Sorop, Tiberiu Gabriel (Shell Global Solutions International) | Suijkerbuijk, Bart M.J.M. (Shell Global Solutions International) | Masalmeh, Shehadeh K (Shell Technology Oman) | Looijer, Mark T. (Shell Global Solutions International) | Parker, Andrew R (Shell Global Solutions International) | Dindoruk, Deniz M (Shell Exploration & Production Co) | Goodyear, Stephen Geoffrey (Shell E&P UK) | Al-Qarshubi, Ibrahim S.M. (Shell Global Solutions International)
Low Salinity Waterflooding (LSF) is an emerging IOR/EOR technology that can improve oil recovery efficiency by lowering the injection water salinity. Field scale incremental oil recoveries are estimated to be up to 6% STOIIP. Being a natural extension of conventional waterflooding (WF), LSF is easier to implement than other EOR methods. However, the processes of screening, designing and executing LSF projects require an increased operator competence and management focus compared to conventional waterflooding. This paper discusses the practical aspects of deploying LSF in fields, focusing on the maturation stages, while highlighting the key success factors.
LSF deployment starts with a portfolio screening against specific surface and subsurface screening criteria to prioritize opportunities. Next, the identified opportunities are run through reservoir conditions SCAL tests to quantify the LSF benefits, while de-risking the potential for any injectivity loss due to clay swelling or deflocculation. Standardized LSF SCAL protocols have been incorporated into the general WF guidelines, so that any suitable new WF project conducts LSF SCAL. For mature waterfloods, this SCAL program provides additional reservoir condition relative permeability data, enabling operating units to optimize well and reservoir management (WRM). The next steps in the process are production forecasting, facilities design, and project economics for the LSF opportunity. The multidisciplinary nature of LSF deployment requires integrated (sub)surface technology teams closely collaborating with R&D and asset teams. The standardization of the facilities design, including cost models, can significantly accelerate the deployment effort.
In Shell, LSF is currently at different stages of deployment around the world and across the whole spectrum of WF projects, from the rejuvenation of brown fields to green field developments (offshore and onshore). The LSF deployment effort is combined with the screening of other EOR technologies, to identify where LSF may be able to unlock additional value by creating the appropriate conditions for subsequent chemical flooding.
Castro, Ruben Hernan (ECOPETROL, S.A.) | Maya, Gustavo Adolfo (Ecopetrol SA) | Sandoval, Jorge (Ecopetrol SA) | Leon, Juan Manuel (Ecopetrol SA) | Zapata, Jose Francisco (Ecopetrol SA) | Lobo, Adriano (Ecopetrol SA) | Villadiego, Darwin Oswaldo (ECOPETROL, S.A.) | Perdomo, Luis Carlos (ECOPETROL, S.A.) | Cabrera, Fernando Ariel (TIORCO, Inc.) | Izadi, Mehdi (TIORCO, Inc.) | Romero, Jorge Luis (TIORCO Inc) | Norman, Charles (TIORCO, Inc.) | Manrique, Eduardo Jose (TIORCO, Inc.)
Dina Cretaceous Field is located in the Upper Magdalena Valley (UMV) Basin, Colombia. Dina Field operated by ECOPETROL S.A. (discovered, 1969) started peripheral water in 1985. Based on high water cuts (96%) and recovery factors of 32%, comprehensive enhanced oil recovery (EOR), screening evaluation began late 2009, identified Colloidal Dispersion Gel (CDG) as an optimum EOR method for the field.
This paper summarizes Dina CDG project from the laboratory to the field evaluation. Laboratory studies include basic fluid/fluid evaluation, static adsorption, CDG formulations, slimtube, and coreflood tests. Pilot area selection was based on a comprehensive reservoir and injection/production data analysis, water management, well integrity, among other factors. Pilot design was based on detailed numerical simulations using sector and full field models. CDG pilot design also considered water handling limitations and potential injectivity constraints due to the narrow margin of maximum injection and reservoir pressures, combined with low reservoir permeability (50 to 200 mD).
Peripheral CDG pilot included one injector and three producers. CDG injection began in June 2011 and as of September 2012, approximately 437,000 bbl of CDG have been injected (5% of pilot PV). CDG injection strategy considered a fix polymer concentration of 400 ppm and a variable polymer/crosslinker ratio ranging from 40:1 to 80:1; to control maximum injection pressure. Field results showed an important increase in oil recoveries (oil productivity up to 300%) and reduction of water cut decrease (10%). After 16 months, no polymer had been produced in offset producers. Main operating challenges experienced during the pilot project included; the improvement in water quality and its impact on CDG injectivity which will also be described.
This study provides guidance to successfully design, implement, and evaluate CDG pilot projects and other potential chemical EOR technologies in waterflooded reservoirs. Lessons learned during pilot testing contributed to defining pilot expansion strategies supported by an integrated decision-risk management approach.
Miscible/Immiscible carbon dioxide injection is considered as one of the most effective technology to improve oil recovery from complicated formations. Main factor restraining wide application of this technology is its dependence on natural CO2 sources, transportation of CO2, breakthrough of CO2 to production wells, corrosion of well and field equipment, safety and environmental problems etc. However, in-situ carbon dioxide generation technology is eliminating CO2 negative impact and strong control of the process.
The EOR mechanism of proposal technology is described as follows: acid and exothermic chemical reaction function relieve deep reservoir damage, micronucleus systems formed possess abnormal reological properties allowing to improve water flooding efficiency, CO2 as a super-critical fluid decreases oil viscosity and gas form CO2 reaches such place in the formation where not many solvents can enter to, foamed gas-liquid system creates additional resistance for water injected after gas-liquid system, surfactant formed decreases interfacial tension in oil-water contact, and CO2 solved in oil increases oil volume what affects on displacement of residual oil.
Lab research shows that proposed technology can decrease injection pressure of damaged core by 11.7MPa, gas generation amount and oil volume increasing rate increases with temperature and system concentration increasing, oil volume increasing rate and oil viscosity reducing rate increasing with oil viscosity increasing. Under the conditions of 60 degrees Celsius, 10MPa, 2010mPa.s, it can increase oil volume by 25%, reduce oil viscosity by 52.7%, improve recovery efficiency by 7.6%~14.2%.
Field pilot tests were conducted in seven injection wells in China Bohai offshore oilfield in 2009~2010. All the wells present significant effect of decreasing injection pressure and increasing injection rate, average decreasing pressure by 3.2MPa, average increasing injection rate of single well by 22118m3, cumulative increasing injection rate by 154827m3, cumulative increasing oil of around production wells by 29000m3. Field pilot tests shows that proposed technology can be applied in a wide range of geological conditions, and be the key to recovering huge amount of oil from highly watered, depleted, heterogeneous and other type of so called hard-to-recover oil reserves.
The Pelican Lake heavy oil field located in northern Alberta (Canada) has had a remarkable history since its discovery in the early 1970s. Initial production using vertical wells was poor because of the thin (less than 5m) reservoir formation and high oil viscosity (600 to over 40,000cp). The field began to reach its full potential with the introduction of horizontal drilling and was one of the first fields worldwide to be developed with horizontal wells. Still, with primary recovery less than 10% and several billion barrels of oil in place, the prize for EOR is large.
Initially, polymer flooding had not been considered as a viable EOR technology for Pelican Lake due to the high viscosity of the oil, until the idea came of combining it with horizontal wells. A first - unsuccessful - pilot was implemented in 1997 but the lessons drawn from that failure were learnt and a second pilot met with success in 2006. The response to polymer injection in this pilot was excellent, oil rate climbing from 43bopd to over 700bopd and remaining high for over 6 years now; the water-cut has generally remained below 60%.
This paper presents the history of the field then focuses on the polymer flooding aspects. It describes the preparation and results of the two polymer flood pilots as well as the extension of the flood to the rest of the field (currently in progress).
Polymer flooding has generally been applied in light or medium gravity oil and even today, standard industry screening criteria limit its use to viscosities up to 150cp only. Pelican Lake is the first successful application of polymer flooding in much higher viscosity oil (1,000-2,500cp) and as such, it opens a new avenue for the development of heavy oil resources that are not accessible to thermal methods.
Zheng, Frank (Cameron) | Quiroga, Pilar (Cameron) | Zaouk, Moshen (Cameron) | Blackman, Nick (Cameron) | Mandewalkar, Pavan (Cameron) | Sams, Gary W. (Cameron) | Sellman, Erik L (Cameron) | Gopeesingh, Cameron Horace (Cenovus Energy) | Morgan, Justin (Cenovus Energy)
Polymer flood using partially hydrolyzed polyacrylamide (HPAM) has been proven to be an effective method to increase oil recovery. However, when HPAM breaks through the reservoir and shows up in the produced fluids, it brings unique emulsion
characteristics and challenges to the separation processes. Operators have experienced frequent equipment failures on heat exchangers and heating elements. Traditional oil dehydration uses mechanical heater treaters which rely on elevated
temperature to improve the settling of the dispersed water phase. In HPAM flood, the fire tubes in these mechanical heater treaters have become problematic and experienced repetitive failures. Electrostatic technology uses the response to the
electrostatic field by the polar dispersed water phase to enhance the water settling. Electrostatic technology has been a proven technology for oil dehydration and desalting for water flood and other recovery methods such as Steam Assisted Gravity
Drainage (SAGD), but not widely used in HPAM flood. A joint study was conducted between Cameron and Cenovus to evaluate the electrostatic dehydration of the heavy oil from HPAM flood. The results of the study indicate that, due to the presence of HPAM in water, the electrostatic dehydration of the wet oil from HPAM flood demonstrates some unique characteristics. Electrostatic dehydrators can achieve about 300% of the capacity of mechanical heater treaters. Proper equipment and process designs are important to reduce the equipment failures. The results of the study offer a more effective oil dehydration technology to the HPAM flood producers. The benefits of electrostatic dehydration can be especially valuable for the offshore implementation of HPAM flood due to the space and weight savings.
Water-based Enhanced Oil Recovery (EOR) technologies such as Low Salinity Flooding (LSF), Chemical EOR (CEOR), and steam-flooding have been growing in popularity over the years, and are generating new opportunities for the water treatment sector as a result. Water treatment technologies have the unique capability to address equipment and system requirements which are characteristic of EOR projects. However, these technologies typically have little to no history of application in the upstream oil and gas industry. This limited level of experience may impact EOR project budgets and schedules, particularly in offshore applications where weight and footprint availability are of critical value.
In Southeast Asia, two offshore projects are investigating the use of customized water to maximize oil recovery in CEOR applications. In the first project, two CEOR programs consisting of vastly different water quality cocktails are under consideration, one of which incorporates produced water into its water source. In the second project, injection water quality with an ultra-low hardness level is desired, in order to prevent potential precipitation in the reservoir. In both cases, water treatment infrastructure must be capable not only of producing the intended injection water quality, but it must do so consistently in response to potential changes in the quality of the source water used.
This paper describes the results of pilot testing of two typical water treatment technologies, Reverse Osmosis (RO) and unique nanofiltration membranes, to produce a variety of injection water chemistries for CEOR and LSF applications. These applications include ultra-low hardness, high salinity; and low hardness, low salinity injection water. The testing confirms the ability of new water treatment technologies to solve challenging issues that arise in EOR applications, particularly those in offshore applications that must respond to varying needs of reservoirs and footprint/weight limitations.
Zwaan, Marcel (Shell Intl E&P Co) | Hartmans, Robert (PDO) | Saluja, Jasmeet Singh (Shell Intl E&P Co) | Schoofs, Stan (Petroleum Development of Oman) | Rocco, Guillermo (PDO) | Adawi, Rashid (PDO) | Saadi, Faisal (Shell Intl E&P Co) | Lopez, Jorge L. (Shell Global Solutions International) | Ita, Joel (Shell Intl E&P Co) | Mahani, Hassan (Shell Intl E&P BV) | Qiu, Yuan (Petroleum Development of Oman) | Rehling, Johannes
PDO has implemented Enhanced Oil Recovery (EOR) methods including thermal, chemical and miscible gas injection projects in several fields. In the initial phase of these EOR projects, well and reservoir surveillance is key to increase the understanding of the effectiveness of the EOR processes in the various reservoirs. Well-planned and executed reservoir surveillance has proven in the past to add significantly to the production and ultimate recovery from reservoirs.
Because of progress in technology in areas of data acquisition, processing and modeling techniques, well and reservoir surveillance data are increasingly used to optimize EOR processes. However, the interpretation of all data and integration into well and reservoir management workflows is still challenging. This paper describes the ongoing development of workflows for the interpretation, modeling and integration of surveillance data in three EOR projects.
The surveillance methods include geomechanical modeling, thermal reservoir modeling and monitoring through timelapse seismic, surface deformation, microseismic, temperature, pressure and saturation logging.
The Chang-6 reservoir is characterized by low porosity, ultra-low permeability and low Deliverability. At present, water injection pilot only occupied 3.6% of the whole reservoir area. Most of wells will been flooded rapidly once water injection was conducted. How to enhance the oil well production and crude oil recovery is of great strategic significance for guaranteeing the sustained and sTab.le development of YanChang oil field Co.ltd. In this paper, a series of empirical formula was compared and oil recovery of Chang-6 reservoir was determined at 13.9%. The starting pressure gradient and stresssensitive experiments were carried out. The result suggested that the influence of stress-sensitive cannot be ignored. Based on infiltrating fluid experiments and considering the stress sensitivity, a comprehensive research of numerical simulation for the injection zone was conducted to determine the residual oil saturation and demonstrate the feasibility of cyclic water injection, continuous water injection and surfactant injection for EOR. In addition, a suit of clean-fracturing fluid of surfactant acting agent was invented and a foam fluid system was optimized for Chang6 low-permeability reservoir. This study and pilot show that invented clean-fracturing fluid and optimized foam fluid system was effective for ultra-low permeability reservoir.
According to statistics, during the last 10 years of proven IOIP are virgin: permeability less than 50 ! 10-3 µ m2 in 58% of low permeability reservoir. In the new proven IOIP: the proportion of reserves in low permeability up to 70%; Among which heterogeneous reservoirs with low permeability are more than 90%, the cumulative proven reserves are more than 5 billion tons at present.
Yanchang oil filed Was explored and developed the earliest in our country since 1907, "the first well of Chinese Mainland " yan-1 well;the permeability of which is minimum: less than 1.5 ! 10-3 µm2;and the development is extremely difficult; Yanchang oil filed developed slowly. Crude oil production was beyond 1, 000 tons in 1953, rised to the 10, 000 tons in 1959, and to 100, 000 tons in 1984. In 1991, with the accumulation of capital and information opening up, Yanchang oil filed began to introduce water-based gel fracturing, introduction of test volume in 1994, transformation into the success of low-cost in 1995, large scale application in 1996; the average individual well stimulation was 2 to 3 times of the water fracturing sand; crude oil production exceeded 1 million tons in 1997. Since 2000, in order to fully save land costs and protect the environment, cluster well drilling + perforated completion technology was promoted in Yanchang oil filed.
The reservoir permeability is less than 50 ! 10-3µm2 in all the proven IOIP of Yanchang oil filed. The proportion of chang-6 oil reserves whose permeability is less than 1.5 ! 10-3µm2 is up to 67%. For a long time, how to increase oil production and oil recovery has been a major issue which the oil field development facing. Current injection test area only long area of chang-6 low permeability reservoir to 3.6%, the majority of wells are effective quickly after injection, water breakthrough
and flooding fast, the development effect of secondary oil recovery were not significant in the five years.
Faja Petrolifera del Orinoco (F.P.O) is by far the largest known heavy and extra heavy oil accumulation worldwide, located at north of Orinoco river in Venezuela contains about 1300 MMMBN of OOIP and 297 MMMBN of recoverable reserves. Exploitation of FPO has been done until present mainly by cold production, reaching recovery factors, is best cases, of about 10% of OOIP. PDVSA in recent years has conducted studies of quantification and certification of reserves, based on recovery factors that consider EOR projects. In situ combustion, the older member of thermal oil recovery family, is a method with a high thermodynamic efficiency that has allowed reaching recovery factors over 50% in some fields, accomplishing technical and economical success. This work presents a state of the art of combustion process and a review of the reservoir characteristics and field performance of successful applications in Venezuela and the rest of the world. These data were used to establish an application window, without weighting the size or significance of the reservoirs. This window, combined with data from reservoir characterization for the first six blocks of the FPO Junín area, was used to visualize the most prospective areas for the application of the process using parameters of thickness and water saturation in a commercial reservoir characterization software, followed by a qualitative evaluation of pressure, viscosity, temperature and depth, calculating this way the volume of oil and associated areal space occupied. Results obtained define Junín Blocks 5 and 6, specifically in areas of Basal Sands and Oligocene as the ones with the most potential, therefore, detailed studies should be performed to assess the technical and economical feasibility of the process implementation in these areas.
Most exploitation technologies currently and previously applied to heavy oil reservoirs are thermal processes. ??lvarez, C. (2006) states that thermal processes for enhanced recovery of heavy oil have been known and used since the middle of the XX century. According to Turta, A.T. et al (2007), in the last decades, commercial application of in situ combustion has diminished. In Venezuela and Canada, the two countries with the largest accumulations of heavy, extra heavy oil and bitumen worldwide, currently there are no active in situ combustion projects, even when in the past, in both countries were carried out a variety of pilots test for this technology with mixed results. This reduction in the application of in situ combustion has been attributed to operational problems and the lack of control of the process.
The present work focuses in the definition of the reservoir parameters for the application of in situ combustion process, based on the projects that have been successful in the world, and the comparison of those applicability parameters with the characteristics of Junín area of Faja Petrolífera del Orinoco (F.P.O.), with the aim to define potential zones for the successful application of in situ combustion technology. The study was performed with available reservoir description for Junín area of Faja Petrolífera del Orinoco, specifically, Junín 1, Junín 2, Junín 3, Junín 4, Junín 5 and Junín 6 blocks.
Marion, Bruce P. (Schlumberger) | Zhang, Ping (EMI) | Safdar, Muhammad (Schlumberger Middle East SA) | Wilt, Michael (Schlumberger) | Loh, Fabian Fook Hoy (Schlumberger WTA Malaysia S/B) | Nalonnil, Ajay (Schlumberger)
Resolution and measurement diversity are important parameters that help characterize the subsurface and help optimize reservoir management. While traditional well log data provide a variety of high-resolution measurements of the formation very close to the wellbore, surface-based methods provide larger investigation volume but coarser resolution. Crosswell measurements help to bridge the gap by imaging the inter-well space at reservoir scale.
Crosswell seismic data provide high resolution reflection images of reservoir architecture with resolution that is up to 10 times better than that of surface seismic data. Crosswell Electromagnetics (EM) expands the scale investigated by traditional resistivity logging to deliver, a more extensive understanding of fluid distribution and movement at reservoir scale, away from the wells. Not only do these techniques complement each other, but integrating the measured data with conventional logs and surface data into the modeling workflow gives new insight into reservoir structure and fluid movement in the formation.
Recent surveys in various improved recovery projects show that these complementary measurements provide a new way to help subsurface teams accurately image geology and map injection fronts.