Recent drilling activities in the State of Kuwait have focused on the search for high quality oil from the Jurassic formations. The wells drilled to these prospects are very challenging because of HPHT conditions, presence of high levels H 2 S and CO 2 , and narrow pore/fracture pressure windows.The targeted Jurassic formations are the Najmah-Sargelu and Middle Marrat, which are located below the Gotnia salt/anhydrite. These reservoirs consist of layered shales and limestones, which can be highly fractured. One of the main challenges in the effective development of these reservoirs is the ability of the wells to access a permeable interconnected vertical fracture network. Horizontal well profiles increase the probability of crossing multiple fractures or fracture swams, resulting in high productivity and reserve recovery per well.A 'Conceptual Project' was set up with the objective to design the first horizontal well to be drilled through the Najmah reservoir, in the North Kuwait fields. The challenges included; the establishment of an optimum well trajectory, drilling through the mobile salt section of the Gotnia at well inclinations above 60º, planning a pilot hole in the reservoir section to facilitate positioning of the lateral, identifying suitable water base mud system to improve image log quality, planning a high DLS openhole sidetrack just below 10 3/4" casing shoe and introducing a casing string (just above lateral) to address borehole stability concerns.To address these challenges a team based approach was established between operator and contractors, to develop the well design, detailed engineering and operational procedures. This paper will describe the methodology adopted during this well design process and the technical challenges faced and overcome.
An operators renewed focus on horizontal well drilling and open hole completions, using Inflow Control Device (ICD) screens, necessitated the use of oil-based drill-in fluids (DIF) to drill and complete their reservoir. The challenges were increased by low reservoir pressure conditions, increasing the risk of drilling fluid invasion and possible reservoir damage. Comprehensive laboratory studies were carried out to evaluate DIF performance and ensure understanding of the possible damage mechanisms produced while drilling, considering the reservoir characteristics and drilling conditions.The customized near-wellbore damage remediation system, with a delay-reaction, was designed based on Mesophase technology. This paper discusses detailed laboratory analysis for the clean-up system and its field applications in Kuwait horizontal wells. The applications included drilling carbonate and sandstone reservoirs, open hole ICD completion, and performing effective cleanup required for maximum production.The effectiveness of the Mesophase clean-up system to remediate reservoir damage and improve producibility was evaluated immediately after well kick off and again after steady production levels were reached. This paper shows the results obtained after the application of the near-wellbore remediation technology.The lessons learnt during the Mesophase application were incorporated on upcoming wells to standardize the operating procedures and improve field performance.
Exploration activities in Kuwait involve drilling of HPHT wells to search for high quality oil from the Jurassic formations. The wells drilled are very challenging with deep horizons (~16,500 ft), over-pressured formations and zones with narrow pore/fracture pressure windows which require the setting of multiple casing strings.It is imperative that surface/intermediate casing strings are run to the maximum depths possible in order to reach well TD in a workable hole size. This presents the challenge of drilling long sections of large diameter hole in an acceptable time frame while maintaining borehole quality such that the big diameter tubular strings can be successfully run. This paper will discuss the challenges of drilling 22" hole in such wells from 6,000 to 9,500 ft and the potential to replace established methods with new technology solutions to improve drilling performance.The conceptual project consisted of an attempt to replace multiple 22" insert bits, rotary driven, with a single PDC bit design run on downhole motor. A partnership approach was initiated with the bit manufacturer and motor provider. Bit designs, downhole motor and rig equipment specs were developed and improved on over the project.Bit and motor combinations were tested over a number of wells using several drilling rigs. The performance improvements were benchmarked with the original method. Over the trial, the goal was to try and drill the entire section with one bit from shoe to shoe, thus cutting interval costs and drilling times. This paper will detail key factors in drill bit design, analysis of downhole motor performance, plus the critical role of 'state of the art' rig equipment. It will present a case history of this 'design and development' process with conclusions which provide the basis for future optimization of the technology.
Enhance Production by 100,000 bbls/day; Optimize and sustain Production rate by reduction in Water-cut; Drill over 100 Horizontal and Sub-Horizontal wells to increase production by over 1000 bbls/day/well and Smart completion methods to delay water-cut and maximize oil recovery. These objectives sounds straight out of the Management dream Wish-list to impress the stake-holders. Well, not so for Kuwait Oil Company. These were indeed the objectives of recovering an aging field and creating a complete make-over of the fortune from this oil field in North of Kuwait. And as expected from all such grandiose projects, it did run into its own share of road blocks in achieving these objectives. Uncertain geological data, troublesome shale's cut at high angles, improper hole-cleaning practices, crew un-accustomed to handling challenges of horizontal wells and found wanting in many technical aspects, aging rigs finding it difficult to keep up to the demands of good hole cleaning and solids control, various short-coming of directional vendors and tools, completing wells with stiff ICD assemblies were the challenges which made the project stand the test of time and money. KOC stood up to these challenges and devised strategies, practices and methods to overcome these crippling challenges. Wells which initially were completed in over 120 days were brought down through innovative solutions, state-of-art technology, sheer will-power and determination to succeed down to 45 days on an average. This paper is going to highlight optimizations, innovations and usage of cutting edge technology carried out to overcome these stiff challenges. The learning curve was steep but it was overcome with sharing of knowhow through team-work and the burning zeal to succeed. This success story definitely holds lessons for all those who embark on the road to create magic. And this story definitely needs to be told over and over again.
Drilling activities have increased in the State of Kuwait to enable the production of more gas from the Jurassic formations. The wells drilled to these prospects are challenging because of HPHT conditions, sour reservoir fluids and narrow drilling window. Only vertical and deviated wells have been drilled to date, and in order to augment the production requirements horizontal wells were planned. For effective development of these reservoirs, horizontal well profiles were planned to increase the ability of the wells to access a permeable interconnected vertical fracture network which could result in high productivity and reserve recovery. After detailed study, well SA-297 was selected as an appropriate candidate for a horizontal pilot project. In this pilot, the objective was to drill the first horizontal well through the Najmah reservoir in the North Kuwait fields. The project, being the first of its kind, posed many challenges. These included: drilling and casing 16" hole at 60° well trajectory to 13,500 ft.; drilling the salt-anhydrite high pressure Gotnia at 60° inclination; drilling a slim pilot hole in the reservoir with K-formate WBM to facilitate positioning of the lateral; plug back this pilot hole and execution of a high DLS sidetrack just below 10 3/4" shoe; casing off formations with borehole stability concerns; drilling 6" lateral hole by geo-steering; tubing plugging concerns during DST testing. Due to plugging of the tubing during testing, an intervention job was carried out with a workover rig to clear the tubing with coiled tubing in a live well and subsequently retrieve DST tools. This was a unique job carried out for the first time in Kuwait. This paper will give details on the well construction, the complexities in the drilling operations and technical challenges faced while drilling the directional trajectory and in the special workover operations.
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.