Impact of Wellbore Completion Type on Fracture Initiation Pressure in Maximum Tensile Stress Criterion Model for Tight Gas Field in the Sultanate of Oman

Briner, Andreas; Florez, Juan Chavez; Nadezhdin, Sergey; Gurmen, Nihat; Alekseenko, O. P.; Cherny, S. G.; Kuranakov, Dmitry; Lapin, Vasily

doi:10.2523/iptc-18261-ms

Cited by 10 publications

(1 citation statement)

References 8 publications

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“…The overall trend of the breakdown pressure is consistent with the results of numerical simulation studies [37][38][39][40]. The ideal perforation orientation angle is zero, corresponding to the minimum breakdown pressure [41]. Therefore, the larger the perforation angle, i.e., the greater the angle between the perforation axis and the maximum horizontal principal stress, the more energy needs to be consumed to counteract the increasing stress and the more difficult it is to crack.…”

Section: Effect Of Acidizingsupporting

confidence: 86%

A New Experimental Method for Acid Pretreatment in Perforated Horizontal Wells: A Case Study of Mahu Conglomerate Reservoir

Jia,

Mou,

Wang

et al. 2023

Processes

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The Mahu Oilfield in Xinjiang, China, is the world’s largest conglomerate oilfield, with a daily output of more than 8000 tons. In the fracturing of perforated horizontal wells, the breakdown pressure is high, resulting in difficulties in their treatment. Acid pretreatment has been applied to reduce the breakdown pressure in the field, but with poor performance. Few studies have been conducted on how acid pretreatment affects the breakdown pressure under perforation conditions in the Mahu conglomerate reservoir. Also, existing fracturing or acid pretreatment experiments cannot simulate perforation well. Therefore, a new method was developed to make perforations by hydro jetting the fracturing specimens (300 mm × 300 mm × 300 mm) first. It can achieve specified perforation parameters, including the perforation angle, position, and length. Subsequently, true triaxial hydraulic fracturing experiments were conducted on the conglomerate specimens obtained from the Mahu area. The effects of the acid pretreatment on the fracture initiation and breakdown pressure were investigated by injecting the perforation section of the conglomerate using various acid systems. The study results showed that the perforation made by the new apparatus was extremely close to the perforation on-site. The acid pretreatment effectively dissolved minerals and could decrease the breakdown pressure down to 7.7 MPa. A combination of 6%HF + 10%HCl was recommended for the acid pretreatment in the Mahu conglomerate reservoir. A total of 60 min acid–rock contact time is necessary for sufficient rock dissolution. The mechanism of the acid pretreatment to decrease the breakdown pressure is that the rock dissolution by the acid reduces the rock tensile strength and increases the permeability. The raised permeability increases the fluid pressure of the reservoir near the wellbore so as to reduce the breakdown pressure of the formation. The research results provide technical support for reducing construction difficulty and optimizing parameters in the Mahu Oilfield.

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Section: Effect Of Acidizingsupporting

confidence: 86%

A New Experimental Method for Acid Pretreatment in Perforated Horizontal Wells: A Case Study of Mahu Conglomerate Reservoir

Jia,

Mou,

Wang

et al. 2023

Processes

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Accelerated Learning Curve Through Industry Collaboration: Case Studies from Large Tight Gas Project Executed in an International Marketplace

Riyami¹,

Briner²,

Nadezhdin

et al. 2016

Day 1 Mon, November 07, 2016

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A large, strategically important tight gas project in the Sultanate of Oman progressed over 5 years on an accelerated path from exploration to the development stage. Collaboration between operator and service provider helped advance the deployment of technology that made this acceleration possible. Poor initial success in both hydraulic fracturing treatment placement and hydrocarbon productivity along with limited resources with ever-expanding work scope were the main challenges faced in the first 2 years of exploration. To address these challenges, an integrated approach to the project was taken. Technology trials and the selective deployment of technology along with improved operations gave flexibility to this new efficiency model. Close collaboration with the service provider allowed smoother and faster progress. Collaboration included joint technology mapping exercises, team visits to North American locations of the operator and the service provider with the goal of knowledge sharing, faster technology transfer, and the secondment of a senior engineer from the service provider as a full-time production technologist to the operators' subsurface team. The effective execution of strategy and implementation of various technologies resulted in an increase in the success rate of fracture placement and zonal evaluation from the initially low 50% to 100%. The integration of several disciplines was critical to achieving this goal. Technologies deployed in the project comprised of rock and core mechanical tests, such as reservoir coring, openhole stress testing, sonic measurements, continuous unconfined compressive strength measurements, abrasive perforating, various fracturing treatment designs, and several geomechanical studies targeting different aspects of fracture initiation. An additional focus was on the assessment of fracture geometry using radioactive tracers, advanced sonic logging, geomechanical evaluation coupled with geological mapping, microseismic monitoring, and cutting-edge fracture design methodology in both vertical and horizontal wells. The collaborative efforts led to evaluation of similarities and differences between North American and international unconventional projects and suggested techniques and best practices that can be applied in the tight gas project in the Sultanate of Oman. This project has been deemed one of the first commercially successful gas deliveries in the Middle East from a tight gas reservoir. Technologies, methods, and strategies developed for this large tight gas project and tested in the field will contribute to improving the success rate on similar projects around the world.

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Horizontal Wells Hydraulic Fracturing from Tight HPHT to Multilayer Differential Depleted Gas Accumulations in Oman

Juan¹,

Mohamed²,

Alawi³

et al. 2017

Day 2 Tue, November 14, 2017

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The development of Oman gas accumulations requires the use of hydraulic fractures as part of the sand face completion, multi fractured horizontal wells were identified as potential well architecture that allow effective hydrocarbon recovery while reducing the number of well. The unique geological properties of the reservoirs require different fracture strategies and technology deployment to make them commercially viable. Fracturing High Pressure High Temperature (HPHT) as well as Multilayer Differential Depleted (MDD) formations takes the implementation of this technology to its limits; the challenges are further increased by stress regime variations due to tectonics and rock properties heterogeneities encounter across the horizontal section, challenging the effective placement of transverse fractures, fracture conductivity and final hydrocarbon gas deliverability. It is well agreed the multivariable nature of this challenges, however these are not well understood. A holistic approach was used starting with the fractured vertical wells in both challenging environments (HPHT & MDD) this providing the stepping stone for the definition of the fracture implementation strategies in horizontal wells. It was possible to identify three key areas influencing the fracture implementation, these covering design, monitoring and diagnostics; from this three areas, fracture diagnostics was a vital stage on fracturing optimization, on this stage the use of pressure and rate data, radioactive tracers, microsismic monitoring were used to provide information about fracture propagation behavior, geometry and containment; on the other hand, production logging and well test data were used to assess fracture conductivity and inflow performance. The combination of calibrated fracture and inflow simulation platforms were essential for the analysis of the considerable amount of data generated as part of the diagnostic stage. However, commercial available analytical and numerical inflow tools provide limited options to incorporate details variations of fracture conductivity, effective fracture length and inertial affects across the fracture plane. This paper will describe the developed methodology used for fracturing horizontal wells that combines extensive data acquisition and evaluation in combination with the development of in-house software platforms with commercially available tools and how it was incorporated the detail results from calibrated fracture simulation and characterization with inflow analytical and numerical models, this to estimate the inflow performance across the fractured interval and the subsequent generation of inflow profiles (Synthetic Production Logs). It will be also discussed the comparison of the estimated inflow profiles with measured inflow from production logging (PLT). Finally it will be presented how through the use of the developed methodology was possible to optimize completion, perforation, fracturing and production strategies critical aspects for field development.

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Impact of Wellbore Completion Type on Fracture Initiation Pressure in Maximum Tensile Stress Criterion Model for Tight Gas Field in the Sultanate of Oman

Cited by 10 publications

References 8 publications

A New Experimental Method for Acid Pretreatment in Perforated Horizontal Wells: A Case Study of Mahu Conglomerate Reservoir

A New Experimental Method for Acid Pretreatment in Perforated Horizontal Wells: A Case Study of Mahu Conglomerate Reservoir

Accelerated Learning Curve Through Industry Collaboration: Case Studies from Large Tight Gas Project Executed in an International Marketplace

Horizontal Wells Hydraulic Fracturing from Tight HPHT to Multilayer Differential Depleted Gas Accumulations in Oman

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