Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
The deep high pressure/high temperature (HPHT) dolomite formation in Northern Kuwait has been a challenge with varied production, attributable to reservoir heterogeneity. Due to the tight nature of these rocks, matrix acidizing may not produce desired effects, thus requiring hydraulic fracturing to produce at economic rates. However, the tectonic setting in high stress environment has resulted in subpar success and inconsistent results from stimulation treatments in matrix and hydraulic fracturing applications. This paper presents a multidisciplinary approach to address the limited success in the Northern Kuwait Dolomites. An integrated petrophysical evaluation of the current wells will be followed with multi-well Heterogeneous Rock Analysis (HRA), to evaluate the reservoir heterogeneity across the field and identify the ‘sweet spots’ for future drilling locations. Evaluation and lessons learnt from the past stimulation treatments, will be used to understand geo-mechanical challenges and to help calibrate the Mechanical Earth Model (MEM) for implementation in the future wells. Finally, using a reservoir-centric stimulation design tool, stimulation type (acid fracturing vs proppant fracturing) and stimulation design optimization for future wells will be developed. A reservoir-level petrophysical evaluation of the existing wells was performed and compared to understand the reservoir heterogeneity vis. a vis. production potential. Multiple rock classes were identified within the tight dolomite interval, with a gross thickness of ~250 ft. Starting with log based MEM, results from the image log interpretation and the field observations/measurements from fracture diagnostic tests (Decline analysis, Calibration injection) were used in calibrating the MEM and mapping the Completion Quality (CQ) heterogeneity across the field. This has led to a reservoir-level understanding, which can enable planning optimal well locations, target interval and subsequent well placement/completions methodology. Finally, using the reservoir-centric design tool, an optimum design to effectively stimulate the ultralow-permeability dolomites was determined. The optimization workflow did not only include a single-faceted approach of fracture modeling, but also encompassed a production forecast using the integrated numerical reservoir simulator. Lessons learnt from the optimization workflow were further extended to designing horizontal wells (landing point, trajectory for optimal stimulation geometry), and hence to aid in field development strategy. Using the multidisciplinary unconventional workflow, the heterogeneity in reservoir quality and completion quality was evaluated, both along the wellbore and spatially. In essence, we found that natural fractures along with high Critical Net Pay (CNP) allows you to vertically connect with good RQ and thus, is required for success in these tight reservoirs. Following which, reservoir-centric stimulation design tool enabled optimization of completion and stimulation design in a holistic approach, to maximize appraisal and production opportunities.
The deep high pressure/high temperature (HPHT) dolomite formation in Northern Kuwait has been a challenge with varied production, attributable to reservoir heterogeneity. Due to the tight nature of these rocks, matrix acidizing may not produce desired effects, thus requiring hydraulic fracturing to produce at economic rates. However, the tectonic setting in high stress environment has resulted in subpar success and inconsistent results from stimulation treatments in matrix and hydraulic fracturing applications. This paper presents a multidisciplinary approach to address the limited success in the Northern Kuwait Dolomites. An integrated petrophysical evaluation of the current wells will be followed with multi-well Heterogeneous Rock Analysis (HRA), to evaluate the reservoir heterogeneity across the field and identify the ‘sweet spots’ for future drilling locations. Evaluation and lessons learnt from the past stimulation treatments, will be used to understand geo-mechanical challenges and to help calibrate the Mechanical Earth Model (MEM) for implementation in the future wells. Finally, using a reservoir-centric stimulation design tool, stimulation type (acid fracturing vs proppant fracturing) and stimulation design optimization for future wells will be developed. A reservoir-level petrophysical evaluation of the existing wells was performed and compared to understand the reservoir heterogeneity vis. a vis. production potential. Multiple rock classes were identified within the tight dolomite interval, with a gross thickness of ~250 ft. Starting with log based MEM, results from the image log interpretation and the field observations/measurements from fracture diagnostic tests (Decline analysis, Calibration injection) were used in calibrating the MEM and mapping the Completion Quality (CQ) heterogeneity across the field. This has led to a reservoir-level understanding, which can enable planning optimal well locations, target interval and subsequent well placement/completions methodology. Finally, using the reservoir-centric design tool, an optimum design to effectively stimulate the ultralow-permeability dolomites was determined. The optimization workflow did not only include a single-faceted approach of fracture modeling, but also encompassed a production forecast using the integrated numerical reservoir simulator. Lessons learnt from the optimization workflow were further extended to designing horizontal wells (landing point, trajectory for optimal stimulation geometry), and hence to aid in field development strategy. Using the multidisciplinary unconventional workflow, the heterogeneity in reservoir quality and completion quality was evaluated, both along the wellbore and spatially. In essence, we found that natural fractures along with high Critical Net Pay (CNP) allows you to vertically connect with good RQ and thus, is required for success in these tight reservoirs. Following which, reservoir-centric stimulation design tool enabled optimization of completion and stimulation design in a holistic approach, to maximize appraisal and production opportunities.
Jurassic's kerogen shale-carbonate reservoir in North Kuwait is categorized as a source rock exhibiting micro- to Nano Darcy permeability and is Kuwait Oil Company's focus in recent years. Although the challenges are significant (formation creep, fracturing initiation, etc.), the efforts toward producing from unconventional reservoirs and applying experience from both USA and Canada in this field are ongoing. As a step toward development, the gas field development group selected a vertical pilot well to measure the inflow of hydrocarbon from a single fracture while minimizing formation creep (flowing of particulate material and formation into the wellbore that blocks the production). This step was required prior to drilling a long horizontal lateral wells and completing it with multiple hydraulic fractures to confirm commercial production. A comprehensive design process was executed with the full integration of operator and service company competencies to achieve the three main objectives: First, characterize the kerogen rock mechanics which allows selection of the most competent kerogen beds to prevent collapse of the hole during fracturing (creep effect) by conducting scratch, unconfined stress, proppant embedment, and fluid compatibility tests. Then, prepare a suit of strength measurements on full core samples to help in fracturing design and minimize creep effect. The second objective was to design and implement a robust proppant fracturing program that avoids the kerogen concerns after selecting the most competent reservoir unit and suitable proppant type. Third, perform controlled flowback to unload the well and attempt to establish clean inflow unlike previous attempts that failed to either suitably stimulate or prevent solids production (deliver clean inflow). After analyzing the lab test results, choosing the optimal fracturing design, and preparing the vertical well for proppant hydraulic fracturing, the treatment was performed. In December 2019, the hydraulic fracturing treatment with resin-coated bauxite proppant was successfully pumped through 6 ft of perforation interval and followed by a controlled flowback. Resin-coated bauxite proppant was specifically selected to overcome the creep and embedment effects during the fracture closure and flowback. Moreover, a properly designed choke schedule was implemented to balance unloading with a delicate enough drawdown to avoid formation failure. This paper discusses in detail the lab testing, evolution of fracturing design, treatment analysis, and the robust workflow that led to successfully achieving all main objectives, paving the way for long horizontal lateral wells. This unconventional undertaking in Kuwait presents a real challenge. It is a departure from traditional methods, yet it points toward a high upside potential should the appraisal campaign be completed effectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.