Yassin, Mohamed A. (Geosciences Department, CPG, KFUPM, Dhahran Saudi Arabia) | Abdullatif, Osman M. (Geosciences Department, CPG, KFUPM, Dhahran Saudi Arabia) | Makkawi, Mohammad H. (Geosciences Department, CPG, KFUPM, Dhahran Saudi Arabia) | Yousif, Ibrahim M. (Geosciences Department, CPG, KFUPM, Dhahran Saudi Arabia) | Osman, Mutasim S. (Geosciences Department, CPG, KFUPM, Dhahran Saudi Arabia)
Well exposed Jurassic outcrops belt in central Saudi Arabia provides good outcrop analogs which can be utilized to capture the high resolution facies types and architecture that might help to fill the inter-wells gap in the subsurface. This study is focused on the characterization and modeling the facies types, body geometries deposited in geomorphic elements of carbonate ramp system and the distribution of the reservoir properties on it. Three-dimensional models for the different facies-body geometries were conducted to provide accurate stochastic representation. This study was conducted at a selected Jurassic outcrop reservoir analog that exposed around Riyadh area. The Mesozoic carbonate strata of central Saudi Arabia are interpreted to have been deposited in ramp systems and exposed in hundreds of kilometers in the strike and dip direction of palaeoshoreline. The study integrates detailed sedimentological and stratigraphic analysis from outcrop strata to capture facies-body geometries and their petrophysical properties on the ramp system. Nine lithofacies were interpreted from the stratigraphic sections. Spatially, the porosity and permeability show different ranges of heterogeneity from micro to meso and macro scales. Laterally, the reservoir properties show steady variations in contrast with the abrupt change vertically. This variation seems to be related to the sedimentary structure, grain size, and degree of cementation. Different pore types were recognized in the studied intervals, which include fracture, intraparticle, moldic and intercrystalline porosities. Several 3D facies models were constructed using sedimentological and stratigraphic data that collected from the field. These models express the complex and heterogeneous relationship between facies-body geometries in the outcrop precisely. Integration of these data to subsurface equivalent reservoirs will provide qualitative and quantitative information useful for understanding and predicting reservoir quality and architecture in carbonate ramps.
Roth, Brian A. (SAUDI ARAMCO) | Xiao, Jinjiang J. (SAUDI ARAMCO) | Abdelaziz, Mohannad (Baker Hughes) | Mack, John (Baker Hughes) | Sarawaq, Yahya (Baker Hughes) | Reid, Richard (GE Oil and Gas Vetco Gray Inc) | Helvenston, Andrew
Electric submersible pumps (ESPs) are a widely used artificial-lift technology. Conventional ESP systems provide power with a cable banded to the outside of the tubing. These systems have drawbacks in terms of installation speed and efficiency. To overcome these obstacles, a novel cable-deployed (CD) ESP system developed for use in a production environment with high hydrogen sulfide (H2S) content is presented as a future solution. This paper focuses on the challenges, results, and lessons learned from the first field deployment in the world of a rigless high-H2S CD-ESP system.
A metal-jacketed power cable was a key enabler to the CD-ESP system. The metal-jacketed power cable delivers the best protection for an H2S attack and provides a smooth outside diameter that could be gripped on and sealed. The cable had been tested to withstand H2S levels up to 15% in the vapor phase and chloride levels in excess of 150,000 ppm, with an expected service life in excess of 10 years, derived from laboratory testing.
To overcome well-control concerns, a vertical cable-hanger spool (VCHS) was developed to enable the ESP cable to be terminated below the master valve. In addition to the surface termination of the cable, the VCHS provided hang-off and production-flowthrough capabilities.
The CD-ESP system, using a specialized inverted ESP, required close integration between several equipment and service providers during the development of equipment and procedures to ensure success in the installation of the system. The system’s initial deployment was in a benign onshore well that offered ample workspace for the various service providers to learn the unique aspects of this rigless deployment. The interface between the service providers at the surface-cable termination was critical to the successful installation. For this trial test, the well completion was changed from 41/2-in. tubing to 7-in. tubing to accommodate the CD 562 Series ESP.
Lessons learned from this field trial will be incorporated into future trials of the technology. The goal of these future trials will be to deploy the technology in offshore H2S wells where high rig costs can be significantly reduced by using a lower-cost barge coupled with increased speed, efficiency, and ease of CD-ESP deployment.
Periere, Matthieu Deville de (Badley Ashton and Associates Ltd.) | Foote, Alexander (Badley Ashton and Associates Ltd.) | Bertouche, Meriem (Badley Ashton and Associates Ltd.) | Shah, Razza (Al Hosn Gas.) | al-Darmaki, Fatima (Al Hosn Gas.) | Ishaq, Wala bin (Al Hosn Gas.)
The Lower Arab D Member (Kimmeridgian) in onshore UAE is typically characterised by a thick succession of homogeneous mudstones with local cm-scale interbedded bivalve-rich floatstones, which are thought to have been deposited in a low-energy mid-ramp setting. This sedimentological unit is located at the base of a sour gas reservoir that includes the oolitic grainstones of the Upper Arab D Member. The pore system in these micritic deposits is dominated by matrix-hosted microporosity, along with open to partially cemented fractures, primary intraparticle macropores and rare biomoulds in the shell beds, hence a poor to very good porosity and extremely poor to rarely excellent permeability. Variations in porosity and permeability values appear to be strongly related to variations in the micritic fabric: both porosity and permeability increase when the micritic fabric evolves from anhedral compact with coalescent intercrystalline contacts (associated with very little and poorly connected micropores) to subrounded with facial to subpunctic intercrystalline contacts (with locally well-developed micropores). Micritic fabrics also clearly impact the elastic properties of the rock. Through analysis of elastic moduli calculated from standard density, and shear/compressional sonic wireline logs, the relationship between micritic fabric, porosity, permeability and geomechanical properties has been explored.
Kohda, Atsuro (INPEX Corporation) | Bellah, Sameer (ZADCO) | Shibasaki, Toshiaki (ZADCO) | Farhan, Zahra Al (ZADCO) | Shibayama, Akira (INPEX Corporation) | Hamami, Mohamed Al (ZADCO) | Jasmi, Sami Al (ZADCO)
The understanding of heterogeneous rock properties especially high-permeability streaks is very important to predict fluid behavior in carbonate reservoirs. An Upper Jurassic reservoir in "Field A" has been producing for 30 years with different production scheme such as crestal water and gas injection at the different stage. The observed water/gas breakthrough and the evolution trend in water cut/GOR indicate reservoir heterogeneity caused by geological complexity. To replicate such complicated fluids behavior in reservoir model, the characterization study for high-permeability streaks was conducted.
Multiple data sources were used to identify and characterize high-permeability streaks.
Interpreted injected gas/water sweep intervals utilizing cased-hole production logging. Identified potential high-permeable lithofacies and its stratigraphic positions by detailed core and thin section descriptions with petrophysical observations. Defined high-permeability streaks based on the integrated interpretation of multiple data sources. Characterized the high-permeability streaks in reservoir model with excess flow capacity estimated from model and well-test permeability.
Interpreted injected gas/water sweep intervals utilizing cased-hole production logging.
Identified potential high-permeable lithofacies and its stratigraphic positions by detailed core and thin section descriptions with petrophysical observations.
Defined high-permeability streaks based on the integrated interpretation of multiple data sources.
Characterized the high-permeability streaks in reservoir model with excess flow capacity estimated from model and well-test permeability.
This study revealed that multiple types of high-permeability streaks present in the reservoir. In particular, it was recognized that a specific thin layer comprises stromatoporoid (epibenthic calcified sponges) patch reef deposits acts as the main contributor for fluids movement. This paper shows how to characterize the high-permeability streaks in reservoir model focusing on stromatoporoid lithofacies.
Thickness of stromatoporoid lithofacies shows heterogeneous variation of 0 to 14 feet. The complex pore system in stromatoporoid lithofacies associated with heterogeneously distributed skeletal fragments with centimeter-scale makes difficulty for capturing accurate permeability from conventional plug measurement. The plug permeability was generally underestimated comparing with actual flow capacity estimated from well-test. Hence the modeled permeability which generated from porosity-permeability correlation coming from plug measurement was required further conditioning based on the pre-established concept for high-permeability streaks.
To fill the gap between modelled and well-test permeability-thickness (KH) i.e. excess KH, the relevance between excess KH and stromatoporoid lithofacies was investigated. As a result, it was found that the zonal well-test KH increases as stromatoporoid lithofacies thickness (STR-H) increases, and there is a good correlation between STR-H and STR-KH estimated as "zonal well-test KH" minus "zonal modeled KH except stromatoporoid lithofacies intervals". Therefore, excess KH was allocated to only into the part of stromatoporoid lithofacies. The prepared STR-H map was directory transformed to STR-KH distributions by the revealed correlation. Through dynamic history matching, permeability distribution was iteratively modified by updating STR-H map in concordance with depositional concept.
Detailed observations and integrated interpretation for multiple data sources allowed identifying high-permeability streaks and establishment of a model workflow for representing its heterogeneity and associated permeability distribution. This workflow enabled geologically reasonable permeability conditioning and iterative model update in conjunction with the depositional concept during dynamic history matching.
Al-Shammari, Fowzi (Saudi Aramco) | Al-Thiyabi, Adel (Saudi Aramco) | Rifat, Said (Saudi Aramco) | Rafee, Majed (Saudi Aramco) | Ahmed, Danish (Schlumberger) | Al Hamwi, Kaisar (Schlumberger) | Arifin, Muhamad (Schlumberger)
Throughout the history of the oil and gas industry, numerous developments have been made, especially in the drilling sector. In Saudi Arabia, wells that historically have been drilled and completed vertically and deviated have been completely shifted to horizontal and even past that to extended reach and multilateral wells. Horizontal wells have enhanced the possibility of draining relatively thin formation layers, maximizing reservoir contact, decreased water and gas coning, increased exposure to natural fracture systems in the formation and better sweep efficiencies. On other side, drilling a horizontal well and further drilling a lateral adds the complexity with respect to lateral accessibility, especially during the workover and well intervention services.
Considering the challenges associated with drilling multilateral wells, completion and well intervention, an innovative completion was installed for the first time ever in an oil well in Saudi Arabia. The innovative completion technique introduced the idea of a pseudo-multilateral where the other laterals are not actually drilled but the completion consists of needles that extend into the formation enabling the well to have more reservoir contact.
The innovative pseudo-lateral completion was installed during a workover operation in an oil well in Saudi Arabia for the first time, whereas, the well was completed as an open hole in a tight formation with an electrical submersible pump (ESP) initially. Prior to installation of the innovative pseudo-multilateral completion, the well was facing issues to sustain production and though the well was stimulated using coiled tubing (CT), the intervention did not meet the objectives. Therefore, after the installation of an innovative pseudo-multilateral completion, followed by a stimulation intervention, the well was able to produce at a stabilized production rate.
To evaluate completion effectiveness of this pseudo-multilateral technology, the multispinner production logging via CT was conducted to determine which pseudo-laterals were contributing to the inflow. Since this is the first production log in this type of completion, the logging bottom-hole assembly and procedures were modified to overcome the challenges, such as completion internal geometry and profile. The production logging was executed successfully and the multispinner production logging analysis shows a homogenous production profile. The logging result provided the input in optimizing the pseudo-multilateral completion and increasing the confidence to pursue this technology in other applications.
This paper will present the process in designing, executing and evaluating the first production logging in the pseudo-multilateral completion. It will examine benefits and challenges of running production logging in such a completion. In addition, it will display advantages and disadvantages of installing a pseudo-multilateral completion as evident from well testing through the production logging.
Manifa is one of the largest engineering projects in the world, involving causeways, bridges, drilling islands, offshore platforms, and onshore drill sites. The field's output reached 500,000 BOPD of crude from a network of wells drilled through man-made islands.
Our industry has embarked largely on implementing the intelligent field initiative in recent years, which is a clear indication of the surge to adapt to new methods, processes and workflows to manage existing and new fields. The capacity at which this technology was implemented worldwide is a sign of a strong buy-in from the industry that this technology will deliver on its promises in terms of maximizing hydrocarbon production, recovery, profits, or health, safety and environmental compliance.
Saudi Aramco is considered to be a leader in deploying and utilizing the intelligent field technology to maximize the value of hydrocarbon reservoirs. This paper discusses the implementation of intelligent field initiative in Saudi Arabian fields and particularly in the world's largest intelligent field, the Khurais complex. It highlights the huge infrastructure to measure and transmit data and to manage and control production in this field. As a result of the lessons learned from this experience, the classical reservoir management concepts are going through a major transformation to adapt to a fundamental change in data acquisition and production controls. Moreover, the engineers were faced with a new challenge in the reservoir monitoring process and overall field optimization, which requires a paradigm shift in analysis, interpretation, and decision making to maximize the value of the intelligent field. So far, the industry's efforts to utilize intelligent field technology are mainly focused at well level to optimize production rate and ensure target rate compliance. Saudi Aramco's efforts are going beyond the well level to optimize reservoir performance and enhance oil recovery. This paper illustrates some of those efforts, which resulted in a better understanding of well deliverability and reservoir connectivity.
In addition, this paper highlights the major challenges facing operating companies, to manage those fields. It provides methods and workflows to mitigate these challenges and maximize the value of intelligent fields and fully utilize the existing infrastructure and capabilities.
Introduction: Real-Time Reservoir Management
The first section of this paper deals with the definition of real-time reservoir management, which is essential to set the stage for discussing the value of intelligent fields. The benefits realized from intelligent field technology are highly correlated to the success of implementing real-time reservoir management. This section starts with a general definition of reservoir management, which is followed by a discussion on the evolution of the reservoir management process and the introduction of real-time reservoir management. Finally, it highlights Saudi Aramco's efforts to build four major layers to ensure successful implementation of real-time reservoir management.
Two phases in the evolution of drilling operations centers are identified on the basis of published information. The first was examined in detail in an earlier paper (Booth 2009). The second is examined here by way of a review of several operators' strategies over time and in different areas of operation. The first generation of centers was short-lived, failing to survive the reductions in oil price and drilling activities of the late 1980s. The second generation, beginning in the early 2000s, benefited from rapid evolution of information technology in the intervening years and is part of a broader trend toward integrated operations and collaborative work processes. Common trends are identified from the case histories presented. These include a discussion of foundational capability, data and architecture standards, higher-level work processes, and organizational-change management.
With the focus on continuous drilling optimization, a collaborative effort was implemented to analyze and assess drilling challenges encountered while drilling extended horizontal wells in the Khurais field in Saudi Arabia. The primary requirement was to enhance the efficiency of conventional downhole motor directional drilling systems in the challenging horizontal reservoir section.
The Khurais field is located in a remote area in the central part of Saudi Arabia approximately 200 km from the Saudi capital Riyadh, and 300 km from the Eastern port city of Dammam. The producer wells are drilled in the middle of the field and the water injector wells are drilled close to the field boundaries.
An average of 12 rigs worked simultaneously throughout the duration of the project to drill and complete the required increment wells. The horizontal wells are comprised of the producers, trilateral producers and power water injectors. The wells were drilled to an averaged measured depth of 14,000 ft, with an average of 6,500 ft of open hole section across the reservoir. The 6??? horizontal hole section is particularly challenging and is drilled with steerable mud motors with the assistance of real time geosteering and logging while drilling (LWD) tools to maintain the horizontal open hole section of the well close to the top of the reservoir within a window of 3 ft.
The fracture intervals coupled with high permeability makes the drilling of this section particularly challenging, as mud losses are frequently encountered in this section. The main difficulties to improve the efficiency of the directional drilling process were high drag and differential sticking.
To overcome the challenges mentioned above, the drilling team utilized a new sliding technology that interacts with the drilling rig top drive to break the static friction improving the weight transfer to the bit, and thereby increase the rate of penetration (ROP). Through the virtual elimination of differential sticking and reduction of buckling problems, this system smoothly helps to deliver weight down to the bit. Additional benefits of this innovative technology are the prevention of stalling of the mud-motor, steady orientation of tool face and easier steering.
The authors will describe the innovative system utilized to improve the ROP during the sliding process by almost 50% and will present real cases supported by field data. They will also illustrate the importance of post-actions review and rig crew training in the achievement of record ROP in sliding mode. Historical cases will be presented and the benefits of the application of this technology in these wells will be explained.
This paper reviewed the management of injection water quality in a super-giant carbonate oil field operated by ADCO onshore Abu Dhabi since 1973. This field was subjected to peripheral water flooding in order to maintain reservoir pressure and provide a mechanism to sweep the oil. Injected water was sourced from 23 water supply wells completed into deep hyper-saline aquifers with total suspended solids (TSS) of 1.5 mg per liter (mg/l). Each water supply was connected to a cluster of 4-5 water injectors. Clusters were interconnected.
Produced water having average TSS of 100 mg/l and oil in water (OIW) content of 260 parts per million (ppm) was being reinjected into the most permeable reservoir through five well peripheral pilots injector. No significant operational problem was reported apart from occasional injectivity degradation which was restored with a maximum of one acid stimulation per well since 2002. New facilities under construction were designed for a maximum OIW of 100 ppm with plans being made to reduce it to 50 ppm as the volume of produced water was expected to rise with the field wide implementation of gas lift.
After more than 30 years of production from two major high-quality reservoirs, ADCO recently started the development of a third oil-bearing Reservoir X classified as low permeability. Accepted assumptions based on the extensive water injection experience proved questionable considering the low median pore size diameter of the reservoir under development. The common water supply for the peripheral water injectors assigned to the three different oil-bearing reservoir zones posed an additional challenge as the water injectors drilled in the low permeability reservoir needed to be shielded from temporary degradation of water quality typically experienced during start-up operations after maintenance or water supply well workover.
The issue of temporary high solid loading gained importance as the practice of discharging water loaded with solids to a pit was discontinued after 1998 for environmental reasons. Several studies related to water quality were recently performed including the onsite cycling of aquifer water through reservoir core plugs of Reservoir X in order to predict the potential degradation in matrix injectivity over time and evaluate the resulting operational cost and timing of future acid stimulations. Material selection for the surface pipeline network carrying the aquifer water was also reviewed with non-metallic internals being recommended. In the event of a temporary degradation of water quality following system start-up or a workover in a water supply well, disposal of such water into the source aquifer was determined to be the best solution to avoid injecting water loaded with solids in the low permeability reservoir, also fulfilling all regulatory requirements.