Value of Managing the Subsurface Risks and Uncertainties in the Project Execution; A Successful Case History in Merakes Green Gas Field Development

2021 ◽  
Author(s):  
Dian Kurniawan ◽  
Gabriela Carrasquero ◽  
Edo Richardo Daniel ◽  
Kurnia Wirya Praja ◽  
Elisa Spelta ◽  
...  

Abstract Implementing a proactive approach with comprehensive reservoir characterization, risks identification and mitigation are key elements that have to be deeply investigated before the project execution for achieving the optimum results in field development. A tremendous result on the seismic driven field development and synergy with a fast track development concept in Merakes green gas field has been achieved. In this paper, the conceptual and methodologies are described in the way of managing the subsurface risks and uncertainties during the planning and execution phase. A suitable example in Merakes field development which classified as "appraisal while developing", since the remaining risks still exist during development campaign, is presented. By having only two exploration wells with limited data, a robust upfront reservoir characterization and modeling were quite challenging to provide a reliable image of the subsurface condition. The enhancement on the way of constructing an integrated reservoir study prior to the field development is considered an essential requirement that has to be done before the project execution. A comprehensive approach that maximizes the integration of Geology, Geophysics and Reservoir Engineering disciplines and brings out the reservoir risk quantification has been considered as a basis and strategic driver for both subsurface quantitative description and de-risking of development wells locations. Focusing on the subsurface risk criticality, the compartmentalization, rock facies quality, gas-water contact depth and sand production were considered as the main critical aspects that could impact the final success. Preserving mitigation strategies and adapting development flexibility concept have been prepared to overcome such subsurface unexpected conditions. A description of the well placement strategy which widely open to be optimized during the drilling campaign was allowed and brought benefits in mitigating the compartmentalization risk. The readiness of an adequate and comprehensive data acquisition program including log data acquisition, coring and well testing in the development wells has been prepared. Moreover, a sidetrack contingency plan has been also considered for a key-well in case of worse than expected results. With know-how and experiences on the nearby field development, an extensive evaluation of water and sand production risks was derisked by selecting smart completion and sand control technologies. A holistic integration between subsurface, drilling, petroleum, facilities disciplines is considered of paramount importance in development projects. The awareness of the field's risks and uncertainties allows maximizing efforts in following up the drilling phase promptly adapting the data acquisition plan to the effective level of residual uncertainty and related development risk. Eventually the good match between the expected scenario and the actual well results allowed to cancel most of the costly data acquisition plans which contributed to a positive impact on the project cost and time-saving.

2020 ◽  
Vol 60 (1) ◽  
pp. 267
Author(s):  
Sadegh Asadi ◽  
Abbas Khaksar ◽  
Mark Fabian ◽  
Roger Xiang ◽  
David N. Dewhurst ◽  
...  

Accurate knowledge of in-situ stresses and rock mechanical properties are required for a reliable sanding risk evaluation. This paper shows an example, from the Waitsia Gas Field in the northern Perth Basin, where a robust well centric geomechanical model is calibrated with field data and laboratory rock mechanical tests. The analysis revealed subtle variations from the regional stress regime for the target reservoir with significant implications for sanding tendency and sand management strategies. An initial evaluation using a non-calibrated stress model indicated low sanding risks under both initial and depleted pressure conditions. However, the revised sanding evaluation calibrated with well test observations indicated considerable sanding risk after 500 psi of pressure depletion. The sanding rate is expected to increase with further depletion, requiring well intervention for existing producers and active sand control for newly drilled wells that are cased and perforated. This analysis indicated negligible field life sanding risk for vertical and low-angle wells if completed open hole. The results are used for sand management in existing wells and completion decisions for future wells. A combination of passive surface handling and downhole sand control methods are considered on a well-by-well basis. Existing producers are currently monitored for sand production using acoustic detectors. For full field development, sand catchers will also be installed as required to ensure sand production is quantified and managed.


2016 ◽  
Author(s):  
M. Zamberi ◽  
M. Mohd Sallehud-Din ◽  
S. Shaffee ◽  
N. Nik Kamaruddin ◽  
M. B. Jadid ◽  
...  

2021 ◽  
Author(s):  
Emily Ako ◽  
Erasmus Nnanna ◽  
Odumodu Somtochukwu ◽  
Akinmade Moradeke

Abstract Chemical Sand Consolidation (SCON) has been used as a means of downhole sand control in Niger Delta since the early 70s. The countries where SCON has been used include Nigeria (Niger Delta), Gabon (Gamba) and UK (North Sea). SCON provides grain-to-grain cementation and locks formation fines in place through the process of adsorption of the sand grains and subsequent polymerization of the resin at elevated well temperatures. The polymerized resin serves to consolidate the surfaces of the sand grain while retaining permeability through the pore spaces. In a typical Niger Delta asset, over 30% of the wells may be completed with SCON. A high percentage are still producing without failure since installation from1970s. Where the original SCON jobs have failed, re-consolidation has also been carried out successfully. Chemical Sand Consolidation development has evolved over the years from: Eposand 112A and B, Eposand 212A and B, Wellfix 2000, Wellfix 3000, Sandstop (resin based), Sandtrap 225, 350 & 500 (resin based) and lately Sandtrap 225,350, 500 (solvent based) and Sandtrap ABC (aqueous based). There have been mixed results experienced with the deployment of either of the latest recipes of SCON. This was due to the fact that the conventional deployment work procedure was followed with the tendency for one-size-fits-all approach to the treatment. This paper details the challenges faced with sand production in ARAMU037, the previous interventions and how an integrated approach to the design and delivery of the most recent intervention restored the way to normal production. The well has now produced for about 2 years with minimal interruption with the activity paying out in less than 6 months. The paper also recommends the best practice for remedial sand control especially for wells in mature assets.


2010 ◽  
Vol 50 (1) ◽  
pp. 623 ◽  
Author(s):  
Khalil Rahman ◽  
Abbas Khaksar ◽  
Toby Kayes

Mitigation of sand production is increasingly becoming an important and challenging issue in the petroleum industry. This is because the increasing demand for oil and gas resources is forcing the industry to expand its production operations in more challenging unconsolidated reservoir rocks and depleted sandstones with more complex well completion architecture. A sand production prediction study is now often an integral part of an overall field development planning study to see if and when sand production will be an issue over the life of the field. The appropriate type of sand control measures and a cost-effective sand management strategy are adopted for the field depending on timing and the severity of predicted sand production. This paper presents a geomechanical modelling approach that integrates production or flow tests history with information from drilling data, well logs and rock mechanics tests. The approach has been applied to three fields in the Australasia region, all with different geological settings. The studies resulted in recommendations for three different well completion and sand control approaches. This highlights that there is no unique solution for sand production problems, and that a robust geomechanical model is capable of finding a field-specific solution considering in-situ stresses, rock strength, well trajectory, reservoir depletion, drawdown and perforation strategy. The approach results in cost-effective decision making for appropriate well/perforation trajectory, completion type (e.g. cased hole, openhole or liner completion), drawdown control or delayed sand control installation. This type of timely decision making often turns what may be perceived as an economically marginal field development scenario into a profitable project. This paper presents three case studies to provide well engineers with guidelines to understanding the principles and overall workflow involved in sand production prediction and minimisation of sand production risk by optimising completion type.


2021 ◽  
Author(s):  
Thivyashini Thamilyanan ◽  
Hasmizah Bakar ◽  
Irzee Zawawi ◽  
Siti Aishah Mohd Hatta

Abstract During the low oil price era, the ability to deliver a small business investment yet high monetary gains was the epitome of success. A marginal field with its recent success of appraisal drilling which tested 3000bopd will add monetary value if it is commercialized as early as possible. However, given its marginal Stock Tank Oil Initially in Place (STOIIP), the plan to develop this field become a real challenge to the team to find a fit-for-purpose investment to maximize the project value. Luxuries such as sand control, artificial lift and frequent well intervention need to be considered for the most cost-effective measures throughout the life of field ‘Xion’. During field development study, several development strategies were proposed to overcome the given challenges such as uncertainty of reservoir connectivity, no gas lift supply, limited footprint to cater surface equipment and potential sand production. Oriented perforation, Insitu Gas Lift (IGL), Pressure Downhole Gauge (PDG), Critical Drawdown Pressure (CDP) monitoring is among the approaches used to manage the field challenges will be discussed in this paper. Since there are only two wells required to develop this field, a minimum intervention well is the best option to improve the project economics. This paper will discuss the method chosen to optimize the well and completion strategy cost so that it can overcome the challenges mentioned above in the most cost-effective approach. Artificial lift will utilize the shallower gas reservoirs through IGL in comparison to conventional gas lift. Sand Production monitoring will utilize the PDG by monitoring the CDP. The perforation strategy will employ the oriented perforation to reduce the sand free drawdown limit compare to the full perforation strategy. The strategy to monitor production through PDG will also reduce the number of interventions to acquire pressure data in establishing reservoir connectivity for the second phase development through secondary recovery and reservoir pressure maintenance plan. This paper will also explain the innovative approaches adopted for this early monetization and fast track project which is only completed within 4 months. This paper will give merit to petroleum engineers and well completion engineers involved in the development of marginal fields.


2021 ◽  
Author(s):  
Gaurav Agrawal ◽  
Moustafa Eissa ◽  
Kamaljeet Singh ◽  
Shaktim Dutta ◽  
Apoorva Kumar ◽  
...  

Abstract The consequences of sand production are often disadvantageous to the short and long-term productivity of the well. Although some wells routinely experience controllable sand production, these are the exception rather than the rule. Sand production and its management over the life of the well is not an attractive situation but is often essential to extract the resource. Knowing the root cause behind sand inflow in a well and the possible results can inform an appropriate strategy to safely extract as much of the resource as possible. The sands in such reservoir units often have high permeability and are mechanically weak and prone to sand production. The producing wells are often completed with gravel-packed completions for efficient sand control. Most of the wells have multi-zone completions for better productivity but this further complicates reservoir characterization. This paper describes the first use of downhole sand impact detection technology in such fields. The sand detection technology integrates the fully digitized high-resolution acquisition with signal processing and interpretation algorithm to enhance the sand particle detections as small as 0.1 mm in diameter and up to 1,500 impacts per second. The tool is designed to immune the sensors from any background noise and gas/liquid jetting effect. A combination of production logging tools (PLT) and the sand impact detection tool, was used to understand four phase zonal contributions (gas, oil, water and sand) and pinpoint sand entry in these cases. Results exceeded expectations and the ability for the sand detection tool to accurately detect the point of sand entry enabled immediate intervention to eliminate sand production in these case studies. One of them also resulted in increased production of 7.4kb/d oil without any sand flow and with greatly reduced gas-oil ratio as compared to pre-intervention production. The work clearly demonstrates the practical and effective use of downhole sand impact detection with new sand detection technology to identify and isolate sand production in wells. The innovative tool design makes it feasible to detect even small sand particles in adverse wellbore conditions and varied production rates, thus adding a detection of the fourth phase in an otherwise three phase production log.


2021 ◽  
Author(s):  
Danny Hidayat ◽  
Rantoe Marindha ◽  
Triantoro Ade Nugroho ◽  
Reyhan Hidayat ◽  
Runi Kusumaning Rusdi

Abstract Peciko Field currently produces gas from multilayer sand-prone shallow reservoirs. Therefore, it needs sand control method to unlock these marginal reservoirs through low-cost intervention. Hanging screen has been reviewed as an alternative solution to minimize sand control cost while maintaining its robustness to maximize the recovery. This paper will present and evaluate the hanging screen installation and performance from subsurface to surface elements in Peciko field. Hanging screen implementation in Peciko will be evaluated in terms of ease of installation to its performance during production phase. Peciko wells are equipped with real-time monitoring system including Acoustic Sand Detector. Therefore, sand problems could be easily identified. Any indication of screen failure will be confirmed by checking the surface equipment like chokes and intrusive probes. Further intervention to retrieve the screen and perform visual check at surface can be executed to extend the verification. Filter size, placement method, clean-up, and sand sieve result will be gathered to identify the root cause and determine the best method to apply hanging screen as reliable sand control method. Nine installations in 2019 conclude that screen plugging, liquid loading, and combination of both are main issues in production phase. With three plugging cases from well Fx and E2x, it was found that excessive drawdown pressure triggers high gas velocity in perforation tunnel and causing excessive sand production that plugged the screen. These cases also prove that self-unloading by choke movement can lead to plugging if the drawdown pressure and gas rate are not monitored carefully. Commingle production in Ax becomes an issue in lifting performance when reservoir pressure declines and liquid was produced from several reservoirs. Limiting drawdown pressure gives smaller gas rate to lift the liquid and make the well died from liquid loading easily. Massive sand production in well E2x and E2y cause an increase in Top of Sediment (TOS) and lead to inaccessible screen even with multiple bailing attempts. A series of screen design, choke configuration, proper clean-up and continuous monitoring are critical steps to be performed prior and after screen installation to maintain production lifetime. With average stakes of 0.2 Bcf per well, hanging screen has proven to produce 67% of the well reserves in shallow reservoirs. This value creation led to the conclusion that hanging screen is an economically-feasible-sand control method to be implemented in Peciko.


SPE Journal ◽  
2011 ◽  
Vol 16 (02) ◽  
pp. 463-481 ◽  
Author(s):  
Gang Han ◽  
Keith Shepstone ◽  
Iwan Harmawan ◽  
Ufuk Er ◽  
Hasni Jusoh ◽  
...  

Summary An offshore gas field has been producing sand for a few years. Sand production has been closely monitored through acoustic flowline devices and a sand-collection system installed on the platforms. Observation of sand production has triggered evaluation of whether to install surface desanders or to complete future wells with downhole sand control. This evaluation requires a prediction of sanding rate over the reservoir life. The possibility of providing downhole sand control on existing wells was also evaluated in separate studies. Predicting sanding rate, particularly for gas fields, has been historically challenging, mainly because of the sporadic nature of sand production, inadequate quantification of fundamental physics, and lack of representative laboratory tests and reliable field calibration. To tackle these challenges, four studies have been designed and executed: (1) the development of a reliable log-based rock-strength estimate, (2) the prediction of sanding rate over the reservoir life for a conservative well condition, (3) the evaluation of sand-particle transport from the reservoir to the surface facilities, and (4) the estimate of potential erosion of platform facilities. The sanding-rate prediction is based on extensive laboratory tests of four carefully selected whole cores with gas and water flow. It then has been validated by field-monitoring data from an acoustic flowline device on each producer and a sand-collection system on the platforms. The studies have provided a prediction of (1) future sand production, (2) how much of the produced sand will be seen at the surface (and, therefore, how much of it will fall into the rathole), (3) how fast various components of the surface facility will erode over the field life, and (4) what will be the optimal completion strategy for sand control should it become necessary. They have provided input to an integrated evaluation of completion design, reservoir management, platform configuration, and field economics.


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