Ninth international geostatistics congress, oslo, norway june 11 15, 2012 uncertainty study on inplace volumes in statoil kjersti b. Barton smeal college of business administration the pennsylvania state university 406 business building university park, pa 16802, usa barry l. Uncertainty analysis of thermocouple measurements used in. Uncertainty can be modeled, but there is no objective measure of uncertainty.
Other example from the western desert presented the effect of geological uncertainty on stoiip calculations of the cretaceous kharita reservoir. Uncertainty analysis of thermocouple measurements 10 1 executive summary an uncertainty analysis was performed on several data acquisition systems dass that use type k chromelalumel thermocouples tcs. A framework for input uncertainty analysis russell r. Since all geostatistical methods used in estimation of reservoir parameters are inaccurate, modeling of estimation error in form of uncertainty analysis is very important. Uncertainty study on inplace volumes in statoil ninth. Tornado diagram illustrating the uncertainties affecting the ur. Conceptual basis for uncertainty analysis annex 1 a1. Examples are presented in which uncertainty analysis was utilized or is needed to gain further knowledge of a particular measurement process and to characterize final results. A geological uncertainty study was initiated to identify and quantify the input parameters of. To better understand reserves estimation, a few important terms require definition. This extremely wide range of reserves reflects high geological uncertainty. Approaches for performing uncertainty analysis in largescale. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
Guidelines on uncertainty analysis in exposure assessment. Guidelines for the evaluation of petroleum reserves and. After the stages described above, 100 realizations of complete model were generated by varying seed number alone. This course learning contents are design to provide the reservoir engineers with the concepts and necessary application skills for uncertainty assessment quantification and optimizations using. Neumann1, bjorn kare hegstad2, elisabeth bratli3, inger kloster osmundsen4. The significance of the standard deviation is this. Risk and uncertainty can be related at times, however sometimes uncertainty carries no material risk. Uncertainty analysis now we will use what we learned in chap. Approaches for performing uncertainty analysis in largescale energyeconomic policy models antje kann and john p. An uncertainty analysis gives us the support we need for decisions about milestones in the plan and buffers to protect against the impact of variability. Estimating resource and reserves crosses the disciplines between geoscientists and petroleum engineers. The highest ranked contributors to uncertainty in stock tank oil initially in place stoiip were oil water. The stoiipuncertainty for a given segment in a given zone is modeled as where grv, ewell.
Stoiip validation for a heterogeneous multilayered. The true value of a quantity is related to the mean of several measurements by. Example of judy creek reef complex in swan hills, alberta, canada article pdf available in aapg memoir december 2011. Uncertainty calculator standard operating procedure required by estimating type i and type ii errors. It is common practice within oil companies to use expectation curves to express ranges of uncertainty. This array of variability presents a significant challenge in assessing the viability of recovering hydrocarbon. Decline curve analysis for estimating eurs and ooips. Mcmichael over the past 60 years, numerous technical organizations, regulatory bodies, and financial. Constraining uncertainty in static reservoir modeling. Coupling spatial and frequency uncertainty analyses in reservoir modeling. Decline curve analysis three basic decline curve equations. Guidelines for the evaluation of petroleum reserves and resources. In this study, drive index 8 helped defining the most effective parameters to constraint uncertainty in production and pressure.
Remember that errors can be divided into two categories, bias and precision errors. Risk infers that there is some material implication in the outcome. The uncertainty associated with each parameter may be expressed in terms of a probability density function pdf, and these may be combined to create a pdf for stoiip. Sensitivity analysis of input parameters shows a decreasing order effect on reserve estimate from thickness, area, porosity, water saturation and formation volume factor for first and second simulation analysis respectively keywords. Abstract this presentation focuses on a field case where the statoil standard workflow for estimating the uncertainty in inplace volumes is used. A methodology is presented for uncertainty estimation in volumetrics. Petrel uncertainty analysis and optimization fundamental. As production continues, the accuracy and reliability of the estimates obtained from rta, material balance, and decline analysis increases. Certain biological tests, spot tests, and immunoassay tests are included in this category. Original oil in place ooip original oil in place and original gas in place ogip original gas in place refer to the total volume of hydrocarbon stored in a reservoir prior to production. Pdf uncertainty analysis encompasses the quantification and. Project planning, uncertainty analysis and critical chain. While the geoscientist may well have primary responsibility, the engineer must carry the resource and reserve models forward for planning and economics.
Monthly production volumes provide the data for material balance and decline analysis techniques. Chapter 6 petroleum economics uncertainty and risk. Across the breadth of hydrocarbon exploitation there is uncertainty from acquisition, analysis, application, technology, and economics, all the way to timing and resources. Stoiip validation for a heterogeneous multilayered reservoir. Principles and applications of measurement uncertainty. Quantifying uncertainty differs for single measurements versus sample means. Weyant energy modeling forum, stanford university terman engineering building, room 406 stanford, ca 94305 emf working paper 14.
Quantifying uncertainty, oil reserves estimate, stochastic, techniques. Stoiip were estimated at 12, 25 and 95 million tons for 1p, 2p and 3p categorizes respectively. Uncertainty analysis addresses fidelity and is used in different phases of an experiment, from initial planning to final reporting attention is needed to ensure uncertainties do not invalidate your efforts in propagating uncorrelated errors from individual measurement to final result, use the square root of the sums of the squares. Petrel uncertainty analysis and optimization fundamental subsurface uncertainties assessment is an essential phase in any field development strategy. Our main concern is the impact uncertainty has on petroleum investment. We will study uncertainty analysis for the following measurement situations. Random uncertainty for a sample mean is estimated from the standard deviation, scaled by the tdistribution and the sample size. A comparison of the deterministic and probabilistic methods, however, can. Evaluating uncertainty in the volumes of fluids in place in an. Alternatively where multitank dynamic stoiip is higher than the volumetric stoiip for one or more of the history matched hydraulic flow units, a probable reservoir extension is viable and both geologic intuition and engineering skills should be exercised to outline such extension. Uncertainty study on inplace volumes in statoil kjersti b. The relationship between pdfs and expectation curves is a simple one. Facies interpretation and modelling an integrated workflow. How to apply the monte carlo simulation principles to a game of dice using microsoft excel.
Rf stoiip 1100 1600 2100 2600 3100 3600 ur mmstb figure 6. In the following gives an example by use of microsoft project and a special data program for planning under uncertainty. Guidelines for the evaluation of petroleum reserves and resources 1 chapter 1 summary introduction claude l. Uncertainty assessment in 3d reservoir modeling an integrated approach uncertainty is not an inherent feature of our reservoirs. New approaches to geological uncertainties in stoiip. Systematic or bias b uncertainty is the same in both cases, but random or precision p uncertainty is reduced by increased sample size. From the well data and background knowledge, the probability density functions pdfs. Uncertainty estimation in volumetrics for supporting. Pdf coupling spatial and frequency uncertainty analyses. Calculating oil in place by the volumetric method oil in place by the volumetric method is given by. These measurements are made in typical experiments performed. During the asset life cycle more data is obtained in order to do technical analysis to provide.
Mcmichael over the past 60 years, numerous technical organizations, regulatory bodies, and. In this first iteration parameters were ranked by stoiip and p90, p50 and p10 cases picked as low, base. Stoiip validation for a heterogeneous multilayered reservoir of a. Figure 61 tornado diagram illustrating the uncertainties. World academy of science, engineering and technology. Integrating all the techniques provides more reliable answers than relying solely on any.
The uncertainties included in the uncertainty analysis of inplace volumes are. In statoil there is a requirement to undertake a thorough uncertainty analysis before making an. Pdf coupling spatial and frequency uncertainty analyses in. Index termsuncertainty in scheduling, stochastic time. Mehdi behnamrad, behnam jan ahmad, geostatic modeler.