Xingbin Liu

Conductance Sensor for Measurement of the Fluid Watercut and Flowrate in Production Wells

A new type of conductance sensor is designed to measure both the flowrate and the water cut simultaneously in oil/water two phase flow in oil production wells. With the conductance sensor, the watercut is obtained by the ratio of the conductivity of the oil/water mixture to that of the water, and the flowrate is gotten by cross‐correlation flowrate measurement, which can figure out the transit time of the fluid flowing noises passing through the upstream and downstream sensors in the conductance sensor. In the paper, the principles of measuring flowrate and watercut are introduced. The results of dynamic experiment in multiphase flow loop and the application in field of the technology are introduced in it too.

The Finite Element Analysis for a Mini-Conductance Probe in Horizontal Oil-Water Two-Phase Flow

Oil-water two-phase flow is widespread in petroleum industry processes. The study of oil-water two-phase flow in horizontal pipes and the liquid holdup measurement of oil-water two-phase flow are of great importance for the optimization of the oil production process. This paper presents a novel sensor, i.e., a mini-conductance probe (MCP) for measuring pure-water phase conductivity of oil-water segregated flow in horizontal pipes. The MCP solves the difficult problem of obtaining the pure-water correction for water holdup measurements by using a ring-shaped conductivity water-cut meter (RSCWCM). Firstly, using the finite element method (FEM), the spatial sensitivity field of the MCP is investigated and the optimized MCP geometry structure is determined in terms of the characteristic parameters. Then, the responses of the MCP for the oil-water segregated flow are calculated, and it is found that the MCP has better stability and sensitivity to the variation of water-layer thickness in the condition of high water holdup and low flow velocity. Finally, the static experiments for the oil-water segregated flow were carried out and a novel calibration method for pure-water phase conductivity measurements was presented. The validity of the pure-water phase conductivity measurement with segregated flow in horizontal pipes was verified by experimental results.

Design and numerical simulation on an auto-cumulative flowmeter in horizontal oil–water two-phase flow

In order to accurately measure the flow rate under the low yield horizontal well conditions, an auto-cumulative flowmeter (ACF) was proposed. Using the proposed flowmeter, the oil flow rate in horizontal oil-water two-phase segregated flow can be finely extracted. The computational fluid dynamics software Fluent was used to simulate the fluid of the ACF in oil-water two-phase flow. In order to calibrate the simulation measurement of the ACF, a novel oil flow rate measurement method was further proposed. The models of the ACF were simulated to obtain and calibrate the oil flow rate under different total flow rates and oil cuts. Using the finite-element method, the structure of the seven conductance probes in the ACF was simulated. The response values for the probes of the ACF under the conditions of oil-water segregated flow were obtained. The experiments for oil-water segregated flow under different heights of the oil accumulation in horizontal oil-water two-phase flow were carried out to calibrate the ACF. The validity of the oil flow rate measurement in horizontal oil-water two-phase flow was verified by simulation and experimental results.

Novel Downhole Electromagnetic Flowmeter for Oil-Water Two-Phase Flow in High-Water-Cut Oil-Producing Wells

First, the measuring principle, the weight function, and the magnetic field of the novel downhole inserted electromagnetic flowmeter (EMF) are described. Second, the basic design of the EMF is described. Third, the dynamic experiments of two EMFs in oil-water two-phase flow are carried out. The experimental errors are analyzed in detail. The experimental results show that the maximum absolute value of the full-scale errors is better than 5%, the total flowrate is 5–60 m3/d, and the water-cut is higher than 60%. The maximum absolute value of the full-scale errors is better than 7%, the total flowrate is 2–60 m3/d, and the water-cut is higher than 70%. Finally, onsite experiments in high-water-cut oil-producing wells are conducted, and the possible reasons for the errors in the onsite experiments are analyzed. It is found that the EMF can provide an effective technology for measuring downhole oil-water two-phase flow.

Novel Four-Electrode Electromagnetic Flowmeter for the Measurement of Flow Rate in Polymer-Injection Wells

In this article, a novel four-electrode electromagnetic flowmeter (EMF) is proposed for flow rate measurement in polymer-injection wells. The ideal response model of the four-electrode EMF is established. In this model, the weight function and intensity of magnetic field are both derived, according to which numerical calculations are conducted. The calculation results show that in the annular area between the flowmeter and oil tubing, the weight function and magnetic field are both symmetrically distributed near the measurement electrodes and magnetic poles, respectively, and are rapidly attenuating along the radius direction. The potential difference is calculated for several kinds of flow velocity profiles in the annular area, and the calculation results show that the output of the four-electrode EMF is sensitive to the distribution of the flow profile. The experimental results obtained by using the multiphase flow loop facility show that when the four-electrode EMF is used in polymer solutions, the instrument constant of the four-electrode EMF differs from that used in tap water and remains unchanged with the concentration of the polymer solutions. The flow patterns of tap water and polymer solutions are various, leading to the change of the instrument constant of the four-electrode EMF. On-site experiments show that the four-electrode EMF is suitable for the polymer-injection wells developed in short durations. For the wells developed in long durations, the four-electrode EMF is limited because of the contamination, distortion, and corrosion of the oil tubing.

A Novel Approach to Extracting Casing Status Features Using Data Mining

Casing coupling location signals provided by the magnetic localizer in retractors are typically used to ascertain the position of casing couplings in horizontal wells. However, the casing coupling location signal is usually submerged in noise, which will result in the failure of casing coupling detection under the harsh logging environment conditions. The limitation of Shannon wavelet time entropy, in the feature extraction of casing status, is presented by analyzing its application mechanism, and a corresponding improved algorithm is subsequently proposed. On the basis of wavelet transform, two derivative algorithms, singular values decomposition and Tsallis entropy theory, are proposed and their physics meanings are researched. Meanwhile, a novel data mining approach to extract casing status features with Tsallis wavelet singularity entropy is put forward in this paper. The theoretical analysis and experiment results indicate that the proposed approach can not only extract the casing coupling features accurately, but also identify the characteristics of perforation and local corrosion in casings. The innovation of the paper is in the use of simple wavelet entropy algorithms to extract the complex nonlinear logging signal features of a horizontal well tractor.

Calibration of Mineralization Degree for Dynamic Pure-water Measurement in Horizontal Oil-water Two-phase Flow

Abstract In order to solve the problem of dynamic pure-water electrical conductivity measurement in the process of calculating water content of oil-water two-phase flow of production profile logging in horizontal wells, a six-group local-conductance probe (SGLCP) is proposed to measure dynamic pure-water electrical conductivity in horizontal oil-water two-phase flow. The structures of conductance sensors which include the SGLCP and ring-shaped conductance probe (RSCP) are analyzed by using the finite-element method (FEM). In the process of simulation, the electric field distribution generated by the SGLCP and RSCP are investigated, and the responses of the measuring electrodes are calculated under the different values of the water resistivity. The static experiments of the SGLCP and RSCP under different mineralization degrees in horizontal oil-water two-phase flow are carried out. Results of simulation and experiments demonstrate a nice linearity between the SGLCP and RSCP under different mineralization degrees. The SGLCP has also a good adaptability to stratified flow, stratified flow with mixing at the interface and dispersion of oil in water and water flow. The validity and feasibility of pure-water electrical conductivity measurement with the designed SGLCP under different mineralization degrees are verified by experimental results.

A new method of measuring the oil-air-water three-phase flow rate

Abstract Oil–air–water three-phase flow patterns in small-diameter vertical measurement channels are complex, making it difficult to establish techniques for interpretation of logging information. In this study, dynamic experiments involving oil–air–water three-phase flows were performed using a novel production logging tool that combined a petal-type turbine flowmeter, a conductance sensor, and an optical fiber sensor in a simulation well. Sensor response characteristics were researched, and a new method of measuring the oil–air–water three-phase flow rate was proposed. The measurement range and resolution of the gas flow rate were 3–20 and 1 m3/d, respectively, and the relative error range of gas flow rate interpretation was 5–10%. The measurement range and relative interpretation error range of the total liquid flow rate were 10–60 m3/d and 5–10%, respectively. The measurement range and resolution of the water cut were 50–100% and 2%, respectively. The absolute error range of interpretation of the water cut ranged from 3.2% to 5%. Currently, the technique is valid for laboratory use under ideal conditions.

Modeling and optimal design of fiber-optic probe for medium detection based on computer simulation

This paper conducted a deep study on the technique of fiber-optic probe (FOP). Firstly, the feasibility of FOP medium detection was analyzed by establishing a mathematic model. Secondly, in order to improve the sensitivity of FOP, the material, shape and angle of conic sensitive tip of FOP were optimally designed by analyzing simulation experiments. Besides for improving light transmitting efficiency of FOP, based on simulation experiments, the optimum structure was concluded by evaluating the performances of eight structures of the bundle coupling light path. Lastly, a sapphire-FOP was developed on the foundation of above optimizations, the sapphire-FOP has high sensitivity and compact size, meanwhile, the output response experiment of the sapphire-FOP in different media, the response characteristics experiments of the sapphire-FOP piercing a gas bubble, and the response characteristics experiments of detection multiple gas bubbles in water medium were carried out to identify the performance of the sapphire-FOP in gas resolution, anti-contamination and response sensitivity.