scholarly journals Elastic Property Modeling, Extended Elastic Impedance (EEI) and Curve-Pseudo Elastic Impedance (CPEI) Inversion for Pore Type Analysis and Hydrocarbon Distribution in Carbonate Reservoir, Kujung I Formation, “Humaira” Field, North East Java Basin

2021 ◽  
Vol 873 (1) ◽  
pp. 012028
Author(s):  
I N Kumalasari ◽  
I S Winardhi

Abstract The complexity of the pore shape in carbonate rocks causes the need for a special strategy to characterize carbonate reservoir. The more information used, the more accurate the reservoir characterization will be. Pore type analysis is the important study because it relates to the fluid flow properties. The elastic property modeling show a good match to the actual data. The results of the well log and petrophysical data analysis show that the gas zone is located at the upper side of Kujung I Formation. Based on rock physics modeling result, the possible pore type developing in the Kujung I Formation is reference pore with the dominance of the aspect ratio value of about 0.17-0.19. The carbonate layer containing hydrocarbons is characterized by low Lamda-Rho, Lamda/Mu values and a low Poisson ratio. Porous carbonate layer, characterized by a low Mu-Rho value. The slice results show that the gaseous area is located on the anticline. The zone that has good porosity indicated by low Mu-Rho. In the IN-3 well there are no hydrocarbons, this analysis is in accordance with the geological condition of the IN-3 well which is in a low area on the time structure map. The inversion results show a good match between CPEI against water saturation log and CPEI against porosity log.

1982 ◽  
Vol 22 (05) ◽  
pp. 647-657 ◽  
Author(s):  
J.P. Batycky ◽  
B.B. Maini ◽  
D.B. Fisher

Abstract Miscible gas displacement data obtained from full-diameter carbonate reservoir cores have been fitted to a modified miscible flow dispersion-capacitance model. Starting with earlier approaches, we have synthesized an algorithm that provides rapid and accurate determination of the three parameters included in the model: the dispersion coefficient, the flowing fraction of displaceable volume, and the rate constant for mass transfer between flowing and stagnant volumes. Quality of fit is verified with a finite-difference simulation. The dependencies of the three parameters have been evaluated as functions of the displacement velocity and of the water saturation within four carbonate cores composed of various amounts of matrix, vug, and fracture porosity. Numerical simulation of a composite core made by stacking three of the individual cores has been compared with the experimental data. For comparison, an analysis of Berea sandstone gas displacement also has been provided. Although the sandstone displays a minor dependence of gas recovery on water saturation, we found that the carbonate cores are strongly affected by water content. Such behavior would not be measurable if small carbonate samples that can reflect only matrix properties were used. This study therefore represents a significant assessment of the dispersion-capacitance model for carbonate cores and its ability to reflect changes in pore interconnectivity that accompany water saturation alteration. Introduction Miscible displacement processes are used widely in various aspects of oil recovery. A solvent slug injected into a reservoir can be used to displace miscibly either oil or gas. The necessary slug size is determined by the rate at which deterioration can occur as the slug is Another commonly used miscible process involves addition of a small slug within the injected fluids or gases to determine the nature and extent of inter well communication. The quantity of tracer material used is dictated by analytical detection capabilities and by an understanding of the miscible displacement properties of the reservoir. We can develop such understanding by performing one-dimensional (1D) step-change miscible displacement experiments within the laboratory with selected reservoir core material. The effluent profiles derived from the experiments then are fitted to a suitable mathematical model to express the behavior of each rock type through the use of a relatively small number of parameters. This paper illustrates the efficient application of the three-parameter, dispersion-capacitance model. Its application previously has been limited to use with small homogeneous plugs normally composed of intergranular and intencrystalline porosity, and its suitability for use with cores displaying macroscopic heterogeneity has been questioned. Consequently, in addition to illustrating its use with a homogeneous sandstone, we fit data derived from previously reported full-diameter carbonate cores. As noted earlier, these cores were heterogeneous, and each of them displayed different dual or multiple types of porosity characteristic of vugular and fractured carbonate rocks. Dispersion-Capacitance Model The displacement efficiency of one fluid by a second immiscible fluid within a porous medium depends on the complexity of rock and fluid properties. SPEJ P. 647^


2021 ◽  
Author(s):  
Nasser Faisal Al-Khalifa ◽  
Mohammed Farouk Hassan ◽  
Deepak Joshi ◽  
Asheshwar Tiwary ◽  
Ihsan Taufik Pasaribu ◽  
...  

Abstract The Umm Gudair (UG) Field is a carbonate reservoir of West Kuwait with more than 57 years of production history. The average water cut of the field reached closed to 60 percent due to a long history of production and regulating drawdown in a different part of the field, consequentially undulating the current oil/water contact (COWC). As a result, there is high uncertainty of the current oil/water contact (COWC) that impacts the drilling strategy in the field. The typical approach used to develop the field in the lower part of carbonate is to drill deviated wells to original oil/water contact (OOWC) to know the saturation profile and later cement back up to above the high-water saturation zone and then perforate with standoff. This method has not shown encouraging results, and a high water cut presence remains. An innovative solution is required with a technology that can give a proactive approach while drilling to indicate approaching current oil/water contact and geo-stop drilling to give optimal standoff between the bit and the detected water contact (COWC). Recent development of electromagnetic (EM) look-ahead resistivity technology was considered and first implemented in the Umm Gudair (UG) Field. It is an electromagnetic-based signal that can detect the resistivity features ahead of the bit while drilling and enables proactive decisions to reduce drilling and geological or reservoir risks related to the well placement challenges.


2021 ◽  
Author(s):  
Anthony Lamur ◽  
Silvio De Angelis ◽  
Rayco Marrero ◽  
Yan Lavallée ◽  
Pablo J. Gonzalez

<p>Surface water resources on volcanic islands with moderate rainfall and relatively high permeability are usually scarce or non-existent. As such, life and local economies of these islands mostly relies on groundwater exploitation. It is therefore important to characterise the sustainability of volcanic aquifer systems. In short, an aquifer is deemed in equilibrium when the recharge rate equals or exceeds the exploitation rate. The Izaña area in Tenerife Island (Canary Islands, Spain) has been exploited since the 1900s via a series of ~30 horizontal drilling or water galleries coming from both flanks of the NE-Ridge. Since exploitation began, the water table has dropped continuously, in some area even more than 200 m. Since the 2000s, aquifer dynamics (compaction) have been observed using InSAR indicating a subsidence rate of up to 2 cm per year.</p><p>Here, we investigate a suite of rock samples collected. The samples were collected at several water galleries aiming to be representative of the aquifer materials from the Izaña area. We first characterise the basic physical properties of each samples (porosity, permeability, solid density) before quantifying the elastic parameters (Young’s modulus, Poisson ratio) and uniaxial strength of the lithologies collected. We also measure V<sub>p</sub> under dry and wet conditions (i.e. different saturation levels) to assess whether water saturation can alter the velocity of P-waves passing through those rocks.</p><p>Preliminary results show that connected porosities range from 0.16 to 45%, conferring a wide range of mechanical response to increasing effective pressure, with strength ranging from 18 – 315 MPa and Young’s moduli ranging from 3 – 57 GPa. In a similar fashion, results for V<sub>p</sub> measurements also exhibit a range of values (~1.5 – 4.5 km/s). These data show that materials present in the aquifer are extremely varied, suggesting that both fluid flow and observed deformation are likely to be controlled by the weakest, most porous lithologies.</p><p>These results will further be integrated with the lithostratigraphic record of the aquifer in order to model the mechanical response of the aquifer to changes in effective pressures, and specifically pore pressure reduction with water extraction. Additionally, chemical and textural analysis will provide insights on the evolution of the porous network at different alteration levels, here serving as a proxy for time at saturation in the aquifer. Finally, we aim to compare the experimental results from laboratory measurements to those of hydro-geophysical measurements that will be collected in the field starting in mid-2021.</p>


2018 ◽  
Vol 73 ◽  
pp. 02021
Author(s):  
Fahrudin ◽  
Eka Sainyakit ◽  
Ahmad Syauqi Hidayatillah ◽  
Purnaning Tuwuh Triwigati ◽  
Muhajir

The North East Java Basin is known to be one of the basins that consist of Miocene carbonate rocks, like the reef carbonate of Tuban Formation. It has the potential hydrocarbons that can be explored. Therefore, the FMI log analysis is very important to identify carbonate rocks of Tuban Formation to know facies and characteristics of that carbonate rocks. The method used descriptive and analysis process of FMI and Gamma Ray log to determine facies of the carbonate rock and the system tract. Based on the result of FMI log analysis, there are variations lithofasies include mudstone, wackestone, packstone, grainstone, floatstone, rudstone and claystone. A collection of rock associations can interpret the reef facies. It involves back reef facies, reef core facies, and fore reef facies. The changes of lithofasies and reef facies are caused by sea level fluctuations and subsidence resulting in the system tract. The system tracts generated in the research area include transgressive and highstand system tract.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Reza Kamali ◽  
Azadeh Omidvar ◽  
Ezatallah Kazemzadeh

The aim of geostatistical reservoir characterization is to utilize wide variety of data, in different scales and accuracies, to construct reservoir models which are able to represent geological heterogeneities and also quantifying uncertainties by producing numbers of equiprobable models. Since all geostatistical methods used in estimation of reservoir parameters are inaccurate, modeling of “estimation error” in form of uncertainty analysis is very important. In this paper, the definition of Sequential Gaussian Simulation has been reviewed and construction of stochastic models based on it has been discussed. Subsequently ranking and uncertainty quantification of those stochastically populated equiprobable models and sensitivity study of modeled properties have been presented. Consequently, the application of sensitivity analysis on stochastic models of reservoir horizons, petrophysical properties, and stochastic oil-water contacts, also their effect on reserve, clearly shows any alteration in the reservoir geometry has significant effect on the oil in place. The studied reservoir is located at carbonate sequences of Sarvak Formation, Zagros, Iran; it comprises three layers. The first one which is located beneath the cap rock contains the largest portion of the reserve and other layers just hold little oil. Simulations show that average porosity and water saturation of the reservoir is about 20% and 52%, respectively.


2006 ◽  
Vol 9 (06) ◽  
pp. 681-687 ◽  
Author(s):  
Shawket G. Ghedan ◽  
Bertrand M. Thiebot ◽  
Douglas A. Boyd

Summary Accurately modeling water-saturation variation in transition zones is important to reservoir simulation for predicting recoverable oil and guiding field-development plans. The large transition zone of a heterogeneous Middle East reservoir was challenging to model. Core-calibrated, log-derived water saturations were used to generate saturation-height-function groups for nine reservoir-rock types. To match the large span of log water saturation (Sw) in the transition zone from the free-water level (FWL) to minimum Sw high in the oil column, three saturation-height functions per rock type (RT) were developed, one each for the low-, medium-, and high-porosity range. Though developed on a different scale from the simulation-model cells, the saturation profiles generated are a good statistical match to the wireline-log-interpreted Sw, and bulk volume of water (BVW) and fluid volumetrics agree with the geological model. RT-guided saturation-height functions proved a good method for modeling water saturation in the simulation model. The technique emphasizes the importance of oil/brine capillary pressures measured under reservoir conditions and of collecting an adequate number of Archie saturation and cementation exponents to reduce uncertainties in well-log interpretation. Introduction The heterogeneous carbonate reservoir in this study is composed of both limestone and dolomite layers frequently separated by non-reservoir anhydrite layers (Ghedan et al. 2002). Because of its heterogeneity, this reservoir, like other carbonate reservoirs, contains long saturation-transition zones of significant sizes. Transition zones are conventionally defined as that part of the reservoir between the FWL and the level at which water saturation reaches a minimum near-constant (irreducible water saturation, Swirr) high in the reservoir (Masalmeh 2000). For the purpose of this paper, however, we define transition zones as those parts of the reservoir between the FWL and the dry-oil limit (DOL), where both water and oil are mobile irrespective of the saturation level. Both water and oil are mobile in the transition zone, while only oil is mobile above the transition zone. By either definition, the oil/water transition zone contains a sizable part of this field's oil in place. Predicting the amount of recoverable oil in a transition zone through simulation depends on (among other things) the distribution of initial oil saturation as a function of depth as well as the mobility of the oil in these zones (Masalmeh 2000). Therefore, the characterization of transition zones in terms of original water and oil distribution has a potentially large effect on reservoir recoverable reserves and, in turn, reservoir economics.


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