Well Design Specificities For Shallow Gas Production Of Tunu Field.

Author(s):  
Samir Oumer ◽  
Hafidh Taufiqurrachman ◽  
Marie-Pascale Perruchot ◽  
Fata Yunus
2021 ◽  
Author(s):  
Hajar Ali Abdulla Al Shehhi ◽  
Bondan Bernadi ◽  
Alia Belal Zuwaid Belal Al Shamsi ◽  
Shamma Jasem Al Hammadi ◽  
Fatima Omar Alawadhi ◽  
...  

Abstract Reservoir X is a marginal tight gas condensate reservoir located in Abu Dhabi with permeability of less than 0.05 mD. The field was conventionally developed with a few single horizontal wells, though sharp production decline was observed due to rapid pressure depletion. This study investigates the impact of converting the existing single horizontal wells into single long horizontal, dual laterals, triple laterals, fishbone design and hydraulic fracturing in improving well productivity. The existing wells design modifications were planned using a near reservoir simulator. The study evaluated the impact of length, trajectory, number of laterals and perforation intervals. For Single, dual, and triple lateral wells, additional simulation study with hydraulic fracturing was carried out. To evaluate and obtain effective comparisons, sector models with LGR was built to improve the simulation accuracy in areas near the wellbore. The study conducted a detailed investigation into the impact of various well designs on the well productivity. It was observed that maximizing the reservoir contact and targeting areas with high gas saturation led to significant increase in the well productivity. The simulation results revealed that longer laterals led to higher gas production rates. Dual lateral wells showed improved productivity when compared to single lateral wells. This incremental gain in the production was attributed to increased contact with the reservoir. The triple lateral well design yielded higher productivity compared to single and dual lateral wells. Hydraulic fracturing for single, dual, and triple lateral wells showed significant improvement in the gas production rates and reduced condensate banking near the wellbore. A detailed investigation into the fishbone design was carried out, this involved running sensitivity runs by varying the number of branches. Fishbone design showed considerable increment in production when compared to other well designs This paper demonstrates that increasing the reservoir contact and targeting specific areas of the reservoir with high gas saturation can lead to significant increase in the well productivity. The study also reveals that having longer and multiple laterals in the well leads to higher production rates. Hydraulic fracturing led to higher production gains. Fishbone well design with its multiple branches showed the most production again when compared to other well designs.


2016 ◽  
Vol 56 (1) ◽  
pp. 225 ◽  
Author(s):  
Kunakorn Pokalai ◽  
David Kulikowski ◽  
Raymond L. Johnson ◽  
Manouchehr Haghighi ◽  
Dennis Cooke

Hydraulic fracturing in tight gas reservoirs has been performed in the Cooper Basin for decades in reservoirs containing high stress and pre-existing natural fractures, especially near faults. The hydraulic fracture is affected by factors such as tortuosity, high entry pressures, and the rock fabric including natural fractures. These factors cause fracture plane rotation and complexities, leading to fracture disconnection or reduced proppant placement during the treatment. In this paper, rock properties are estimated for a targeted formation using well logs to create a geomechanical model. Natural fracture and stress azimuths within the interval were interpreted from borehole image logs. The image log interpretations inferred that fissures are oriented 30–60° relative to the maximum horizontal stress. Next, diagnostic fracture injection test (DFIT) data was used with the poro-elastic stress equations to predict tectonic strains. Finally, the geomechanical model was history-matched with a planar 3D hydraulic fracturing simulator, and gave more insight into fracture propagation in an environment of pre-existing natural fractures. The natural fracture azimuths and calibrated geomechanical model are input into a framework to evaluate varying scenarios that might result based on a vertical or inclined well design. A well design is proposed based on the natural fracture orientation relative to the hydraulic fracture that minimises complexity to optimise proppant placement. In addition, further models and diagnostics are proposed to aid predicting the hydraulically induced fracture geometry, its impact on gas production, and optimising wellbore trajectory to positively interact with pre-existing natural fractures.


2014 ◽  
Vol 508 ◽  
pp. 146-149
Author(s):  
Xiao Min Tang ◽  
Xin Deng ◽  
Jian Fu ◽  
Lin Hou

In this paper, based on log response in gas formation, effective identification curves for shallow gas reservoirs are preferred from casedhole compensated neutron log, neutron lifetime log and openhole logs, and 4 parameters and 5 overlap curves are developed for identification of shallow gas reservoirs in cased wells. A gas reservoir in cased wells is interpreted with proposed identification methods. The gas production testing results shows that the proposed methods can determine shallow gas reservoirs in cased wells accurately.


2021 ◽  
Author(s):  
Aaron C Hammer ◽  
Tom D Gonzalez ◽  
Herb P Dhuet ◽  
Hege Andresen ◽  
Siv Merete M Sunde ◽  
...  

Abstract The Troll Phase 3 (TP3) wells were designed to enable high gas rates and sand free production for an expected lifetime of 40 years with a minimum pressure drop. By taking reservoir and production properties into account, open-hole gravel pack (GP) sand screens in the lower completion and big bore tubing in the upper completion were selected. To further reduce the pressure loss in the well, reduce rig time and cost, and reduce deployment risks, eliminating the intermediate completion was proposed. Traditionally, an intermediate completion is required to serve as a gas-tight barrier for running of the upper completion, mainly due to historical limitations of the GP extension (GP sleeve) not being a barrier qualified to API 19AC Validation grade V0 (referred to as V0 hereafter) after pumping sand slurry through it (post-erosion). An extensive qualification program was completed to qualify the GP system to API 11D1 and API 19AC V0 for use as a gas-tight barrier post-erosion. This allows the GP system to serve as a primary barrier while installing the upper completion and temporarily abandoning the well. The GP packer was qualified to API 11D1 V0 with the additional requirement to perform entire qualification in as-rolled casing and including a plug-in-tailpipe load case. The GP sleeve provided the most technically challenging requirements: a full-scale erosion test, immediate closure of the sleeve after pumping operation, followed by API 19AC Annex A V0 validation. Challenges were encountered trying to meet the rigorous V0 (zero bubble) acceptance criteria post-erosion. A significantly different approach was developed to achieve gas-tight performance in debris-laden environments. The new design successfully passed the post-erosion API 19AC V0 qualification to the full rating of the GP sleeve. The GP system development and qualification enabled the industry-first V0 post-erosion GP system for Equinor, which eliminates the need for an intermediate completion. This state-of-the-art gravel pack system enabled the simplified high gas rate, big-bore well design, not previously possible given well barrier considerations. The reduced pressure drop across the lower completion is expected to yield a higher gas production rate for the 40 years expected well life, contributing significant value to the TP3 project.


2011 ◽  
Vol 14 (01) ◽  
pp. 76-112 ◽  
Author(s):  
G.J.. J. Moridis ◽  
T.S.. S. Collett ◽  
M.. Pooladi-Darvish ◽  
S.. Hancock ◽  
C.. Santamarina ◽  
...  

Summary The current paper complements the Moridis et al. (2009) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas-hydrate (GH) petroleum system; to discuss advances, requirements, and suggested practices in GH prospecting and GH deposit characterization; and to review the associated technical, economic, and environmental challenges and uncertainties, which include the following: accurate assessment of producible fractions of the GH resource; development of methods for identifying suitable production targets; sampling of hydrate-bearing sediments (HBS) and sample analysis; analysis and interpretation of geophysical surveys of GH reservoirs; well-testing methods; interpretation of well-testing results; geomechanical and reservoir/well stability concerns; well design, operation, and installation; field operations and extending production beyond sand-dominated GH reservoirs; monitoring production and geomechanical stability; laboratory investigations; fundamental knowledge of hydrate behavior; the economics of commercial gas production from hydrates; and associated environmental concerns.


Author(s):  
Pedro Vassalo Maia da Costa ◽  
Alvaro Maia da Costa ◽  
Julio Romano Meneghini ◽  
Kazuo Nishimoto ◽  
Gustavo Assi ◽  
...  

Abstract In 2006, giant oilfields were discovered in Brazil in a water depth of ∼ 2200 m and under a caprock of 2000 m of continues salt rock overlaying the reservoirs, called pre-salt. Currently more than a half of the Brazilian oil and gas production comes from these reservoirs. However, some of these assets have big Oil & Gas ratio with a high level of CO2 contamination, which are currently being reinjected in the reservoirs. This procedure gradually increases the CO2 content associated with the oil extracted, reducing well productivity and leading to high costs of CO2 and CH4 separation by the membrane technology. The Research Center for Gas Innovation (RCGI) located at the State University of São Paulo in Brasil, sponsored by Shell Brazil, is developing a technology that uses the thick layer of salt rock overlying the pre-salt reservoirs to build caverns where the contaminated gas will be injected and decontaminated. After 2 years of extensive research, several studies have been carried out to analyze the main critical aspects of the technology in order to evaluate its feasibility, and now it has been decided to advance to the field proof stage. The salt dome studied can accommodate the construction of 15 caverns, thus providing the confinement of approximately 108 million tons of CO2. Before the system be construct in full scale, it was decided to initially build an experimental cavern with smaller size to obtain field parameters of the final design of the caverns. This paper describes this development denominated Offshore Salt Cavern Ultra-deep Water CCS System, that aims to perform the natural gas storage, a natural gravitational separation between CO2 / CH4 inside the caverns, and the confinement of CO2 (CCS). It presents important results related to structural integrity analysis of the giant and experimental caverns, well design using the same methodology applied in more than 200 projects of the pre-salt oil wells, instrumentation plan of the experimental cavern, storage capacities and other relevant data. If the economics proves feasible, this offshore gas storage station will be the first of its kind and possibly the biggest CCS Project in the world.


2021 ◽  
Author(s):  
Mohammad Arif Khattak ◽  
Agung Arya Afrianto ◽  
Bipin Jain ◽  
Sami Rashdi ◽  
Wahshi Khalifa ◽  
...  

Abstract Portland cement is the most common cement used in oil and gas wells. However, when exposed to acid gases such as carbon dioxide (CO2) and hydrogen sulfide (H2S) under downhole wet conditions, it tends to degrade over a period of time. This paper describes the use of a proprietary novel CO2 and H2S resistant cement system to prevent degradation and provide assurance of long-term wellbore integrity. The CO2-resistant cement was selected for use in one of the fields in Sultanate of Oman after a well reported over 7% CO2 gas production resulting in well integrity failure using conventional cements. The challenge intensified when the well design was modified by combining last two sections into one long horizontal section extending up to 1,600 m. The new proposed cement system was successfully laboratory- tested in a vigorous CO2 environment for an extended period under bottomhole conditions. Besides selecting the appropriate chemistry, proper placement supported by advanced cement job simulation software is critical for achieving long-term zonal isolation. The well design called for a slim hole with 1,600 m of 4 ½-in liner in a 6-in horizontal section where equivalent circulating density (ECD) management was a major challenge. An advanced simulation software was used to optimize volumes, rheologies, pumping rates, and ECDs to achieve the desired top of cement. The study also considered a detailed torque and drag analysis in the horizontal section, and fit- for-purpose rotating-type centralizers were used to help achieve proper cement coverage. To date, this cement system has been pumped in 32 wells, including 24 with 6-in slimhole horizontal sections with no reported failures. The paper emphasizes the qualification and successful implementation of fit-for-purpose design of CO2- and H2S-resistant cement as well as optimized execution and placement procedures to achieve long-term zonal isolation and well integrity in a complex slimhole horizontal well design.


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