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Abstract Fracture growth in layered formations with depth-dependent properties has been a topic of interest amongst researchers because of its critical influence on well performance. This paper revisits some of the existing height-growth models and discusses the evaluation process of a new and modified model developed after incorporating additional constraints.The net-pressure is the primary driver behind fracture propagation and the pressure distribution in the fracture plays an important role in vertical propagation, as it supplies the necessary energy for fracture advancement in the presence of opposing forces. The workflow adopted for this study included developing a preliminary model that solves a system of non-linear equations iteratively to arrive at fracture height versus net pressure mapping. The theoretical results were then compared to those available in the literature. The solution set was then extended to a 100-layer model after incorporating additional constraints using superposition techniques.The predicted outcomes were finally compared to the fracture height observations made in the field on several treatments. A reasonable agreement between model-predicted and observed height was observed when a comparison between the two was made, for most cases.The majority of these treatments were pumped in vertical wells, at low injection rates of up to 8.0 bbl/min (0.021 m/s) where net pressures were intentionally restricted to 250 psi (1.72 MPa) in order to prevent fracture rotation to the horizontal plane.The leak-off was minimal given the low permeability formations. In some cases, however, the pumping parameters and fluid imparted pressure distribution appeared to dominate. Overall, it was apparent that for a slowly advancing fracture front, which is the case in low injection rate treatments, the fracture height could be predicted with reasonable accuracy. This condition could also be met in high rate treatments pumped down multiple perforation clusters such as in horizontal wells, though fracture-height measurement may not be as straightforward as in vertical wells. The model developed under the current study is suitable for vertical wells where fracture treatments are pumped at low injection rates. The solid-mechanics solution that is presented here is independent of pumping parameters and can be readily implemented to assist in selection of critical design parameters prior to the job, with a wide range of applicability worldwide.
Gondalia, Ravi Ramniklal (Schlumberger) | Sharma, Amit (Schlumberger) | Shende, Abhishek (Schlumberger) | Jha, Amay Kumar (Schlumberger) | Choudhary, Dinesh (Schlumberger) | Gupta, Vaibhav (Schlumberger) | Shetty, Varun (Schlumberger) | Bordeori, Krishna (Schlumberger) | Barua, Bhaswati Gohain (Schlumberger) | Singh, Mukund Murari (Schlumberger) | Zacharia, Joseph (Schlumberger) | Patil, Jayesh (Joshi Technologies International) | Murthy, P V (Oil and Natural Gas Corporation) | Das, Santanu (Oil and Natural Gas Corporation) | Mahawar, Dheeraj (Oil and Natural Gas Corporation)
Abstract From 2005 to 2020, the application of hydraulic fracturing technology in India has touched the length and breadth of the country in almost every basin and reservoir section. The variety of reservoirs and operating environment present in India governed this evolution over the past 15 years resulting in a different fit for purpose fracturing strategy for each basin varying from conventional single-stage fracturing (urban, desert & remote forested regions) to high volume multi-stage fracturing, deepwater frac-packs and offshore ultra-HPHT fracturing. The objective of this paper is to present the milestones along this evolution journey for hydraulic fracturing treatments in India from 2005 to 2020. This paper begins with a review of published industry literature from 2005 to 2020 categorized by reservoir type and the proven economical techno-operational fracturing strategy adopted during that period. The milestones are covered chronologically since the success or failure of technology application in one basin often influenced the adoption of novel hydraulic fracturing methods in other basins or by other operators during the initial years. The offshore evolution is branched between the west and the east coasts which have distinctly different journeys and challenges. The onshore evolution is split into 5 categories: Cambay onshore Barmer Hills & Tight Gas East India CBM and shale gas Assam-Arakan Basin Onshore KG Basin Each of these regions is at different stages of evolution. The Barmer region is in the most advanced state of evolution with frac factories in place while the Assam-Arakan Basin is in a relatively nascent stage. Figure 1 presents estimated hydraulic stage count based on published literature underlining the exponential growth in hydraulic fracturing activity in India. This paper enlists the technical and operational challenges present in the onshore and offshore categories mentioned above along with the identified novel techno-operational strategies which have proven to be successful for various operators in India. A comparison is presented of the different timelines of the exploration-appraisal-development journey for each region based on the economic viability of fracturing solutions available today in the Industry. Lastly, specific non-technical challenges related to available infrastructure, logistics and social governance are discussed for each region. This paper concludes by identifying the next step-change in the evolution of hydraulic fracturing operations in India among the 5 categories. Each of Government, operators and service providers have important roles to play in expanding the adoption of this technology in India. These roles are discussed for each identified category with the perspective of continuing the country's journey towards energy security.
Selladurai, Jagaan (Petronas Carigali Sdn Bhd) | Roh, Cheol Hwan (Petronas Carigali Sdn Bhd) | Zeidan, Amr (Petronas Carigali Sdn Bhd) | Anand, Saurabh (Petronas Carigali Sdn Bhd) | Madon, Bahrom (Petronas Carigali Sdn Bhd) | Akbar Ali, Anwar Husen (Petronas Carigali Sdn Bhd) | Motaei, Eghbal (Petronas Carigali Sdn Bhd) | Murugesu, Thanapala Singam (Petronas Carigali Sdn Bhd) | Othman, M. Nizar (Petronas Carigali Sdn Bhd) | Ismail, M. Izuddin (Petronas Carigali Sdn Bhd) | Zain, Siti Nur (Petronas Carigali Sdn Bhd) | Zamani, Nur Hidayah (Petronas Carigali Sdn Bhd) | Bela, Sunanda Magna (Petronas Carigali Sdn Bhd)
Abstract Malaysian clastic reservoirs are plagued with high fines content which rapidly deteriorates the productivity from wells completed with conventional form of sand control techniques. To mitigate the fines production issue, Petronas recently successfully completed 3 reservoirs in two wells in Field-D using enhanced gravel pack technique. This paper explains in detail the workflow, challenges such as depleted reservoirs, coal streaks, and nearby water contacts and operational execution for the successful re-defined extension pack jobs. This new approach consists of a re-defined Extension Pack / Frac Pack job with fine movement control resin and a re-defined perforation strategy. Perforation strategy consists of limited number of 180 deg phasing non-oriented perforations done under dynamic underbalance conditions. The key requirement to have fracturing as a sand control method is to have a tip screen out (TSO) or high net pressure placement to ensure the fracture has good conductivity. To obtain a good TSO, data acquisition is of paramount importance. The fracturing jobs in the Field – D wells were preceded with step-rate tests, injection tests, minifrac and Diagnostic Fracture Injection Test (DFIT). The data from diagnostic tests were used diligently to have best possible fracturing treatment in the target zones. Excellent pack factors of greater than 500 lbs. per ft were obtained for all the treatment jobs using only linear gel with proppant concentration up to 7 ppa. This high pack factor translates to very good frac conductivity which is essential in fracturing for sand control. Some of the fracturing treatments concluded with a TSO signature which is a big achievement considering the challenges that were associated with fracturing in Field – D. In addition, DFIT and ACA (After Closure Analysis) was performed to estimate permeability and results were compared with various techniques such as log derived and formation tester permeability. Ultimate objective from this analysis is to have a work-flow which can screen candidate wells for such treatments from openhole logs and give an estimated liquid rate post treatment. Also, the workflow for planning and executing fracturing jobs will be presented for Malaysian clastic reservoirs. This work-flow will be vetted against the extensive diagnostic and fracturing data that has been acquired during fracturing treatments in Field – D. Design, actual diagnostic, and fracturing data will be presented in this paper. It is expected that this modified form of sand and fines control will help in reducing the fines issue in Field – D to a great extent along with expected incremental in oil production. If long term production sustainability is proven, similar approach will be adopted by Petronas and can be shared amongst other South East Asia operators in many similar other fields.
Fu, Jianmin (CNOOC China Limited, Tianjin Branch) | Ma, Yingwen (CNOOC China Limited, Tianjin Branch) | Zhang, Ming (CNOOC China Limited, Tianjin Branch) | Ma, Changliang (CNOOC China Limited, Tianjin Branch) | Liu, Zhengwei (China Oilfield Services Limited) | Zhou, Shubo (Halliburton) | He, Lei (Halliburton) | Feng, Liang (Halliburton)
Abstract The first hydraulic-jet-fracturing multizone completion application was performed in an offshore high-permeability oil well located in the Bozhong oil field in Bohai Bay, China. A detailed case study is presented, highlighting operational challenges and lessons learned from the offshore multizone completion in the Bozhong field. Most offshore high-permeability oilwell completions in the Bozhong field employ tubing conveyed perforation (TCP) followed by frac-packing as multi-zone completions, which is practical in this field. Unlike conventional multizone frac-pack completions, to run perforation guns, the perforating must be completed first, followed by running isolation packers to complete the multizone frac-packing treatments. For hydraulic-jet-fracturing multizone completions, the hydraulic jetting tools are delivered to the target depth using drill pipe; following that, slurry fluid is pumped through the drill pipe to cut through the casing to create fluid flowing channels, which communicate with the pay zone formation. Lastly, the fracturing operation is completed by pumping both proppant slurry through the drill pipe and cleaning fluid through the annulus simultaneously, which creates dynamic hydraulic diversion as functions of isolation between zones. After completing one treatment zone, the tools are pulled to the next target depth, repeating the procedures, until the entire well is complete. After the fracturing treatment, the operator runs production tubing and other accessories, putting the well into production as usual. A detailed completion design and step-by-step operational procedures were prepared based on well data and work conditions to help ensure the effectiveness and safety of the offshore operation. Although some challenges were encountered during the operation, it was overall successfully performed, and significant performance improvement was achieved. After being in production for months, the candidate well has maintained a longer high-production-rate period than the offset wells completed using conventional multizone frac-pack completions. This hydraulic-jet-fracturing multizone completion has proven successful in the Bozhong oil field. The experiences and lessons learned can help benefit future multizone completion optimization for other similar offshore high-permeability oil wells.