Bicentric Milling Approach Enables the Recovery of the Horizontal Section of an Unconventional Well in Turkey

2021 ◽  
Author(s):  
Ernesto Franco Delgado ◽  
Felix Jahn ◽  
Liam Weir ◽  
Brian Bruce ◽  
Nestor Carreno

Abstract During the completion phase of an unconventional well in Turkey, casing deformation represented a challenge to the operator and Coiled Tubing (CT) service provider due to the potential loss of almost 70% of the horizontal section. The deformation obstructed the path to continue the milling the remaining plugs. The implementation of bicentric mills and Multi-Cycling Circulation Valve (MCCV) incorporated in the milling assembly allowed efficient recovery of the horizontal section. The tubing condition analysis done by the engineering team showed that symmetric mills would not be beneficial. Conformance tubing was not an option. Bicentric milling approach was deemed the most viable solution. This approach consists of using offset mills where rotation causes the cutting head to cover an area larger than the mill's frontal face. However, this approach could lead the CT pipe getting stuck due to big junk left. The use of a MCCV, limiting the number of milled plugs, and performing a fishing run between milling runs were key to the success of the bicentric milling approach. The Turkish well was completed with ten stages isolated by nine aluminum plugs. During the fracturing of stage seven, an abnormal pressure drop was observed while keeping the same pump rate, indicating possible casing damage. After all the stages were fractured, the CT proceeded to mill the plugs using a 4.63-in Outside Diameter (OD) mill. After three plugs were milled, an obstruction was detected, indicated by frequent aggressive motor stalls at the same depth. A tapered mill was run to perform a tubing conformance, and after several hours of unsuccessful penetration, the tool was recovered. At the surface, the tool showed signs of wear around 4.268 in. A 4.0-in OD mill was used to drift this section, and it passed free. An analysis of both the plug anatomy and the casing condition was done to determine the most viable solution. A 4-in OD bicentric mill was designed to pass across the restriction with an adjusted eccentricity to allow higher contact area. Three bicentric milling runs were made with the limit of a maximum of two plugs per run to avoid a CT stuck situation due to the larger cuttings as a result of the mill's asymmetry. The sparsity of information on using bicentric mills for plug milling required research into unpublished practices for such scenarios. This paper documents bicentric milling approach, the use of offset mills, and the mitigation measurements taken during this project to avoid a stuck situation due to large debris generated.

2022 ◽  
Author(s):  
Mikhail Klimov ◽  
Rinat Ramazanov ◽  
Nadir Husein ◽  
Vishwajit Upadhye ◽  
Albina Drobot ◽  
...  

Abstract The proportion of hard-to-recover reserves is currently increasing and reached more than 65% of total conventional hydrocarbon reserves. This results in an increasing number of horizontal wells put into operation. When evaluating the resource recovery efficiency in horizontal wells, and, consequently, the effectiveness of the development of gas condensate field, the key task is to evaluate the well productivity. To accomplish this task, it is necessary to obtain the reservoir fluid production profile for each interval. Conventional well logging methods with proven efficiency in vertical wells, in case of horizontal wells, will require costly asset-heavy applications such as coiled tubing, downhole tractors conveying well logging tools, and Y-tool bypass systems if pump is used. In addition, the logging data interpretation in the case of horizontal wells is less reliable due to the multiphase flow and variations of the fluid flow rate. The fluorescent-based nanomaterial production profiling surveillance technology can be used as a viable solution to this problem, which enables cheaper and more effective means of the development of hard-to-recover reserves. This technology assumes that tracers are placed downhole in various forms, such as marker tapes for lower completions, markers in the polymer coating of the proppant used for multi-stage hydraulic fracturing, and markers placed as fluid in fracturing fluid during hydraulic fracturing or acid stimulation during bottom-hole treatment. The fundamental difference between nanomaterial tracers production profiling and traditional logging methods is that the former offers the possibility to monitor the production at frac ports in the well for a long period of time with far less equipment and manpower, reduced costs, and improved HSE.


2012 ◽  
Vol 482-484 ◽  
pp. 667-673
Author(s):  
Jun He ◽  
Hui Juan Dong ◽  
Ren Bing Liu ◽  
Hong Liang Pan ◽  
Yong Cai ◽  
...  

Due to the tube is suffering deformation and damage by a series of factors, such as external force, chemical corrosion etc. The production of oil and the oil wells' service life is directly affected. As the number of casing damage is increasing year by year, the casing damage especially the casing inspection of key layer has become the focus of oilfield development process. The height of critical layer is usually about 5m, so the author puts forward that it's much more accurate to use the distributed FBG sensor as the short distance measurement method to guarantee the precision, and coupled with the traditional temperature compensation method of FBG strain monitoring. With a special installation process and the application of 40-Caliper logging tool to get the FBG' s azimuth, we get real-time strain data in the process of installing casing pipe. This paper analyzes the variation of value of the casing strain in each installation stage, the theoretical calculation results are basically the same with the data got by XMAC logging method. This proves the reliability of the distributed casing deformation monitoring system which is specifically used for the key layer of casing annulus.


2021 ◽  
Vol 73 (01) ◽  
pp. 23-27
Author(s):  
Stephen Rassenfoss

The snarled red lines on the chart look more like a plate of spaghetti than a source of fracturing insights. It looks like a meaningless mess, which is generally how the ups and downs of difficult stages are viewed. To Adam Hoffman, a completion engineer for Chesapeake Energy, those 47-stages-worth of data look like a valuable opportunity. “We see so many stages with so many odd spikes and drops or chatter. We chop it off and say that was an odd stage. In my mind when we are looking at all those stages, we should wonder, ‘what was that pressure spike telling us,’” he said. That curiosity became a research project after Chesapeake encountered a spate of blockages in recently fractured Eagle Ford wells. The investigation into the cause of the casing damage led to a collaboration with Well Data Labs to look for connections between pressure changes and what is happening in the wells. Based on hundreds of stages of data from 19 wells fractured in the Eagle Ford, and later in the Powder River Basin, they reported finding a distinctive pressure signature that provides a reliable, but not foolproof, guide to when casing damage is likely. Well Data Labs has automated the search for those signatures as it looks for the meaning of the terabytes of fracturing data in this overwhelming number of seemingly random, squiggly lines. The oilfield data and software company is working on ways to monitor changes in the fracturing-fluid chemistry, the proppant intake into perforations, and an explanation for the pressure spikes seen before the pressure falls, said Jessica Iriarte, research manager at Well Data Labs. The troubleshooting and pressure analysis were covered in paper SPE 201484 presented at the 2020 SPE Annual Technical Conference and Exhibition (ATCE). It described how engineering trouble-shooting revealed that geological stresses were the likely source of problems in one case, and faulty pipe in the other. It followed up with data analysis, which used machine learning to identify distinctive patterns that provide an early warning of what is happening in the well faster and more objectively than a completion engineer studying the chart. Based on the troubleshooting, Chesapeake made changes that largely eliminated those costly problems. But it was also a costly learning process. In the Eagle Ford, they identified the underlying problem by investigating why multiple coiled-tubing runs were blocked while they were trying to drill out plugs after fracturing. When that happens, Hoffman said, “it can mean a week lost working past it.” Failure to drill out a plug can block access to the productive rock further down the lateral. A reliable automated treating-pressure analysis in the daily report could alert the completion team to problems while fracturing is in progress. They could then make adjustments on later stages and create a plan to limit the time lost when drilling out plugs on stages where they are likely to encounter tight sections.


2021 ◽  
Author(s):  
Edward Jason Wheatley ◽  
Gladwin Correia ◽  
Samhar Adi ◽  
Nestor Molero ◽  
Cremilton Silva ◽  
...  

Abstract Maximizing reservoir contact through extended-reach and mega-reach wells has become a prevalent field development strategy for major offshore operators in the Middle East. This is especially true for the giant oilfield "A", where drilling targets go beyond 40,000 ft. measured depth (MD), with MD/TVD ratios in excess of 4.5:1. Such challenging horizons call for a detailed re-evaluation of well interventions. In 2019, the well surveillance program in the field A required intervention in a mega-reach well with a MD over 35,500 ft. and 4.5:1 MD/TVD ratio. This reach was unthinkable only a few years ago but has been made possible thanks to several recent key technological advancements, such as coiled tubing (CT) equipped with optical fiber and new CT hydraulic tractors, proactive and detailed planning during the drilling phase, the development of highly engineered CT string designs, surface equipment upgrades, and accurate software modeling. The target well is an oil producer with horizontal section beyond 23,000 ft., completed with 6 5/8-in. pre-perforated liner and 23 swellable packers placed across the 8 1/2-in. open hole section. A multiphase production logging tool was selected to assess the production profile along its horizontal drain. With a target depth beyond the reach of conventional wireline, CT equipped with optical fiber emerged as the optimum solution to facilitate reach and overcome the weight and pumping limitations of wired CT. A comprehensive CT reach modeling exercise compared the performance of several 2-in. and 2 3/8-in. CT string designs and identified operational requirements and reach gains from CT hydraulic tractors. As a result, an engineered 2-in. CT tapered string of near 36,700 ft. was developed, capable of being equipped with optical fiber line, while delivering the required flow rate and differential pressure to the CT hydraulic tractor without compromising any operational safety margin. At the time of manufacturing, this was considered the longest CT string ever produced and fitted for downhole telemetry. The operation itself set new records for well interventions in mega-reach wells, with a CT reach above 35,500 ft. MD, including a hydraulic tractoring footage over 15,650 ft. MD with spaced slugs of chemical friction reducer. This case study explains how to develop a safe, robust, and effective solution to mega-reach well challenges using the CT-conveyed optical fiber telemetry technology in one of the deepest wells in the field A, setting a new global record in CT reach. The lessons learned are now the reference for other operators in the Middle East and across the globe for performing interventions in wells that continue to be stretched in its extended reach. It also depicts why telemetry through optical fiber is key to the success of such projects and provides an overview of technology needs for the future of mega-reach well developments.


2019 ◽  
Vol 12 (24) ◽  
Author(s):  
Xuangang Meng ◽  
Weijia Wang ◽  
Zhenzhen Shen ◽  
Jiangyong Xiong ◽  
Heng Zhang

AbstractMultistage stimulation operation using plug and perf technique is the main development mode in domestic shale gas play. Because of the particularity of well trajectory, well geometry caused by rapid drilling operation in shale gas wells, the residual plug debris after plug milling, the complexity of multiphase flow in horizontal section, etc., it is difficult for conventional production logging to meet the needs of shale gas wells. However, a number of shale gas wells need to be evaluated in the effects of well drilling and completion and fracturing, providing the guidance for the next fracturing design, so the production logging via coiled tubing fiber optic infrastructures (FSI) can satisfy the needs of shale gas wells, really reflect water holdup and gas holdup in different fracturing stage, and effectively evaluate fracturing effect of each stage.


2019 ◽  
Author(s):  
Humoud Almohammad ◽  
Hazim Ayyad ◽  
Alaa Sultan ◽  
Nitin Rane ◽  
Khaled Abdulrahim ◽  
...  

2021 ◽  
Author(s):  
Courtney Payne ◽  
Wilson Yip ◽  
Sergio Rondon Fajardo ◽  
Ryan Leroux

Abstract Cleanouts and milling make up most of the common coiled tubing (CT) operations around the globe. The objective of each is to remove debris from a wellbore, such as sand, scale, cement, or fracture plugs, to promote an unobstructed flow path for fluids. For decades, operators and service companies have focused heavily on methods to optimize removal of debris through the development of specialized tools, fluids, techniques, and predictive models. These are coupled with wellsite equipment digital acquisition systems to capture CT behavior, pump rates, and chemical additive rates; very little attention has been given to the rates of the fluid and solids being returned to surface. The composition and quality of fluids being pumped into the well are often well characterized, and the pump rate is recorded digitally to the second. By contrast, information on the fluid being returned is frequently limited to intermittent, manual surveys of the flowback tank fluid level that often go unrecorded. Fluid samples are rarely analyzed, even by inexact measurements, to provide feedback to the predictive model. This results in a missed opportunity to optimize the operation as well as to recognize and respond to undesirable trends and actions in real time. This paper describes a simple digital acquisition system developed and implemented in the field to digitally record, plot, and monitor critical wellsite parameters including flowback rate, solids returns, annular velocities, and downhole Reynolds numbers. The system provides a real-time visual aid to observe the direct impact that operational decisions have on cleanout efficiency and the opportunity to correct and optimize the cleanout operation. Furthermore, the system offers the opportunity to rapidly recognize and respond to unexpected trends such as a gradual or sudden loss in return rate or a decrease of solids returns which could rapidly result in serious consequences such as a stuck-pipe situation.


2021 ◽  
Author(s):  
Mohamed Larbi Zeghlache ◽  
Hermawan Manuab Ida ◽  
Abderrahmane Benslimani ◽  
Rajesh Thatha

AbstractWireline logging in a complex well profile, such as extended reach drilling (ERD) wells, presents many challenges for conveyance and data quality. Traditional pipe conveyed logging (PCL) or coiled tubing (CT) are prohibitive in terms of rig time, operational complexity and cost. Alternatively, tractor conveyance is limited by the available force in long laterals. Tools and accessories create higher friction and might jeopardize tool position in the horizontal section. Consequently, both data quality and reaching total depth are compromised. This paper details an innovative deployment technique using oriented wheels to address these challenges.The new centralizing system, comprised of bespoke wheeled carriages, takes a holistic approach to tool conveyance, reducing drag while ensuring optimum sensor orientation. Tool position is achieved through management of tool center of gravity, relative to the wheel axes. The idea of "centralizing by decentralizing" uses the wheeled carriages instead of bow spring centralizers. An eccentered counterweight is included to ensure the proper orientation of the logging sensors.In addition to improving data quality with proper centralization, the wheels minimize friction and the required force to push the toolstring when combined with a tractor. This enables the toolstring to safely and efficiently reach the well bottom and avoid multiple attempts and associated downhole failures. In the planning phase, calibrated software simulation parameters for this technique help to predict free-fall depth and required tractoring force.The wheeled carriages were deployed in an ERD well for cement evaluation across a 9-5/8" casing and could reach a world record of 85° by gravity. The reduced friction and optimized tool position resulted in higher tractor force margins; and so a net gain in the overall tractoring distance. Also, the low drag and surface tension enabled a sufficient pull capacity with a minimum drive combination. For data acquisition, this deployment enabled a minimum eccentricity, resulting in better cement evaluation data quality and reduced uncertainty related to interpretation. In addition to these benefits, a tangible and direct savings of rig time has improved safety, operational efficiency and well delivery KPIs. Oriented wheels with tractors were deployed in other challenging environments and showed consistent and reliable results.This innovative technique can be deployed in both open-hole and cased-hole with fitted design depending on the borehole size, well profile and complexity of the toolstring configuration.


Sign in / Sign up

Export Citation Format

Share Document