Collaborative Approach Overcomes Cementing Challenges in Narrow Pressure Window Environment

2021 ◽  
Author(s):  
Denis Lobastov ◽  
Svetlana Nafikova ◽  
Ilshat Akhmetzianov ◽  
Shamil Zaripov ◽  
Dmitry Krivolapov
Keyword(s):  
Collaborative Approach ◽  
New Approach ◽  
Lost Circulation ◽  
Production Section ◽  
Managed Pressure Drilling ◽  
Friction Pressure ◽  
Zonal Isolation ◽  
Pumping Rates ◽  
Novel Strategy ◽  
Bottomhole Pressure

Abstract The collaborative approach used for cementing the production liner in an onshore development well in Russia is presented. The reservoir has a narrow window between pore and fracture pressures, which has previously caused formation instability and severe lost circulation issues during well construction, compromising zonal isolation objectives. Total loss of fluids experienced while cementing the 114.3 mm production liner in the first appraisal well in the field led to revising the cementing strategy. Collaboration among various parts of the drilling department and the opportunity to define a new approach resulted in a decision to introduce managed pressure drilling (MPD) to address the challenges associated with a narrow pressure window and uncertainty in pore pressure while drilling and cementing. This enabled implementing the optimal mud weight and adjusting equivalent circulating density (ECD) during cementing with minimum overbalance. Reducing the mud weight from 1.20 SG to 1.05 SG eliminated losses after running the liner and while cementing it. As a result, pre-job circulation rates and pumping rates during cementing could be increased, improving mud removal efficiency and achieving top of cement at the required depth. The constant-bottomhole-pressure mode of MPD was used to maintain the same ECD during displacement of the well to a lighter fluid and during cementing, avoiding well influx during pumpoff events by compensating for the annular friction pressure loss with surface backpressure. This first onshore managed pressure cementing operation executed within the same field in Russia (later named as field A) was completed flawlessly, with no safety or quality issues, zero nonproductive time, and achievement of the required zonal isolation across the challenging production section. The collaborative approach used was a novel strategy, with the mud weight program strategically adjusted before and during the cementing operation to achieve zonal isolation objectives.

Light Weight Cement Slurry Tailored With Suspended Beads For Optimum Isolation of Highly Depleted Reservoirs in Offshore Malaysia: A Case Study

2021 ◽  
Author(s):  
Mayank Patil ◽  
Ramesh Annamalai ◽  
Brendon Tan ◽  
Avinash Kishore Kumar ◽  
Chee Hen Lau ◽  
...  
Keyword(s):  
Light Weight ◽  
Cement Slurry ◽  
New Approach ◽  
Management Quality ◽  
Production Section ◽  
Zonal Isolation ◽  
Testing Techniques ◽  
Operational Issues ◽  
Batch Mixer

Abstract Hollow-glass microspheres (beads) are widely used to generate light weight cement slurries for cementing across highly depleted zones and weaker formations; this paper discusses tailoring of a cement slurry and the execution of cementing operations for the successful deployment of an innovative liquid bead solution instead of the conventionally blended beads to achieve zonal isolation for a development well in Malaysia. Usage of dry bulk blended beads poses many challenges, such as rig and vessel silo management, quality control of beads, multiple blends on the rig and excess back-up blends. A new approach has been proposed using a liquid bead system to produce a light weight cement slurry by adding beads stabilized within a suspension fluid as another liquid additive to help eliminate the need of dry bulk blending of beads and at the same time accomplishing all the obligatory cement properties for a production casing section in depleted zones. A successful offshore application of liquid beads was executed in a production casing, meeting all the necessary property requirements for cementing in a depleted zone. The cement slurry was developed in a local field laboratory with standard laboratory testing techniques and equipment. Liquid beads can be added to the cement slurry using liquid additive pumps or batch mixed on the surface. Considering the slurry volume of the production section and the importance of a homogeneous cement slurry, liquid beads were injected into the recirculating line of the cement batch mixer. A yard trial was performed prior to the actual job which validated the easy transfer of liquid beads. Relative to the conventional dry-blended approach, this economically more efficient liquid bead cement system was easy to mix and achieved the required design density without any operational issues. The cementing operation was executed with full returns throughout the job at maximum planned displacement rates. To evaluate cement placement, a post job analysis was performed. The first application of this liquid bead technology in Malaysia was to generate a light-weight cement slurry and was successfully implemented for a 9-5/8" production casing where 167 bbl of the liquid bead base cement slurry was mixed, pumped & effectively placed.

Geomechanics in Partnership – A Holistic Approach to Solving Drilling Challenges

2021 ◽  
Author(s):  
Mohammed Omer ◽  
Tosin Odunlami ◽  
Carlos Iturrious
Keyword(s):  
Middle East ◽  
Fractured Reservoirs ◽  
Holistic Approach ◽  
Wellbore Stability ◽  
Naturally Fractured Reservoirs ◽  
Skin Damage ◽  
Lost Circulation ◽  
Managed Pressure Drilling ◽  
Bottomhole Pressure

Abstract With rising energy demand, operators in the Middle East are now focusing on developing unconventional resources. To optimize hydraulic fracture stimulation, most of these deep gas wells are required to be drilled laterally and in the direction of the minimum horizontal stress. However, this poses an increased risk of stuck pipe due to hole instability, differential sticking and skin damage due to high overbalance pressures, which makes drilling these wells challenging and costly. Another major challenge in the Middle East is lost circulation due to natural fractures in carbonate reservoirs. Lost circulation currently accounts for loss of approximately $850-900 million USD per year globally across the industry (Marinescu 2014). This paper presents a case study where a holistic approach; combining geomechanics and drilling technologies were employed to address the drilling challenges specific to unconventional and naturally fractured reservoirs. Ultimately, this approach helped the client to mitigate stuck pipe issues, while proposing a physics/engineering-basedmethodology to reduce losses by sealing fractures, hence providing a roadmap to optimized drilling and mitigation of hazards with associated Non-Productive Time (NPT). The paper demonstrates a holistic approach, combining wellbore stability analysis, managed pressure drilling (MPD) and proposes a novel physics/engineering-based methodology for addressing lost circulation challenges. A 1-D wellbore stability model is initially developed to determine the safe operating downhole pressure limits and to effectively assess the drilling risks associated with the planned wellbore orientation. By accurately determining the required bottomhole pressure to prevent wellbore stability problems, managed pressure drilling technology can be implemented to provide improved drilling hazard mitigation by enabling reduced overbalance pressures, constant bottomhole pressure, and faster reaction time by instantaneously adjusting downhole pressures. A bi-particulate bio-degradable system is used as a lost circulation material (LCM). The bigger size cylindrical particles flowing at a pre-defined rate will form a bridge or a plug across the fracture aperture, providing mechanical stability and the smaller spherical particles will seal the gaps in the bridge there by providing an effective sealing of the fracture opening. From experience, implementing these methodologies and technologies in isolation has not provided satisfactory results. This indicates that a partnership which leverages the strengths of the individual disciplines from the early planning stages is necessary to effectively address the drilling challenges posed by unconventional and naturally fractured reservoirs. For the case study highlighted in this paper, the well was drilled to TD in a timely manner, while maintaining the integrity of the hole, hence confirming the viability of this approach. In addition, the physics and engineering design workflow for bi-particulate bio-degradable LCM demonstrates how it can be effectively deployed to mitigate lost circulation without skin damage to the formation

Successful Implementation of Managed Pressure Drilling and Managed Pressure Cementing Techniques in Fractured Carbonate Formation Prone to Total Lost Circulation in Far North Region

2021 ◽  
Author(s):  
Zhanna Kazakbayeva ◽  
Almas Kaidarov ◽  
Andrey Magda ◽  
Fuad Aliyev ◽  
Harshad Patil ◽  
...  
Keyword(s):  
Real Time ◽  
Successful Implementation ◽  
Integrity Test ◽  
Lost Circulation ◽  
Far North ◽  
Carbonate Formation ◽  
Managed Pressure Drilling ◽  
Geological Conditions ◽  
Minor Losses ◽  
Bottomhole Pressure

Abstract Drilling reservoir section in the oilfield located in Far North region is challenged with high risks of mud losses ranging from relatively minor losses to severe lost circulation. Numerous attempts to cure losses with traditional methods have been inefficient and unsuccessful. This paper describes implementation of Managed Pressure Drilling (MPD) and Managed Pressure Cementing (MPC) techniques to drill 6-1/8″ hole section, run and cement 5″ liner managing bottomhole pressure and overcoming wellbore construction challenges. Application of MPD technique enabled drilling 6-1/8″ hole section with statically underbalanced mud holding constant bottom hole pressure both in static and dynamic conditions. The drilling window uncertainty made it difficult to plan for the correct mud weight (MW) to drill the section. The MW and MPD design were chosen after risk assessment and based on the decisions from drilling operator. Coriolis flowmeter proved to be essential in deciphering minor losses and allowed quick response to changing conditions. Upon reaching target depth, the well was displaced to heavier mud in MPD mode prior to open hole logging and MPC. MPD techniques allowed the client to drill thru fractured formation without losses or gains in just a couple of days as compared to the months of drilling time the wells usually took to mitigate wellbore problems, such as total losses, kicks, differential sticking, etc. This job helped the client to save time and reduce well construction costs while optimizing drilling performance. Conventional cementing was not feasible in previous wells because of risks of losses, which were eliminated with MPC technique: bottomhole pressure (BHP) was kept below expected loss zones that provided necessary height of cement and a good barrier required to complete and produce the well. Successful zonal isolation applying MPC technique was confirmed by cement bond log and casing integrity test. Throughout the project, real-time data transmission was available to the client and engineering support team in town. This provided pro-active monitoring and real-time process optimization in response to wellbore changes. MPD techniques helped the client to drill the well in record time with the lowest possible mud weight consequently reducing mud requirements. The MPD system allowed obtaining pertinent reservoir data, such as pore pressure and fracture pressure gradients in uncertain geological conditions.

scholarly journals Drilling Fluid and Cement Slurry Design for Naturally Fractured Reservoirs

2021 ◽  
Vol 11 (2) ◽  
pp. 767
Author(s):  
Nediljka Gaurina-Međimurec ◽  
Borivoje Pašić ◽  
Petar Mijić ◽  
Igor Medved
Keyword(s):  
Drilling Fluid ◽  
Fractured Reservoirs ◽  
Naturally Fractured Reservoirs ◽  
Cement Slurry ◽  
Lost Circulation ◽  
Managed Pressure Drilling ◽  
The World ◽  
Naturally Fractured ◽  
Induced Fractures ◽  
Bottomhole Pressure

For years, drilling engineers have been faced with the challenge of drilling wells through naturally fractured reservoirs that are present around the world. During drilling, the pressure at the bottomhole of a well is frequently intentionally higher than formation pressure, which can result in the loss of mud in surrounding rocks. During well cementing, the bottomhole pressure is even higher than it is during drilling, because the cement slurry density is higher than the density of the mud. Therefore, if natural or induced fractures in the surrounding rocks are not plugged during drilling, the cement slurry can be lost to them, reducing their permeability which is undesirable in the case of a pay zone. To prevent the loss of circulation and the related consequences, it is necessary to apply good drilling and cementing practices and to use adequate methods and carefully selected materials for plugging the loss zones. The aim of this article is to give an overview of the preventive and corrective methods that can be applied in drilling and cementing through fractured zones as well as improvements in drilling and cementing technology to avoid lost circulation issues (e.g., aerated drilling fluid, casing while drilling, managed pressure drilling, expandable tubulars, lightweight cement slurries, etc.).

A new approach to the hydraulic fracture geometric dimensions determination

2017 ◽  
Vol 12 (1) ◽  
pp. 126-134
Author(s):  
A.M. Ilyasov
Keyword(s):  
Exact Solution ◽  
Hydraulic Fracture ◽  
Pressure Gauge ◽  
Hyperbolic Type ◽  
Fluid Injection ◽  
Fracturing Fluid ◽  
New Approach ◽  
Gauge Data ◽  
Bottomhole Pressure ◽  
Half Length

Based on the generalized Perkins-Kern-Nordgren model (PKN) for the development of a hyperbolic type vertical hydraulic fracture, an exact solution is obtained for the hydraulic fracture self-oscillations after terminating the fracturing fluid injection. These oscillations are excited by a rarefaction wave that occurs after the injection is stopped. The obtained solution was used to estimate the height, width and half-length of the hydraulic fracture at the time of stopping the hydraulic fracturing fluid injection based on the bottomhole pressure gauge data.

Technology Focus: Cementing and Zonal Isolation (May 2021)

2021 ◽  
Vol 73 (05) ◽  
pp. 65-65
Author(s):  
Gunnar DeBruijn
Keyword(s):  
National Laboratory ◽  
Self Healing ◽  
Evaluation Tool ◽  
Initial State ◽  
Los Alamos National Laboratory ◽  
Successful Case ◽  
Managed Pressure Drilling ◽  
Zonal Isolation ◽  
Primary Cementing ◽  
Technology Focus

Wow! What a year it has been! We have experienced enormous upheavals in our professional and social circles and wholescale changes in the way that we interact with each other. As engineers, though, we recognize that in every challenge there is an opportunity. I have been lucky to attend SPE online events, including a happy hour and a webinar on geothermal energy. As we witness a shift to renewable energy, I note that 2020 SPE President Shauna Noonan highlighted that our SPE professional expertise in the subsurface will be needed to both maintain existing energy production and develop new sources of energy. Cementing, zonal isolation, and well integrity continue to be an important piece of the puzzle. This year, in the presence of enormous challenges, the selected papers demonstrate step changes both in efficiency and in the results of cementing operations. Managed-pressure cementing extends the benefits of managed-pressure drilling, and a successful case is described in paper OTC 30481. Last year, we read about offline cementing in North America. Offline cementing continues to increase rig efficiency, and wellhead equipment that enables offline cementing is described in paper SPE 202439. Improving cementing results by enabling casing rotation with rotating cement heads is discussed in paper SPE 198970. Research that will enable future successful changes also continues. Although not summarized in this edition, extra reading is recommended for interesting discussions on proving shale as a barrier (SPE 200755), cement properties and initial state of stress in confined pressure conditions (SPE 201770), and the evaluation of neutron logging as a possible cement evaluation tool (SPE 202973). As an industry, we also continue to investigate materials that will provide effective isolation in the annulus. Papers about self-healing systems (SPE 203174), epoxy (SPE 202648), and expanding metal sealing systems (SPE 203354) are also recommended as extra reading. Although it has been a challenging year, operational improvements, research, and material investigation continue to provide engineering opportunities in cementing and zonal isolation. Recommended additional reading at OnePetro: www.onepetro.org. SPE 200755 - Innovative One-Trip System Helps Qualify Creeping Shale as Permanent Barrier for Plug and Abandonment of Wells on the Gyda Field by Thore Andre Stokkeland, Archer, et al. SPE 201770 - Laboratory Measurement of Cement Stress Before, During, and After Curing Under Undrained Condition With Constant Hydrostatic Pressure by Meng Meng, Los Alamos National Laboratory, et al. SPE 202973 - Potential Usage of Neutron Logging Technology for Casing Cement Evaluation—Feasibility Study by Espen Dommersnes, University of Stavanger, et al. SPE 203174 - A Game-Changing Technology for Cementing in Highly Deviated and Horizontal Wells Using Interactive Mud-Sealing Cement System by Choosak Orprasert, Mubadala Petroleum, et al. SPE 202648 - Primary Cementing Using Epoxy Resins as Additive: Experimental and Application by Khawlah Abdulaziz Alanqari, Saudi Aramco, et al.

Implementation of Factory Cementing Concept in the High-Intensity Drilling Environment of Khazzan, Sultanate of Oman

2021 ◽  
Author(s):  
Emmanuel Therond ◽  
Yaseen Najwani ◽  
Mohamed Al Alawi ◽  
Muneer Hamood Al Noumani ◽  
Yaqdhan Khalfan Al Rawahi ◽  
...  
Keyword(s):  
Shallow Water ◽  
High Intensity ◽  
Sultanate Of Oman ◽  
Cement Slurry ◽  
Short Term ◽  
Lost Circulation ◽  
Well Integrity ◽  
Sustained Casing Pressure ◽  
Zonal Isolation ◽  
Casing Pressure

Abstract The Khazzan and Ghazeer gas fields in the Sultanate of Oman are projected to deliver production of gas and condensate for decades to come. Over the life of the project, around 300 wells will be drilled, with a target drilling and completion time of 42 days for a vertical well. The high intensity of the well construction requires a standardized and robust approach for well cementing to deliver high-quality well integrity and zonal isolation. The wells are designed with a surface casing, an intermediate casing, a production casing or production liner, and a cemented completion. Most sections are challenging in terms of zonal isolation. The surface casing is set across a shallow-water carbonate formation, prone to lost circulation and shallow water flow. The production casing or production liner is set across fractured limestones and gas-bearing zones that can cause A- and B-Annulus sustained casing pressure if not properly isolated. The cemented completion is set across a high-temperature sandstone reservoir with depletion and the cement sheath is subjected to very high pressure and temperature variations during the fracturing treatment. A standardized cement blend is implemented for the entire field from the top section down to the reservoir. This blend works over a wide slurry density and temperature range, has expanding properties, and can sustain the high temperature of the reservoir section. For all wells, the shallow-water flow zone on the surface casing is isolated by a conventional 11.9 ppg lightweight lead slurry, capped with a reactive sodium silicate gel, and a 15.8 ppg cement slurry pumped through a system of one-inch flexible pipes inserted in the casing/conductor annulus. The long intermediate casing is cemented in one stage using a conventional lightweight slurry containing a high-performance lost circulation material to seal the carbonate microfractures. The excess cement volume is based on loss volume calculated from a lift pressure analysis. The cemented completion uses a conventional 13.7 - 14.5 ppg cement slurry; the cement is pre-stressed in situ with an expanding agent to prevent cement failure when fracturing the tight sandstone reservoir with high-pressure treatment. Zonal isolation success in a high-intensity drilling environment is assessed through key performance zonal isolation indicators. Short-term zonal isolation indicators are systematically used to evaluate cement barrier placement before proceeding with installing the next casing string. Long-term zonal isolation indicators are used to evaluate well integrity over the life of the field. A-Annulus and B-Annulus well pressures are monitored through a network of sensors transmitting data in real time. Since the standardization of cementing practices in the Khazzan field short-term job objectives met have increased from 76% to 92 % and the wells with sustained casing pressure have decreased from 22 % to 0%.

Obtaining Zonal Isolation in Geothermal Wells

2021 ◽  
Author(s):  
Allam Putra Rachimillah ◽  
Cinto Azwar ◽  
Ambuj Johri ◽  
Ahmed Osman ◽  
Eric Tanoto
Keyword(s):  
Best Practices ◽  
Oil And Gas ◽  
Lessons Learned ◽  
Free Fluid ◽  
High Heating Rate ◽  
Lost Circulation ◽  
Geothermal Well ◽  
Geothermal Wells ◽  
Zonal Isolation ◽  
Primary Cementing

Abstract Cementing is one of the sequences in the drilling operations to isolate different geological zones and provide integrity for the life of the well. As compared with oil and gas wells, geothermal wells have unique challenges for cementing operations. Robust cementing design and appropriate best practices during the cementing operations are needed to achieve cementing objectives in geothermal wells. Primary cementing in geothermal wells generally relies on a few conventional methods: long string, liner-tieback, and two-stage methods. Each has challenges for primary cementing that will be analyzed, compared, and discussed in detail. Geothermal wells pose challenges of low fracture gradients and massive lost circulation due to numerous fractures, which often lead to a need for remedial cementing jobs such as squeeze cementing and lost circulation plugs. Special considerations for remedial cementing in geothermal wells are also discussed here. Primary cement design is critical to ensure long-term integrity of a geothermal well. The cement sheath must be able to withstand pressure and temperature cycles when steam is produced and resist corrosive reservoir fluids due to the presence of H2S and CO2. Any fluid trapped within the casing-casing annulus poses a risk of casing collapse due to expansion under high temperatures encountered during the production phase. With the high heating rate of the geothermal well, temperature prediction plays an important part in cement design. Free fluid sensitivity test and centralizer selection also play an important role in avoiding mud channeling as well as preventing the development of fluid pockets. Analysis and comparison of every method is described in detail to enable readers to choose the best approach. Massive lost circulation is very common in surface and intermediate sections of geothermal wells. On numerous occasions, treatment with conventional lost-circulation material (LCM) was unable to cure the losses, resulting in the placement of multiple cement plugs. An improved lost circulation plug design and execution method are introduced to control massive losses in a geothermal environment. In addition, the paper will present operational best practices and lessons learned from the authors’ experience with cementing in geothermal wells in Indonesia. Geothermal wells can be constructed in different ways by different operators. In light of this, an analysis of different cementing approaches has been conducted to ensure robust cement design and a fit-for-purpose cementing method. This paper will discuss the cementing design, equipment, recommendations, and best available practices for excellence in operational execution to achieve optimal long-life zonal isolation for a geothermal well.

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