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Collaborating Authors
Drillstem/well testing
Abstract In recent publications, it has been observed that shale gas wells behave like a linear dual porosity system. In this paper, a linear dual porosity model is utilized assuming matrix rock as the main primary porosity that feeds a hydraulic fracture, which acts as a secondary porosity system and primary flow conduit. The paper demonstrates the practical application of the type curve analysis method for shale gas and shale oil published by Abdulal, Samandarli and Wattenbarger (2011). The technique utilizes the actual well performance to obtain a type curve match that allows determination of the parameters required to quickly determine the completion/fracture effectiveness and allow projection of the long-term well production performance. In this paper, the ideal application of the type curve method with calculation procedures is presented with two actual field examples. Field Case 1 demonstrates the type curve matching followed by the procedure used to calculate dual porosity parameters like effective fracture permeability, drainage volume and the area of the interfaces between the hydraulic fractures and the rock matrix. These parameters can be used to evaluate the well completion with its associated hydraulic fracture effectiveness. Field Case 2 is included to illustrate the method limitations and potential pitfalls when applying this type curve approach.
- North America > United States > Texas (0.69)
- Asia > Middle East > Saudi Arabia (0.69)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.69)
- North America > United States > South Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > North Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > Montana > Williston Basin > Bakken Shale Formation (0.99)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
Abstract This paper presents a comprehensive pressure transient analyses (PTA) based dynamic reservoir characterization of a mature giant carbonate oil field. An important part of an integrated reservoir study is to reconcile differences between the static and dynamic models. In this study, a large number of well tests were analyzed and integrated with other field data. The current study highlights the paramount importance of PTA for a refined reservoir description, including permeability modeling and characterizing intersecting or nonintersecting conductive fractures and faults across the field. This well tests data review has also broadened the field dynamics understanding along with the strengths of the synergic multidisciplinary approach as the PTA data is integrated with other reservoir characterization data types. The subject field is composed of two naturally fractured reservoirs separated by a thick non-permeable zone. The Upper reservoir is prolific, while the Lower reservoir is relatively tight and highly fractured. Early pressure data confirms communication between the two reservoirs through several large scale fractures crossing the thick non-permeable zone. For the purpose of this study, the field has been divided into several areas, with representative well data from both the Upper and Lower reservoirs. Pressure buildups from multi-well groups, generally conducted as single-phase (before water breakthrough), were analyzed by advanced analytical and/or numerical models. The selected interpretation model was dependent on the reservoir complexities diagnosed from the derivative plots. The analyses provided valuable well parameters, such as flow capacities and productivity indices, which are critical as input for permeability modeling and simulation model history-matching. Subsequently, equally important is the detection of reservoir description events that can be observed from the PTA response, e.g., areas of inter-reservoir communication, super permeability zones or quantification of fracture characteristic parameters. The presented case study includes well examples of the major observed field reservoir features.
- North America > United States (1.00)
- Asia > Middle East > Iraq > Diyala Governorate (0.41)
- Asia > Middle East > Saudi Arabia > Eastern Province > Khobar (0.15)
- Geology > Geological Subdiscipline (0.69)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (0.47)
- Asia > Middle East > Saudi Arabia > Eastern Province > Al-Ahsa Governorate > Arabian Basin > Widyan Basin > Ghawar Field > Lower Fadhili Formation (0.99)
- Asia > Middle East > Saudi Arabia > Eastern Province > Al-Ahsa Governorate > Arabian Basin > Widyan Basin > Ghawar Field > Khuff D Formation (0.99)
- Asia > Middle East > Saudi Arabia > Eastern Province > Al-Ahsa Governorate > Arabian Basin > Widyan Basin > Ghawar Field > Khuff C Formation (0.99)
- (4 more...)
- Information Technology > Modeling & Simulation (0.35)
- Information Technology > Databases (0.34)
This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 148575, ’Challenging Well-Testing Operations in High-Temperature Environments - Worldwide Experiences and Best Practices Learned,’ by Alejandro Salguero, SPE, Edgar Almanza, and Josmar Haddad, SPE, Halliburton, prepared for the 2011 SPE/IADC Middle East Drilling Technology Conference and Exhibition, Muscat, Oman, 24-26 October. The paper has not been peer reviewed. High-temperature (HT) wells are classified as those with bottomhole temperatures in excess of 300°F. New technologies and advances in the industry (e.g., gauges, downhole equipment, and samplers) have been applied to improve decision-making capabilities and to increase well-testing-evaluation success, even in extreme and challenging environments. These enhancements enable improved economics and operational efficiency along with better safety conditions for the involved personnel and lower environmental risk during testing operations. Introduction Well testing is a reliable, dynamic method of retrieving and collecting a variety of information from the reservoir, including permeability, formation damage, bottomhole pressure and temperature, fluid samples, and production quantification. The methods and equipment used to collect these data have evolved as exploration has moved into more-demanding and -challenging environments. In recent years, high-pressure/high-temperature (HP/HT) wells have become more common, and they required new techniques that support the environmental challenges. Proper planning and personnel and qualified equipment are key to achieve successful well-test results, especially considering that well and reservoir conditions can change easily from one region to another, adding challenges to the evaluation operation. HT prospects are defined as wells having bottomhole temperatures in excess of 300°F, and extreme HT wells are prospects having bottomhole temperatures of 350 to 400°F. The chart in Fig. 1 depicts designations for each pressure and temperature definition. Most HT cases have required the use of a deep-well simulator to test and qualify/certify equipment for the expected well-test conditions. The complete paper details three cases of testing wells with temperatures ranging from 340 to 430°F. These cases were carried out in different geographical locations. These wells were chosen because different bottomhole configurations of full-scale downhole assemblies were used. It is important to mention that special tools and equipment are available to perform operations under extreme conditions (e.g., 450°F and 20,000 psi). Currently, electronic memory gauges used in drillstem-test (DST) equipment are designed and tested to work in conditions of 400°F and 30,000 psia. Real-time gauges are available that have been tested to 350°F. However, when more-challenging conditions are encountered, mechanical pressure and temperature gauges must be used.
This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 147247, ’Successful Discovery of Light Oil From an Unsuccessful Paleozoic Well Through Re-Entry - A Case Study of an HP/HT Well,’ by Haifa Al-Bader, SPE, Yousef Zaid Al-Salali, SPE, Vidya Sagar Duggirala, SPE, A. Manimaran, and S. Packirisamy, SPE, KOC, prepared for the SPE Annual Technical Conference and Exhibition, Denver, 30 October-2 November 2011. The paper has not been peer reviewed. An exploratory well, the second deepest in Kuwait, had been drilled in the Mutriba field to 22,094 ft. Two formations, Kra-Almaru and Khuff, were perforated and tested. The tests revealed the presence of sparse gas, and it was decided to test and complete this well in the Jurassic formation through re-entry. The re-entry in this ultradeep well was full of challenges; however, by overcoming all the challenges, this well was successfully perforated, stimulated, and tested, which led to the first commercial discovery of oil and gas within the Jurassic reservoir in the Mutriba field. Introduction Two zones in Paleozoic and Triassic sections were perforated and tested separately to evaluate the presence of hydrocarbon between 18,500 and 21,500 ft. The well was completed in 2004. After undesirable results were obtained from the Triassic and Paleozoic formations, exploration teams studied the feasibility of testing Jurassic formations in this well through re-entry. Testing Jurassic formations in the Mutriba field from an existing well will be more economical than drilling a new well. A snubbing unit was deployed in 2008. In 2009, a suitable workover rig was deployed to test Jurassic formations in this previously drilled well. The location of the Mutriba field is shown in Fig. 1. A snubbing unit had been used to isolate the open perforations of the Triassic zone with cement. Subsequently, a workover rig was deployed to test the prospect of a Jurassic reservoir. Testing the Jurassic reservoir behind two heavy-walled casings (7 in. 46.4 lbm/ft and 8⅝ in. 40 lbm/ft) combined with extreme sour and high-pressure/high-temperature (HP/HT) conditions warranted high health, safety, environment, and technical precautions. Challenges for re-entry to this well included HP/HT conditions, a high surface pressure, and well-killing issues. Testing of the formation fluid revealed the presence of an unexpectedly high concentration of H2S (20%) and CO2 (2%), which presented challenges for coiled-tubing (CT) operations, stimulation, flowing the well, and fluid disposal.
- Asia > Middle East > Kuwait > Northwest Kuwait (0.87)
- Asia > Middle East > Israel > Haifa District > Haifa (0.25)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > HP/HT reservoirs (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- (2 more...)
Development of a Fuzzy System Model for Candidate-well Selection for Hydraulic Fracturing in a Carbonate Reservoir
Zoveidavianpoor, Mansoor (Universiti Teknologi Malaysia, Faculty of Petroleum and Renewable Energy Engineering) | Samsuri, Ariffin (Universiti Teknologi Malaysia, Faculty of Petroleum and Renewable Energy Engineering) | Shadizadeh, Seyed Reza (Petroleum University of Technology, Abadan Faculty of Petroleum Engineering)
Abstract With current technology, it is only possible to extract 20% to 25% of the original oil in place from Iranian carbonate reservoirs, 10% less than the world average. In addition, formation damage is a serious problem in those reservoirs, which mainly caused by asphaltene precipitation, sand production, and ineffective stimulation method. The majority of mature carbonate reservoirs in Iran have low permeability and high skin values. Therefore, such reservoirs are capable of producing at commercial rates only if they are hydraulically fractured. Acid fracturing is usually reported as a standard method for fracturing in carbonate reservoirs. Hydraulic Fracturing (HF) technology, which was originally applied to overcome near wellbore damage, is a proper replacement stimulation method. It is evident that to adopt this technology, considerable efforts have to be strenuous in candidate-well selection. As asserted in the literature, even though a common practice, candidate-well selection is not a straightforward process and up to now, there has not been a well-defined approach to address this process. The techniques applied in HF candidate-well selection could be divided into two methods; conventional and advanced approaches. Conventional methods are not easy to use for nonlinear processes, such as candidate-well selection that goes through a group of parameters having different attributes and features such as geological aspect, reservoir and fluid characteristics, production details, etc. and that’s because it is difficult to describe properly all their nonlinearities. However, it is believed that advanced methods such as Fuzzy Logic (FL) could be better decrease the uncertainty existed in candidate-well selection. This paper presents a Mamdani fuzzy model where rules for HF candidate-well selection were derived from multiple knowledge sources such as existing literature, intuition of expert opinion to verify the gathered information. The needs for adapting HF as replacement stimulation in Iranina carbonate reservoirs are discussed and advanced methods for HF candidate selection will be reviewed in this paper. Also, the main reasons which show why propped HF is the choice in carbonate reservoirs will be discussed. Finally, the proposed Fuzzy system model is applied along with a case study in a carbonate reservoir.
- North America > United States > Texas (1.00)
- Europe (1.00)
- Asia > Middle East (0.88)
- (2 more...)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (0.93)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.46)
- Oceania > New Zealand > North Island > Taranaki Basin (0.99)
- North America > United States > Wyoming > DJ (Denver-Julesburg) Basin > Codell Formation (0.99)
- North America > United States > Utah > Uinta Basin > Altamont-Bluebell Field (0.99)
- (31 more...)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- (2 more...)
Abstract The proven and most suitable stimulation technology to increase production in a tight sandstone formation is hydraulic fracturing. The hydraulic fracturing treatment will create a fracture and then keep it open by proppant, hence a conductive path allowing more oil and gas to be produced. Hydraulic fracturing operations in an offshore environment are sometimes considered as a costly solution and non-economic. An alternative economic solution, Fracture Assisted Sandstone Acidizing (FASSA), was evaluated. Sandstone acidizing is a method to increase oil production, by injection of compatible acid system at matrix rate, below the formation fracture gradient. This stimulation method is most suitable to remove near wellbore damage in medium-high formation permeability. To improve the effectiveness of the acid treatment in tight sandstone reservoir, a hydraulic fracture was created prior to the sandstone acidizing. Besides removing the near wellbore damage, the acid is expected to react with fracture face in sandstone and create a conductive path for oil to flow. Four successful jobs have been performed to date. This paper will describe planning, process, acid treatment selection, operation summary, and evaluation of success or failure of the treatment. In the future we also propose to perform similar treatments for a tight reservoir without having to pull out the existing completion.
- Europe > Norway > Norwegian Sea (0.25)
- Asia > India (0.16)
- Well Completion > Hydraulic Fracturing (1.00)
- Well Completion > Acidizing (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
Offshore Drilling & Well Testing Of A HPHT Gas Well: A Case Study
Shah, Prerak H (Gujarat State Petroleum Corporation Limited (GSPC)) | Pandya, Harsh T (Gujarat State Petroleum Corporation Limited (GSPC)) | Sharma, Harsh (Gujarat State Petroleum Corporation Limited (GSPC)) | Saxena, Arpit (Gujarat State Petroleum Corporation Limited (GSPC))
Abstract With exploration in harsh environments and consequent high pressure and temperature conditions, the calculation of reservoir properties has become complex and thus the changes in pressure transient response need to be understood and appreciated by taking appropriate challenging measures. The paper deals with the various challenges arising when dealing with the drilling and testing of HPHT gas wells with Hydrogen sulfide and Carbon dioxide, located in Krishna Godavari (KG) Basin and the difficulties faced while executing it. The paper focuses on the experience while drilling the reservoir with a different mud program and mechanical failure caused by HPHT conditions & highly corrosive environment. The paper also highlights the preference of SOBM over WBM while drilling the reservoir section. It also describes the learning process as the exploratory well campaign progresses from one well to other. It briefs about the challenges while performing MDT as per the program in these high temperature environment. The paper briefs about the decision involved in selection of proper grade tubing, elastomer, packer, flowhead equipments, DST tools & explosives in this HPHT environment along with Hydrogen sulfide & Carbon Dioxide. In any gas well testing, exhaustive amount of data over the requisite period of time are necessary; data redundancy necessitates redressing of equipments. The biggest challenges faced by industry are high temperature rather than high pressures, so making metallurgy an important basis of consideration. It also highlights about the method followed during correlation of prospective zones using different logs. The paper discusses the unexpected results and observations obtained during execution of our program and the lessons learnt from it.
- Geology > Mineral (1.00)
- Geology > Geological Subdiscipline (0.68)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.30)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.34)
Estimating Well Deliverability in Deepwater Wells With Interval Pressure Transient Testing (IPTT): A Case Study
Sundaram, K. M (Oil and Natural Gas Commision Limited) | Kumar, Nitish (Schlumberger) | Nangia, Viraj (Schlumberger) | Desphande, Vaibhav (Schlumberger) | Nahar, Siddhartha (Schlumberger) | Jackson, Richard (Schlumberger)
Abstract Deepwater is an extremely cost-intensive exploration frontier representing a high-risk/high-reward scenario. After the world’s largest deepwater gas discovery in on the east coast of India, the area has attracted several operators and activity has picked up considerably in recent years. Currently, five deepwater rigs and drillships are operating in water depths ranging from 1500 m to 3000 m. This cost-intensive scenario dictates the use of techniques which maximize quality information while minimizing rig time. Interval pressure transient testing (IPTT) on wireline and conventional testing acquire essentially the same data and use the same analytical tools. Conventional well testing methods obtain the average properties of multiple layer systems but turn out to be time-consuming and hence expensive, especially if the fluid is only water. However, wireline acquisition is much more appropriate for accessing multiple layers and is far less time consuming; additionally, it can be carried out in open holes as well. The radius of investigation identified by the progressive pressure transient is sufficiently large to determine essential reservoir properties. With IPTT, the evaluation can be made layer-wise, and these evaluations are very critical for both the exploration and appraisal stages of the field development. IPTT has been performed in deepwater wells in India using the dual-packer configuration of wireline formation testers. IPTT is used to evaluate reservoir parameters, capture representative fluid samples, and assess commercial viability and flow potential for multiple reservoir intervals. This potentially eliminates the need for conventional well testing on expensive deepwater rigs, thus significantly reducing operating cost by use of state-of-the-art technology. This paper showcases the workflow and process involved in the impact area of formation evaluation from a reservoir dynamics perspective and use of a calibrated, continuous permeability curve in calculations of full well deliverability in case of gas discovery.
- Geology > Mineral (0.95)
- Geology > Geological Subdiscipline (0.68)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Pressure transient analysis (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
Abstract Hydraulic fracture design is an example of what is largely a manual process that requires interaction with a number of different software applications to obtain fracture geometry, production constraints, production sensitivity criteria, and NPV scenarios. When the goal is an optimized fracture design, the process is especially onerous, as it requires iterative interactions with reservoir simulators, nodal programs, economics models, drilling-well design systems, and stimulation design tools to arrive at a suitable design. Previous papers have detailed the benefits that can be derived from the automation of operations, engineering workflows, and production workflows in general. A major service company was able to quickly provide workflow automation benefits to an East Texas field with the aid of its workflow automation software. In the East Texas field, the service company was able to preserve the provided business service, yet change many of the connections with other software applications that were used to deliver the business benefit, as well as the engineering methods used to optimize the design. The GoM Lower Tertiary Wilcox Sand Field was also deemed a good candidate by a major service company to operational and production workflow automation, given its low PI, high-cost wells, HPHT tech challenges, and production uncertainty. This fracture workflow uses a unique holistic combination of tools, which are coupled in a way as to reflect the actual economic values of various fracture scenarios. With the Microsoft Upstream Reference Architecture (MURA) initiative, Microsoft, along with several of its E&P partners, prescribes this approach, which focuses on achieving a level of interoperability between software solutions used by the industry.
- North America > United States > Texas > Upshur County (0.45)
- North America > United States > Texas > Smith County (0.45)
- North America > United States > Texas > Rusk County (0.45)
- (2 more...)
- North America > United States > Texas > East Texas Salt Basin > East Texas Field > Woodbine Formation (0.99)
- North America > United States > Texas > East Gulf Coast Tertiary Basin > Wilcox Play > Wilcox Play Formation (0.99)
- North America > United States > Louisiana > East Gulf Coast Tertiary Basin > Wilcox Play > Wilcox Play Formation (0.99)
- North America > United States > Gulf of Mexico > Gulf Coast Basin > Wilcox Trend Formation (0.99)
Abstract In the last decade, evaluations, discussions, workshops, and sharing of experiences have helped increase the number of intelligent well system (IWS) solutions being installed around the world. The intelligent wells offer many advantages over conventional completions. These primarily range from accelerated production, increased recovery, reduced or eliminated intervention, and improved reservoir performance. A second set of factors that need to be considered range from reliability of system, overall complexity, contingency operations, and economics. Instead of a large number of IWS being installed, many questions remain on the performance of these completions. Some of the concerns are lower return than expected/predicted, risk of valve failure affecting well integrity and uncertainty as to the most effective future operational practices. This work reviews several typical intelligent well systems (IWS) completed, including a gas producer, oil producer, auto-gas lift oil producer, multilateral IWS producer, and horizontal openhole multi-isolation producer. For each case, the wellbore modelling, completion design, choking operation strategies, and estimated performance will be introduced. In conclusion, this paper will show how modelling technologies were developed to derive the IWS well and equipment design. It will cover lessons learned through our experience in intelligent well systems, including flow modelling, erosion analysis, tool selection, and crossover control, and how we expect the future movement of this technology to evolve.
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Completion Selection and Design > Completion equipment (1.00)
- Well Completion > Completion Monitoring Systems/Intelligent Wells > Flow control equipment (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (0.94)