essential cause of failures within rod pumps is buckling of the sucker rod string which occurs if the compressive load in individual rods exceeds a critical value. It causes a reduction of the volumetric efficiency and an increase of erosion and corrosion. The meantime between failures (MTBF) is relatively low and expensive changes of the rod string are required. This paper presents an approach to prevent buckling by tensioning the rod string during the whole pumping cycle with the tensioning device, which is integrated in the rod string below the pump plunger. In addition, an optimization of the tapered rod string is performed to reduce the mass of the reciprocating rod string. The system analysis is performed by a simulation of the downhole installation, which is verified by numerous dynamometer measurements, from the surface and downhole, of different operating oil wells. The result of the simulation is the distribution of the tension in the sucker rod string from the polished rod to the pump plunger. With this knowledge, a rod string with optimum usage of material strength and crosssections is designed. The tensioning device was already tested in a sucker rod pumped oil well in Austria. The result was a saving of electrical energy costs for the driving unit, and reduced number of workover operations. The tensioning device is simple but efficient and can be used within each sucker rod pump application. It prevents the system from buckling with a minimum amount of investment.
Oil contaminated sandy soil is considered to be an economical and environmental problem for the oil industry. The level of contamination is measured in Total Organic Carbon (TOC), which is a sum parameter to measure hydrocarbon compounds. TOC is considered to be the main contributor to the oil contamination in the field. The disposal process of oil contaminated sandy soil, commonly used in the current oil fields, attracts huge investment and resource. In an effort to clean the oil contamination of the soil from the oil field, an experiment program is designed to remove oil from the sand by using ultrasonic technology. The experiments with samples from an oil field in Austria indicate a substantial decline of the TOC value, measured by an Oil-in-Water Analyzer with quantum cascade laser (QCL) technology. Considering the physical feature of oil contaminated sand, a mechanical washing process is applied along with the ultrasonic technology in the experiment. The initial test of the experiment is to determine the real ultrasonic effect on the sample without washing effect in the treatment. The test proves that the combined process of mechanical washing and ultrasonic cleaning in two steps is an effective method to remove the oil from the sand sample. The ultrasonic technology alone can remove 88% of oil from the oil contaminated sand. The lowest TOC is achieved by mechanical washing following by the ultrasonic cleaning, which ultimately removed 99.5% of oil from the contaminated sandy soil. The new technology which is more safe, economical, reliable and environmental friendly will provide an alternative solution to remove oil from the sand not only to the oil industry, but for the society too.
Nowadays, the injection of dilute hydrolyzed polyacrylamide (HPAM) solutions after water flooding operations is a promising tertiary recovery method. However, the treatment of produced water containing breakthrough polymer plays a challenging aspect in the oil and gas industry. Ensuring good filterability of the produced water for further usage, either pressure maintenance or EOR application, is still a critical issue. Polymer loads in the produced water need to be expected, which can massively influence the separation efficiency of the water treatment system. Especially, the handling of polymer-containing water streams and finding the appropriate technology for the treatment, chemically or mechanically, has a decisive influence on performing a full-field roll out of polymer flooding activities. Aim of this work was to study the impact of back-produced polymer on the water treatment process and to reach the desired injection water quality. Therefore a water treatment plant in pilot scale was used. The unit simulates the main process steps of the water treatment plant Schönkirchen in the Vienna Basin (corrugated plate interceptor, dissolved gas flotation unit, and nutshell filter). The maximum back-produced polymer concentration, which can be handled within the system, was determined. Two different chemical sets (coagulant and flocculant) were tested, regarding their oil and solids removal ability, in presence of different polymer concentrations. At the end of the field study, one of these chemical sets was found, having a hydrocarbon removal efficiency of around 99% in presence of 30 ppm HPAM inlet concentration. Using this set, good removal efficiency and no plugging of the nutshell filter was observed even at high polymer concentrations. The other set led to plugging of the filtration system at relative low polymer concentrations of 8 ppm HPAM and the removal efficiency of hydrocarbons as well as polymer was poor. Based on these results, it can be assumed that the processes of the water treatment plant Schönkirchen are not negatively affected in the presence of up to 30 ppm polymer load in the inlet water stream.
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