Model Study of Foam as a Sealant for Leaks in Gas Storage Reservoirs

1970 ◽  
Vol 10 (01) ◽  
pp. 9-16 ◽  
Author(s):  
George G. Bernard ◽  
L.W. Holm
Keyword(s):  
Gas Flow ◽  
Pore Space ◽  
Economic Loss ◽  
Gas Storage ◽  
Flow In Porous Media ◽  
Underground Gas Storage ◽  
Foaming Agents ◽  
Storage Reservoir ◽  
Gas Leakage ◽  
Storage Reservoirs

Abstract Previous studies have shown that foam, because of its unique structure, reduces gas flow in porous media. This blocking action of foam appears to be especially suitable for sealing leaks in underground gas storage reservoirs. Such reservoirs often have permeable areas in the overlying caprock that allow permeable areas in the overlying caprock that allow vertical migration of gas from the storage zone to the upper formations. The escaped gas represents both a safety hazard and an economic loss. Our objectives in this study were to evaluate the effectiveness of foam in preventing the escape of gas from a leaky gas storage reservoir and to find the foaming agents that were most suitable for this purpose. We simulated the behavior of a leaky gas reservoir with a sandstone model and found that foam was 99-percent effective in reducing leakage of gas through the model. The amount of foaming agent required to seal a leak depends on the adsorption-desorption properties of the agent. After testing many foaming agents, we concluded that best results are obtained with certain modified anionic esters of relatively low molecular weight. Less than 0.3 lb of such agents is required per barrel of pore space in Berea sandstone. This study indicates that foam generation should be an effective and economical method for reducing or stopping gas leakage from an underground storage reservoir. Introduction The practicality of underground gas storage is greatly dependent upon the confinement that the caprock provides for the formation to be used as a storage reservoir. In spite of numerous precautions, several gas storage projects are plagued by vertical migration of gas from the intended storage zone to upper formations. Such gas leaks pose a safety hazard and represent an economic loss. If leakage is very high, the storage operation may be uneconomical. In at least one cases the leak problem is minimized by periodically collecting the escaped gas from the upper formation and reinjecting it into the storage reservoir. While such a solution is feasible, it is economically unattractive because the leak limits pressures and gas injection rates. Furthermore, energy must be expended in order to circulate the escaped gas. Recent studies have shown that foam, because of its unique structure, reduces gas flow in porous media. This blocking action of foam appears to be uniquely suitable for sealing leaks in underground gas storage reservoirs. Our objectives in this study were to determine the effectiveness of foam in reducing gas flow in a model of a "leaky" gas storage reservoir and to find foaming agents most suitable for this purpose. APPARATUS AND PROCEDURE PREPARATION OF THE MODEL PREPARATION OF THE MODELA laboratory model representing an estimated area of gas leakage in an Illinois gas storage reservoir was constructed of 24-in. × 6-in. × 1-in. Berea sandstone (See Fig. 1). The model was coated with Hysol plastic. The model represented an area of the reservoir approximately 600 ft wide, 2,400 ft long and 100 ft thick. The section contained about 2,000,000 bbl of pore space. The major portion of the reservoir is upstream of the inlet to this estimated area of leakage. The model, then, was geometrically scaled to this area of leakage in the reservoir. Distribution channels were installed on both ends of the model to permit linear gas flow through its entire width and thickness. Three injection wells were drilled into the model about one-third the distance from the inlet to the outlet. SPEJ P. 9

Foams as Blocking Agents in Porous Media

1970 ◽  
Vol 10 (01) ◽  
pp. 51-55 ◽  
Author(s):  
Robert A. Albrecht ◽  
Sullivan S. Marsden
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Natural Gas ◽  
Gas Flow ◽  
Gas Storage ◽  
Flow In Porous Media ◽  
Porous Rocks ◽  
Experimental Conditions ◽  
Storage Reservoirs

Abstract Although foam usually will flow in porous media, under certain controllable conditions it can also be used to block the flow of gas, both in unconsolidated sand packs and in sandstones. After steady gas or foam flow has been established at a certain injection pressure pi, the pressure is decreased until flow pressure pi, the pressure is decreased until flow ceases at a certain blocking pressure pb. When flow is then reestablished at a second, higher pi, blocking can again occur at another pb that will usually be greater than the first pi. The relationship between pi and Pb depends on the type of porous medium and the foamer solution saturation in the porous medium. A process is suggested whereby porous medium. A process is suggested whereby this phenomenon might be used to impede or block leakage in natural gas storage projects. Introduction The practice of storing natural gas in underground porous rocks has developed rapidly, and it now is porous rocks has developed rapidly, and it now is the major way of meeting peak demands in urban areas of the U. S. Many of these storage projects have been plagued with gas leakage problems that have, in some cases, presented safety hazards and resulted in sizeable economic losses. Usually these leaks are due to such natural factors as faults and fractures, or to such engineering factors as poor cement jobs and wells that were improperly abandoned. For the latter, various remedies such as spot cementing have been tried but not always with great success. In recent years several research groups have been studying the flow properties of aqueous foams and their application to various petroleum engineering problems. Most of this work has been done under problems. Most of this work has been done under experimental conditions such that the foam would flow in either tubes or porous media. However, under some extreme or unusual experimental conditions, flow in porous media becomes very difficult or even impossible. This factor also has suggested m us as well as to others that foam can be used as a gas flow impeder or as a sealant for leaks in gas storage reservoirs. In such a process, the natural ability of porous media to process, the natural ability of porous media to generate foam would be utilized by injecting a slug of foamer solution and following this with gas to form the foam in situ. This paper presents preliminary results of a sandy on the blockage of gas flow by foam in porous media. It also describes how this approach might be applied to a field process for sealing leaks in natural gas storage reservoirs. Throughout this report, we use the term "foam" to describe any dispersed gas-liquid system in which the liquid is the continuous phase, and the gas is the discontinuous phase. APPARATUS AND PROCEDURE A schematic drawing of the apparatus is shown in Fig. 1. At least 50 PV of filtered, deaerated foamer solution were forced through the porous medium to achieve liquid saturation greater than 80 percent. Afterwards air at controlled pressures was passed into the porous medium in order to generate foam in situ. Table 1 shows the properties and dimensions of the several porous media that were used. The beach sands were washed, graded and packed into a vibrating lucite tube containing a constant liquid level to avoid Stoke's law segregation over most of the porous medium. JPT P. 51

A Method for Determining the Optimum Location of Wells in a Reservoir Using Mixed-Integer Programming

1974 ◽  
Vol 14 (01) ◽  
pp. 44-54 ◽  
Author(s):  
Gary W. Rosenwald ◽  
Don W. Green
Keyword(s):  
Mathematical Model ◽  
Gas Flow ◽  
Demand Curve ◽  
Gas Storage ◽  
Mixed Integer ◽  
Trial And Error ◽  
Flow Rates ◽  
Storage Reservoir ◽  
Reservoir Simulator ◽  
Production Demand

Abstract This paper presents a mathematical modeling procedure for determining the optimum locations of procedure for determining the optimum locations of wells in an underground reservoir. It is assumed that there is a specified production-demand vs time relationship for the reservoir under study. Several possible sites for new wells are also designated. possible sites for new wells are also designated. The well optimization technique will then select, from among those wellsites available, the locations of a specified number of wells and determine the proper sequencing of flow rates from Those wells so proper sequencing of flow rates from Those wells so that the difference between the production-demand curve and the flow curve actually attained is minimized. The method uses a branch-and-bound mixed-integer program (BBMIP) in conjunction with a mathematical reservoir model. The calculation with the BBMIP is dependent upon the application of superposition to the results from the mathematical reservoir model.This technique is applied to two different types of reservoirs. In the first, it is used for locating wells in a hypothetical groundwater system, which is described by a linear mathematical model. The second application of the method is to a nonlinear problem, a gas storage reservoir. A single-phase problem, a gas storage reservoir. A single-phase gas reservoir mathematical model is used for this purpose. Because of the nonlinearity of gas flow, purpose. Because of the nonlinearity of gas flow, superposition is not strictly applicable and the technique is only approximate. Introduction For many years, members of the petroleum industry and those concerned with groundwater hydrology have been developing mathematical reservoir modeling techniques. Through multiple runs of a reservoir simulator, various production schemes or development possibilities may be evaluated and their relative merits may be considered; i.e., reservoir simulators can be used to "optimize" reservoir development and production. Formal optimization techniques offer potential savings in the time and costs of making reservoir calculations compared with the generally used trial-and-error approach and, under proper conditions, can assure that the calculations will lead to a true optimum.This work is an extension of the application of models to the optimization of reservoir development. Given a reservoir, a designated production demand for the reservoir, and a number of possible sites for wells, the problem is to determine which of those sites would be the best locations for a specified number of new wells so that the production-demand curve is met as closely as possible. Normally, fewer wells are to be drilled than there are sites available. Thus, the question is, given n possible locations, at which of those locations should n wells be drilled, where n is less than n? A second problem, that of determining the optimum relative problem, that of determining the optimum relative flow rates of present and future wells is also considered. The problem is attacked through the simultaneous use of a reservoir simulator and a mixed-integer programming technique.There have been several reported studies concerned with be use of mathematical models to select new wells in gas storage or producing fields. Generally, the approach has been to use a trial-and-error method in which different well locations are assumed. A mathematical model is applied to simulate reservoir behavior under the different postulated conditions, and then the alternatives are postulated conditions, and then the alternatives are compared. Methods that evaluate every potential site have also been considered.Henderson et al. used a trial-and-error procedure with a mathematical model to locate new wells in an existing gas storage reservoir. At the same time they searched for the operational stratagem that would yield the desired withdrawal rates. In the reservoir that they studied, they found that the best results were obtained by locating new wells in the low-deliverability parts of the reservoir, attempting to maximize the distance between wells, and turning the wells on in groups, with the low-delivery wells turned on first.Coats suggested a multiple trial method for determining well locations for a producing field. SPEJ P. 44

High Operation Flexibility and Reliability by Multi-Unit Compressor Arrangement for Gas Storage Applications

1988 ◽  
Author(s):  
Harald Neuburg ◽  
Klaus D. Schmidt
Keyword(s):  
Gas Flow ◽  
Operating Experience ◽  
Gas Storage ◽  
Reservoir Engineering ◽  
Buffer Gas ◽  
Underground Gas Storage ◽  
Gas Compression ◽  
Gas Market ◽  
Operation Flexibility ◽  
Selection Of

The growing gas market and the increasing ratio of imported gas to gas produced within a country requires an expanded capacity for buffer gas storage to compensate for differences between constant import gas flow and seasonal variances in consumption. For economical operation of the gas storage facility and for moving extensive quantities of gas, high operating flexibility as well as high availability and reliability of gas compression equipment are required. This paper will report on an underground gas storage project and indicate specific objectives for the project in reservoir engineering, gas compression and free-flow withdrawal duties. It will also deal with the sizing and selection of gas turbine driven centrifugal compressor sets, including the required station equipment. Finally, operating experience will be discussed.

scholarly journals Monitoring and Balance of Gas Flow in Underground Gas Storage

2013 ◽  
Vol 6 ◽  
pp. 485-491 ◽  
Author(s):  
Roman Danel ◽  
Lukáš Otte ◽  
Vladislav Vancura ◽  
Michal Řepka
Keyword(s):  
Gas Flow ◽  
Gas Storage ◽  
Underground Gas Storage

scholarly journals Albertan Gas Storage Reservoirs: A New Direction for Royalty Administration

1993 ◽  
Vol 31 (1) ◽  
pp. 107
Author(s):  
Colin Q. Winter
Keyword(s):  
Government Policy ◽  
Gas Storage ◽  
Storage Reservoir ◽  
Energy Company ◽  
Storage Reservoirs ◽  
Insight Into

The Alberta Government and Alberta Energy Company Ltd. have entered into an Agreement for that company to own and operate, for itself and other Storers, an operationally fully diversified, gas storage reservoir at Suffield, Alberta. This Agreement circumvents the existing Alberta regulations and offers us an insight into current Alberta Government policy for Alberta Crown royalty obligations created by upstream storage in Alberta.

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