El objetivo del presente estudio fue determinar la diversidad planctónica existente en los diferentes cuerpos de agua de la Reserva Nacional Allpahuayo Mishana (RNAM), Loreto Perú. La investigación se realizó en 16 estaciones ubicadas en cuerpos de agua lóticos y lénticos. La colecta, identificación y análisis de comunidades biológicas fue realizada empleando la metodología del MINAM & UNMSM (2014) y se midieron los índices de Shannon – Weaver, Margaleff, Simpson y Pielou usando el programa PAST. Encontramos en la época húmeda 39 especies de fitoplancton cuyos taxa dominantes fueron Bacillariophyta, Charophyta, Chlorophyta y Euglenozoa, y en la época seca se identificaron 63 especies, cuyos taxa dominantes fueron Bacillariophyta, Charophyta, Chlorophyta y Cyanobacteria. Para el zooplancton en la época húmeda se identificaron 17 especies y en la época seca 24 especies y coincidentemente estuvieron dominadas por los taxones Rotatoria, Protozoa y Arthropoda. Los índices de Shannon – Weaver mostraron una biodiversidad media o normal; los de Margaleff que la diversidad estuvo relacionada con la riqueza y la abundancia de sus ambientes, los de Simpson que en general no hay dominio de una especie en particular, y los de Pielou que existen comunidades en equilibrio. Se concluye que las aguas de la cuenca media del río Nanay y la RNAM aún se conservan saludables, pese al impacto que se produce en su entorno.
One of the critical conditions in cementing operations of gas wells, is the underbalance that generates the entry of preflush in the annular space, especially with the use of in the fluid train, therefore, trying to ensure the pore Pressure control incorporating to the fluid system, only an extensive volume of Spacer. In this way a possible gas inflow is avoided that would lead to enormous economic losses, however in terms of a good removal, just having a spacer in the preflush system would only be Fulfilling a single function that is the drag of suspended solids. in the annular space without being able to disperse and reduce its solid structures. Our methodology has been proven in fields with high GOR and good petrophysical and reservoir conditions, which intend to add a volume of washes to the preflush system, thus Hydrostatic Balance with a low Rheological Spacer volume behind the mud. The preflush system is by batch and pumped at 4.0 bpm continuous, considering a volume of 20 barrel máximum to generate a contact time greater than five minutes, thus improving the conditions of removal, diluting, dispersing and moisturizing the wellbore and casing external. It evaluates Primary cement Using bond logs that was run three days after the cementing operation. The logging results indicate an average amplitude of around 5 mV, so the 5 ½" in. Casing cement job had 90% average bond index. Good zonal isolation was achieved. In addition, Mechanical factors such as reciprocating the casing once carried to Depth, and casing centralization with Standoff greater than 80%, guarantee zonal Isolation in the área of productive. The addition of a Surfactant to the formulation of the washes favors the water wettability of the wellbore in fron of cement. The use of surfactants in preflushes entrain invading gas downhole and créate a stable foam. This foam then presents significant resistance to flow, thereby limiting upward migration (Marrast et al, 1975). With regard to the properties of grouts dominate the rheologic behavior, with filtrations less than 50 cc /30 min, and compressive strength greater than 1,100 psi
In the Talara basin, the cementing of the production section represents a challenge to achieve effective zonal isolation around the pay zone and ensure an efficient hydrocarbon production. For this purpose, well cement design must be tailored to accomplish specific goals. Challenges related to depleted intercalation zones, gas-bearing formation, highly recycled drilling mud, and marginal economic incentives push operators to build a multidisciplinary team with cementing and drilling fluid service companies to optimize well cement design. The objective of this article is to present cementing lessons learned from a recent drilling campaign in the Peruvian northwest area. Cementing jobs in the Block IV of the Peruvian northwest area is usually complex due to poor zonal isolation according to cement bond evaluation tools (sonic logs). The lack of good cement quality is related to micro-channeling and loss of well integrity. In fact, things get more complicated due to the requirement of recycling of the drilling mud to cut costs. Highly recycled mud sticks to the formation walls, complicating its removal. Various measures have been taken to understand the issues behind poor cementing jobs. Proper cementing design and placement through continuous improvements in both drilling fluid and cement formulations resulted in successful cement placements with consistent outcomes in several wells. The formulation and designing of the pre-flushes, and the optimization of their rheological properties and wellbore exposure time, resulted in effective mud removal. For an 8.5 in hole, which was cased with a 5.5 in casing, the minimum wellbore exposure time of the pre-flush considered in the design was 2.5 minutes, each ending with a washer allowing the mud cake to disperse. Centralization was kept high with a standoff greater than 85%. The slurry design considered 14.7 ppg tail and 14.2 ppg lead slurries specifically tailored for the current conditions. Also, mechanical reciprocation of the casing string for about 10 ft-long strokes enabled more effective mud removal. Excellent results were obtained by the cement bond log based on the sonic principle. This log was taken 72 hours after the cementing job showed a 10 mV reduction in amplitude through the entire target zone, resulting in a 90% bonding index. The challenges related to the cementing complexities were finally overcome with a multidisciplinary team of engineers from both operating and service companies working together diligently. During this process, a low-cost and effective cementing job design was developed through continuous improvement. The design resulted in good repeatability and consistency in the cementing job.
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