The success story of Windalia waterflood optimisation through integrated asset management in a mature field

2011 ◽  
Vol 51 (2) ◽  
pp. 726
Author(s):  
Lina Hartanto ◽  
Wisnu Widjanarko ◽  
Diala Muna

Australia’s Barrow Island Windalia reservoir—the nation’s largest onshore waterflood—was developed in the late 1960s. The Barrow Island oilfield is Chevron Australia’s only mature waterflood, comprising more than 220 active injectors. The injectors pressurise and increase oil recovery from the geologically complex, low-permeable and heterogeneous Windalia Sand Member. To date it is estimated that the value of waterflooding has effectively reduced the field decline rate from approximately 18 % per annum to less than 2 %—adding millions of barrels in recovery and years on to productive field life. In September of 2008, the Windalia Waterflood achieved full field restitution. This involved the replacement and commissioning of glass-reinforced epoxy injection flow lines, a ring-main network and produced water re-injection facilities. Significant challenges were overcome in the process of realising the restitution’s full potential. Several waterflood optimisation activities have now been executed to achieve oil uplift and to capitalise on Chevron Australia’s investment. Compounded with restitution, the activities have successfully achieved the asset objective of arresting field production decline. This paper highlights the challenges encountered by the waterflood team, providing insights and lessons learned in the dynamic and holistic nature of waterflood management. It also highlights the interplay of considerations and what is crucial to achieving optimum sweep efficiency and pressurisation.

2021 ◽  
Author(s):  
Bogdan-George Davidescu ◽  
Mathias Bayerl ◽  
Christoph Puls ◽  
Torsten Clemens

Abstract Enhanced Oil Recovery pilot testing aims at reducing uncertainty ranges for parameters and determining operating conditions which improve the economics of full-field deployment. In the 8.TH and 9.TH reservoirs of the Matzen field, different well configurations were tested, vertical versus horizontal injection and production wells. The use of vertical or horizontal wells depends on costs and reservoir performance which is challenging to assess. Water cut, polymer back-production and pressures are used to understand reservoir behaviour and incremental oil production, however, these data do not reveal insights about changes in reservoir connectivity owing to polymer injection. Here, we used consecutive tracer tests prior and during polymer injection as well as water composition to elucidate the impact of various well configurations on sweep efficiency improvements. The results show that vertical well configuration for polymer injection and production leads to substantial acceleration along flow paths but less swept volume. Polymer injection does not only change the flow paths as can be seen from the different allocation factors before and after polymer injection but also the connected flow paths as indicated by a change in the skewness of the breakthrough tracer curves. For horizontal wells, the data shows that in addition to acceleration, the connected pore volume after polymer injection is substantially increased. This indicates that the sweep efficiency is improved for horizontal well configurations after polymer injection. The methodology leads to a quantitative assessment of the reservoir effects using different well configurations. These effects depend on the reservoir architecture impacting the changes in sweep efficiency by polymer injection. Consecutive tracer tests are an important source of information to determine which well configuration to be used in full-field implementation of polymer Enhanced Oil Recovery.


2004 ◽  
Author(s):  
B.N. Ghosh ◽  
Soma. D. Sarkar ◽  
J.P. Lohiya ◽  
T.K. Das

2016 ◽  
Vol 19 (04) ◽  
pp. 655-663 ◽  
Author(s):  
Torsten Clemens ◽  
Markus Lüftenegger ◽  
Ajana Laoroongroj ◽  
Rainer Kadnar ◽  
Christoph Puls

Summary Polymer-injection pilot projects aim at reducing the uncertainty and risk of full-field polymer-flood implementation. The interpretation of polymer-pilot projects is challenging because of the complexity of the process and fluids moving out of the polymer-pilot area. The interpretation is increasingly more complicated with the heterogeneity of the reservoir. In the polymer pilot performed in the 8 Torton Horizon (TH) reservoir of the Matzen field in Austria, a polymer-injection well surrounded by a number of production wells was selected. A tracer was injected 1 week before polymer injection. The tracer showed that the flow field in the reservoir was dramatically modified with increasing amounts of polymer injected. Despite short breakthrough times of 4 to 10 weeks observed for the tracer, polymer breakthrough occurred only after more than 12 months although injection and production rates were not substantially changed. The tracer signal indicated that the reservoir is heterogeneous, with high flow velocities occurring along a number of flow paths with a limited volume that are strongly connecting the injection and production wells. By injecting polymers, the mobility of the polymer-augmented water was reduced compared with water injection, and led to flow diversion into adjacent layers. The tracer response showed that the speed of the tracer moving from injection to production wells was reduced with increasing amount of polymer injected. This response was used to assess the changes of the amount of water flowing from the injection well to production wells. After a match for the tracer curve was obtained, adsorption, residual resistance factor (RRF), and dispersivity were calculated. The results showed that, even for heterogeneous reservoirs without good conformance of the pilot, the critical parameters for polymer-injection projects can be assessed by analyzing tracer and polymer response. These parameters are required to determine whether implementation of polymer injection at field scale is economically attractive. Along the flow path that is connecting injection and production well, as shown by the tracer response, an incremental recovery of approximately 8% was achieved. The polymer retention and inaccessible pore volume (IPV) in the reservoir were in the same range as in corefloods. Incremental oil recovery caused by acceleration along the flow path was estimated at approximately 20% of the overall incremental oil production caused by polymer injection and 80% was attributed to improved sweep efficiency.


Author(s):  
Marcelo F. Zampieri ◽  
Rosangela B. Z. L. Moreno

Developing an efficient methodology for oil recovery is extremely important in this commodity industry, which may indeed lead to wide spread profitability. In the conventional water injection method, oil displacement occurs by mechanical behavior between fluids. Nevertheless, depending on mobility ratio, a huge quantity of injected water is necessary. Polymer injection aims to increase water viscosity and improve the water/oil mobility ratio, thus improving sweep efficiency. The alternating banks of polymer and water injection appear as an option for the suitable fields. By doing so, the bank serves as an economic alternative, as injecting polymer solution is an expensive process. The main objective of this study is to analyze and comparison of the efficiency of water injection, polymer injection and polymer alternate water injection. For this purpose, tests were carried out offset in core samples of sandstones using paraffin oil, saline solution and polymer and were obtained the recovery factor and water-oil ratio for each method. The obtained results for the continuous polymer injection and alternating polymer and water injection were promising in relation to the conventional water injection, aiming to anticipate the oil production and to improve the water management with the reduction of injected and produced water volumes.


2021 ◽  
Author(s):  
Mohamad Yousef Alklih ◽  
Nidhal Mohamed Aljneibi ◽  
Karem Alejandra Khan ◽  
Melike Dilsiz

Abstract Miscible HC-WAG injection is a globally implemented EOR method and seems robust in so many cases. Some of the largest HC-WAG projects are found in major carbonate oil reservoirs in the Middle-East, with miscibility being the first measure to expect the success of a HC-WAG injection. Yet, several miscible injection projects reported disappointing outcomes and challenging implementation that reduces the economic attractiveness of the miscible processes. To date, there are still some arguments on the interpretation of laboratory and field data and predictive modeling. For a miscible flood, to be an efficient process for a given reservoir, several conditions must be satisfied; given that the incremental oil recovery is largely dependent on reservoir properties and fluid characteristic. Experiences gained from a miscible rich HC-WAG project in Abu Dhabi, implemented since 2006, indicate that an incremental recovery of 10% of the original oil in place can be achieved, compared to water flooding. However, experiences also show that several complexities are being faced, including but not limited to, issues of water injectivity in the mixed wettability nature of the reservoir, achieving miscibility conditions full field, maintaining VRR and corresponding flow behavior, suitability of monitoring strategy, UTC optimization efforts by gas curtailment and most importantly challenges of modeling the miscibility behavior across the reservoir. A number of mitigation plans and actions are put in place to chase the positive impacts of enhanced oil recovery by HC-WAG injection. If gas injection is controlled for gravity and dissolution along with proper understanding on the limitations of WAG, then miscible flood will lead to excellent results in the field. The low frequency of certain reservoir monitoring activities, hence less available data for assessment and modeling, can severely bound the benefits of HC-WAG and make it more difficult to justify the injection of gas, particularly in those days when domestic gas market arises. This work aims to discuss the lessons learned from the ongoing development of HC-WAG and attempts to comprehend miscible flood assessment methods.


2009 ◽  
Vol 49 (1) ◽  
pp. 453
Author(s):  
Pavel Bedrikovetsky ◽  
Mohammad Afiq ab Wahab ◽  
Gladys Chang ◽  
Antonio Luiz Serra de Souza ◽  
Claudio Alves Furtado

Injectivity formation damage with water-flooding using sea/produced water has been widely reported in the North Sea, the Gulf of Mexico and the Campos Basin in Brazil. The damage is due to the capture of solid/liquid particles by the rock with consequent permeability decline; it is also due to the formation of a low permeable external filter cake. Yet, moderate injectivity decline is not too damaging with long horizontal injectors where the initial injectivity is high. In this case, injection of raw or poorly treated water would save money on water treatment, which is not only cumbersome but also an expensive procedure in offshore projects. In this paper we investigate the effects of injected water quality on waterflooding using horizontal wells. It was found that induced injectivity damage results in increased sweep efficiency. The explanation of the phenomenon is as follows: injectivity rate is distributed along a horizontal well non-uniformly; water advances faster from higher rate intervals resulting in early breakthrough; the retained particles plug mostly the high permeability channels and homogenise the injectivity profile along the well. An analytical model for injectivity decline accounting for particle capture and a low permeable external filter cake formation has been implemented into the Eclipse 100 reservoir simulator. It is shown that sweep efficiency in a heterogeneous formation can increase by up to 5% after one pore volume injected, compared to clean water injection.


2021 ◽  
Vol 11 (2) ◽  
pp. 949-959 ◽  
Author(s):  
Nasser Alizadeh ◽  
Ben Salek

AbstractThis paper presents an approach to optimize the recovery factor and sweep efficiency in a waterflooding process by automating the optimum injection rate calculations for water injectors using streamline simulation. A streamline simulator is an appropriate tool for modern waterflood management and can be used to determine the dynamic interaction between injector and producer pairs, which will vary over time based on sweep efficiency and operational changes. A streamline simulator can be used to identify injectors, which are not supporting production and contributing mainly to water producing wells. Streamlines illustrate natural fluid-flow paths in the reservoir, which are based on fluid properties, rock properties, well distribution and well rates across the reservoir. A bundle of connected streamlines can provide the oil in place between an injector/producer pair at any given time during a simulation run. Thus, the well pair recovery factors for each injector/producer pair, the produced water cut and the weighting factor for each injector are determined. Multiplying this weighting factor by the injection rates determines the new injection rate for each injector. For a well pair water cut that is lower than the average field water cut, the injection rate will be increased and vice versa. Given a finite volume of injection water, there will be a re-allocating of water from a well pair with a low recovery factor and high water cut and redistributing the water to injectors supporting low water cut producers, thus maximizing the recovery factor and reducing the field water production. The described approach is an automated procedure during the reservoir simulation run, making it appropriate for full field waterflood optimization with many injectors and producers in high-resolution heterogeneous brown reservoirs. This approach can reduce the water cut and increase the recovery factor and extend the life of the waterflooded oil fields. It was initially tested with a synthetic model and later with an actual reservoir model, which will be described in this paper.


2021 ◽  
Author(s):  
Artem Galimzyanov ◽  
Konstantin Naydensky ◽  
Olaf Kristoffer Huseby

Abstract Justified application of enhanced oil recovery (EOR) methods is one of the key tasks of oil operating companies for the effective development of not only brown oil fields at a mature stage of production, but also for green fields. The selection and justification of one or another method of enhanced oil recovery for certain geological conditions often requires not only looking for worldwide experience, conducting laboratory tests on a core, but also performing pilot tests at a polygon area. The subsequent full-field implementation of EOR method requires confirmation of its effectiveness based on the increase in oil recovery factor. This article describes both the experience of using interwell tracer studies to substantiate the effectiveness of EOR technologies in pilot areas, and the experience of evaluating the effectiveness of EOR technologies with full-field implementation in various fields. The work carried out on the integrated use of tracer studies makes it possible to apply a scientific and engineering approach to the selection of an enhanced oil recovery method by assessing the sweep efficiency before and after the application of the EOR technology. Examples of the use of this integrated approach for different oil fields are given. The presented technologies and experience of the work performed will significantly speed up the choice of the EOR technology for certain geological conditions and verify the effectiveness of the selected EOR method.


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