The Haradh Increment-3 (HRDH Inc-3) development, commissioned in March 2006, has added significant volumes to Saudi Aramco's daily production capacity. The development has 73 wells comprising of 28 water injectors, 13 observation and 32 producers. 28 of the 32 producers are intelligent completions in multilateral wells. The Maximum Reservoir Contact (MRC) wells with multilateral systems improve the reservoir contact while reducing the drawdown on the reservoir. The intelligent completion system allows the inflow from each lateral to be controlled from the surface without well intervention. The combination of the multilateral and intelligent completion system is expected to enhance field recovery by preventing/delaying water coning and improving sweep efficiency. HRDH Inc-3 may be considered as a milestone in the industry where the field development is focused on the "Smart Multilateral Systems" Application of cutting edge technologies like rotary steerables system (RSS), realtime drilling data transmission, Geosteering, non damaging fluids, multilateral systems and intelligent completions have helped in achieving maximum effective reservoir contact and delivering the wells ahead of schedule. The producer wells were drilled with three or four laterals depending on the location of the well. Each of the laterals has around 4,000 ft of reservoir contact and the average reservoir contact for each well is over 14,000 ft. The wells are constructed as Technology Advancement in Multi-Lateral (TAML) Level-2 system where openhole laterals are drilled out of the motherbore that is cased and cemented. The intelligent completion system comprises of pressure and temperature sensors, production packers and hydraulically operated downhole valves that can be controlled from the surface. The downhole valves are placed in the motherbore to control inflow from each lateral. The paper presents details of the field planning, drilling and completion practices. The challenges faced in drilling and completing these complex multilateral MRC wells within a tight schedule and the important lessons learned will also be covered in the paper Introduction HRDH Inc-3 is the southern most part of the greater Ghawar field. See figure 1 The Arab-D reservoir in Ghawar comprises the basal portion of the Upper Jurassic Arab Formation and is composed of a lithological couplet of carbonate and overlying anhydrite, which represents a cyclic transition upwards from shallow marine carbonates through marginal marine evaporates. In terms of flow mechanism, the fracture corridors, coupled with stratiform super permeability play a relatively significant role in recovery and pressure support. Initial developments at Haradh Increment-1 used conventional vertical wells and Haradh Increment-2 was development with long horizontal wells. Advancement in technology has enabled HRDH Inc-3 to be developed with MRC wells and SmartWells™. SmartWells™ in multilaterals or smart laterals are a combination of SmartWells™ completion in conjunction with multilaterals wells. In this application, the SmartWells™ system consisting of surface controlled downhole control choke, isolation packers and pressure/temperature sensors are placed in the motherbore and provides the ability to remotely control the inflow from each lateral. Figure 2 shows an illustration of the intelligent completion in a multilateral well The drilling and completion of the wells were preceded by a full field evaluation consisting of fluid flow behavior, displacement mechanism, sweep efficiency and well performance modeling ref 1. Studies have shown that multilateral MRC wells with SmartWell™ completion will prolong the life of the wells, reduce the decline rate and minimize water handling. The water production on the total field basis was reduced compared to the field case without smart wells. A Formation Damage and Wellbore Clean-Up team was created to review the drilling fluid and provide a drill-in fluid design and set of fluid parameters to maintain while drilling each lateral ref 2. The team also suggested practices to maintain mud quality and procedures for wellbore clean-up. A Geosteering team comprising of drilling engineers, reservoir engineers, geologists and petrophysicists were created to enhance the geosteering process and streamline the decision making process at the 24/7 Geosteering Operation Center (GOC). The development was started in February 2005 with the 28 water injection wells at the periphery of the field. Also, 13 dedicated observation wells were drilled and completed with permanent downhole gauges to monitor the fluid front movement in the reservoir. The first producer well was drilled in October 2005.
A geomechanical study was conducted for one of the drilling platforms in offshore Saudi Arabia, where several highly deviated (well inclination > 80°) development wells were planned. The main objective was to provide safe mud weight ranges and predict possible problematic depths to minimize drilling challenges like pack-off, stuck-pipe, lost in hole, over-pulls etc., which are likely due to wellbore instability. The scope of this work was restricted to the curve section of the planned wells because most of the problematic formations, comprising mainly shale and weak interbedded sand formations, are encountered in the curve section. The operator's drilling department sought a clear understanding of the geomechanical aspects of these problematic formations to optimize the drilling plan and minimize nonproductive time. A 1D mechanical earth model (MEM) was constructed using openhole log data available from the only exploratory well drilled on this platform. The 1D MEM was further used in conducting post-drilling analyses to validate and history match events related to wellbore instability (like tight spots, pack-off etc.,) that were observed while drilling and stress-related wellbore failure as shown by the calipers. The developed model was used for analyzing planned well trajectories and providing mud weight window limits to safely drill the highly deviated planned wells. Sensitivity analysis was performed to identify the well inclination limits to drill across the problematic zones whilst minimizing issues related to wellbore instability. The developed geomechanical model was validated using the log data acquired during drilling each of these inclined wells; the predictions from the model were in close agreement with actual observations during drilling. The outcome of this study helped optimize the well design for upcoming wells in this field. Using the recommendations provided from this study, several highly deviated development wells were successfully drilled and completed. Apart from standard failure analysis, ‘depth of failure’ approach was also taken into account to provide recommendations on optimum drilling mud weight. Utilizing the geomechanical study, extended reach curve sections as long as 5000-ft measured depth (MD) were planned and drilled successfully without any significant nonproductive time (NPT).
Environmental regulations for oil and gas companies have become increasingly stringent with particular focus on remote areas and environmentally sensitive terrestrial and marine locations and the preservation of natural habitats and resources. With this in mind, many regulatory agencies have adopted "zero discharge" policies requiring monitored disposal of all wastes generated from drilling operations. For designated drilling operations, the various waste streams include: drill cuttings, excess drilling fluid, contaminated rainwater, produced water, scale, produced sand, and even production and cleanup waste. Traditional practices range from onsite pit burial to temporary box storage and hauling of the waste products to a final disposal site. Environmental risks from accidental releases and gas emissions result in higher operating costs and present concerns and liabilities as disposal sites are often several kilometers (km) from the generation source. Cuttings re-injection (CRI) is a safe and cost-effective alternative that provides permanent and contained disposal of drilling cuttings in an engineering-determined subsurface formation. CRI provides a reliable method for achieving "zero discharge" by injecting slurrified cuttings and associated fluids into hydraulically created fractures up to several thousand meters below the surface. This disposal technique helps mitigate environmental risks and future liabilities associated with potential surface contamination. This paper outlines the first successful application of CRI technology in the offshore areas of Saudi Arabia as a cost-effective and environmentally friendly waste management technique. Details of CRI theory as well as best practices, challenges and lessons learned are presented in detail from initial engineering design to case study utilization. This high pressure CRI work was the first of its kind in the MENA region.
This paper presents a case example to illustrate how a consistent geomechanical approach and coherent data integration are used to provide the basis for the evaluation of formation mechanical properties, characterization of in-situ stresses, identification of wellbore failure mechanisms, and calibration of a wellbore stability model. The calibrated model is then used in conjunction with the proposed build-and-hold and catenary well profiles to generate the mud weight windows for an ERD well. To provide further insight into the wellbore stability with respect to wellbore trajectories and in-situ stresses, contour plots of mud weights are generated for a critical depth interval. These contour plots delineate potential instability areas and are critical for predrilled well trajectory designs. Additionally, an innovative approach to establish the lower limit of mud weight for wells that cannot be drilled without failure zones (breakouts) forming around the wellbore is presented. This approach enables difficult wells to be drilled, with the lower mud weight reducing the risk of formation damage and increasing the rate of penetration. Introduction Resak Field, located offshore of Peninsula Malaysia, is operated by PETRONAS Carigali Sdn. Bhd. (PCSB). The field is currently under development and 13 wells will be drilled radially from a production platform in a ‘bow-tie’ pattern. In order to cost effectively drain the proven reserves without having to add a lightweight structure and pipelines connecting to the processing platform, some of the development wells will be drilled extended-reach. Resak LOC-11 is an extended-reach well designed to drain the southeastern portion of the field reserves. Two wellbore trajectories, build-and hold and catenary, were proposed. Fig. 1 and Fig. 2 show the schematics for the two well plans. Extended-reach drilling (ERD) can be extremely costly if not optimally designed. Occurrences of borehole instability-related problems, such as stuck pipes, fishing and sidetracking operations, have been reported to increase with increasing wellbore inclinations1 and extended-reach drillings. In addition to escalating costs, wellbore instability can also result in poor hole conditions, which ultimately would affect the quality of reservoir characterization and the effectiveness of primary cementing. Poor primary cementing in high angle gas wells is of particular concern because of possible gas migration during cement setting. Faced with the challenges of delivering the well within AFE, the Resak project team decided to conduct the wellbore stability assessment for the proposed ERD well. The results of the geomechanical analysis will be used to:decide which wellbore trajectory, andestablish the mud weight program that will mitigate wellbore instability and improve operational performance. An extensive in-house database is available through comprehensive data acquisition programs during the exploration and appraisal phases. Due to the data quality of older wells, only the most recent appraisal well data (Resak 6F-18.4) was selected to provide the basis for rock mechanical properties and in-situ stress characterizations as well as wellbore stability model calibrations. The calibrated model was then used in conjunction with LOC-11's well plans (hole deviations and azimuths) to generate the stable mud weight profiles. The safe operating mud weight window can then be implemented together with good oilfield drilling practices to mitigate potential borehole instability-related problems. The purpose of this paper is to present a consistent geomechanical approach for developing the optimal mud weight program for LOC-11 ERD.
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