Water Injection

Primary sweep efficiency in carbonate reservoirs is low due to the low contribution of the matrix in production. Also, due to unfavourable mobility ratio, secondary recovery is not also effective. Hence, design and application of an effective enhanced oil recovery method is essential to improve recovery. Different methods such as water injection, gas injection, chemical injection, thermal, and a combination of these methods such as water alternating gas (WAG), simultaneous WAG (SWAG), selective simultaneous WAG (SSWAG), foam injection, and foam-assisted WAG (FAWAG) are applied to improve the recovery efficiency in naturally fractured reservoirs. In this paper, selection of the best EOR method and well pattern for a naturally fractured reservoir is studied to reach the highest net present value (NPV) and field oil recovery efficiency (FOE). Results showed that the FAWAG process in a five-spot well pattern with 22.7% oil recovery efficiency is the best technical and economical method. Reference to this paper should be made as follows: Bagrezaie, M.A. and Pourafshary, P. (2016) 'Screening and optimisation of water/foam/gas injection EOR scenarios in a fractured reservoir', Int.

The gas turbine is a continuous-flow engine which develops steady aerodynamics and flame kinetics during stationary operation. These favourable features limit the constraints placed on fuel properties as to the performance of combustion and provide a considerable margin for devising clean combustion designs. This is why gas turbines have by essence access to a broad range of primary energies. However,

Rahayu field was discovered in 1973 and it is a three-way closure anticline bounded by thrust fault bearing NW-SE at the west. The hanging wall is the only oil productive block with area coverage of 5x3 km and consists of 129 producers and 24 peripheral
injectors.

The main oil production comes from the Sierra group formation that consists of 3 main reservoirs, A, B and C. The A reservoir is subdivided into A1950 sand, A2020 sand, and A2050 sand. The B reservoir is subdivided into B2250 sand. The C reservoir is subdivided into C2420R, C2420S, C2420T, and C2420U. Those reservoirs are deposited in the Early Miocene age in an estuary environment setting. The reservoir depth ranges from 1900-2800 feet. Since 1997 enhanced waterflood method was started to improve oil recovery by converting producer well at the flank structure into injector wells. Those peripheral injectors surround the Rahayu field, even near the main thrust fault, in order to maintain reservoir pressure and also fluid displacement.

Rahayu field is considered as a matured waterflood field and it needs alignment between peripheral injector-to-producer to make sure that the water is injected to the right reservoir. The main concern for this study is for all injectors that located along the thrust fault boundary. The main focus of this study was to make a robust interpretation for thrust fault outline and the subsurface location of injector and producer well trajectory along the fault surface.

The decision-making process related to field development planning is very complex. It involves significant investment and it is necessary to account for a large number of geologic, economic, and technical parameters. Most of these parameters are uncertain and these uncertainties must be considered when evaluating the risks associated with the projects. An appropriate choice of production strategy will ensure proper reservoir performance, leading to a satisfactory recovery. Therefore, it is very important to develop methodologies:to improve the quality of the results; and,to accelerate the process. This paper introduces a new optimization procedure which is applied to the production strategy planning process. The procedure was developed for several types of reservoirs and includes producer and injector vertical wells. Furthermore, it uses reservoir simulations to provide reliable production/injection forecasts for the evaluation of an objective-function. The procedure was developed i...

Microbial control of biogenic production of hydrogen sulfide in oil fields was studied in a model system consisting of pure cultures of the nitrate-reducing, sulfide-oxidizing bacterium (NR-SOB) Thiomicrospira sp. strain CVO and the sulfate-reducing bacterium (SRB) Desulfovibrio sp. strain Lac6, as well as in microbial cultures enriched from produced water of a Canadian oil reservoir. The presence of nitrate at concentrations up to 20 mM had little effect on the rate of sulfate reduction by a pure culture of Lac6. Addition of CVO imposed a strong inhibition effect on production of sulfide. In the absence of added nitrate SRB we were able to overcome this effect after an extended lag phase. Simultaneous addition of CVO and nitrate stopped the production of H2S immediately. The concentration of sulfide decreased to a negligible level due to nitrate-dependent sulfide oxidation activity of CVO. This was not prevented by raising the concentration of Na-lactate, the electron donor for sulfate reduction. Similar results were obtained with enrichment cultures. Enrichments of produced water with sulfide and nitrate were dominated by CVO, whereas enrichments with sulfate and Na-lactate were dominated by SRB. Addition of an NR-SOB enrichment to an SRB enrichment inhibited the production of sulfide. Subsequent addition of sufficient nitrate caused the sulfide concentration to drop to zero. A similar response was seen in the presence of nitrate alone, although after a pronounced lag time, it was needed for emergence of a sizable CVO population. The results of the present study show that two mechanisms are involved in microbial control of biogenic sulfide production. First, addition of NR-SOB imposes an inhibition effect, possibly by increasing the environmental redox potential to levels which are inhibitory for SRB. Second, in the presence of sufficient nitrate, NR-SOB oxidize sulfide, leading to its complete removal from the environment. Successful microbial control of H2S in an oil reservoir is crucially dependent on the simultaneous presence of NR-SOB (either indigenous population or injected) and nitrate in the environment. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 424–434, 2001.

In internal combustion engines, the water injection, also known as an anti-detonant injection, is spraying water into the cylinder or incoming air-fuel mixture to cool the combustion chamber of the engine, allowing for greater compression ratios and eliminating the problem of engine knocking. This effectively reduces the air intake temperature in the combustion chamber. The reduction of the air intake temperature allows for higher ignition timing to be employed, which ultimately increases the power output of the engine. Depending on the engine, improvement in power and fuel efficiency can also be obtained by injecting water. Water injection may also reduce carbon monoxide emissions. The purpose of this experiment is to investigate the effect of water injection on the engine performance, exhaust gas temperature, and exhaust emission of the S.I. engine, water is injected in specific quantities with compressed air. Single cylinder, two-stroke, air-cooled, 100 cc petrol engines were used in this experiment. Obtained data will compare to calculate the performance of specific fuel consumption, which will get without a water supply to a petrol engine based on performance. The performance test is conducted to find out the fuel efficiency and is compared with conventional engine present also emission is to be carried out to find CO (carbon monoxide) emissions.

This paper examines the macroscopic consequences of wettability variations at the pore-scale. Important theoretical issues relating to distributed contact angles are examined and a process simulator capable of simulating the full flooding cycle characteristic of laboratory wettability tests is described. Simulations predict that final waterflood recoveries from weakly water-wet, or even weakly oil-wet, systems can often exceed those from strongly water-wet systems-even though initial imbibition rates may lead to the opposite conclusion. The underlying pore level physics has been explored by defining a capillarity surface which incorporates the combined effects of both contact angle and pore dimension during the imbibition process. Finally, a regime-based framework has been developed which can be used to reconcile apparently contradictory wettability experiments.

... displacing oil, this IW will also displace and mix with either the connate water (CW) in the mobileoil zone of ... A combined reservoir simulation and chemical precipitation model for in situ brine mixing in the context of oilfield scale (barite) formation ... (i) Firstly, field observations have ...