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...Fluid capacitance logging is used to distinguish the mix of water and hydrocarbons in the wellbore ...fluid. The ...fluid-capacitance-logging tool includes an inside dielectric probe located on the tool's axis. The probe is surrounded by an ...
Fluid capacitance logging is used to distinguish the mix of water and hydrocarbons in the wellbore fluid. The fluid-capacitance-logging tool includes an inside dielectric probe located on the tool's axis. The probe is surrounded by an outside housing that is open to the wellbore fluid. Together, the probe, the housing, and the fluid constitute an electrical capacitor, the capacitance level of which depends on the particular fluid, or fluids, within the capacitor. Circuitry within the tool is connected to the electrical capacitor, with the result that the circuitry generates an oscillating signal that varies inversely with the capacitance level.
...ation section of the tool ensures that the levels are perpendicular to true vertical. Twenty-eight capacitance sensors are deployed on "wings" from the tool in such a way that there are ...capacitance sensors spanning each of the eight levels. An array of ...capacitance sensors spans levels at a first position along the tool's axis. Another array of sensors spans leve...
Layered flow often occurs in high-angle wells (i.e., a water layer in the lower part of the wellbore cross-section, an oil layer above the water, and a gas layer at the upper part of the cross-section). While the tools used in vertical wells have proven effective in high-angle wells on most occasions, special tools have been developed for studying two- and three-phase flow. These tools make use of arms to position electrodes across the casing diameter. Consequently, they are "blind" to flow outside a screen or perforated liner. The brief descriptions of these tools that follow are based on the limited published information and personal discussions with suppliers.
... Edward D. Holstein, Editor Copyright 2007, Society of Petroleum Engineers Chapter 4 – Production Logging R.M. McKinley, SPE, Consultant and Norman Carlson, Consultant ISBN 978-1-55563-120-8 Get permissi...bles prepared for readers that are consulting this text to find out quickly what type of production-logging tools are appropriate to a particular problem. These tables indicate what tools to use, how to use ... by themselves. The indexing scheme used in the tabulation is explained in the Appendix. Production-logging tools find many applications from the time a well is drilled until abandonment and, occasionally, b...
The following sections describe operating principles for each of the tools listed in Table 4.1. The text will indicate applications for which a tool is best suited, those for which it is only partially suited and, when possible, those for which a tool is not suitable. Some interpretive principles and recommended logging procedures will be presented in examples. However, the reader should refer to the Appendix for detailed information of this type. Oxygen-activation, cement-bond, and casing-inspection tools are not treated. These tools are, however, included in the application tables of the Appendix.
...in many models of heating of reservoirs (it is strictly zero only for incompressible fluids.). The fluid flow equation in the porous media of the reservoir, deemed to be representative of solution-gas-dri...ent viscosity, k is the permeability, c is the compressibility, and Φ is the porosity. The fluid velocity, V (we assume that only oil is present) has the following components: ...(5) ...(6) The mass fluid flow per unit area, Q m, and the temperature-dependent kinematic viscosity, ν, are given by ...
In the modeling of any system, one is always faced with the dilemma of choosing the level of complexity that correctly predicts the response of interest. In the case of modeling the electrical heating of wells and reservoirs for heavy or extra-heavy oil at low frequencies (below the microwave range) and considering only one liquid phase and no gas phases, the systems of equations shown in this article are considered sufficient. The problem is still unsolved for the case of microwave heating of reservoirs, in which a complete model, which correctly takes into account the electric losses of a system of solid grains, liquids with dissolved gases and salts (with the corresponding complex geometrical, scaling, and electrochemical properties in the presence of electrical diffusion currents and space charges), is not yet available. For the case of concentrated heating (either resistive or inductive) and distributed heating in the reservoir and surrounding regions (at frequencies below the microwave range) or distributed heating in the metal elements (at any frequency) the equations given next (in a cylindrical coordinate system) are deemed sufficient. The third term on the left, the product of temperature multiplied by the divergence of the velocity, has been neglected in many models of heating of reservoirs (it is strictly zero only for incompressible fluids.).
...warm because warmer brine is being injected into a formation cooled by years of waterflooding. The fluid-capacitance log (Fig. 1b) (well flowing) responds to the deepest oil entry at Depth C on an up run. However, fo...uling of the capacitance probe by the heavy oil renders the remainder of the up run useless for detecting additional oil ent...elocity removed the heavy oil film; however, it again fouled upon exit from the tubing. The shut-in capacitance profile, recorded later, reveals an additional oil entry at Depth E. One usually depends on the re...
A suite of production logs can provide important information for fine-tuning tertiary recovery operations. Below the casing, oil is produced in the open hole under WAG (water-alternating-gas) recovery. The well produces 1381 RB/D of water, 119 RB/D of oil, and 245 RB/D of CO2. Carbon dioxide, CO2, dissolves primarily in the oil and secondarily in the water. The produced oil, with CO2 in solution, bubbles (or "percolates") up through the flowing water.
...pressure transducers available in the field, either individually or in combination, are mechanical, capacitance, strain gauge and quartz gauge. This article discusses how each of these types of pressure transduc...ctrum, for some very high-temperature applications, or as backup for an electronic pressure gauge. Capacitance transducers have a variable-gap capacitor in which the sensing element is formed by two metallic or...es. As the external pressure increases, the deflection of the sensing plate creates a change in the capacitance that can be mathematically related to the applied pressure. ...
This article discusses how each of these types of pressure transducers operate. In the Amerada gauge, a popular mechanical pressure transducer, the pressure-sensing element is a helical Bourdon tube. The tube is of sufficient length to rotate a clock-driven stylus a full circumference inside the cylindrical chart holder. The chart, usually made of coated metal, is recovered at the end of the test, unfolded until flat, and read on a high-precision optical machine. The transducer also incorporates a vapor-type recording thermometer to make temperature corrections on the pressure measurements.
...is commonly defined as electrical heating and the parameters used are voltage, current, resistance, capacitance, and inductance. The analysis of microwave heating processes requires the full description provided...ment of material, it dissipates electrical power in accordance with the value of the resistance and capacitance per unit volume of the different media. Sections of insulated tubing are required to direct most of...ency heating, which correctly includes the convective heat transfer but only considers one phase of fluid (incompressible oil) driven by a pressure source at the reservoir outer radius.  One year l...
Heating strongly affects the viscosity of the oil in the reservoir porous media and in the wells. The heating effect in the porous media of the reservoirs is simply represented by Darcy's law with a temperature-dependent viscosity, μ(T). The effect of the heating in a well (along the z direction), is represented by a temperature dependent viscosity used in the Hagen-Poiseville law. As in many other applications of electrical heating and in the case of well and reservoir heating, there is a wide range of available frequencies in the electrical spectrum, which can be used in diverse heating schemes. At the low-frequency (LF) end, energy is supplied directly from the 60 Hz distribution grid. Induction heating requires higher frequencies in the radio frequency (RF) range of 103 to 105 Hz, while heating is also possible at frequencies in the microwave (MW) range (MW 109 to 3 1010 Hz). Microwave heating has been widely used industrially in the past, but its application to reservoir heating is not widespread, although it has been receiving more attention lately. In this range of frequencies, the process is commonly defined as electrical heating and the parameters used are voltage, current, resistance, capacitance, and inductance.
...lve problems of reservoir engineering began around 1930. Initially, pressures were calculated using fluid levels; a later method was to inject gas into the tubing until the pressure became constant. The ea...rvoir, differential depletion of lithostatic layers with various permeabilities and the movement of fluid contacts can change the pressure profile. Monitoring the static pressures vs. time in developed res...d rapidly terminates away from the wellbore. Because the pressure wave is affected by the reservoir fluid transmissibility, kh/μ, higher transmissibility results in smaller pressure differentials and vice ...
The practice of using bottomhole pressure measurements to improve oil and gas production and solve problems of reservoir engineering began around 1930. Initially, pressures were calculated using fluid levels; a later method was to inject gas into the tubing until the pressure became constant. The earliest bottomhole pressure measurements were made with one-time-reading pressure bombs and maximum-indicating or maximum-recording pressure gauges that lacked the accuracy, reliability, or durability of present-day technology. The varied uses of bottomhole pressure and temperature measurements have increased in scope during the past two decades as instrumentation technologies have produced more reliable and accurate tools. These advances have made more applications possible, including use in multilayer reservoirs, horizontal wells, interference testing, and drawdown test interpretation. This chapter is focused mainly on the types of measurements made and the tools available. Some information is included on interpretation techniques to connect the data acquisition with its use in characterizing a reservoir and its contents. Detailed explanations of these interpretation techniques can be found in other chapters in this Handbook. Figure 1.1 – Pressure gradients in a well drilled in a virgin reservoir. In a developed reservoir, differential depletion of lithostatic layers with various permeabilities and the movement of fluid contacts can change the pressure profile. Monitoring the static pressures vs. time in developed reservoirs is a crucial tool for reservoir management. Pseudosteady-state flow behavior is observed when a well reaches stabilized production from a limited drainage volume. For constant-rate production under pseudosteady-state conditions, the difference between the flowing wellbore pressure and the average reservoir pressure in the drainage volume is constant, and the pressure drawdown is a linear function of time. The late-time buildup pressure will level off to the average reservoir pressure if the buildup duration is sufficiently long. Pressure depletion occurs with continued pseudosteady-state production. Transient flow is most often modeled with the radial diffusivity equation, which allows modeling pressure vs. time and pressure vs. distance from an observation point (typically, a well). At a sufficiently large time, the pressure disturbance anywhere in the reservoir is proportional to the logarithm of the inverse square of the radius away from the origin of the disturbance.