Channa, Zohaib (ADNOC Offshore) | Al Qubaisi, Salama (ADNOC Offshore) | Al-Neaimi, Ahmed Khaleefa (ADNOC Offshore) | Al-Romaithi, Faris Sultan (ADNOC Offshore) | Al Syari, Ahmed Mahfoudh (ADNOC Offshore) | Al-Shehhi, Omar Yousef (ADNOC Offshore) | Nofal, Salman (ADNOC Offshore) | Khemissa, Hocine (ADNOC Offshore) | Akram, Fazeel Ahmad (ADNOC Offshore) | Al Feky, Mohamed (ADNOC Offshore) | El-Sheikh, Hosny (ADNOC Offshore)
The aim of this paper is to share a successful case study of implementing the GLDA acid in two case study wells, which helped in improving the well performance where conventional HCl acid was not effective.
Historically, the conventional HCl acid stimulation was performed on two case study wells, however, little to no improvement was observed after the acid job. The production history of both wells showed unstable behavior with load up tendency against the system pressure. Both wells frequently require unloading operation to put the well back online in case of any unforeseen platform shut down. In order to enhance the well performance and to sustain the productivity of the wells, an alternative acid called GLDA (Glutamic Diacetic Acid) stimulation was considered. GLDA is an environmentally friendly acid, biodegradable under water, non hazardous and can be handled and transported without special safety precautions. Unlike conventional HCl acid stimulation, GLDA acid is more expensive hence; a comprehensive process was adopted to ensure the proper candidate selection. For compatability study, the core samples from multiple reservoirs were tested with GLDA acid which showed positive results (creating deeper worm holes in all the cores provided), especially in the low permeable reservoirs. Fluid compatibility test of GLDA with crude oil was also found suitable without any asphaltenes precipitation & emulsion. Stimulation with GLDA acid was applied on both wells. Post job results proved significant enhancement in the production as well as production sustainability versus the conventional HCl acid stimulation.
It was recently detected that certain dense layers in the field are liable to hole collapse when in contact with acid during stimulation jobs hence resulting in hole plugging and therefore losing production / injection from the drain. This was further confirmed by experiments performed on different cores in the lab. A solution was looked into that a 4-1/2" liner "drop-off" to be run and set in the upper drain of the well where accessibility poses a concer. The 4-1/2" liner "drop-off" was executed in the well and proved to be very efficient.
Khemissa, Hocine (ADNOC offshore) | Channa, Zohaib (ADNOC offshore) | Nofal, Salman F. (ADNOC offshore) | McNeilly, Kevin Dean (ADNOC offshore) | AL-Felasi, Ali (ADNOC offshore) | Al-Mazrooqi, Laila Sayed (ADNOC offshore) | Al Qubaisi, Salama Darwish (ADNOC offshore) | Al-Shamsi, Latifa Ali (ADNOC offshore)
The company vision development plan to capitalize on oil production, sustainability, maximise recovery and as cost effective to reduce number of wells to be drilled requests to drill extended horizontal drains (Oil producer and water Injector).
Subsurface well location optimisation, focus in detail on targets location and the related risks. The present offshore case study, demonstrate furthermore how important to study in detail all hazards along the well path, such as lithology of side-track formation. The risk of well bore stability, collapse is very high in such formation. Subsequently, in case of collapse or drop of scratched portion of rocks, the horizontal drain will be plugged and cease to produce. This case study, demonstrate how this event happens and adequate solution was successfully applied.
To efficiently perform the proposed plan, and develop multilayer geological units with poor to moderate limestone, a detailed reservoir study was performed including all subsurface team and drilling division. It was proposed to drill and complete wells as extended horizontal drain (+3000 ft.), with several designs: multilateral drains or step down 6″open hole.
The first planned well was dual oil producer, two targets, one deviated and the second 6 inch horizontal 3000 ft. length. Feasibility with drilling engineer was performed to study all drilling parameters, drilling hazards, logging requirement, geosteering, equipment preparation and simulation for acid stimulation was showing easy to be executed with barge.
Channa, Zohaib (ADMA-OPCO) | Ahmad, Fazeel (ADMA-OPCO) | Khan, Muhammad Navaid (ADMA-OPCO) | Nofal, Salman. F. (ADMA-OPCO) | Al-Hosani, Ibrahim. A. (ADMA-OPCO) | Al-Shehi, Omar Y. S. (ADMA-OPCO) | Al-Neaimi, Ahmed K. (ADMA-OPCO)
The selection of optimum tubing size is one of the most critical steps in achieving the desired well productivity and prolonging the well life to maximize the hydrocarbon recovery; and it becomes more important for the naturally flowing well. It is a common industrial practice to reduce tubing size for extending the well life when a naturally flowing oil or gas well ceased to flow post experiencing the water breakthrough. Contrary to this general belief, an extensive piece of work has been carried to assess the well performance in high productivity (prolific) oil reservoir. In this paper, an actual case study is presented which demonstrates the overall better performance of a well completed with the bigger tubing size in a high productivity (prolific) oil reservoir. The study also compares the performance of the well completed in low productivity reservoir in the same field, which shows that the use of the bigger tubing size is a better option for sustaining the well life, hence negating the traditional industry belief of reducing the tubing size post water breakthrough into a well, regardless of the prevailing reservoir characteristics.
Khan, Muhammad Navaid (Abdalla Abed Abu Dhabi Marine Operating Company) | Al Neaimi, Ahmed (Abdalla Abed Abu Dhabi Marine Operating Company) | Al-Shehhi, Omar (Abdalla Abed Abu Dhabi Marine Operating Company) | Channa, Zohaib (Abdalla Abed Abu Dhabi Marine Operating Company) | Ahmed, Fazeel (Abdalla Abed Abu Dhabi Marine Operating Company) | Al Feky, Mohamed (Abdalla Abed Abu Dhabi Marine Operating Company) | Sarsekov, Arlen (Abdalla Abed Abu Dhabi Marine Operating Company)
Reservoir management has been defined in many different ways, such as, "a sequence of resource-deployment decisions made to maintain optimum economic recovery of petroleum", "the application of available technology and knowledge to a reservoir system in order to control operations and maximize economic recovery within given management environment", "rely on use of financial, technological, and human resources, while minimizing capital investments and operating expenses to maximize economic recovery of oil and gas from a reservoir" (Thakur 1996) etc. Overall, the whole purpose of reservoir management is to help oil companies make the best decisions to meet specific objective using all the available resources. Essentially a reservoir management & development strategy is comprised of various elements; however, the purpose of this work is to shed light at the key elements, which were recently revisited to tackle the evolving changes in reservoir conditions for a giant Abu Dhabi Field, with a development and production history of over 50 years. The intent on this paper is to share the unique methodology adopted to address the sector-based reservoir performance and to generate the relevant opportunities to tackle the pertaining issues.
Elfeky, Mohamed Helmy (Abu Dhabi Marine Operating Co.) | Al-Neaimi, Ahmed (Abu Dhabi Marine Operating Co.) | Yousef, Omar (Abu Dhabi Marine Operating Co.) | Al-Hosani, Ibrahim (Abu Dhabi Marine Operating Co.) | Iwama, Hiroki (Abu Dhabi Marine Operating Co.) | Farhan, Salman (Abu Dhabi Marine Operating Co.) | Seoud, Abouel (Abu Dhabi Marine Operating Co.) | Channa, Zohaib (Abu Dhabi Marine Operating Co.) | Khemissa, Hocine (Abu Dhabi Marine Operating Co.) | Khan, Muhammad Navaid (Abu Dhabi Marine Operating Co.)
Facing a well control issue while drilling multi reservoirs with different reservoir pressure is very common in oil field worldwide, each and every engineer who is involved in the operations is dealing with this issue on daily basis. However, if the unexpected high pressure is observed while drilling a matured reservoir with known pressure, it is always a challenge to identify the source of the problem and to define the efficient remedial action plan, without compromising the well deliverables. The case study presented in this paper is related to a workover of a well in a giant offshore field in Abu Dhabi, where abnormally high pressure encountered while drilling the reservoir section with little amount of flow into the wellbore. Identifying the source of discrepancy and to establish the mitigate plan without impacting Well's Workover/Drilling duration was a serious challenge. What made the situation more complicated was the high risk of water in the heel section of 6" horizontal drain, which was prone to shorten the well life significantly. This paper will introduce an efficient novel solution to use 4 ½" casing liner in a certain configuration, consisting of the mechanical and the Swellable packers to cure the cross communicating reservoirs (source of abnormal high pressure); and isolate the risky heel section of the well, to extend well life without impacting the planned well duration. This work will also describe the process of identifying the source of pressure, selecting the most suitable well completion strategy to meet the well objectives successfully. Moreover, it will also shed some light on the need of using reservoir simulation technique to assess different well completion options. Finally, the paper will be concluded with methodology on how to save time and cost whilst changing plans to cope with the unforeseen issues.
Ahmad, Fazeel (ADMA-OPCO) | Al-Neaimi, Ahmed Khalifa (ADMA-OPCO) | Saif, Omar Yousef (ADMA-OPCO) | Channa, Zohaib (ADMA-OPCO) | Iwama, Hiroki (ADMA-OPCO) | Sarsekov, Arlen (ADMA-OPCO) | El-Sayed, Hussein Saad (ADMA-OPCO) | Konopczynski, Michael (Tendeka) | Ismail, Ismarullizam Mohd (Tendeka) | Abazeed, Osama (Tendeka)
The gaint oilfield offshore Abu Dhabi was discovered in 1963 and came online in 1967. Horizontal drilling was introduced in 1989 to enhance recovery efficiency, leading to a large stock of horizontal wells to date. With the maturation and depletion of the field, areas of high, non-associated gas saturation have developed, and subsequent breakthrough to the horizontal production wells have resulted in high GOR that is above the shareholder's guideline. Many wells have been shut in due to high GOR.
Controlling uneven production and early gas breakthrough are the main challenges to achieving target production and maximum hydrocarbon recovery. Inflow control devices (ICDs) create additional pressure drop to balance the production flux, but cannot restrict unwanted effluents ‘gas/water’ once they break through.
The Autonomous Inflow Control Device (AICD) is an active flow control device that delivers a variable flow restriction in response to the properties (viscosity) of the fluid flowing through it. Gas flowing through the device is restricted more than oil. When used in an oil well segmented into multiple compartments, this design prevents excessive gas production when gas breakthrough occurs in one or more compartments.
An evaluation of remedial advanced completion methods was conducted to select the best method of recompleting the shut-in wells and restoring oil production while controlling gas breakthrough. The solution must not only control gas production from zones of the well with high gas saturation now, but must be able to react to future increase in gas saturation in other zones as depletion continues.
The "levitating disk" style AICD is ideally suited to this challenge, with the ability to greatly restrict the production from zones with high gas volume fractions. Modeling has indicated that total GOR can be reduced by 40% and total gas production reduced by over 60% compared to an open hole completion.
This paper illustrates how AICD technology can enable operators to re-activate wells shut-in due to high GOR. This paper also describes a systematic approach for modelling flow in horizontal wells with AICD's, and presents an evaluation comparing different completion technologies used to control excessive gas production and maximize oil recovery.
Channa, Zohaib (Abu Dhabi Marine Operating Co.) | Khan, Muhammad Navaid (Abu Dhabi Marine Operating Co.) | Iwama, Hiroki (Abu Dhabi Marine Operating Co.) | Husain, Ali (Abu Dhabi Marine Operating Co.) | Al-blooshi, Jamal R. (Abu Dhabi Marine Operating Co.) | El-Sayed, H. S. (Abu Dhabi Marine Operating Co.) | Nofal, Salman F. (Abu Dhabi Marine Operating Co.) | Al-feky, Mohamed H. (Abu Dhabi Marine Operating Co.) | Ahmed, Fazeel (Abu Dhabi Marine Operating Co.)
As a part of the effective reservoir management in commingled water injection wells crossing different formation layers with varying characteristics (Thickness, permeability, reservoir pressure etc), ICD completions in combination with open hole have successfully been deployed in ADMA-OPCO in more than 10 wells since 2009 to control water injection in high permeable formation and ensure uniform fluid sweep. ICDs were placed against high permeable formation for controlling injection rates while keeping open hole in lower permeable formation. Production logs (PLT) were run in most of the ICD deployed wells to quantify the injection rates across ICDs and open hole section. Based on production logging results, down-hole completion design changes were considered and incorporated in newer wells as a part of continuous improvement. Case histories of ICD installations across high permeable zones showed the technique helped in better injection distribution and reservoir performance improvement. The aim of this paper is to discuss the performance in water injectors with different ICD completion configurations, improvement in injection distribution in different permeability reservoirs, lesson learned during completion running operation.