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Collaborating Authors
Tight gas
Abstract These are exciting times for unconventional resource development across North America. This success has proven to be a driver for the rest of the world to attempt to emulate the game-changing results found in the industry. As a consequence, improved horizontal drilling and hydraulic completion technology are currently being disseminated to the rest of the world, where operators are seeking to replicate the North American success in tight reservoirs and shale plays of interest. This being further fueled by higher gas prices than are awarded in North America. This paper introduces a work-flow process to describe how tight gas-sand potential was discovered in the Mezardere Formation in the southern part of the in Thrace Basin in NW Turkey. The process began with the development of an improved understanding of geology and reservoir characterization followed by the application of North American drilling and completion technologies to commercially extract hydrocarbons from previously uneconomic resources. Design of hydraulic fracturing, including pad volumes, proppant and gel concentrations, stage volumes and typical pressure profiles, production profiles and well design parameters are established. The content also presents how completion designs can be improved in a vertical well application in existing wellbores as a means to mitigate capital risk in a horizontal development plan. The paper concludes by showing how the successful extraction of commercial gas production from heretofore uneconomic portions of the Thrace basin has the potential to change the energy future in Turkey via dramatically improved production results over previous conventional completions. When results were made public, the basin garnered attention from many large E&P Operators. The results proved that improved economic enhancement of deep basin unconventional resources as possible; thereby changing and accelerating development plans for this type of play.
- North America > United States (1.00)
- Asia > Middle East > Turkey (1.00)
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.48)
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying (0.93)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Maverick Basin > Eagle Ford Shale Formation (0.99)
- Asia > Middle East > Turkey > Thrace Basin (0.99)
3D Enhanced Subsurface Data Visualization and Integration for Effective Horizontal Well Multi Transverse Fracture Development on a Clastic Tight Gas Field in Oman
Al-Suleimani, Ahmed Abdullah (Petroleum Development Oman) | Chavez, Juan Carlos (Petroleum Development Oman) | Abbass, Hazim (Haliburton) | Smaoui, Radouan (FracGeo) | Abassi, Ahmed (FracGeo) | El Hamal, Bachir (FracGeo) | Bachir, Aissa (FracGeo) | Poludasu, Srichand (FracGeo) | Yi, Mi Chin (FracGeo) | Attia, Bilel (FracGeo) | Ouenes, Ahmed (FracGeo)
Abstract Horizontal wells with multiple transverse fractures were defined as the key well architecture and completion strategy oriented to develop clastic tight gas accumulation otherwise impossible to be developed with vertical wells. However, a detailed evaluation during early deployment indicates the need for an integrated subsurface platform (ISP) covering geophysics, geology and geomechanics, to support well placement, well orientation and hydraulic fractured design. Detailed subsurface characterization was used to build the ISP. Geomechanical logs estimated using the drilling data, as wells as, wireline logs are used to define engineered completion strategies. The ISP provide us with three dimensional properties maps capturing lithogical, petrophysical and geomechanical properties distribution, this allow the identification of the properties anisotropy coveing key variables including, elastic properties, in-situ stress variation, stress rotation across the field and stress anisotropy, thecombination of the predicted stimulated reservoir volume and the dynamic model, both part of the ISP, were used to access potential production forecast for selected well locations. The ISP support the identification of geological sweet spot to definelanding zones and optimizing the hydraulic fracturing to improve the production performance. We will discuss how the geomechanical evaluation provides us the spatially varying stress magnitude and stress orientation and strain across the tight reservoir units. The use of the geological and geomechanical data within the ISP can be used to estimate geomechanical half lengths that are used to improve fracture design. We will also discuss how completion optimization and number of perforation clusters can be defined to maximize gas production based on a better understading of the special variation of petrophysical, geomechanical and lithological properties across reservoir units. The described integrated subsurface platform can be used to help optimize horizontal well placement, well orientation and fracture completion design. It will be discussed the procedures and process of integration geophysical, geological and geomechanical reservoir properties into the ISP, as well as, how this was used to support the continuous development of these tight gas accumulation in Oman.
- Asia > Middle East > Oman (0.71)
- North America > United States > Texas (0.46)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.85)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (0.87)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (31 more...)
Deployment Strategies for Effective Hydraulic Fracturing Vertical, Highly Deviated and Horizontal Wells Across Challenging Differential Depleted Tight Gas Formations in Oman
Chavez Florez, Jua Carlos (PDO) | Fathy Abdelazim, Mohamed (PDO) | Bahri, Khalfan (PDO) | Al-Yaqoubi, Mazin (PDO) | Abri, Ahmed (PDO) | Hinai, Adnan (PDO)
Oman tight gas accumulation has been initially developed with fractured vertical wells targeting up to 10 different hydrocarbon units, as well as with dedicated highly deviated to horizontal wells targeting the most tighter zones. The intrinsic geomechanical, petrophysical and lithological heterogeneities of this tight units impact not only the fracture conductivity distribution but the drainage efficiency of the fractured zones, this is observed as mobility variations across this unit impact their contributions once all become commingle, with the areas of higher mobility dominating the total gas well production, this for all wells architectures. This paper will discuss fundamental formation characterization requirements to assess in-situ stress dynamic variations during the life of the field; incorporating formation pressure points as integral part of the drilling program and in-situ stress measurements supported by comprehensive mini-fracture data evaluation. The use of radioactive tracers in combination with production logging were implemented to assess containment and fracture prediction, providing this an essential tool to determine fracture propagation behavior, deployment strategy and final conductivity distribution. It will be described the logging requirements as well as the lab characterization needed to determine key elastic properties to assess the hydraulic requirements for fracturing individual units or combination of them. It will be discussed how variations on pore pressure and stress profiles, as the field developed, will impact perforation and fracture strategies for vertical, highly deviated and horizontal wells. It will be presented how increase of pressure confinement affects the in-situ elastic properties as depletion is experienced on specific gas units, inducing alterations on stress and net pressure profiles that impact fracture propagation and final conductivity distribution, this becomes of particular importance on highly deviated and horizontal wells where vertical connectivity with all hydrocarbon units is fundamental to maximize recovery. Finally, it will discuss the methodology used for fracture deployment considering the differential depletion expected during the field development and its impact on completion integrity and fracture implementation strategies. We will share the identified best practice that will lead to optimum fracture development while maximize investment. 2 SPE-200073-MS
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.94)
- Asia > Middle East > Oman > Al Wusta Governorate > Hazar Field (0.99)
- Asia > Middle East > Oman > Al Wusta Governorate > Ghaba Salt Basin > Mabrouk Field > Gharif Formation (0.99)
- Asia > Middle East > Oman > Bashair Sandstone Formation (0.98)
- (2 more...)
Enhancement of Production Data in Tight Gas Reservoir Through an Automated Multiphase Measurement Skid for Remote Operation
Garay Andrade, Carlos (ENAP) | Sanz Vera, Julio (ENAP) | Salas, Fabian (ENAP) | Pucci, Claudio (Schlumberger) | Castro, Alejandro (Schlumberger) | Bastos, Vlamir (Schlumberger) | Schubert, Ewaldo (Schlumberger) | Theuveny, Bertrand (Schlumberger)
Abstract A novel implementation of an economical, self-sustainable and environmentally friendly solution for tight gas field production monitoring in a remote location in Tierra Del Fuego, allows early-stage production measurements necessary in the unconventional reservoir analysis for the field recovery process optimization. This innovative solution is based on the development of a portable skid designed for production test measurement in a multi-well pad, that combine a multiport selector valve and a multiphase flow meter, making possible to remotely select a well to measure and transfer flow data in real time. The commands for the well selection and the data transmission can be done via satellite with an encrypted software directly from the Operator's office. A PhotoVoltaic (PV) solar panel was developed to provide a reliable self-sufficient power for the entire system from 100% clean energy. Located in Chile's Tierra del Fuego region, the Magallanes Basin comprises two main structural regions: a normal faulted eastern region and a thrust faulted western area. These remote tight gas fields undergoing rapid decline are big challenges to explore, develop and produce economically. They demand a close initial surveillance through timely production tests to acquire representative data, which allows consolidation of a reservoir analysis and development methodologies to optimize ultimate and cost-effective recovery. An innovated approach was successful implemented for production monitoring using the Multiphase Measurement Skid, which provided the required data quality and frequency along with flexibility to perform production test in multiple wells, all remotely controlled from the Operator's office. The entire system is self-sufficient and powered by solar panels designed, which brings sustainability avoiding the use of generator and dealing with fuel logistics making this solution environmentally friendly carbon-free emission. Such sustainable and self-sufficient solution to monitor single to multiple wells (up to eight), combines an automated multiport valve system with multiphase measurement technology for remote operations. Its operation is simple and efficient, amd it provides a continuous data stream of well test information to the production and reservoir engineers managing the field.
- South America > Chile (0.87)
- South America > Argentina > Tierra del Fuego Province (0.75)
- North America > United States > Texas (0.46)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Tight gas (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Downhole and wellsite flow metering (1.00)
- (2 more...)
- Information Technology > Data Science (0.67)
- Information Technology > Communications > Networks (0.66)
- Information Technology > Architecture > Real Time Systems (0.54)
Machine Learning Empowered Well Placement in a Large Unconventional Tight Gas Field in China
Yu, Ting (Schlumberger) | Wang, Xiangzeng (Shaanxi Yanchang Petroleum Group Co., Ltd.) | Carrillat, Alexis (Schlumberger) | Du, Kuifu (Schlumberger) | Liang, Quansheng (Research Institute of Shaanxi Yanchang Petroleum Group Co., Ltd.) | Grossmann, Tino (Schlumberger) | Zhu, Ming (Schlumberger) | Wang, Gaige (Schlumberger) | Feng, Lijun (Schlumberger Copower Oilfield Engineering Co., Ltd.) | Xue, Jie (Schlumberger Copower Oilfield Engineering Co., Ltd.) | Quan, Min (Schlumberger Copower Oilfield Engineering Co., Ltd.) | Saraiya, Rasesh Krishnaraj
Abstract An undisclosed tight-gas field produces gas from a large heterogenous fluvial reservoir with limited well control in margins and appraisal areas, as well as sparse advanced logs (formation micro-imaging, magnetic resonance, or sonic tools, etc). The principal goal of this study is to provide a novel solution using machine-learning (ML) techniques to predict sandstone distribution and to some extent automate the process of optimizing well placement. This workflow overcomes low data quality, scaling, and inconsistency, and builds the bridge between geoscience and artificial intelligence (AI) software platforms. This newly proposed solution provides a combination of ML and geological studies to optimize well placement. The key steps of this technology are: Use unsupervised seismic waveform classification together with well logs to define sand body distribution and generate a reservoir risk map to support well planning. Construct a 3D grid with multiple variables to extract and integrate well logs and seismic attributes from existing 2D seismic lines for data organization and analysis. Set up the data transform mechanism to unlock restrictions of data analysis between subsurface domain and AI software platforms. Test multiple ML algorithms by carrying out a deep search to find seismic attributes that are the most sensitive to reservoir parameters and form the decision trees for quantitative analysis. Evaluate and select the high-performance results, export them into the subsurface software platform, and make the final property model available for integration and visualization to support well placement. Multiple tests have been completed to date in this gas field, and the results showed that the technique can improve well placement, add potential reserve and also improve the efficiency of the workflow by reducing the execution time by 240 times. The results provide solid support to achieve more reliable and accurate well placement. This new solution generates an improved reservoir risk map with flexibility of using many secondary variables or their combinations. It produces results with higher resolution and focuses on improving efficiency. It also reduces turnaround time and increases collaboration over conventional approaches by improving the accuracy of fast predictions as the data flow enriches the database rapidly, which unleashes big data potential. This innovative solution can be applied to other projects especially ML empowered well placements in complex geological settings.
- Overview > Innovation (0.69)
- Research Report > New Finding (0.49)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.70)
- Geophysics > Seismic Surveying > Seismic Interpretation (0.55)
- Asia > China > Shanxi > Ordos Basin (0.99)
- Asia > China > Shaanxi > Ordos Basin (0.99)
- Asia > China > Gansu > Ordos Basin (0.99)
- North America > United States > Louisiana > China Field (0.97)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Tight gas (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Data Science & Engineering Analytics > Information Management and Systems > Artificial intelligence (1.00)
Seismic estimation of fluid saturation based on rock physics: A case study of the tight-gas sandstone reservoirs in the Ordos Basin
Li, Chao (Hohai University) | Hu, Peng (Hohai University) | Ba, Jing (Hohai University) | Carcione, Josรฉ M. (Hohai University, National Institute of Oceanography and Applied Geophysics (OGS)) | Hu, Tianwen (CNPC) | Pang, Mengqiang (Hohai University)
Abstract Tight-gas sandstone reservoirs of the Ordos Basin in China are characterized by high rock-fragment content, dissimilar pore types, and a random distribution of fluids, leading to strong local heterogeneity. We model the seismic properties of these sandstones with the double-double porosity theory, which considers water saturation, porosity, and the frame characteristics. A generalized seismic wavelet is used to fit the real wavelet, and the peak frequency-shift method is combined with the generalized S-transform to estimate attenuation. Then, we establish rock-physics templates (RPTs) based on P-wave attenuation and impedance. We use the log data and related seismic traces to calibrate the RPTs and generate a 3D volume of rock-physics attributes for the quantitative prediction of saturation and porosity. The predicted values are in good agreement with the actual gas production reports, indicating that the method can be effectively applied to heterogeneous tight-gas sandstone reservoirs.
- Asia > China > Shanxi Province (0.61)
- Asia > China > Shaanxi Province (0.61)
- Asia > China > Gansu Province (0.61)
- Asia > India > Andhra Pradesh > Bay of Bengal > Krishna-Godavari Basin (0.99)
- Asia > China > Shanxi > Ordos Basin (0.99)
- Asia > China > Shaanxi > Ordos Basin (0.99)
- (28 more...)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Tight gas (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Abstract Due to a resource optimization and efficiency improvements, wells that are hydraulically fractured in the tight gas Barik Formation of the Khazzan Field in the Sultanate of Oman are often temporarily left shut-in directly following a large scale massive hydraulic fracturing stimulation treatment. Extensive industry literature has often suggested (and reported), that this may result in a significant direct loss of productivity due to the delayed flowback and the resulting fracture conductivity and formation damage. This paper will review the available data from the Khazzan Field address these concerns; indicating where the concerns should and should not necessarily apply. The Barik Formation in the Khazzan Field is an over-pressured gas-condensate reservoir at 4,500 m with gas permeability ranging from 0.1 to 20 mD. The average well after hydraulic fracturing produces 25 MMscfd and 500 bcpd against a wellhead pressure of 4,000 psi. A typical hydraulic fracturing stimulation treatment consists of 14,000 bbl of a borate-crosslinked guar fluid, placing upwards of 1MM Lbs of high conductivity bauxite proppant within a single fracture. In order to assess the potential production loss due to delayed flowback operations, BP Oman performed a suite of formation damage tests including core samples from the Barik reservoir, fracture conductivity considerations and dynamic behaviors. Additionally, normalized production was compared between offset wells that were cleaned-up and put onto production at different times after the hydraulic fracturing operations. Core tests showed a range of fracture conductivities over time with delayed flowback after using the breaker concentrations from actual treatments. As expected, enhanced conductivity was achieved with additional breaker. The magnitude of the conductivity being created in these massive treatments was also demonstrated to be dominant with respect to damage effects. Finally, a normalized comparison of an extensive suite of wells clearly showed no discernible loss of production resulted from any delay in the flowback operations. This paper describes in details the workflow and resulting analysis of the impact of extensive shut-in versus immediate flowback post massive hydraulic fracturing. It indicates that the impact of such events will be limited if the appropriate steps have been taken to minimize the opportunity for damage to occur. Whereas the existing fracturing literature takes the safe stance of indicating that damage will always result from such shut-ins, this paper will demonstrate the limitations of such assumptions and the flexibility that can be demonstrated with real data.
- Research Report > New Finding (0.46)
- Research Report > Experimental Study (0.46)
- Geology > Mineral > Silicate > Phyllosilicate (0.46)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.30)
From Technical Evolution to Production Performance: A Technical Review of 700 Wells Over 8 Years in the South Sulige Tight Gas Field
Wang, Dong (PetroChina Changqing Oil Company) | Dong, Yifan (PetroChina Changqing Oil Company) | Yang, Shengfang (PetroChina Changqing Oil Company) | Rignol, Joel (TOTAL E&P Chine) | Wang, Qiang (TOTAL E&P Chine) | Liu, Yuan (Schlumberger) | Liu, Yaolan (Schlumberger) | Zhao, Liang (Schlumberger) | Wang, Weikan (Schlumberger) | Loh, Pengpeng (Schlumberger) | Enkababian, Philippe (Schlumberger)
Abstract Unlike many unconventional resources that demonstrate a high level of heterogeneity, conventional tight gas formations often perform consistently according to reservoir quality and the applied completion technology. Technical review over a long period may reveal the proper correlation between reservoir quality, completion technology, and well performance. For many parts of the world where conventional tight gas resources still dominate, the learnings from a review can be adapted to improve the performance of reservoirs with similar features. South Sulige Operating Company (SSOC), a joint venture between PetroChina and Total, has been operating in the Ordos basin for tight gas since 2011. The reservoir is known to have low porosity, low permeability, and low reservoir pressure, and requires multistage completion and fracturing to achieve economic production. Over the last 8 years, there has been a clear technical evolution in South Sulige field, as a better understanding of the reservoir, improvement of the completion deployment, optimized fracturing design, and upgraded flowback strategy have led to the continuous improvement of results in this field. Pad drilling of deviated boreholes, multistage completions with sliding sleeve systems, hybrid gel-fracturing, and immediate flowback practices, gradually proved to be the most effective way to deliver the reservoir's potential. Using the absolute open-flow (AOF) during testing phase for comparative assessment from South Sulige field, we can see that in 2012 this number was 126 thousand std m/d in 2012, and by 2018 this number had increased to 304 thousand std m/d, representing a 143% incremental increase. Thus, technical evolution has been proved to bring production improvement over time. Currently, South Sulige field not only outperforms offset blocks but also remains the top performer among the fields in the Ordos basin. The drilling and completion practices from SSOC may be well suited to similar reservoirs and fields in the future.
- North America > Canada > British Columbia > Western Canada Sedimentary Basin > Alberta Basin > Deep Basin (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Deep Basin (0.99)
- Asia > China > Shanxi > Ordos Basin > Changqing Field (0.99)
- (10 more...)
Abstract An accurate Mechanical Earth Model (MEM) is of vital importance in tight gas reservoirs where hydraulic fracturing is the only way to produce hydrocarbons economically. The Barik tight gas reservoir is the main target in Khazzan and Ghazeer Fields at the Sultanate of Oman (Rylance et al., 2011). This reservoir consists of multiple low-permeability sandstone layers interbedded with marine shales. A good understanding of the fracture propagation in such a reservoir has a major effect on completion and fracturing design. The MEM derived from sonic logs and calibrated with core data needs to be further validated by independent measurements of the fracturing geometry. Multiple surveillance techniques have been implemented in the Barik reservoir to validate the MEM and to match observations from hydraulic fracturing operations. These techniques include closure interpretation using a wireline deployed formation testing assembly, the use of mini-frac injection tests with deployed bottomhole pressure gauges, execution of post injection time-lapse temperature logging, the injection of radioactive tracers, associated production logging, subsequent pressure transient analysis and other techniques. A cross-disciplinary team worked with multiple sources of data to calibrate the MEM with the purpose of delivering a high-confidence prediction of the created fracture geometry, which honors all available surveillance data. In turn, this validation approach provided a solid basis for optimization of the completion and fracturing design, in order to optimally exploit this challenging reservoir and maximize the economic returns being delivered. For example, combination of stress testing with radioactive tracers provided confidence in stress barriers in this multilayered reservoir. Pressure transient analysis allowed to calibrate mechanical model to match fracturing half-length that is contributing to production. This paper provides extensive surveillance examples and workflows for data analysis. Surveillance of this degree in the same well is uncommon because of the associated time and cost. However, it provides unique value for understanding the target reservoir. This paper demonstrates the Value Of Information (VOI) that can be associated with such surveillance and provides a concrete and practical example that can be used for the justification of future surveillance programs associated with the hydraulic fracturing operations.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.56)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.50)
- Asia > Middle East > Oman > Central Oman > Barik Formation (0.99)
- Asia > Middle East > Oman > Al Wusta Governorate > Arabian Basin > Rub' al-Khali Basin > Barik Field > Barik Formation (0.97)
- Asia > Middle East > Oman > Ad Dhahirah Governorate > Arabian Basin > Rub' al-Khali Basin > Block 61 EPSA > Block 61 > Ghazeer Field > Miqrat Formation (0.95)
- (16 more...)
Abstract Unconventional and tight gas reservoirs are located in deep and competent formations, which requires massive fracturing activities to extract hydrocarbons. Some of the persisting challenges faced by operators are either canceled or non-productive fractures. Both challenges force oil companies to drill new substitutional wells, which will increase the development cost of such reservoirs. A novel fracturing method was developed based on thermochemical pressure pulse. Reactive material of exothermic components are used to generate in-situ pressure pulse, which is sufficient to create fractures. The reaction can vary from low pressure pulse, to a very high loading up to 20,000 psi, with short pressurization time. In this study, Finite Element Modeling (FEM) was used to investigate the impact of the generated pressure-pulse load, by chemical reaction, on the number of induced fractures and fracture length. Actual tests of pulsed fracturing conducted in lab scale using several block samples compared with modeling work. There was a great relationship between the pressure load and fracturing behavior. The greater the pulse load and pressurization rate, the greater the number of created fractures, and the longer the induced fractures. The developed novel fracturing method will increase stimulated reservoir volume of unconventional gas without introducing a lot of water to formation. Moreover, the new method can reduce formation breakdown pressure by around 70%, which will minimize number of canceled fracturing.
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Tight gas (1.00)