This paper discusses the historical evolution and future performance of wellbore dynamics in a multilayered gas condensate well (100 MMSCFD) in the Camisea Field - Peru. The analysis included the modeling of water vapor content produced within the gas condensate stream and its multiphase behavior and interaction with other fluids inside the borehole through the reservoir depletion under commingled production. The goal of this study is to quantify the impact of the wellbore dynamics in well deliverability and the effective recovery of hydrocarbons for each individual layer, and propose actions to achieve an optimum production scheme.
The approach is based on the modeling and matching of dynamic behavior of the wellbore and individual layers with the observed data during 9 years. For this purpose a dynamic wellbore model was built using OLGA. The inputs to the model are: 1) the properties for each productive layer characterized using multirate test combined with PLT logs to get the individual IPR's; 2) the model of the reservoir fluid to properly represent the retrograde condensation and the behavior of water in the vapor phase; and 3) the liquid levels in the wellbore from historical PLTs and density logs.
In the field case studied, the analysis showed that the water vapor present in the fluid stream is a fundamental key to understand the evolution of fluid levels inside the wellbore. This is quite important since the water in the gas phase is not usually included in the EOS for reservoir simulation purposes and its impact in the wellbore dynamics is neglected because of the very low BSW (less than 1%). For the well that has been studied, the analysis revealed that the lower zone was prone to stop producing due to the higher productivity of the upper reservoirs. Consequently, the increase in liquid level was a result of the production decrease and not vice versa. After the lower layer stopped producing, it was observed that there was a quicker increase of the liquid column between the upper and lower reservoirs. This column was mostly condensate but it was gradually replaced by water in the liquid phase, which came from the vapor phase produced in the upper reservoirs. This slow replacement represents a more restrictive condition for the lower reservoir, as the column becomes denser.
This study allowed for the understanding the complex interaction between retrograde condensation and water vapor behavior with the wellbore dynamics. The study also describes the process of the liquid accumulation during the decline of production of multilayered reservoirs which was successfully matched with observed data. As a result of the analysis, a new completion scheme was proposed to effectively recover the hydrocarbons in the layers affected by liquid loading issues.
This seminar will teach participants how to identify, evaluate, and quantify risk and uncertainty in everyday oil and gas economic situations. It reviews the development of pragmatic tools, methods, and understandings for professionals that are applicable to companies of all sizes. The seminar also briefly reviews statistics, the relationship between risk and return, and hedging and future markets. Strategic thinking and planning are key elements in an organisation’s journey to maximise value to shareholders, customers, and employees. Through this workshop, attendees will go through the different processes involved in strategic planning including the elements of organisational SWOT, business scenario and options development, elaboration of strategic options and communication to stakeholders.
Decisions in E&P ventures are affected by Bias, Blindness, and Illusions (BBI) which permeate our analyses, interpretations and decisions. This one-day course examines the influence of these cognitive pitfalls and presents techniques that can be used to mitigate their impact. Bias refers to errors in thinking whereby interpretations and judgments are drawn in an illogical fashion. Blindness is the condition where we fail to see an unexpected event in plain sight. Illusions refer to misleading beliefs based on a false impression of reality.
Morales, Walter J. (National University of Engineering, Peru) | Porlles, Jerjes (University of Utah) | Rodríguez, Jose (National University of Engineering, Peru) | Taipe, Heraud (National University of Engineering, Peru) | Arguedas, Americo (National University of Engineering, Peru)
In addition, it is also noted that the Cretaceous seignions are wedged towards the high.
Mohamed, I. M. (Advantek Waste Management Services) | Algarhy, A. (Advantek Waste Management Services) | Abou-Sayed, O. (Advantek Waste Management Services) | Abou-Sayed, A. S. (Advantek Waste Management Services) | Elkatatny, S. M (KFUPM)
ABSTRACT: Slurry waste management may involve injection of solid-laden fluids with concentration up to 25%. To accomplish this without plugging the near wellbore pore space, a fracture is created first using a pad of clean fluid. In some cases, where the formation has a high permeability-thickness product, kh, high injection flow rate is needed to open up the fracture with clean fluids. Most disposal wells do not have large enough pumps to provide the needed flow rates. A combination of a lack of geomechanical understanding combined with poor injection or facility design leads some operators to create high formation damage around their wellbores in slurry injection applications by injecting slurry at flow rates which are insufficient to open fractures. Moreover, the damage causes injection pressure to build up rapidly, facilitating the creation of short fractures which tend to cause near wellbore stresses to increase more rapidly for a given amount of solid deposition than is the case with longer fractures. This paper presents one case study which evaluates the injection well using operational data.
Slurry injection emerged in the late 1980’s and is one of the major environmental and economic methods of waste disposal management (Abou-Sayed et al., 1989; Moschovidis et al., 1998). In slurry injection, solids are slurrified with suitable carrying fluid (e.g. fresh water, produced water, or sea water) (Willson et al., 1998; Moschovidis et al 1999). The slurrified wastes are then injected into an underground permeable formation (Marinello et al., 2010). To provide the maximum possible storage space for the wastes, a porous formation that meets specific criteria is hydraulically fractured (Abou-Sayed and Guo, 2001). One of these criteria is a sufficient permeability to allow the liquids to leak off into the formation through the fracture faces (Van den Hoek, 2002).
During water injection, hydraulic fractures might intentionally or unintentionally be created (Morales, et al, 1986). During matrix injection of water, the permeability of the near wellbore region might decline (formation damage) by the accumulation of the suspended solids in the injected water to form internal and external filter cake (Bennion et al., 1996). The formation damage accumulation will cause the injection pressure to increase (Abou-Sayed et al., 2007). Once the pressure increases to a point that exceeds the formation fracture pressure, a hydraulic fracture will be unintentionally created (Elkatatny et al., 2017). The created hydraulic fracture will enhance the well injectivity and a sudden drop in the injection pressure will be observed (Abou-Sayed and Zaki, 2005). Unlike water injection operations, creating a hydraulic fracture is essential for a successful slurry injection project (Abou-Sayed et al., 2002; Majidaie and Shadizadeh, 2009).
Pedroso, C. A. (Queiroz Galvão Exploração & Produção) | Salies, J. B. (Queiroz Galvão Exploração & Produção) | Holzberg, B. B. (Schlumberger) | Frydman, M. (Schlumberger) | Pastor, J. A. S. C. (Schlumberger)
Drilling horizontal wells in shallow and poorly consolidated reservoirs in deepwater scenarios involves risky operations due to the narrow mud weight window. Risks include severe drilling fluid losses, wellbore instability, and fault reactivation, which, in the worst case, may connect reservoir to the sea floor.
This work presents a case study of risk reduction based on geomechanics, which includes concepts of fault reactivation while drilling, permitted plastified area around the wellbore, and fit-for-purpose data acquisition, which allowed a recalibration of the model and timely changes on the drilling plan.
The study started with a full 3D geomechanical characterization, which is an advanced way to determine stress distribution in a field, in particular, along the faults. Based on this study, it was possible to locate and avoid zones of higher risks of losses and fault reactivation, mitigating drilling risks.
From the study, it was also possible to identify the main uncertainties of the model, which allowed a fit-for-purpose data acquisition plan. The most important missing information was a calibration point for the minimal horizontal stress in the reservoir. Previous drilling experience in the area and geomechanics modelling were not conclusive about losses mechanisms, and the upper limits for horizontal drilling were also not clear. In addition, borehole instability had been shown to be an issue on offset wells; therefore, lower limits for drilling were unclear too.
It was decided to drill a pilot hole down to the reservoir, set a packer in the caprock and perform a series of minifrac tests. The measured minimal horizontal stress in the reservoir was revealed to be lower than initially expected, which implied the need to recalibrate the model and make important adjustments to the drilling plan. The model was recalibrated and the safe mud weight window was found to be even narrower. It was identified that a lower and unprecedented mud weight had to be used in the horizontal section, which was an additional risk. To evaluate this risk, the concept of permitted plastified area around the wellbore was used, and a lower mud weight was selected under a risk analysis manner.
Based on the study, drilling risks were mitigated and horizontal drilling was performed successfully, with minimal losses and controlled wellbore collapse.
Neyra, O. (Repsol E&P) | Rojas, C. (Repsol E&P) | Caro, J. C. (Repsol E&P) | Rojas, F. (Schlumberger) | Vera, C. (Schlumberger) | Deplaude, O. (Schlumberger) | Borges, S. (Schlumberger) | Cortes, I. (Schlumberger) | Contreras, J. R. (Schlumberger) | Villar, V. (Schlumberger)
Drilling the reservoir section in the Sagari field (Peru) presents many challenges, such as wellbore collapsing in the extremely mechanically unstable Shinai formation; differential sticking in low-pressure, highpermeability sandstone reservoirs; and total losses due to the presence of natural fractures. This paper describes how the implementation of automated managed pressure drilling (MPD) and managed pressure cementing (MPC) techniques allowed overcoming those challenges in a remote location where logistics and equipment mobilization is an additional challenge. The preliminary geomechanical study indicated that an equivalent density (ED) of 10.5-lbm/gal was required to maintain wellbore stability, while 10.8-lbm/gal could not be exceeded due to the risk of differential sticking. Additionally, eliminating pressure variations in the mechanically unstable Shinai formation would prevent wellbore collapse. The MPD strategy for drilling the original 8.5-in hole section and sidetrack consisted in using an automated MPD System to maintain the ED profile within the 10.5 to 10.7-lbm/gal window along the open hole and a near-constant pressure of 10.5-lbm/gal in the most unstable Shinai formation at all times.
Ferretti, V. (Neoambiental) | Mange, G. (Neoambiental) | Aguerre, G. (Neoambiental) | Juarez, M. (Neoambiental) | Maffei, L. (Biodiversity Monitoring Program) | Gomez, F. (Biodiversity Monitoring Program) | Capello, N. (Pluspetrol) | Mendoza, E. (Pluspetrol)
This paper presents the results of a research conducted to assess the effects a 2D seismic survey may have had on medium and large mammals living in the Lower Urubamba basin (Cuzco, Peru), performed in the frame of the Camisea Project Biodiversity Monitoring Program (PMB). The research was conducted over an area of 900 ha, characterized by dense amazon rain forest and rich biodiversity, representing one of the 35 world biodiversity hotspots identified by Conservation International. Thirty four camera traps were installed along the seismic lines. Results yielded significant information regarding the effects diverse anthropogenic disturbances had on medium and large mammals in the course of the survey, concluding that, although some limited impact in time and space were identified, most of the species recorded remained in the surroundings, with little and only temporary drive away. In addition, the survey allowed the identification of 23 mammal species, many of them indicators of good conservation conditions.