Raman to continue research on diamonds

Matrix acid stimulation in carbonate formations can often be vital to remove formation damage post drilling and achieve a more uniform production profile. Reaching well total depth (TD) is critical for an effective treatment in extended reach wells (ERWs) completed with an electrical submersible pump (ESP). The ESP completion with minimum restriction of 2.44-in. limits the coil tubing (CT) and downhole tools size. Hydraulically powered CT tractors are an ideal solution to pull the CT to TD (Saiood et al. 2018). The completion minimum restriction only allows for 2-in. CT with 2-1/8-in. OD hydraulically powered CT tractors and a maximum pulling force of 3,200 lbs. Pre-job CT design-aided simulations predicted the 2-in. CT size and a 2-1/8-in. CT tractor would not reach well TD due to unfavorable trajectory and therefore potentially jeopardizing a successful stimulation treatment. An alternative method is to utilize 2-7/8-in. CT combined with a 3.5-in. hydraulically powered tractor to conduct matrix acid stimulation prior to installing the upper ESP completion with restricted ID. This alternative arrangement allows for a maximum pulling force of 9,200 lbs, ensuring a greater reach in ERWs and effective treatment. It also tolerates higher pumping rates with 2.875in. CT (up to 5 bbl/min as compared with 2 bbl/min for 2-in. CT), reducing the exposure time of acid on surface, reaching optimum rates faster creating favorable wormholes in the carbonate formation and reducing the pumping operation time by up to 50%. Matrix acid stimulation is then completed with the drilling rig still in position post drilling operations. Thereafter, the upper ESP completion with restricted ID is installed. This engineered solution provides an alternative for CT interventions in extended-reach horizontal wells featuring completion restrictions, where the main challenge is to maximize the reach for optimum stimulation. The approach of combining the 3.5-in. hydraulically powered tractor with 2.875-in. CT pipe successfully enabled effective stimulation of the openhole section to a 27,000-ft. TD in a challenging downhole environment.

The lateral reach and residual bottom hole assembly (BHA) loads in extended-reach wells strongly depend on the coiled tubing (CT) mechanical friction. Detailed CT friction modeling becomes crucial in the pre-job planning stage to ensure successful job predictability. However, current numerical simulators consider constant coefficients of friction (CoFs) that are determined from similar operations without taking into account the effects of the operational and downhole parameters on the CoF for a specific operation. This study outlines the modeling of CT friction force, CoF, and axial BHA loads depending on the operational and downhole parameters when a fluid hammer tool is used. Recent theoretical, laboratory, and field data have established how CoF depends on the downhole parameters (Livescu and Watkins 2014; Livescu et al. 2014; Livescu and Craig 2015). Previously, these effects have not been considered in the CT numerical models, leading to significant CoF differences among available commercial simulators. For instance, the default CoFs in the current pre-job simulations for cased holes, when no lubricant or friction reducing tools such as fluid hammer tools and tractors are used, vary between 0.24 and 0.30 or even higher. This makes it extremely difficult to consistently evaluate and compare the friction reduction effects of lubricants, fluid hammer tools, and tractors in extended-reach wells, especially when the field operator may be consulting with several service companies utilizing different commercial force modelling software. This study presents the CT force matching and fundamental physics based on modeled fluid forces, including radial forces, drag forces, and most importantly pressure forces on the CT friction forces due to fluid hammer tools. Extending the Method of Characteristics, regularly used for studying pressure pulses in straight pipes, the Perturbations Method also accounts for the helical shape of the CT. The new CT fluid hammer model is validated against laboratory data. This rigorous method for calculating the axial BHA load and reduced CT friction force due to radial vibrations can be easily implemented in currently available tubing force analysis (TFA) software for CT operations. This novel approach, which uses detailed CT mechanical friction modeling to take into account parameters such as temperature, internal pressure, pumping rate, etc., improves predictions for CT reach in lateral wells. These findings broaden the current industry understanding of the CT mechanical friction modeling in extended-reach wells and show benefits for the industry when considering variable friction modeling in commercial CT simulators.

Young Technology Showcase As oil reserves mature around the world, oil companies look to improve the recovery of existing assets and to tap into unconventional reserves such as shale gas and tight gas. Coiled tubing (CT) and jointed tubing (JT) have progressed to larger sizes and premium material grades to adapt to these new and extended applications. However, some situations, such as long horizontal or ultradeep wells, remain where either the CT or JT is unable to provide the required reach efficiently and safely. Combining CT and JT can bring the flexibility of CT to extended-reach horizontal wells. Typical well intervention operations present several challenges, including equipment and reel availability, transportation issues, achievable flow rates, and the ability to reach the target depth of the well. CT is prone to sinusoidal buckling and eventual lockup in deviated and horizontal wells. This means that friction-reducing agents or mechanical aids such as tractors may be necessary to reach target depths. Smaller CT reduces the flow rate that can be achieved and requires higher horsepower to overcome fluid friction. JT, on the other hand, is larger and heavier than CT but requires constant making and breaking of connections during trip in and trip out, which requires redundant safety measures and reduces the effectiveness of downhole operations. In shale plays, operators have determined that laterals in excess of 10,000 ft and more than 30 fracturing stages are necessary to maximize production and achieve the desired return on investment. These wells are challenging to complete using only CT. PowerReach Service Boots & Coots, a Halliburton service, developed PowerReach, which combines CT and JT to form a hybrid string that offers the best of both. The resulting string allows for greater depth for long horizontals, high flow rates when using larger CT, and a smaller equipment footprint. The PowerReach system consists of JT at the bottom and CT on top to have the stiffness and weight of the JT at the bottom of the string and the freedom to move the CT portion on top without making connections. The length of CT depends on the length of the lateral or the distance from the first to the last section being treated. This ensures that the string can be moved freely without making a connection. Fig. 1 shows the setup of a hybrid unit on location, including a reel trailer, rig assist unit, and tower with tubing guide.

Extended reach open-hole sections in water injector wells present significant challenges for coiled tubing (CT) operations, especially during acid stimulation treatments where tool reach and precise fluid placement are critical. Excessive friction and drag often limit CT accessibility, resulting in incomplete stimulation and reduced injectivity. This case study highlights the successful deployment of a Hydraulic Activated Friction Reduction Tool (HOFRT) in two UAE water injector wells—Well B and Well C—to overcome these limitations and improve treatment effectiveness. Both wells had a history of unsuccessful CT interventions due to high frictional forces and limited reach. The recent operation involved three approaches: Conventional bottom hole assembly (BHA)Conventional BHA with acid spottingBHA with HOFRT deployment HOFRT was introduced to generate axial oscillations along the CT string, reducing contact with the wellbore and converting static friction into dynamic friction. This mechanism extended CT reach beyond previous lock-up points. Once improved accessibility was achieved, targeted acid stimulation was performed to treat the full open-hole interval. The use of HOFRT significantly reduced friction and extended CT reach beyond prior limits. In Well X, the intervention achieved 100% coverage of the open-hole section, with a 92% improvement in accessibility and an 80% increase in injectivity index (II). In Well Y, although CT reach improved by 117% compared to previous attempts, full coverage was not possible due to CT size constraints. Nevertheless, the injectivity index improved fivefold, demonstrating the tool's effectiveness even under limited access conditions. The operation confirmed that HOFRT could delay lock-up and prevent buckling, enabling smoother and deeper tool conveyance. This study demonstrates the practical value of HOFRT in extended reach wells where conventional CT BHAs fail to provide adequate access. By enabling deeper reach and more effective acid placement, HOFRT opens new possibilities for stimulation in complex well geometries. The lessons learned—particularly regarding CT sizing and tool activation timing—offer valuable guidance for future interventions in similarly challenging environments. This case study sets a precedent for adopting friction reduction technologies to enhance well performance and intervention success in extended reach applications.

This paper describes and analyzes the development and ongoing field trials of a Real Time MWD Coiled Tubing Drilling System. The new system holds great promise for advancingthe state of coiled tubing drilling for certain applications. The system is designed for through-tubing, short radius re-entry and drilling highly deviated wells as horizontal laterals to a geologic target with minimum wellbore tortuosity. Currently, 4- 1/2' production tubing is the smallest re-entry candidate. Real time MWD and Bottom Hole Assembly (BHA) control is achieved by the use of a combination hydraulic and electric umbilical internal to the coiled tubing (CT), allowing continuous data collection and selective surface control of the BHA components, This communication line allows orientation in 10' increments (or less) while drilling, applies weight-on-bit and operates a reusable circulating valve. In addition, the umbilical provides real-time monitoring of weight-on-bit, circulating pressures of the drilling fluid internal and external to the BHA, dedicated hydraulic system bottom hole pressure, downhole temperature and survey data from logging equipment. Introduction In. June of 1992, Cameo Products & Services formed a coiled tubing drilling team that consisted of engineering representives from Reed Tool Company, Hycalog. Cameo Coiled Tubing Services and Cameo Products & Services. The team's objective was to investigate the technical and economic viability of drilling with CT. Invitations were extended to experts and consultants with experience in slim-hole and CT drilling to address the team on existing and potential problems. The major technical difficulties identified were:CT bucklingpipe fatiguelack of real-time dataweigh t-on-bitreactive torquedependable emergency release from the BHAability to drill under balanced Key to solving these technical difficulties is the ability to provide hydraulic and electric power to the BHA via an umbilical installed in the CT, The umbilical allowed the development of hydraulically and electronically powered down hole tools and instrumentation that comprise the BHA. Purpose built surface equipment designed specifically for the BHA was developed to provide surface power and selective controls. After conceptual drawings of the BHA were completed, Cameo and BP Exploration (Alaska) began a development project for specific application at Prudhoe Bay, where CT drillingtechnology is considered to be a very valuable tool. Many of the existing wells at Prudhoe Bay could potentially benefit if replaced with horizontal completions. CT drilling offers the potential of achieving horizontal sidetracks without pulling the existing tubing. This offers a significant cost advantage over conventional sidetracks.

Successful reservoir surveillance and production monitoring is a key component for effectively managing any field production strategy. For production logging in openhole horizontal extended reach wells (ERWs), the challenges are formidable and extensive; logging these extreme lengths in a cased hole would be difficult enough, but are considerably exaggerated in the openhole condition. A coiled tubing (CT) logging run in open hole must also contend with increased frictional forces, high dogleg severity, a quicker onset of helical buckling and early lockup. The challenge to effectively log these ERWs is further complicated by constraints in the completion where electrical submersible pumps (ESPs) are installed including a 2.4" bypass section. Although hydraulically powered coiled tubing tractors already existed, a slim CT tractor with real-time logging capabilities was not available in the market. In partnership with a specialist CT tractor manufacturer, a slim logging CT tractor was designed and built to meet the exceptional demands to pull the CT to target depth. The tractor is 100% hydraulically powered, with no electrical power allowing for uninterrupted logging during tractoring. The tractor is powered by the differential pressure from the bore of the CT to the wellbore, and is operated by a pre-set pump rate from surface. Developed to improve the low coverage in open hole ERW logging jobs, the tractor underwent extensive factory testing before being deployed to the field. The tractor was rigged up on location with the production logging tool and ran in hole. Once the coil tubing locked up, the tractor was activated and pulled the coil to cover over 90% of the open hole section delivering a pulling force of up to 3,200 lb. Real-time production logging was conducted simultaneously with the tractor activated, flowing and shut-in passes were completed to successfully capture the zonal inflow profile. Real-time logging with the tractor is logistically efficient and allows instantaneous decision making to repeat passes for improved data quality. The new slim logging tractor is the world's slimmest most compact, and the first of its kind CT tractor that enables production logging operations in horizontal extended reach open hole wells. The ability to successfully log these extended reach wells cannot be understated, reservoir simulations and management decisions can only as good as the quality of data available. Some of the advantages of drilling extended reach wells such as increased reservoir contact, reduced footprint and less wells drilled will be lost if sufficient reservoir surveillance cannot be achieved. To maximize the benefits of ERWs, creative solutions and innovative designs must continually be developed to push the boundaries further.

Executing interventions in wells encrusted with wax is challenging because experience with global coiled tubing (CT) dewaxing operations is limited, and equipment failure and stuck pipe risks are high. With few jobs performed worldwide, CT dewaxing (hot oil circulation with CT) operations are largely unexplored. The deviated wells in a field in northeast India pose several challenges including completely seized wellbore due to paraffin/asphaltene deposition, previous failed well cleanout attempts, very slow and low bottomhole assembly (BHA) penetration, pumping corrosive and flammable low wax crude (LWC) through CT, high chances of CT getting stuck, and pumping heated 69°C LWC through the CT. This case study delivers insights about design, safety, and operational considerations for 1.5-in. CT dewaxing and nitrogen lift operations in a subhydrostatic well in the field. The objective of this CT dewaxing and nitrogen kickoff operation was to clear the well of paraffin/asphaltene/wax to 1600 m and activate it with nitrogen, and this paper describes solutions for cleaning out and nitrogen-lifting wells with declining production due to paraffin and asphaltene deposition. One well is described in this case study, but this approach can be used perform CT intervention in similar wells. For this case, simulations were sensitized to identify the best combination of pumping rates, CT speeds, and fluid temperature to remove deposits hindering BHA penetration. This study proposes prevention measures using appropriate grounding and procedures, which determine if the crude oil can be pumped through CT. By use of this methodology, 581 dewaxing runs have been performed in 78 wells. Extensive on-job experience and lessons learnt by performing this operation over the last 3 years bring excellent results and prevent misruns. In many cases, production has been restored from nil; several examples feature a fivefold improvement of productivity thanks to this intervention method. Optimized operational parameters such as CT speed, pumping rates, and the use of smaller outer diameter BHAs doubled operational efficiency during those operations. In addition, strict application of the recommendations prevented the occurrence of operational problems such as stuck CT, crude oil flashing, sand bridging, and equipment failure.

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 189910, “Operational Improvements Using a Coiled-Tubing-Telemetry System for a Complex Milling Operation in Shut-In Conditions,” by P. Correa, D. Parra, S. Craig, SPE, S. Livescu, SPE, A. Yeginbayev, and Z. Nadirov, Baker Hughes, a GE Company, prepared for the 2018 SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, The Woodlands, Texas, USA, 27–28 March. The paper has not been peer reviewed. When a new horizontal well in Asia was incapable of unassisted flow, coiled tubing (CT) was selected for the perforation and stimulation intervention. Mechanical isolation was required to ensure that the stimulation fluids entered only the new zones. Accurate depth control was required for three runs: setting two composite bridge plugs (CBPs), deploying CT-conveyed perforating guns for opening two intervals, and milling out the two CBPs without taking returns to surface. For the first time, a tension, compression, and torque (TCT) subassembly was used to improve the milling operation. Introduction CT telemetry (CTT) systems have proved to be effective in enhancing operations by providing real-time monitoring of downhole data including depth, pressure, temperature, force, and torque. For data transmission from downhole sensors to surface, these telemetry systems can use either insulated wire or optical fiber. With insulated wire, power can be transferred from surface to the downhole sensors. With optical fiber, downhole batteries are required in the bottomhole assemblies (BHAs) to power the downhole sensors. When compared with braided systems using the 0.125-in. insulated electrical cable (Fig. 1), the main advantages of the CTT system are its low weight and the fact that balls can be pumped through the CT. A small wire has a minimal effect on the CT cross-sectional area. Balls up to 7/8 in. in diameter do not become stuck, and there is a minimal effect on the CT fluid pressure drop. Description of the Wire CTT System The 0.125-in.-wire CTT system has several components, such as surface hardware and software; the ⅛-in. insulated electrical conductor inside the CT string; and a BHA with different sizes, including 2.125, 2.875, and 3.5 in. The 2.875-in. BHA with three subassemblies is shown in Fig. 2. The 2.875-in. sensor assembly has the following components: Tubing end connector Head that secures the wire downhole, seals the exterior of the wire, and provides downhole electrical connection 0.875-in. ball-operated wire-release mechanism Double-flapper check-valve housing Electronic module with a casing collar locator (CCL) and pressure/temperature sensors (internal/external) Motorhead section, where a ¾-in. ball-release mechanism is located followed by a circulating port activated with 0.625-in. balls Burst-disk section enabling 0.5-in. balls to pass through to activate downhole tools

Canada has played a prominent role in the development of horizontal drilling technology. To date, over 1,400 "grassroots" and "re-entry" wells have been drilled. Although other countries have experienced greater numbers of wells, the number of different types, varieties, and formations tested with this technology in Canada is unparalleled. Due in part to the exponential growth of horizontal well applications since the mid-1980's, coiled tubing CCT) technology in Canada has been adapted and evolved for more traditional uses such as horizontal well stimulation, evaluation, workovers, and clean-outs. The principal nontraditional aspect of CT is its use in drilling operations. This paper will deal with the current state and recent advances in CT horizontal drilling in Canada, A brief historical perspective will be presented that highlights Canada's presence as a pioneer in CT drilling and documents its evolution from vertical re-entries dating back to 1974, grassroots vertical wells in 1976, to the industry's current efforts at vertical and horizontal CTD. The principal Canadian service companies are reviewed in terms of present capabilities in CTO applications and the perceived driving forces that are stimulating the development of this emerging technology. The key factors such as diameter and fatigue life of the coil, length limitations, bottom hole assemblies, surveying methods and the economic and market factors affecting CTO relative to more conventional drilling techniques are reviewed. Finally, the future technological, market and economic developments necessary for the successful implementation of CTO for grassroots vertical and horizontal well re-entry projects are suggested. Introduction The exponential growth in the number of horizontal well applications in Canada and internationally over the past eight years has led to a relatively rapid development of both personnel and equipment to enhance the horizontal drilling method of exploiting existing oil and gas pools. In Canada, there are an estimated 70,000 producing wells: 40,000 gas wells and 30,000 oil wells. Recently, the National Energy Board (NEB) presented a study on horizontal oil wells and their impact on future crude oil supply in Canada. They estimated that there is a potential market of over 12,000 horizontal wells that can be economically drilled within 1,800 oil pools at a market price of $20 US/Bbl. Of these 12,000 wells, 5,000 were believed to be grassroots in nature (1 I 100 have been drilled to date) while 7,000 were horizontal re-entries through existing cased wells (300 have been drilled to date). Of the 6,700 remaining re-entries, the competition for services will be between slim hole (less than or equal to 6–1/4 in. hole size) conventional drilling systems using drilling rigs or modified service rigs and coiled tubing drilling (CTD) technology. Add to this potential market vertical deepenings, horizontal lengthenings and grassroots wells coupled with increasing interest in horizontal exploitation of gas pools, and the development of CTD appears to be poised for exponential growth in Canada over the next five years. Some of the questions that will be addressed during the course of this paper are:

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208988, “Novel Application of Abrasive Jet Perforating To Restore Productivity of a High-Potential Inactive Horizontal Oil Producer,” by Sadaf S. Chishti, SPE, Steven H. Craig, SPE, Baker Hughes, and Edward J. Wheatley, SPE, ADNOC, et al. The paper has not been peer reviewed. The complete paper illustrates a novel methodology that enabled the safe application of coiled tubing (CT) abrasive perforation to increase production in a sour horizontal extended-reach (ER) oil producer. The well was underperforming at 10% of the anticipated production rate because of a damaged lower completion. To avert a costly workover, abrasive perforation with CT was selected as a safe alternative to conventional explosives-based perforating conveyed on electric line. Introduction An offshore horizontal ER producer well was drilled with a total depth (TD) in excess of 24,000-ft measured depth (MD). During the completion phase, a 4.5-in. liner with 16 inflow control devices (ICDs) and eight swellable packers was run with the ICDs in the closed position. Swellable packers were placed after every two ICDs. To open these ICDs, an internal pressure of 2,500 psi was required, achieved by dropping a ball that would seat in the float collar. Multiple attempts were made to pressure up and open the ICDs without success. The decision was made to run the upper completion with a plan to activate the ICDs using rigless CT intervention. After a drift CT run, multiple attempts were made to run a through-tubing inflatable packer bottomhole assembly (BHA) on CT to isolate and pressure up the well. All attempts failed to reach target depth, with repeated holdup at approximately 20,273-ft MD. Production-logging passes performed in injection mode determined that the well interval between 20,262 and 20,300 ft was taking more than 80% of the injected fluid. In a subsequent CT logging run, a caliper log identified that the liner section in this interval was parted and identified an openhole section with washouts in excess of 7-in. inner diameter. The results from the log are shown in Fig. 1, with the enlarged section representing the parted liner/openhole interval. Because the ICDs remained closed along with a damaged liner section, the options of recovery leaned heavily toward a rig-based workover for sidetrack and recompletion. Considering time and cost constraints, studies commenced to identify an efficient alternative to establish flow contribution from the inactive compartments by adding perforations. CT was chosen as the conveyance method based on previous success in reaching TD, and three options were evaluated. Based on the lowest risk level and availability of resources, the safest and most-viable option was abrasive perforation with CT. This technique uses a sand jet perforator, a downhole tool that uses high-pressure abrasive-laden fluids to penetrate the casing, liner, and cement and extend a cavity into the reservoir.

Well intervention challenges present opportunities to develop new technologies that increase operation efficiency and effectiveness. A revolutionary real-time hybrid coiled tubing (CT) service marks a new era of informed interventions. This paper highlights the results from 3 years of field operations using this real-time hybrid CT technology to improve well interventions economically, logistically, operationally, and technically by performing analysis and making decisions in real time. Previous techniques used wireline units to perform real-time operations, which often required production shut-in and multiple runs to avoid operational issues (i.e., tool lifting in wells with high production rates). CT electric line units mitigate the shut-in requirement, but reduce the pipe pulling capabilities and limit the fluids and rates to be pumped through the pipe. CT with fiber-optics technology helps eliminate the shut-in requirement and the fluids and rates restrictions, without affecting the CT pulling capabilities. However, operating time is limited because of the power source life. During the 3-year period, more than 1 million running feet of CT well interventions were performed in the eastern foothills of Colombia, where challenging conditions, such as high gas production rate, high tortuosity, and dogleg severity, were overcome using the real-time hybrid CT service. The real-time hybrid CT service includes an open architecture system that provides the capability to pump any fluid type at different rates through the CT and hybrid downhole tool. Additionally, the system is compatible with all electric and mechanical tools using a plug-and-play adapter to attach tools in a single rig up, which helps eliminate additional rig up and rig down of units to perform other types of well interventions. A continuous power supply allows operations to be performed without time or power constraints. This paper reviews previous case histories in which multiple interventions were successfully performed in a single run using real-time hybrid CT technology, including zonal isolation, well surveillance, access recovery, stimulations, production logging, injection logging, completion visualization, and perforating under extreme underbalanced conditions with extremely long bottomhole assemblies (BHAs). The flexibility of the real-time hybrid CT technology provides multiple opportunities to address new challenges in the oil industry without limits.

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.

A laboratory and field study directed at improved well performance of horizontal wells is discussed. During the study, several wells were matrix acidized using bullhead and coiled tubing placement techniques. The study performed in carbonate reservoirs indicates acid placed with coiled tubing diverted with foam provides excellent zone coverage and damage removal. Conventional bullhead techniques do not result in effective damage removal. The study emphasizes the evaluation of the treatment results and the development of improved acidizing techniques. Laboratory simulations of matrix acidizing indicate proper placement techniques are essential. This observation is supported by field data in oil wells completed in carbonate reservoirs. The key to successful damage removal is 1) the placement of acid via coiled tubing and 2) proper diversion. Production logging and well performance data support this claim. The proposed treatment is applicable in both horizontal and vertical wells completed in carbonate reservoirs.

Horizontal well completions are often equipped with Inflow Control Devices (ICDs) to optimize flow rates across the completion for the whole length of the interval and to increase the oil recovery. The ICD technology has become useful method of optimizing production from horizontal wells in a wide range of applications. It has proved to be beneficial in horizontal water injectors and steam assisted gravity drainage wells. Traditionally the challenges related to early gas or water breakthrough were dealt with complex and costly workover/intervention operations. ICD manipulation used to be done with down-hole tractor conveyed using an electric line (e-line) cable or by utilization of a conventional coiled tubing (CT) string. Wellbore profile, high doglegs, tubular ID, drag and buoyancy forces added limitations to the e-line interventions even with the use of tractor. Utilization of conventional CT string supplement the uncertainties during shifting operations by not having the assurance of accurate depth and forces applied downhole. A field in Saudi Arabia is completed with open-hole packer with ICD completion system. The excessive production from the wells resulted in increase of water cut, hence ICD's shifting was required. As operations become more complex due to fact that there was no mean to assure that ICD is shifted as needed, it was imperative to find ways to maximize both assurance and quality performance. In this particular case, several ICD manipulating jobs were conducted in the horizontal wells. A 2-7/8-in intelligent coiled tubing (ICT) system was used to optimize the well intervention performance by providing downhole real-time feedback. The indication for the correct ICD shifting was confirmed by Casing Collar Locator (CCL) and Tension & Compression signatures. This paper will present the ICT system consists of a customized bottom-hole assembly (BHA) that transmits Tension, compression, differential pressure, temperature and casing collar locator data instantaneously to the surface via a nonintrusive tube wire installed inside the coiled tubing. The main advantages of the ICT system in this operation were: monitoring the downhole force on the shifting tool while performing ICD manipulation, differential pressure, and accurately determining depth from the casing collar locator. Based on the known estimated optimum working ranges for ICD shifting and having access to real-time downhole data, the operator could decide that required force was transmitted to BHA. This bring about saving job time while finding sleeves, efficient open and close of ICD via applying required Weight on Bit (WOB) and even providing a mean to identify ICD that had debris accumulation. The experience acquired using this method in the successful operation in Saudi Arabia yielded recommendations for future similar operations.

Matrix acid stimulation throughout a well’s life cycle is a common technique applied to wells with impaired productivity. Coiled tubing is often chosen as the conveyance means for delivering the acid treatment in horizontal wells to the damaged zones and in applying effective chemical divergent for highly permeable zones. Due to the nature of helical buckling, weight stacking, and wellbore geometry, the coiled tubing operation is often limited in its ability to reach total depth (TD).In short horizontal wells with slight reservoir contact, conventional methods are used to overcome the effect of drag and friction on the CT; such methods include pumping lubricant fluid. In more challenging applications and extended reach wells (ERW’s), a downhole pulsation tool is placed in the bottomhole assembly to add some axial vibration to the string and exert a pulling force to delay the onset of CT helical buckling, which, in turn, increases the reach of the coil. The significant reduction in friction is caused by the Flow Activated Pulsation Tool (FAPT), which allows the CT to increase its coverage and reach the desired target depth.A new FAPT generation was developed by designing a new valve section to meet the objective of extending the CT reach in highly restricted (2.44") ERW’s. The development of the new valve section was completed after series of testing different valve sections to determine the optimum generated pulses that would increase the overall pull force at the lowest activation flow rate. The newly developed tool offers a stronger and higher performing pulses at lower activation flow rate, allowing it to operate effectively in more challenging ERW’s.The FAPT development and the results of using the new tool after the first two global trial runs. The two wells were drilled as oil producing horizontal wells with +18,000 feet to TD. The wells were completed as open hole with electric submersible pumps (ESP’s) and a 2.44’’ restriction to allow well intervention. In both runs, the goal was achieved by reaching TD of the openhole section with effective placement of the acid treatments.