A Drilling Engineer's Guide to Optimizing Well Design for Wireline Operations

2021 ◽  
Author(s):  
Guy Wheater ◽  
Stuart L. Huyton ◽  
Ronald J. Ford ◽  
Russel Gerrity ◽  
Luke Miller ◽  
...  

Abstract During open-hole wireline operations, at least 95% of cable sticking events are known to be predictable and avoidable. Approximately 40% of these cable sticking events escalate to fishing operations, adding substantial costs to the AFE. Sub-optimal well design, from a wireline acquisition perspective, is known to contribute to such sticking. This paper offers practical guidance for drilling engineers on how their well designs may impact wireline conveyance and sticking risks and what measures they can take at both the design and execution stages to ensure a safe and efficient wireline logging job.


2021 ◽  
Author(s):  
André Alonso Fernandes ◽  
Eduardo Schnitzler ◽  
Fabio Fabri ◽  
Leandro Grabarski ◽  
Marcos Vinicius Barreto Malfitani ◽  
...  

Abstract This is a case study of a presalt well that required the use of 3 different MPD techniques to achieve its goals. The well was temporary abandoned when conventional techniques failed to reach the final depth. Total fluid losses in the reservoir section required changing the well design and its completion architecture. The new open hole intelligent completion design had to be used to deliver the selective completion in this challenging scenario. From the hundreds of wells drilled in the Santos basin presalt, there are some wells with tight or no operational drilling window. In order to drill these wells different MPD techniques are used. In most cases, the use of Surface Backpressure (SBP) technique is suitable for drilling the wells to its final depth. For the more complex cases, when higher fluid loss rates occur, the use of SBP and Pressurized Mud Cap Drilling (PMCD) enables the achievement of the drilling and completion objectives. After the temporary abandonment of this specific well in 2018, the uncertainty of the pore pressure could not ensure that the SBP and PMCD techniques would be applicable when reentering the well. To avoid difficult loss control operations, the completion team changed the intelligent completion design to include a separated lower completion, enabling its installation with the MPD system. Besides the previously used MPD techniques, the integrated final project considered an additional technique, Floating Mud Cap Drilling (FMCD), as one of the possible contingencies for the drilling and completion phases. Well reentry and drilling of the remaining reservoir section included the use all the previously mentioned MPD techniques (SBP, PMCD and FMCD). The lower completion deployment utilized the FMCD technique to isolate the formation quickly and efficiently, without damaging the reservoir. The planning and execution of the well faced additional difficulties due to the worldwide pandemic and personnel restrictions. The success from the operation was complete with no safety related events and within the planned budget. At the end, the execution team delivered a highly productive well with an intelligent completion system fully functional, through an integrated and comprehensive approach. MPD use on deepwater wells is relatively new. Different operators used several approaches and MPD techniques to ensure safety and success during wells constructions over the last decade. This paper demonstrates the evolution of MPD techniques usage on deepwater wells.



2021 ◽  
Author(s):  
M Hatta M Yusof ◽  
Rahimah A Halim ◽  
Nurfaridah Ahmad Fauzi ◽  
Ahgheelan Sella Thurai ◽  
M Zulfarid Khalid ◽  
...  

Abstract 2020 marks another challenging year for O&G sector, with the operators being in an uphill battle to survive the plunging oil price. With CAPEX rationalization underway, future field development may only be prospective via implementation of low-cost Field Development Plan (FDP). As well cost is a significant component of development CAPEX, low well cost must be pursued, by designing fit-for-purpose wells. For relatively shallow (≈2000 m-MD in meterage drilled) wells, a simple well design consisting of only two-hole sections (excluding Conductor) shall be considered. This design approach though, may require the Surface Casing to also be the Production Casing (if only Production Liner will be ran in the production hole section or if open hole completion is feasible or if cemented monobore completion strategy is adopted). This aspect of casing design (having Surface cum Production Casing) does indeed pose well integrity concerns as the quality of cement behind the Surface cum Production Casing is uncompromisable to ensure no gas can breach to surface. This paper discusses the design measures than can be incorporated into the well trajectory, cementing plan, and production surveillance in order to support the feasibility of Surface cum Production Casing concept.



2021 ◽  
Author(s):  
Anna Shakhova ◽  
Natalia Lisyutina ◽  
Irina Lebedeva ◽  
Oleg Valshin ◽  
Roman Savinov ◽  
...  

Abstract This paper provides the results that were achieved and shares the drilling unique practices that were implemented to deliver the first complex bilateral extended reach drilling (ERD) well in Odoptu-more field (North Dome). Well design driven by geological objectives considered drilling 215.9mm main and pilot holes (PH). Well complexity was governed by the type of a profile having ERD ratio of 5.22 (main hole) / 4.60 (PH) and trajectory's 3D nature (turn in azimuth of 90 degrees) compared to previous wells in the project drilled mainly with 2D profiles. Apart from the problems connected with drilling and casing upper sections key challenges comprised kicking off in 215.9mm open hole at 5955m MD and 1512m TVD with rotary steerable system, setting cement plugs at shallow true vertical depth (TVD) at 89 degrees of inclination to abandon laterally drilled PH, delivering 168.3mm production liner to bottom with a risk of entering a lateral while running in hole. An effective collaboration between integrated engineering team and customer departments went far beyond ERD standard set of operations already existing in the project thus allowing to break its own records and to set new achievements due to integrated technological approach. The longest 444.5mm section (2975 m) was drilled in one run achieving the record daily drilling rate and rate of penetration (ROP). Cementing of 244.5mm floated liner resulted in the highest good cement bond integrity percentage ever achieved among other wells in project due to new ways of casing standoff and fluid rheology hierarchy modeling. For the first time in the project 215.9mm main horizontal hole in extreme reach ERD well has been drilled by kicking off in open hole from the pilot horizontal one with push-the-bit rotary steerable system without a kickoff plug with pilot hole being abandoned by setting cement plugs. Project-specific risk assessment conducted by team allowed successful deployment of 168.3mm liner into the main hole. Moreover, due to thorough engineering planning electrical submersible pump (ESP) was run without extending 244.5mm liner to surface by tie-back thus saving additional 7 days. Drilling first bilateral ERD well unlocked opportunities for the operator to reach, explore and develop different extended geological targets thus eliminating well construction process of additional wells on drilling upper sections.



2021 ◽  
Author(s):  
Aaron C Hammer ◽  
Tom D Gonzalez ◽  
Herb P Dhuet ◽  
Hege Andresen ◽  
Siv Merete M Sunde ◽  
...  

Abstract The Troll Phase 3 (TP3) wells were designed to enable high gas rates and sand free production for an expected lifetime of 40 years with a minimum pressure drop. By taking reservoir and production properties into account, open-hole gravel pack (GP) sand screens in the lower completion and big bore tubing in the upper completion were selected. To further reduce the pressure loss in the well, reduce rig time and cost, and reduce deployment risks, eliminating the intermediate completion was proposed. Traditionally, an intermediate completion is required to serve as a gas-tight barrier for running of the upper completion, mainly due to historical limitations of the GP extension (GP sleeve) not being a barrier qualified to API 19AC Validation grade V0 (referred to as V0 hereafter) after pumping sand slurry through it (post-erosion). An extensive qualification program was completed to qualify the GP system to API 11D1 and API 19AC V0 for use as a gas-tight barrier post-erosion. This allows the GP system to serve as a primary barrier while installing the upper completion and temporarily abandoning the well. The GP packer was qualified to API 11D1 V0 with the additional requirement to perform entire qualification in as-rolled casing and including a plug-in-tailpipe load case. The GP sleeve provided the most technically challenging requirements: a full-scale erosion test, immediate closure of the sleeve after pumping operation, followed by API 19AC Annex A V0 validation. Challenges were encountered trying to meet the rigorous V0 (zero bubble) acceptance criteria post-erosion. A significantly different approach was developed to achieve gas-tight performance in debris-laden environments. The new design successfully passed the post-erosion API 19AC V0 qualification to the full rating of the GP sleeve. The GP system development and qualification enabled the industry-first V0 post-erosion GP system for Equinor, which eliminates the need for an intermediate completion. This state-of-the-art gravel pack system enabled the simplified high gas rate, big-bore well design, not previously possible given well barrier considerations. The reduced pressure drop across the lower completion is expected to yield a higher gas production rate for the 40 years expected well life, contributing significant value to the TP3 project.



2021 ◽  
Vol 54 (2F) ◽  
pp. 48-61
Author(s):  
Walaa Khyrie ◽  
Ayad Alrazzaq

The oil and gas industry, wellbore instability plays an important role in financial losses and stops the operations while the drilling which leads to extra time known as non-productive time. In this work, a comprehensive study was carried out to realize the nature of the instability problems of the wellbore in Rumaila oilfield to improve the well design. The study goal is to develop a geomechanical model in one dimension by utilizing Schlumberger Techlog (Version 2015) software. Open hole wireline measurements were needed to develop the model. The model calibrating and validating with core laboratory tests (triaxial test), well test (Mini-frac test), repeated formation test. Mohr-Coulomb, Mogi-Coulomb, and Modified Lade are the three failure criteria which utilized to analyze the borehole breakouts and to determine the minimum mud weight needed for a stable wellbore wall. For more accuracy of the geomechanical model, the predicted profile of the borehole instability is compared with the actual failure of the borehole that is recorded by caliper log. The results of the analysis showed that the Mogi-Coulomb criteria are closer to the true well failure compared with the other two criteria and considered as the better criteria in predicting the rock failure in the Rumaila oilfield. The wellbore instability analysis revealed that the vertical and low deviated wells (less than 40º) is safer and more stable. While, the horizontal and directional wells should be drilled longitudinally to the direction of the minimum horizontal stresses at a range between 140º–150º North West-South East and the mud weight recommended is increased to 10.5 ppg to avoid most of instabilities problems. The results contribute in development plan of the wells nearby the studied area and decreasing NPT and cost.



2016 ◽  
Author(s):  
Hung Vu ◽  
Son Tran ◽  
Trang Nguyen ◽  
Bharathwaj Kannan ◽  
Khoa Tran ◽  
...  

ABSTRACT Application of openhole sand control technology is becoming mandatory in the field, particularly with the given uncertainty in geomechanics, challenges to wellbore integrity while drilling, and sand production during the life of the well. The completion equipment readiness and success of the installation can be challenging in the event of extending the horizontal section to accommodate geological heterogeneity and maximizing well productivity. This paper discusses operational excellence recorded in Well A, in the Thang Long Field, offshore Vietnam, from well design perspectives ensuring maximum reservoir contact to outcome of well completion. The well was targeted in the Oligocene reservoir, a thin oil rim with large gas cap overlay, and required drilling and completion for 1126 m horizontal length of 8 1/2-in. open hole. The completion design included multiple swellable packers for isolation of unwanted zones, 6 5/8-in. basepipe sand screens for the production zones, and a fluid loss control device to help prevent undesirable losses. Several torque and drag simulations were performed to help predict potential threats that could be encountered during completion string deployment or during space out of the inner wash pipe string. One apparent challenge of this completion design was to deploy the lower completion string to total depth (TD) per stringent reservoir requirements, resulting in an approximate 1126 m length of the string in the horizontal section. Another task was to facilitate manipulating 1130 m of wash pipe inside the completion string to locate the seal assemblies accurately at the corresponding seal bore extension positions for effective acidizing treatment. Although these were long sections of completion string and wash pipe, the quality of acidizing stimulation to effectively remove mud cake should not be compromised to ensure positive production rates. During operations, the completion string was run to target depth without any issue, and the wash pipe was spaced out and manipulated correctly. These operations subsequently led to a successful acidizing treatment and the proper closure of the flapper type fluid loss device. The completion design and operation were concluded successfully, significantly contributing to field production performance to date. The novelty of the completion design and installation is the ability to deploy an 1126-m lower completion in long, highly deviated and horizontal openhole section coupled with acid stimulation in reasonable time and as per plan.



2021 ◽  
Author(s):  
Thien Yu Loh ◽  
Anh Tuan Duong ◽  
Woon Phin Chong

Abstract Monobore cementation is defined as where a single production tubing size runs from the pay zone all the way to surface and is cemented in place. This type of well design greatly reduce rig time and cost. The challenge however is to achieve a good cement in the annulus as a well barrier and to have a clean internal tubing after the cementing job to allow for successful production of the well. To achieve a clean internal tubing, a distinct bottom and top plugs were used as a means of mechanical separation. For fluids design, mud had to be thinned down prior to the cementing job and, a designed fiber based spacer system was used to physically scrub any mud-film sticking on the tubing walls. The centralizers and cement system were designed to allow for efficient displacement of mud and hence providing good overall placement and top of cement in the tubing-casing annulus. The cement in the annulus will be verified by pressure testing the annulus to 500 psi higher than previous shoe leak-off. This approach was implemented for the campaign of six wells, all designed with 5-1/2in monobore tubing. The bottomhole static temperature (BHST) of the well ranges from 300 to 350°F. The cementing system also had to be designed to cater to the challenge of this field, having CO2 as high as 60%, high temperatures, and a long open hole section that requires isolation and cement to set within a required timeframe. The cementing jobs were validated by no losses or gains during the job, floats holding at the end of the cementing job, differential pressure of cement prior to bumping the plug, density and pump rates executed as planned, accepted pressure test criteria of the annulus, output validation of cement contamination in pipe and annulus based on fluids and final well information. To further validate this system, the cement bond log was also run as part of the evaluation process and the cement log showed that zonal isolation was achieved. After the perforations, the perforation tool was pulled out to surface and the tool looked very clean with no signs of contaminated mud or cement around the tool. We demonstrate how this unique cementing approach can be a solution for the challenges of monobore cementing and one of the biggest problems of monobore cementing in the industry.



2019 ◽  
Vol 59 (2) ◽  
pp. 814
Author(s):  
Andrew Sellars ◽  
Thivanka Dedigama ◽  
Mohammad Zaman

Santos’ Roma field, located in the Surat Basin, has been producing coal seam gas (CSG) since 1988; however, development drilling did not commence until 2011. Since this time, well design has evolved to maximise access to coals and operability for artificial lift systems. Concurrently, performance has dramatically improved through scale of sanctioned work programs and revised contracting strategies, enabling continuous and sustainable time and cost reductions. This paper reviews Santos’ development drilling activity in the Roma CSG field since 2011, highlighting critical events and step changes. The following aspects are addressed: • Evolution of well design: A series of well designs have been trialled, ranging from deviated to vertical, fracture stimulated to open-hole slotted liner well types. Collaboration with both Reservoir Engineering and Production Operations have been critical in arriving at a fit-for-purpose design. • Effect of the industry downturn: The industry downturn spanning 2014–2016 presented an opportunity to reset and rationalise execution approach. • Operating and contracting model: The updated model focused on utilising a consistent, fit-for-purpose rig fleet and service companies, supported by lean office and field based operations teams. • Benefits of large scale, continuous work programs: The scale and continuity of operations are key to achieving continuous and sustainable time and cost reductions. • Opportunities: Future opportunities have been identified for ongoing optimisation in a changing market.



2021 ◽  
Author(s):  
Eduardo Schnitzler ◽  
Luciano Ferreira Gonçalez ◽  
Roger Savoldi Roman ◽  
Marcello Marques ◽  
Fábio Rosas Gutterres ◽  
...  

Abstract This paper describes the challenges faced on the deployment of intelligent well completion (IWC) systems in some of the wells built in Buzios field, mostly related to heavy fluid losses that occurred during the well construction. It also presents the solutions used to overcome them. This kind of event affects not only drilling and casing cementing operations, but may also prevent a safe and efficient installation of the completion system as initially designed. The IWC design typically used in Brazilian pre-salt areas comprises cased hole wells. Perforation operations must be performed before installing the integral completion system, as it does not include a separation between upper and lower completion. Therefore, the reservoir remains communicated to the wellbore during the whole completion installation process, frequently requiring prior fluid loss control as to allow safe deployment. Rock characteristics found in this field make it difficult to effectively control losses in some of the wells, requiring the use of different well construction practices that led to the development of some new well designs. The well engineering team developed a new well concept, where a separated lower completion system is installed in open hole, delivering temporary reservoir isolation. This new well architecture not only delivers reduced drilling and completion duration and costs, but also provides the IWC features in wells with major fluid losses. This is possible by the use of multiple managed pressure drilling (MPD) techniques when required, which were considered since the initial design phase. Safe and effective construction of some wells in pre-salt fields was considered not feasible before the adoption of MPD solutions, both for drilling and completions. Other important aspects considered on the new well design are the large thickness and high productivity of Buzios field reservoirs, as well as the need of some flexibility to deal with uncertainties. Finally, the new completion project was also designed to improve performance and safety on future challenging heavy workover interventions. The well construction area has gradually obtained improved performance in Buzios field with the adoption of the new practices and well design presented in this paper. The new solutions developed for Buzios field have set a new drilling and completion philosophy for pre-salt wells, setting the grounds for future projects. The improved performance is essential to keep these deepwater projects competitive, especially in challenging oil price scenarios. One of the groundbreaking solutions used is the possibility of installing the lower completion using managed pressure drilling techniques.



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