When Slick is Not Smooth: Bottom-Hole Assembly Selection and Its Impact on Wellbore Quality

2021 ◽  
Author(s):  
Marc Willerth ◽  
Briana Dodson ◽  
Kelton McCue ◽  
Mahmoud Farrag
Keyword(s):  
Bend Angle ◽  
High Quality ◽  
Eagle Ford ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
Large Motor ◽  
Drilling Conditions ◽  
Bend Angles ◽  
The Impact ◽  
Selection Of

Abstract Appropriate selection of a bottom-hole assembly (BHA) is critical to the success of a drilling operation. In US Land drilling, these assemblies are often selected using local heuristics rather than rigorous analysis. These heuristics are frequently derived from the incentives of the directional contractor as opposed to incentives for the operator. Large motor bends enable more rotation though the curve and reduce the possibility of tripping for build rates. Unstabilized motors are believed to aid sliding and tool face control. Both of these practices lead to drilling a more tortuous wellbore and may cause problems later in the well’s life. This study quantifies the impact of these practices and proposes alternatives that can balance the needs of directional companies with the desire of operators for high-quality wellbores. Over 60 conventional motor assemblies used to drill curves in the Eagle Ford and Permian were analyzed for directional performance using commercial drillstring analysis software. The sliding and rotary tendencies were modelled through the curve across a range of potential drilling conditions. Expected build-rate models were validated by comparison to the maximum achieved doglegs in the directional surveys. When available, additional validation was performed using motor yields calculated from slide sheets. The validated models were compared to the dogleg severity requirements for each assembly’s respective well plan. Comparisons of slide ratios and slide/rotate tendencies of the BHAs were used to estimate the impact on wellbore quality using the tortuosity metric proposed by Jamieson (2019). Typical well plans for both basins had curves of 10 degrees/100ft with no well plan greater than 12 degrees/100ft. Typical bottom hole assemblies were capable of >15 degrees/100ft under normal sliding conditions, with some assemblies capable of >20 degrees/100ft of build. Predicted build rates were validated by slide sheets and observed dogleg severities. Common characteristics among assemblies with excess capacity were high bend angles (>=2 degrees) and minimal stabilization. These slick assemblies also had a strong drop tendency in rotation at low inclinations. The combination of high-build rate with rotary drop greatly increases tortuosity, particularly in the early stages of well. A minority of the assemblies used a lower motor bend angle (<2 degrees) combined with multiple stabilizers. These assemblies had a more consistent directional capability throughout the curve and held angle in rotation. The success of these assemblies confirms that a higher quality wellbore with an improved BHA design is technically achievable. As increasing attention is afforded to the topic of wellbore quality it is important to have methods available to technically achieve high-quality wellbores. In addition to the management of drilling practices, it is also important to have an appropriate BHA design that can enable those practices

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

CFD Evaluation of Bend Angle Effects on Sand Particle Erosion in Multiphase Flows

2020 ◽  
Author(s):  
A. Farokhipour ◽  
Z. Mansoori ◽  
M. Saffar-Avval ◽  
S. A. Shirazi ◽  
G. Ahmadi
Keyword(s):  
Erosion Rate ◽  
Industrial Applications ◽  
Bend Angle ◽  
Sand Particle ◽  
Liquid Particle ◽  
Particle Erosion ◽  
Particle Flows ◽  
Three Phase ◽  
Bend Angles ◽  
The Impact

Abstract In many industrial applications, gas-liquid-particle three-phase flows are observed. Predicting erosion damage in this type of flow is a challenging issue, and so many factors, such as the liquid film behavior have significant effects on the erosion rate. In the present study, the Eulerian-Lagrangian approach was implemented to study the process of sand particle erosion in elbows with different bend angles. For this purpose, gas and liquid phases under annular flow conditions were introduced at the pipe inlet, and the volume of fluid (VOF) method was employed to solve the governing equations. For evaluating the erosion rate, the Det Norske Veritas (DNV) model was applied. The predicted erosion results for the bend angles of 30°, 60° and 90° at different orientations were compared with those of the two-phase gas-particle flows. The simulation results indicated that for gas-liquid-particle flow, the behavior of film thickness in the bend plays a major role on the particle impact velocity and the corresponding erosion rates. By comparing the impact characteristics for gas and liquid superficial velocities of 40 and 0.4 m/s, respectively, in the 90° elbow, it was found that the impact velocities for gas-particle and gas-liquid-particle flows at the erosion hotspot are 38 and 14 m/s, respectively. In addition, among the studied geometries, the 30° elbow is the most erosion-resistant bend angle configuration among those studied for both two- and three-phase flows.

Calculation Methods of Orienter Torque and Drag in Coiled Tubing Drilling

2014 ◽  
Vol 1065-1069 ◽  
pp. 2049-2052
Author(s):  
Liang Hu ◽  
De Li Gao
Keyword(s):  
Static Friction ◽  
Maximum Output ◽  
Force Analysis ◽  
Viscous Forces ◽  
Coiled Tubing ◽  
Bottom Hole ◽  
Weight On Bit ◽  
Bottom Hole Assembly ◽  
The Impact ◽  
The Relationship

Hydraulic orienter has been widely used to alter the drilling direction downhole in coiled tubing drilling. A problem is encountered in construction field. When torque and drag of bottom hole assembly (BHA) are over the maximum output torque of orienter, This caused that it difficult to orient. Therefore, we need to calculate the maximum torque and drag in the process of orientation, it can provide a theoretical basis for designing and selecting the hydraulic orienter. Compared with the conventional force analysis, this paper additionally considered the case of zero weight on bit (WOB), the impact of the mud viscous forces and the relationship between dynamic and static friction, so that we can get more precise result of force analysis.

Proper Selection of Drill String Bottom-Hole Assembly for Directional Well Drilling

2014 ◽  
Vol 50 (9-10) ◽  
pp. 583-587
Author(s):  
S. A. Zaurbekov ◽  
B. Z. Kaliev ◽  
M. Zh. Muzaparov ◽  
Zh. N. Kadyrov ◽  
A. V. Kochetkov
Keyword(s):  
Drill String ◽  
Proper Selection ◽  
Well Drilling ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
Selection Of

Analysis of Oscillating Fishing Tool Efficiency for Stuck Assembly Recovery in Field X

2021 ◽  
Author(s):  
Pratama Wangsit Bayuartha ◽  
Parluhutan Alvin Sitorus ◽  
Rahmat Sinaga ◽  
Tomi Sugiarto ◽  
Kristoforus Widyas Tokoh ◽  
...  
Keyword(s):  
High Frequency ◽  
High Frequency Oscillation ◽  
Oil Reserves ◽  
Bottom Hole ◽  
Successful Case ◽  
Probability Of Success ◽  
Bottom Hole Assembly ◽  
Offshore Field ◽  
The Impact ◽  
Degree Of Recovery

Abstract As conventional fishing assembly offers a degree of recovery chance, such chance can be increased by utilizing an Oscillating Fishing Tool (OFT). The OFT is a fishing Bottom Hole Assembly (BHA) component that delivers low-magnitude; high-frequency oscillation. The continuous motion that the tool provides complements the impact generated by the fishing jar. This paper reviews the successful case history in Field X, which was in fact the first utilization of OFT for a fishing application in the field. Method of analysis involve comparing fishing sequence without and with the OFT. The OFT was used in Offshore Field X to recover a mechanically stuck 550-meter long Tubing Conveyed Perforating Gun assembly inside 9 5/8" casing that could potentially lead to loss of access into the 6 oil reserves candidate perforation zones. Initially the assembly had been stuck for two days, during which conventional fishing BHA was used to retrieve it to no avail, even after jarring for most of that time. OFT was then incorporated in the final fishing BHA and operated in combination with jarring operation. After around twelve hours of oscillating and jarring, the fish was able to be released from the initial stuck point. When tripping the string out, however, the assembly was stuck at high dog-leg severity area near the surface. At that point, in combination with applying substantial overpull, OFT was utilized further to recover the entire string. Upon fish retrieval, it was evident that post detonation, the TCP gun had swelled into 8.6 inches in diameter. In summary, oscillating and jarring for thirty-six cumulative hours successfully released the swelled TCP gun assembly from the stuck occurrences. In conclusion, the operation showed that the OFT serves as a higher level of fishing tool option that offers a particular excitation mode to the stuck assembly. Stuck assembly in a cased hole presents potential loss of oil reserves. Particularly in offshore application, the situation can also be costly. With reduced chance of recovery as time passes by, operation is hindered from being able to proceed to the next completion phase. The case proved OFT to have played an important role in improving fishing probability of success and should be considered as standard fishing BHA in the future.

scholarly journals Slower development of lower canopy beans produces better coffee

2020 ◽  
Vol 71 (14) ◽  
pp. 4201-4214 ◽  
Author(s):  
Bing Cheng ◽  
Heather E Smyth ◽  
Agnelo Furtado ◽  
Robert J Henry
Keyword(s):  
Gene Expression ◽  
Metabolic Pathways ◽  
Global Gene Expression ◽  
Coffee Production ◽  
High Quality ◽  
Development Stages ◽  
Expression Of Genes ◽  
Coffee Beans ◽  
The Impact ◽  
Selection Of

Abstract The production of high-quality coffee is being challenged by changing climates in coffee-growing regions. The coffee beans from the upper and lower canopy at different development stages of the same plants were analyzed to investigate the impact of the microenvironment on gene expression and coffee quality. Compared with coffee beans from the upper canopy, lower canopy beans displayed more intense aroma with higher caffeine, trigonelline, and sucrose contents, associated with greater gene expression in the representative metabolic pathways. Global gene expression indicated a longer ripening in the lower canopy, resulting from higher expression of genes relating to growth inhibition and suppression of chlorophyll degradation during early bean ripening. Selection of genotypes or environments that enhance expression of the genes slowing bean development may produce higher quality coffee beans, allowing coffee production in a broader range of available future environments.

scholarly journals Methods and technical solutions for keeping the path of a geotechnological borehole

2021 ◽  
Vol 6 (1) ◽  
pp. 42-51
Author(s):  
D. N. Moldashi
Keyword(s):  
Economic Effect ◽  
Drill String ◽  
Soft Rocks ◽  
Bottom Hole ◽  
Ore Bodies ◽  
Drilling Tools ◽  
Wide Range ◽  
Bottom Hole Assembly ◽  
Drilling Conditions ◽  
Technical Solutions

With increasing depth of exploration and process boreholes (at small drilling diameters), the probability of deviation of the borehole path from design trajectory increases many times; i. e. zenith curvature and azimuth deviation of the borehole path occur. Therefore, developing methods for keeping vertical path of the borehole when drilling deeper horizons of ore bodies is a very topical issue. The paper presents the results of developing a new bottom-hole assembly for drilling boreholes in soft rocks using screw casing centralizers, which provide good stabilizing and centering effects to mitigate horizontal departure of the hole axis from the design direction and minimize vertical curvature of the hole path (zenith angle) while maintaining sufficient drill string flexibility. The developed technical solutions provide simplicity of design and ability to adapt to wide range of mining, geological and technological drilling conditions. The feasibility of manufacturing the centralizers by own efforts and the technological feasibility of quick and easy connecting the centralizer with other elements of the bottom-hole assembly have been substantiated. The manufacture efficiency is proved by the use of inexpensive and wear-resistant materials in the centralizer armouring, for which tungsten-cobalt or titanium-cobalt hard-alloy inserts were used. In addition, prevailing volume of borehole drilling in soft rocks allowed using replaceable centering elements, as well as their repair and restoration to increase their service life. The manufactured centralizer has a low production cost due to the design simplicity and the use of inexpensive wearresistant material and will compete in the market of drilling tools and technical devices for drill string stabilization. The economic effect from the introduction of the self-produced centralizers amounted to more than 170,000 tenge per a borehole.

Post Well Vibration Analysis in the North Sea: A Tool to Understand Drilling Performance

2015 ◽  
Author(s):  
M. F. Al Dushaishi ◽  
R. Nygaard ◽  
E. Hoel ◽  
S. Hellvik ◽  
M. Andersen
Keyword(s):  
North Sea ◽  
Vibration Damping ◽  
Rate Of Penetration ◽  
Drill Stem ◽  
The North ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The North Sea ◽  
The Impact

Severe drill stem vibrations could leads to excessive damage to the bottom hole assembly causing an increase in nonproductive time. Different drill stem vibrations models are used to predict and avoid resonance regions by optimizing the selection of bottom hole assembly components and operating parameters such as weight on bit, and surface RPM. In addition to avoid the resonance regions, specialized tools have been developed to reduce vibrations. However a complete understanding on how to mitigate vibration and its effect on drilling performance is still lacking. This study investigates the cause of drill stem vibrations, its effect on drilling performance, and the effect of including vibration reductions tools in the bottom hole assembly design in several recent drilled wells in the North Sea. Vibration damping tools used in this study were able to reduce both lateral and torsional drill stem vibration compared to a well with no vibration damping tool. Torsional drill stem vibrations tend to increase through rich sand zones causing an increase in lateral vibrations. The impact drill stem vibrations have on drilling performance was identified through rate of penetration. As lateral vibration intensity increases, instantaneous rate of penetration decreases.

scholarly journals Numerical Modeling of Dynamic Behavior and Steering Ability of a Bottom Hole Assembly with a Bent-Housing Positive Displacement Motor Under Rotary Drilling Conditions

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2568 ◽  
Author(s):  
Yingjie Chen ◽  
Jianhong Fu ◽  
Tianshou Ma ◽  
Anping Tong ◽  
Zhaoxue Guo ◽  
...  
Keyword(s):  
Dynamic Stress ◽  
Impact Force ◽  
Axial Loading ◽  
Drill Bit ◽  
Deviation Angle ◽  
Rotary Drilling ◽  
Positive Displacement ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

Fully rotary drilling is one of many useful technologies used for the exploitation of petroleum and geothermal resources, but fully rotating drill-strings are extremely complicated. Therefore, according to the Hamilton principle, a non-linear coupled bottom hole assembly (BHA)-bit-formation-wellbore model is proposed for BHAs with bent-housing positive displacement motor using the finite element method to investigate the dynamic behavior and steering ability under fully rotary drilling. The impact force, acceleration, axial loading, torque, and dynamic stress were simulated, and factors influencing the dynamic steering forces were investigated. The results indicate that the impact force, acceleration, axial loading, torque, and dynamic stress under fully rotary drilling are much higher than under conventional drilling. The numerical simulation and field test in well B confirmed that the rotation of the drill-string is conducive to the hold-on of the deviation angle. With the increase in the weight-on-bit, bend angle, and stabilizer height, the deflecting force on a drill bit increases. Conversely, with the increase in stabilizer diameter, the deflecting force on the drill bit decreases; the lower the deflecting force, the better the effectiveness of hold-on. With increasing deviation angle, the deflecting force on the drill bit first decreases and then increases. The present model can provide a theoretical basis for wellbore trajectory control and optimization design of BHA.

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