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.
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.
The fully automated fluid level measurement tool was developed recently. The paper describes the technical features of the tool and shows via case study the results of the field tests on various Electrical Submersible Pumps -ESPs and sucker rod pumps -SRP, running with and without Variable Speed Drive -VSD.The unique feature of this system is its fully automated and purely electronic functioning. The measuring device is enclosed, mounted on the casing valve, has a pressure rating of 350 bar (5000psi) and works with zero emissions on the environment (no outlet of casing gas).Compared with a conventional downhole pressure sensor, mounted on an ESP, the system is insensitive to high well fluid temperatures and simple to maintain due to its easy access on surface location. It additionally has a sampling rate of down to one measurement per minute. The measured fluid level data can be transmitted via SCADA system.The measurement tool enables to run a pump in a more safe way. It can be used to avoid pump off conditions and the resulting equipment damage. It can also be used to control a VSD to keep the fluid level in a well at a specific depth to avoid bottomhole flow conditions below the bubble point pressure. Due to the availability of online fluid level data, all kind of pumps (e.g. ESP, Sucker Rod, PCP, Jet Pump) can be operated safely at more aggressive production rates in order to mobilize more oil.Furthermore the vision and corresponding thoughts of acoustic well diagnosis, also a feature of the tool which is currently under investigation, are presented. IntroductionWhereas in free flowing wells it is relatively easy to get downhole pressure measurements, there are significant difficulties in wells which are on artificial lift. Compared to gas wells, in which memory gauges can be placed via slickline or wireline technology downhole through the tubing, this is not possible in sucker rod pumped oil wells because of the moving rods within the tubing.However, to measure bottomhole pressure also at artificially lifted wells is of special interest for both reservoir and production engineers. Conventionally the reservoir pressure and the well flowing pressure are calculated from the fluid level, which in turn is measured indirectly via acoustic method. An acoustic event is produced at the opened casing valve. Depending on the height of the available casing gas pressure, this event can be produced in different ways. If there are several bars of casing gas pressure available, the casing can be vented shortly to the atmosphere and closed immediately thereafter. So gas comes to flow at first. This flow is suddenly stopped, by closing a valve as shown in Fig. 1, which produces noise. If there is not enough casing gas pressure available, an external pressure source like a nitrogen gas bottle is connected to the casing valve. A short flow of pressured nitrogen is established into the casing and stopped suddenly, which produces noise once again.The acoustic wave propagates down the annulus and is reflected at every obstacle lik...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.