scholarly journals Evaluation of Deep Geothermal Exploration Drillings in the Crystalline Basement of the Fennoscandian Shield Border Zone in South Sweden.

2021 ◽  
Author(s):  
Jan-Erik Rosberg ◽  
Mikael Erlström
Keyword(s):  
Thermal Properties ◽  
Feasibility Studies ◽  
Crystalline Basement ◽  
Fennoscandian Shield ◽  
Border Zone ◽  
Rotary Drilling ◽  
Drilling Performance ◽  
Geological Conditions ◽  
Air Drilling ◽  
South Sweden

Abstract The 3.1 and 3.7 km deep FFC-1 and DGE-1 geothermal explorations wells drilled into the Precambrian crystalline basement on the southern margin of the Fennoscandian Shield are evaluated regarding experiences from drilling, geological conditions, and thermal properties. Both wells penetrate an approximately two-kilometre-thick succession of sedimentary strata before entering the crystalline basement, of granitoid gneiss, metabasite and amphibolite of the (1.1–0.9 Ga) Eastern Interior Sveconorwegian Province. The upper c. 400 m of the basement is in FFC-1 severely fractured and water-bearing which disqualified the use of percussion air drilling and conventional rotary drilling was therefore performed for the rest of the borehole. The evaluation of the rotary drillings in FFC-1 and DGE-1 gave that the average bit life was very similar, 62 m respectively 68 m as well as an average ROP between 2 and 4 m/h without any preferences regarding bit-type (PDC or TCI) or geology. A bottomhole temperature of 84.1 °C in FFC-1 borehole with gradients varying between 17.4 °C/km and 23.5 °C/km for the main part of the borehole. The calculated heat flow varies between 51 and 66 mW/m2 and the average heat production is 3.0 µW/m3. The basement is in FFC-1 overall depleted of uranium and thorium in comparison to DGE-1 where the heat productivity is overall higher with an average of 5.8 µW/m3. The spatial distribution of fractures was successfully mapped using borehole imaging logs in FFC-1 and shows a dominance of N–S oriented open fractures, a fracture frequency varying between 0.85 and 2.49 frac/m and a fracture volumetric density between 1.68 and 3.39 m2/m3. The evaluation of the two boreholes provides insight and new empirical data on the thermal properties and fracturing of the concealed crystalline basement in the Fennoscandian Shield Border Zone that previously only been assessed by assumptions and modelling. The outcome of the drilling operation has also provided insight regarding the drilling performance of the basement and statistical data on various drill bits used. Properties and experiences which are all important in feasibility studies of deep geothermal project in the crystalline basement in south Sweden.

scholarly journals Evaluation of deep geothermal exploration drillings in the crystalline basement of the Fennoscandian Shield Border Zone in south Sweden

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jan-Erik Rosberg ◽  
Mikael Erlström
Keyword(s):  
Thermal Properties ◽  
Feasibility Studies ◽  
Crystalline Basement ◽  
Fennoscandian Shield ◽  
Border Zone ◽  
Rotary Drilling ◽  
Drilling Performance ◽  
Geological Conditions ◽  
Air Drilling ◽  
South Sweden

AbstractThe 3.1- and 3.7-km-deep FFC-1 and DGE-1 geothermal explorations wells drilled into the Precambrian crystalline basement on the southern margin of the Fennoscandian Shield are evaluated regarding experiences from drilling, geological conditions, and thermal properties. Both wells penetrate an approximately 2-km-thick succession of sedimentary strata before entering the crystalline basement, dominated by orthogneiss, metabasite and amphibolite of the (1.1–0.9 Ga) Eastern Interior Sveconorwegian Province. The upper c. 400 m of the basement is in FFC-1 severely fractured and water-bearing which disqualified the use of percussion air drilling and conventional rotary drilling was, therefore, performed for the rest of the borehole. The evaluation of the rotary drillings in FFC-1 and DGE-1 showed that the average bit life was very similar, 62 m and 68 m, respectively. Similarly, the average ROP varied between 2 and 4 m/h without any preferences regarding bit-type (PDC or TCI) or geology. A bottomhole temperature of 84.1 °C was measured in FFC-1 borehole with gradients varying between 17.4 and 23.5 °C/km for the main part of the borehole. The calculated heat flow varies between 51 and 66 mW/m2 and the average heat production is 3.0 µW/m3. The basement in FFC-1 is, overall, depleted in uranium and thorium in comparison to DGE-1 where the heat productivity is overall higher with an average of 5.8 µW/m3. The spatial distribution of fractures was successfully mapped using borehole imaging logs in FFC-1 and shows a dominance of N–S oriented open fractures, a fracture frequency varying between 0.85 and 2.49 frac/m and a fracture volumetric density between 1.68 and 3.39 m2/m3. The evaluation of the two boreholes provides insight and new empirical data on the thermal properties and fracturing of the concealed crystalline basement in the Fennoscandian Shield Border Zone that, previously, had only been assessed by assumptions and modelling. The outcome of the drilling operation has also provided insight regarding the drilling performance in the basement and statistical data on various drill bits used. The knowledge gained is important in feasibility studies of deep geothermal projects in the crystalline basement in south Sweden.

Evaluation of Belleville Springs and Damping Through Static Cyclic Loading “Hysteresis” for pVARD Optimization: Part-I

2021 ◽  
Author(s):  
Abdelsalam Abugharara ◽  
Stephen Butt
Keyword(s):  
Data Analysis ◽  
Cyclic Loading ◽  
Dynamic Compression ◽  
Range Data ◽  
Compression Tests ◽  
Rotary Drilling ◽  
Static Compression ◽  
Drilling Performance ◽  
Wide Range ◽  
Compression Hysteresis

Abstract One unconventional application that researchers have been investigating for enhancing drilling performance, has been implemented through improving and stabilizing the most effective downhole drilling parameters including (i) increasing downhole dynamic weight on bit (DDWOB), (ii) stabilizing revolution per minutes (rpm), (iii) minimizing destructive downhole vibrations, among many others. As one portion of a three-part-research that consists of a comprehensive data analysis and evaluation of a static compression hysteresis, dynamic compression hysteresis, and corresponding drilling tests, this research investigates through static cyclic loading “Hysteresis” of individual and combined springs and damping the functionality of the passive Vibration Assisted Rotary Drilling (pVARD) tool that could be utilized towards enhancing the drilling performance. Tests are conducted on the two main pVARD tool sections that include (i) Belleville springs, which represent the elasticity portion and (ii) the damping section, which represents the viscous portion. Firstly, tests were conducted through static cyclic loading “Hysteresis” of (i) a mono elastic, (ii) a mono viscus, and (iii) dual elastic-viscus cyclic loading scenarios for the purpose of further examining pVARD functionality. For performing static compression tests, a calibrated geomechanics loading frame was utilized, and various spring stacking of different durometer damping were tested to seek a wide-range data and to provide a multi-angle analysis. Results involved analyzing loading and displacement relationships of individual and combined springs and damping are presented with detailed report of data analysis, discussion, and conclusions.

Casing While Drilling Application: Changing Mitigation to a Performance

2021 ◽  
Author(s):  
Alexey Ruzhnikov ◽  
Fahad AlHosni ◽  
Edgar Garnica Echevarria ◽  
Rodrigo Varela
Keyword(s):  
Extensive Study ◽  
Drilling Process ◽  
Wellbore Instability ◽  
Existing Problems ◽  
Drilling Performance ◽  
Geological Conditions ◽  
Pdc Bit ◽  
Low Torque ◽  
The Cost ◽  
A Performance

Abstract Well construction process through the unstable formations prone to total losses, pack-off and water influx is challenging. The manuscript describes the casing while drilling (CwD) combined with stage-cementing tool as introduced solution, when the challenge was to ensure that torque limit is not reached while drilling and estimate the effect of CwD on curing total losses and bring the casing while drilling performance to the level of conventional drilling. Introduction of CwD required extensive study of the potential torque while drilling as existing stage-cementing tools have low torque rating. Additionally, the casing fatigue may be a factor affecting the operations what lead to an introduction of magnetic particle casing inspection. The CwD bit design was adopted to the geological conditions based on best performance of the PDC bit, and originally selected drilling parameters were further optimized based on the result of the first runs. As the drilling of the well required utilization of mud cap for well control purposes, the mud recipes were adjusted to optimize the drilling performance and minimize the cost implication. The proposed solutions allowed to eliminate the problem with wellbore instability and related stuck pipe events. Further the proper engineering of the drilling process allowed significantly increase the rate of penetration since the beginning of the implementation, when the drilling torque never reached the limit even at 7,000 ft depth. The manuscript describes in detail the approach to make a proper design of CwD process focusing on prevention of existing problems and aiming to convert mitigation tool to a performance tool. Additionally, in details described the studied effect of CwD on curing total losses in highly fractured environment.

Drilling Cutting Analysis to Assist Drilling Performance Evaluation in Hard Rock Hole Widening Operation

2020 ◽  
Author(s):  
Daiyan Ahmed ◽  
Yingjian Xiao ◽  
Jeronimo de Moura ◽  
Stephen D. Butt
Keyword(s):  
Performance Enhancement ◽  
Ore Deposits ◽  
Drilling Process ◽  
Rotary Drilling ◽  
Pilot Hole ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Weight On Bit ◽  
Drilling Operations

Abstract Optimum production from vein-type deposits requires the Narrow Vein Mining (NVM) process where excavation is accomplished by drilling larger diameter holes. To drill into the veins to successfully extract the ore deposits, a conventional rotary drilling rig is mounted on the ground. These operations are generally conducted by drilling a pilot hole in a narrow vein followed by a hole widening operation. Initially, a pilot hole is drilled for exploration purposes, to guide the larger diameter hole and to control the trajectory, and the next step in the excavation is progressed by hole widening operation. Drilling cutting properties, such as particle size distribution, volume, and shape may expose a significant drilling problem or may provide justification for performance enhancement decisions. In this study, a laboratory hole widening drilling process performance was evaluated by drilling cutting analysis. Drill-off Tests (DOT) were conducted in the Drilling Technology Laboratory (DTL) by dint of a Small Drilling Simulator (SDS) to generate the drilling parameters and to collect the cuttings. Different drilling operations were assessed based on Rate of Penetration (ROP), Weight on Bit (WOB), Rotation per Minute (RPM), Mechanical Specific Energy (MSE) and Drilling Efficiency (DE). A conducive schedule for achieving the objectives was developed, in addition to cuttings for further interpretation. A comprehensive study for the hole widening operation was conducted by involving intensive drilling cutting analysis, drilling parameters, and drilling performance leading to recommendations for full-scale drilling operations.

Torsional Vibration Analysis of Drillstrings in Blasthole Drilling

2008 ◽  
Author(s):  
Omid Aminfar ◽  
Amir Khajepour
Keyword(s):  
Torsional Vibration ◽  
Natural Frequencies ◽  
Element Model ◽  
Drilling Process ◽  
Torsional Vibrations ◽  
Rotary Drilling ◽  
Well Drilling ◽  
State Response ◽  
Drilling Performance ◽  
Overall Performance

Reducing vibrations in well drilling has a significant effect on improving the overall performance of the drilling process. Vibrations may affect the drilling process in different ways, i.e., reducing durability of the drillstring’s elements, reducing the rate of penetration, and deviating the drilling direction. In rotary drilling, which is used to open mine and oil wells, torsional vibration of the drillstring is an important component of the overall system’s vibration that has received less attention in the literature. In this paper, we propose a finite element model for a sample blasthole drillstring used to open mine wells to investigate its torsional vibrations. Boundary conditions and elements’ specifications are applied to this model. In the model, the interaction between the insert and the rock is represented by a set of repetitive impulses according to the insert pattern. The steady-state response of the system to the repetitive impulses is found and natural frequencies, kinetic energy, and potential energy of the drillstring are calculated. The root mean square (RMS) of the total energy can be used as the measure for reducing the torsional vibration of the system. Finally, an optimum combination of inserts on the cone’s rows was found based on minimizing the total vibratory energy of the drillstring. The optimum design can reduce the torsional vibrations of the drillstring and improve the drilling performance.

scholarly journals High-resolution magnetotelluric studies of the Archaean-Proterozoic border zone in the Fennoscandian Shield, Finland

2012 ◽  
Vol 188 (3) ◽  
pp. 908-924 ◽  
Author(s):  
K. Vaittinen ◽  
T. Korja ◽  
P. Kaikkonen ◽  
I. Lahti ◽  
M. Yu. Smirnov
Keyword(s):  
High Resolution ◽  
Fennoscandian Shield ◽  
Border Zone

Modeling and Predicting Performance of Autonomous Rotary Drilling System Using Machine Learning Techniques

2021 ◽  
Author(s):  
Kingsley Amadi ◽  
Ibiye Iyalla ◽  
Radhakrishna Prabhu
Keyword(s):  
Machine Learning ◽  
Energy Conservation ◽  
Real Time ◽  
Model Performance ◽  
Machine Learning Techniques ◽  
Optimization Models ◽  
Optimum Operating ◽  
Functional Feature ◽  
Rotary Drilling ◽  
Drilling Performance

Abstract This paper presents the development of predictive optimization models for autonomous rotary drilling systems where emphasis is placed on the shift from human (manual) operation as the driving force for drill rate performance to Quantitative Real-time Prediction (QRP) using machine learning. The methodology employed in this work uses real-time offset drilling data with machine learning models to accurately predict Rate of Penetration (ROP) and determine optimum operating parameters for improved drilling performance. Two optimization models (physics-based and energy conservation) were tested using Artificial Neutral Network (ANN) algorithm. Results of analysis using the model performance assessment criteria; correlation coefficient (R2) and Root Mean Square Error (RMSE), show that drill rate is non-linear in nature and the machine learning model (ANN) using energy conservation is most accurate for predicting ROP due to its ability in establishing a functional feature vector based on learning from past events.

scholarly journals Study on Environment-friendly Cooling Air Drilling Performance without Oil.

2000 ◽  
Vol 66 (5) ◽  
pp. 719-724
Author(s):  
Seiji OKUMURA ◽  
Kazuhiko YOKOGAWA ◽  
Shigeo SHIMIZU ◽  
Munehiko YOKOGAWA
Keyword(s):  
Environment Friendly ◽  
Drilling Performance ◽  
Air Drilling ◽  
Cooling Air

Efficient PDC Bit Designs Reduced Vibrational Impact While Drilling with Rotary Steerable Systems in the Geological Conditions of the Yamalo-Nenets Autonomous District

2021 ◽  
Author(s):  
Andrey Vyacheslavovich Garipov ◽  
Andrey Aleksandrovich Rebrikov ◽  
Aydar Ramilevich Galimkhanov ◽  
Andrey Valerievich Mikhaylov ◽  
Almaz Sadrikhanovich Khalilov ◽  
...  
Keyword(s):  
Drill Pipe ◽  
Polycrystalline Diamond ◽  
Rock Properties ◽  
Construction Time ◽  
Test Beam ◽  
Specialized Software ◽  
Drilling Performance ◽  
Geological Conditions ◽  
Vibration Impact ◽  
Nenets Autonomous

Abstract This article is a description of a comprehensive engineering approach to new designs of PDC (Polycrystalline Diamond Compact) Bits and bottomhole equipment for efficient horizontal wells drilling in the Yamal-Nenets Autonomous Okrug (YNAO) fields with Rotary Steerable Systems (RSS) Point the Bit (PTB) type. The paper represents an analysis of the efficiency of drilling rocks of various hardness depending on the bits, the bottom hole assembly (BHA), and type of vibrations. In the Yamal region fields a main constraint of sub horizontal sections drilling performance for liner run in hole is the occurrence of vibrations. The predominant vibration types are Stick and Slip (S&S) and High Frequency Torsional Oscillations (HFTO). These types of vibrations often had to be reduced by limiting drilling regime (weight on bit (WOB), drill pipe (DP) RPM, and flow rate), which directly affected on the rate of penetration (ROP). To find solutions to this problem for drilling performance improvement, geological and geomechanically modeling of rock properties and an analysis of burst-files of vibrations (modeled in specialized software) were carried out based on downhole data. The studies have found key factors that cause the high vibration impact and reasons for premature wear of the PDC bits, which served as a basis for identifying the shortcomings of previous bit designs. Test beam experiments were also performed to assess the bits wear while drill-out of the casing accessories. The results formed the basis for development of new PDC bits designs using specialized software. As an output new 155.6/152.4 mm bits designs with an innovative cutting structure that considers the geological features and technical aspects of drilling liner sections in YNAO fields were manufactured. The new bit designs have significantly reduced vibration levels, improved ROP performance in the liner section using RSS PTB, and decreased the overall well construction time. These solutions open wide opportunities for their further implementation on other projects both in Russia and in other CIS countries.

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