Effect of Layered Heterogeneity on Fracture Initiation in Tight Gas Shales

2006 ◽  
Author(s):  
Roberto Suarez-Rivera ◽  
Sidney J. Green ◽  
John McLennan ◽  
Mao Bai
Keyword(s):  
Fracture Initiation ◽  
Tight Gas ◽  
Gas Shales

Integrated Workflow for Selecting Hydraulic Fracture Initiation Points in the Khazzan Giant Tight Gas Field, Sultanate of Oman

2015 ◽  
Author(s):  
David R. Spain ◽  
Raja Naidu ◽  
William Dawson ◽  
German D. Merletti ◽  
Rajeev Kumar ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Initiation ◽  
Tight Gas ◽  
Sultanate Of Oman ◽  
Gas Field

Comparing Friction Reducers' Performance in Produced Water from Tight Gas Shales

2009 ◽  
Vol 61 (11) ◽  
pp. 24-27
Author(s):  
Marcelle L. Ferguson ◽  
Michael A. Johnson
Keyword(s):  
Produced Water ◽  
Tight Gas ◽  
Gas Shales

Connecting the Dots: Multistage Fracturing in Horizontal Wells with Multilayered Reservoirs - Lessons Learned

2022 ◽  
Author(s):  
Ahmed Al Shueili ◽  
Musallam Jaboob ◽  
Hussain Al Salmi
Keyword(s):  
Hydraulic Fracturing ◽  
Learning Curve ◽  
Horizontal Well ◽  
Horizontal Wells ◽  
Fracture Initiation ◽  
Lessons Learned ◽  
Production Performance ◽  
Valuable Insight ◽  
Tight Gas ◽  
Fracture Height

Abstract Efficient multistage hydraulic fracturing in horizontal wells in tight-gas formations with multilayered and laminated reservoirs is a very challenging subject matter; due to formation structure, required well trajectory, and the ability to establish a conductive and permanent connection between all the layers. BP Oman had initiated the technical journey to deliver an effective horizontal well multistage frac design through learnings obtained during three key pilot horizontal wells. Since these initial wells, additional candidates have been drilled and stimulated, resulting in further advancement of the learning curve. Many aspects will be covered in this paper, that will describe how to facilitate the most effective hydraulic fracture placement and production performance, under these laminated conditions. These approaches will include the completion and perforation selection, fracture initiation zone selection, fracture height consideration, frac fluid type and design. The paper will go on to describe a range of different surveillance options, including clean-up and performance surveillance as well as number of other factors. The experiences that have been gained provide valuable insight and learning about how to approach a multistage fracturing horizontal well program in this kind of depositional environment. Additionally, how these lessons can potentially be subsequently adapted and applied to access resources in the more challenging and higher risk areas of the field. For example, this paper will present direct comparison of over and under-displaced stages; differences in execution and production for cased hole and open hole completions; and many other variables that always under discussion for hydraulic fracturing in horizontal wells. This paper describes in detail the results of many multistage fracturing trials by BP Oman in horizontal wells drilled in challenging multilayered and laminated tight-gas reservoirs. These findings may help to cut short learning curve in similar reservoirs in the Middle East Region and elsewhere.

Integration of Post-Fracturing Spectral Noise Log, Temperature Modeling, and Production Log Diagnoses Water Production and Resolves Uncertainties in Openhole Multistage Fracturing

2021 ◽  
Author(s):  
Adnan Bin Asif ◽  
Jon Hansen ◽  
AbdulMuqtadir Khan ◽  
Mohamed Sheshtawy
Keyword(s):  
High Temperature ◽  
Fracture Initiation ◽  
Interval Length ◽  
Valuable Insight ◽  
Flow Profile ◽  
Tight Gas ◽  
Well Completion ◽  
Temperature Modeling ◽  
Integrated Diagnosis ◽  
Array Production

Abstract Hydrocarbon development from tight gas sandstone reservoirs is revolutionizing the current oil and gas market. The most effective development strategy for ultralow- to low-permeability reservoirs involves multistage fracturing. A cemented casing or liner completed with the plug-and-perf method allows nearly full control of fracture initiation depth. In uncemented completions equipped with fracturing sleeves and packers, clearly identifying the fracture initiation points is difficult due to lack of visibility behind the completion and long openhole intervals between packers. Also, the number of fractures initiated in each treatment is uncertain. A lateral was completed with access to 3,190 ft of openhole section across five fracturing stages in a high-temperature and high-pressure tight-gas interval. All stages were successfully stimulated, fracture cleanup flowback was conducted, and entry ports were milled out. A high-definition spectral noise log (SNL) was then conducted along with numerical temperature modeling. Additional logging was done with a set of conventional multiphase sensors. A multi-array production log suite was also performed. Finally, the bottom four stages were isolated with a high-temperature isolation plug based on the integrated diagnosis. The SNL helped to analyze the isolation packer integrity behind the liner. The initiation of multiple fractures was observed, with as many as nine fractures seen in a single-stage interval. A correlation was found between the openhole interval length and the number of fractures. A correlation of fracture gradient (FG) and initiation depths was made for the lateral in a strike-slip fault regime. The fractures were initiated at depths with low calculated FG, confirming the conventional understanding and increasing confidence in rock property calculations from openhole log data. SNL and temperature modeling aided quantitative assessment of flowing fractures and stagewise production behind the liner. Multi-array production logging results quantified the flow and flow profile inside the horizontal liner. The production flow assessments from both techniques were in good agreement. The integration of several datasets was conducted in a single run, which provided a comprehensive understanding of well completion and production. High water producing intervals were isolated. Downstream separator setup after the isolation showed a water cut reduction by 95%. The integration of the post-fracturing logs with the openhole logs and fracturing data is unique. The high-resolution SNL provided valuable insight on fracture initiation points and the integrity of completion packers. Fracturing efficiency, compared to the proppant placed, provides treatment optimization for similar completions in the future.

Leveraging Acoustic Logging for Identification & Quantification of Induced Fractures

2021 ◽  
Author(s):  
Adnan Bin Asif ◽  
Mustafa Alaliwat ◽  
Jon Hansen ◽  
Mohamed Sheshtawy
Keyword(s):  
Fracture Initiation ◽  
Gas Production ◽  
Tight Gas ◽  
Acoustic Logging ◽  
Hydrocarbon Production ◽  
Open Hole ◽  
Cumulative Production ◽  
Sandstone Formation ◽  
Induced Fractures ◽  
Tight Gas Sandstone

Abstract The main objective of the acoustic logging in 15K openhole multistage fracturing completions (OH MSFs) is to identify the fracture initiation points behind pipe and contributing fractures to gas production. The technique will also help to understand the integrity of the OH packers. A well was identified to be a candidate for assessment through such technique. The selected well was one of the early 15K OH MSF completions in the region that was successfully implemented with the goal of hydrocarbon production at sustained commercial rates from a gas formation. The candidate well was drilled horizontally to achieve maximum contact in a tight gas sandstone formation. Similar wells in the region have seen many challenges of formation breakdown due to high formation stresses. The objective of this work is to use the acoustic data to better characterize fracture properties. The deployment of acoustic log technology can provide information of fractures initiation, contribution for the production and the reliability of the isolation packers between the stages. The candidate well was completed with five stages open-hole fracturing completion. As the well is in an open hole environment, a typical PLT survey provides the contribution of individual port in the cumulative production but provides limited or no information of contributing fractures behind the pipe. The technique of acoustic logging helped to determine the fracture initiation points in different stages. If fractures can be characterized more accurately, then flow paths and flow behaviors in the reservoir can be better delineated. The use of acoustic logging has helped to better understand the factors influencing fracture initiation in tight gas sandstone reservoirs; resulting in a better understanding of fractures density and decisions on future openhole length, number of fracturing stages, packers and frac ports placement.

Hydraulic Fracture Initiation and Propagation Model Provides Theoretical Ground for Hybrid-Type Fracturing Schedules in Unconventional Gas Reservoir in the Sultanate of Oman

2015 ◽  
Author(s):  
Andreas Briner ◽  
Alexey Moiseenkov ◽  
Romain Prioul ◽  
Safdar Abbas ◽  
Sergey Nadezhdin ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Initiation ◽  
High Viscosity ◽  
Propagation Model ◽  
Theoretical Ground ◽  
Full Potential ◽  
Tight Gas ◽  
Sultanate Of Oman ◽  
Theoretical Understanding ◽  
The Impact

Abstract A recent series of tight gas discoveries in the Amin formation of the greater Fahud area represents some of the most exciting exploration success of this decade in the Sultanate of Oman. The structures have been evaluated as containing very significant amounts of gas locked in a challenging deep and hot environment requiring hydraulic fracture stimulation. Since their discoveries, the two primary challenges have been difficult breakdown of the formation and limited proppant placement during stimulation attempts. The early experience in the exploration and appraisal campaigns from 2009 to 2014 has led to fracture designs with conservative proppant amounts that could limit the full potential of the field. Several geomechanical studies have been commissioned in the past to guide completion strategies in well placement, perforation, and fracture stimulation design. The objectives of this study were to model hydraulic fracture initiation and breakdown in the three Amin zones (upper, middle, and lower) to provide some theoretical understanding of the impact of the different parameters on the observed field breakdown pressures. In agreement with field observations, the model showed that lowering the viscosity of the pad has a major impact in lowering the breakdown pressures. Consequently, current best practices include formation breakdown and hydraulic fracture propagation with low-viscosity fluids followed by proppant placement with high-viscosity fluids. When applied to tight gas formations in the Sultanate of Oman, the hybrid fracturing evolves from conventional designs for the purpose of successful fracture initiation, while still placing a successful job.

scholarly journals Constraining tectonic components during a geomechanics-aided successful hydrofracturing campaign of tight gas exploration field

2021 ◽  
Author(s):  
Rajeev Ranjan Kumar ◽  
Menno Mathieu Molenaar ◽  
Surej Kumar Subbiah
Keyword(s):  
Tensile Strength ◽  
Fracture Initiation ◽  
Horizontal Stress ◽  
Fracture Analysis ◽  
Wellbore Stability ◽  
Stress Profile ◽  
Strain Component ◽  
Tight Gas ◽  
Horizontal Strain ◽  
Regional Tectonics

AbstractThe horizontal stress profile plays an important role, extending from wellbore stability analysis to well completion optimization of tight gas reservoirs. When considering exploration fields with planned wells being drilled to 5500-m TVD, it is imperative to quantify tectonic effects at the well location. In addition, accurately predicting stress profile and fracture initiation values in vertical wells is required to identify sweet zones and barriers. This paper presents the details of a pre-fracture geomechanical model using breakouts and advanced acoustic data for post-fracture analysis. The analysis contains a history match of fracture initiation pressure, which consider the effects of filter cake around permeable sand, variation in tensile strength, and quantification of horizontal stress contrast in the different fields. Overall, three reservoirs have been analyzed, each containing more than eight wells with operations history. Core tests were used to calibrate dynamic-to-static rock elastic and mechanical properties, both of which reduced uncertainty in the model. The poroelastic horizontal strain method was used to build a continuous stress profile. Typically, the rock fabric found in the cores, images, and anisotropy data from the three reservoirs is different and required various dynamic-to static conversions. The Aeolian deposits-based reservoir has a wide variation in horizontal stress, and fracture height is typically governed by the stiffness of the layers. The lower permeability zones have relatively higher tensile strength, compared with higher permeability zones leading to relatively higher fracture initiation values. Overall, the ratio of maximum horizontal stress-to-minimum horizontal stress varies between 1.20 and 1.28 based on post-fracture analysis, which correlates well with regional tectonics and structural data. Depending on lithological variation and structure changes, the horizontal strain component varies at the layer level within regional tectonics. Inversion of fracturing data helped to constrain horizontal strain and stress variations in the field.

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