Water Content In Crude Oil Research Articles

Terahertz-dependent evaluation of water content in high-water-cut crude oil using additive-manufactured samplers

The evaluation of water content in crude oil is of significance to petroleum exploration and transportation. Terahertz (THz) waves are sensitive to fluctuations in the dipole moment of water. However, due to the strong absorption of water in the THz range, it is difficult for the THz spectrum to determine high water content with the common sampler. In this research, micron-grade samplers for THz detection were designed and manufactured using additive manufacturing (AM) technology. Oil-water mixtures with water content from 1.8% to 90.6% were measured with the THz-TDS system using sample cells. In addition, a detailed analysis was performed of the relationships among THz parameters such as signal peak, time delay, and refractive index as well as absorption coefficient and high water content (>60%). Results suggest that the combination of THz spectroscopy and AM technique is effective for water content evaluation in crude oil and can be further applied in the petroleum industry.

Non-contact Measurement of the Water Content in Crude Oil with All-Optical Detection

Water content in crude oil is very important in an oilfield production logging system. A non-contact optical method, called all-optical detection, was proposed for measuring the water content in the full range of 0–100% in crude oil by a non-contact laser source and receiver (adaptive laser interferometer). The laser-induced ultrasonic P-wave velocities of three series of an oil–water mixture accelerated significantly from 1289, 1342, and 1343 m/s, respectively, to 1458 m/s with the increase of the water content from 0 to 100%. The theoretical values of the effective medium model were agreement with the experimental results of three series of an oil–water mixture.

A high resolution capacitive sensing system for the measurement of water content in crude oil.

This paper presents the design of a non-intrusive system to measure ultra-low water content in crude oil. The system is based on a capacitance to phase angle conversion method. Water content is measured with a capacitance sensor comprising two semi-cylindrical electrodes mounted on the outer side of a glass tube. The presence of water induces a capacitance change that in turn converts into a phase angle, with respect to a main oscillator. A differential sensing technique is adopted not only to ensure high immunity against temperature variation and background noise, but also to eliminate phase jitter and amplitude variation of the main oscillator that could destabilize the output. The complete capacitive sensing system was implemented in hardware and experiment results using crude oil samples demonstrated that a resolution of ±50 ppm of water content in crude oil was achieved by the proposed design.

The effect of water content in crude oil on the tribological behavior of screw pump’s stator rubber

It is worthy of studying the effect of water content in crude oil on tribological behavior of stator rubber, because the different water content would affect the swelling and wear of rubber. Compatibility of dewatered crude oil and water was observed after mixture of dewatered crude oil and water (called oil-water mixture) was mechanical stirred and statically placed. Static etching experiment of samples in oil-water mixture was performed using hanging patch test. Wetting contact angle of oil-water mixture on rubber surface was measured by contact angle meter. Tribological behavior of samples in mixture was measured using a ring-on-block tester. The result shows that when the water content is less than 15 %, water can blend with dewatered crude oil, and oil-water separation happens when water content was more than 15 %. With the increasing of water content in crude oil, Wettability of mixture and swelling increment of samples decrease. The wear loss of sample increases after treated by swelling experiment, and FKM owns better wear resistance than NBR.

A Semi-cylindrical Capacitive-based Differential Sensing System for Water Content in Crude Oil Measurement

A capacitive sensor based measuring system for water content in crude oil is presented. The non intrusive capacitive sensor is made of two semi-cylindrical electrodes which are mounted on outside of the glass tube. The tube is filled with sample under test. The capacitive variation is measured by taking advantage of big dielectric permittivity difference of oil and water. The semi-cylindrical capacitive sensor has ability to detect small capacitance variation (pF) and these variations can be converted into voltage by proposed differential interface circuit. The interface circuit is based on differential sensing technique. Such technique allows the removal of unwanted signals (e.g. temperature, background noise and systematic offset) because they affect both sensors in a similar manner. It however will not auto-compensate for the degradation in sensitivity. Hence, increased accuracy and linearity is achieved by differential sensing technique. Both simulation and actual hardware implementation confirmed the proposed system design. The system is experimentally tested for 0-30% water content in oil and achieved resolution of 0.39%

Experimental measurements of water content in crude oil emulsions by terahertz time-domain spectroscopy

We measured the water content (0.01%–0.25% w/w) in crude oil emulsions using terahertz time-domain spectroscopy (THz-TDS). To improve the precision and range of the measurements, we used 1 and 10 mm thick quartz cells. The experiments were performed at 20 °C and the THz wave was transmitted vertically to the samples and detected on the other side. The experimental results suggest linear relation for the THz absorption coefficient and the water content of the crude oil emulsions in the observed range. The linear dependence facilitates high-precision measurements of the water content of crude oil. This suggests the potential of THz-TDS in determining the water concentration in crude oil and borehole fluid identification.

Application of Neural Network in the Measuring System On-line for Water Content of Crude Oil

The aim of this study is to introduce a new way to measure the water content of Crude Oil. In this measurement system, capacitive sensor is used as sensitive element and BP neural network model is adopted to deal with data. Water content and temperature are used as input parameters to set up BP neural network model. By MATLAB simulation, a moisture content of crude oil is forecasted, so that the influence comes from temperature variation is compensated and the accuracy of the measurement result is improved.

Special Crude Oil Processing Research and Application of XinMu Oil Field

The main problem dehydration system of XinMu Oil Field at present is high dehydration temperatures,high the amount of demulsifier, increase output moisture content year by year and more and more frequent fluctuations.Through the reform to establish a dehydration subsystems,and composite demulsifier alone to deal with special oil to eliminate the influence of special crude oil to dehydration system.Filter out Daqing produced 169＃ demulsifier 150mg·L-1, when add oxalic acid 200mg·L-1 and fungicide 100mg·L-1 the demulsifier of good dehydration effect.After processing crude oil water content of less than 5%,sewage oil content of less than 20mg·L-1, which has solved the dehydration problems of troubled XinMu for many years.

Dynamic Inverse Model for Multi-Sensor Measurement System Based on Wavelet Neural Network

As traditional measuring method based on dielectric coefficients shows cross-sensitivity for multi-factor in the measurement of oil/water mixture, it can not meet the requirements of digital oilfield construction. Therefore, this paper presents an inverse model of wavelet neural network (WNN) combining with multi-sensing technology for achieving high-accuracy measurement of water content in crude oil. The simulation and experimental results demonstrate that the proposed method is available to eliminate the cross-coupling effects of multi-factors. The method has higher measurement accuracy and stronger generalization than the model built by BP-NN, and opens a versatile approach in nonlinear error calibration for multi-factors measuring system.

Optimization Design of Electromagnetic Conductance Sensor for the Water Content of Crude Oil inside Pipeline

In the measurement of water content of crude oil inside pipeline, the traditional electromagnetic conductance sensors cannot achieve the measurement of water content due to the influence of pipeline closure and electromagnetic shielding. In theory, the double-coil array electromagnetic conductance sensor can obtain the measurement of water content with low frequency sine signal as the motivation. However, its longitudinal resolution is too low and the characteristic is poor. The four-coil model has been established so as to improve the sensor vertical resolution. The simulation results indicate that the useful signal is concentrated in the internal of main coils, which plays a good role of longitudinal focus.

A microwave instrument for the continuous monitoring of the water content of crude oil

Since the effective permittivities of water and oil differ by an order of magnitude, it is shown that it is possible to measure their relative concentrations in crude oil by measuring the effective permittivities of the mixture at microwave frequencies. Dielectric mixture theory is used to show the relationship between the permittivity and the relative concentrations of two materials in a mixture. It is shown that equivalent results are obtained for the case of small concentrations of water in oil by using a perturbation theory analysis for a liquid cylindrical sample flowing through a resonant cavity. Results are presented for a sample enclosed in a thin-walled Pyrex tube with measurements taken for water concentrations in oil of 0-10 percent by volume. A practical instrument is described which uses a comparative technique for continuously comparing two samples of oil, one "dry" and one "Wet." Results show that this type of instrumentation can obtain sensitivities of 0.05-percent water content. The instrument is very simple, and has an output that can be readily adapted to automatic control applications.