Analytical Model to Estimate the Drag Forces for Microhole Coiled Tubing Drilling

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yuan Zhang ◽  
Ye Hao ◽  
Robello Samuel
Keyword(s):  
Analytical Model ◽  
New Technology ◽  
Drilling Process ◽  
Fluid Viscosity ◽  
Coiled Tubing ◽  
Drag Forces ◽  
Drag Models ◽  
Improved Model ◽  
Horizontal Portion ◽  
Surface Loads

Microhole coiled tubing drilling is a new technology that provides many added advantages but at the same time poses numerous operational challenges. This manifests itself in a number of ways, all of which adversely affect the efficiency of the drilling process. These problems include increased wellbore friction, poor hole-cleaning, tubular failures, and associated problems during tripping operations. Presently conventional torque and drag models are used to calculate drag forces and surface loads during microhole coiled tubing drilling. However, these estimates might be under conservative. Therefore, an improved model and more comprehensive analysis are required. Conditions expected during microhole coiled tubing drilling are completely different from those encountered during conventional drilling. Further complexity is added when the wellbore is undulated. This paper describes a new analytical model for estimating drag forces by assuming that pipe in the horizontal portion follows a sine function wave due to residual bends and snubbing force. In addition, the model takes into account when the wellbore is also tortuous. Fluid viscosity (an important force in the microhole) is also included so we can calculate appropriate surface loads in addition to drag. This study concludes that besides wellbore inclination, curvature, and wellbore torsion, parameters such as wavelength and contact area also influence the results. This paper documents the comparison between the predicted mathematical simulation results with actual data from wells describing the accuracy and applicability of the model. The analysis results and comparison are presented along with three examples (Zhang et al., 2013, “Analytical Model to Estimate the Drag Forces for Microhole Coiled Tubing Drilling,” Society of Petroleum Engineers, Paper No. SPE 163480.).

Worlds First Offshore Horizontal Well Using Jointed Pipe Cemented Frac Sleeve Technology

2022 ◽  
Author(s):  
Shaun Thomson ◽  
Baglan Kiyabayev ◽  
Barry Ritchie ◽  
Jakob Monberg ◽  
Maurits De Heer ◽  
...  
Keyword(s):  
North Sea ◽  
New Technology ◽  
Production Performance ◽  
New Developments ◽  
Coiled Tubing ◽  
The North ◽  
New Novel ◽  
The North Sea ◽  
Reservoir Connectivity ◽  
First Job

Abstract The Valdemar field, located in the Danish sector of the North Sea, targets a Lower Cretaceous, "dirty chalk" reservoir characterized by low permeabilities of <0.5mD, high porosities of >20% and contains up to 25% insoluble fines. To produce economically the reservoir must be stimulated. Typically, this is by means of hydraulic fracturing. A traditional propped fracture consists of 500,000 to 1,000,000 lbs of 20/40 sand, placed using a crosslinked seawater-based borate fluid. The existing wells in the field are completed using the PSI (perforate, isolate, stimulate)1 system. This system was developed in the late 1980s as a way of improving completion times allowing each interval to be perforated, stimulated and isolated in a single trip and has been used extensively in the Danish North Sea in a variety of fields. The system consists of multiset packers with sliding sleeves and typically takes 2-3 days between the start of one fracture to the next. Future developments in this area now require a new, novel and more efficient approach owing to new target reservoir being of a thinner and poorer quality. In order for these new developments to be economical an approach was required to allow for longer wells to be drilled and completed allowing better reservoir connectivity whilst at the same time reducing the completion time, and therefore rig time and overall cost. A project team was put together to develop a system that could be used in an offshore environment that would satisfy the above criteria, allowing wells to be drilled out to 21,000ft and beyond in excess of coiled tubing reach. The technology developed consists of cemented frac sleeves, operated with jointed pipe, allowing multiple zones to be stimulated in one trip, as well as utilizing a modified BHA that allows for the treatments to take place through the tubing, bringing numerous benefits. The following paper details the reasons for developing the new technology, the development process itself, the challenges that had to be overcome and a case history on the execution of the first job of its kind in the North Sea, in which over 7MM lbs of sand was pumped successfully, as well as the post treatment operations which included a proof of concept in utilizing a tractor to manipulate the sleeves. Finally, the production performance will be discussed supported by the use of tracer subs at each of the zones.

Modeling Coiled Tubing Drag Forces - Small Factors Have a Big Impact

2004 ◽  
Author(s):  
A.R. Terry ◽  
Mahesh. Mahajan ◽  
Lance Portman
Keyword(s):  
Coiled Tubing ◽  
Drag Forces

Can developing countries benefit from export promotion?

2005 ◽  
Vol 32 (1) ◽  
pp. 60-80 ◽  
Author(s):  
Xiangkang Yin ◽  
Xiangshuo Yin
Keyword(s):  
Developing Countries ◽  
Social Welfare ◽  
Developing Country ◽  
Analytical Model ◽  
Foreign Exchange ◽  
New Technology ◽  
Export Promotion ◽  
Content Type ◽  
Improve Efficiency ◽  
Efficiency And Social Welfare

PurposeAlthough economic theory generally does not support government intervention in international trade, casual observation shows that many developing countries adopt certain trade policies to promote their exports. The objective of this paper is to answer the question that whether developing countries can benefit from export promotion.Design/methodology/approachThis paper considers a developing country which has to import new technology from the world market to improve its productivity. If it has certain economic rigidities, the country is short of foreign exchange and domestic firms cannot import an adequate amount of new technology. Even if there is no rigidity, domestic firms may not have sufficient incentive to invest in new technology. Therefore, the government can step in to subsidize exports. Through an analytical model, this paper investigates in what conditions the measures of export promotion can stimulate production and employment, and improve efficiency and social welfare.FindingsThis paper analyzes two effects of export promotion: raising the incentive of capital investment and reducing capital goods shortage caused by foreign exchange constraint. These effects might be the economic rationale for developing country governments to promote exports. It is found that export promotion can definitely raise employment and productivity, but whether these measures can stimulate the supply to the domestic market and improve domestic welfare depends on the sufficient and necessary condition given in the paper.Originality/valueEstablishes an analytical model to investigate in what conditions the measures of export promotion such as export subsidies and domestic currency devaluation can stimulate production and employment, and can improve efficiency and social welfare.

scholarly journals Prediction of Wellbore Temperatures During the Scientific Ultra-Deep Drilling Process

2015 ◽  
Vol 8 (1) ◽  
pp. 451-456 ◽  
Author(s):  
Fanhe Meng ◽  
Aiguo Yao ◽  
Shuwei Dong
Keyword(s):  
Drilling Fluid ◽  
Great Influence ◽  
Inlet Temperature ◽  
Drilling Process ◽  
Fluid Viscosity ◽  
Key Factors ◽  
Deep Drilling ◽  
Fluid Displacement ◽  
Temperature Distributions ◽  
Wellbore Temperature

In order to carry out a series of key basic researches, a scientific ultra-deep drilling plan is being undertaken in China. Wellbore temperature is one of the key factors during the drilling process. In this paper, we established a twodimensional transient numerical model to predict the ultra-deep wellbore temperature distributions during circulation and shut-in stages. The simulation results indicate that the cooling effect of drilling fluid circulation is very obvious, especially during the inception phase. Drilling fluid viscosity has great influence on the temperature distributions during circulation stage: the lower the viscosity, the higher the bottomhole temperature. While drilling fluid displacement and inlet temperature have a little effect on the bottomhole temperature. During the shut-in stage, the wellbore temperature recovery is a slow process.

Evolution of Completion Techniques in the Lower Shaunavon Tight Oil Play in Southwestern Saskatchewan

2015 ◽  
Author(s):  
D. J. Schlosser ◽  
M.. Johe ◽  
T.. Humphreys ◽  
C.. Lundberg ◽  
J. L. McNichol
Keyword(s):  
Oil And Gas ◽  
New Technology ◽  
Oil And Gas Industry ◽  
Field Trials ◽  
Gas Industry ◽  
Point Energy ◽  
Horizontal Drilling ◽  
Oil Reserves ◽  
Coiled Tubing ◽  
Open Hole

Abstract The Oil and Gas industry has explored and developed the Lower Shaunavon formation through vertical drilling and completion technology. In 2006, previously uneconomic oil reserves in the Lower Shaunavon were unlocked through horizontal drilling and completions technologies. This success is similar to the developments seen in many other formations within the Williston Basin and Western Canadian Sedimentary Basin including Crescent Point Energy's Viewfield Bakken play in southeast Saskatchewan. In the Lower Shaunavon play, the horizontal multistage completion era began in 2006, with horizontal divisions of four to six completion stages per well that utilized ball-drop sleeves and open-hole packers. By 2010, the stage count capabilities of ball-drop systems had increased and liners with nine to 16 stages per well were being run. With an acquisition in 2009, Crescent Point Energy began operating in the Lower Shaunavon area. The acquisition was part of the company's strategy to acquire large oil-in-place resource plays. Recognizing the importance that technology brings to these plays, Crescent Point Energy has continuously developed and implemented new technology. In 2009, realizing the success of coiled tubing fractured cemented liners in the southeast Saskatchewan Viewfield Bakken play, Crescent Point Energy trialed their first cemented liners in the Lower Shaunavon formation. At the same time, technology progressed with advancements in completion strategies that were focused on fracture fluids, fracture stages, tool development, pump rates, hydraulic horsepower, environmental impact, water management, and production. In 2013, another step change in technology saw the implementation of coiled tubing activated fracture sleeves in cemented liner completions. Based on field trials and well results in Q4 2013, Crescent Point Energy committed to a full cemented liner program in the Lower Shaunavon. This paper presents the evolution of Crescent Point Energy's Lower Shaunavon resource play of southwest Saskatchewan. The benefits of current completion techniques are: reductions in water use, increased production, competitive well costs, and retained wellbore functionality for potential re-fracture and waterflooding programs.

A Mechanistic Model for Wellbore Cleanout in Horizontal and Inclined Wells

2021 ◽  
pp. 1-17
Author(s):  
Rida Elgaddafi ◽  
Ramadan Ahmed ◽  
Hamidreza Karami ◽  
Mustafa Nasser ◽  
Ibnelwaleed Hussein
Keyword(s):  
Shear Stress ◽  
Drag Coefficient ◽  
Mechanistic Model ◽  
Circulation Rate ◽  
Bed Shear Stress ◽  
New Model ◽  
Coiled Tubing ◽  
Water Based ◽  
Improved Model ◽  
The Impact

Summary The accumulation of rock cuttings, proppant, and other solid debris in the wellbore caused by inadequate cleanout remarkably impedes field operations. The cuttings removal process becomes a more challenging task as the coiled-tubing techniques are used during drilling and fracturing operations. This article presents a new hole cleaning model, which calculates the critical transport velocity (CTV) in conventional and fibrous water-based fluids. The study is aimed to establish an accurate mechanistic model for optimizing wellbore cleanout in horizontal and inclined wells. The new CTV model is established to predict the initiation of bed particle movement during cleanout operations. The model is formulated considering the impact of fiber using a special drag coefficient (i.e., fiber drag coefficient), which represents the mechanical and hydrodynamic actions of suspended fiber particles and their network. The dominant forces acting on a single bed particle are considered to develop the model. Furthermore, to enhance the precision of the model, recently developed hydraulic correlations are used to compute the average bed shear stress, which is required to determine the CTV. In horizontal and highly deviated wells, the wellbore geometry is often eccentric, resulting in the formation of flow stagnant zones that are difficult to clean. The bed shear stress in these zones is sensitive to the bed thickness. The existing wellbore cleanout models do not account for the variation in bed shear stress. Thus, their accuracy is limited when stagnant zones are formed. The new model addresses this problem by incorporating hydraulic correlations to account for bed shear stress variation with bed height. The accuracy of the new model is validated with published measurements and compared with the precision of an existing model. The use of fiber drag and bed shear stress correlations has improved model accuracy and aided in capturing the contribution of fiber in improving wellbore cleanout. As a result, for fibrous and conventional water-based fluids, the predictions of the new model have demonstrated good agreement with experimental measurements and provided better predictions than the existing model. Model predictions show a noticeable reduction in fluid circulation rate caused by the addition of a small quantity of fiber (0.04% w/w) in the fluid. In addition, results show that the existing model overpredicts the cleaning performance of both conventional and fibrous water-basedmuds.

Falling Needle Rheometry for General Viscoelastic Fluids

1994 ◽  
Vol 116 (3) ◽  
pp. 619-624 ◽  
Author(s):  
R. Zheng ◽  
N. Phan-Thien ◽  
V. Ilic
Keyword(s):  
Aspect Ratio ◽  
Power Law ◽  
Unit Length ◽  
Cylindrical Tube ◽  
Terminal Velocity ◽  
Fluid Viscosity ◽  
General Technique ◽  
Drag Forces ◽  
Numerical Studies ◽  
Power Law Index

This paper reports theoretical and numerical studies on a flow of a general viscoelastic fluid past a needle placed at the centerline of a cylindrical tube, supplemented by a comparative experimental study. It is shown that the drag per unit length on the needle, which is assumed to be infinitely long, depends on the fluid viscosity only, whatever the first and second normal stress differences may be. This general theory is then specified to obtain solutions for the power-law and the Phan-Thien-Tanner fluids. The power-law fluid results provide a general technique for obtaining flow curves of non-Newtonian fluids from the measured drag forces on falling needles. This is achieved by using KU/R as the effective shear rate, where U is the terminal velocity of the needle, R is the radius of the tube, and K is a function of the power-law index n and the system geometry a/R (where a is the radius of the needle). The effect of the aspect ratio of the needle on the drag force is investigated numerically using a boundary element method for the flow of Phan-Thien-Tanner fluid. Experimentally, a flow curve was obtained for a kerosene solution of PIB (3.39 percent by weight), using falling needles of aspect ratio greater than 40 in a circular cylinder. The result compared well with Carri-Med 50 CS rheometer data.

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