Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Cairn Energy India Private Limited (CEIL) started development in Mangala field with aggressive target of drilling 60-70 wells/year (7days/well). Therefore, the focus was to reach high drilling efficiency which will ultimately reduce the well cost. Some of the challenges faced were placing wells in greatly faulted zones, high uncertainty in shallow TVD reservoir, requirement of tangent for installation of ESP, smooth hole to avoid problem running screen and collision risk due to closely spaced wells. RSS was generally used only in complex, high-cost offshore projects where the savings realized were significant. The industry has been slower to adopt the use of RSS for onshore directional drilling applications however CEIL took a step ahead by deploying RSS for Mangala field development. RSS was utilized in directional wells to optimize drilling performance and deliver smoother hole profile. Advanced LWD services such as bed boundary detection tool along with RSS have brought value in successful landing and placement of horizontal wells in the best reservoir strata. Application of near-bit gamma ray and other LWD measurements to identify the top of reservoir as early as possible has helped to avoid the requirement of drilling pilot holes. This paper discusses such application in detail and presents its benefits.The result was a noticeable improvement in well delivery time, reduced drilling cost, and improved hole quality. This paper compares the drilling performances with PDM vs RSS in the same field and presents the lessons learnt in the process of field development. RSS delivered less tortuous hole which result in a problem-free liner or screen run. Hole cleaning was improved which allowed to drill at faster ROP without taking risk of well complication. Time versus Depth analysis clearly indicated that RSS was both technically and economically, a sound approach for drilling the wells in Mangala field. This paper showcases a case study where RSS application proven to be cost-effective solution even in low-margin onshore field development. Mangala Field OverviewThe Mangala Field is located in the northern Barmer Basin of Rajasthan state, India. The basin is a Tertiary rift, predominantly consisting of Palaeocene-Eocene sediments. The Mangala Field was discovered in January 2004 with Mangala-1 then appraised by drilling of 6 more wells, including acquisition of a 3D seismic survey, and major data gathering efforts involving core, fluids, and well testing 1 .The main reservoir unit in the Mangala Field is the Fatehgarh Group, consisting of interbedded sands and shales. The group has been sub-divided into the Lower Fatehgarh Formation dominated by well-connected sheetflood and braided channel sands, and the Upper Fatehgarh Formation dominated by sinuous, meandering, fluvial channel sands. Five reservoir units are recognized in the Mangala Field, named FM1-FM5 from the top downwards. FM1 and FM2 comprise the Upper Fatehgarh Formation and FM3, FM4 and FM5 form the Lower Fatehgarh Formation. The overlying Barmer Hill Form...
Cairn Energy India Private Limited (CEIL) started development in Mangala field with aggressive target of drilling 60-70 wells/year (7days/well). Therefore, the focus was to reach high drilling efficiency which will ultimately reduce the well cost. Some of the challenges faced were placing wells in greatly faulted zones, high uncertainty in shallow TVD reservoir, requirement of tangent for installation of ESP, smooth hole to avoid problem running screen and collision risk due to closely spaced wells. RSS was generally used only in complex, high-cost offshore projects where the savings realized were significant. The industry has been slower to adopt the use of RSS for onshore directional drilling applications however CEIL took a step ahead by deploying RSS for Mangala field development. RSS was utilized in directional wells to optimize drilling performance and deliver smoother hole profile. Advanced LWD services such as bed boundary detection tool along with RSS have brought value in successful landing and placement of horizontal wells in the best reservoir strata. Application of near-bit gamma ray and other LWD measurements to identify the top of reservoir as early as possible has helped to avoid the requirement of drilling pilot holes. This paper discusses such application in detail and presents its benefits.The result was a noticeable improvement in well delivery time, reduced drilling cost, and improved hole quality. This paper compares the drilling performances with PDM vs RSS in the same field and presents the lessons learnt in the process of field development. RSS delivered less tortuous hole which result in a problem-free liner or screen run. Hole cleaning was improved which allowed to drill at faster ROP without taking risk of well complication. Time versus Depth analysis clearly indicated that RSS was both technically and economically, a sound approach for drilling the wells in Mangala field. This paper showcases a case study where RSS application proven to be cost-effective solution even in low-margin onshore field development. Mangala Field OverviewThe Mangala Field is located in the northern Barmer Basin of Rajasthan state, India. The basin is a Tertiary rift, predominantly consisting of Palaeocene-Eocene sediments. The Mangala Field was discovered in January 2004 with Mangala-1 then appraised by drilling of 6 more wells, including acquisition of a 3D seismic survey, and major data gathering efforts involving core, fluids, and well testing 1 .The main reservoir unit in the Mangala Field is the Fatehgarh Group, consisting of interbedded sands and shales. The group has been sub-divided into the Lower Fatehgarh Formation dominated by well-connected sheetflood and braided channel sands, and the Upper Fatehgarh Formation dominated by sinuous, meandering, fluvial channel sands. Five reservoir units are recognized in the Mangala Field, named FM1-FM5 from the top downwards. FM1 and FM2 comprise the Upper Fatehgarh Formation and FM3, FM4 and FM5 form the Lower Fatehgarh Formation. The overlying Barmer Hill Form...
Summary When kicking off at low inclination, static measurement-while-drilling (MWD) surveys are used to confirm the kickoff direction, when free of magnetic interference from offset wells. However, because MWD continuous azimuth and inclination measurements have limited accuracy when near vertical, the directional driller does not have confidence in the kickoff direction with continuous (dynamic) survey while drilling. This requires additional static surveys to be made, taking up rig time. In a novel continuous survey method used in a particular rotary-steerable system (RSS), a six-axis survey was taken continuously, both while drilling and when static, with the survey sensors being housed in a rotation-speed-controlled platform in the RSS. This algorithm was first verified in a software simulator, and it was subsequently implemented in hardware and tested in a hardware-in-the-loop (HIL)-simulator environment. The effectiveness of the new measurement method was field tested and compared with MWD static survey points. The field-test result shows that the new near-bit continuous azimuth and inclination measurement from the RSS is considerably more accurate than the MWD continuous measurements at very low inclinations less than 5°. The new survey method not only provided more-accurate kickoff from a near-vertical position but also enhanced the automated-vertical-drilling feature. In addition, improved continuous measurements around magnetic north and south allowed the closed-loop attitude-hold algorithm of the RSS to drill lateral sections more precisely in these directions. This unique measurement method has valuable applications, such as low-angle kickoff without the use of multiple static surveys because the directional driller can use the continuous azimuth and/or tool face to accurately steer the well. Equally important is that if gyro surveys are required, their number will reduce when the survey-measurement point is so close to the bit, reducing the amount of time of exposure to magnetic interference from an offset casing. When drilling out of the shoe, this survey method will allow an accurate kickoff approximately 50 ft earlier than would normally be expected when magnetic interference is cleared. In addition, the use of a continuous gravity tool face (GTF) is possible without the need for static surveys, allowing accurate low-side sidetracks to be performed even in areas of high magnetic interference. This surveying method reduces the rig time needed to kick off and provides a more reliable real-time measurement for the directional driller to ensure that the desired well trajectory is drilled through crowded platform environments.
The first commercial high-dogleg rotary-steerable systems (RSSs) were introduced in 2011. These systems were specially designed to drill vertical, kick off, build at planned 8 to 12°/100 ft (or even higher), and drill the lateral to lengths of up to 6,000 ft in unconventional reservoirs (such as shale gas applications) in North America. Because of the improved economics and other benefits for efficient drilling a high-build-rate curve and lateral in single run, high-dogleg RSS technology has rapidly gained acceptance for drilling shale wells.The performance of the high-dogleg RSS is greatly enhanced with automated steering mode in vertical and lateral sections by reducing a human-machine interaction and minimizing wellbore tortuosity in these sections. Downhole trajectory-control algorithms make small, but frequent, adjustments to RSS steering parameters, comparing the near-bit continuous survey data against a planned well trajectory. Downhole steering automation is an integral part of the overall drilling system automation that the drilling industry is pushing forward.A new static and continuous (dynamic) survey method has been used in the near-bit sensors of a specific high-dogleg-severity (DLS) RSS. The new survey method significantly improved the inclination and azimuth measurement in near-vertical angles; thus, it not only enhanced the automated vertical drilling feature but also provided more accurate kickoff from a near-vertical position using the RSS near-bit static and continuous survey. In addition, improved continuous measurements around magnetic north and south allowed the closed-loop trajectory-following algorithm of the RSS to drill lateral sections more precisely in these directions.The software simulation and field trials were conducted to test a new survey measurement method implemented in a highdogleg RSS, along with automatic trajectory-following algorithms. In one of the field trials, the RSS drilled more than 10,750 ft (vertical, high-dogleg curve, and lateral) in one run, including 5,000 ft of vertical and 4,500 ft of lateral sections in automated steering mode, saving 4 days (about 30%) compared with the previous non-high-dogleg RSS runs. A unique combination of the new technologies has enabled increased well construction efficiency in shale plays by providing a step change in steering technology, trajectory-following algorithms, and downhole survey method.
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.
customersupport@researchsolutions.com
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.