First Abu Dhabi 9.625in × 12.25in Non-Directional Casing While Drilling CWD Run for Intermediate Hole Section Saves Two Days Rig Time, Enhancing Drilling Efficiency & Improving Well Integrity

2021 ◽  
Author(s):  
Felix Leonardo Castillo ◽  
Roswall Enrique Bethancourt ◽  
Mohammed Sarhan ◽  
Abd Al Sayfi ◽  
Imad Al Hamlawi ◽  
...  

Abstract Significant mud losses during drilling often compromises well integrity whenever sustainable annular pressure (SAP), is observed due to poor cement integrity around 9-5/8-in casing in wells requiring gas lift completion. Heavy Casing Design (HCD) is applied as a solution; whereby, two casing strings are used to isolate the aquifers and loss zones, thus ensuring improved cement integrity around the 9 5/8-in intermediate casing. Casing While Drilling (CWD) is a potential solution to mitigate mud losses and wellbore instability enabling an optimized alternative to HCD by ensuring well integrity is maintained while reducing well construction cost. This paper details the first 12 ¼-in × 9-5/8-in non-directional CWD trial accomplished in Abu Dhabi onshore The Non-Directional CWD Technology was tested in a vertical intermediate hole section of a modified heavy casing design (MHCD) aimed at reducing well construction cost over heavy casing design (HCD) as shown in the figure 1. A drillable alloy bit with an optimized polycrystalline diamond cutters (PDC) cutting structure was used to drill with casing through a multi-formation interval with varying hardness and mechanical properties. Drilling dynamics, hydraulics and casing centralization analysis were performed to evaluate the directional tendency of the drill string along with the optimum drilling parameters to address the losses scenario, hole cleaning, vibration, and maximum surface torque. The CWD operation was completed in a single run with zero quality, health, safety, and environment (HSE) events and minimum exposure of personal to manual handling of heavy tubulars. Exceptional cement bonding was observed around the 9 5/8 in casing indicative of good hole quality despite running a significant number of centralizers (with smaller diameter), compared with the conventional drilled wells (cement bond logging was done after the section). CWD implementation saved two days of rig operations time relative to the average of the offset wells with the same casing design. The rate of Penetration (ROP) was slightly lower than the conventional drilling ROP in this application. The cost savings are mainly attributed to the elimination of casing-running flat time and Non-Productive Time (NPT) associated with clearing tight spots, BHA pack-off, wiper trips. The application of CWD in the MHCD wells deliver an estimated saving of USD 0.8MM in well construction cost per well compared to the HCD well design. Additional performance optimization opportunities have been identified for implementation in future applications. The combination of the MHCD and CWD technology enhances cementing quality across heavy loss zones translating into improved well integrity. Implementing this technology on MHCD wells could potentially save up to USD 200MM (considering 250 wells drilled). This is the first application of the technology in Abu Dhabi and brings key learning for future enhancement of drilling efficiency. The CWD technology has potential to enhance the wellbore construction process, which are typically impacted by either circulation losses and wellbore instability issues or a combination of both, it can applied to most of the offshore and onshore fields in Abu Dhabi.

2021 ◽  
Author(s):  
Roswall Enrique Bethancourt ◽  
Mohammed Sarhan ◽  
Felix Leonardo Castillo ◽  
Imad Al Hamlawi ◽  
Luis Ramon Baptista ◽  
...  

Abstract Loss of circulation while drilling the surface holes has become the main challenge in the Abu Dhabi Onshore developed fields. Typical consequences of losses are blind drilling and high instability of the wellbore that eventually led to hole collapse, drill string pack-offs and other associated well-integrity risks. Expensive operations including implementing aerated drilling technique, high water consumption and logistical constraints lead to difficulties reaching planned depth and running casing with added complexities of well integrity due to poor cement quality and bonding in the required isolation zones. Casing while drilling (CWD) is becoming a powerful method in mitigating both lost circulation as well as wellbore stability issues. This paper details the first 13 3/8″ × 16″ successful non-directional CWD trial accomplished in Abu Dhabi and the various advantages of the process. The Non-Directional CWD technology is used to drill vertical or tangent profiles with no directional drilling or logging (formation evaluation) requirements. The casing string is run with drillable body polycrystalline diamond cutters (PDC) bit and solid body centralizers are installed into the casing to achieve the required stand-off for cementing purpose. Some of the best practices applied to conventional drilling operations are not valid for CWD. The paper presents the methodology followed by the drilling engineers during the planning and preparation phases and presents a detailed description of the execution at the rig and the results of the evaluation including time savings, cement quality, rate of penetration, bottomhole assembly (BHA) directional tendency and losses comparison among others.The implementation of CWD saved the operator five days. The bit selection and fit-for-purpose bit design were critical factors for the success of the application. The interval was drilled (as planned) in one run through interbedded formations with a competitive rate of penetration (ROP). In this trial the interval consisted of 2,470ft with an average on-bottom ROP of 63.7 ft/hr, zero quality, health, safety and environmental (QHSE) incidents with enhanced safety for the rig crew.The technology eliminated the non-productive time (NPT) associated with tight spots, BHA pack-off, vibrations or stalls which it is an indication of good hole cleaning and optimum drilling parameters.Medium losses (10-15 BBL/hr) were cured due to the plastering and wellbore strengthening effect of CWD allowing drilling to resume with full returns.Well Verticality maintained with 0.3 degrees Inclination at section final depth.The drillable CWD bit was drilled out with a standard 12.25-in PDC bit in 1 hour as per the plan.


2021 ◽  
Author(s):  
Abdulaziz Al-Qasim ◽  
Sharidah Alabduh ◽  
Muhannad Alabdullateef ◽  
Mutaz Alsubhi

Abstract Fiber-optic sensing (FOS) technology is gradually becoming a pervasive tool in the monitoring and surveillance toolkit for reservoir engineers. Traditionally, sensing with fiber optic technology in the form of distributed temperature sensing (DTS) or distributed acoustic sensing (DAS), and most recently distributed strain sensing (DSS), distributed flow sensing (DFS) and distributed pressure sensing (DPS) were done with the fiber being permanently clamped either behind the casing or production tubing. Distributed chemical sensing (DCS) is still in the development phase. The emergence of the composite carbon-rod (CCR) system that can be easily deployed in and out of a well, similar to wireline logging, has opened up a vista of possibilities to obtain many FOS measurements in any well without prior fiber-optic installation. Currently, combinations of distributed FOS data are being used for injection management, well integrity monitoring, well stimulation and production performance optimization, thermal recovery management, etc. Is it possible to integrate many of the distributed FOS measurements in the CCR or a hybrid combination with wireline to obtain multiple measurements with one FOS cable? Each one of FOS has its own use to get certain data, or combination of FOS can be used to make a further interpretation. This paper reviews the state of the art of the FOS technology and the gamut of current different applications of FOS data in the oil and gas (upstream) industry. We present some results of traditional FOS measurements for well integrity monitoring, assessing production and injection flow profile, cross flow behind casing, etc. We propose some nontraditional applications of the technology and suggest a few ways through. Which the technology can be deployed for obtaining some key reservoir description and dynamics data for reservoir performance optimization.


2021 ◽  
Author(s):  
Hajar Ali Abdulla Al Shehhi ◽  
Bondan Bernadi ◽  
Alia Belal Zuwaid Belal Al Shamsi ◽  
Shamma Jasem Al Hammadi ◽  
Fatima Omar Alawadhi ◽  
...  

Abstract Reservoir X is a marginal tight gas condensate reservoir located in Abu Dhabi with permeability of less than 0.05 mD. The field was conventionally developed with a few single horizontal wells, though sharp production decline was observed due to rapid pressure depletion. This study investigates the impact of converting the existing single horizontal wells into single long horizontal, dual laterals, triple laterals, fishbone design and hydraulic fracturing in improving well productivity. The existing wells design modifications were planned using a near reservoir simulator. The study evaluated the impact of length, trajectory, number of laterals and perforation intervals. For Single, dual, and triple lateral wells, additional simulation study with hydraulic fracturing was carried out. To evaluate and obtain effective comparisons, sector models with LGR was built to improve the simulation accuracy in areas near the wellbore. The study conducted a detailed investigation into the impact of various well designs on the well productivity. It was observed that maximizing the reservoir contact and targeting areas with high gas saturation led to significant increase in the well productivity. The simulation results revealed that longer laterals led to higher gas production rates. Dual lateral wells showed improved productivity when compared to single lateral wells. This incremental gain in the production was attributed to increased contact with the reservoir. The triple lateral well design yielded higher productivity compared to single and dual lateral wells. Hydraulic fracturing for single, dual, and triple lateral wells showed significant improvement in the gas production rates and reduced condensate banking near the wellbore. A detailed investigation into the fishbone design was carried out, this involved running sensitivity runs by varying the number of branches. Fishbone design showed considerable increment in production when compared to other well designs This paper demonstrates that increasing the reservoir contact and targeting specific areas of the reservoir with high gas saturation can lead to significant increase in the well productivity. The study also reveals that having longer and multiple laterals in the well leads to higher production rates. Hydraulic fracturing led to higher production gains. Fishbone well design with its multiple branches showed the most production again when compared to other well designs.


2021 ◽  
Author(s):  
Louis Frederic Antoine Champain ◽  
Syed Zahoor Ullah ◽  
Alexey Ruzhnikov

Abstract Drilling and completion of the surface and intermediate sections in some fields is extremely challenging due to wellbore instability, especially accomplished with complete losses. Such circumstances lead to several time-consuming stuck pipe events, when existing standard ways of drilling did not lead to a permanent resolution of the problems. After exhausting the available conventional techniques without sustainable success, unorthodox solutions were required to justify the well delivery time and cost. Here comes the Casing While Drilling (CwD), being the most time and cost-effective solution to wellbore instability. CwD is introduced at full throttle aiming at the well cost reduction and well quality improvement. The implementation plan was divided in three phases. The first phase was a remedial solution to surface and intermediate sections drilling and casing off to prevent stuck pipe events and provide smooth well delivery performances. After successful implementation of CwD first phase, CwD was taken to the next level by shifting it from a mitigation to an optimization measure. Each step of CwD shoe-to-shoe operations was analysed to improve its performances: drill-out (D/O) of 18⅝-in shoe track with CwD, optimum drilling parameters per formation and CwD bit design. Implemented in 19 wells, CwD shoe-to-shoe performances have been brought up or even above standard rotary bottom hole assembly (BHA) benchmark. Planning for third phase is undergoing whereby CwD is aiming to optimize a well construction to reduce well delivery time, by combining surface and intermediate sections thus eliminating one casing string. Numerous challenges are being worked on including open hole (OH) isolation packer which conform to and seal with the borehole uneven surface. Special "for purpose built" expandable steel packer and stage tool have been manufactured and qualified for the specific application. A candidate well has been chosen and agreed for first trial. The key areas of improvement include, drilling and casing off the surface and intermediate sections while competing with standard rotary BHA performances and slimming down the well profile towards tremendous time and costs savings. This paper encompasses details of constructions of various wells with sufficient contingencies to combat any expected hole problems without compromising the well quality while keeping the well within budget and planned time. It also provides an analysis of the well trials that were executed during the implementation of first and second phases of CwD implementation and the captured lessons learnt which are being carried forward to the next phase. This paper provides the technique on how CwD can be used to help with three aspects of drilling, successfully mitigating holes problems by reducing OH exposure time and to eliminate drill string tripping and modifying conventional casing design to reduce well time and cost by eliminating one casing string.


Author(s):  
Nediljka Gaurina-Medjimurec ◽  
Borivoje Pasic

Exploration and production as one of the most important parts of the petroleum industry encounters different problems, usually resulting in nonproductive time and additional expenses. The most common and most expensive of them are related to wellbore instability and associated problems. Wellbore instability problems are usually related to drilling operation, but they can also appear during completion, workover, or the production stage of a certain well. The traditional solution for wellbore instability problems is composed from the early recognition of specific wellbore instability problems, the main cause identification and swift response. For more effective solution it is necessary to incorporate wellbore stability and risk assessment in the early phase of well design. This chapter gives one general overview of wellbore instability problems and their causes as well as an overview of actual approaches and methods in wellbore stability and risk assessment.


2012 ◽  
Vol 52 (1) ◽  
pp. 261
Author(s):  
Keith Won ◽  
Ming Zo Tan ◽  
I Made Budi Utamain

With the continuous surging in daily rental rates of oilfield exploration rigs, Casing while Drilling technology—which provides operators with an alternative drilling solution for a reduction in drilling flat-time and increased drilling operation efficiency—has appeared to be a standard part of drilling engineers’ toolkit in the well-planning process. Significant cost savings generated by Casing while Drilling have contributed to this technique being widely deployed on top-hole string installations on exploration and appraisal wells in the southeast Asia region. The double-section casing drilling technique has gained increasing popularity among operators in recent years; however, this technique development has been hamstrung by limited casing bit selections. An improved design casing bit has been highly anticipated in the industry to reduce this technique’s complexity of drilling process. Finding an equilibrium between durability and drill-out capability features for a casing bit has been a major challenge for bit designers. The increasing prospect and demand for a double-section casing drilling technique, however, has yielded the development of the casing bit design to a wider portfolio, inclusive of a more robust PDC (polycrystalline diamond compact) cutter-based drillable casing bit. The introduction of the new robust but drillable PDC cutter-based casing bit has broadened the Casing while Drilling application. The double-section casing drilling technique without the need for an additional conventional clean-out trip has become a strong contender to be part of drilling engineers’ next toolkit in delivering enhanced drilling performance and increasing operational efficiencies. This paper will introduce the first case history of the successful planning and implementation of the double-section casing drilling technique—particularly emphasising its optimised drilling performance and ease of drill-out without the need for a specialised drill-out bit.


2021 ◽  
Vol 5 (6) ◽  
pp. 67-71
Author(s):  
Zhongyu Wang

Bridge construction has received a lot of attention as transportation continues to improve. Reinforced concrete linked arch bridges are a common bridge style in today’s bridge construction. This type of bridge not only has a basic and generous shape, but it is also incredibly easy to construct, resulting in significant material and construction cost savings. This article analyzes the construction technology of a reinforced concrete linked arch bridge in order to achieve good construction and application. It is hoped that this analysis can provide a scientific reference for the guarantee of the construction quality and subsequent application effect of this kind of bridge.


1996 ◽  
Vol 36 (1) ◽  
pp. 544
Author(s):  
M.A. Addis ◽  
R.G. Jeffrey

Slimhole drilling is becoming an attractive option as it provides significant cost savings in the petroleum industry. Furthermore, many of the technical obstacles in adapting slimhole drilling for the petroleum industry have been addressed, such as rig modifications, small volume kick detection, drilling fluid design, etc. However, wellbore stability in slimholes is largely taken for granted, when it could potentially increase costs dramatically. In this paper, a review of the available information on the effects of hole size on hole stability is presented. Wellbore stability in holes of different diameters is discussed qualitatively based on published laboratory data and unpublished field data. The quantitative assessment of wellbore instability in slimholes is addressed using observations of instability in a well in which the far field stresses were measured.The field data presented here suggest that slimhole wells are not more stable than conventional wells. The slimhole drilled in NSW shows that even using the most conservative prediction model, wellbore instability would not be predicted—instability was however, observed.


Author(s):  
Shwetank Krishna ◽  
Syahrir Ridha ◽  
Pandian Vasant

Application of machine learning tools in drilling hydrocarbon well is still exploratory in its stage. This chapter presents a brief review of various applied research in drilling operations using machine learning (ML) tools and develop a deep neural network (DNN) model for predicting the downhole pressure surges while tripping. Tripping in or out drill-string/casing with a certain speed from the wellbore will result in downhole pressure surges. These surges could result in well integrity or well control problems, which can be avoided if pressure imbalances are predicted before this operation is engaged. Existing analytical models focus on forecasting the pressure imbalance but requires cumbersome numerical analysis. This could be solved by integrating DNN tool with the best existing analytical model predicted dataset. Consequently, the aim of this chapter is to provide an overview of various applications of machine learning tools in drilling and presenting a step-by-step process of developing a DNN model for the prediction of downhole pressure surges during tripping operation.


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