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Abstract One of the challenges encountered in hydraulic fracturing of unconventional resources is casing deformation. Casing deformation statistics vary across different regions of the world, but it is estimated to affect 20-30% of horizontal wells in some areas of operations. The consequences of casing failures can be varied but, in many cases, it affects the well production, wellbore accessibility and in some rare instances presents a situation of well control and its associated risks. Incidentally, most literature on casing deformation pertains to "plug & perf" fracturing operations in cemented completions though pipe deformation is known to occur in multi-stage fracturing (MSF) sleeves type of openhole completions as well. Intuitively, the two failure mechanisms may appear similar instead they represent very diverse well conditions that lead to pipe deformation. Tubular damage during fracturing is not caused by a single, consistent reason. Multiple mechanisms may be responsible for casing deformation; formation rock properties, wellbore configuration, cyclic loads acting on the tubulars, tubular quality, cement bond, or simply some operational aspects during drilling and completion conducive to pipe deformation. Tubing stresses analysis of the lower completion and especially of the individual components of the openhole MSF completion is seldom done. A comprehensive study was initiated by first validating the key data and parameters, multi-arm caliper data in conjunction with downhole camera imaging, and review of the physical mill-out patterns of frac plugs (in cased hole completions) and ball-seats used in MSFs to understand the damage pattern. This work was supported by detailed geo-mechanical properties profiles, diagnostic injection tests analysis, and evaluation of casing integrity under anticipated fracture loads. One of the primary learnings from this study was that wellbore quality had a significant bearing on the post-frac wellbore integrity for both types of well completions. The study indicated that well profile, design, and tool placement in the well also had a strong influence on axial load distribution in open-hole multistage completions. The mode of failure in openhole multistage wells was different than those seen in cemented liners. These differences do not necessarily fall under the domain of formation movement experienced in geomechanically complex and tectonically active areas. Since reservoir uncertainties are a reality, a good wellbore quality cannot always be guaranteed. It becomes necessary to manage pipe deformation with mitigating practices. This paper provides practical solutions to pipe deformation in cemented and openhole completions. The operational workflows allow upfront assessment with analytical tools to model the stress loads. By understanding the primary factors that affect well integrity, the likelihood of casing failure can be predicted and avoided ahead of time, save fracturing costs across high-risk areas, and not jeopardize production from multimillion-dollar completions. Managing well integrity is essential for development of hydrocarbon resources while preserving the environment and assuring safety of personnel.
- Asia > Middle East (0.68)
- North America > United States > Texas > Harris County > Houston (0.28)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Vaca Muerta Shale Formation (0.99)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Loma Campana Field > Vaca Muerta Shale Formation (0.99)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Loma Campana Field > Lower Agrio Formation (0.99)
- (2 more...)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- (4 more...)
Abstract Multi-stage matrix acidizing is a common stimulation technique applied in low permeability carbonate reservoirs to increase hydrocarbon production. Frac balls are utilized to activate stimulation sleeves to achieve pin-point stimulation. Frac balls used during each stimulation stage also help in isolating the already stimulated lower zones. However, subsequent milling interventions are required after stimulation to remove conventional composite or steel frac balls. Utilization of dissolvable frac balls eliminate the need of milling interventions and allows an obstruction-free path to the produced fluids. An overview of acid-resistant dissolvable frac balls deployed in a multi-lateral offshore multi-stage stimulation (MSS) application in conjunction with acoustic sensors is presented in this paper. A tri-lateral offshore well was drilled and completed with stimulation sleeve completions to perform multi-stage acid stimulation. The lower completion consisting of open-hole swellable packers and stimulation sleeves was successfully deployed with a metal-to-metal seal expandable liner hanger. The stimulation sleeves were successfully shifted open by the dissolvable frac balls. An additional real-time confirmation of the stimulation sleeve opening event was recorded with an acoustic system for every acid stimulation stage. Acoustic sensors provide increased operational efficiency through real-time diagnostic of dissolvable frac balls as they reach their respective baffles. Prior to deployment, the dissolvable frac balls were tested in a laboratory at downhole conditions to ensure that self-dissolution requirements of the frac balls are fulfilled. The dissolvable frac balls were successfully deployed in the offshore tri-lateral well, achieving required zonal isolation and hydraulic pressure integrity during multi-stage acid stimulation. Acoustic sensors provided real-time detection of each stimulation sleeve shifting open once the dissolvable balls reached their respective baffles. After the successful acid stimulation treatments, the frac balls dissolved from downhole conditions alone, allowing the return of full well-bore access on the three laterals for production. The utilization of dissolvable frac balls eliminated the subsequent coiled tubing milling interventions required with conventional frac balls after the stimulation. Significant costs and rig time was saved with this technology optimizing the post-stimulation phase of this tri-lateral well while achieving complete stimulation objectives. The dissolvable frac balls have proven to be acid-resistant in nature, with a differential pressure rating of up to 8,000 psi and temperature rating of up to 300ยฐF. The paper presents the successful application of an acid-resistant dissolvable frac ball deployed in a challenging offshore environment. The dissolvable frac ball technology proved to be successful under these challenging environments, saving significant time and intervention costs. Additionally, the application of an acoustic sensors is also discussed, which allowed efficient completion design and seamless execution.
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- Well Completion > Completion Selection and Design > Completion equipment (1.00)
Advancing the Understanding of Openhole MultiStage Completion Systems in KhazzanโHydraulic Fracturing Execution and Analysis
Ishteiwy, O. A. (BP) | Casero, A.. (BP) | Al-Shueili, A.. (BP) | Turk, G.. (BP) | Roy, A.. (BP) | Al Manji, A.. (BP) | Dawson, W.. (BP) | White, D.. (BP) | Kurniadi, S. D. (Schlumberger)
Abstract The Khazzan development in the Sultanate of Oman operated by BP includes a multi-layered gas reservoir with stresses impacted by tectonic activity which has led to numerous challenges around multi-stage hydraulic fracturing of horizontal wells within the field. These wells were primarily focused on cased-cemented horizontal sections through the reservoir but a decision was taken in 2014 to trial openhole multistage (OHMS) completion systems to understand their applicability in this field and the potential advantages such systems could bring with respect to the challenges seen in the cased-cemented systems. Two such systems have been run to date in the Khazzan development. Significant consideration has been given during the planning phase to follow a systematic process of implementation to deliver an effective learning curve with clear understanding of the impact of design and execution changes between wells. This paper will describe the details, including completion and fracturing design, fracturing execution and surveillance, and post-fracturing clean up and production, of the second OHMS well in the Khazzan development. The second well has built on the success of the initial trial and the well has been designed to demonstrate the repeatability and the reliability of this completion type in Khazzan. It was also tailored to further the understanding of some key unknown or uncertain elements of the fracturing treatments following the analysis and interpretation of the first OHMS completion. Specific focus areas that will be addressed in this paper include the use of a hydraulically activated toe fracturing sleeve, the effect of a reduction of mechanical packer spacing on fracture staging performance and efficiency, ball drop efficiency, and overall fracture execution efficiency improvements. A comparison of the system's performance across different reservoir quality will be examined, with the second system having been deliberately deployed in relatively low reservoir quality rock. The impact of various degrees of over-flush and under-flush on the individual fracture stage production performance will be reviewed. This is an important consideration for more conventional Middle East reservoirs and is often perceived to be a barrier to the implementation of the highly efficient systems currently deployed by North America.
- North America > United States (1.00)
- Asia > Middle East > Oman (0.89)
- Asia > Middle East > Oman > Central Oman > Barik Formation (0.99)
- Asia > Middle East > Oman > Ad Dhahirah Governorate > Arabian Basin > Rub' al-Khali Basin > Block 61 EPSA > Block 61 > Khazzan-Makarem Field > Khazzan Field > Miqrat Formation (0.99)
- Asia > Middle East > Oman > Ad Dhahirah Governorate > Arabian Basin > Rub' al-Khali Basin > Block 61 EPSA > Block 61 > Khazzan-Makarem Field > Khazzan Field > Buah Formation (0.99)
- (7 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Well Completion > Hydraulic Fracturing > Multistage fracturing (1.00)
- Well Completion > Completion Selection and Design > Completion equipment (1.00)
Abstract This paper will cover the design and installation of BPโs first 15Kpsi Open Hole (OH) completion in the Sultanate of Oman in March 2016 and also the initial execution results of the stimulation treatments in July/August of the same year. This change to the current well design and execution strategy has become necessary due to variable cased hole horizontal well results and greater understanding of the challenges of delivering efficient and sustained gas production from the higher fracture gradient areas of the Barik reservoir. The Khazzan (Barik) development in the Sultanate of Oman operated by BP is a tight gas project, requiring hydraulic fracturing of tight gas resources. Tight gas production from the deep hot reservoirs in the Sultanate of Oman has historically concentrated on cased hole completions stimulated with large hydraulic fractures. The original Basis of Design for Khazzan for Full Field Development consisted of horizontal wells with multiple hydraulic fracturing stages performed within a Cased & Perforated 4-1/2โณ liner design. Challenges encountered with the CH approach have included the following: Tight pressure deployment/pumping window within the existing completion design, complicated by a wide variation in areal and vertical stress regime. Variability in the injection response, proppant placement and particularly the quality of the fracture/wellbore connection that would and has been achieved. Lack of predictability regarding post-frac production rate, due to a variation in fracture placement achieved due to above two reasons. In 2014 a decision was made to introduce some flexibility in evaluating suitable fracturing designs incorporating a number of Lower Completion (LC) styles, one of which was a horizontal open-hole completion. Optimizing stimulation performance by evaluating ball dropped activated systems and over-displacement was seen to have significant potential. A multi-disciplinary approach involving drilling, completion, stimulation, intervention and subsurface was performed to ensure Project value was maximized and the objectives delivered. This paper will cover how the pressure rating of the OH completion was designed to 15 kpsi, in excess of the existing CH pressure rating. This includes screening and evaluation of the available open-hole LC system design and operational characteristics suitable to deliver propped gel fractures in 6โณ OH for 1,000 m horizontal wells. Screening criteria included; system/equipment technology status, associated drilling requirements and design for "5-7/8โณ hole" cost and duration versus the existing 8-3/8โณ hole configuration and an ability to meet the well stimulation Statement of Requirements (e.g. fracture placement, zonal isolation). The final system design will be detailed including wellbore orientation and trajectory, hole and casing sizes, zonal access and isolation method(s) and hydraulic fracture parameters, including fracture spacing, geometry and treatment design. Operational results will be presented for well construction and stimulation phases. Well construction results will include drilling performance comparison, wellbore preparation for the completion installation, drill-in/completion fluid requirements and packer spacing/zone selection criteria. Stimulation execution results will include evaluation of execution versus design, comparison of stimulation results for ball drop stage results versus plug and perf results. Assessment of Radioactive (RA) tracer results and evidence for OH packer integrity will also be presented. Conclusions will include an initial comparison of the execution of the drilling, completion and stimulation phases and lessons learned on the success of the design versus the original objectives.
- Europe > United Kingdom > North Sea > Southern North Sea > Southern Gas Basin > Sole Pit Basin > Block 43/26 > Ravenspurn South Field > Rotliegend Formation (0.99)
- Europe > United Kingdom > North Sea > Southern North Sea > Southern Gas Basin > Sole Pit Basin > Block 42/30 > Ravenspurn South Field > Rotliegend Formation (0.99)
- Europe > United Kingdom > North Sea > Southern North Sea > Southern Gas Basin > Sole Pit Basin > Block 42/29 > Ravenspurn South Field > Rotliegend Formation (0.99)
- (16 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Drilling > Casing and Cementing > Casing design (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- (3 more...)
Engineering Approach to Achieve the First Successful Multistage Acid Frac of a Tight Oil Reservoir Producer in Saudi Arabia
Lucado, Jared (Halliburton Saudi Arabia) | Al-Hajri, Muhammad A (Saudi Aramco) | Al-Mutairi, Khaled Mouawad (Saudi Aramco) | Soriano, J Eduardo (Halliburton Saudi Arabia) | Said, Rifat (Saudi Aramco) | Pacheco, Eduardo (Halliburton Saudi Arabia) | Mubarak, Tariq A (Saudi Aramco) | Rafie, Majid (Saudi Aramco) | Nugraha, Ikhsan (Saudi Aramco)
In Saudi Arabia, conventional oil reservoirs have been treated using conventional stimulation methods. The challenge is that many of the formations now are tighter and require improved stimulation methods. Fracturing is a major topic discussed in the industry as of late and as such using it in this formation will serve as a trial to shift from conventional stimulation methods to fracturing when facing tighter formations. This particular acid frac was performed in a tight carbonate formation ranging in permeability from 1 - 2 md. The chosen well is a newly drilled tri-lateral producer completed with a multi-stage frac completion in the mother bore and will serve as a pilot well for this reservoir in the area. The acid frac was a seven stage completion utilizing hydraulic fracturing. Several methods using pressure and injection were used to determine reservoir fracturing response and petrophysical properties. This paper will discuss the first multi-stage acid frac performed in an oil producer in Saudi Arabia. It will examine the entire process of candidate assessment, job preparations, and execution. In addition, the paper will discuss challenges faced, solutions taken, and the post-decision results. The paper will show how an injectivity test performed pre- and post-frac was used as a benchmarking tool to analyze the effectiveness of the frac. Finally, we will discuss the flowback of the well, initial results, lessons learned, and optimization of future jobs.
- Geology > Geological Subdiscipline > Geomechanics (0.93)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.61)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Well Integrity > Zonal isolation (1.00)
- Well Completion > Hydraulic Fracturing > Multistage fracturing (1.00)
- (5 more...)