Managed-Pressure Cementing in HPHT Well with Very Narrow Operating Pressure Window

2021 ◽  
Author(s):  
David Salinas Sanchez ◽  
Mario Noguez Lugo ◽  
Oscar Zamora Torres ◽  
Cuauhtemoc Cruz Castillo ◽  
Moises Muñoz Rivera ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Stopping Time ◽  
Operating Pressure ◽  
Cement Slurry ◽  
Working Pressure ◽  
Lost Circulation ◽  
Main Challenge ◽  
Fiber Technology ◽  
Open Hole ◽  
Reverse Circulation

Abstract A 7-in. liner was successfully cemented in the south east region of Mexico at 7530 m MD despite significant pressure and temperature challenges. The entire 1,370-m, 8.5" open hole section needed cement coverage and isolation to test several intervals. The challenge of the ultranarrow working pressure window was overcome by using managed pressure cementing (MPC) along with lost circulation solutions for the cement slurry and spacer. Due to the narrow pressure window (0.05 g/cc density gradient), mud losses could not be avoided during the cementing job. To limit and manage losses, an MPC placement technique was proposed, in conjunction with using lost circulation fiber technology in the cement slurry and spacer. After addressing the losses and narrow working pressure window, the next main challenge was the extremely high temperature (Bottom hole static temperature of 171°C). Extensive lab testing provided the fluid solution: HT formulations for cement slurry and spacer to maintain stability and rheology for placement and management of equivalent circulating density and set cement properties for long-term zonal isolation. After the liner was run to bottom, the mud density was homogenized from 1.40 g/cc to 1.30 g/cc (pore pressure: 1.38 g/cc). During this process, 32.5 m3 of mud was lost to the formation. During the previous circulation, the backpressure required to maintain the equivalent circulation density (ECD) above pore pressure, which was calculated and validated resulting in 1,100 psi annulus surface pressure (close to the limit of the equipment capacity) during the stopping time. The cementing job was pumped flawlessly with only 10 m3 of mud loss at the end of the job. During reverse circulation, contaminated spacer at surface indicated no cementing fluid had been lost to the formation and adequate open-hole coverage. The liner was successfully pressure tested to 4,500 psi, and cement logs showed that the cement had covered the open hole completely. MPC is not a conventional cementing technique. After the successful result on this job and subsequent operations, this technique is now being adopted to optimize cementing in even deeper wells in Mexico, where losses during cementing operations in the past had modified or limited the whole well construction and designed completion, and production of the well.

Challenging Horizontal Well Abandoned with Innovative Plug Setting Technique and Tailored Slurry Design

2021 ◽  
Author(s):  
Dinesh Simmadorai ◽  
M Syafiq M Ariffin ◽  
Mayank Patil ◽  
David Franke ◽  
Aizat Noh ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Negative Impact ◽  
Cement Slurry ◽  
Horizontal Section ◽  
Support Tool ◽  
Main Challenge ◽  
Open Hole ◽  
Bottom Hole Assembly ◽  
Drilling Operations ◽  
Cement Plug

Abstract Setting multiple plugs across a horizontal well can be a challenge. One way to do this is using the "pump and pull" methodology to achieve the objectives set out by the project team. Tailoring of the cement slurries and the execution of cementing operations for the successful deployment of multiple cement plugs using this method to achieve a dependable barrier across a horizontal reservoir section will be reviewed and discussed. A development well in Malaysia lost a bottom hole assembly (BHA) in their 8.5" hole section. This resulted in the requirement to abandon a long horizontal section along with the requirement to spot a 2,100 ft continuous cement plug on top of the BHA to abandon the well. The main challenge for setting a cement plug across a horizontal section, is cement slumping and stuck pipe, which might result in repeating cement plug jobs or non-productive time having a negative impact on well economics. To achieve isolation objectives in the first attempt, this long continual plug was broken up amongst four smaller individual plugs "stacked" on top of each other. The first 3 plugs were designed to each be 600 ft in length followed by a 340 ft plug. To avoid cement slumping, a cement support tool was deployed above the BHA before the first plug in the horizontal section. The first three plugs were placed in the horizontal open hole section and the fourth plug was placed at an inclination of 75 degrees, all using the "pump and pull" method. The pump and pull method is a common practice for worker operations with coil tubing and this similar technique can be applied in ERD drilling operations to aid in the homogeneous and accurate placement of cement plugs. However, for this job, the pump and pull placement method was preferred to aid in the homogenous and accurate placement of cement slurry through the horizontal open hole section. Detailed job calculations, the slurry design which was tailored for this application along with detailed operational procedures which resulted in the successful placement of all plugs on the first attempt under challenging well conditions will all be discussed. The approach utilized here resulted in the successful placement of a 2,100 ft continuous plug which isolated the BHA and saved the project valuable rig time. Similar approaches can be used in other areas to achieve successful results in first attempts to help well economics.

Failure Analysis of the Tripping Operation and its Impact on Well Control

2015 ◽  
Author(s):  
Majeed Abimbola ◽  
Faisal Khan ◽  
Vikram Garaniya ◽  
Stephen Butt
Keyword(s):  
Human Error ◽  
Integrated Control ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Well Control ◽  
Lost Circulation ◽  
Critical Elements ◽  
Open Hole ◽  
Critical Components ◽  
The Cost

As the cost of drilling and completion of offshore well is soaring, efforts are required for better well planning. Safety is to be given the highest priority over all other aspects of well planning. Among different element of drilling, well control is one of the most critical components for the safety of the operation, employees and the environment. Primary well control is ensured by keeping the hydrostatic pressure of the mud above the pore pressure across an open hole section. A loss of well control implies an influx of formation fluid into the wellbore which can culminate to a blowout if uncontrollable. Among the factors that contribute to a blowout are: stuck pipe, casing failure, swabbing, cementing, equipment failure and drilling into other well. Swabbing often occurs during tripping out of an open hole. In this study, investigations of the effects of tripping operation on primary well control are conducted. Failure scenarios of tripping operations in conventional overbalanced drilling and managed pressure drilling are studied using fault tree analysis. These scenarios are subsequently mapped into Bayesian Networks to overcome fault tree modelling limitations such s dependability assessment and common cause failure. The analysis of the BN models identified RCD failure, BHP reduction due to insufficient mud density and lost circulation, DAPC integrated control system, DAPC choke manifold, DAPC back pressure pump, and human error as critical elements in the loss of well control through tripping out operation.

Use Of Fiber Materials to Mitigate Lost Circulation During Cementing Operations in Turkmenistan

2021 ◽  
Author(s):  
Amanmammet Bugrayev ◽  
Svetlana Nafikova ◽  
Salim Taoutaou ◽  
Guvanch Gurbanov ◽  
Maksatmyrat Hanov ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Control Treatment ◽  
Cement Slurry ◽  
Lost Circulation ◽  
Innovative Materials ◽  
Primary Cementing ◽  
Fit For Purpose ◽  
Fiber Materials ◽  
Fracture Gradient ◽  
Application Requirements

Abstract Lost circulation in depleted sands during a primary cementing job is a serious problem in Turkmenistan. The uncertainty in formation pressure across these sands increases the risk of losses during drilling and cementing, which results in remedial operations and nonproductive time. The need to find a fit-for-purpose lost circulation solution becomes even more critical in an environment with narrow pore pressure-to-fracture gradient, where each cement job with losses compromises the downhole well integrity. An engineered lost circulation solution using innovative materials in the cement slurry was carefully assessed and qualified in the laboratory for each case to optimize the formulation. The lost circulation control treatment combines specialized engineered fibers with sized bridging materials to increase the effectiveness of treatment, formulated and added to the cement slurries based on the slurry solids volume fraction (SVF). Cement slurries with low SVF were treated with higher concentrations of the product and slurries with high SVF used lower concentrations. More than 50 jobs were performed with cement slurries designed at various densities and SVF up to 58% and using this advanced lost circulation material (LCM) to mitigate losses during cementing. Field experience showed positive results, where the differential pressure up to 2,800 psi was expected during cementing operation. A local database, generated based on the design and development work performed, enabled improved decision-making for selection and LCM application requirements for subsequent jobs and development of a lost circulation strategy. The mitigation plan was put in place against losses in critical sections and depleted sand formations in Turkmenistan. It assisted in meeting the cement coverage requirements on numerous occasions, improving overall the integrity of the wells and thus, was considered to be a success. This paper provides insight of this advanced LCM, its application in cement slurries, the logic behind the developed loss circulation strategy, and the high success rate of its implementation. Three case histories are presented to demonstrate the strategy and results.

Infill Depleted Gas Well Cementing Challenges for Offshore Myanmar Drilling Operations

2021 ◽  
Author(s):  
Ajita Ang C K Ang ◽  
Avinash A Kumar Kumar ◽  
Syazwan B A Ghani Ghani ◽  
Nann N N Maung Nann ◽  
M Hanif Yusof Yusoff ◽  
...  
Keyword(s):  
Water Production ◽  
Cement Slurry ◽  
Water Contact ◽  
Gas Well ◽  
Well Drilling ◽  
Depletion Rate ◽  
Open Hole ◽  
Drilling Operations ◽  
Sensitivity Studies ◽  
Remedial Work

Abstract Infill well drilling was planned and executed to increase production in a significantly depleted field. A total of 3 infill wells were drilled in 2 different layers of reservoir for an offshore operator in Myanmar. In the offset wells, water production had become significantly higher throughout. Previously all offset wells in this field were completed with open hole sand screens was chosen to isolate the water bearing sand in the sand reservoir below. Pore pressure prognosis were calculated from offset well depletion rate. Reservoir formation properties is assumed to be same throughout the field. The first well was drilled and was found that there were two gas water contacts through the 3 targeted sand layers. The gas water contact and WUT (Water Up To) in this well were unexpected and it was prognosed that these gas water contact are there due to compartmentalization. The 7" liner were set and cemented throughout these reservoirs. The cement job went as per the plan and there were no losses recorded during cementing. However, initial cement log did not show isolation. 2 more runs of cement log were performed 6 days and 10 days later while conducting intervention activities on other wells. All three cement log came to the same conclusion, showing no isolation throughout the annulus of the 7" production liner. Significant amount of gas had percolated into the annulus over time. Despite no evidence of poor cement slurry design observed during running various sensitivity studies and post-job lab tests final cement log, which was conducted under pressure and confirmed no hydraulic isolation. A cement remedial job was planned and an investigation was conducted to identify the plausible root causes. This paper explains on the root causes of poor cement presence in the annulus, and the remedial work that took place to rectify the issue.

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%.

Successful Single-Stage Cementing in a Weak Formation: A Case History in Spain

2014 ◽  
Author(s):  
A.. Bottiglieri ◽  
A.. Brandl ◽  
R.S.. S. Martin ◽  
R.. Nieto Prieto
Keyword(s):  
Engineering Design ◽  
Case History ◽  
Laboratory Testing ◽  
Single Stage ◽  
Formation Damage ◽  
Cement Slurry ◽  
Integrity Test ◽  
Open Hole ◽  
Zonal Isolation ◽  
Horizontal Wellbore

Abstract Cementing in wellbores with low fracture gradients can be challenging due to the risk of formation breakdowns when exceeding maximum allowable equivalent circulation densities (ECDs). Consequences include severe losses and formation damage, and insufficient placement of the cement slurry that necessitates time-consuming and costly remedial cementing to ensure zonal isolation. In recent cementing operations in Spain, the formation integrity test (FIT) of the open hole section indicated that the formation would have been broken down and losses occurred based on calculated equivalent circulating densities (ECDs) if the cement slurry had been pumped in a single-stage to achieve the operator's top-of-cement goal. As a solution to this problem, cementing was performed in stages, using specialty tools. However, during these operations, the stage tool did not work properly, wasting rig time and resulting in unsuccessful cement placement. To overcome this issue, the operator decided to cement the section in a single stage, preceded by a novel aqueous spacer system that aids in strengthening weak formations and controlling circulation losses. Before the operation, laboratory testing was conducted to ensure the spacer system's performance in weak, porous formations and better understand its mechanism. This paper will outline the laboratory testing, modeling and engineering design that preceded this successful single stage cementing job in a horizontal wellbore, with a final ECD calculated to be 0.12 g/cm3 (1.00 lb/gal) higher than the FIT-estimated figure.

Engineered Composite Lost Circulation Solution to Successfully Cure Total Losses During Drilling Across Naturally Fractured Formations in Ghawar Gas Field, Saudi Arabia

2021 ◽  
Author(s):  
Faizan Ahmed Siddiqi ◽  
Carlos Arturo Banos Caballero ◽  
Fabricio Moretti ◽  
Mohamed AlMahroos ◽  
Uttam Aswal ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Circulation System ◽  
Cement Slurry ◽  
Fiber System ◽  
Gas Field ◽  
Well Control ◽  
Lost Circulation ◽  
Carbonate Formation ◽  
Naturally Fractured ◽  
Zonal Isolation

Abstract Lost circulation is one of the major challenges while drilling oil and gas wells across the world. It not only results in nonproductive time and additional costs, but also poses well control risk while drilling and can be detrimental to zonal isolation after the cementing operation. In Ghawar Gas field of Saudi Arabia, lost circulation across some naturally fractured formations is a key risk as it results in immediate drilling problems such as well control, formation pack-off and stuck pipe. In addition, it can lead to poor isolation of hydrocarbon-bearing zones that can result in sustained casing pressure over the life cycle of the well. A decision flowchart has been developed to combat losses across these natural fractures while drilling, but there is no single solution that has a high success rate in curing the losses and regaining returns. Multiple conventional lost circulation material pills, conventional cement plugs, diesel-oil-bentonite-cement slurries, gravel packs, and reactive pills have been tried on different wells, but the probability of curing the losses is quite low. The success with these methods has been sporadic and shown poor repeatability, so the need of an engineered approach to mitigate losses is imperative. An engineered composite lost-circulation solution was designed and pumped to regain the returns successfully after total losses across two different formations on a gas well in Ghawar field. Multiple types of lost-circulation material were tried on this well; however, all was lost to the naturally fractured carbonate formation. Therefore, a lost-circulation solution was proposed that included a fiber-based lost-circulation control (FBLC) pill, composed of a viscosifier, optimized solid package and engineered fiber system, followed by a thixotropic cement slurry. The approach was to pump these fluids in a fluid train so the FBLC pill formed a barrier at the face of the formation while the thixotropic cement slurry formed a rapid gel and quickly set after the placement to minimize the risk of losing all the fluids to the formation. Once this solution was executed, it helped to regain fluid returns successfully across one of the naturally fractured zones. Later, total losses were encountered again across a deeper loss zone that were also cured using this novel approach. The implementation of this lost-circulation system on two occasions in different formations has proven its applicability in different conditions and can be developed into a standard engineered approach for curing losses. It has greatly helped to build confidence with the client, as it contributed towards minimizing non-productive time, mitigated the risk of well control, and assisted in avoiding any remedial cementing operations that may have developed due to poor zonal isolation across certain critical flow zones.

Triple MPD Technique for Drilling and Intelligent Completion Deployment on an Abandoned Deepwater Well

2021 ◽  
Author(s):  
André Alonso Fernandes ◽  
Eduardo Schnitzler ◽  
Fabio Fabri ◽  
Leandro Grabarski ◽  
Marcos Vinicius Barreto Malfitani ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Fluid Loss ◽  
Final Project ◽  
Well Design ◽  
Open Hole ◽  
Loss Control ◽  
Fluid Losses ◽  
Complex Cases ◽  
Total Fluid

Abstract This is a case study of a presalt well that required the use of 3 different MPD techniques to achieve its goals. The well was temporary abandoned when conventional techniques failed to reach the final depth. Total fluid losses in the reservoir section required changing the well design and its completion architecture. The new open hole intelligent completion design had to be used to deliver the selective completion in this challenging scenario. From the hundreds of wells drilled in the Santos basin presalt, there are some wells with tight or no operational drilling window. In order to drill these wells different MPD techniques are used. In most cases, the use of Surface Backpressure (SBP) technique is suitable for drilling the wells to its final depth. For the more complex cases, when higher fluid loss rates occur, the use of SBP and Pressurized Mud Cap Drilling (PMCD) enables the achievement of the drilling and completion objectives. After the temporary abandonment of this specific well in 2018, the uncertainty of the pore pressure could not ensure that the SBP and PMCD techniques would be applicable when reentering the well. To avoid difficult loss control operations, the completion team changed the intelligent completion design to include a separated lower completion, enabling its installation with the MPD system. Besides the previously used MPD techniques, the integrated final project considered an additional technique, Floating Mud Cap Drilling (FMCD), as one of the possible contingencies for the drilling and completion phases. Well reentry and drilling of the remaining reservoir section included the use all the previously mentioned MPD techniques (SBP, PMCD and FMCD). The lower completion deployment utilized the FMCD technique to isolate the formation quickly and efficiently, without damaging the reservoir. The planning and execution of the well faced additional difficulties due to the worldwide pandemic and personnel restrictions. The success from the operation was complete with no safety related events and within the planned budget. At the end, the execution team delivered a highly productive well with an intelligent completion system fully functional, through an integrated and comprehensive approach. MPD use on deepwater wells is relatively new. Different operators used several approaches and MPD techniques to ensure safety and success during wells constructions over the last decade. This paper demonstrates the evolution of MPD techniques usage on deepwater wells.

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