Kuwait Oil Company (KOC) has recently drilled the first multilateral well in a North Kuwait field to improve oil production in productive layers subjected to water coning problems by increasing reservoir exposure using Level 4 multilateral technology. The multilateral well targeted the same sand in different directions with two laterals. Both of the laterals were drilled using rotary steerable drilling systems to reduce drilling time. The drilling process used a full suite of logging while drilling (LWD) tools, including azimuthal deep resistivity technologies, to ensure the well path is precisely geosteered within the reservoir boundaries and density/porosity tools in real-time, combined with specialized modeling software to position the well in the best possible reservoir.Level 4 multilateral technology was selected after performing an extensive geological assessment and studying the challenges of exploiting oil in the target sand reservoir. The 12 1/4-in. main section was cased and cemented with 9 5/8-in. casing to the landing point; the 8 1/2-in. lateral-I was drilled and completed with 5 1/2-in. inflow control devices (ICDs). The sidetrack was performed by cutting a window from a specialized latch coupling in the 9 5/8-in. casing; the 8 1/2-in. section was drilled to the landing point, and the 7-in. liner was run and fully cemented. The 6 1/8-in. lateral-II was drilled and completed with 4 1/2-in. ICDs.The fully cemented and cased junction or bifurcation should help achieve greater well integrity and prevent fluid migration from the adjacent area, while the specialized latch coupling should help ensure easy access to either of the laterals, as required. The ICD technology and swellable packers were selected to delay water breakthrough from an active aquifer.This publication describes the application of multilateral and geosteering technologies, and analyzes the advantages and disadvantages of the first multilateral well drilled in North Kuwait that began with a campaign of higher order (Level 4) multilateral. The well is considered to be a pilot well to identify the feasibility of using multilateral technology as a production model to help enhance oil recovery and reduce drilling costs in the field by replacing the cost of drilling new wells.
Sidetracking a preexisting drilled and cased wellbore poses numerous challenges. When sidetracking in an openhole environment, additional verifications of hole conditions are needed, which contribute additional unique challenges. In this type of wellbore, the operators must plan by selecting the sidetracking depth and then ensure that all the objectives are met from a well authorization for expenditure standpoint and geological target perspective. The quality of the openhole window or rathole is of immense concern to operators because this quality ensures that the bottomhole assemblies (BHAs) will pass through the rathole without difficulty. The openhole gauge must be confirmed because it can pose additional risks that might lead to costly multiple trips into the well to ensure that the rathole is in good condition. This paper presents a unique case study in which the operator, Kuwait Oil Company (KOC), was faced with the possibility of geological losses at the kickoff in the wellbore while attempting to sidetrack an existing wellbore. The operator contacted an oilfield services company and requested a unique technical solution to precisely sidetrack the wellbore in the difficult formation containing fractured dolomites, which are known to cause severe to complete losses. While drilling the 12.25-in. section, the BHA became stuck in the fractured dolomitic limestone formation. In this section, the operator had previously experienced severe to complete losses. Because fishing attempts to free the stuck BHA were not successful, the operator decided to sidetrack the wellbore in the open hole using an openhole whipstock. A casedhole sidetrack option was ruled out because reactive swelling shales with producing sands were located above the sidetrack depth; therefore, combining these zones was not practical because of the low-mud-weight limit required for drilling the fractured dolomite below the target depth. In addition, because only 70 ft of open hole existed between the 13.375-in. casing shoe and the stuck BHA in the hole, sidetracking with a cement plug was nearly impossible. The openhole wellbore was logged with a caliper to confirm the wellbore gauge. Prejob planning consisted of understanding the compressive rock strength from the offset wells to identify the lithological challenges unique to this application. A hazard analysis risk-control method was adopted to identify the risks and apply appropriate mitigation measures. An operating parameters plan was formulated by the engineering team and discussed with the operator and service company personnel and followed throughout the job. The wellbore was successfully sidetracked in the 12.25-in. section in a single run using an openhole whipstock, avoiding the loss zone, and resulting in additional cost savings to the operator. The condition of the sidetracked rathole enabled smooth passage of the directional BHA to meet the directional objectives. Furthermore, the openhole whipstock operation eliminated the need for multiple cement plugs in the sidetrack (in view of severe loss zones below) as well as the time required for drilling with a dedicated motor BHA for openhole sidetracking operation, saving the operator a minimum of 6 days of rig time. This operation was the first successful 12.25-in. openhole sidetrack operation in the Middle East, Asia-Pacific, and sub-Sahara Africa regions. As a result of this successful operation, the operator is proactively recommending the new solution across the entire KOC organization for wells with similar scenarios. By applying this unique and reliable openhole whipstock technical solution, the drilling team was able to deliver a successful well based on the original casing plan without any need for further sidetracks or changes to the wellbore casing design.
Almost all worldwide oilfields which have been producing for a long time have reached brown level of maturity. Given the foreseeable increase in global oil demand and consumption in the near future, operators need to be innovative in finding new resources and developing plans to meet the production demand. Oilfield service companies have parallely kept the pace by continuously improving their technologies and evolving their product offering to support activities from exploration to production phases. Sabriyah Lower Burgan reservoir in North Kuwait has been producing for a long time after its discovery. Since oil production is mostly from massive and coal sand members for long time, exploitation of new reservoir is needed to sustain the field productivity. The non-traditional siderite layer (SID3) had been identified by Kuwait Oil Company (KOC) as a potential source of incremental oil production. The reservoir has a lower productivity index and cannot flow significantly in vertical wells. SID3 has a relatively thin layer (5-20 ft TVD) with high lateral variations and presence of regional coal, making it highly challenging for drilling operations. There were many cases of wellbore instability while drilling wells in Lower Burgan in the past. Geological uncertainty generated by pinch out sand bodies in the reservoir section, led to scratching unstable shales and coal layers prone to collapse, thus resulting in stuck pipe events due to hole pack-off. Large volume and size of cavings, restricted circulation, high over pull, tight spots while tripping, and severe time-dependent wellbore instability due to shale sloughing contributed to the event and resulted in costly sidetracks. The geomechanics study is a key technology in the oilfield industry to prevent wellbore instability, via optimization of well trajectory and proper mud weight selection. Application of the study outputs helps minimize drilling risk, diminish non-productive time and ensure well completion within the expected deadline. Horizontal well design is deemed as the most effective way to exploit the SID3 layer, and the application of High Definition Distance-To-Boundary (DTB HD) technology can help the operator mitigate geological uncertainties, maximize reservoir contact and hence boost production rate. Integration of proactive Distance-To-Boundary technology, geomechanics study and meticulous pre-drill preparation have led to the successful completion of several horizontal wells in the SID3 layer. As a result, the operator gained a significant increase in oil production compared to the vertical wells. The well production also benefited from advanced completions technology with inflow control devices, handling other production related matters like presence of shale/silty layers for optimum hydrocarbon recovery. This proves that high-end technologies, coupled with multi discipline domain expertise and high-performance teamwork, is key to sustain the industry's ability to respond to the increase in global energy demand.
PDC bit designs for directional drilling typically sacrifice penetration rate for steering performance, resulting in a higher cost per foot. This paper discusses a process for modeling the drilling behavior of PDC bits, insights gained regarding bit efficiency when steering with various motorized and non-motorized rotary steerable systems (RSS), and field experience with the resulting bit design. Prediction and analyses of PDC bit behavior used a bridgeable software platform to integrate various design applications. This allowed the combined analyses of performance objectives and criteria, including cutting structure, rock type, application, well profiles, drives, and 3D contact. Simulations were then run to examine the performance of different cutting structures relative to various drilling parameters, and matched to a specific drive system. An optimized PDC bit design was developed and manufactured, and its field performance was compared to the model and to PDC bit performance in offset wellbores. The optimized design was manufactured in a 6 1/8-in PDC bit and run on motorized and non-motorized RSS. It resulted in significant ROP increases and a lower cost per foot compared to offset wells, while retaining a high level of steering response. In one well, the ROP was increased to 48.43 ft/hr versus a target of 35 ft/hr based on offset performance. The resulting cost per foot was reduced from $11.40 KD to $8.59 KD. The paper examines bit performance and dull condition for the runs and compares them with offset runs. Field performance results validate the bit design modeling and simulation process, and emphasize the importance of integrating various performance analyses to improve bit efficiency without degrading critical steering characteristics. Extensive development of cutting structures that "drilled on paper" combined with full scale bit laboratory testing has resulted in the development of a design process that combines multiple design objectives and criteria to model and simulate bit behavior during drilling. As shown by field results, this process of balancing the design provides the means to optimize overall performance and lower costs for many different bit applications.
In close collaboration with the operator, third party suppliers and the integrated drilling service contractor the first Integrated Drilling Project in Kuwait started in March 2016. The project is being treated as a pilot to assess the value integration can bring to the operator by providing the expertise, new technology and processes for managing drilling risks and improving performance. The project scope includes the provision of all services, engineering and supervision for the well construction process under a lump sum model. The project had an original target start date of June 2016, a year after the contract award. However, in the current challenging oil and gas industry environment, coupled with the operator's ambitious plans to increase oil production, the requirement for drilling more wells to provide the necessary increase in oil output meant that an early start would help in accelerating oil production from the Sabriyah and Raudhatain fields. From the onset, the target was set for exceeding client expectations. It required a very detailed planning approach to avoid potential short-sighted risks that could lead to costly delays. This paper describes the success case of advanced planning of a fully integrated approach. Three primary challenges were identified for the early startup, i.e. drilling rigs readiness, personnel and processes. For the drilling rigs readiness, the main issue was the utilisation of an interim rig requiring major equipment overhaul, including engines, top drive, mud pumps and drawwork, followed by an audit and certification. A specialised and dedicated team was mobilized to manage this operation successfully, and better support the rig contractor, including a rig contractor manager, rig managers, electricians and mechanics. Key project team members were brought in ahead of time, through careful selection to ensure the right competencies, according to the technical complexities and contract requirements. The team in place focused on implementing processes to accommodate operational and engineering optimizations as well as new technologies which could be applied from the first well, in order to improve well contruction cycle and deliver more wells in shorter time to the operator. This required collaboration from both teams including the integrated drilling service contractor and the operator. For ensuring the project readiness, a thorough process assessment was followed for each of the established milestones in the schedule. These assessments covered different functional areas including HSE, engineering, drilling services, third party providers, resources allocation and technology review including cost versus benefit analysis. In result, close collaboration and hard work of integrated team including operator, third party suppliers and integrated drilling service contractor, enabled successful project start-up. The drilling operations commenced three months ahead of plan, exceeding expectations of all project stakeholders.
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.