Successful to Isolate Original Reservoir by Coiled Tubing Cementing for Workover Wells

2021 ◽  
Author(s):  
Takeru Okuzawa ◽  
Kushal Gupta ◽  
Tetsuro Takanishi ◽  
Ahmedagha Eldaniz Hamidzada
Keyword(s):  
Sea Water ◽  
Operation Time ◽  
High Viscosity ◽  
Cement Slurry ◽  
Major Drawback ◽  
Coiled Tubing ◽  
Zonal Isolation ◽  
Well Abandonment ◽  
Control Loss ◽  
Operational Time

Abstract In workover phase prior to commencing sidetrack operation, it is required to recover old existing completion string for isolating & abandoning existing reservoir section in accordance with well integrity and global well abandonment standards. Prior to utilization of the coiled tubing cementing approach, the practice was to recover all existing completion by cutting and pulling out the dual tubing or mill the permanent packer. After all the completion recovery, spot and squeeze cementing operations were conducted. However a major drawback of this process is, until recovering some part of completion string, the actual physical condition of the completion strings remains unknown and it poses high risk to get stuck in cased hole or end up in loosing accessibility inside completion string due to corrosion. Furthermore, in some of the old wells had failure to recover completion components like a dual flow assembly and a dual packer due to completion age, had led to improper zonal isolation. Even if all the old existing completion is recovered successfully, it consumes a lot of operation time and several fishing trips with overshot or junk mill BHA (Bottom Hole Assembly). In order to minimize the risk of being stuck or loosing accessibility and ending up failing to recover existing completion and to save operational time, the coiled tubing cementing was conducted to isolate existing reservoir and leave remaining parts of completion downhole. During the operation phase, injectivity test was performed by pumping sea water followed by bull heading kill fluid in to the reservoir. Losses rate was evaluated while observing the well, a high viscosity pill was spotted in order to treat losses and control loss rate. Coiled tubing was rigged up on Long string and run in hole to tag a landing nipple in existing completion string in order to have reference of depth corrected against ORTE (Original Rotary Table Elevation) depths while using the coiled tubing for operations. After having correct reference of depth with tagging completions nipple accessory, coiled tubing with slim OD cementing BHA was run in hole to tag PBTD (Plug Back Total Depth) and then picked up to certain depth while spotting cement slurry at controlled speed. Once the complete amount of slurry was spotted during picking up coiled tubing was pulled out to be away from cement slurry and then coiled tubing BOP (Blow Out Preventer) was closed and cement was squeezed in to the formation. After squeezing pre determined volume or archiving the lock up pressure, coiled tubing was pulled further up and circulated out to ensure all cement slurry out from coiled tubing (inside and outside). Top of cement was confirmed by tagging with the milling assembly connected to coiled tubing and the pressure test was performed after waiting on cement to confirm the integrity of the barrier. For short string, similar abandonment plug process was followed as that of the long string. After performing tagging operations, cement was spotted while pulling out the coil tubing to certain depth and then coil tubing was picked up above the cement to squeeze cement in to the formation. Similar coiled tubing cement operation for isolating lower perforations was performed on three other wells, and proper zonal isolation was achieved against reservoirs. This improved approach of abandoning lower reservoir prior to completions recovery proved to save 2-3 days of rig operational time in comparison to previous operations practices of recovering existing completion completely & then perform cementing operations for zonal isolation against each reservoir. Based on the successful result in three wells, it is concluded that this coiled tubing cement operation is effective for zonal isolation and provide savings in operation days.

Optimization of Operational Time and Workover Resources With the Alternate Use of Coiled Tubing and Pulling Unit for Well Abandonment

2011 ◽  
Author(s):  
Angel Pando ◽  
Luciano Bravo ◽  
Gustavo Cardona ◽  
Bladimir Lopez ◽  
Otoniel Acevedo
Keyword(s):  
Coiled Tubing ◽  
Well Abandonment ◽  
Operational Time

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.

Thru-Tubing Zonal Isolation and Water Shut-Off Utilizing Coiled Tubing in the Java Sea: Operational Challenge & Treatment Strategy

2004 ◽  
Author(s):  
Yoliandri Susilo ◽  
_ Hendarwin ◽  
Wahju Wibowo ◽  
Budhira L. Tobing ◽  
Arbai Imam ◽  
...  
Keyword(s):  
Treatment Strategy ◽  
Coiled Tubing ◽  
Zonal Isolation ◽  
Java Sea

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.

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.

Achieving Cementing Improvement in Horizontal Tight Gas Field Development

2015 ◽  
Author(s):  
Pungki Ariyanto ◽  
Mohamed.A.. A. Najwani ◽  
Yaseen Najwani ◽  
Hani Al Lawati ◽  
Jochen Pfeiffer ◽  
...  
Keyword(s):  
Tight Gas ◽  
Cement Slurry ◽  
Tight Sandstone ◽  
Gas Field ◽  
Full Field ◽  
Field Development ◽  
Horizontal Drain ◽  
Tight Reservoir ◽  
Design For All ◽  
Zonal Isolation

Abstract This paper outlines how a drilling team is meeting the challenge of cementing a production liner in deep horizontal drain sections in a tight sandstone reservoir. It is intended to show how the application of existing technologies and processes is leading to performance gain and improvements in cementing quality. The full field development plan of the tight reservoir gas project in the Sultanate of Oman is based on drilling around 300 wells targeting gas producing horizons at measured depths of around 6,000m MD with 1,000m horizontal sections. Effective cement placement for zonal isolation is critical across the production liner in order to contain fracture propagation in the correct zone. The first few attempts to cement the production liner in these wells had to overcome many challenges before finally achieving the well objectives. By looking at the complete system, rather than just the design of the cement slurry, the following criteria areas were identified: –Slurry design–Mud removal and cement slurry placement–Liner hanger and float equipment Improvements have been made in each of these areas, and the result has been delivery of a succesfully optimised liner cementing design for all future horizontal wells.

Real-Time Abrasive Perforation on Coiled Tubing Saves Operation Time, Improves Cost Efficiency, and Boots Reservoir Production in Delta Mahakam Field's Low-Porosity Reservoirs

2013 ◽  
Author(s):  
Tomi Sugiarto ◽  
Reza Aditya Wardhana ◽  
Somto Obiora Mezie-okoye ◽  
Imania Mustika Purwitaningtyas
Keyword(s):  
Real Time ◽  
Cost Efficiency ◽  
Operation Time ◽  
Coiled Tubing ◽  
Low Porosity
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