A Novel Approach to Successfully Cement the Long Horizontal Liners Across Khuff-C Reservoir in High-Pressure Gas Producer Land Wells: A Case History from Saudi Arabia

2021 ◽  
Author(s):  
Wajid Ali ◽  
Freddy Jose Mata ◽  
Faisal Abdullah Al-Turki
Keyword(s):  
Drilling Fluid ◽  
Horizontal Wells ◽  
Gas Migration ◽  
Cement Slurry ◽  
Oil Companies ◽  
Temperature Modeling ◽  
Novel Approach ◽  
Open Hole ◽  
Zonal Isolation ◽  
Testing Field

Abstract Maintaining zonal isolation is vital to well economics and productive life. Well integrity is becoming more challenging with the drilling of deeper, highly deviated, and horizontal wells worldwide. Oil companies are focused on to enhance the well productivity during drilling long horizontal wells in a harsh environment by achieving maximum accessible reservoir contact. These wellbore geometries incorporate additional challenges to design and deliver a dependable barrier. In this paper, a case study about cementing the longest liner across Khuff-C reservoir has been presented discussing the main challenges, engineering considerations, field implementation, results, and conclusions. The well was drilled horizontally across Khuff-C carbonates using oil-based drilling fluid. The 5-7/8-in open hole section was planned to be cemented in single stage, utilizing 8370 ft of a 4-1/2-in liner. Careful attention was paid to estimate the bottom hole circulating temperature, using the temperature modeling simulator. A 118-lbm/ft3 slurry was designed to keep the equivalent circulation density intact. Gas migration control additives were included in the slurry design to lower the slurry's transition time, in order to reduce the chances of gas migration through the cement slurry. The slurry was batch-mixed to ensure the homogeneity of the final slurry mixture. A reactive spacer was designed to improve the cement bonding from long term zonal isolation perspective. Additionally, the spacer was loaded with optimum amounts of surfactant package to serve as an aid to remove the mud and to water-wet the formation and pipe for better cement bonding. Centralizers placement plan was optimized to allow around 63% average standoff around the pipe, staying within the torque and drag (T&D) limits. The cement treatment was performed as designed and met all zonal isolation objectives. The process of cementing horizontal liners comes with unique procedures. There are several challenges associated with carrying out wellbore zonal isolation for primary cementing of horizontal liners, therefore, a unique level of attention is required during the design and execution stages. The slurry design requires careful formulation to achieve the desired specifications while ensuring its easy deployment and placement in the liner annulus. By planning in advance and following proven techniques, many of the problems associated with the running and cementing of deep and long horizontal liners can be alleviated. This paper highlights the necessary laboratory testing, field execution procedures, and treatment evaluation methods so that this technique can be a key resource for such operations in the future. The paper describes the process used to design the liner cement job and how its application was significant to the success of the job.

The Research and Application of Cementing Isolation Technology in High Porosity and Permeability of Developed Clastic Rock Reservoir in Tarim Basin

2021 ◽  
Author(s):  
Hongtao Liu ◽  
Zhengqing Ai ◽  
Jingcheng Zhang ◽  
Zhongtao Yuan ◽  
Jianguo Zeng ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
Water Layer ◽  
High Porosity ◽  
Self Healing ◽  
Cement Slurry ◽  
Clastic Rock ◽  
Pump Rate ◽  
Porosity And Permeability ◽  
Zonal Isolation ◽  
High Pump

Abstract The average porosity and permeability in the developed clastic rock reservoir in Tarim oilfield in China is 22.16% and 689.85×10-3 μm2. The isolation layer thickness between water layer and oil layer is less than 2 meters. The pressure of oil layer is 0.99 g/cm3, and the pressure of bottom water layer is 1.22 g/cm3, the pressure difference between them is as bigger as 12 to 23 MPa. It is difficult to achieve the layer isolation between the water layer and oil layer. To solve the zonal isolation difficulty and reduce permeable loss risk in clastic reservoir with high porosity and permeability, matrix anti-invasion additive, self-innovate plugging ability material of slurry, self-healing slurry, open-hole packer outside the casing, design and control technology of cement slurry performance, optimizing casing centralizer location technology and displacement with high pump rate has been developed and successfully applied. The results show that: First, the additive with physical and chemical crosslinking structure matrix anti-invasion is developed. The additive has the characteristics of anti-dilution, low thixotropy, low water loss and short transition, and can seal the water layer quickly. Second, the plugging material in the slurry has a better plugging performance and could reduce the permeability of artificial core by 70-80% in the testing evaluation. Third, the self-healing cement slurry system can quickly seal the fracture and prevent the fluid from flowing, and can ensuring the long-term effective sealing of the reservoir. Fourth, By strict control of the thickening time (operation time) and consistency (20-25 Bc), the cement slurry can realize zonal isolation quickly, which has achieved the purpose of quickly sealing off the water layer and reduced the risk of permeable loss. And the casing centralizers are used to ensure that the standoff ratio of oil and water layer is above 67%. The displacement with high pump rate (2 m3/min, to ensure the annular return velocity more than 1.2 m/s) can efficiently clean the wellbore by diluting the drilling fluid and washing the mud cake, and can improve the displacement efficiency. The cementing technology has been successfully applied in 100 wells in Tarim Oilfield. The qualification rate and high quality rate is 87.9% and 69% in 2019, and achieve zone isolation. No water has been produced after the oil testing and the water content has decreased to 7% after production. With the cementing technology, we have improved zonal isolation, increased the crude oil production and increased the benefit of oil.

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.

Comparative experimental evaluation of drilling fluid contamination on shear bond strength at wellbore cement interfaces

2014 ◽  
Vol 11 (6) ◽  
pp. 597-604 ◽  
Author(s):  
Mileva Radonjic ◽  
Arome Oyibo
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Cement Slurry ◽  
Geothermal Wells ◽  
Sustained Casing Pressure ◽  
Zonal Isolation ◽  
Casing Pressure ◽  
The Impact

Wellbore cement has been used to provide well integrity through zonal isolation in oil and gas wells as well as geothermal wells. Failures of wellbore cement result from either or both: inadequate cleaning of the wellbore and inappropriate cement slurry design for a given field/operational application. Inadequate cementing can result in creation of fractures and microannuli, through which produced fluids can migrate to the surface, leading to environmental and economic issues such as sustained casing pressure, contamination of fresh water aquifers and, in some cases, well blowout. To achieve proper cementing, the drilling fluid should be completely displaced by the cement slurry, providing clean interfaces for effective bond. This is, however, hard to achieve in practice, which results in contaminated cement mixture and poor bonds at interfaces. This paper reports findings from the experimental investigation of the impact of drilling fluid contamination on the shear bond strength at the cement-formation and the cement-casing interfaces by testing different levels of contamination as well as contaminations of different nature (physical vs. chemical). Shear bond test and material characterization techniques were used to quantify the effect of drilling fluid contamination on the shear bond strength. The results show that drilling fluid contamination is detrimental to both cement-formation and cement-casing shear bond strength.

Wellbore Stabilizing Technology Enhances Cementing Efforts in the North Sea

2021 ◽  
Author(s):  
Agnieszka Ilnicka ◽  
Antonio Bottiglieri ◽  
Maja Jaskiewicz ◽  
David Kulakofsky
Keyword(s):  
North Sea ◽  
Drilling Fluid ◽  
Cement Slurry ◽  
Weak Zone ◽  
Two Fluids ◽  
The North ◽  
Zonal Isolation ◽  
The North Sea ◽  
Isolation Requirements ◽  
Cement Integrity

Abstract North Sea lithologies are often complex creating a difficult environment to deliver effective zonal isolation with standard cementing practices. With ever-present weak, fractured, and unconsolidated formations, the practice of fully lifting heavier cement up the annular gap between the formation and the casing or liner often times compromises the formation and the cement integrity. Wellbore Stabilizing (WBS) technology has been shown capable of providing zonal isolation under these difficult conditions. A cementing spacer has been developed that incorporates WBS technology providing a simple way to deliver the technology in front of any cement job, without compromising the cement integrity or requiring any last-minute slurry design or redesign. By separating the placement of the WBS technology from the cement itself, the cement slurry can be designed with the sole focus being on the interval's zonal isolation requirements. On Askepott wells in the Norwegian part of the North Sea, the Nordland weak zone is encountered after drilling out the 30-inch shoe from the Oseberg Vest H template. Cement back to the seafloor is required when cementing the 20-in casing in these 26-in. holes. Prior to the introduction of the WBS technology, pressure had been observed on the D-annulus, hinting at a lack of sufficient cement circulation. With assistance from this new WBS spacer, pressure is no longer observed in the D-annulus indicating the cement is now being circulated back inside of the conductor string. The WBS spacer has also been used successfully ahead of cement across the production interval in wells where losses were typically expected, and again full returns were observed. Normally cement spacers are utilized to separate the drilling fluid from the cement as these two fluids are normally incompatible with each other and to help push the drilling fluid out of the well so the annulus may be completely filled with cement. If the drilling fluid is not successfully displaced from the annular space, the zonal isolation intended by the primary cement job is usually less than ideal. In addition to these standard functions in preparation for cementing operations, this specialized WBS spacer also can prevent loss of cement to the formation.

A Novel Approach of Cuttings Transport with Bubbles in Horizontal Wells

2012 ◽  
Vol 524-527 ◽  
pp. 1314-1317 ◽  
Author(s):  
Ying Ying Li ◽  
Guan Cheng Jiang ◽  
Ling Li ◽  
Wei Xing Xu ◽  
Zhi Heng Zhao
Keyword(s):  
Surface Area ◽  
Drilling Fluid ◽  
Horizontal Wells ◽  
Experimental Results ◽  
Drilling Process ◽  
Cuttings Transport ◽  
Horizontal Section ◽  
Transport Effect ◽  
Novel Approach ◽  
Cutting Bed

Aiming at the cutting bed settling problems in horizontal section during drilling process, a novel additive FGC for cuttings transport is applied. The experimental results show that the wettability was converted to amphiphobic and the cuttings preferentially attached to gas bubbles after FGC adsorption on the cuttings’ surface. The surface area of the cuttings is increased and the density of it is reduced, making cuttings more easily to be driven by liquid and settlement decrease. Tested by the horizontal simulation device, the cuttings transport effect is good and most of cuttings can be circulated to the outlet position by drilling fluid.

Successful Application of a Reinforced Composite Mat Pill Technology for Lost Circulation Control in the Norwegian Continental Shelf

2021 ◽  
Author(s):  
Jose A. Barreiro ◽  
John S. Knowles ◽  
Carl R. Johnson ◽  
Iain D. Gordon ◽  
Lene K. Gjerde
Keyword(s):  
Continental Shelf ◽  
Flow Rate ◽  
Drilling Fluid ◽  
Significant Loss ◽  
Lessons Learned ◽  
Cement Slurry ◽  
Lost Circulation ◽  
Reinforced Composite ◽  
Zonal Isolation ◽  
Norwegian Continental Shelf

Abstract An operator in the Norwegian continental shelf (NCS) required sufficient zonal isolation around a casing shoe to accommodate subsequent targeted injection operations. Located in the Ivar Aasen field, and classified as critical, the well had a 9 ⅝-in. casing shoe set in the depleted Skagerrak 2 reservoir. The lost circulation risk was high during cementing because the Hugin formation, located above the reservoir, contained 40 m [~ 131.2 ft] of highly porous and permeable sandstone. During previous operations in the field, lost circulation was observed before and during the casing running and cementing operations. After unsuccessful attempts to cure the losses with various lost circulation materials, a new solution was proposed to target the specific lost circulation problem by combining two types of reinforced composite mat pill (RCMP) technology. Specifically, the first type of RCMP technology was engineered for use in the viscous preflush spacer, and the second was applied to the cement slurry itself. Working in synergy, the RCMP systems mitigated the risk of incomplete zonal isolation. With no losses observed upon reaching total depth (TD) for the 12 ¼-in. hole, the 9 ⅝-in. casing was run with a reamer shoe and 15 rigid centralizers. Between 2700 and 2728 m [~ 8,858 and 8,950 ft] measured depth (MD), the rig observed constant drag of 30 to 40 MT whilst working the casing down, and circulation was completely lost before partial returns were eventually observed. The rig continued to work the string down to the planned landing depth at 3897 m [~ 12,785 ft] MD. Precementing circulation ensued with staged pump rates increasing at 100-L/min [~ 0.6-bbl/min] intervals up to 1400 L/min [~ 8.8 bbl/min], which induced losses at a rate of 6.5 m3/hour [~ 40 bbl/hour]). Subsequently, the flow rate was reduced to 1300 L/min [~ 8.1 bbl/min], and the annular volume was circulated 2.6 times with full returns. Attempts to reduce equivalent circulating density (ECD) ahead of the cementing operation were implemented at 1300 L/min [~ 8.1 bbl/min] using a low-density, low-rheology oil-based drilling fluid pill. However, a significant loss rate of 18.0 m3/hour [~113 bbl/hour] was observed. The flow rate was reduced to 950 L/min [~ 6.0 bbl/min], and partial circulation was recovered. After the spacer and cement had reached the annulus, full returns were immediately observed and continued until the top plug was successfully bumped. Acoustic logging determined that the operation had achieved the primary job objective of establishing the required length of hydraulically isolating cement in the annulus. Lost circulation is a costly problem that can be difficult to solve, even with the wide variety of technologies available (Vidick, B., Yearwood, J. A., and Perthuis, H. 1988. How To Solve Lost Circulation Problems. SPE-17811-MS). This case study demonstrates a successful solution. The operator will be able to incorporate lessons learned and best practices into future operations, and these lessons and practices will be useful to other operators with similar circumstances.

A Novel Approach to Drill Stem Selection for Drilling in Sour Fields

2021 ◽  
Author(s):  
Guillaume Plessis ◽  
Andrei Muradov ◽  
Laurent Bordet ◽  
Richard Griffin ◽  
Lucien Hehn
Keyword(s):  
Drilling Fluid ◽  
Drill Pipe ◽  
High Strength ◽  
Drill String ◽  
Oil Companies ◽  
Technology Leader ◽  
Drill Stem ◽  
Novel Approach ◽  
Sulfide Stress ◽  
Sour Service

Abstract For years the drilling industry has used sour service drill pipe within a narrow set of specifications and industry guidelines. That left room for original equipment manufacturers (OEM) to have customization on an iterative basis, which resulted in a wide product offering to fulfill operator needs. While this method worked, it did not lead to building the product in the most efficient and economical manner. As a result of this product diversity, drilling engineers could specify the best product to deliver their projects when running drilling models, only to have to redesign it around what is effectively available on rigs or for rental. This disconnect puts pressure on the industry players and is the result of a lack of standardization. We wiped the board to provide a simple solution that is more suited to allow alignment between operators, contractors, and rental companies. The new philosophy is based on the National Association of Corrosion Engineers (NACE) MR0175-2015 severity diagram, where environmental severity is defined in regions (1, 2, and 3), which have been used by oil companies’ engineers for their oil country tubular goods (OCTG) product selection. Even though the drill string will not be exposed to the well fluid for the same extended time and is surrounded by a more forgiving medium, the drilling fluid, the diagram allows a segmentation of customer's needs. This framework helped define targeted product properties. A research and development (R&D) and industrialization test campaign could then be started to confirm that sound product configurations could be offered with targeted properties. The study also explored the limitations imposed on connection make-up torque in a sour gas environment relative to the NACE severity diagram. Emphasis was given on methods to increase the make-up torque, which is needed to deliver the most extended reach wells that are now commonplace. The result of this two-year development campaign is a short list of grades with an optimized balance between pipe subcomponents strength and sulfide stress cracking (SSC) resistance. Region 1 (mild severity) products will offer as much tension and torque as possible, matching or exceeding these of API products, including excellent resistance to SSC, thus making drilling operation safer. Region 2 (medium severity) will offer products with medium to high strength and enhanced SSC resistance. Finally, region 3 (high severity) products will be aligned with the industry specifications for maximized SSC resistance and lower strength. This paper discusses a proactive approach that contrasts with a historical, more reactive one. As the drill stem technology leader, we saw an opportunity to drive this initiative that will benefit the drilling industry by offering a more natural way to select drill stem products. For the first time a sour service product range aligns with the needs of drilling engineers and the inventory of their selected service companies.

Successful Off Bottom Cementation of a Highly Deviated 4 ½ in Production Liner in UAE

2021 ◽  
Author(s):  
Ahmedagha Hamidzada ◽  
Ahmed Rashed Alaleeli ◽  
Azza El Hassan ◽  
Fatima Bin Tarsh ◽  
Islam Abdelkarim
Keyword(s):  
Drilling Fluid ◽  
High Viscosity ◽  
High Yield ◽  
Cement Slurry ◽  
Engineering Approach ◽  
Main Challenge ◽  
Narrow Side ◽  
Fluid Properties ◽  
Zonal Isolation ◽  
Cement Integrity

Abstract Cementing a highly deviated production liner is associated with cement placement challenge that can compromise zonal isolation. A major operator in UAE, was facing a challenge to cement 4 ½ in slim production liner set at + 5000 ft off-bottom. The corresponding 6 in. section was drilled with a relatively high mud weight in the range of 12 to 13 PPG. One of the main challenge was the risk of solids settling on the low side of the wellbore, making mud displacement difficult to achieve while cementing. Additionally, cementing off-bottom without an ECP in a highly deviated wellbore with multiple exposed production zones, further increased cement placement complexity. A holistic engineering approach was integrated to ensure successful zonal isolation. Wellbore parameters and fluid properties were critically evaluated. To overcome off-bottom cementing and prevent slurry fallback risks, a weighted high viscosity pill with high yield point was placed as a temporary basement to support the cement column and isolate the reservoir during 4 ½ in liner job. After placement of the pill, the wellbore was observed for flow checks to ensure stable downhole conditions prior to displacing the drilling fluid across the liner interval to brine within the same density. A centralization program was implemented to achieve more than 70% stand-off which required a minimum centralization pattern of two rigid centralizers per joint which helped minimize the presence of mud channels on the narrow side. Effective mud removal was ensured through implementation of a spacer train in front of the cement. The first spacer was pumped with same mud density to reduce ECD followed by another advanced low invasion loss circulation spacer to mitigate losses as well as provide a sustained downhole rheology. A resilient, expandable and gas tight cement slurry, was selected to target long-term zonal isolation. Multiple hydraulic simulations were performed to optimize ECDs and ensure safe margins during placement A CFD (computational fluid dynamics) model was utilized to simulate hydraulics, expected mud removal and fluids inter-mixing especially during liner rotation. In addition, the model simulated high-calculated torques based on flow restrictions through liner hanger assembly. Lack of mechanical liner movement was compensated by additional pre-job circulation to fully condition the wellbore. The job was executed with no losses during cementing, and spacer and cement returns were received on the surface during reverse out. Utilizing the best engineering approach, practices, and techniques from this job is implemented in the future wells as the production of the well is directly affected by the cement quality. Post job cement integrity evaluation via a cement bond log confirmed excellent bonding of cement to the liner and reservoirs across the entire open-hole interval.

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