Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
The success of stimulation fluid placement in openhole extended reach wells (ERWs) through coiled tubing (CT) is highly dependent on the depth achieved. Friction forces and helical buckling typically cause early CT lockup, which limits the reach. Organic deposits in the wellbore increases frictional forces causing premature lockup or in some cases even complete blockage. Efficient removal of organic deposits enables CT to reach maximum depth to perform the matrix stimulation. Analysis of these organic deposits was conducted and following a thorough comparative test, a new solvent-external phase emulsion inhibitor was selected to treat the wellbore prior to matrix stimulation. Optimum cleanout methodology was identified for the CT run with a high-pressure jetting nozzle (HPJN) combined with a chemical dissolution effect of the chosen solvent. Focused, high-energy fluid streams loosen any compacted deposits, while the high rate of fluid passing through the tool allows for an efficient cleanout. A matrix stimulation treatment with CT was then executed in the openhole section of the ERW with a TD of 18,773-ft (9800-ft horizontal lateral section) with HCl and emulsified acid systems. By using a solvent-external phase emulsion, only the external phase of the emulsion containing the dissolver is in contact with organic deposits; the remaining internal phase fluid is not. This therefore allows a reduction in total solvent volume. The proposed wellbore cleanout treatment with HPJN reduced the friction coefficient between CT and the completion by 10%. In turn, it was verified that during the operation, an additional 3,320 ft of reach was achieved in the openhole section. Combined with other extended-reach techniques (i.e., mechanical agitator tools, friction reducers), it allowed the 2.0-in CT pipe to reach the TD of the well (18,773 ft). These efforts together maximized the reservoir contact during the matrix stimulation in the openhole section with HCl and emulsified acid systems. Distributed temperature sensing (DTS) methodology was used with the aid of fiber optic installed CT, and the intake profile of the openhole section was mapped. Analysis of the data was applied to optimize the pumping schedule to obtain uniform production contribution across the openhole section. The systematic engineering workflow presented includes the organic deposit diagnostic procedure, laboratory testing, chemical selection, and treatment application. This yields a wellbore treatment that minimizes friction for the remainder of the operation and enables maximum CT reach. This provides more insights of integrated matrix stimulation treatment with CT to overcome the serious challenges present in extended reach openhole wells.
The success of stimulation fluid placement in openhole extended reach wells (ERWs) through coiled tubing (CT) is highly dependent on the depth achieved. Friction forces and helical buckling typically cause early CT lockup, which limits the reach. Organic deposits in the wellbore increases frictional forces causing premature lockup or in some cases even complete blockage. Efficient removal of organic deposits enables CT to reach maximum depth to perform the matrix stimulation. Analysis of these organic deposits was conducted and following a thorough comparative test, a new solvent-external phase emulsion inhibitor was selected to treat the wellbore prior to matrix stimulation. Optimum cleanout methodology was identified for the CT run with a high-pressure jetting nozzle (HPJN) combined with a chemical dissolution effect of the chosen solvent. Focused, high-energy fluid streams loosen any compacted deposits, while the high rate of fluid passing through the tool allows for an efficient cleanout. A matrix stimulation treatment with CT was then executed in the openhole section of the ERW with a TD of 18,773-ft (9800-ft horizontal lateral section) with HCl and emulsified acid systems. By using a solvent-external phase emulsion, only the external phase of the emulsion containing the dissolver is in contact with organic deposits; the remaining internal phase fluid is not. This therefore allows a reduction in total solvent volume. The proposed wellbore cleanout treatment with HPJN reduced the friction coefficient between CT and the completion by 10%. In turn, it was verified that during the operation, an additional 3,320 ft of reach was achieved in the openhole section. Combined with other extended-reach techniques (i.e., mechanical agitator tools, friction reducers), it allowed the 2.0-in CT pipe to reach the TD of the well (18,773 ft). These efforts together maximized the reservoir contact during the matrix stimulation in the openhole section with HCl and emulsified acid systems. Distributed temperature sensing (DTS) methodology was used with the aid of fiber optic installed CT, and the intake profile of the openhole section was mapped. Analysis of the data was applied to optimize the pumping schedule to obtain uniform production contribution across the openhole section. The systematic engineering workflow presented includes the organic deposit diagnostic procedure, laboratory testing, chemical selection, and treatment application. This yields a wellbore treatment that minimizes friction for the remainder of the operation and enables maximum CT reach. This provides more insights of integrated matrix stimulation treatment with CT to overcome the serious challenges present in extended reach openhole wells.
The advantages of drilling extended reach wells (ERW’s) are well known; increased reservoir contact, reduced surface footprint and less wells drilled. Although the benefits of drilling these wells is clear, it is also essential to have the ability to conduct well intervention throughout the life of the well. Matrix acid stimulation and production logging are critically important well intervention operations for efficient reservoir management. Coiled tubing (CT) is commonly deployed in ERW’s to perform these intervention operations. For open hole ERW’s, the success of the operation is often directly correlated to the length of the lateral covered. For ERW’s that can exceed 30,000 ft, the challenges to reach total depth (TD) can almost be insurmountable in terms of overcoming the high frictional forces acting against the CT. The level of difficulty is further magnified covering open sections often greater than 10,000 ft, where additional frictional forces are present from the rock, high dogleg severity and well trajectory. High bottom hole temperature along with high H2S & CO2 levels pose further challenges. Formation damage after drilling may result in serious production and therefore economic consequences and it is imperative to restore reservoir permeability along the complete interval with accurate treatment placement. The same challenges are present for logging operations where the main objective is to determine the flow profile along the entire open hole section. To achieve the main objectives, a comprehensive approach is taken for these well intervention operations. Custom designed technologies have been developed to increase the open hole coverage achieved to provide good zonal coverage in matrix acid treatments and also a clearer understanding of multiphase flow from the formation during production logging. Technologies developed specifically to tackle these challenges are hydraulically powered CT tractors that can deliver up to 14,000 lbs pulling force and mechanical agitator tools that effectively reduce the total friction coefficient. Other technologies employed are a downhole compression/tension sub to monitor downhole performance in real time to enhance operational decision making. To extend the ultimate reach, certain techniques can add a few thousand feet in coverage. These techniques include high pressure jetting to clean out the horizontal section of the cased hole to lower the friction, strategically deploying friction reducer and using momentum assiduously. These new technologies and applied techniques opens the window to ultimately meeting the goals of improved well surveillance and treatment in long horizontal laterals. Creative solutions have been core to inventing the best fit for purpose technologies, with great leaps having been made through pioneering technologies to extend CT reach in these extreme conditions.
Maximizing well productivity in extended reach wells with open hole completions in Saudi Arabia has been hampered by the difficulty encountered by coiled tubing (CT) to fully access open hole laterals with sections surpassing 6-in bore diameter and 10,000-ft in length. This paper discusses the innovative technologies, engineering string designs, and procedures that have been developed to increase the capabilities, dependability, and predictability of CT interventions in such wells. An exhaustive CT tubing force modeling analysis compared the performance of designs in 2.375-in and 2.875-in diameters and identified key operating parameters for future models and reach contribution from tractors and vibratory downhole tools. Records were reviewed and compiled for the most recent wells designs with varying bore sizes, target depths, open hole sections, and operating parameters. These open hole horizontal wells generated high frictional drag forces due to large completion diameters and tortuous wellbore trajectory. The presence of СО2 and H2S limited usable CT to sour service grades. Comprehensive tubing force and hydraulic pre-job analyses were used as basis of iteration for the versatile 2.375-in, and 2.875-in CT designs with up to 32,000-ft length and +90 MT in weight, combining engineered designs with novel CT heat treatment technologies. These CT designs were developed for a wide range of well configurations, conditions, and intervention treatments. The string designs feature wall thickness configurations selected to maximize reach and life in sour environments. The engineered CT strings were able to reach target depth (TD), comparable to the predicted results of the pre-job analyses. The engineered CT strings provided complete stimulation treatment over entire target zones, while minimizing risk and maximizing production economics for the operator. Extensive pre and post job analyses demonstrate the new designs’ capability of reaching all target depths, with allowances made for reach-assisting technologies in long, tortuous wells. The agitators, high expansion tractors, lubricants, high-pressure jetting tools, and the combined or isolated use-case of each to reach TD, are discussed in this document, as they were critical to maximizing the overall success of the intervention. This paper outlines the strategies used to reach deep well TDs through CT string design for various open hole completions longer than 10,000-ft. Operational and logistical procedures were changed for these unprecedented CT strings —including mobilizing the largest commercially available CT units and injector equipment in terms of capacity and power. The most recent CT manufacturing technologies that have helped cement and broaden the limits of extended reach stimulation interventions in open hole wells will be documented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.