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Electrical submersible pumps focuses on the standard ESP configuration. It has the pump, seal chamber section, and motor attached to the production tubing, in this order from top down. In some wellbore completions and unique ESP applications, the arrangement and configuration of the system is modified. For a bottom-intake design, the production fluid is drawn in the intake ports located at the very bottom of the ESP system and discharged out of ports located just below the connection to the seal-chamber section. Because the discharged production fluid cannot flow through the seal-chamber section and motor, it has to exit into the casing or liner annulus and flow past these units.
Tracers are used in well to well tests to gather data about the movement and saturation of fluids and hydrocarbons in the subsurface. Radioactive tracers can be used to gather data about water or gas. This article discusses some of the commonly used radioactive gas tracers. Several authors report the use of radioactive gas tracers in oilfield applications. The tracers most frequently applied have been tritiated methane, tritiated ethane, and 85Kr.
Completion systems are the components necessary to complete the well after it is drilled and prepare it for production. There are many completion options available to oil and gas producers. Many of the basic components appear similar to those used in the past, yet they have been vastly improved, and their performance has been optimized to suit numerous environments. There are several keys to designing a successful completion system and selecting components that are fit for purpose for both the downhole environment and application. Consideration must be given to the various modes under which the completion must operate and the effects any changes in temperature or differential pressure will have on the tubing string and packer.
The table also includes an indication of the primary uses and benefits, along with the cements that they can be used with. The primary effects of the cement admixtures on the physical properties of the cement, either as a slurry or set, are presented in Table 2. This is a quick reference, and individual additives in a given category may not agree in total with the effects as given. It is also typically defined for individual additives, the properties and effects of which can be modified when additive combinations are used.
The implications of these compositional effects are very dependent on the oil composition, the composition of the injected gas, and the surface facilities and pipelines available in a particular field situation. The injected gas/oil composition interactions can be categorized as either swelling effects (gas dissolving into the oil phase) or stripping effects (various components from the oil transferring to the gas phase). The most obvious compositional effect in the immiscible gas/oil displacement process is that, if the oil is not saturated with gas at the reservoir pressure or if the reservoir pressure is increased as a result of the gas injection, the volume of gas dissolved in the oil will increase until the oil is saturated at that pressure. At the same time and because of the increased volume of gas in solution in the oil, the oil formation volume factor (FVF) will increase. This phenomenon, commonly called swelling, can increase the efficiency of the gas/oil displacement process.
The Merriam-Webster Dictionary defines simulate as assuming the appearance of without the reality. Simulation of petroleum reservoir performance refers to the construction and operation of a model whose behavior assumes the appearance of actual reservoir behavior. The model itself is either physical (for example, a laboratory sandpack) or mathematical. A mathematical model is a set of equations that, subject to certain assumptions, describes the physical processes active in the reservoir. Although the model itself obviously lacks the reality of the reservoir, the behavior of a valid model simulates--assumes the appearance of--the actual reservoir. The purpose of simulation is estimation of field performance (e.g., oil recovery) under one or more producing schemes. Whereas the field can be produced only once, at considerable expense, a model can be produced or run many times at low expense over a short period of time. Observation of model results that represent different producing ...
Reservoir simulation is a widely used tool for making decisions on the development of new fields, the location of infill wells, and the implementation of enhanced recovery projects. It is the focal point of an integrated effort of geosciences, petrophysics, reservoir, production and facilities engineering, computer science, and economics. Geoscientists using seismic, well-log, outcrop analog data and mathematical models are able to develop geological models containing millions of cells. These models characterize complex geological features including faults, pinchouts, shales, and channels. Simulation of the reservoir at the fine geologic scale, however, is usually not undertaken except in limited cases.
The Empire Abo field, located in New Mexico, US, covers 11,000 acres (12.5 miles long by 1.5 miles wide) and contains approximately 380 million stock tank barrels (STB) of original oil in place (OOIP). This reservoir is a dolomitized reef structure (Figure 1) with a dip angle of 10 to 20 from the crest toward the fore reef. The oil column is approximately 900 ft thick, but the average net pay is only 151 ft thick. The pore system of this reservoir is a network of vugs, fractures, and fissures because the primary pore system has been so altered by dolomitization; the average log-calculated porosity was 6.4% BV. Numerical simulations of field performance and routine core analysis data have indicated that the horizontal and vertical permeabilities are about equal.
Currently, the three major applications of conformance improvement oilfield foams are as a mobility control agent during steamflooding, a mobility-control agent during CO2 flooding, and gas blocking/plugging agents placed around production wells, often applied in conjunction with a gas flooding project. Although the use of foams for oil-recovery applications has been actively considered and studied for more than forty years, widespread application of foams for improving oil recovery has not occurred to date. In the pioneering work of the late 1950s and through the early 1970s, foam was identified to be a promising candidate for improving mobility control and sweep efficiency of oil-recovery drive fluids, especially gas-drive fluids. These early workers also noted that oil in porous media often tends to destabilize most aqueous foams and tends to harm oilfield foam performance. A number of the earliest oil industry proponents of the use of foam hoped that foams would eventually lead to routine "air flooding" of reservoirs.