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Collaborating Authors
Drilling Operations
Abstract In November 2016 the Deep Exploration Technologies Cooperative Research Centre (DET CRC) launched the RoXplorer, a coiled tubing (CT) drilling rig for greenfields mineral exploration, delivering a platform for low-cost, rapid, safe and environmentally-friendly drilling. The launch represented an important technical milestone in the development of CT drilling for mineral exploration and has been complemented by a series of very successful field trials in the first half of 2017 The paper presents CT technology and its application for mineral exploration drilling. The three key challenges for CT drilling in mineral exploration are coil durability, drilling hard rocks with low weight-on-bit and sample fidelity. Results for mineral exploration CT-drilling field-trials in the consolidated cover rocks of South Australia and the unconsolidated cover rocks of the Murray Basin in Victoria are presented and outline how each of these challenges was overcome. The outcomes confirm the promise of this cheaper regional prospecting approach to mineral exploration drilling. The results of assay samples of the CT drilling cuttings are remarkable; the assay samples from the CT drilling at Port Augusta trial matched those of diamond drill core from an adjacent hole.
- Geology > Mineral (1.00)
- Geology > Rock Type > Igneous Rock (0.48)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Oceania > Australia > Victoria > Murray Basin (0.99)
- Oceania > Australia > South Australia > Murray Basin (0.99)
- Oceania > Australia > New South Wales > Murray Basin (0.99)
- Well Drilling > Drilling Operations > Coiled tubing drilling (1.00)
- Well Drilling > Drilling Equipment (1.00)
- Well Completion > Completion Installation and Operations > Coiled tubing operations (1.00)
Abstract Oil and gas wells are drilled with horizontal and multilateral architecture to improve reservoir contact and maximize production. To evaluate the performance of these wells, coiled tubing (CT) and Wireline (WL) conveyance are routinely used. CT inherently have many technical issues such as lock-up. The WL cannot reach the target depth. To address these challenges, the oil industry introduced well tractors that are combined with CT and WL to offer a significant improvement in well accessibility for all types of open- hole horizontal wells by providing extra pulling force to pull CT and WL all the way to target depth. The objective of this article is to evaluate most of the well tractor technology used in logging and stimulation operations. Moreover, the development of a new slim tractor with improved gripping and pulling force with ability to pass through restrictions in electrical submersible pump (ESP) is presented. This study can help identify areas of improvement for tractor capabilities in future operations.
- Asia > Middle East > Saudi Arabia (0.46)
- North America > United States > Texas (0.28)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Completion Installation and Operations (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Production and Well Operations > Well Intervention (1.00)
Abstract The coiled tubing (CT) industry continues to operate in deeper and higher pressure wells and in more challenging environments, thereby extending the operating envelope for the service worldwide. CT operations for cement milling provides a safer, faster, and more economical solution, but achieving the desired results in a high pressure, high temperature (HPHT) offshore environment using corrosive brine as the milling fluid is challenging. This paper describes various challenges and customized remedies for a cement milling operation in an HPHT well with high-density brine, which made milling challenging because of limitations on pumping rates, low viscosity, and fluid corrosiveness. This offshore gas well had a bottomhole static temperature (BHST) of 400 °F and reservoir pressure of 12,000 psi, with a completion of 9-5/8 in. casing from the surface and a 3-1/2-in. liner hanging from 4,606 meter measured depth (mMD). A 1.75-in. outer diameter (OD) CT string was used to accommodate the internal diameter (ID) restriction of the liner. The allowable pumping rate in the 1.75-in. CT was restricted as a result of pipe friction and low viscosity of milling fluid; however, higher annular velocities were needed to lift the cuttings from the wellbore. To overcome this, additional pumping was performed from the annulus of the 9-5/8-in. section. A positive-displacement, metal-on-metal motor was selected over various types of motors. This paper provides details about best practices, including the selection of brine-compatible elastomeric seals, severe corrosion observed on the motorhead assembly (MHA), and redressing of MHA after each run. It also includes details about laboratory tests performed to identify a suitable viscosifier and corrosion inhibitor, as well as the optimum rate of penetration (ROP) and weight on bit (WOB) to avoid large cuttings, surface-fluid handling, and filtering arrangements. Based on precise tool selection, including power section, bearing section, and corrosive-brine-compatible motor seals, as well as design parameters, such as ROP, annular fluid velocity, particle size, and equivalent circulating density (ECD) under the operating envelope, cement milling of 217 m of cement was completed successfully in an overbalanced condition with no health, safety, and environment (HSE) related issues. Selecting the correct milling motor and mill plays a crucial role in any milling job. Several operational challenges, such as excessive corrosion at a minimum MHA ID, pitting on bottomhole assembly (BHA) components and erosion on ball seats, erosion, and degradation of elastomeric seals at a BHST of 400 °F, were observed. These adverse effects were avoided with engineering controls. The methods used, tool selection, and customized design helped the operator to find a solution for milling a cement plug in an HPHT well with zinc bromide (ZnBr2) brine, which resulted in reduced rig time and avoided the side tracking of the well. The lessons learned, methods, and best practices described in this paper can be used in a similar application worldwide, which can help to minimize issues related to service quality and HSE.
- North America > United States > Texas (0.46)
- Asia > India > Andhra Pradesh (0.28)
- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Fluids and Materials (1.00)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- (6 more...)
Abstract This paper describes a recent Directional Coiled Tubing Drilling (DCTD) job that was completed for an independent operator in the Appalachian Basin. The objective was to access target zones identified adjacent to a recently drilled, vertical well using a lateral sidetrack. The target thickness was around 15ft so accurate depth control was critical. It was also considered essential that the entire reservoir section be drilled underbalanced to minimise formation damage. The challenge was to deliver a productive horizontal sidetrack in an effective and cost-efficient manner. The field development strategy required costs to be kept to a minimum, but the use of high-tech equipment was essential to delivering the production improvements. A 3.2 inch DCTD Bottom Hole Assembly (BHA) and a specialised DCTD engineering software package were enabling technologies. A multi-disciplinary approach was adopted to plan and execute the sidetrack. This approach required inputs to the planning process from all stages in delivering the well, which included: 3D seismic, well trajectory planning, drilling engineering, completions. This project was ultimately successful in that a dry hole was re-entered and sidetracked to create a productive well, thereby validating the technology and multi-disciplinary approach of the team. The lessons learned from this operation can be used to optimise the planning of future wells and maximise the value of re-entering marginal wells and fields.
- North America > United States > West Virginia > Appalachian Basin (0.99)
- North America > United States > Virginia > Appalachian Basin (0.99)
- North America > United States > Tennessee > Appalachian Basin (0.99)
- (7 more...)
- Well Drilling > Well Planning > Trajectory design (1.00)
- Well Drilling > Pressure Management > Underbalanced drilling (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- (3 more...)
Abstract As a result of improved drilling and completion techniques, an increasing number of wells worldwide utilize multilateral systems to minimize the number of surface penetrations required to maximize reservoir contact. However, these systems increase the complexity, which in turn introduces new failure modes and challenges related to inspection of erroneous completions. The scanning range and measurement capabilities utilizing ultrasound imaging techniques provide a new solution for well diagnosis of multi-lateral completions. Several attempts to enter the upper lateral of a multi-lateral well operated by a major oil company in Alaska, USA had been unsuccessful. Different technologies were attempted to diagnose the problem but no conclusive results were obtained. In May 2017, an ultrasonic imaging technique based on medical ultrasound imaging was used to inspect the Lateral Entry Modules (LEMs). This paper presents the data collected by an ultrasound downhole scanner demonstrating a novel method for diagnosing multi-lateral wells. The ultrasound downhole scanner utilizes established technology applied in medical ultrasound imaging (e.g. Angelsen 2000) to obtain images and measurements of downhole completion components. A 288 element, 3.3MHz circumferential ultrasound transducer array combined with electronic beamforming allows the flexibility to optimize image quality for different tubing sizes with no moving parts. The transducer operates in pulse-echo mode. Logging is performed dynamically with images obtained real-time. In 2011, the scanner was used to measure damages in sand screens (Hyde-Barber et al.) and has since 2009 been used to image and measure downhole completion components worldwide. The possibly defective LEM was investigated by the scanner. A reference scan of a fully functional LEM in the same well was also made and the results from the two compared. The ultrasound data, visualized both as 2D grey-scale images and 3D-rendered images, clearly show that the upper LEM assembly was not properly aligned with the window of the lateral. Thus, explaining the past unsuccessful attempts to enter the completion. Measurements were made directly on the ultrasound images to document the findings. The results from the survey helped the customer to understand the situation of their well and gave information which was valuable for the decision making process.
- North America > United States > Texas (0.46)
- North America > United States > Alaska > North Slope Borough (0.29)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Sand Control (1.00)
- Well Completion > Completion Installation and Operations (1.00)
- (2 more...)
Abstract When configuring tractor assemblies for highly deviated or horizontal conveyance, the tractor power required to deliver the conveyed passenger tool to the target well depth is determined by the weight of the deployed cable and payload, the tortuosity of the well trajectory, and the extent of the target depth. Until now, the tractor toolstring needed to be configured accordingly before being run in hole. Conveyance speed is compromised for the maximum power requirements expected to ensure the tractor is capable of delivering the payload to the target depth. Having the ability to adjust the power versus speed on command allows the tractor to be optimized to deliver the highest speed in the earlier parts of the well where maximum power is not required. In the deeper portions, or where the well becomes more tortuous, the tractor can be controlled to provide maximum power and ensure the target depth is achieved. Real time control delivers considerable reductions in total conveyance operating time. This is achieved by independently controlling the various drive sections to deliver the optimum speed/power configuration per well section. There have been more than seventy jobs completed to date utilizing selective functionality across a variety of US land tractor conveyance operations. The jobs have been performed with a range of electric line companies while servicing numerous exploration and production (E&P) operators. Examples include record wells with lateral lengths requiring over 15,000 ft of tractoring. The application of this in-well, real-time adjusted optimization has resulted in tractor conveyance time savings of over 40%. In addition to the efficiency gains, there has also been a reduction in operational risk due to less time spent in hole tractoring. Selective tractor functionality is commercially available from one provider at the time of writing, but it is quickly setting standards for all tractor conveyance providers.
- Well Drilling > Well Planning (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- (4 more...)
Abstract The paper provides an update on recent advances for, and summarizes global experiences with, dendritic acidizing methods, aka acid tunneling. The scope of the paper includes both Coiled-Tubing (CT) deployed and non-CT methods, and discusses process limitations, candidate selection criteria, job design factors, operational learnings, risks, and surveillance requirements and opportunities. The paper contains a comprehensive review of published information for three different tunneling methods and relevant information for several other tunneling methods. The literature information is supplemented by, depth, temperature, and pressure records for the three processes which are discussed in detail. Execution factors such as logistics required, length of time required, and volumes of acid and other fluids used are also compared for three methods. Previous papers have focused on only one of the methods, whereas the authors will discuss acid job optimization, process risks, and surveillance requirements for multiple acid tunneling methods in substantially greater depth than have past authors. The three methods detailed in the paper are all viable but may have different niches. Differences in the job counts for the different methods are easily explained by differences in process vintages, execution speeds, and depth limitations. Previous optimization efforts were focused on tunnel creation but not acid job effectiveness in terms of the wormholes generated adjacent to the tunnels; however, some progress is now being made in that regard. There are differences in the processes regarding pushing or pulling the jetting nozzles into the tunnels, and differences in resulting tunnel trajectories. Pre-job caliper data are more critical for one of the processes than for the others, and there are significant differences in ability to measure or control tunnel direction. The tunneling tools have different sizes, but when tool size alternatives are available, the larger tool sizes offer no clear advantages to the operator. Useful risk mitigation measures are also discussed in the paper. The paper includes a comprehensive bibliography to facilitate further examinations of the technology alternatives by other petroleum industry professionals.
- Asia (1.00)
- North America > United States > Texas (0.46)
- North America > United States > California > Kern County (0.28)
- North America > United States > California > San Joaquin Basin > Midway-Sunset Field > Webster Formation (0.99)
- North America > United States > California > San Joaquin Basin > Midway-Sunset Field > Monterey Formation (0.99)
- North America > United States > Alaska > North Slope Basin > Kuparuk River Field > Kuparuk Field (0.99)
- (3 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Completion Selection and Design > Completion equipment (1.00)
- Well Completion > Acidizing (1.00)
- (2 more...)
Laboratory Evaluation of a Novel Metal Surface Treatment for Coiled Tubing Friction Reduction in Extended-Reach Wells
Elliott, K. J. (NOV Quality Tubing) | Livescu, S.. (Baker Hughes, a GE Company) | Baker, Hughes (Baker Hughes, a GE Company) | Yekta Ganjeh, K.. (Essential Coil Well Services) | Li, Y.. (NOV Quality Tubing)
Abstract In the past few years, operators have been increasing the lateral lengths of horizontal wells to maximize the reservoir contact and production rates. However, the frictional forces between the coiled tubing (CT) and casing in those long lateral wells also increase, limiting the ability of conventional CT sizes to reach the end prior to lock-up occurring. Technologies such as lubricants, vibratory tools and tractors are usually used to extend the CT reach. However, the downhole performance of some of these friction-reducing technologies is sometimes unpredictable and inconsistent. In addition, with the current industry's trends to lower the overall intervention costs, lubricants may be considered too expensive in long laterals. This paper reports on the laboratory evaluation of the friction-reduction performance of a novel CT surface treatment. This surface treatment has been proven to be effective at reducing the frictional forces by altering the CT surface finish. After the treatment, the CT surface is smoother and has micron-size dimples that work as small reservoirs, preventing a lubricant from being easily washed off the CT surface. The new metal surface treatment was applied to several CT samples. The friction between the treated CT samples and various actual casing samples was studied in a laboratory on a linear friction apparatus. This instrument is specifically designed to measure the coefficients of friction between CT and casing at downhole conditions, such as with or without fluids relevant to coiled tubing operations and at temperatures as high as 100°C. Additionally, laboratory tests were performed to determine the ability of the treated and un-treated CT samples to retain lubricants when sliding on the casing surfaces. Currently, there are two main operational challenges of using lubricants for reducing the CT friction. First, to reduce the lubricant volume in long laterals, and therefore the intervention costs, many operators choose to pump lubricant slugs instead of pumping the lubricant continuously. However, most of the lubricant is consumed inside the CT, and only a small lubricant amount adheres to the outside CT and casing surfaces where the friction needs to be reduced. Secondly, even if the lubricant coats the outside CT surface, there is a risk of being quickly washed off, unless new lubricant is pumped continuously. The laboratory testing results obtained from this study have shown a reduction of the coefficients of friction after the CT metal surface treatment. These results prove the friction-reduction potential of manufacturing a CT with the new treated surface for extending the CT reach with or without friction-reducing technologies such as lubricants, vibratory tools and tractors. The advantage of utilizing the new CT metal surface treatment is that a lubricant remains longer in the micron-size pores on the CT surface and reduces the CT friction more consistently. The novel idea in this paper encompasses the fact that the CT metal surface treatment has the potential to reduce the CT friction by itself and further in combination with friction-reducing technologies such as lubricants, vibratory tools or tractors. The new CT surface is smoother and has micro-pores that can prevent a lubricant from being easily washed off the CT surface. The laboratory tests with the new CT samples have shown reduced coefficients of friction when comparing to conventional CT coupons with un-treated surfaces.
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Completion Installation and Operations > Coiled tubing operations (1.00)
- Production and Well Operations (1.00)
Abstract "Run in hole", "stop CT", "pickup", "drop pumps"… All common commands heard in the control cab during a coiled tubing plug drillout (CTDO). What drives the decision making process and what information has been processed to arrive at such a conclusion? During a coiled tubing (CT) operation, many parameters are being acquired including pump rate, pressures, weights and speeds, and the success of the operation relies on how the supervisory personnel interpret this data and advise on next steps. At the end of the job, if lucky, this crucial data is archived in the catacombs of the well file on some network server. What if instead, this information was analyzed to detail the operation, develop performance metrics to help understand why the results were what they were, and ultimately provide guidance for future operations? This paper discusses an algorithm developed to support analysis and a philosophy of job review that has been utilized to robustly process a rich, continuous and widely available CTDO data set.
- Well Drilling > Drilling Operations (1.00)
- Well Completion > Completion Installation and Operations > Coiled tubing operations (1.00)
- Management (1.00)
Abstract Plug-and-perf multizone fracturing remains a dominate completion method in the Haynesville shale. Removing the composite frac plugs (CFP) utilizing coiled tubing (CT) remains a challenging operation with increased risks due to extreme well environments. Operations completed using older, conventional methodologies increase the likelihood of stuck CT events. These stuck pipe events add considerable cost to the completion through fishing, lost production time, or worse, loss of the entire well. In one such instance while milling CFPs, the downhole tools seized resulting in loss of circulation, subsequently leading to a stuck in hole event. Wireline severing tools cut the pipe in the vertical section, leaving over 4,500 ft of 2 in. CT in the lateral. Removing the CT fish without damaging the formation was paramount to the long-term profitability of the well. Conventional fishing methods were considered, but unfavorable economics in addition to the risk of formation damage lead to the selection of a hybrid approach combining wireline, snubbing, slickline and CT. The fish was successfully latched using a snubbing unit, providing a conduit for 1-¼ in. CT to convey a severing tool to free the larger coil in the lateral section. This enabled the continuous removal of the 2 in. CT under live well conditions, saving over 4 million dollars and 55 days compared to conventional techniques. Following the stuck pipe event, a complete change in the drillout procedure was implemented, increasing efficiency while minimizing the risk of a repeat event.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.36)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play (0.36)
- North America > United States > Texas > Haynesville Shale Formation (0.99)
- North America > United States > Louisiana > Haynesville Shale Formation (0.99)
- North America > United States > Arkansas > Haynesville Shale Formation (0.99)