An Evolutionary Algorithm for Multi-criteria Resource Constrained Project Scheduling Problem based On PSO

AbstractThis paper is regarding the Particle Swarm Optimization (PSO)-based approach for the solution of the resource-constrained project scheduling problem with the purpose of minimizing cost. In order to evaluate the performance of the PSO based approach for the resource-constrained project scheduling problem, computational analyses are given. As per the results the application of PSO to project scheduling is achievable

Geothermal development in the Kilauea East Rift Zone--status of reserves assessment and injection strategy

This memo addresses some basic concerns regarding the status of reserves assessment and the development of an injection strategy for waste water and gases from any power plant to be developed within the Kilauea East Rift Zone (KERZ). It is generally agreed that a considerable amount of exploitable geothermal reserves exist in the KERZ and possibly in the other rift zones of the Big Island. For example, the Puna Geothermal Venture (PGV} has been able to convince sophisticated investors and major financial institutions that at least a 30 MW (gross) power plant could be supported for 30 years from the reserves within a 500-acre portion of their leasehold. In fact, the Scientific Observation Holes (SOH) program of the State of Hawaii has confirmed the existence of a much larger geothermal system within the KERZ than had been proven before by commercial developers

Analysis of Geothermal Well Logs

In the petroleum industry, well logging is a well developed discipline that has matured over a fifty-year period. Compared to this, geothermal well logging is a very new field of activity. The current practice is to use the same logging equipment and the same log interpretation techniques for geothermal wells as had been used for petroleum wells. However, this approach has proven either inadequate or ineffective in most geothermal areas. The problems here are of two types: (1) those associated with logging equipment and operation, and (2) those connected with log interpretation techniques. This paper focuses on the log interpretation aspects only. 6 refs

Geothermal power capacity from petroleum wells – Some case histories and assessment

ABSTRACT There are three types of petroleum wells potentially capable of supplying geothermal energy for electric power generation: (a) a producing oil or gas well with a water cut, (b) an oil or gas well abandoned because of a high water cut, and (c) a geopressured brine well with dissolved gas. This paper considers the basic technical and economic aspects of power generations from each of the three types of wells and presents case histories of estimating the available power capacity of a typical well (or a group of wells) in each of the above categories. We have conducted these assessments for commercial developers and operators. The power capacity of wells in the first category is determined primarily by the production rate and temperature of the produced water, ambient temperature, and conversion efficiency of the geothermal power plant. The factors that control the wellhead temperature of the produced fluid are: formation temperature, well depth, well diameter and production rate. Our assessment of some producing oil wells in the Middle East showed that in spite of an attractive formation temperature, the wellhead temperature of the produced water was too low compared to the ambient temperature to allow commercial generation of geothermal power. However, solar energy or the gas being flared in such a field could be used to boost the temperature of the produced water and increase the power capacity. The power capacity of an abandoned gas well depends on: (a) production rate and temperature of the produced water, (b) ambient temperature, (c) conversion efficiency of the geothermal power plant, (d) water salinity, (e) gas content in the produced fluid, (f) heating value of the gas, and (g) the characteristics of the equipment used to generate power from the produced gas. The production rates of water and gas from such a well depend on the hydraulic properties of the formation, gas content (dissolved as well as free) in the formation water, formation temperature and pressure, and well design. It is shown that the well's productivity could be substantially improved by working it over; both pumping and self-flowing the well are considered. A conceptual design of a hybrid system to produce power from both the produced gas and water is proposed. A case history of assessment of such a gas well from the U.S. Gulf Coast is presented in the paper; it is concluded that power generation from the well is technically feasible, and can be commercially acceptable. The possible approaches to improving the project economics are discussed. The power capacity of a geopressured well is determined by all of the factors considered above for an abandoned oil or gas well plus the amount of overpressure in the formation. A geopressured production well that supplied the U.S. Department of Energy's demonstration power project in Pleasant Bayou, Texas, in the late 1980's was re-assessed. The well is estimated to be capable of generating 3.9 MW of which 1.5 MW is from geothermal energy, 1.9 MW from the produced methane and 0.5 MW from kinetic energy of the produced fluid. Injection of the power plant waste fluid is an important issue in developing a geopressured project. For the example above, the net power available after deducting the parasitic power for injection is 3.1 MW. The economics of such a project is dependent on the market price of natural gas; if the gas price is high enough it would be more profitable to sell the produced gas rather than generating power from it. GEOTHERMAL POWER FROM CO-PRODUCED OIL & GAS FIELD WATERS Water produced along with the oil or gas from a petroleum well is separated and injected back. If this water has adequate temperature, it is possible to extract the geothermal energy in the produced water and generate electric power before injecting the water. No drilling cost would presumably be involved in such a power generation project from co-produced water from active oil or gas wells compared to a conventional geothermal project, where the drilling cost typically amounts to 30% to 40% of the total capital cost of a project. As such, the capital cost for a geothermal project from co-produced water can be significantly lower per kilowatt generation capacity than for a conventional geothermal project. The potential power capacity of an oil or gas well, or a group of wells, producing with a water-cut would be determined primarily by the following variables: a) water production rate from the well or a group of wells; b) temperature of the produced water at the collection point or the outlet of the storage tank; c) water salinity; d) ambient temperature at the site vis a vis the temperature of the water; and e) conversion efficiency of the power plant to be used

Determination of TDS in Geothermal Systems by Well-Log Analysis

An estimate of t h e chemistry of the fluid within a geothermal reservoir is required to establish the geological source and the possible environmental impact of the fluid as well as scaling and corrosion problems which might develop during production. While a detailed analysis of the chemical composition of a geothermal fluid can only be obtained from a water sample, an estimate of the total dissolved solids (TDS) in equivalent sodium chloride (NaCl) concentration can be obtained from well logs. TDS can also be useful in geological correlation between wells. TDS can be determined directly from a pulsed neutron log and a porosity log, (if the type of formation is known), or from the water resistivity, R{sub w}, and the temperature, T. Three approaches are used to find R{sub w}, and thus TDS. The first method uses a dual induction focused log and information from the log heading. Next, is found by employing an electrical log and a porosity log. The last approach utilizes the spontaneous potential log and header data. Examples are provided to illustrate the techniques described which utilize calculated values of R{sub w} to determine TDS