Three-Dimensional Physical Simulation of Heavy Oil Exploitation by Hot Solvent Injection

To improve the thermal effects of solvents on heavy oil reservoirs and realize the combined action of multiple flooding mechanisms, such as solvent heating and extraction, without steam mixing, based on the M Block heavy oil reservoir in Canada, three sets of comparative hot solvent-assisted gravity drainage experiments under different temperatures and pressures were carried out through an indoor three-dimensional (3D) physical simulation device. The development characteristics of the solvent chamber in the hot solvent-assisted gravity drainage technology were studied under different pressures and temperatures, and the recovery factor, cumulative oil exchange rate, and solvent retention rate were analyzed. The results showed that due to the effect of gravity differentiation, the development morphology of the solvent chamber could be divided into three stages: rapid ascent, lateral expansion, and slow descent. When the temperature was constant, the reservoir pressure decreased, the recovery rate increased, the cumulative oil exchange rate increased, and the solvent retention rate decreased; when the pressure was constant, the temperature increased, the viscosity of heavy oil decreased, the recovery rate increased, the cumulative oil exchange rate increased, and the solvent retention rate was low. Additionally, the study also showed that for hot solvents in different phases, the use of hot solvent vapor not only required less injected solvent but also exhibited a high oil production rate, which shortened production time and reduced energy consumption. Moreover, the oil recovery rate was higher than 60%, the solvent retention rate was lower than 10%, and the cumulative oil exchange rate was higher than 3 t / t , which constituted better economic benefits and provided a reliable theoretical basis for onsite oilfield applications.

Analysis Of The Clean Water Service Capacity of The Regional Drinking Water Company (PDAM) In Cirebon Regency, Indonesia

The provision of clean water for the community is not optimal, so that the distribution of water is not evenly distributed. The distribution network of PDAM Tirta Jati serves Taman Tukmudal Indah Housing, Sumber District, which is supplied from Cigusti springs with a gravity drainage system, currently reaching 1,037 units of house connections. Geographic Information Systems visualize spatial data related to positions on the earth’s surface. Analysis of Clean Water Service Capacity in the discussion of clean water quality that has been tested in the Bandung Institute of Technology laboratory. The samples tested for analysis showed that the clean air quality met the quality standards. The standard of clean water needs is 60 liters/person/day. Continuity shows that the clean air pressure is not in accordance with the minimum standards that have been determined because most of the air pressure is still low. The lowest air pressure = 1.00 meters, and the highest = 50 meters, the lowest average air pressure is at 22:00 and the highest is at 09:00. The minimum air pressure that must be met is 1.0 atm. This pattern is expected to maintain the quality, quantity, and continuity of clean water services.

The effect of gravity drainage mechanism on oil recovery by reservoir simulation; a case study in an Iranian highly fractured reservoir

A comprehensive reservoir simulation study was performed on an oil field that had a wide fracture network and could be considered a typical example of highly fractured reservoirs in Iran. This field is located in southwest of Iran in Zagros sedimentary basin among several neighborhood fields with relatively considerable fractured networks. In this reservoir, the pressure drops below the saturation pressure and causes the formation of a secondary gas cap. This can help to better assess the gravity drainage phenomenon. We decided to investigate and track the effect of gravity drainage mechanism on the recovery factor of oil production in this field. In this study, after/before the implementation of gas injection scenarios with different discharges, the contribution of gravity drainage mechanism to the recovery factor was found more than 50%. Considering that a relatively large number of studies have been conducted on this field simultaneously with the growth of information from different aspects and this study is the last and most comprehensive study and also the results are extracted from real field data using existing reservoir simulators, it is of special importance and can be used by researchers.

Policy Insights to Accelerate Cleaner Steam-Assisted Gravity Drainage Operations

The literature is replete with concerns on the environmental impact of steam-assisted gravity drainage (SAGD), but rigorous analysis of its improved environmental performance over the past 20 years remains unresolved, as well as the underlying technological reasons for this improvement. Here, we present an analysis of historical and future greenhouse gas (GHG) performance of SAGD operations in Alberta, Canada, considering for the first-time factors that affected technology deployment. Depending on the case, the results show a reduction of 1.4–24% of SAGD GHG intensity over the past 12 years. Improvements mainly arise from incremental changes adopted based on technical, environmental, socio-economic, and policy drivers. Considering these factors, we propose policy interventions to accelerate further reductions of GHG emissions. However, if similar behaviour from industry continues, anticipated GHG intensity reduction will range between 6.5–40% by 2030, leading to an intensity between 58 and 68 kgCO2e/bbl. It still remains unclear if in situ oil sands bitumen extraction will reach current conventional oil emission intensities. Thus, we suggest that the SAGD industry drastically accelerate its deployment of cleaner oil sands extraction technologies considering the policy insights proposed.

Modeling Challenges for Cold Gas Oil Gravity Drainage cGOGD Development of a Naturally Fractured Reservoir and Lessons Learnt –A Case Study, North Oman Oil Field

Global experience in cold Gas Oil Gravity Drainage (cGOGD) recovery with crestal gas injection of infield produced gas is very limited, but is a proven economic recovery method for fractured carbonate reservoirs in North Oman. Despite decades of research in nature of fluid flow in fracture-matrix media and application of sophisticated tools in building fracture model of a naturally fractured reservoir (NFR) reliable prediction of the GOGD production performance often proved elusive. Characterization of fracture networks and modeling of matrix-fracture transfer function, gravity induced fluid flow in heterogeneous matrix media especially in case of capillary discontinuity due to tight interbedded matrix and capillary pressure hysteresis are the key challenges for reservoir modeller. Re-infiltration of oil into lower matrix blocks, matrix permeability, fracture density and spacing, wettability and reservoir fluid properties have significant impact on the well and field performance. The risk posed due to undermining the key modeling parameters have huge implication on facility design, subsurface concept and value of the project. The challenges in upscaling the fracture properties in a range of grid scale, experimental design for history matching and uncertainty analysis, understanding the oil rim development in leached zone and numerical options are some of the key aspects which have been illustrated in this paper. The field being on primary production since 1985, showed poor recovery and high water cut. Multi-episodic tectonic events resulted in variable fracture intensity and fracture permeability anisotropy. This study investigated the effects of the parameters on cGOGD recovery process, operating strategy (e.g., gas injection rate and liquid offtake) and on the overall field performance. The development decisions are not simply relied upon the dynamic simulator results, but an integrated understanding from comprehensive analytical calculations for multiple recovery mechanism such as fluid expansion, fracture oil displacement, gravity drainage from background matrix and leached zone and analogue field GOGD performance were taken into consideration. The subsurface development decisions such as producer location with respect to faults and lineament, well pattern & spacing, producer depth, gas injector locations, gas injection scenarios, aquifer pump-out wells and maximum off-take rate were analyzed and optimum decision could be taken from multi-scenario modeling studies. The GOGD development could increase the field recovery up to ~9% at low UTC and positive NPV. A pragmatic and integrated modeling workflow with multi-scenario modeling approach was pursued to address the development risk which facilitated the field to be economically developed. The key modeling challenges have been highlighted for GOGD modeling process with gas recycling option of development which can be replicated in similar fields in PDO.

Recommended dependence for hydraulic calculation of gravity drainage networks in order to improve the ecological well-being of cities

In the submitted article comparison of two calculated dependences - formulas of A. Chézyand and N.F. Fedorov used for the hydraulic calculation of gravity drainage networksare presented. For a specific example, dependence is revealed - the A. Chézy formula, which gives the highest accuracy when calculating the hydraulic slope of a gravity pipeline. The appearance of the A. Chézy formula has been clarified due to the introduction of the concept of the reduced inner diameter of the pipes. The graph of the dependence i=f (dred) is plotted, indicating that the refined form of the A. Chézy formula is more accurate. It is recommended to use the A. Chézy formula in a refined form for the hydraulic calculation of gravity drainage networks. It is proposed to develop calculation tables for the hydraulic calculation of drainage networks with internal deposits. The analysis of the calculated dependencies for the hydraulic calculation of gravity drainage networks with internal deposits presented in the paper allows recommending for practical use the formula of A. Chézy refined by the authors, according to which the authors propose to develop the Reference manual “Tables for the hydraulic calculation of gravity drainage networks with internal deposits”.