Pilot wells

TFSA-WATERFLOOD PILOT. A 36 acre (1.14 x lO m2) TFSA-waterflood pilot was recently conducted in the Torrance Field in the Los Angeles Basin of Southern California. To characterize the fluid floi patterns within the pilot, an interwell chemical tracer study was conducted with sodium thiocyanate. Results of the tracer study are shown in Table IV. Only 61.6 % of the injected tracer was recovered in the produced fluids, indicating that as much as 38.4 % of the injected fluids were flowing out of the pattern. Furthermore, since only 1604 bbl/d (255 m3/d) of brine was injected into the pattern, as much as 75.9 % of the total fluids produced by pilot wells were from outside the pattern. 

Figure 3. Injection of TFSA significantly increased oil cut in fluids produced from pilot wells.

Incremental oil production for each of the pilot wells was calculated by subtracting the extrapolated production decline curve which was established prior to TFSA injection from the actual production after TFSA injection. Results of this analysis indicate that a total of 8150 + 850 bbl (1295 + 135 m3) of incremental oil were obtained due to injection of TFSA. 

The resnlts showed that continnous polymer injection will yield the higher recovery factor. The point at which the change to water occtrrs depends on the econorrrical evalrration. The forecasted primary recovery factor was 19% OOIP. By continnons injectiorr, the potymer displaced 66% of the oil in 30 years, bnt orrly half of this is expected to be produced in the fom pilot wells. Therefore, the incremerrtal recovery factor to be determined based on actrral prodnction is expected to be approximately 33%. 

Asahi Chemical Industry Company Ltd. was working to develop an adsorption process in the late 1970s and early 1980s that was to produce high purity EB as well as PX (100—103). In 1981 they reported that pilot plants results were being confirmed in larger equipment. However, this process does not appear to have been commercialized. 

The need for a pilot plant is a measure of the degree of uncertainty in developing a process from the research stage to a hiU commercial plant. A modification to a weU-known process may go directiy from basic research work to design of a commercial plant using this approach for a brand new process risks a significant failure. Hence, one or more intermediate size units are usually desirable to demonstrate process feasibiUty as well as to determine safe scale-up factors. 

Three types of computer control systems are commonly used for pilot-plant instmmentation. The first is a centralized system, usually based on a minicomputer or occasionally a mainframe. These systems have large storage capacities, substantial memories, and much associated equipment. They typically control all the pilot plants in an area or faciUty. Centralized systems are economical if a large number of units are involved but are becoming less common due to their high installation and maintenance costs as well as the limitation that any failure of the central system shuts down all pilot plants involved. 

The maintenance of analytical instmmentation requkes trained personnel and is a time-consuming task (39,40). An additional problem is the necessity of frequentiy checking the caUbration of the analysis instmmentation and recahbrating if requked. Stand-alone data gathering instmmentation, once common in pilot plants, has been vktuaHy replaced in all but the simplest pilot plants by a data gathering computer, usually used for process control as well. 

Pilot-plant start-up costs vary widely. The costs booked to the start-up as well as the extent of the commissioning activities labeled as "start-up" vary... 

In cases where a large reactor operates similarly to a CSTR, fluid dynamics sometimes can be estabflshed in a smaller reactor by external recycle of product. For example, the extent of soflds back-mixing and Hquid recirculation increases with reactor diameter in a gas—Hquid—soflds reactor. Consequently, if gas and Hquid velocities are maintained constant when scaling and the same space velocities are used, then the smaller pilot unit should be of the same overall height. The net result is that the large-diameter reactor is well mixed and no temperature gradients occur even with a highly exothermic reaction. 

The process monitors and controllers typically also have the capabiUty for data logging, analysis, and display. This capabiUty has made on-line control of pilot plants, as well as commercial-scale processes, desirable. Pilot-plant appHcations for on-line control have been described (106), and the use of such systems for both monitoring and process diagnosis has been discussed (107). A number of commercially available process control programs that mn on microprocessors have been reviewed (108). Virtually all of them incorporate graphic display as an integral part of the interactive capabiUty of the program. 

However, it is not always possible to run a pilot-plant test in order to determine the depth of cut. A well-accepted alternative approach makes use of the more sophisticated test leaf illustrated in Fig. 18-97. This test leaf is designed so that the cake and precoat are extruded axially out the open end of the leaf. The top of the retaining wall on this end of the leaf is a machined surface which serves as a support for a... 

Experimental analysis involves the use of thermal hazard analysis tests to verify the results of screening as well as to identify reaction rates and kinetics. The goal of this level of testing is to provide additional information by which the materials and processes may be characterized. The decision on the type of experimental analysis that should be undertaken is dependent on a number of factors, including perceived hazard, planned pilot plant scale, sample availability, regulations, equipment availability, etc. 

Product or Process Development—A company can develop a new product or process as a quasi-research effort with a toller while simultaneously building the in-house production capacity. This allows problems found in the toller s intermediate scale efforts to be fixed in the large-scale process and to reduce development time and costs. It may simply be a case of a company wanting to try new raw materials in a well-known process without disrupting existing production or establishing a pilot facility. Tollers can provide a way to achieve these activities in a parallel fashion. 

Thus, bench or pilot studies are necessary to avoid technology misapplication in the field. The loss of time in treatment or the requirement to provide additional treatment for the waste is very expensive. Therefore, the relatively small costs and time needed for these studies make them useful tools in treatment selection. Bench-scale treatability studies for demonstrated technologies can cost between 10,000- 50,000 and take up to 6 weeks. Demonstrated technologies are those for which the major design parameters and treatment efficiencies are well understood. Innovative (and some biological processes) will require substantially more time (4-16 weeks) and money ( 25,000-> 200,000). These are estimates, and actual time and costs are going to depend on what kind of technology is under consideration. 

No field tests or pilot applications of this process have been performed to date. The product does well in bench tests in which the polyethylene jacket remains intact. Destructive bench tests which grind the product (such as the EP Tox or TCLP) defeat the purpose of the encapsulating jacket. 

Filtration experiments are typically conducted in pilot scale equipment and generally tests are conducted either at constant pressure or constant rate to determine axo, as well as s and Rf, for a given sludge and filter medium. Such tests provide empirical information that will enable the time required tor the pressure drop to reach the desired level for a specified set of operating conditions to be determined. In the initial stages of filtration, the filter medium has no cake. Furthermore, Ap is not zero, but has a value that is a function of the resistance of the medium for a given flowrate. This initial condition can be stated as ... 

Pilot plant experiments represent an essential step in the investigation of a process toward formulating specifications for a commercial plant. A pilot plant uses the microkinetic data derived by laboratory tests and provides information about the macro kinetics of a process. Examples include the interaction of large conglomerates of molecules, macroscopic fluid elements, the effects of the macroscopic streams of materials and energy on the process, as well as the true residence time in the full-scale plant. 

Pilot plant experiments vary over a wide range, aeeounting for industrial eonstraints (e.g., duration of operation, eontrol parameters, equipment reliability, and impurities in the raw materials). Seale-up problems are investigated during pilot plant experiments. A pilot plant is an experimental rig, whieh displays the part of the operation that eorresponds to an industrial plant. It allows for simultaneous analysis of the physieal and ehemieal meehanisms. A pilot plant is indispensable for measuring the extent of the possible interaetions between these two types of meehanisms. It ean be small to minimize extraneous eosts sueh as the total operation eost as well as other eonstraints. 

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