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Abstract: A naturally fractured reservoir may be divided vertically into several zones, i.e. gas cap, gas invaded, undersaturated oil, water invaded, and aquifer. Gravity drainage is the main oil producing mechanism in gas invaded zone. Depending on the wettability of thr reservoir rock, the main recovery mechanism in water invaded zone will be gravity drainage or imbibition for oil wet or water wet rock, respectively. The typical fractured oil reservoir with original reservoir pressure 5960 psia and temperature 225 ยฐF at the datum depth of 10500 ft was selected. Irap RMS and CMG black oil simulators were used to generate the reservoir structure and dynamic models. A sector of the reservoir was selected for the study the performance of gas and water injection. After getting a good history match, the reservoir sector model was run at different scenarios for optimising the well pattern and rate of injection production, for both gas and water injection processes. The simulation with the constructed dual porosity model, typical Iranian naturally fractured reservoirs showed that fluid and rock interaction properties i.e. wettability, relative permeability, and capillary pressure of both matrix and fracture network are governing parameters. Numerical simulation using dual porosity, dual permeability (DPDP) models showed that gas injection has much better performance from oil recovery point of view compare to water injection. Additionally the application of horizontal wells has a positive impact on both gas and water injection processes. INTRODUCTION Carbonate reservoir rocks show large variations in porosity and permeability between reservoirs, and even within the same reservoir. The fractured carbonate reservoirs, all behave the same from a high productivity point of view which is far more in excess of that which is expected from their rock matrix permeability. A fractured reservoir may be divided vertically into several distinct zones sometime in its depletion period. These zones are mainly: gas cap, gas-invaded, gassing, undersaturated oil, water invaded, and water zone. The gassing zone consists of the portion of the reservoir where the pressure of the matrix is below the prevailing bubble-point pressure. In the lower portion of this zone, where Sg < Sgc, a solution gas drive mechanism takes place in the known sense of it, except for the volume of gas transfer due to diffusion. When free gas reaches its critical saturation in the upper portion of gassing zone, gas moves upward due to its lower density than oil. Therefore, the recovery due to the solution-gas drive mechanism is mainly a function of the rate of pressure drop and the resulting effect determines the final fluid saturation in the blocks. In the under saturated portion of the reservoir two processes take place: a- expansion of the liquids and b- diffusion of gas through oil from matrix to the fracture. The diffusion process causes the oil in the matrix to lose some of its gas and therefore, oil from the fracture replaces the equivalent volume of lost gas.
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Louisiana > Alpha Field (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Carter Field (0.89)
- North America > United States > California > Sacramento Basin > Tracy Field (0.89)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- (2 more...)
Abstract: According to the current prognosis, the total oil production in the mature provinces is expected to decline within a few years. This trend can create a significant gap between hydrocarbon supply and demand in the certain regions of the world. Developing new offshore provinces and unconventional hydrocarbon reserves can reduce this production gap in the future. The IOR methods are also expected to reduce this production gap by bringing advanced technological solutions to boost oil recovery from mature fields, geologically complex low permeable and carbonate reservoirs in the future. Most of the IOR potential will come from the producing basins by reducing the risk and CAPEX of IOR projects, making the best use of the existing infrastructure and extending the production economic life of the fields. The present paper will review worldwide IOR experiences considering the limitations of the existing infrastructure, market access routes and regional economic framework. The current and future IOR strategies will be discussed. Environmental aspects are playing now more important role in the evaluation of the IOR strategies. Sequestration of greenhouse gases and developments in the environmentally sensitive offshore areas represent new IOR drivers and challenges in the same time. With the increasing number of the deep-sea developments, the subsea IOR methods will represent new opportunities. Similarities and differences between IOR practices in the Atlantic, Gulf of Mexico and the North Sea will be addressed. The authors will give a comparative review of the IOR methods, their application scale and achieved results to date in different geographies. The importance of screening and evaluation of IOR methods for timely decision on their field application will be emphasised. The examples from the industry show, that there are excellent opportunities for technology transfer among countries and operators. EOR Status Most of the current world oil production comes from mature fields. Increasing oil recovery from the aging resources is a major concern for oil companies and authorities. In addition, the rate of replacement of the produced reserves by new discoveries has been declining steadily in the last decade. Therefore, the increase of the recovery factors from mature fields under primary and secondary production will be critical to meet the growing energy demand in the coming years. Improved Oil Recovery (IOR) methods encompass Enhanced Oil Recovery (EOR) methods as well as new drilling and well technologies, intelligent reservoir management and control, advanced reservoir monitoring techniques and the application of different enhancements of primary and secondary recovery processes. It is well known that EOR projects have been strongly influenced by economics and crude oil prices. The initiation of EOR projects depends on the preparedness and willingness of investors to manage the EOR risk and economic exposure and the availability of more attractive investment options. In the U.S. chemical and thermal EOR projects have been in constant decline since mid 1980's, with gas injection methods as the preferred recovery methods in the last decade (Figure 1).
- South America > Brazil > Bahia (1.00)
- North America > United States > Texas (1.00)
- North America > Mexico (1.00)
- (6 more...)
- Geology > Rock Type > Sedimentary Rock (1.00)
- Geology > Geological Subdiscipline (0.94)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (0.47)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Marlim Field > Macae Formation (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Marlim Field > Lago Feia Formation (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Marlim Complex (0.99)
- (147 more...)
IMPROVED OIL RECOVERY TECHNOLOGY IN CHINA: STATUS & OUTLOOK
Shen, Ping Ping (Petrochina - Research Institute of Petroleum Exploration and Development (RIPED)) | Song, Jie (Petrochina - Research Institute of Petroleum Exploration and Development) | Zhu, Bin (Petrochina - Research Institute of Petroleum Exploration and Development)
Abstract: Approximately two thirds of reserves will not able to be recovered by the conventional waterflood development. With the rapid development of national economy, the demand of energy has been rising increasingly. Therefore, it is an inevitable trend to develop improved oil recovery (IOR) technology for the matured oilfields. In this paper, the essential procedures and results of the second potential assessment for IOR in China are presented, and the IOR pilots in recent years are summarized. At present, the displacement mechanism of the chemical system is not completely clear yet due to the complex geological condition, and the cost of the chemicals is still quite high. Consequently, the fundamental study on extensively improving oil recovery is carried out in this paper, and progress are made in molecular structure design of surfactant, development of geological prototype model, the physical simulation of the complex displacement system and the development of the chemical flood simulator. The paper also discussed the development tendency of IOR technology in China and further emphasized the importance of the fundamental study. PREFACE Most of China's onshore oilfields belong to continental deposits, with features of strong heterogeneity, high viscosity, etc., and oil recovery factor averaged only in the scope of 33%~35%. There may be two thirds of reserves (OOIP) remaining underground if oilfields are developed by conventional water-flood method. China's rapid developing economy leads to an ever-increasing demand for petroleum, therefore, how to further improve oil recovery of current developing oilfields is of importance and significance as well as a heavy task. China has been emphasizing on research and application of improved oil recovery (IOR) technologies and has achieved a great deal of improvement by years of efforts. Polymerflooding technology has gradually developed as one of the mature technologies: oil production by means of polymer flooding exceeded 11 million tons in 2001; the alkaline/surfactant/polymer (ASP) combination flooding technology has also been made a great deal of progress, exciting results have been achieved from indoor researches and field tests. During the years of 1987โ1990 and 1996โ1998, China National Petroleum Corporation(CNPC) had twice organized IOR technology evaluation concerning its potential, which systematically evaluated 17 oil regions(OOIP:101.36ร10t) based on technical and economic considerations(see Figure 1), determining and guiding the development strategy of IOR technology for China's onshore oilfields. (Figure in full paper) POTENTIAL EVALUATION OF IOR FOR CHINA'S ONSHORE OILFIELDS Establishing Standards for primarily screening IOR technology and developing evaluation software package The primary screening standard for IOR technology has been set up (see Table 1), and consequently a screening evaluation software package (see Figure 2) consisting of models of polymer flooding, ASP flooding, miscible gas flooding, immiscible gas flooding and economic evaluation has been developed by integrating technology and economy. More than 100 experts were organized to predict and evaluate IOR technology's potential. The reserve involved in this potential prediction and evaluation for IOR technology accounts for 72.6% of the developed OOIP, among which the OOIP by IOR primary screening occupied 78.7% of the evaluated OOIP.
- Africa > Cameroon > Gulf of Guinea (0.24)
- Asia > China > Heilongjiang Province (0.21)
- Government > Regional Government > Asia Government > China Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Asia > China > Xinjiang Uyghur Autonomous Region > Pubei Field (0.99)
- Asia > China > Xinjiang Uyghur Autonomous Region > Hami Basin (0.99)
- Asia > China > Jilin > Songliao Basin > Fuyu Field (0.99)
- (4 more...)
Abstract: The Takula Field is the most prolific oil field in the Republic of Angola. The field is located in the Block 0 Concession 40 km from the Malongo terminal in water depths of approximately 60 m. The Takula Field once accounted for one-third of Angola's total oil production. The Takula Field is comprised of seven stacked reservoirs. The field was discovered in October 1971 and placed on primary production in December 1982. Under primary production the field achieved rates of 130 MBOPD. A peripheral waterflood was initiated in the Vermelha reservoir in December 1990. The field achieved its peak production rate of 170 MBOPD in April 1995. In October 1992, Improved Oil Recovery technology was applied to the Mesa reservoir with horizontal infill wells. Well TK-F8 was the first horizontal well in Angola. Horizontal well technology was applied to the Vermelha reservoir and was followed by the first Angolan multilateral well in January 1998. In July 1999, the Mesa reservoir was placed on waterflood and became the first waterflood in Angola to rely solely on lateral wells. This reservoir management strategy was later applied to the Northwest Takula fault block and the S7 flow unit of the Vermelha reservoir to aid in the development of lower reservoir quality regions. Topics to be discussed include:Geology of the Greater Takula Area Exploration history of the field Primary Production including: fabrication, drilling, and production experiences; reservoir surveillance and management strategies Secondary Production including: transition experiences going from primary to secondary production, infrastructure modifications, and adjustments to the reservoir surveillance and management strategies Application of IOR technologies including: single- and multi-lateral infill wells and lateral-well developments of poorer reservoir quality regions and flow units Current challenges and future plans for the field including: maintaining base production from a mature reservoir with aging infrastructure and heightened environmental awareness INTRODUCTION The partnership between the Republic of Angola, its people, and the Cabinda Gulf Oil Company (CABGOC) began informally with geological reconnaissance surveys of the province of Cabinda in 1954. This partnership was formalized in 1957, with the award of exclusive hydrocarbon exploration and development rights in the province to CABGOC. During the 1990's, the Republic of Angola became one of the premier oil producing regions of the world. With oil production exceeding 900 MBOPD (143.1x103 m3/d) in 2003, the Republic of Angola is the second largest crude oil producer in sub-Saharan Africa and the seventh largest exporter of crude oil to the USA; exporting over 350 MBOPD (55.6x103 m3/d), approximately 5 percent of the total US demand. The Takula Field, situated in Blocks 44, 45, 56, and 57 of Area A in the Block 0 Concession (see Figure 1), is the largest producing oil field in the Republic of Angola. It is located approximately 28 km west of the nearest landfall and 40 km northwest of the Malongo terminal in water depths ranging from 55 to 65 m.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (1.00)
- Geology > Structural Geology > Tectonics (0.95)
- Geology > Sedimentary Geology > Depositional Environment (0.68)
- Geology > Geological Subdiscipline > Stratigraphy (0.68)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.46)
- Europe > United Kingdom > North Sea > Central North Sea > Moray Firth > Moray Firth Basin > Fladen Ground Spur > Block 15/17 > Piper Field > Sgiath Formation (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Moray Firth > Moray Firth Basin > Fladen Ground Spur > Block 15/17 > Piper Field > Piper Formation (0.99)
- Africa > Angola > South Atlantic Ocean > Lower Congo Basin > Area B > Block 0 > Greater Vanza Longui Area (GVLA) Field > Pinda Formation (0.99)
- (7 more...)