Selective Tests in Horizontal Wells for a Better Reservoir Characterization

1993 ◽  
Author(s):  
A.Q. Lara ◽  
Gerard Renard
2021 ◽  
Author(s):  
Hamid Pourpak ◽  
Samuel Taubert ◽  
Marios Theodorakopoulos ◽  
Arnaud Lefebvre-Prudencio ◽  
Chay Pointer ◽  
...  

Abstract The Diyab play is an emerging unconventional play in the Middle East. Up to date, reservoir characterization assessments have proved adequate productivity of the play in the United Arab Emirates (UAE). In this paper, an advanced simulation and modeling workflow is presented, which was applied on selected wells located on an appraisal area, by integrating geological, geomechanical, and hydraulic fracturing data. Results will be used to optimize future well landing points, well spacing and completion designs, allowing to enhance the Stimulated Rock Volume (SRV) and its consequent production. A 3D static model was built, by propagating across the appraisal area, all subsurface static properties from core-calibrated petrophysical and geomechanical logs which originate from vertical pilot wells. In addition, a Discrete Fracture Network (DFN) derived from numerous image logs was imported in the model. Afterwards, completion data from one multi-stage hydraulically fracked horizontal well was integrated into the sector model. Simulations of hydraulic fracturing were performed and the sector model was calibrated to the real hydraulic fracturing data. Different scenarios for the fracture height were tested considering uncertainties related to the fracture barriers. This has allowed for a better understanding of the fracture propagation and SRV creation in the reservoir at the main target. In the last step, production resulting from the SRV was simulated and calibrated to the field data. In the end, the calibrated parameters were applied to the newly drilled nearby horizontal wells in the same area, while they were hydraulically fractured with different completion designs and the simulated SRVs of the new wells were then compared with the one calculated on the previous well. Applying a fully-integrated geology, geomechanics, completion and production workflow has helped us to understand the impact of geology, natural fractures, rock mechanical properties and stress regimes in the SRV geometry for the unconventional Diyab play. This work also highlights the importance of data acquisition, reservoir characterization and of SRV simulation calibration processes. This fully integrated workflow will allow for an optimized completion strategy, well landing and spacing for the future horizontal wells. A fully multi-disciplinary simulation workflow was applied to the Diyab unconventional play in onshore UAE. This workflow illustrated the most important parameters impacting the SRV creation and production in the Diyab formation for he studied area. Multiple simulation scenarios and calibration runs showed how sensitive the SRV can be to different parameters and how well placement and fracture jobs can be possibly improved to enhance the SRV creation and ultimately the production performance.


2016 ◽  
Author(s):  
Budi Abrar ◽  
Zeindra Ernando ◽  
Petronas Carigali ◽  
Ihsan Pasaribu ◽  
Dian Permanasari

2021 ◽  
Author(s):  
Bo Gong ◽  
◽  
Ela Manuel ◽  
Youfang Liu ◽  
David Forand ◽  
...  

Logging-while-drilling (LWD) acoustic imaging technology emerged in the past few years as a low-cost solution to detect and characterize fractures in high-angle and horizontal wells. This type of imaging tool works in either water-based or oil-based drilling fluids, making it a competitive choice for logging unconventional shale wells, which are often drilled with oil-based mud. With high-resolution acoustic amplitude and travel-time images, fractures, bedding planes and other drilling-related features can be identified, providing new insights for reservoir characterization and wellbore geomechanics. The quality of LWD acoustic images however is directly affected by drilling parameters and borehole conditions, as the received signal is sensitive to formation property and wellbore changes at the same time. As a result, interpretation can be quite challenging, and caution needs to be taken to differentiate actual formation property changes from drilling-related features or image artifacts. This paper demonstrates the complexity of interpreting LWD acoustic images through multiple case studies. The examples were collected from vertical and horizontal wells in multiple shale plays in North America, with the images logged and processed by different service companies. Depending on the geology and borehole conditions, various features and artifacts were observed from the images, which can be used as a reference for geologists and petrophysicists. Images acquired with different drilling parameters were compared to show the effect of drilling conditions on image quality. Recommendations and best practices of using this new type of image log are also shared.


1998 ◽  
Vol 1 (03) ◽  
pp. 180-191 ◽  
Author(s):  
I.D. Bryant ◽  
B. Baygun ◽  
M.M. Herron ◽  
A. Matteson ◽  
R. Ramamoorthy ◽  
...  

Abstract The Lower Lagunillas of Bloque IV of the Bachaquero field is a supergiant reservoir that has been in production since 1956. We have carried out a pilot reservoir characterization study in the central part of the field, in which we have integrated all the available data into 3D reservoir simulation models whose purpose is to optimize redevelopment of the area with horizontal wells. An analysis of historical production was undertaken in order to gain an insight into the reservoir dynamics. This analysis indicated the inefficiency of gas injection in providing pressure support to the pilot study area and demonstrated the presence of active aquifer encroachment from the south. Anomalies in production behavior and fluid characteristics indicate both lateral and vertical compartmentalization of the reservoir. We have integrated Fourier Transform Infrared (FTIR) measurements of mineralogy from old cores with a comprehensive logging suite in a new well to re-evaluate older, sparse logging suites. Application of a mineral based log evaluation and high resolution processing of the new logs have led to a significant increase in estimates of oil initially in place in the study area. We have used a novel approach to estimate permeability in all of the study area wells. Combining these new evaluations with a revised geological model enabled us to recognize eleven geological layers throughout the area. Formation pressure measurements confirm that partial barriers to vertical communication exist between most of these layers. Cased hole saturation measurements and historical production data indicate uneven sweep of these layers such that five layers contain bypassed oil that could be recovered by horizontal wells. We have constructed very detailed simulation models that describe the lateral and vertical variation in petrophysical properties of each of these layers. These models have been used to select the optimum locations for horizontal wells and optimize the drilling sequence of these wells and their design. It is estimated that each of these wells could recover 1 to 1.5 million STB within five years. Introduction A pilot reservoir characterization study of the central part of Bloque IV of the Bachaquero field, Venezuela was jointly undertaken by Maraven and Schlumberger with the objectives of increasing both offtake rates and ultimate recovery from this mature field by re-development with strategically located horizontal wells. This paper outlines the way in which old and new data were combined to build predictive reservoir models to guide this strategic infill drilling. The first of the wells recommended by this study was drilled under an integrated service contract in which members of the Maraven and Schlumberger study teams participated in geosteering the horizontal section of the well. The Lower Lagunillas Reservoir The Lower Lagunillas Member constitutes the deepest member of the Miocene age Lagunillas Formation and has an average thickness of some 300 ft in Bloque IV. The reservoirs occur in a faulted synclinal trap between 8,100 ft and 11,400 ft subsea that is bounded to the east by the major Pueblo Viejo Fault and to the west by Fault VLC-70 (Fig. 1). The Lower Lagunillas reservoir of the southwestern part of the Bachaquero field was discovered in 1955. Early estimates suggested that about 2 billion stock-tank barrels (STB) of oil were initially in place in the Lower Lagunillas reservoir of Bloques III and IV. Production commenced from the reservoir in late 1956. Peak production of 215,000 BOPD was achieved in late 1959, from 65 wells (Fig. 2). Gas injection commenced in 1965, after production of 389 MMbbl had already caused significant pressure decline. Oil production in June 1992 was 25,200 BOPD, from 28 producing wells. At this time cumulative recovery was 890 MMbbl [45% of original oil in place (OIIP)], with remaining reserves estimated to be 289 MMbbl (13% of OIIP). Earlier Studies The reservoir has traditionally been subdivided into three units: L, M and N (Fig. 3). In most wells this subdivision was carried out on the basis of recognizing three sand units separated by shales. However, in some wells the M and N Sands are in direct communication.


2016 ◽  
Author(s):  
Budi Abrar ◽  
Zeindra Ernando ◽  
Petronas Carigali ◽  
Ihsan Pasaribu ◽  
Dian Permanasari

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