Selected abstracts from the upcoming SPE APOGCE are presented below. Register for the conference here: http://www.spe.org/events/en/2016/conference/16apog/registration.html
Optimization of Steamflooding Heavy Oil Reservoirs under Uncertainty. SPE 182190
Cenk Temizel, Aera Energy, Afzal Iqbal, University of Western Australia, Karthik Balaji, Rahul Ranjith, University of Southern California
Conformance improvement is the key to success in most enhanced oil recovery (EOR) processes, especially CO2 foaming or steamflooding. Despite technical and economical restrictions, foam has been used as dispersions of microgas bubbles in the reservoir to help improve mobility. Steam-foam has many applications in the industry, including but not limited to heavy oil reservoirs, which are an important part of the future energy supply. Steam-foam applications have been used to help prevent steam channeling and steam override, thus improving overall sweep efficiency, not only in continuous steam but also in cyclic steam injection processes. Due to the high temperatures achieved during steamfloods, a robust understanding of chemistry including the thermal stability of surfactants is important.
The effectiveness and therefore economics of the steam-foam process are strongly dependent on surfactant adsorption and retention. With that in mind, effective sizing of the foam injected requires a good understanding of the process. In this study, a reservoir simulator is used in which surfactant transport is modeled with surfactant availability determined by a combination of surfactant adsorption, surfactant thermal decomposition, and oil partitioning due to temperature. A robust commercial optimization and uncertainty tool is coupled with the reservoir simulator to generate the scenarios defined by control variables for optimization and uncertainty parameters for sensitivity analysis.
The degree of mobility reduction is interpolated as a product of factors that include aqueous surfactant type and concentration, presence of an oil phase, and the capillary number. An empirical foam modeling approach is employed with foam mobility reduction treated by means of modified gas relative permeability curves. Simulation results including the sensitivity of parameters and controlling agents, providing a better understanding on the influence of surfactant adsorption and thus the amount of chemicals to be used, are presented and discussed to serve as a guide for future applications.It is not easy to find documented examples of realistic optimization studies where significance of each control and uncertainty parameter is outlined and discussed using a realistic reservoir model. The simultaneous use of optimization and uncertainty led to a better understanding and thus control of decision variables in varying ranges of uncertainty that will be useful in analyzing prospective assets.
How to Age Gracefully – Pipeline Life Extension. SPE 182262
Allison Selman, Atteris Pty Ltd Rex Hubbard, Atteris Pty Ltd
This paper presents the engineering process for performing a design life extension study (or design requalification) for an offshore pipeline system. The principles and process however, could be applied to design requalification of any physical asset.
Every pipeline system is designed for a theoretical maximum duration called its design life. In some instances there may be a requirement to continue operations beyond this date. This paper provides guidance on the technical life extension processes and procedures and it focusses on the engineering that is required to provide adequate assurance for safe continued operations.
This paper presents the two main international guidelines that are typically used: NORSOK Y-002 and ISO 12747. The life extension process will be discussed step-by-step with guidance on technical considerations at each stage.
A case study example is used to demonstrate how the process has been applied to assess the fitness for service of an offshore pipeline system for an additional 10 years. The case study describes some of the key engineering assessments which may be required to support the life extension assessment and includes an example of a probabilistic corrosion assessment that enabled deferral of a high cost subsea-to-shore inspection pigging campaign.
Pipeline life extension opens up many development opportunities, especially in challenging economic conditions. If a pipeline can be re-used or re-purposed for future developments then significant CAPEX reductions can be achieved for small, nearby developments. To enable this opportunity the risks of continued operation must be fully understood following a systematic and comprehensive approach to assess the risks. Once the risks are understood then they can be adequately managed through a proactive integrity management program.
The Importance of Collaboration, Integration, and Relational Database Management for Vast Corporate Data: A Case Study in Indonesian National Oil Company. SPE 182299
Nora Desiani, Nur Alam, and Freddy Yulisasongko, Pertamina Hulu Energi, Adeline Susanto, Andrean Satria, and Ade Veria Octora, Halliburton
The asset management of an Indonesia’s national oil company has become complex and challenging because every field acquisition and takeover becomes its new asset (subsidiary). Challenges, such as standard corporate database (e.g. cataloguing), seamless workflow in retrieving massive data, data retention ability, and cartographic reprojection lead to a need for data management optimization and integration, which must be securely and reliably managed.
Smart vision methodology migrates architecture from an existing system to a new integrated system. Workflow consists of steps designed to gather information, engage the customer in a collaborative manner, and assemble opportunities into an orderly plan that has strategic alignment and cost benefit justifications for each case. The approach used by the company refers to professional petroleum data management (PPDM) data model, which puts collaboration, integration, and relational database management forward. Deployment of this model results in standardization of corporate database. Previous different data configurations will then have a standard cataloguing system, which results in consistent data retrieval.
Smart vision methodology is applied to capture and study the company’s existing architecture. A major finding is tremendous data from each of its subsidiary has its own standards and contains structured and unstructured data, which makes it troublesome for analysis to further determine best business decision. History data, data retention, and data permission management are very arduous and implausible. Distortion of cartographic projection data makes the data itself nonscalable. To overcome these challenges, PPDM data model is deployed. Data mapping is performed on 18 the NOC’s subsidiaries’ data. Company preference, policies, and regulations are standardized at corporate level. As a result, an integrated database is being established. Corporate can see all assets in a single project database, which allows further technical analysis and eliminates data duplication problems, making the data manager easy to manage. From user management’s point of view, the presence of the interpreter source priority (ISP) concept allows user collaboration without disrupting either corporate data or other user’s interpretation. Another result is user ability to track historical data. This is important for corporate; thereby, users can access not only interpretations results but also other users’ knowledge content.
The deployment of this model gives ability to manage all the seismic, well, and interpretation-related data into one consolidated project regionally in scalable geographical area and complexity. This allows the company to perform various analytics process related to all data owned by the company.
Improving the Conductivity of Natural Fracture Systems in Conjunction with Hydraulic Fracturing in Stress Sensitive Reservoirs. SPE 182306
Alireza Keshavarz, Ray Johnson, Jr., Themis Carageorgos, Pavel Bedrikovetsky, Alexander Badalyan, Australian School of Petroleum, The University of Adelaide, Adelaide, Australia
The technology of injecting micro-sized proppant particles along with fracturing fluid is proposed to improve the conductivity of naturally fracture systems in stress sensitive reservoirs, by placing graded particles in a larger, preserved stimulated reservoir volume around the induced hydraulic fracture (Fig. 1). One of the main parameters determining the efficiency of the proposed technology is the concentration of placed proppant particles in the fracture systems. A laboratory study has been conducted to evaluate the effect of placed proppant concentration on coal permeability enhancement using injection of micro-sized proppant into coal core and varying effective stress. Permeability values are measured for different concentrations of placed particles as a function of effective stress (Fig. 2). There is an optimum concentration of placed particles for which the cleat system permeability reaches a maximum, further permeability enhancement is more sensitive to concentration of placed proppant at higher than lower effective stress (Fig. 3). The maximum permeability enhancement by 3.2 folds is observed at effective stress of 950 psi.
In a field application, the determination of all cleat apertures to optimize particle sizing will be difficult and unlike the core test, the effluent concentration cannot be derived once the fluid leaves the hydraulic fracture and travels into the cleat or fracture network. In some cases, the distribution and mean values for cleat or natural fracture aperture can be estimated from: physical core observations; imaging tools; and pressure transient tests to derive dual-porosity parameters; from these, a matchstick model for matrix blocks and regular fracture arrangement can be constructed.
In the field, pre-job estimates of fracture leakoff and stimulated reservoir volume can be derived from repeated, increasing pre-frac diagnostic fracture injection test (DFIT) volumes incorporating a hydraulic fracture simulator to derive a volume to leakoff area relationship. We can assume that a larger region of lower aperture leakoff may be beyond the tested region that may be discernable by surface deformation tiltmeter or microseismic monitoring. Thus, volumes and sizing of increasing graded particles could be derived and applied based on the area defined by pre-frac injection testing and the matchstick model derived from reservoir parameters.
In some cases, the fracture apertures cover the spectrum from centimeters to microns and cannot be discerned from near wellbore data. For these instances, a more detailed mathematical model for fractal geometry of the hydraulic fracture and the associated set of induced micro-fractures can be adopted, and the optimal injection schedule becomes one where the injected rate and the injected particle size and concentration are varied as a function of time and volume. The distinguishing feature of this optimized schedule is: the injection of larger particles with lower then higher concentrations over time; the filling of the far-field and thinner cracks first; then, the filling of larger and enlarged fractures nearer to the wellbore. In a similar manner to the first case, this type of model and optimized schedule can be developed using build-up and fall-off injectivity tests to fully characterize the fractal system.