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2021 ◽  
Author(s):  
Sudad H Al-Obaidi ◽  
Hofmann M ◽  
Smirnov VI ◽  
Khalaf FH ◽  
Hiba H Alwan

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottom hole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%.Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.


2021 ◽  
Author(s):  
Ahmed Al Mutawa ◽  
Ibrahim Hamdy ◽  
Eias Daban Al Shamisi ◽  
Bassem El Yossef ◽  
Mohamed Sameer Amin ◽  
...  

Abstract Biogenic gas resources have gathered importance recently due to its widespread availability, occurrence at geologically predictable circumstances, and existence at shallow depths. It is estimated that biogenic gas forms more than 20% of the global discovered reserves. However, the exploration and development of these unconventional resources come with numerous drilling and reservoir challenges. This paper showcases a novel approach used in the United Arab Emirates to overcome these challenges using managed pressure and underbalanced drilling. To tackle both reservoir and drilling challenges, a hybrid solution combining Underbalanced (UBD) and Managed Pressure Drilling (MPD) was applied. UBD was used to characterize the reservoir in terms of pressure and productivity index to ultimately enhance productivity by eliminating formation damage. MPD was used next to continue drilling through the problematic zone which had high instability due to the presence of highly sensitive salt, in addition to the presence of high pressure and loss zones. The fit for purpose hybrid application design allowed the operator to immediately switch between UBD and MPD conditions, as the well required with the same equipment. Three of the four targeted formations were in the 8 ½″ hole section, UBD was selected to drill the first reservoir formation which allowed pore pressure verification and avoided using excessive mud weight that was the culprit of many challenges like slow ROP, drilling fluid losses, bit balling, and fracking the formations. UBD has proved that mud weight can be reduced by 20%-30% comparing to conventional drilling. The second formation was a salt formation that has caused previously hole collapse and losses-kicks problems as heavy mud used to drill this salty formation. MPD used successfully drill this section by constant bottom hole pressure and lower mud weight as it was found from analyzing offset wells reports that hole collapse occurred at connections and pump off events. Constant Bottom Hole Pressure (CBHP) also eliminated tight spots and excessive reaming resulting in optimized drilling. The third formation used MPD as well to minimize overbalance pressure over previous sections while the fourth formation was drilled by UBD as it had a separate 6″ hole section as it formed an independent reservoir. The combined MPD and UBD approach eliminated most the NPT encountered in offset wells, enhanced Rate of Penetration (ROP) by 200% to 300% and slashed the well drilling time by 27 days.


2021 ◽  
Author(s):  
Rohan D'Souza ◽  
Chigozie Emuchay ◽  
Paul Neil ◽  
Jeffery Clausen

Abstract Previously, few options existed for the complex directional challenges. Drillers either needed to rely on multiple Bottom Hole Assemblies (BHAs) or use expensive drive systems, which resulted in increased operational cost and limited drilling flexibility. This novel Downhole Adjustable Motor (hereafter referred to as downhole adjustable motor or the motor) described in the paper addresses these limitations by enabling the driller to change the motor bend in real-time downhole. In addition, the motor can deliver up to 1,000 horsepower (HP) at the bit during rotary drilling—the highest power in its size range. This paper will review how, even in harsh drilling applications, the downhole adjustable motor has proven to save trips, increase bit life, reduce lateral vibrations and stick-slip, and allow for drilling optimization to increase Rate of Penetration (ROP) and decrease overall drill time. Whether for drilling contracts or lump-sum turnkey projects, the directional drilling industry benefits from this new technology's ability to improve drilling economics while increasing safety by reducing drillpipe tripping and additional BHA handling.


2021 ◽  
Author(s):  
Pasquale Pollio ◽  
Gianluca Fortunato ◽  
Salvatore Spagnolo ◽  
Gianni Baldassarri ◽  
Pasquale Cappuccio ◽  
...  

Abstract Water production has always afflicted mature fields due to the uneconomical nature of high water cut (WC) wells and the high cost of water management. Rigless coiled tubing (CT) interventions with increasingly articulated operating procedures are the key to a successful water reduction. In the scenario presented in this paper, high technological through tubing water shut off (WSO) for a long horizontal open hole (OH) well in a naturally fractured carbonate reservoir leads the way to new opportunities of production optimization. Engineering phase included sealant fluid re-design: the peculiar well architecture and fracture systems led to the customization of a sealant gel by modifying its rheological properties through laboratory tests, to improve effectiveness of worksite operations. A new ad-hoc procedure was defined, with a new selective pumping and testing technique tailored to each drain fracture. The use of Real-Time Hybrid Coiled Tubing Services (CT with fiber optic system coupled with real time capabilities of an electric cable) made it possible to optimize intervention reliability. Details of the operating procedure are given, with the aim of ensuring a successful outcome of the overall treatment Sealing gels are effective in plugging the formation, but in fractured environments the risk of losing the product before it starts to build viscosity is high. The success of the water shut off job has been obtained by using specific gel with thixotropic properties for an effective placement. In addition, the pumping has been performed in steps, each followed by a pressure test to assess the effectiveness of the plugging. Results are compared to two past interventions with equal scope in the same well: a first one with high volume of gel and an unoptimized pumping technique through CT and a second where a water reactive product was pumped by bullheading. The selective and repetitive approach pumping multiple batches of sealant system with CT stationary in front of a single fracture provided the best results from all three techniques. The real-time bottom hole data reading capability provided by hybrid CT allowed the placement of thru tubing bridge plugs (BP) with high accuracy and confidence with the ability to set electrically, therefore reducing risks related to hydraulic setting tools (i.e. premature setting). This also allows continual pumping during the run in hole (RIH) to clean up the zone prior to setting the BP. The combination of this innovative pumping technique and customization of the sealant fluid made it possible to achieve unprecedented water reduction in the field. The high technology CT supported the operation by providing continuous power and telemetry to the bottom hole assembly (BHA) for real time (RT) downhole diagnostics. Moreover, the operating procedures offer basic guidelines to successfully perform water shut off jobs in any other reservoir independent of its geological nature and structure.


2021 ◽  
Author(s):  
Krzysztof Karol Machocki ◽  
Abdulwahab Aljohar ◽  
David Zhan ◽  
Ayodeji Abegunde

Abstract A new down hole system and method to use for releasing stuck pipes is presented. New system design, features and limits are compared to commonly used techniques for releasing stuck pipe showing benefits of the new system when dealing with differential stuck pipe incidents. The new down hole system is capable to deliver much greater forces when compared to jars and other down hole accelerators near the stuck point. This system can generate over 40G`s lateral forces continuously down the hole acting on the stuck pipe area. The system can be integrated into a Bottom Hole Assembly (BHA) and activated once drill string become stuck or run as a part of the remediate assembly. Different aspects of two types of assemblies are described outlining the benefits and drawbacks. The author will discuss in details the background and rationale to the new technology, including a review of differential sticking challenges and functionality of this new system. The new system was compared to the most commonly used techniques for releasing differentially stuck pipe. Previously not releasable stuck pipe forces of over 1,000,000 lb. can now be overcome with the presented new approach to generate down hole forces near the stuck place. Flexibility in system integration and deployment allows for further optimization in BHA design and cost affective fishing operations in dedicated hole sections. This new approach can be implemented to release the most challenging stuck pipe mechanisms in drilling to minimize NPT and cost associated with stuck pipe, remedial operations and sidetracks. Similar approach can be utilized to release differentially stuck pipes, tubing and completions. The novelty of this stuck pipe release system is the entire down hole system and operations of the overall system using new approach to generate large shocks down the hole. Additional novelty is related to flexibility during integration and deployment of this system. Similar to current shock tools, this system can be placed in BHA, fishing type assemblies and also pumped down inside of the stuck drill string to save time and cost.


2021 ◽  
Author(s):  
Juntao Yan ◽  
Yongqiang Fu ◽  
Chengfeng Guo ◽  
Jeremy A Greenwood ◽  
Lingjun Wang ◽  
...  

Abstract Sichuan shale gas development will move to reservoirs deeper than 3,500m TVD in the future after a production milestone breakthrough of 10 billion m3 per year from Southern Sichuan basin was achieved. 80% of Sichuan shale gas total resources will come from deep reserves compared to reservoirs at a shallower depth. Improvements in drilling efficiency are the key success factor of deep shale gas development to enhance production and cost control with the increasing activity. Due to complex engineering and geological conditions, drilling deep shale gas horizontal wells in the Southern Sichuan basin is more challenging than traditional shallower wells. The High Pressure and High Temperature (HPHT) harsh drilling environment has caused the frequent failure of the standard Rotary Steerable System (RSS), Measurement While Drilling (MWD), and Logging While Drilling (LWD) tools during recent drilling operations. The surface cooling system, combined with thermal mitigation practices, positively impacted the increasing trend of bottom hole circulating temperature (BHCT) and extended equipment life in short horizontal sections. However, thermal mitigation reduced in effectiveness with the increase in the length of the horizontal section as frictional heating increased. BHCT reached above 150degC while drilling and exceeded the operating limits of standard tools. The challenge of managing the circulating temperatures resulted in approximately 50% of the total runs in 2020 being tripped before the run objectives were met, creating non-production time (NPT) and significantly decreasing drilling efficiency. To overcome this challenge and reduce NPT, two options were evaluated. A high-temperature Motor bottom hole assembly (BHA) brought risks of poor well trajectory control, resulting in well placement issues during geosteering, and lower potential reservoir exposure. For the first time in China Shale gas, an HPHT RSS with near-bit gamma-ray imaging was selected to maximize drilling efficiency and reservoir exposure. In addition to the tool selection, an HT optimization process was created that included horizontal well BHCT modeling and prediction and deep shale gas RSS drilling best practices. The near-bit gamma imaging quality was enhanced to improve steering. These changes delivered record runs in deep shale gas long horizontal wells and significantly decreased NPT. Reducing the reliance on surface cooling systems also increased overall operating efficiency. This paper reviews the choice of equipment, implementation of HPHT RSS, and development of HT optimization process that improved the drilling efficiency, reduced well time and enhanced long horizontal well placement in this complex drilling environment.


2021 ◽  
Author(s):  
Buna Rizal Rachman ◽  
Bonar Noviasta ◽  
Timora Wijayanto ◽  
Ramadhan Yoan Mardiana ◽  
Esa Taufik ◽  
...  

Abstract Achieving a number of well targets in M Area is an important objective for MK, one of the oil and gas operators in Indonesia. An economic challenge is present due to marginal gas reservoirs in shallow zone. The conventional swamp rig unit requires significant costs for site preparation work and in some cases no longer fulfils the economic criteria. The objective was to drill the same one-phase well (OPW) architecture as the swamp rig normally drills, but at lower costs using a hydraulic workover unit (HWU). Drilling the 8½-in hole section OPW architecture using HWU was challenging, not only on the equipment rating and capability, but also on the deck space limitation part. The fit-for-purpose directional and logging-while-drilling (LWD) system was utilized in this project consisting of customized low-torque excellent hydraulics drill bit design, a positive displacement motor (PDM) with aggressive bend setting to achieve directional objective (with max 3.8°/30-m dogleg severity), annular-pressure-while-drilling (APWD) measurement to ensure equivalent circulating density (ECD) is maintained, and combined electromagnetic propagation resistivity and sonic slowness measurement coupled with high-speed telemetry measurement-while-drilling (MWD) tool to get an accurate and timely formation evaluation. The HWU deck space limitation was solved by implementing a single combined directional drilling (DD), MWD, mudlogging cabin, in addition to the remote operation control implementation to further reduce carbon footprint. Five wells were drilled safely and successfully in this campaign. Drilling efficiency improved with up to 109% ROP increase as compared to the first well, showing the progressive learning curve and excellent teamwork from all involved parties. The directional bottom hole assembly (BHA) was capable of delivering up to 4–5°/30-m dogleg, not only achieving the directional objective, but also penetrating the reservoir targets with tight tolerances. The drill bit delivered very good ROP, reaching 60.4 m/h (about 66% of average OPW ROP achieved by swamp rig). This campaign also successfully reduced the overall site preparation cost by up to 30%, enabling MK to drill wells that were initially not feasible to be drilled using swamp rig within the time frame and budget. Thanks to the success, this new method is currently under study for industrialization. The HWU drilling campaign provided a valuable learning experience, is considered as a proven drilling method, and served as a benchmark for other operators in Indonesia. HWU drilling has proven to be an efficient drilling method and capable of delivering the one-phase-well. This paper presents a unique case study of new well open hole drilling with the HWU and its applicability in M Area. Most studies in the past were HWU drilling in re-entry or sidetrack cases.


2021 ◽  
Vol 3 (3) ◽  
pp. 3-10
Author(s):  
B. H. Nugmanov

One of the ways to increase well oil production is to reduce the filtration resistance of the bottom-hole zone. Along with well-known stimulation methods, such as modern methods of treating wells bottom-hole zone, side tracking (drilling of lateral horizontal boreholes) is of great interest. The following works have been implemented Kalamkas field: a complex of geological, geophysical and field exploration; correlation schemes to track the lithology of the formation; clarifying structural maps and engineering maps; justifying activities to select one or more wells for horizontal drilling; hydrodynamic calculations and estimating their flow rate.


2021 ◽  
Vol 9 ◽  
Author(s):  
Deyang Liang ◽  
Zhichuan Guan ◽  
Yuqiang Xu ◽  
Yongwang Liu

Using various tools to obtain downhole data to reach a precise pore pressure model is an important means to predict overpressure. Most downhole tools are connected to the lower end of drill string and move with it. It is necessary to understand the motion state and dynamic characteristics of drill string, which will affect the use of downhole tools. In this paper, a drilling process considering rock-breaking process in vertical wells is simulated using finite element method. In the simulation, gravity is applied to the whole drill string. The contact force between PDC bit and formation is the weight on bit (WOB). And a rotation speed is applied to the upper end of drill string. Analysis of the results shows that the vibration amplitude of bottom hole WOB (contact force between PDC bit and formation, which is the real WOB in drilling process) is bigger than the amplitude of wellhead WOB (acquired through conversion using Hook load, which is on behalf of the WOB obtained on drilling site). Both wellhead WOB and bottom hole WOB decline with a fluctuation in drilling process. In small initial WOB and low rotation speed conditions, the fluctuation of wellhead WOB focuses on low frequency, the fluctuation of bottom hole WOB focus on high frequency, and the phase of them are not identical. In large initial WOB and high rotation speed conditions, the fluctuation of wellhead WOB and bottom hole WOB both become more irregular. As for wellhead torque and bottom hole torque, the fluctuation of them mainly focuses on low frequency. And in high rotation speed conditions, wellhead torque may become negative. The research results are beneficial to the usage of downhole tools.


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