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Gryaznov, Andrey (Baker Hughes Reservoir Technical Services) | Wiprut, David (Baker Hughes Reservoir Technical Services) | Basu, Pramit (Baker Hughes Reservoir Technical Services) | Jafarov, Tural (Baker Hughes Reservoir Technical Services) | Reese, Michael (Baker Hughes Reservoir Technical Services) | Vossen, Johannes (Baker Hughes Reservoir Technical Services)
Abstract The objectives of this study were to deliver a pre-drill and real-time (RT) geomechanical model and wellbore stability analysis for the planned horizontal well within license Block XIb, Republic of Georgia. The main target is fractured tight volcanoclastic Middle Eocene (ME) formation. Pre-drill and RT Wellbore stability analyses were performed enabling safe mud weight requirements and mud weight sensitivity to inclination for the planned wellbore, as this area is significantly understudied in terms of rock properties, pore pressure behaviour and geomechanics. The model study was based on the drilling experience of the offset well, drilled a mile away and containing many data sets: wireline logs and borehole images, FIT/LOT, pressure measurements, drilling experience and cuttings, well construction and from the current well containing basic LWD gamma ray and mud log. The main problem areas were defined based on the model. Pore pressure drove many of the observed challenges, including the Maikop overpressured shales forming significant breakout zones, and the overpressured Upper Eocene sand and reactive Navtlugi shales zone experiencing many tight hole events in the offset well. Pore Pressure was later updated for the current well based on the drilling exponent (Dxc) calibrated with mud gas data as a part of RT Geomechanics study. The natural fracture behaviour of ME was carefully studied to identify potentially critically stressed fractures and near-wellbore fracture slip. The models examined breakout during underbalanced drilling as well as optimal well azimuths to minimize potential fluid losses in open fractures during drilling and avoid water cut during production. The study found that the originally planned mud weight was too risky and has to be increased in the overburden formations to avoid massive breakouts, as experienced in the offset well. While crossing target ME fractured volcanoclastic slightly underbalanced drilling may be possible. The pre-drill fracture stability study successfully confirmed its reliability during operations and allowed confidently make RT decisions. As a result, concern for losses lowered while moving the azimuth from Shmin to SHmax direction and mud weight (MW) could be raised confidently up to required level. The conducted studies, despite many challenges and data uncertainties, significantly clarified potential drilling risks within the license block area, which was understudied in terms of geomechanics in past years. Additional value was provided to future drilling programs as well as highlighting data gaps and pathways for further geomechanical model improvement and uncertainty mitigation. The model is the first valuable step in developing regional geomechanical understanding. Increased MW helped to avoid major tight hole events, detailed natural fractures analysis helped to select wellbore azimuth optimal to avoid fluid losses. As a result, rate of penetration (ROP) increased 2.3 times compared to previously drilled wells and the well became the first in the field history drilled with no fluid and cement losses. Pre-drill geomechanical model helped to develop the program suitable for safe drilling and later its success was proven through RT geomechanics support. RT geomechanical model update together with caving analysis demonstrated how it plays key role together with pre-drill geomechanical modelling in the successfully well delivery.
Nearly 30 years ago as the Soviet Union lay in tatters, Azerbaijan and Kazakhstan signed off on the Caspian's first oil and gas megaprojects, hoping to guarantee their independence by transforming the region's energy landscape and their role in it. Nursultan Nazarbayev, then president of Kazakhstan, took the first step in April 1993 by creating Tengizchevroil (TCO), a joint venture between Chevron and Kazakh state oil company KazMunaiGaz, to develop the super-giant Tengiz oil field and nearby Korolev field. Today, Chevron still holds 50% of the venture, ExxonMobil controls 25%, KazMunaiGaz, 20%, and LukArco, a subsidiary of Russia's Lukoil, 5%. A year and a half later, in September 1994, Azerbaijan's president, the late Heydar Aliyev, signed a production-sharing agreement (PSA) to develop the deepwater reserves of the Azeri, Chirag, and Gunashli (ACG) fields, attracting the participation of a "who's who" of the world's oil and gas elit 13 global companies representing eight countries. These and other signings had a knock-on effect as more upstream megaprojects popped up across the region in the late 1990s and throughout the early 2000s, attracting more international participation and the need to develop midstream infrastructure such as Azerbaijan's Baku‑Tbilisi-Ceyhan pipeline (BTC) export line to Turkey and Kazakhstan's Caspian Pipeline Consortium (CPC) to Russia's oil export terminal at Novorossiysk, as landlocked Central Asia devised ways to get its crude oil to market.
BP has signed a deal with a joint venture between Petrofac and SOCAR, the Azeri state oil company, to support its osshore and onshore operations in the Caspian Sea. These include the offshore Azeri-Chirag-Gunashli and Shah Deniz fields, along with the associated Baku-Tbilisi-Ceyhan pipeline, the South Caucasus pipeline, and the Western Route export pipeline.
Abstract Fractures are common features of many carbonate reservoirs. Given complex flow network that they create, characterization of dynamic behavior of these reservoirs is often complicated and becomes important, especially, if fractures provide primary pathways of fluid flow. In this paper a novel semianalytical simulator was used to understand the pressure behavior of naturally fractured reservoir containing a network of discrete and/or connected finite and infinite-conductivity fractures. In this study an integrated interpretation methodology is applied to analyze well test data acquired in open hole section of exploration well drilled into highly fractured carbonate reservoir of Lower Eocene - Upper Cretaceous sediments on Patardzeuli field of Block XI-B, Republic of Georgia. The main steps consisted of explicitly modeling fractures - both wellbore-intersecting fractures and fractures located away from wellbore - using formation microimager data and calibrating the model to actual well test response using a unique novel mesh-free semi-analytical simulator designed for fractured reservoirs. Study presents the results of well test of one zone performed in highly fractured carbonate reservoir drilled in Patardzeuli field. The pressure-transient response confirmed the complexity of reservoir and dominant contribution to flow regimes from fractures. It is shown in this paper that there are many factors that dominate transient behavior of a well intersected by natural fractures, such as fracture conductivity, length, intensity and distribution, as well as whether fractures intersect the wellbore or not. Moreover, it was demonstrated that presence or absence of damage on wellbore-intersecting fractures in vicinity of wellbore will impact the pressure- transient behavior of reservoir and shape overall productivity of the well. The novelty of the approach is the analysis of the dynamic behavior using a unique semi-analytical pressure transient simulator for fractured reservoirs. The simulator can be used to obtain a response for arbitrarily distributed infinite and/or finite conductivity natural fractures within the reservoir by modeling them explicitly. In this study, it allowed to maximize the value of well tests by assessing the effect of fractures on reservoir dynamic behavior and obtain matrix and fracture parameters where conventional well test interpretation tools would be deemed unviable.
Abstract Fractures are common features of many carbonate reservoirs. Given complex flow network that they create, characterization of dynamic behavior of these reservoirs is often complicated and becomes important, especially, if fractures provide primary pathways of fluid flow. In this paper a novel semi-analytical simulator was used to understand the pressure behavior of naturally fractured reservoir containing a network of discrete and/or connected finite and infinite-conductivity fractures. In this study an integrated interpretation methodology is applied to analyze well test data acquired in open hole section of exploration well drilled into highly fractured carbonate reservoir of Lower Eocene – Upper Cretaceous sediments on Patardzeuli field of Block XI-B, Republic of Georgia. The main steps consisted of explicitly modeling fractures - both wellbore-intersecting fractures and fractures located away from wellbore - using formation microimager data and calibrating the model to actual well test response using a unique novel mesh-free semi-analytical simulator designed for fractured reservoirs. Study presents the results of well test of one zone performed in highly fractured carbonate reservoir drilled in Patardzeuli field. The pressure-transient response confirmed the complexity of reservoir and dominant contribution to flow regimes from fractures. It is shown in this paper that there are many factors that dominate transient behavior of a well intersected by natural fractures, such as fracture conductivity, length, intensity and distribution, as well as whether fractures intersect the wellbore or not. Moreover, it was demonstrated that presence or absence of damage on wellbore-intersecting fractures in vicinity of wellbore will impact the pressure-transient behavior of reservoir and shape overall productivity of the well. The novelty of the approach is the analysis of the dynamic behavior using a unique semi-analytical pressure transient simulator for fractured reservoirs. The simulator can be used to obtain a response for arbitrarily distributed infinite and/or finite conductivity natural fractures within the reservoir by modeling them explicitly. In this study, it allowed to maximize the value of well tests by assessing the effect of fractures on reservoir dynamic behavior and obtain matrix and fracture parameters where conventional well test interpretation tools would be deemed unviable.
Korelskiy, Evgeny (Schlumberger) | Yildiz, Tabiat Tan (Schlumberger) | Urazaliev, Jenis (Schlumberger) | Goloborodko, Andrey (Schlumberger) | Orlov, Artem (Schlumberger) | Tirumanapali, Suman (Schlumberger) | Savinov, Roman (Schlumberger) | Akhmetov, Marat (Schlumberger) | Ivanov, Roman (Schlumberger)
Abstract Exploration drilling in the Samgori-Patardzeuli area started in 1974 for the Lower Eocene – Paleocene formations, during the exploration campaign oil discoveries were made in Middle Eocene sediments. The Samgori-Patardzeuli Middle Eocene delivered the bulk of the production in Georgia and is now a depeleted reservoir. Although more than 200 well have been drilled up to date, only 13 wells from them were drilled to the Lower Eocene, therefore Lower Eocene have not been studied sufficiently and gas reserves have not been estimated. Despite this, 29.97 million m of gas has been prodused so far from the Lower Eocene sediments. This paper describes the successful experience of drilling one of the deepest exploration well PAT-E1 on the Patardzeuli field to evaluate Lower Eocene gas reservoirs. Exploration drilling for oil and gas involves numerous risks related with limited information about geological structure and drilling conditions. Successful drilling of planned deep exploration well requires good understanding of hole stability to find the optimal mud properties, proper casing seat selection and out-of-the-box engineering solutions to reach well objectives. Multidisciplinary team, including drilling engineers, reservoir engineer, geologist, geomechanicist, petrophysicist, drilling engineer, mud engineer worked in collaboration to design and drill one of the deepest exploration well in the area. Interval from surface till Upper Eocene was characterized by offset wells, but most of decisions were made based on trial and error. Main problems in the upper sections were related with extreme borehole breakouts and severe losses, while the lower sections was known for losses and gas kick. The PAT-E1 well was successfully drilled to the main target in the Lower Eocene and penetrated down to the top of Upper Cretaceous formation with well TD at 5020 m. Elimination one of intermediate sections allows to decrease well construction time and costs with controlled risks of borehole breakouts and losses. Geological support allowed to place casing shoes in a very narrow safe interval to separate the interval of high breakout risk and total loss interval of fractured reservoir with abnormally low pore pressure. Real time pore pressure and fracture pressure prediction service in the lower sections allowed to monitor hole condition in real time and provided timely recommendations for well control. The PAT-E1 well is first deep exploration well that was sucsesfully drilled Upper Cretaceous formation on Patardzeuli field which allow to complete advanced formation evaluation and testing. Best practices developed while drilling this well will be applied for future safe drilling in the region.
Abstract The Government of Azerbaijan has signed a production sharing agreement (known as the "Contract of the Century" in Azerbaijan) with a consortium of international oil companies in 1994, which marked the beginning of the new development in the country's oil and gas history.1 This contract has signified a key milestone in transforming the economy of the country and hike in standards of living of Azerbaijani citizens following the collapse of the Soviet Union. This contract has produced one of the world's largest pipeline project taking Caspian energy resources across Azerbaijan, Georgia and Turkey to the world market. Called Baku-Tbilisi-Ceyhan (BTC) pipeline, this mega-infrastructure project operated by BP has delivered the best practice in the industry with key focus on environmental and social impact assessment and comprehensive mitigation measures with focus on building positive relationships with communities and people affected by the project activities. BP, as the responsible operator of the major oil and gas projects in the country, has demonstrated a special emphasis to community safety, community liaison and local stakeholder relations management.2 In furtherance of the goal of promoting and establishing the BTC project, the Governments of Azerbaijan, Georgia and Turkey have entered into an Inter-Governmental Agreement (IGA) and associated Host Government Agreement (HGA), which set out the legal and fiscal regime under which The Baku-Tbilisi-Ceyhan Pipeline Company (BTC Co.) may construct and operate the BTC project in each country. As a supplement to each HGA, BTC Co. signed with Governments of Azerbaijan, Georgia and Turkey a joint statement, which establishes a number of additional key commitments, including a commitment to implement the BTC Project consistently with the Organization for Economic Development and Cooperation (OECD) Guidelines on Multinational Enterprises and commitment to internationally recognized human rights principles in the context of security operations around the BTC pipeline.
Abstract Today, offshore Caspian has become one of the world's leading hydrocarbon provinces. The development of the region's offshore oil and gas fields and onshore pipelines has made Azerbaijan a focal point of the global energy market and a gateway through which international investments reach the Caspian region and beyond.1 Azerbaijan has a long oil and gas history, which was reinvigorated in 1994 when a consortium of major oil companies signed a Production Sharing Agreement (PSA) with the Government of Azerbaijan to explore and develop offshore Azerbaijan, which has been referred to as the "Contract of the Century". This has also triggered construction of the 1768 km long Baku-Tbilisi-Ceyhan (BTC) pipeline and other major projects now operated by BP. During the late 1980s and early 1990s, Azerbaijan endured the collapse of the Soviet Union, economic disintegration, and a devastating war with neighboring Armenia. 1995 Gross Domestic Product (GDP) was 42 percent of pre-independence levels and unemployment was endemic. Of a total population of 8 million, about 1 million Azerbaijanis were refugees or internally displaced persons who had fled areas occupied by Armenian forces. Another 2 million Azerbaijanis had left the country, mainly to find work.2 The Contract of the Century also provided the opportunity for the Azerbaijani private sector to rebuild itself by working with BP and associated service companies. However, to be successful Azerbaijani companies would have to compete with international firms for contracts, which demanded international quality levels. For most local companies this seemed an insurmountable obstacle.
Abstract BP Exploration Caspian Sea (BP Caspian) is the operator of a number of major projects in the Azerbaijan sector of the Caspian and Trans-Caucasus region. Exploration activities were initiated in 1994, since then the scope and diversity of exploration and production activities have expanded rapidly. The diversity of BP Caspian's operations, and the fact that they are carried out over three countries (Azerbaijan, Georgia and Turkey) has lead to a certain degree of legislative complexity. BP Caspian operates under a number of agreements between BP-led operating consortia and host country governments. These agreements, which include Production Sharing Agreements (PSAs), Host Government Agreements (HGAs) and Inter-Government Agreements (IGAs), establish many of the standards against which health, safety, security and environmental (HSSE) performance within BP Caspian is measured. The complicated nature of these regulatory requirements is the key driver for BP Caspian's compliance focused HSSE Management System. This paper describes the development and implementation of BP Caspian's HSSE Management System and provides additional detail on three key focus areas, namely: Legal and Other Requirements; Documentation; and Audit. Progress towards safe and green operations as a result of these elements of the Management System is then presented. Introduction BP Caspian is the operator of a number of major projects in the Azerbaijan sector of the Caspian and Trans-Caucasus region and is responsible for investment, project development and delivery on behalf of various project partnerships, in line with agreed management frameworks. BP Caspian has been represented in Azerbaijan since 1992 and has rapidly become its leading international investor and operator. Exploration activities were initiated in 1994, since then the scope and diversity of exploration and production activities have expanded rapidly. BP Caspian currently operates the following assets and facilities (see Figure 1):Six offshore facilities in the Azeri, Chirag, Guneshli (ACG) oil field and the Shah Deniz (SD) gas field. A major processing hub, Sangachal Terminal, where all hydrocarbons from offshore Caspian are processed before export. Three oil transportation pipelines from Sangachal Terminal to: Supsa Terminal on the Georgian Black Sea coast (Western Route Export Pipeline (WREP)), the Russian border (Northern Route Export Pipeline (NREP)) and Ceyhan Terminal on the Mediterranean coast of Turkey (Baku-Tbilisi-Ceyhan (BTC) pipeline). One gas transportation pipeline from Sangachal Terminal to the Georgian / Turkish border (South Caucasus Pipeline (SCP)).
ABSTRACT The study presents the analysis of the development of the Baku-Tbilisi- Ceyhan (BTC) project, which is a 1700-mile long pipeline project that starts from the Caspian Sea, passes through the three countries (Azerbaijan-Georgia-Turkey), and ends at the Mediterranean Sea, and its technical details together with a close examination of the strategic importance of BTC for the transit countries. The results focus on the Caspian Sea Transit Pipeline (CSTP) including its main obstacles and opportunities, potential benefits to the region, the BTC project presented as well. In conclusion, the impact and the role of BTC and CSTP on the European energy consumption is discussed. INTRODUCTION The Middle East, especially the Persian Gulf, had been the main energy resource supplier of Western World throughout the 20th century. The Caspian Sea region is expected to have a similar role, as a significant energy source for the western countries in the 21st century. For countries in the Caspian region that have the potential to utilize the energy resources, the main issue related with the energy transfer is the establishment of a politically reliable, cost efficient and environmentally safe energy transfer route. The Caspian region energy producing countries are establishing economically reliable, environmentally safe, and a secure energy transfer route to export its products into the world markets. This paper discusses the importance of the Caspian energy resources for European Union and the United States by evaluating the East-West energy corridor and the Caspian Sea Transit Pipelines and their first components the BTC-crude oil pipeline and the Baku-Tbilisi-Erzurum (BTE) gas pipeline respectively. The Caspian Sea status and claims of sides and its effects on East-West energy corridor are also discussed this paper. IMPORTANCE OF THE CASPIAN ENERGY RESOURCES The countries in the Caspian region have one of the world's largest untapped fossil fuel resources.