Extreme Drilling Research Articles

Acetylation of Cellulose Nanocrystals Extracted from Cotton for Drilling Fluid Application: Structural and Thermal Characterization

In petroleum exploration, cellulose derivatives such as carboxymethylcellulose (CMC) are frequently used in drilling, cementing and fracturing fluids. However, under extreme drilling conditions, these additives have limited performance. In this regard, cellulose nanocrystals particles (CNCs) which are also derived from cellulose material are a suitable candidate due to their shear thinning rheology and thixotropy properties, even at low concentrations, among so many properties thanks to their crystalline structure and their nanometric dimensions.In this work, hydrolyzed fibers from industrial cotton are acetylated using acetic anhydride and sulfuric acid as catalysts, with the aim to modify surface properties of the obtained CNCs without changing their fiber structure and morphology. FTIR analysis pointed out the acetylation success of the obtained nanocrystals whose dimensions were found to be unaltered by the modification process. SEM images of cotton nanocrystal indicate that CNCcsurface modification preserves the nanoscale dimensions of the nanoparticles. Also, TGA analysis showed thermal stability for the acetylated CNCc.

Drilling of deep and ultra-deep wells for prospecting and exploration of new raw mineral fields

Scientific and technological progress over the last century has led to an enormous increase in the consumption of minerals, including energy resources. Most of the exploited oil and gas fields are already considerably depleted, so it is necessary to search for new hydrocarbon resources, particularly at great depths. Deep drilling plays a special role in solving this problem. The article considers the world and Russian experience of ultra-deep wells drilling. The me-thods and technologies used in the construction of wells, as well as complications and accidents occurring during their drilling were analyzed. The analysis revealed that the existing limitations for drilling parameters of deep and ultra-deep wells are caused by the technical characteristics of surface and bottomhole drilling equipment, which do not meet the extreme drilling conditions. The directions for development of deep and ultra-deep well drilling machinery and technologies are suggested. The notion of extreme rock and geological drilling conditions is introduced, which describes drilling in conditions of hydrostatic pressure of flushing fluid column and high bottomhole temperature both at stable and unstable wellbore conditions, coming close to the upper limit of operating technical characteristics of bottomhole assembly, the drill string and flushing fluid.

CFD Validation for Assessing the Repercussions of Filter Cake Breakers; EDTA and SiO2 on Filter Cake Return Permeability

ABSTRACT Drill-in-fluids create what are known as filter cakes. Filter cakes, in some cases, lead to well abandonment because they prevent hydrocarbons from flowing freely from the formation into the wellbore. Cake removal is essential to avoid formation damage. A previous study on filter cake breakers was considered for computational fluid dynamic (CFD) validation. Matlab-CFD and Navier-Stokes equations aimed at predicting and validating visual, multiphase flow under finite element analysis (FEA). The interactions of separate chemical breakers and drill-in-fluid such as ethylenediaminetetraacetic acid (EDTA), silica-nanoparticle (SiO2), and biodegradable synthetic-based mud drill-in-fluid (BSBMDIF) were monitored under a particle size distribution, viscosity, density, and pressure. Predicting return permeability of filter cake was considered under a simple filtration process. The particles’ deposition created pore spaces between them; barite 74 μm, nano-silica 150 nm, and EDTA 10 μm generally closed up the pores of the filtration medium. Under extreme drilling conditions, barite formed thicker regions, and EDTA chemical properties easily disjointed these particles, while SiO2 entirely did not. The experimented results of (EDTA) and SiO2 for return permeability were in full force agreeable with the 2D simulation. A hybrid computational analysis considering CFD under discrete element analysis and neural network can be employed for further research validations.

Well Control Simulation With Nonaqueous Drilling Fluids

Abstract The demand for energy has increased recently worldwide, requiring new oilfield discoveries to supply this need. Following this demand increase, challenges grow in all areas of the petroleum industry especially those related to drilling operations. Due to hard operational conditions found when drilling complex scenarios such as high-pressure/high-temperature (HPHT) zones, deep and ultradeep water, and other challenges, the use nonaqueous drilling fluids became a must. The reason for that is because this kind of drilling fluid is capable to tolerate these extreme drilling conditions found in those scenarios. However, it can experience changes in its properties as a result of pressure and temperature variations, requiring special attention during some drilling operations, such as the well control. The well control is a critical issue since it involves safety, social, economic, and environmental aspects. Well control simulators are a valuable tool to support well control operations and preserve the well integrity, verifying operational parameters and to assist drilling engineers in the decision-making process during well control operations and kick situations. They are also important computational tools for rig personnel training. This study presents well control research and development contributions, as well as the results of a computational well control simulator that applies the Driller's method and allows the understanding the thermodynamic behavior of synthetic drilling fluids, such as n-paraffin and ester base fluids. The simulator employed mathematical correlations for the drilling fluids pressure–volume–temperature (PVT) properties obtained from the experimental data. The simulator results were compared to a test well data set as well to the published results from other kick simulators.

Advanced Technologies and Solutions for Challenging Drilling Applications

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 170566, ’Advanced Technologies and Practical Solutions for Challenging Drilling Applications,’ by M.J. Jellison, SPE, NOV Grant Prideco, and A. Chan, Workstrings International, prepared for the 2014 SPE Asia Pacific Drilling Technology Conference and Exhibition, Bangkok, Thailand, 25-27 August. The paper has not been peer reviewed. This paper provides a review of recent technology advancements and addresses practical considerations associated with drillpipe and drillstem components for extreme drilling applications. Recent developments and enhancements in these connection designs, including new higher-strength materials, advanced thread forms, and associated improvements in torsional strength and fatigue performance, are presented. The paper discusses the engineering solutions implemented to overcome the high forces, slip-crushing concerns, and material-strength and toughness considerations for these critical applications. Third-Generation Double-Shoulder Connection Since the introduction of the second-generation double-shoulder connection (DSC), the industry trend has continued toward deeper and longer-reach wells, which has dictated the need for drillpipe connections with enhanced mechanical and dimensional characteristics coupled with improved makeup/ breakout speeds. Consequently, a project was commissioned to design, analyze, laboratory test, and field trial the industry’s first third-generation DSC. A key objective of the project was to improve connection makeup/breakout speeds significantly. Mechanical and hydraulic gains were also dictated on the basis of the industry’s trend toward deeper and longer-reach wells.

NETL Extreme Drilling Laboratory Studies High Pressure High Temperature Drilling Phenomena

The U.S. Department of Energy’s National Energy Technology Laboratory (NETL) established the Extreme Drilling Laboratory to engineer effective and efficient drilling technologies viable at depths greater than 20,000 ft. This paper details the challenges of ultradeep drilling, documents reports of decreased drilling rates as a result of increasing fluid pressure and temperature, and describes NETL’s research and development activities. NETL is invested in laboratory-scale physical simulation. Its physical simulator will have capability of circulating drilling fluids at 30,000 psi and 480°F around a single drill cutter. This simulator is not yet operational; therefore, the results will be limited to the identification of leading hypotheses of drilling phenomena and NETL’s test plans to validate or refute such theories. Of particular interest to the Extreme Drilling Laboratory’s studies are the combinatorial effects of drilling fluid pressure, drilling fluid properties, rock properties, pore pressure, and drilling parameters, such as cutter rotational speed, weight on bit, and hydraulics associated with drilling fluid introduction to the rock-cutter interface. A detailed discussion of how each variable is controlled in a laboratory setting will be part of the conference paper and presentation.

Overview: Drilling Technology (February 2008)

Overview An increasing number of superlatives are used to describe challenges that the drilling industry faces. Indeed, adjectives such as high, extreme, long, ultra, severe, or extra are used quite often to qualify the complexity of wells drilled today or that will be drilled in the near future. To name a few, one hears about ultradeep offshore, ultradeep drilling, ultraslim tools, very-extended-reach drilling, high-rate data transmission, ultrahigh torque connections, ultrahigh-strength steel, high-accuracy measurement, very advanced modeling, high-definition visualization, high-performance, and many others. Drilling becomes less and less conventional in terms of materials, techniques, data acquisition, and transmission systems and turns into unconventional or extreme drilling by use of new technologies and operating limits. Another observation is that the drilling industry attempts to combine and integrate several drilling techniques and methods, not only to overcome the difficulty and complexity of drilling deeper, longer, and in higher pressure and temperature in a severe downhole environment, but also to extend the production of mature or depleted fields. For example, it is not rare to combine coiled-tubing drilling with underbalanced-drilling methods, or an ultraslim rotary-steerable system with a casing-while-drilling (CWD) system. There is talk about combining CWD technology with expandable tubulars. In brief, complex-drilling challenges will find their economic and engineering solutions by mixing several high-level technologies. Papers presented on the following pages and in the additional reading illustrate these technology trends.Ultradeep or extra-long drilling requires increasingly higher-strength drillpipe and advancements in material to reach the target successfully and safely.Drilling technology must be accompanied with realistic and advanced modeling or laboratory experiments to obtain better benefit from and understanding of complex hydraulic and mechanical phenomena.New managed-pressure-drilling methods are required to compensate dynamic pressure in reservoirs having a low margin between the fracture- and the pore-pressure gradients. Drilling Technology additional reading available at the SPE eLibrary: www.spe.org SPE 110708 "Case Study: Drillstring-Failure Analysis and New Deep-Well Guidelines Lead to Success" by David R. Bert, SPE, BP plc, et al. SPE 107903 "Implementation of a Shock- and Vibration-Mitigation Process: Achieving Real-Time Solutions and Savings" by Goke Akinniranye, SPE, Schlumberger, et al. SPE 107547 "Improved Drilling-Process Control Through Continuous Particle and Cuttings Monitoring" by T.H. Omland, Statoil, et al. SPE 109530 "The Extraction of Mud-Stuck Tubulars Using Vibratory Resonant Techniques" by Ozzie Gonzalez, Vibration Technology, et al.