bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exceeding Technical Limit for Drilling and Completing Complex Wells by using an Optimized Flat-Rheology Mud Formulation: A Comprehensive Overview
Authors: Alomair Abdullah Abdulaziz , Cuellar Hugo Fernando , Kashwaa Mohamed , Sharma Sunil 
Published: May 2021

Abstract
Horizontal sections drilled in conditions that require high mud densities to prevent wellbore collapse are very challenging from both drilling engineering and drilling fluid management point of views. Due to drilling complications, nonaqueous fluids (NAFs) are the best suitable drilling fluids of choice for drilling complex and long horizontal sections. From the other side, as nonacid soluble weighting materials cannot be used while drilling some reservoir sections, which are completed with open screens in open hole, using calcium carbonate is the most economical and best preferred acid soluble/nondamaging option to formulate these fluids.
When the density requirements reach above 90 lb/ft3 (12 lb/gal) while using calcium carbonate in the NAFs, fluid formulations exhibit high rheological values due to excessive solids. High solids loading and improper fluids engineering in these high-density ranges lead to hole instability and differential sticking issues in addition to extreme difficulties in managing completions screens runs. These challenges can severely limit the well depth or increase the operation time, impacting profitability of whole project; failing to tackle even one of them could result in catastrophic failure.
To overcome above associated challenges, a flexible novel flat rheology invert emulsion system formulation was introduced, which was customized for sustaining high solids loading while maintaining its signature flat-rheology profile. This system uses new technology emulsifier and rheology modifier package for achieving flat-rheology independent of temperature and pressure changes. The fluid formulation was implemented in the area by loading the mud system with more than 330 pounds per barrel of calcium carbonate for reaching densities up to 99 lb/ft3 (13.25 lb/gal).
This paper will present a comprehensive overview of novel technology, the steps taken from planning to execution, the overall performance-based results, the cost effectiveness of the new solution, and the challenges during implementation. The troubleshooting steps taken are also discussed for all the challenges that occurred while drilling.
Temporary Isolation of a Prolific Open Hole Gas Zone using a Non-Damaging Methodology - A Multi-Well Case Study in a Field of Kurdistan N. Iraq
Authors: Looten Kristopher A , Raza Mustansar 
Published: May 2021

Abstract

Objectives/Scope
A case study is presented detailing the methodology used to place a non-damaging temporary isolation barrier in a group of naturally fractured, prolific gas wells in a field in Kurdistan. The temporary isolation facilitated removal of the original completion string and installation of the redesign. Wells were returned to production with-out the need to stimulate proving success of the non-damaging methodology employed.

Methods, Procedures, Process
The operator had 4 wells with OH sections ranging from 33-181m which were completed in the 1980’s - 1990's with no production packer. In order to preserve well bore integrity the completion string needed to be pulled and replaced by a string with production packer and DH gauges. A procedure was developed to fill the highly fractured OH with a mixed particle size CaCO3 carried into the wellbore by a non-damaging surfactant based gel. Caliper logs were not available and the presence of natural fractures posed a challenge to calculating the actual OH volume. A system was developed to carry the CaCO3 into the wellbore in stages and slickline was employed to measure fill after each stage. Once the OH was filled with CaCO3 and well would support a fluid column coil tubing was used to place an acid soluble cement plug in the short interval between casing shoe and end of tubing (8-10m)

Results, Observations, Conclusions
The first well in the campaign required more than 10 times the theoretical volume of CaCO3 to fill the open hole. It was concluded the surfactant gel was likely carrying the CaCO3 into the fractures. The procedure was modified to tie in a line of breaker solution to the well head allowing sufficient viscosity of the fluid to carry the CaCO3 from surface but immediately lose viscosity and allow the CaCO3 to settle in the wellbore without being carried into the formation. Specific coil tubing procedures were employed to allow the setting of ultra-short acid soluble cement plugs (&lt;10m). All wells were successfully isolated to allow the safe workover of the completion string and returned to production with no loss of gas flow, with-out the need to stimulate after the work over.

Novel/Additive Information
The campaign exhibited a new method of employing existing technologies to achieve the objective in a highly challenging and relatively new oilfield of Kurdistan. The campaign also demonstrated the benefit of the operator and service company closely collaborating on each step of a novel process. The workovers would not have been successful with-out the close collaboration of the two companies.
Lean Rig-Less and Explosiveness Abandoning in Morocco
Authors: Baumgardner Lonny , Ahamiri Jamal , Kuyken Chris , Farouk Mohamed , Jammeli Kamel , Merchan Ylmer 
Published: May 2021

Abstract
A 5-well rig-less & explosiveness abandonment campaign by 2 project partners operator and service provider was made a reality in Morocco whereby a novel method of cementing squeeze of perforations and an annular fill-up were established in one single operation.
This is called LEAN abandonment and the method was masterminded as a result of intense collaboration between both partners. The method is scale-able and has full merit to target existing legacy wells for abandonment in Morocco and world-wide where appropriate.
In this LEAN approach the tubing and annulus were communicating via SSD / non-explosive created tubing punch by holding backpressure on the annulus till perforations squeezed or pressure lock-up and subsequently immediately opening the annulus and releasing the annular pressure whilst continuing pumping and filling the annulus with some 800 m of cement creating the firm additional barrier.
Clinical planning by operator and service provider on a establishing a new abandonment process that is opening-up further in-country and beyond opportunities was the critical success factors in this work. It led to organic improvement on a well by well basis in the campaign, it resulted in safe and successful operations and achieving abandonment objectives cementing to surface in tubing and annulus.
LEAN Abandonment forms a paradigm shift. It may be different in different down-hole settings and there is no single solution however like in our case working a bottoms-up approach has resulted the lowest cost solution and having done so ways to improve overall safety and efficiency were identified. The use of non-explosive technology is a very good example.
The Axial Agitation System Effect on Rotary Steerable Drilling: ADNOC Offshore Mature Field Case Study
Authors: Gohel Prashant , Al-Kasasbeh Ameen , Subramanian Meenakshi , Ary Wahyudi , Mohamed Nowfal 
Published: May 2021

Abstract
The drilling industry faces several challenges related to downhole vibration; amongst the solutions introduced to alleviate those challenges, a unique Axial Agitation System is often considered. This paper qualitatively analyses the effect of the Axial Agitation System in directional drilling and quantifies how it addresses the above challenges observed in Rotary Steerable System (RSS) Bottom Hole Assembly (BHA) used in the 8.5 in. section in different wells of the ADNOC Offshore mature field.
The Axial Agitation System consists of Axial Oscillation Tool which generates a pressure pulse from a valve driven by mud flow converted to axial motion by The Shock Tool. The system complements the rotational movement of the string by introducing gentle and consistent axial oscillating motion. The drill string moves around its rotational axis, oscillating along its axial axis reducing kinetic frictional losses from interaction with the wellbore, especially in directional and long lateral sections.
The analysis consisted in comparing drilling dynamics metrics between wells with AAS in the drill string and offset wells without it, in the 8.5in hole section. As a pilot project, the system was introduced into Well A. Based on the successful tests in the pilot well; the system was also utilized in Wells B & C. The metrics include, but are not limited to, drilling activities, surface mechanical indicators, downhole data from the RSS as well as mathematical modelled algorithms. The results of the analysis of wells clearly indicate an enhancement into the drilling dynamics in terms of overall reduction in kinetic friction, improved weight transfer, less hanging and levels of torsional dynamics, shocks and vibration. The collateral benefits also included performance improvement, reduced non-productive time (NPT) and lower mechanical specific energy (MSE) to drill the section. The Axial Agitation System complemented very well with the rotary steerable system as well as other BHA components and delivered consistent performance in all three wells.
High amplitude fine-tuned Axial Agitation System paired with RSS BHA creates a combination of a highly efficient directional system. The results are consistently performance with reduction in the shock and vibration levels in the environment. This also benefits in improving tool reliability, directional control while also optimizing the repair and maintenance costs for the downhole tools.
A Matrix Acidizing System for Controlled Carbonate Well Stimulation using a Carboxylic Acid Salt with a Chelating Agent
Authors: Bokkers Albert , Brandenburg Piter , Lare Coert Van , Kooijman Cees , Schutte Arjan 
Published: May 2021

Abstract
This work presents a matrix acidizing formulation which comprises a salt of monochloroacetic acid giving a delayed acidification and a chelating agent to prevent precipitation of a calcium salt. Results of dissolution capacity, core flood test and corrosion inhibition are presented and are compared to performance of 15 wt% emulsified HCl.
Dissolution capacity tests were performed in a stirred reactor at atmospheric pressure using equimolar amounts of the crushed limestone and dolomites. Four different chelating agents were added to test the calcium ion sequestering power. Corrosion tests were executed using an autoclave reactor under nitrogen atmosphere at 10 barg. Core flood tests were performed to simulate carbonate matrix stimulation using limestone cores.
It was found that the half-life time of the hydrolysis reaction is 77 min at a temperature of 100 °C. Sodium gluconate and the sodium salt of D-glucoheptonic acid were identified to successfully prevent the precipitation of the reaction product calcium glycolate at a temperature of 40 °C. Computed Tomography (CT) scans of the treated cores at optimum injection rate showed a single wormhole formed. At 150 °C an optimum injection rate of 1 ml/min was found which corresponds to a minimum PVBT of 6. In addition, no face dissolution was observed after coreflooding. Furthermore, the corrosion rates of different metallurgies (L80 and J55) were measured which are significantly less than data reported in literature for 15wt% emulsified HCl.
The novelty of this formulation is that it slowly releases an organic acid in the well allowing deeper penetration in the formation and sodium gluconate prevents precipitation of the reaction product. The corrosivity of this formulation is relatively low saving maintenance costs to installations and pipe work. The active ingredient in the formulation is a solid, allowing onsite preparation of the acidizing fluid.
Drilling the Un Drillable: A Case Study of the Bela Well in Makran Accretionary Prism
Authors: Baig Umair Ahmed , Agha Ghulam Nabi 
Published: May 2021

Abstract
The Bela Well is situated on Makran accretionary prism with several active mud volcanoes that makes conventional drilling challenging due to the extremely high pore pressure i.e. in excess of 15,000 psi and a very narrow window between pore pressure and fracture pressure. This adverse condition was observed in the 9 offset wells drilled within this basin with problems related to wellbore instability, lost-circulation zones and over-pressured formations leading to kick/loss well control scenarios that resulted in the well being abandoned prior to reaching the geological target.
The constraint to drill the planned and 8-3/8" section in the well was the unpredictability of the pore/fracture pressure in the Panjgur formation representing a high-level operational risk. Solutions to tackle such a high pressure well included incorporating heavy grade casing i.e. 9-7/8"- 72 ppf in the planning stage, utilization of a 3000 HP rig to cater to extreme axial and hydraulic loads. Whereas MPD was planned as a technique to cater to the narrow window between pore pressure and fracture pressure.
A managed pressure drilling (MPD) system was utilized to enable drilling the 8-3/8" hole section. An MPD system that applies constant bottom hole pressure enabled drilling the section with statically underbalanced mud weight by keeping a constant surface back pressure to prevent any influx. The drilling window for MPD was validated by determining the Bottom Hole Pressure where both, an influx from the formation and fluid losses occurred. These values were later used to establish the target Equivalent Circulating Density-ECD to drill the hole accordingly. Trips for BHA change or BOP test were performed by placing a pressurized mud cap in the wellbore.
This paper describes in detail the successful MPD application resulted in the first well being drilled in the Makran accretionary prism to a depth of 5000 m. Lessons learned and challenges encountered will also be discussed in this paper
Selection of Biopolymers and Lubricants to Mitigate Stabilization of Gas/Air Entrapment in ERD Wells: Offshore Abu Dhabi
Authors: Haddad Mohamed , Alwahedi Khalid Ahmed , Al Hilali Osama Mohamed , Cesetti Maurizio , Benygzer Mhammed , Husien Mohammad , Allogo Clotaire-Marie Eyaa , Cholakkaparamban Naseerali , Barcan Armand , Rasheed Ami 
Published: May 2021

Abstract
The paper will present lessons learnt to mitigate the stabilization of the air/gas entering into lubricious biopolymer water-based system which decreased density of mud while drilling. The system selected for its highly lubricious properties and formation damage free properties to accommodate the usage of resistivity equipment provided excellent results in the field. Performance was almost equivalent to non-aqueous drilling fluid. However, the stabilization of gas/air entering the mud was encountered generating drilling troubles and risk of well control problems.
An extensive study performed, consisted of assessing interactions between components and containments of the mud system with gas/air, crude-oil and drill solids introduced from the reservoir. The testing involved the adding of air from air-compressor for 60-second while mud sample is sheared at 6000 rpm. The mud weights of samples were measured before addition of air, right after and 60-second after the aeration. The percentage of density drop was calculated. Target value was maximum drop of 5% within 60 second after stopping the addition of air. Several combinations of polymers, lubricants, contaminants and other additives were evaluated.
The study demonstrated that the interactions between crude-oil, polymers and lubricants can highly stabilize air/gas entrapment in the biopolymer water base mud system. The phenomena led to significant density decrease, drilling troubles, well control and safety issue in the field. They can also increase the viscosity of the biopolymer mud system. However, highly stabilized air/gas entrapment can be removed by the addition of emulsion breaker at concentration less than 1.5%vol of mud. In addition, the type and nature of the lubricant plays a major role in the stabilization of air/gas entrapment. The selection of the polymers should be combined with the choice of lubricant during the design phase to minimize the gas entrapment.
Knowledge gained from the study establish a new testing protocol to assess in the laboratory the air/gas entrapment close to field shear conditions. The testing protocol showed good correlation with the field. The testing protocol can be used during the design phase or for investigations. It will improve the overall design of mud system where highly lubricious fluid is needed. Combination of polymers and lubricants did also provide low air/gas entrapment tendency.
Application of Resin-Cement Blend to Prevent Pressure Build-Up in Casing to Casing Annulus CCA: A Novel Approach to Improve Well Integrity
Authors: Ali Wajid , Mata Freddy Jose , Hashmi Ahmed Atef , Al-Yami Abdullah Saleh 
Published: May 2021

Abstract
Assurance of well integrity is critical and important throughout the entire well's life cycle. Pressure build-up between cemented casings annuli has been a major challenge all around the world. Cement is the main element that provides isolation and protection for the well. The cause for pressure build-up in most cases is a compromise of cement sheath integrity that allows fluids to migrate through micro-channels from the formation all the way to the surface. These problems prompt cementing technologists to explore new cementing solutions, to achieve reliable long-term zonal isolation in these extreme conditions by elevating shear bond strength along-with minimal shrinkage. The resin-cement system can be regarded as a novel technology to assure long term zonal isolation. This paper presents case histories to support the efficiency and reliability of the resin-cement system to avoid casing to casing annulus (CCA) pressure build-up.
This paper presents lab testing and application of the resin-cement system, where potential high-pressure influx was expected across a water-bearing formation. The resin-cement system was designed to be placed as a tail slurry to provide a better set of mechanical properties in comparison to a conventional slurry. The combined mixture of resin and cement slurry provided all the necessary properties of the desired product. The slurry was batch-mixed to ensure the homogeneity of resin-cement slurry mixture. The cement treatment was performed as designed and met all zonal isolation objectives. Resin-cement’s increased compressive strength, ductility, and enhanced shear bond strength helped to provide a dependable barrier that would help prevent future sustained casing pressure (SCP).
The producing performance of a well depends in great part on a good primary cementing job. The success of achieving zonal isolation, which is the main objective of cementing, is mainly attributed to the cement design. The resin-cement system is evolving as a new solution within the industry, replacing conventional cement in many crucial primary cementing applications. This paper highlights the necessary laboratory testing, field execution procedures, and treatment evaluation methods so that this technology can be a key resource for such operations in the future.
The paper describes the process used to design the resin-cement system and how its application was significant to the success of the jobs. By keeping adequate strength and flexibility, this new cement system mitigates the risk of cement sheath failure throughout the life of well. It provides a long-term well integrity solution for any well exposed to a high-pressure environment.
Liquid Strength Retrogression Control Additive
Authors: Jadhav Rahul , Pisklak Thomas 
Published: May 2021

Abstract
To mitigate strength retrogression at temperatures, higher than 230°F, well cement designs typically include strength retrogression control additives (SRCAs). Solid siliceous materials (e.g., silica flour, fume, and sized-sands) are commonly used SRCAs that are incorporated into cements using dry-blending techniques. This study highlights liquid silica compositions as alternative SRCAs to dry-blended silica for high-temperature cementing. Liquid additives can be managed easily, delivered accurately, and offer a reduced on-site footprint, thus making them particularly advantageous for operations offshore and in remote locations.
This paper presents a study on the use of liquid silica compositions as SRCAs and their effect on cement slurry properties, such as thickening time, mixability, fluid loss, rheology, and free water. The cement slurry used during the current study was prepared and tested according to API RP 10B-2 (2005). The performance of the liquid silica composition was tested at temperatures up to 400°F. Set cement samples were prepared using the liquid silica composition and silica flour, cured for up to 14 days at different temperatures. In addition, permeability testing was also performed on the samples.
This paper presents the findings of this research, including strength and permeability test results on cement blends cured at temperatures of 300, 330, 350, and 400°F. The liquid silica composition, which provided silica to the cement formulation equivalent to 35% BWOC dry silica (48% BWOC liquid SRCA), functioned effectively as an SRCA at temperatures up to 330°F. Signs of strength retrogression were observed at 350°F and were more pronounced at 400°F. A greater concentration of the liquid silica composition may be necessary to prevent strength retrogression at temperatures higher than 330°F. The liquid silica composition also demonstrated mild retardation and a dispersing effect on the slurry. However, it helped enable improved slurry stability and suspension, thus providing improved control over free water without adverse effects on fluid loss and sedimentation.
The study results demonstrate that a liquid SRCA can help improve the performance of annular cement designs to provide dependable barriers and effective zonal isolation during high-temperature cementing applications. The improved performance enabled by this liquid silica composition verifies its potential use as an alternative SRCA for high-temperature oil well cementing operations.