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Results
Robust Subsurface Drilling Hazards Assessment Reduces Well Drilling Cycle and Geological Non-Productive Time in an Onshore Pre-Caspian Basin Oil Field
Zhumadilov, Ulan (Geologist, TCO) | Baktybayeva, Kalampyr (Geologist, TCO) | Tlepbergenov, Nurbolat (Applied Reservoir Management Team Manager, TCO) | Manakhayev, Ruslan (G&G operations Supervisor, TCO) | Sargunanov, Marat (Advisor Geophysicist, TCO) | Puche, Ernesto (Chevron operations earth scientist)
Abstract Subsurface hazards assessment (SSHA) is an essential part of the well planning stage. Successful well execution depends on reducing geological uncertainties associated with hazards and it might prevent unexpected geological non-productive time (GNPT). Ultimately, SSHA can prevent possible catastrophic wellbore failure and loss of control in the drilling operation. The Pre-Caspian basin with its three megacomplexes has different geological hazards and requires unique drilling practices. Hazard mitigation plan can be developed both during well maturation and execution stages by acting accordingly. The approach should incorporate integrated analysis of geological, geophysical, and drilling data. Detailed SSHA and mitigation plan development are valuable constituents and basements for planning safe and cost-effective execution actions. The GNPT incurred due to insufficient recognition of geological uncertainties and underestimation of hazards can cost extra capital up to 30% of the total well execution expenditure. In addition, detailed SSHA is critical to deliver wells as designed ensuring reservoir penetration, formation evaluation and completion installation objectives are achieved fully, and future production is not compromised.
- North America > United States > New Mexico (0.40)
- Asia > Kazakhstan (0.29)
- Phanerozoic > Mesozoic (0.50)
- Phanerozoic > Paleozoic > Permian > Cisuralian > Artinskian (0.36)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Mineral (0.70)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.50)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (0.68)
- North America > United States > New Mexico > San Juan Basin > Basin Field (0.99)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Tengiz Formation (0.99)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Korolev Formation (0.99)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Drilling Operations (1.00)
- (7 more...)
Abstract The Suban field’s gas reservoir, located at approximately 2000 mTVDSS, is composed of Pre-Tertiary rocks including Igneous and Metasediments, as well as Tertiary sedimentary rocks like LTAF (Lower Talang Akar Formation) and BRF (Baturaja Formation). Before accessing the gas reservoir, drilling activities must navigate through overburden formations, predominantly shale-based Palembang and Telisa Formations. A particular challenge encountered within the Telisa Formation is the presence of overpressure conditions. Historically, drilling through overpressure-prone formations has posed formidable obstacles. Earlier approaches employed water-based mud (WBM) for drilling, which encountered issues such as shale instability and slow rate of penetration (ROP), necessitating the use of multiple drilling bits. In 2012, a shift was made to Synthetic Oil-Based Mud (SOBM) to address these challenges and enhance hole stability. The outcome was not only improved hole stability but also a noteworthy surge in the rate of penetration (ROP). Consequently, SOBM applications have been employed for drilling gas-fractured reservoirs in the Suban and Sumpal regions since 2012. However, the adoption of synthetic oil-based mud (SOBM) presented its challenges, including significantly higher costs compared to water-based mud (WBM) and challenges in handling and disposing of non-environmentally friendly drilling waste associated with SOBM. Recent developments have introduced High-Performance Water-Based Mud (HPWBM) as an alternative to Synthetic Oil-Based Mud (SOBM) for drilling. While HPWBM is not a complete replacement for SOBM, it aims to match its performance in terms of shale inhibition, wellbore stability, and rate of penetration (ROP). Additionally, HPWBM offers the potential for cost reduction and improved drilling performance. To incorporate HPWBM into the Suban field, a meticulous technical review and analysis were conducted to align the formulation with the reservoir’s mineralogy. The implementation was initially carried out in a specific Suban well, focusing on the 12.25" hole section due to overpressure. Key goals in designing the HPWBM included achieving superior shale inhibition, countering clay swelling and dispersion, and maintaining stability at high application temperatures. This alignment was particularly critical in the 12.25" section to minimize standpipe pressure (SPP) and Equivalent Circulating Density (ECD) and avoid formation fractures. A comprehensive laboratory testing process led to the development of 134 HPWBM formulations, with Formula 134 emerging as the optimal choice to fulfill the required objectives. The successful implementation of HPWBM, specifically formula 134, in the Telisa Formation marked its efficacy in delivering performance on par with SOBM. This achievement not only demonstrated cost-efficiency but also streamlined and effective drilling operations.
- Asia > Middle East > Saudi Arabia (1.00)
- Asia > Indonesia > Sumatra > South Sumatra (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Mineral > Silicate > Phyllosilicate (0.76)
- Asia > Indonesia > Sumatra > South Sumatra > South Sumatra Basin > Palembang Basin > Corridor Block > Suban Field > Talang Akar Formation (0.99)
- Asia > Indonesia > Sumatra > South Sumatra > South Sumatra Basin > Palembang Basin > Corridor Block > Suban Field > Fractured Basement Formation (0.99)
- Asia > Indonesia > Sumatra > South Sumatra > South Sumatra Basin > Palembang Basin > Corridor Block > Suban Field > Durian Mabok Formation (0.99)
- (5 more...)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
Implementation of Casing While Drilling Leading to Substantial Savings in West Kuwait Fields
Nasser, Al-Khalifa (Kuwait Oil Company, Ahmadi, Kuwait) | Farouk, M. H. (Kuwait Oil Company, Ahmadi, Kuwait) | Al-Muraikhi, H. R. (Kuwait Oil Company, Ahmadi, Kuwait) | Joshi, D. (Kuwait Oil Company, Ahmadi, Kuwait) | Al-Qazweeni, A,E. M. (Kuwait Oil Company, Ahmadi, Kuwait) | Elsheikh, Omar K. (SLB, Ahmadi, Kuwait) | Pasaribur, I. (SLB, Ahmadi, Kuwait) | Jokhi, Ayomarz H. (SLB, Ahmadi, Kuwait)
ABSTRACT Drilling across Shuaiba formation in the western wells of Kuwait poses significant difficulties, including severe loss of drilling fluid, unstable shale formations, and deteriorating hole conditions, which may require sidetracking. Cavernous porosity development in Shuaiba formation leads to potential severe lost circulation during drilling through it. This project aims to develop an engineered solution to efficiently drill through these challenges and to minimize nonproductive time, ultimately reducing the overall cost of the well. The proposed solution involves utilizing a casing-while-drilling technology that features a drillable bit, engineered to conform to the field's formations. It aims to drill through fractured dolomitic limestone and sandstone formations while simultaneously setting the casing. This paper will discuss the geological aspect of Shuaiba formation at the early Cretaceous that lead of the major mud losses, and the proposed engineering solution with casing while drilling for minimizing the non-productive time when drilling into Shuaiba formation. The selection process of using casing while drilling or conventional casing was also discussed because the completion requirement at the lower part of the reservoir section.
- Asia > Middle East > UAE (1.00)
- Asia > Middle East > Saudi Arabia (1.00)
- Asia > Middle East > Qatar (1.00)
- (4 more...)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (0.91)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.71)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.69)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Umm Gudair Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Umm Gudair Field > Marrat Formation > Najmah Formation (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Umm Gudair Field > Marrat Formation > Marrat "C" Formation (0.99)
- (15 more...)
- Well Drilling > Drilling Operations > Running and setting casing (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Taro Mucilage as Green Inhibitor in Water-Based Drilling Fluid to Modify the Rheological and Filtration Properties and Mitigating Shale Swelling Characteristics
Khan, Muhammad Arqam (Department of Petroleum Engineering, China University of Petroleum, East China, Qingdao, China) | Sheikh, Muhammad Aashan (Department of Petroleum Engineering, NED University of Engineering and Technology, Karachi, Pakistan) | Salman, Muhammad (Department of Petroleum Engineering, NED University of Engineering and Technology, Karachi, Pakistan) | Lalji, Shaine Mohammadali (Department of Petroleum Engineering, NED University of Engineering and Technology, Karachi, Pakistan) | Ali, Syed Imran (Department of Petroleum Engineering, NED University of Engineering and Technology, Karachi, Pakistan) | Li, Mei-Chun (Department of Petroleum Engineering, NED University of Engineering and Technology, Karachi, Pakistan) | Lv, Kaihn (Department of Petroleum Engineering, China University of Petroleum, East China, Qingdao, China) | Sun, Jinsheng (Key laboratory of Unconventional Oil & Gas, Development Ministry of Education, Qingdao, China)
Abstract Clay bearing shale formations tend to swell upon contact with water-based drilling fluid. The migration of hydrogen ions into the nano-spacing of shale platelets is mainly responsible for its disintegration and swelling. To mitigate the clay swelling problem, various shale stabilization materials are added in the water-based muds (WBMs). Before adding these additives, it is crucial to understand their physical and chemical interactions with clay minerals as well as within fluid. In this study, Taro Root Mucilage (TRM) is used as a green chemical in WBM to decrease the shale swelling characteristics. Taro root was boiled in distilled water at 40°C for 24 h and mucilage was prepared, which was characterized by FTIR and XRD pattern. It was then made part of a mud system, which then interacted with the shale sample collected from the western zone of Pakistan. Moreover, this mucilage was compared with sodium alginate mud system, a biopolymer commonly used in industry. The results of the experimental studies showed that TRM appreciably reduces clay swelling characteristics compared with the distilled water and sodium alginate. Moreover, all the rheological parameters fall under the recommended API range for TRM samples. Furthermore, it was found that the TRM produces a thin filter cake and minimizes fluid loss volume. In addition, during the shale cutting recovery test, 50%, 80% and 100% recoveries were obtained from base mud, whereas 10% and 20% were obtained from TRM based WBM respectively. TRM encapsulates the drilled cutting and preserves it from breaking into smaller fragments. In addition, TRM concentration in drilling mud increases the hydrophobicity of the shale sample. The adsorption of TRM over the surface of shale allows less penetration of water in the nano-spacing of shale structure and improves the shale stability. Hence, the finding in this article implies that TRM can be used as a green and sustainable substitute for traditional clay stabilizers in drilling operations to reduce formation damage. It has all the desired properties that help it to become an alternate solution in the form of a clay swelling inhibitor.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Mineral (1.00)
- Asia > Pakistan > Lower Indus Basin (0.99)
- Asia > China > Sichuan > Sichuan Basin (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Zubair Formation (0.98)
- (3 more...)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Formation Damage (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
Innovative Solution to Minimize Oil-Based Mud Formation Damage in Jurassic Depleted Reservoirs
Anood, Al-Dhafiri (Kuwait Oil Company) | Yousef, Al-Otaibi (Kuwait Oil Company) | Taha, Bloushi (Kuwait Oil Company) | Majdi, Al-Mutawa (Kuwait Oil Company) | Moudi, Al-Ajmi (Kuwait Oil Company) | Mamoun, Abdelbagi (SLB) | Martinez Sebastian, Sierra (SLB) | Mohammed, Abdel-Basset (SLB)
Abstract This document describes how the use of filter cake breaking fluid pills in non-cemented completions across North Kuwait Jurassic reservoirs increased the well's likelihood to be stimulated and produced. It describes the process to test this innovative solution before a well trial, the wells and environment in which they have been used, and their impact in the well's ability to communicate the borehole with the reservoir. The initial step was to identify which type of mud breaking pills could be used and available in the industry and use the current OBM dispersant pills as found in cement job spacers to enhance cement-reservoir contact. A target well screening was done to wells with possible non-cemented reservoir completions. The detailed operational procedure was then designed to consider the breaker volumes, the composition of the interface's spacer high viscosity pill, and the weight of the displacement fluid to account for the hydrostatic loss in the solids-free breaker volume into each of the wells’ geometries. Finally, these wells were stimulated and tested to identify if the new approach had enabled the wells to be productive and minimize the OBM's damage. The solution has been applied in three barefoot and one multi-stage completion wells. The first well's 380 ft 3-7/8" carbonate reservoir took 18 days to drill using 12.1 ppg OBM. Several calibration trips were done and on the final trip the 30 bbl mud breaking pill was displaced to replace the OBM within the open hole section. Post injectivity tests and an acid treatment, the well's initial production was 3 times the field average with a stabilization above field average gas production. In the second well, the 460 ft 3-7/8" section took 7 days to drill using 11.6 ppg OBM. This fluid was left in the hole to perform the acid treatment without achieving any injectivity. The entire reservoir section was then displaced with the mud breaking solution, for which injectivity and successful acid treatment and N2 activation achieved a final production rate comparable to the offset wells. In the third well, the 684 ft 3-7/8" reservoir took 3 days to drill with a 11.5 ppg OBM, which was displaced with the mud breaking pill using the drilling BHA before pulling it out of the hole. The well achieved immediate injectivity and higher than field average production. The fourth well was the first successful pilot in a multi-stage completion well, in which the OBM weight was initially lowered from 12 to 8.8 ppg, and then displaced by the breaker fluid prior to set the hanger and activate the packers. The use of filter cake breaking pills in barefoot wells achieved the purpose of facilitating the communication between the wellbore and the reservoir, requiring lower stimulation pressures, and minimizing formation damages that positively impacted the wells’ productivity.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)
- Well Drilling > Formation Damage (1.00)
- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- (5 more...)
Drilling Time Optimization by De-Risking a Re-Engineered Well Architecture Implemented in Offshore Shallow-Water Tertiary Wells in Gulf of Mexico
Barrera, Edison (SLB, Villahermosa, Tabasco, Mexico) | Gomez, Jose Manuel (SLB, Villahermosa, Tabasco, Mexico) | Alarcon, Jose (SLB, Villahermosa, Tabasco, Mexico) | Ponce, Jorge (SLB, Villahermosa, Tabasco, Mexico) | Torres, Maria Andrea (SLB, Villahermosa, Tabasco, Mexico) | Gonzalez, Pablo (SLB, Villahermosa, Tabasco, Mexico) | Hernandez, Gladys (SLB, Villahermosa, Tabasco, Mexico) | Hernández, Cesar (SLB, Villahermosa, Tabasco, Mexico) | Bravo, Carlos (SLB, Villahermosa, Tabasco, Mexico)
Abstract The Gulf of Mexico area is well known for the high complexity of its wells. Whether on deepwater or shallow-water fields, wells on each field require specific customization on wellbore architecture and drilling practices to drill faster without compromising well integrity standards, safety, and oil production. Wellbore architecture is essential for the success of drilling operations and ensure the lifetime of the well throughout production and interventions. In the early stages of field development, a conservative approach increases the chances of success and obtains all the relevant information for well production and drilling optimization. This project describes the successful implementation of an optimized 3 casing-strings wellbore geometry in two shallow-water fields, de-risking engineering and drilling practices applied to accelerate well delivery. Different challenges are present across the area, related to mechanical stuck pipe while crossing geological faults, unstable formations due to mechanical disturbance, differential stuck pipe due to heterogenous formation pressure with depleted sands, lost circulation on weak zones and collision with other wells departing from the same location. Additionally, many of the quality events occurred in these fields were associated to incorrect operational strategies implemented, mainly during BHA or casing tripping. In close coordination between G&G (Geological and Geophysical department) and drilling engineering, the new casing points were carefully selected Based on offset wells and logging data, the strategy was to maintain high parameters when conditions allowed it and adjust them while crossing weaker zones. The strategy to minimize the risk of pack-off while drilling required ensuring that the hole is cleaned properly while drilling at highest ROP, sweeping pills schedule, bridging material and reaming procedures before connection, minimizing pack-off risk while drilling and saving time with clean trips. A further step to enhance performance and prevent high impact events was to exploit opportunities for real-time monitoring to ensure procedural adherence and follow the measures in the detailed multi-disciplinary risk analyses for critical activities. Additionally, leveraging the improved architecture, an integral multi-bowl wellhead was designed and implemented, giving practical advantages for casing running, and operational time reduction.
- North America > Mexico (1.00)
- North America > United States > Texas > Dawson County (0.24)
- Geology > Geological Subdiscipline > Geomechanics (0.47)
- Geology > Structural Geology > Fault (0.35)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Well Planning > Trajectory design (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- (4 more...)
Influence of Nanoparticle-Based Drilling Fluids on Egyptian Shale Swelling – An Experimental Investigation
Mady, Ahmed (Belayim Petroleum Company, Cairo, Egypt) | Abdelhafiz, Mostafa M. (Petroleum Engineering Department, Future University in Egypt, Cairo, Egypt) | Dahab, Abdel Sattar (Mining, Petroleum, and Metallurgical Engineering Department, Cairo University, Cairo, Egypt) | Hegazy, Gehad M. (Petroleum Engineering Department, American University in Cairo, Cairo, Egypt) | Mahmoud, Omar (Petroleum Engineering Department, Future University in Egypt, Cairo, Egypt)
Abstract Shale swelling is a major challenge in drilling operations and can lead to severe problems. The use of shale swelling inhibitors and plugging additives in drilling mud is a common solution to mitigate these problems. This study aims at investigating the influence of aluminum oxide (Al2O3) and copper oxide (CuO) nanoparticles (NPs) as mud additives on Egyptian shale swelling. Two formations were studied, Duwi and Dakhla shales. X-ray diffraction (XRD) was utilized to reveal their clay mineralogy. Low-solid non-dispersed mud (LSNDM) was tested as the base fluid. LSNDM is a common choice to drill an intermediate section which may contain minor strikes of shaley and problematic formations. Al2O3-NPs (15 nm) and CuO-NPs (40 nm) were added at different concentrations (0.1, 0.3, 0.5, 0.7, and 1.0 wt%) and the rheological and filtration properties were tested using standard viscometer and API filter press. Oedometer tester was used to examine the effect of NPs-based LSNDM on shale swelling. Adding NPs to the LSNDM yielded better rheological behavior. An increase in the yield point (YP) was obtained when using 0.3 and 0.5 wt% of Al2O3-NPs and 0.1, 0.3 and 1.0 wt% of CuO-NPs, which implies less solids sagging, higher cuttings carrying capacity and thus, more efficient hole-cleaning. Furthermore, the gel strength (GS) of the LSNDM showed improvements when adding NPs compared to the base. Also, the Herschel-Bulkley model was found to best fit the rheological behavior of the NPs-based LSNDM. Moreover, using both NPs yielded better filtration properties, especially at 0.3 wt% of Al2O3-NPs and 1 wt% CuO-NPs. The scanning electron microscopy (SEM) images showed better surface morphology and less porous microstructure of the filter cakes containing 0.3 wt% of Al2O3-NPs and CuO-NPs compared to the base fluid. Also, a decrease in the slope of the filtrate volume curve after 30 minutes (up to 90 minutes) was observed compared to the base fluid, which confirms better NPs dispersion. The composition of the clay minerals ranged from 80% montmorillonite to low kaolinite content (19%) for Dakhla shales, and from 48% montmorillonite to low kaolinite content (22%) for Duwi shales as revealed by XRD, which suggests high swelling ability, especially for Dakhla shales. The Oedometer swelling measurements showed a reduction in Duwi shale swelling by 30 and 35% when using 0.3 wt% of Al2O3-NPs and CuO-NPs, respectively, compared to the base. In addition, a significant reduction in the swelling of Dakhla shale was obtained when using 0.3 wt% of Al2O3-NPs and CuO-NPs by 52 and 63%, respectively. This paper discusses a new application concerning the efficient use of NPs in the drilling fluid industry, which may promote using NPs-based mud to drill the Egyptian oil and gas wells.
- Africa > Middle East > Egypt (1.00)
- Europe (0.93)
- North America > United States > Texas (0.93)
- (5 more...)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Mineral > Silicate > Phyllosilicate (1.00)
- Africa > Middle East > Egypt > South Central Desert > Kombombo Basin > West Kom Ombo Concession > Duwi Formation (0.99)
- Africa > Middle East > Egypt > South Central Desert > Kombombo Basin > West Kom Ombo Concession > Dakhla Formation (0.99)
- North America > United States > New Mexico > Permian Basin > Atoka Field > San Andreas Formation (0.98)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Egypt Field (0.91)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
Successfully Drilled the 1st Undercut Profile Well Exposing the Reservoir Positioned Underneath the Surface Location into the Least Stress Direction, Case Study from Kuwait
Bashir, J. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Al-Khaja, M. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Taha, B. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Sindhu, S. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Al-Manaseer, A. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Ali., J. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Malik, A. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Al-Haddad, H. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Al-Otaibi, Y. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Jamal., J. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Ajmi, A. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Rashidee, T. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Al-Enezi, S. (Kuwait Oil Company, Ahmadi, State of Kuwait) | Nouh, W. (Halliburton Overseal Limited – Mina Abdullah, State of Kuwait) | Farhi, N. (Halliburton Overseal Limited – Mina Abdullah, State of Kuwait) | Ishak, G. (Halliburton Overseal Limited – Mina Abdullah, State of Kuwait)
Abstract First, find optimal KOP across the Top 16-in Section to have a smooth profile before building 11⁰ into the opposite side of the target reservoir point in Azimuth 325⁰ (the minimum stress direction) with a low Dog Leg Severity of 1.83º/100 ft to minimize the Casing wear expected while drilling the lower sections. Once started, the lower 12-1/4-in Section started to drop the 11⁰ inclination in Mutriba Formation with 2.86⁰/100’ DLS reaching back to Vertical in Mishrif Formation. By that level, it kicked off toward the reservoir direction in azimuth 145⁰ (the minimum stress direction), building an angle to 40⁰ inclination through five formations and holding this angle to the well TD in the bottom of the lower Burgan Formation. All risks and challenges were considered to drill the final 12 1/4-in Section throughout eight challenging formations in one run to the well TD that has always been drilled in one azimuth away from the least stress direction while keeping optimized Mud weight and Rheology for upcoming high permeable and depleted sand zones. This paper provides an overview about the preparations and execution of both the 16-in Top section with a low angle from the shallow formations, getting the required displacement in the opposite direction, and keeping all the section tangent to the 13-3/8-in Casing point to minimize the casing wear while drilling the 12-1/4-in Section. Addressed all the risks and challenges of drilling the 12 1/4-in section to the well TD through eight formations with different challenging behaviors as well as the wellbore pressure that always leads to splitting into two sections. It was a major challenge to wisely model the geo-mechanical characteristics of each formation and decide the mud weight range and rheology that can stabilize the wellbore through the eight formations with higher ECD values expected due to the undercut profile that can break formations and get mud losses to complete loss. A mitigation plan was executed to have a window of mud weight to stabilize the high-pressurized formation and ECD control for formation break avoidance. Consequently, optimizing mud weight and drilling parameters while managing differential stuck in Maudud depleted zones with close monitoring of real-time ECD at the same time helped into stabilize the high-pressurized zones and deliver the well to the desired TD. First time in Kuwait for the assigned direction company to drill an undercut profile throughout a long 12 1/4-in section, commingling eight formations with different properties and geo-mechanical reactions. Differential stuck hazards were addressed by geo-mechanical modeling for the eight formations to decide the mud weight window for optimum hole cleaning. Stabilize the pressurized formations controlling the ECD and ROP in some zones, achieving a ROP higher than the Average for the field. Following the best practice for hole cleaning allows to avoid breaking the other formations. Later, the longest production liner in the field was deployed and had excellent cement quality, providing optimal zonal isolation among the entire open hole segments.
- Asia > Middle East > Kuwait (0.88)
- Asia > Middle East > Qatar > Arabian Gulf (0.34)
- Geology > Geological Subdiscipline (0.68)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- Asia > Middle East > Qatar > Arabian Gulf > Arabian Basin > Arabian Gulf Basin > Block 6 > Al Khalij Field > Mishrif Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Rawdatain Basin > Lower Burgan Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Bahrah Field > Marrat Formation (0.99)
- (6 more...)
- Well Drilling > Pressure Management (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- (3 more...)
One Fracture at a Time - Saving Expenses on Lost Circulation Through 3D Far Field Sonic in the Gulf of Suez
Hegazy, Amr (General Petroleum Company) | Hakim, Emad Abdel (General Petroleum Company) | Saleh, Khaled (SLB) | Patro, Radhika (SLB) | Hussain, Syed Aaquib (SLB) | Sinha, Mrinal (SLB) | Abdulla, Mariam (SLB) | Ghanim, Mohamed (SLB) | Gomes, Renata (SLB) | Galal, Mahmoud (SLB) | Al-Mansour, Mansour (SLB)
Abstract Lost circulation is one of the significant challenges encountered while drilling in a depleted reservoir. Downhole mud loss problems get accentuated while drilling through highly permeable or fractured reservoirs or drilling with inadequate mud weight. Worldwide, the expenses due to mud loss can be significant in the drilling of a well. The presence of fractures can act as conduits for mud losses into the formation in a depleted reservoir. Hence, a comprehensive petrophysical and geomechanical evaluation was needed to identify and characterize these fracture networks. Though high-resolution image logs are the industry standard for identifying the presence of fractures, their shallow depth of investigation limits their information near the wellbore, and the extent of fractures in the far field couldn't be determined. Here, seismic, acoustics, and petrophysical data can shed information on the fractures at different levels. Understanding the stability of the detected fractures with the current-day stresses is vital in ascertaining its potential to support the flow of reservoir fluids. Thus, a collaborative workflow linking the high-resolution logs and deeper depth of investigation logs was devised for exhaustive characterization of the fractured reservoir. Drilling through the depleted formations of multiple reservoirs was challenging because of the lost circulation problems, with mud losses going as high as 140 bbls/hr. Detailed analyses of different acquired data were conducted to understand and evaluate this naturally fractured reservoir. Image interpretation showed the presence of fractures, vugs, and dissolution features in different densities across various encountered formations. Acquired acoustic monopole, dipole, and Stoneley data were studied in diverse domains to understand other properties: Stoneley reflection and transmission analysis provided information on the openness of the fractures in the near wellbore. Since an extensive fracture network creates intrinsic anisotropy in a formation, anisotropy analysis and sonic waveform dispersion analysis were carried out to identify and characterize the acoustically anisotropic zones. A forward modeling approach incorporating image interpretation and acoustic data were used to model and interpret acoustic anisotropy associated with geological features such as beddings and fractures. It provided a consistent solution, differentiating open fractures from closed ones. Acoustic reflection survey analysis delivered insight into laterally extensive fractures penetrating as deep as 20 m. Detailed geomechanical analysis hinted at current-day pore pressure and stresses acting on different formations and was used further for fracture stability analysis. This paper aims to describe how an integrated evaluation using geological, petrophysical, acoustic, and geomechanical analysis help delivers invaluable information on the laterally extensive, critically stressed fractures acting as primary culprits for severe mud losses, thus helping in optimizing the drilling of future wells to avoid mud losses in depleted fields.
- Asia > Middle East > Yemen (1.00)
- Asia > Middle East > Saudi Arabia (1.00)
- Africa > Middle East > Djibouti (1.00)
- (3 more...)
- Phanerozoic > Cenozoic > Neogene > Miocene (0.51)
- Phanerozoic > Mesozoic > Cretaceous (0.46)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.69)
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- Africa > Middle East > Egypt > South Sinai Governorate > Lagia Field > Thebes Formation (0.99)
- Africa > Middle East > Egypt > Gulf of Suez > Gulf of Suez Basin > Ras Gharib Field (0.99)
- Africa > Middle East > Egypt > Gulf of Suez > Gulf of Suez Basin > Matulla Formation (0.99)
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- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
Drilling Through Shales Below Depleted Sands: Case Study of a Niger Delta HPHT Gas Development Well
Ogbodu, Stella (Shell Petroleum Development Company of Nigeria Limited) | Tichelaar, Bart (Shell Petroleum Development Company of Nigeria Limited) | Amadi, Chibueze (Shell Petroleum Development Company of Nigeria Limited) | Anijekwu, Chinedu (Shell Petroleum Development Company of Nigeria Limited) | Eke, Kenneth (Shell Petroleum Development Company of Nigeria Limited) | Alli-Oluwafuyi, Jumah (Shell Petroleum Development Company of Nigeria Limited) | Schutjens, Peter (Shell Global Solutions International B.V Netherlands)
Abstract To sustain gas supply to NLNG T1-T7, it has become imperative to access deeper, geologically complex HPHT reservoirs in the Niger Delta. These hydrocarbon targets typically lie beneath hydrostatic geological intervals and are overlain by depleted and/or producing reservoirs hence choosing the right casing depth is a key parameter in executing HPHT wells In the wells in Astra East Field, it was decided to set a casing shoe in a homogeneous shale of ~200ft vertical thickness, located between overlying heavily depleted sand and underlying over pressured sand. This poses an interesting question of the direct practical importance: at what depth should the casing shoe be set to minimize the risk of kicks and/or wellbore instability (because of too low mud weight) and losses (because of too high mud weight). To help answer this question, wireline log data and drilling observations in other wells in the same field, where such shales were found, were analyzed, and evaluated. The electrical resistivity in the shales consistently showed the following signature from top to bottom across the shale: Zone 1: Relatively high electric resistivity just below the depleted sand, near constant with depth. Zone 2: The signature gradually decreasing with increasing depth, and finally, at the lower section of the shale. Zone 3: Relatively low electric resistivity just above the over pressured sand, the signal again near-constant with depth. The drilling observations revealed that wells with the casing set in Zone 1 experienced severe mud losses and differential sticking, while wells where the casing set in zones 2 or Zone 3 did not. This observation could be explained as follows - The electric resistivity signature as a function of depth (in the three zones described above) may reflect the pore pressure in the bounding sands: at the top, the shale "feels" the sand depletion, transmitted over the years via pore fluid pressure diffusion, which compacts the shale, presses the grains contacts closer together, thus increasing electrical resistivity. In contrast, at the base, the shale "feels" the overpressure in the sand below, maintained over the millions of years of geologic diagenesis. This keeps the deeper part of the shale at relatively low effective stress (compared to the upper part), with relatively low grain contact pressure, thus reducing electrical resistivity. We postulate that there may be a mechanism-based explanation for the heavy losses and sticking when the casing is set in Zone 1. We also inferred from the drilling data that the tendency to set the casing shoe quite shallow (in Zone 1) in previous wells and in the well in case study was driven by concern of wellbore instability and severe losses experienced while drilling through the intra-reservoir shale. Closer inspection reveals that this concern is probably not justified, as the apparently high risk of wellbore instability at the top of the shale was caused by using a too-high pore fluid pressure (i.e., one unaffected by the depletion of the sand on top of it). For future planned wells in the field, new LWD data acquisition practices have been developed for early detection of the onset of overpressures (top of Zone 2). This will improve the accuracy of casing point selection and the chances of successfully drilling across these intervals without well control issues.
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- Africa > Cameroon > Akata Formation (0.99)
- Well Drilling > Drilling Fluids and Materials (1.00)
- Well Drilling > Casing and Cementing > Casing design (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > HP/HT reservoirs (1.00)
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