Indonesia’s oil reserves continue to decrease each year. The amount of oil produced is greater than the amount of new reserves discovered. To overcome this imbalance, various efforts have been made by the government in increasing oil lifting. In addition to exploration activities, other efforts that can be done to improve oil lifting are through Improved Oil Recovery (IOR).
Since the establishment of SKK Migas, a total of 431 oil and gas Field Development Plans (FDP) have already been approved by the Government of Indonesia (as of December 2017) and about 31 of them were already using IOR methods (water flood and steam flood). Along with the sharp decline rate in Indonesia, more IOR projects are needed to restrain the decline oil rate in Indonesia. To attract and help contractors so they are willing to do the IOR projects, the Government of Indonesia offer an incentives such as investment credit and/or interest of cost recovery so that the IOR projects can be developed more economically. Moreover, there are some tools which these contractors may use to improve the economical nature of their projects, such as DMO Holiday, Depreciation Acceleration, Shared First Tranche Petroleum, Split Changes, and many more.
The purpose of this paper, is to obtain the average Production Costs of IOR Projects in Indonesia, which divided into 3 different IOR areas (North Sumatera, South Sumatera, and Kalimantan) based on the 31 IOR FDP projects. The data of the 31 IOR Projects were collected and afterwards the Profitability Index and Development Cost were calculated and distributed to those aforementioned areas.
The result of this paper showed that the lowest average production cost was in North Sumatera by 10 US$ per barrels and the highest average production cost of IOR projects in Indonesia was in Kalimantan by 25 US$ per barrels which remain lower than the current oil price. Based on the obtained production cost above, it can be concluded that the Indonesian IOR Projects are economically acceptable and hopefully can attract more contractors to propose IOR Projects in Indonesia.
The compositional flow simulation model was frequently used to evaluate the miscible water alternating CO2 flooding (CO2-WAG). The uncertainty and sensitivity analysis have to be conducted to examine the parameters mostly affecting the performance of the process. Accordingly, multiple simulation runs require to be constructed which is a time-consuming procedure and finally increase the computational cost. This paper presents a simplistic approach to assess the miscible CO2-WAG flooding in an Iraqi oilfield through developing a statistical proxy model. The Central Composite Design (CCD) was employed to build the proxy model to determine the incremental oil recovery (ΔFOE) as a function of seven reservoir and operating parameters (permeability, porosity, ratio of vertical to horizontal permeability, cyclic length, bottom hole pressure, ratio of CO2 slug size to water slug size, and CO2 slug size). In total, 81 compositional simulation runs were conducted at field-scale to establish the proxy model. The validity of the model was investigated based on statistical tools; the Root Mean Squared Error (RMSE), R-squared statistic and the adjusted R-squared statistic of 0.0095, 0.9723 and 0.9507 confirmed the reliability of the model. The most influential and the optimum values of the parameters that lead to the higher ΔFOE during miscible CO2-WAG process were identified through proxy modeling analysis. The developed model was created based on the Nahr Umr reservoir in Subba oilfield and can be applied to roughly estimate the ΔFOE during the miscible CO2-WAG process at the same geological conditions as Nahr Umr reservoir.
With maturing oil fields there is an increasing focus on improving the oil recovery factor and pushing the envelope toward a 70% target. This target is indeed very challenging and depends on a number of factors including enhanced oil recovery (EOR) methods, reservoir heterogeneities, displacement efficiency, and reservoir sweep. Other factors also play a role including vertical sweep due to flow behind the casing, well integrity issues, presence of conductive faults, or fractures. Proper surveillance performed to evaluate the injectant plume front, reservoir conformance, well connectivity, assessment of the integrity of wells, and other factors can be crucial for the success of the project and its future development.
The paper discusses special downhole logging techniques including a set of conventional multiphase sensors alongside high precision temperature (HPT) and high-definition spectral noise logging (SNL-HD). It was run to provide complete assessment of the injection – production distribution and any associated well integrity issues that might impair the lateral sweep of injectants into the target layer. This will be done for an injector and producer pair near the wellbore area. The operation was carried out with a tool string that contained no mechanical parts and was not affected by downhole fluid properties. It was conducted under flowing and shut-in conditions to identify flow zones and check fracture signatures. It also provided multiphase fluid velocity profiles.
The results of the survey allowed for in-depth assessment of borehole and behind casing flow, confirming lateral continuity, and provided an assessment of production-injection outside the pay zone. Results will allow for better well planning and anticipation of possible loss of well integrity that might impair production in the future. Combining the behind casing flow assessment with borehole multiphase flow distribution can be used for production optimization by sealing unwanted water contributing zones.
Liang, Jiabo (CNOOC Iraq Limited) | Jin, Liping (CNOOC Iraq Limited) | Li, Wenyong (CNOOC Iraq Limited) | Li, Qiang (CNOOC Iraq Limited) | Laaby, Hussein Kadhim (Missan Oil Company) | Ammar, Ali Jabbar (Missan Oil Company) | Tayih, Ali Ouda (Missan Oil Company) | Muteer, Raad Fahad (Missan Oil Company) | Saadawi, Hisham N H (Baker Hughes, a GE company) | Harper, Christopher (Baker Hughes, a GE company) | Tuck, Jon O. (Baker Hughes, a GE company) | Fang, Yongjun (Baker Hughes, a GE company)
CNOOC Iraq Limited operates three oil fields in Missan Province in Iraq. They are all large onshore oilfields located 350 kilometers southeast of Baghdad. In order to support reservoir pressure, plans are underway to implement a water injection scheme. The injection water comes from three different sources; produced water, aquifer water as well as river / agricultural water. Considering the nature and varying chemistry of the source water, particular attention had to be given to selecting the material for the water injection wells. This paper describes the approach adopted in selecting the materials for Missan fields' water injection system.
AL-Rashidi, Hamad (Kuwait Oil Company) | AL-Azmi, Waled (Kuwait Oil Company) | AL-Azmi, Talal (Kuwait Oil Company) | Ahmed, Ashfaq (Kuwait Oil Company) | Muhsain, Batoul (Kuwait Oil Company) | Mousa, Saad (Kuwait Oil Company) | AL-Kandari, Noor (Kuwait Oil Company) | AL-Sabah, Fahad (AL-Thurya) | AL-Hajri, Mohsen (BG) | AL-Mutwa, Bandar (AAA)
Crude oil production in Um-Ghdair field is consider one of the most complex operational activities in Kuwait Oil Company due to high water cut percentage, asphaletene flocculation, high viscosity and tight emulsion phenomena. As the fluid travels through the reservoir, wellbore, flowline, all the way to the gathering center, the state of initial equilibrium is disturbed leading to change in the chemical composition of the crude oil. As pressure and temperature continue to drop, and gas escapes, more asphaltenes and heavy components may continue to flocculate all the way throughout the system until the petroleum reaches its final destination. In this pilot project, asphaltene inhibitor and viscosity reducer agents were selected for reducing oil viscosity and breaking the tight emulsion phenomena in the selected piloting well in Um-Ghdair field. It was noticed that there is an asphaltene compounds flocculate in the interface between oil and water leading to increase crude oil viscosity. The best two among 22 chemical formulations tested through the screening process at lab scale and take it to pilot stage. Additionally, the pilot study examined the influences effective for surfactants such as water composition, temperature, concentration, pH and total dissolved solids. It was noticed that the viscosity reduction and the water separation improve with increasing surfactant concentration and increasing temperature up to 50 F. Two formulations were selected based on cost effective optimal concentrations of surfactant that identified from the bottle test. The pilot has been implemented successfully in the field, resulting a reduction in non-production time and increase the oil mobility from the reservoir.
Alhuraishawy, Ali K. (Iraqi Ministry of Oil / Reservoir and Fields Development Directorate) | Jaber, Ahmed Khalil (Iraqi Ministry of Oil / Reservoir and Fields Development Directorate) | Aljawad, Sameer Noori (Iraqi Ministry of Oil / Reservoir and Fields Development Directorate) | Bai, Baojun (Missouri University of Science and Technology) | Wei, Mingzhen (Missouri University of Science and Technology) | Baker, Hussein Ali (Baghdad University) | AL-Bazzaz, Waleed Hussien (Kuwait Institute for Scientific Research)
The limitations of oil recovery from carbonate reservoirs are fractures and oil-wet conditions. To overcome the reservoir heterogeneities and reduce fracture transmissibility, preformed particle gel was applied in injector wells. Experimentally, low salinity waterflooding was applied to change the core wettability from oil-wet to water wet for enhanced oil recovery. However, both processes have limitations that cannot be resolved using a single method. A nonuniform fracture width and uniform fracture width models were built using carbonate cores to evaluate the coupling low salinity waterflooding and preformed particle gel in fractured cores and how could be used to improve in-depth water diversion treatment. The results showed that low salinity waterflooding improved in-depth water diversion when injected after PPG directly while seawater showed less effect than low salinity waterflooding. Also, the uniformity of fracture had a significant effect on plugging efficiency oil recovery factor from fractured reservoirs.
Moreno Ortiz, Jaime Eduardo (Schlumberger) | Gossuin, Jean (Schlumberger) | Liu, Yunlong (Schlumberger) | Klemin, Denis (Schlumberger) | Gurpinar, Omer (Schlumberger) | Gheneim Herrera, Thaer (Schlumberger)
Challenges on EOR process upscaling have been discussed extensively in the industry and effects of diffusion, dispersion, heterogeneity, force balance and frontal velocity -among others, recognized and qualified, along with the importance of understanding the numerical model finite difference equations and modeling strategy. Augmenting the upscaling complexity is the often-limited understanding/data on the EOR displacement at different scales (from micro to full field), including the EOR agent/rock/fluid interactions that is often available at the early stages of the EOR process de-risking.
A common denominator for the EOR process characterization and upscaling (along with the discretization of the displacement) is the non-uniqueness nature of the problem. As the complexity of numerical representation of the EOR process increases (thus increasing data characterization requirements), so does the number of plausible solutions and challenges when dealing with an otherwise incomplete dataset. Digital rock has evolved as a strong alternative to complement laboratory corefloods, allowing for EOR agent optimization on a high-resolution digital representation of the pore structure, detailed digital fluid model of both reservoir fluids and EOR agents and physical rock-EOR agent-reservoir fluid interaction, thus providing several calibration points to ensure the finite-difference model calibration and upscaling preserve the process behavior.
This paper discusses the use of digital rock solutions on the EOR deployment, particularly on translating the results to numerical finite difference models, addressing the inherent laboratory measurement uncertainty and proposing a fit-for-purpose multi-scale upscaling strategy that addresses both effects of heterogeneity and EOR agent characterization during the upscale process.
This paper addresses the challenges of chemical flooding upscaling, particularly polymer by using a real-life polymer injection case where digital rock, corefloods and more importantly pilot results are available to test and validate our observations. Using a polymer coreflood and digital rock results as input, numerical finite difference simulation models were built and calibrated to effectively reproduce the displacement physics observed on both digital rock and corefloods, digital flood results were used to bridge the laboratory-to-numerical model step by providing effective upscaled polymer properties as well as intrinsic rock properties such as relative permeability and capillary pressures, which are then taken through a series of multi-scale finite difference models to identify, validate and quantify upscaling requirements, addressing polymer deformation through pore throats and effective simulation viscosity. Digital rock is used to rank and resolve ambiguity on the finite difference model calibration by providing an otherwise rare opportunity to visualize the displacement in the 3D space. The analysis shed a new light on fluid-fluid and fluid-rock interaction at pore scale and enabled us to improve on the finite difference model generation and polymer properties.
Dong, Xiaohu (China University of Petroleum, Beijing) | Liu, Huiqing (China University of Petroleum, Beijing) | Lu, Ning (China University of Petroleum, Beijing) | Zheng, Aiping (Xinjiang Oilfield Company, CNPC) | Wu, Keliu (China University of Petroleum, Beijing) | Xiao, Qianhua (Chongqing University of Science & Technology) | Wang, Kung (University of Calgary) | Chen, Zhangxin (University of Calgary)
Considering the non-uniform steam conformance of conventional horizontal well, dual-pipe steam injection technique has currently demonstrated technical potential for improving heavy oil recovery. It can delay the occurrence of steam fingering and homogenize the steam injection profile along horizontal wellbore. But in some field tests, it is observed that the results were far greater than such an approach would have justified. In addition, the actual physics are still unclear, and not demonstrated. In this paper, first, we built a cylindrical wellbore physical model to experimentally study steam injection profiles of a single pipe horizontal well and a concentric dual-pipe horizontal well. Thus, the heat and mass transfer behavior of steam along horizontal well with a single-pipe well configuration and a dual-pipe well configuration was addressed. Subsequently, considering the effect of pressure drops and heat loss, a semi-analytical model for the gas-liquid two-phase flow in horizontal wellbore was developed to numerically match the experimental observation. Next, a sensitivity analysis on the physical parameters and operation properties of a steam injection process was conducted. The effect of the injection fluid type was also investigated.
Experimental results indicated that under the same steam injection condition, an application of the dual-pipe well configuration can significantly enhance the oil drainage volume by about 35% than the single-pipe well configuration. During the experiments, both a temperature distribution and liquid production along the horizontal wellbore were obtained. A bimodal temperature distribution can be observed for the dual-pipe well configuration. From this proposed model, an excellent agreement can be found between the simulation results and the experimental data. Because of the effect of variable-mass flowing behavior and pressure drops, the wellbore segment closed to the steam outflow point can have a higher heating radius than that far from the steam outflow point. From the results of sensitivity analysis, permeability heterogeneity and steam injection parameters have a tremendous impact on the steam injection profile along wellbore. Compared with a pure steam injection process, the co-injection of steam and NCG (non-condensable gas) can improve the effective heating wellbore length by over 25%. Furthermore, this model is also applied to predict the steam conformance of an actual horizontal well in Liaohe oilfield. This paper presents some information regarding the heat and mass transfer of a dual-pipe horizontal well, as well as imparts some of the lessons learned from its field operation. It plays an important role for the performance evaluation and remaining reserve prediction in a dual-pipe thermal recovery project.
Ho, Yeek Huey (Petroliam Nasional Berhad, PETRONAS) | Ahmad Tajuddin, Nor Baizurah (Petroliam Nasional Berhad, PETRONAS) | Elharith, Muhammed Mansor (Petroliam Nasional Berhad, PETRONAS) | Dan, Hui Xuan (Petroliam Nasional Berhad, PETRONAS) | Chiew, Kwang Chian (Petroliam Nasional Berhad, PETRONAS) | Tan, Kok Liang (Petroliam Nasional Berhad, PETRONAS) | Tewari, Raj Deo (Petroliam Nasional Berhad, PETRONAS) | Masoudi, Rahim (Petroliam Nasional Berhad, PETRONAS)
Managing a 47-year brownfield, offshore Sarawak, with thin remaining oil rims has been a great challenge. The dynamic oil rim movement has remained as a key subsurface uncertainty especially with the commencing of redevelopment project. A Reservoir, Well and Facilities Management (RWFM) plan was detailed out to further optimize the development decisions. This paper is a continuation from SPE-174638-MS and outlines the outcome of the RWFM plan and the results’ impact towards the development decisions, such as infill well placement and gas/water injection scheme optimization. Key decisions impact by the RWFM findings are highlighted.
One of the RWFM plans is oil rim monitoring through saturation logging to locate the current gas-oil contact (GOC) and oil-water contact (OWC). Cased-hole saturation logs were acquired at the identified observation-wells across the reservoir to map time-lapse oil rim movement and its thickness distribution. Pressure monitoring with regular static pressure gradient surveys (SGS) as well as production data, helped to understand the balance of aquifer strength between the Eastern and Western flanks. Data acquisition opportunity during infill drilling were also fully utilized to collect more solid evidences on oil rim positions, where extensive data acquisition program, including conventional open-hole log, wireline pressure test, formation pressure while drilling (FPWD) and reservoir mapping-while-drilling, were implemented.
The timely collection, analysis and assimilation of data helped the team to re-strategize the development / reservoir management plans, through the following major activities: Re-strategizing water and gas injection plan to balance back oil rim between the Eastern and Western flanks, through deferment of drilling water injectors, optimization of water and gas injectors location and completion strategies due to stronger aquifer encroachment from east and south east. Optimizing infill wells drainage points where 2 wells were relocated based on cased-hole logs, as the first well original location was swept and the second well was successfully navigated through the oil rim using reservoir mapping-while-drilling techniques coupled with cased-hole log results. This resulted in securing an oil gain of 4000 BOPD from these 2 wells. Optimizing infill wells location and planning an additional infill well with potential additional oil gain of approximately 2000 BOPD. The understanding of current contact and aquifer strength from the surveillance data assisted in identifying fit-for-purpose technology for the new wells such as the application of viscosity-based autonomous inflow control device which assisted in placing the well closer to GOC due to the observed rapid rising of water table, this will help sustaining the well life.
Re-strategizing water and gas injection plan to balance back oil rim between the Eastern and Western flanks, through deferment of drilling water injectors, optimization of water and gas injectors location and completion strategies due to stronger aquifer encroachment from east and south east.
Optimizing infill wells drainage points where 2 wells were relocated based on cased-hole logs, as the first well original location was swept and the second well was successfully navigated through the oil rim using reservoir mapping-while-drilling techniques coupled with cased-hole log results. This resulted in securing an oil gain of 4000 BOPD from these 2 wells.
Optimizing infill wells location and planning an additional infill well with potential additional oil gain of approximately 2000 BOPD.
The understanding of current contact and aquifer strength from the surveillance data assisted in identifying fit-for-purpose technology for the new wells such as the application of viscosity-based autonomous inflow control device which assisted in placing the well closer to GOC due to the observed rapid rising of water table, this will help sustaining the well life.
This paper highlights the importance of data integration from geological knowledge, production history, reservoir understanding and monitoring through regular SGS and time-lapse cased-hole saturation logging, coupled with extensive data acquisition during infill drilling. By analyzing and integrating the acquired data, project team can then confidently re-strategize and successfully execute the complex mature oil-rim brownfield redevelopment.
Sidek, Sulaiman (PETRONAS Carigali Sdn. Bhd.) | M Hatta, Siti Aishah (PETRONAS Carigali Sdn. Bhd.) | Goh Hui Lian, Kellen (PETRONAS Carigali Sdn. Bhd.) | Tan, Kok Liang (PETRONAS Carigali Sdn. Bhd.) | M Yusuf, M Hafizi (PETRONAS Carigali Sdn. Bhd.) | Tanf Ye Lin, Catherine (PETRONAS Carigali Sdn. Bhd.) | Mawardi, M Hizbullah (PETRONAS Carigali Sdn. Bhd.) | Hamzah, Haziqah (PETRONAS Carigali Sdn. Bhd.) | Masngot, Ainul Azuan (PETRONAS Carigali Sdn. Bhd.) | Jeffry, Suzanna Juyanty M (PETRONAS Carigali Sdn. Bhd.) | Riyanto, Latief (PETRONAS Carigali Sdn. Bhd.) | Samaile, Eddy (PETRONAS Carigali Sdn. Bhd.) | Ahmat Kamis, Azman (PETRONAS Carigali Sdn. Bhd.)
Flow assurance has been a big focus of oil and gas operation in ensuring the delivery of the targeted production. A few fields located offshore Malaysia have been experiencing solid deposition inside tubing and stable micro-emulsion from early stage of their life. Oil production from Field W begin in January 2003, unfortunately when the wells were first opened-up it was observed to produce viscous emulsion and the production decline rapidly. Multiple analyses and efforts, including chemical and mechanical treatments, conducted over the years with minimal success. The damaging mechanism was determined to be caused by rare High Molecular Weight Organic Deposit (HMWOD) that have caused a significant pressure drop in the tubing, which consequently restrict oil production and tested to only disperse at above 100°C. It was suspected that the organic deposit was a naturally-occurring component of the crude oil itself, separating from the bulk of the crude as a consequence of the fluids movement towards the wellbore and the consequent drop in fluid pressure.
This paper focuses on the step-by-step workflow developed to identify the solid deposition, laboratory testing, treatments conducted and the result of different chemical treatments in Field W. The ultimate effort was by developing an advanced eco-friendly nano-fluid to remediate the rare issue of HMWOD and high melting point deposit in the field. The nano-fluid pilot treatment was conducted in 2014 and successfully rejuvenate the well with total of 20,000bbl incremental oil volume. Early 2018, subsequent treatments were conducted that contributed substantial improvement to the field production and at lower total treatment cost. This advanced chemical using nano-fluid technology concept is deemed feasible and will be further replicated in other fields.
This paper is highly beneficial to operators, petroleum and flow assurance engineers experiencing flow assurance issue on organic scale such as microcrystalline wax, high molecular weight wax and stable emulsion in the crude production. This paper also promotes the use of nano-fluid technology as part of the solution to flow assurance issue in Oil and Gas industry.