bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reticulated Foam Enhanced High Fluid Loss Squeeze LCM for Severe Lost Circulation Management in Highly Fractured Formations
Authors: Savari Sharath , Rolfson Jonathan , Williams Robert , Whitfill Donald L. , Wang Hong Max 
Published: August 2016

Abstract
Controlling severe to total lost circulation in naturally fractured vugular formations and rubble zones can be challenging. In such situations, conventional lost circulation materials (LCMs) might not be effective, and more difficult applications, such as gunks, reverse gunks, or cement, might fail as well. High fluid loss squeeze (HFLS) applications have been applied with mixed success. A new HFLS LCM containing a unique component has been developed and shows great potential as a dependable solution. This new HFLS LCM also shows potential for sealing induced fractures in shale or other formations of low permeability.
This paper discusses a laboratory investigation of a HFLS LCM to plug slotted discs of various sizes in a permeability plugging apparatus (PPA) test. Follow-up field applications that demonstrate its success are also discussed. The proposed HFLS LCM is a combination of particulates and a unique reticulated foam material that contributes to a rapid dewatering effect. The reticulated foam is the unique component, which forms a bridge on the face of large fractures. The particulates of the composition then plug the foam, forming a thick cake. Recommended practices for mixing and placement of HFLS LCM essential for successful applications are also discussed.
The HFLS LCM application was able to seal slotted discs up to 3000 μm. Supplementing the HFLS LCM with additional larger reticulated foam (medium) enabled the plugging of slotted discs up to 8000 μm. For plugging slotted discs from 8000 to 10 000 μm, the HFLS LCM was supplemented with medium and coarse reticulated foam. This plugging data, covering slotted disc sizes up to 10 mm, is the first of its kind and provides confidence in considering the HFLS LCM as a potential option for severe to total loss situations.
Three applications of HFLS LCM are discussed. The first application manages severe losses (in the range of 180 bbl/hr) in a naturally fractured shale formation in an unconventional reservoir in North America. The second application manages severe losses in naturally fractured, vugular formations in the Asia Pacific region. In both the cases, because high losses were expected, the HFLS LCM was stored on-site as a contingency LCM. As soon as losses were observed, an appropriate volume of the pill containing the HFLS LCM supplemented with additional amounts of reticulated foam LCM was pumped. Losses were cured, and the wells were drilled/cemented successfully.
Real-Time Wellbore Stability Evaluation for Deepwater Drilling During Tripping
Authors: Zhang Feifei , Kang Yongfeng , Wang Zhaoyang , Miska Stefan , Yu Mengjiao , Zamanipour Zahra 
Published: August 2016

Abstract
This paper identifies wellbore stability concerns caused by transient surge and swab pressures during deepwater drilling tripping and reaming operations. Wellbore stability analysis is presented that couples transient surge and swab wellbore pressure oscillations and in-situ stress field oscillations in the near wellbore (NWB) zone in deepwater drilling.
Deepwater drilling is usually subjected to narrow drilling windows and significant wellbore pressure oscillations during tripping/reaming because of well depth. However, integration of transient surge and swab pressure analysis, and its effects on in-situ stress analysis around the wellbore, is rarely industry studied.
A transient surge and swab model is developed by considering drillstring components, wellbore structure, formation elasticity, pipe elasticity, fluid compressibility, fluid rheology, etc. Real-time pressure oscillations during tripping/reaming are obtained. Based on geomechanical principles, in-situ stress around the wellbore is calculated by coupling transient wellbore pressure with surge and swab pressure, pore pressure, and original formation stress status to perform wellbore stability analysis.
By applying the breakout failure and wellbore fracture failure in the analysis, a workflow is proposed to obtain the safe operating window for tripping and reaming processes. Based on this study, it is determined that the safe drilling operation window for wellbore stability consists of more than just fluid density. The oscillation magnitude of transient wellbore pressure can be larger than the friction pressure loss during normal circulation process. With the effect of surge and swab pressure, the safe operating window can become narrower than expected. Although it is stable and not a concern during a normal penetration process, the wellbore stability can become problematic. By using the methodology described, unnecessary breakouts and borehole failures during tripping and reaming can be avoided. This work can also be used in the next generation of drilling automation.
This study provides insight into the integration of wellbore stability analysis and transient surge and swab pressure analysis, which is rarely discussed in the literature. It indicates that, when surge and swab pressure analysis is not carefully performed, the actual safe operating window can become narrower than originally predicted.
Designing Lost Circulation Material LCM Pills for High Temperature Applications
Authors: Kulkarni Sandeep D. , Savari Sharath , Gupta Nivika , Whitfill Don 
Published: August 2016

Abstract
Large-particle-size (d50 &gt; 300 μm) lost-circulation materials (LCMs) are often used to plug large fractures and manage downhole losses. They are usually added to a fluid to form a pill, which is pumped downhole. If downhole temperatures are high, these large particulates can settle out of the fluid, likely resulting in unsuccessful LCM treatments. This paper discusses temperature-stable fluids that suspend large LCMs and, thereby, efficiently address this challenge and mitigate lost circulation at high temperatures.
A detailed experimental study was conducted to study the rheology-vs.-temperature behavior of several fluids up to 325°F on advanced rheometers/viscometers. The suspension of large LCMs in these fluids at these temperatures was studied experimentally in a lab environment. The same LCM-fluid combinations were also investigated using the standard laboratory permeability plugging apparatus (PPA) tests at high temperatures. The slotted disc in a PPA simulates the fractures in the wellbore, and the slot plugging test is widely used in the industry to test the plugging efficiency of LCM particulates.
The temperature effect on the rheology of the fluids was demonstrated by plotting rheology-vs.-temperature data obtained from the rheometer/viscometers at various applied shear rates. The rheological investigation showed that fluids designed with certain combinations of viscosifiers provided stable rheologies (only a slight drop in rheology with temperature) at high temperatures. During the suspension tests, these temperature-stable fluids demonstrated a superior ability to suspend the large LCMs at high temperatures. The information agreed with the quantitative correlations in the literature on rheology requirements of the fluids to suspend given LCMs. The temperature-stable fluids also improved the LCM performance during the PPA tests, indicating their potential to mitigate losses effectively in high-temperature wells.
Post-Perforation Cleanup for Single Run Multizone Completion in a Complex Deepwater Well
Authors: Maher Peter 
Published: August 2016

Abstract
In deepwater and ultra-deepwater wells with multiple zones to complete, single-trip multizone completions are an increasingly common alternative to standard stacked completions. Several trips are saved by avoiding running plugs, stimulating, and then running sections of completion equipment. In addition to running the completion, stimulating, and gravel packing in a single run, today's multizone systems are rated for higher operating pressures, enabling higher pump rates and higher proppant volumes, as compared to conventional stacked completions. Along with the many benefits that single-trip multizone completions provide, they also introduce additional operational challenges in the well-completion process. One of these challenges is that multiple hydraulic set packers and screens must be run through perforation zones prior to being deployed at the intended depth. This necessitates a run to remove flash, burrs, and other debris that are left behind by the perforating operation from the casing and inside of the well. This is commonly referred to as a deburring run. In addition to restoring a smooth casing wall, a sump packer must be cleaned out and sufficient space below the packer cleared of debris for proper installation of the multizone completion. These two critical objectives have been addressed by running an innovative combination of wellbore clean-out tools, toolstring design, and detailed operating parameters.
Investigation of Shock Wave Interference in Low-Debris Perforating Gun System
Authors: Robey Eric , Hoelscher Chris 
Published: August 2016

Abstract
All perforating operations cause some debris. Perforating debris can damage surface equipment and completion tools and negatively impact production. In high-pressure deepwater wells, minimizing debris becomes more important because costs associated with debris accumulation might impact sensitive completion equipment or might not be realized until later in a well's life. This necessitates a new low-debris perforating system designed to significantly reduce debris associated with high-shot-density big-hole charges. Past solutions at low-shot densities have involved introducing materials into the perforator to retain debris. The close proximity of these materials to energetic components can introduce strong shock waves between individual charge detonation events. This phenomenon has an undesirable effect on perforator performance and should be minimized without compromising debris retention.
Traditional gun designs are based on a trial-and-error approach, using very limited post-testing measurements as design verification tools. The extremely complicated interactions among different components of the gun during a test cannot be observed experimentally, and the detailed physical process is not well understood. Therefore, numerical models have been developed to simulate the detailed dynamic responses of gun systems subjected to multiple shaped-charge detonations. This paper describes the coupling of hydrocode-based three-dimensional (3D) numerical models with FEA and full- scale surface testing. High-fidelity modeling is employed to capture the dynamic response of the materials under shock loading. The model is then used to investigate shock wave interference among the major components of the gun system. The underlying mechanics dominating the gun performance are identified. Consequently, considerable insight is obtained into gun system design for effective shock wave mitigation without compromising low-debris characteristics
Investigations are performed for the original baseline design and a modified design based on numerical simulation results. Numerical and experimental results are presented for both designs. By comparison, the modified design outperforms the baseline design, as predicted by the numerical model, thereby validating the numerical model and providing greater confidence to the design cycle.
Numerical simulations combined with the traditional experiments facilitate effective decision making, thus making the overall design cycle much more efficient.
Cementing Design and Placement Methods to Optimize Seal Integrity and Lower Cost for Deepwater Wells Drilled With Non-Aqueous Drilling Fluid
Authors: Sonnier Paul , Watters Larry , Clapper Dennis , Head Bill , Scherer George , Prod'homme Robert , Choi Myoungsung , Zhang Zhidong 
Published: August 2016

Abstract
The challenges of both primary and remedial cementing in Non-Aqueous Drilling Fluid (NAF) are well known in the deepwater industry. NAFs allow for stable drilling in high pressure high temperature (HPHT) and ultra-deepwater environments. However, mud properties that were beneficial for drilling become detrimental to completions. Fluid incompatibilities resulting from contamination, residue, fluid swapping and other fluid interactions can result in reduced compressive strength, channeling, downhole gelation and a poor cement bond. Incompatibility and incomplete hole cleaning can result in safety and environmental risks including job failure, future operational issues and loss of zonal isolation. Commercially available products are available to assist with mud displacement, however, there is a need for a fundamental characterization of mud-cement interactions on a chemical level to improve the knowledge of related technical risks and the technology required for risk reduction and long-term well integrity.
The objectives of this project are to develop fundamental knowledge of mud-cement compatibility issues related specifically to deepwater cementing, to quantify risks associated with cementing in NAF and to develop best practices and derive recommendations in order to reduce the recognized risks.
Investigating the Chemical Nature of Flat Rheology
Authors: Hilfiger Matthew G. , Thaemlitz Carl J , Moellendick Eric 
Published: August 2016

Abstract
The rheological properties of drilling fluids are crucial parameters in offshore operations, especially in the extreme conditions encountered during deepwater drilling. Oil based muds (OBM) are almost exclusively used in deepwater drilling operations, owing to such factors as their improved temperature stability, effectiveness when drilling through water sensitive formations, and capability to be utilized in narrow-margin drilling. A desired property of the drilling fluid is a minimal sensitivity of the flow properties with respect to temperature, leading to a flat-rheology system. Chemical additives provide the basis for the fluid's rheological properties, but are rarely addressed in detail within published literature. This paper reviews the chemistries of existing additives and their claimed uses. In addition to addressing the current state of the art, results are presented from an investigation into the effects of such emulsifier chemistries upon the rheological properties of the drilling fluid. This includes work on a novel emulsifier and comparative data to an industry standard incumbent. Through an improved study of the chemistry, a design-based approach can lead to the development of optimal properties for these high performance invert emulsion drilling fluids.
Solidification of Synthetic-Based Drilling Mud Using Geopolymers
Authors: Liu Xiangyu , Aughenbaugh Katherine , Nair Sriramya , Shuck Michelle , van Oort Eric 
Published: August 2016

Abstract
When constructing deepwater wells, incompatibility between synthetic-based mud (SBM) and Portland cements can lead to poor cementation and loss of cement integrity, which in turn may compromise zonal isolation. An alternative cementitious material based on geopolymers has been developed with improved SBM compatibility for primary and remedial cementing purposes as well as lost circulation control. Geopolymer benefits go beyond mere SBM compatibility: it is in fact possible to solidify non-aqueous fluids such as SBM and oil-based mud (OBM) using geopolymer formulations. This also means that non-aqueous fluids (SBM, OBM) can be disposed of in a cost-effective way, which presents a viable option for environmentally acceptable on-site or off-site disposal of drilling muds and cuttings.
Geopolymer is a type of alkali activated material that forms when an aluminosilicate precursor powder (such as fly ash) is mixed with an alkaline activating solution (such as sodium hydroxide). A novel SBM solidification method was developed by blending varied amounts of geopolymer and SBM. This solidification method was tested with various sources of precursor powders, SBMs and OBMs. The rheology and strength of the geopolymer/SBM blends were measured under downhole conditions.
Strength testing results showed that geopolymer cement lost only 30% of its strength when blended with 10% SBM, while a neat Portland slurry lost 70% strength. Geopolymer/SBM blends containing up to 40% SBM were found to have measurable strength when cured under downhole conditions. By changing the amount of geopolymer and SBM in the slurry, the geopolymer/SBM system can be developed into a lost circulation treatment with low compressive strength, or into a primary cementation material with higher compressive strength.
The geopolymer/SBM blends at different mixing ratios have shown great improvement in rheology of the geopolymer cement, allowing for pumpability of the slurry for well cementation. For instance, 30% SBM blends have downhole rheology profiles that approach those of neat Portland slurries.
Advanced Distributed Fiber Optic Sensors for Monitoring Poor Zonal Isolation with Hydrocarbon Migration in Cemented Annuli
Authors: Wu Qian , Nair Sriramya , Shuck Michelle , Oort Eric van , Guzik Artur , Kishida Kinzo 
Published: August 2016

Abstract
The cement annulus between a wellbore and a casing string should provide reliable zonal isolation throughout the life of a well. However, zonal isolation may be negatively affected by several factors which can compromise cement integrity and lead to the development of channels that provide migration paths for hydrocarbons. This paper is dedicated to monitoring the unwanted presence and migration of hydrocarbons in cemented annuli using a sophisticated fiber optic sensing system. The system is comprised of a distributed temperature and strain sensing (DTSS) data acquisition unit and a newly designed fiber optic cable that is capable of detecting hydrocarbons in cemented annuli. The DTSS system is based on Brillouin and Rayleigh backscattering mechanisms, which are sensitive to both strain and temperature changes. The cable consists of a single-mode optical fiber packaged with a hydrocarbon-sensitive polymer. This combination was tested extensively and successfully for its ability to identify cement integrity issues through detection of hydrocarbons in the cement. The presence of hydrocarbons causes the polymer around the fiber to swell, leading to changes in strain distribution on the fiber. These strain variations were detected using the DTSS monitoring system. The observed strain variations were found to be dependent on the type of fluids, which indicates that the proposed system has selective sensitivity to certain hydrocarbons. For example, synthetic-based mud had little effect on strain, while kerosene showed a significant response. In conclusion, the new fiber optic sensing system can be beneficial in verifying zonal isolation by detecting and monitoring any unwanted hydrocarbon migration in cemented annuli, identifying zones from which hydrocarbons are originating, and providing other essential information to identify the need for well intervention such as remedial cementing.
Effective Enhancement of Wellbore Stability in Shales with New Families of Nanoparticles
Authors: Gao C.. , Miska S. Z. , Yu M.. , Ozbayoglu E. M. , Takach N. E. 
Published: August 2016

Abstract
Traditional water based fluids tend to penetrate into shale formations, and interact with clay minerals, which results in clay swelling and wellbore instability. The larger content of clay in some deep water shales compared to regular onshore shales generates more wellbore instability problems. To reduce shale-fluid interaction, we need to reduce water invasion by sealing the pores and micro-fractures in shales. Therefore, the objectives of this study are to conduct pore pressure transmission (PPT) tests with test fluids that contain two new families of nanoparticles and to evaluate the major factors that affect pore pressure transmission.
For the first time, Mancos Shale and Eagle Ford Shale have been investigated with PPT tests using fluids that contain nanoparticles in different sizes (10 nm, 20 nm, 30 nm, 40 nm), types (aluminum oxide, magnesium oxide) and concentrations (3%, 10%). Results show that nanoparticles of 10 nm size can delay the time needed to reach the equilibrium state to 48.2 hours, compared to 27.8 hours needed for Eagle Ford Shale treated with suspensions that contain 40 nm nanoparticles. Based on the test matrix, the better combinations to decrease pore pressure at the equilibrium state are 10% 10 nm Al2O3 for Eagle Ford Shale and 10% 30 nm Al2O3 for Mancos Shale.
This relatively new plugging technique using nanoparticles has great practical potential for successful application in deep water drilling. A decrease in pore pressure transmission and the delay of the time to reach the equilibrium state will reduce problems of hydration and swelling in shale formations. This study can also help to define water based drilling fluid properties for the purpose of improving wellbore stability in deep water drilling.
Physical Measurement of Downhole Temperature Identifies Variance Between Mathematical Simulations
Authors: Mendonça G.. , Stair T.. , Fiorotti J. P. , Gabarra G.. , Cosentino A.. , Rogers H.. 
Published: August 2016

Abstract
Downhole temperature is a parameter of great importance when designing and testing cement slurries and other temperature dependent fluids. A set of recommendations has been published to determine downhole temperature. However, in the strictest sense, these recommendations are only applicable within a narrow set of well conditions. Recently, the industry practice has been to use mathematical simulation to estimate downhole temperature when well conditions fall outside the parameters given in this set of recommendations.
Accurate temperature estimates provide the best test parameters to be used during the qualification of mixtures under simulated downhole conditions. A lack of accurate data could result in premature or delayed cement setting. Both of these phenomena are unwelcome consequences that can result from failing to accurately estimate downhole temperature. It is therefore important to use a tool that best simulates downhole conditions. It is ideal if the results from mathematical simulation are validated using physical measurements. This paper documents how downhole temperature during fluid circulation was physically measured using temperature sensors and was then compared to mathematical simulations.
Multiple case histories are discussed, wherein both simulated and measured temperature were validated to provide improved accuracy of downhole temperature. This led to improved design, laboratory testing, and field implementation. Historical data are presented, demonstrating the importance of accurate temperature predictions. An overview is provided to include a historical review of methods used to estimate downhole temperature gradients and the benefits and potential drawbacks of available gradient tables. A review is presented comparing computational output with data obtained from measurement sensors, resulting in improved accuracy of predictive output. Improved gradient prediction methods are presented to help enable improved laboratory testing to be performed on temperature activated slurries.
The use of downhole temperature gages has been limited in deepwater applications. This paper introduces equipment designed specifically for deepwater applications, data collected, and comparative analysis with conventional mathematical models. The authors believe the material presented will be of interest to society membership.