The Application of Unstructured Gridding Techniques for Full Field Simulation of a Giant Carbonate Reservoir Developed with Long Horizontal Wells

Author(s):  
Helle Vestergaard ◽  
Henrik Olsen ◽  
Ali Shahbaz Sikandar ◽  
Ismail A. Abdulla ◽  
Rashed Noman
2008 ◽  
Vol 11 (06) ◽  
pp. 958-967 ◽  
Author(s):  
Helle Vestergaard ◽  
Henrik Olsen ◽  
Ali S. Sikandar ◽  
Ismail A. Abdulla ◽  
Rashed Noman

2022 ◽  
Author(s):  
Ahmed Elsayed Hegazy ◽  
Mohammed Rashdi

Abstract Pressure transient analysis (PTA) has been used as one of the important reservoir surveillance tools for tight condensate-rich gas fields in Sultanate of Oman. The main objectives of PTA in those fields were to define the dynamic permeability of such tight formations, to define actual total Skin factors for such heavily fractured wells, and to assess impairment due to condensate banking around wellbores. After long production, more objectives became also necessary like assessing impairment due to poor clean-up of fractures placed in depleted layers, assessing newly proposed Massive fracturing strategy, assessing well-design and fracture strategies of newly drilled Horizontal wells, targeting the un-depleted tight layers, and impairment due to halite scaling. Therefore, the main objective of this paper is to address all the above complications to improve well and reservoir modeling for better development planning. In order to realize most of the above objectives, about 21 PTA acquisitions have been done in one of the mature gas fields in Oman, developed by more than 200 fractured wells, and on production for 25 years. In this study, an extensive PTA revision was done to address main issues of this field. Most of the actual fracture dynamic parameters (i.e. frac half-length, frac width, frac conductivity, etc.) have been estimated and compared with designed parameters. In addition, overall wells fracturing responses have been defined, categorized into strong and weak frac performances, proposing suitable interpretation and modeling workflow for each case. In this study, more reasonable permeability values have been estimated for individual layers, improving the dynamic modeling significantly. In addition, it is found that late hook-up of fractured wells leads to very poor fractures clean out in pressure-depleted layers, causing the weak frac performance. In addition, the actual frac parameters (i.e. frac-half-length) found to be much lower than designed/expected before implementation. This helped to improve well and fracturing design and implementation for next vertical and horizontal wells, improving their performances. All the observed PTA responses (fracturing, condensate-banking, Halite-scaling, wells interference) have been matched and proved using sophisticated single and sector numerical simulation models, which have been incorporated into full-field models, causing significant improvements in field production forecasts and field development planning (FDP).


2007 ◽  
Vol 10 (05) ◽  
pp. 453-457 ◽  
Author(s):  
Rajesh Kumar ◽  
S. Ramanan ◽  
J.L. Narasimham

Summary Oil productivity from Mumbai High field, an offshore multilayered carbonate reservoir, increased significantly through the implementation of a major redevelopment program. Geoscientific information available from approximately 700 exploratory and develop- ment wells drilled in the field during nearly 25 years was incorporated during geological and reservoir simulation modeling of the field. High-technology drilling (viz. horizontal/multilaterals for the new development wells) was adopted on field scale to effectively address typical complexity of the layered carbonate reservoirs. Since the commencement of the project in 2000, approximately 140 new wells were drilled, mostly with horizontal and multilateral drainholes. Besides these, more than 70 suboptimal producers were also converted as horizontal sidetracks under brownfield development. The horizontal sidetracks were drilled as long-drift sidetrack (LDST), extended-reach drilling (ERD), LDST-ERD, short-drift sidetrack (SDST), and medium-radius drainhole (MRDH) types of wells through the application of innovative and emerging drilling technologies with nondamaging drilling fluids, whipstocks to kick off sidetrack wells, rotary-steering systems, and expandable tubulars to complete horizontal sidetracks in lower layers. With the implementation of this project, the declining trend was fully arrested and a significant upward trend in production has been established. Introduction The field redevelopment process requires the intergration of reservoir-development strategies, facility options, and drilling and production philosophies to maximize oil and gas recovery from a matured field. A significant number of case studies are available on mature field revitalization using a multidisciplinary team concept, exhaustive geo-scientific data analysis, and new drilling technologies (Chedid and Colmenares 2002; Clark et al. 2000; Dollens et al. 1999; Kinchen et al. 2001). Advancements in drilling and completion technology have enabled construction of horizontal wells with longer wellbores, more-complex well geometry, and sophisticated completion designs. Horizontal wells provide an effective method to produce bypassed oil from matured fields. In the early 1980s, this technology was in the development stage and was used in limited applications. By the 1990s, the technology had matured, and its acceptance in the industry had increased significantly. Performance of horizontal/multilateral wells, risk assessment of horizontal-well productivity and comparison of horizontal- and vertical-well performance in different fields is available in literature (Babu and Aziz 1989; Brekke and Thompson 1996; Economides et al. 1989; Joshi 1987; Joshi and Ding 1995; Mukherjee and Economides 1991; Norris et al. 1991; Vij et al. 1998). A significant number of horizontal/multilateral development wells were drilled as a part of redevelopment of Mumbai High, a matured multilayered carbonate offshore field in Western India. The details of new technologies applied and performance of these new high-technology wells are presented in this paper. Besides comparison of well productivity of horizontal and conventional sidetrack wells, this paper presents some technical issues faced.


1991 ◽  
Author(s):  
G.R. King ◽  
D.E. Snyder ◽  
T.S. Obut ◽  
R.L. Perkins
Keyword(s):  

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