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This paper discusses findings of sedimentary features observed from deepwater outcrops in Northwest Sabah. The observations were based on 7 outcrop localities of Lower Oligocene – Upper Oligocene sections around Klias and Kudat Peninsulas, and Kota Kinabalu, covering Temburong, Belait, West Crocker, and Kudat formations. Temburong Formation (Lower Oligocene-Lower Miocene) was observed at Menumbok (Stop 1) and Tanjung Aru (Stop 2). It comprises interbedded shale and sandstone turbidite sequence representing deposition in deepwater setting. At Batu Luang (Stop 3) the deepwater turbidite Temburong Formation is observed overlain unconformably by stacked fluvial channel deposits of Belait Formation (Middle to Upper Miocene). Here, the overlying fluvial deposits comprise predominantly conglomerates which are believed to represent basal Belait Formation lies over regional unconformable surface correlatatable to Deep Regional Unconformity (DRU). Deepwater West Crocker Formation (Lower Oligocene-Lower Miocene) was observed at King Fisher-Sulaman, Kota Kinabalu (Stop 4), composed of predominantly thick sandstone interbedded with shale. Meanwhile, Sikuati Member of the Kudat Formation (Lower Miocene) was observed at Pantai Sikuati (Stop 5) and Bukit ‘V’ (Stop 6) outcrops. It consists of interbedded sandstone and shale of turbidite successions. At Tanjung Simpang Mengayau (Stop 7) thick sandstone interbedded with thin shales of Kudat Formation was observed. In general, the Temburong Formation at Stops 1 and 2 show Bouma sequence of Ta-Tb-Te successions, but relatively thicker Te at Stop 1 suggesting a prolonged mud suspension deposit compared to Stop 2. At Stop 3, the deepwater Temburong Formation was subjected to a substantial tectonic uplift and massive erosion associated with DRU. Further northwards at Stop 4 West Crocker Formation exhibits thicker Ta successions which implies deposition within a slightly higher energy regime as compared to that of Temburong Formation at Stop 3. Meanwhile, at Stops 5 and 6 different depositional energy levels are shown in the lower and upper stratigraphic intervals. In the lower interval deposition took place within a higher energy condition as shown by thick Ta. It was followed by gradual decreasing depositional energy regime in the upper interval as shown by predominance Tc-Td-Te. Meanwhile, at Stop 7 a thick massive graded sandstone overlain by thin mudstone bed was observed which implies a prolonged Ta succession followed by short-term Te of mud suspension deposits.

In Low resistivity low contrast (LRLC), also known as low resistivity pay (LRP), one of the factors is, the existence of alternating thin sedimentary layers of various rock types in hydrocarbon reservoirs, commonly consist of sandstone, siltstone and claystone and have been widely reported today. This phenomenon causes the potential intervals to be misinterpreted as non-hydrocarbon bearing zone due to its ability to reduce the measured apparent resistivity which result in overestimated water saturation calculation and due to its low contrast, in comparison with water bearing interval, this phenomenon always make well analyst to by passed this interval. As a result, from falsified measured resistivity, the final reserves volume tends to be underestimated. A huge number of studies have proven this kind of interval able to produce oil with very low water-cut therefore this paper would like to present the case study of solving this complex lithology by using sophisticated petrophysical modeling with a combination of Thomas-Stieber plot. Measured vertical (Rv) and horizontal (Rh) resistivity is available for this study and will be used as comparison. In general, this paper will present two case studies for final saturation computation, a) The sand resistivity will be estimated through inversion using measured resistivity anisotropy (Rv - Rh), b) The sand resistivity is reconstruct based on identified volume fraction of clay, whereas the shale resistivity estimated from conventional resistivity (RDEEP). Both of the cases will be calibrated using measured saturation from core by using Dean-Stark technique. Selected interval in this study (X1 zone) is a proven oil interval with a standard volume production rate 698 bbl/day. The final comparison of saturation computed using measured resistivity anisotropy yield a high correlation in contrast, the inversion using conventional resistivity yields less correlation with saturation from core. Nonetheless, by comparing with conventional computed saturation i.e. Waxman Smith, the final saturation of these two cases is significantly increased and unmasked the hydrocarbon-bearing interval. Therefore, case b indicates the best approach to be used whenever the advance measured resistivity anisotropy is unavailable.

In the framework of a $${{\hbox {CO}}}_{2}$$ storage feasibility study, we evaluate porosity and permeability of shale formations constituting the overburden of a hydrocarbon reservoir, where the gas is stored. These properties are required to perform fluid-flow simulations and analyze possible leakages from the reservoir to the surface. In this process, calibration with well logs is essential. Standard log-interpretation procedures on shales may induce errors, since the shale part is discarded due to its apparent negligible permeability compared to the clastic part. In this study, it is the “shale effect” that we consider by introducing its contribution to porosity and therefore to permeability, so that new expressions are developed to obtain porosity from density and traveltimes that consider this effect. Indeed, shales have non-zero porosity and finite permeability even if the flow rates are several orders of magnitude smaller than those in sandstones. Moreover, calibration does not mean to honour one single log profile but the interpretation should be compatible with all the profiles available. We obtain clay content, porosity and permeability from two wells offshore Malaysia using the linear and Stieber relations between gamma ray and shale volume. The results of using these relations are quite similar. However, the analysis shows that the density logs yield too small values of porosity. Instead, the sonic log gives a better estimate of porosity that honours the P-wave velocity. The verification is performed by using the Krief–Gassmann equations to obtain the P-wave velocity, either from the density-log or from sonic-log derived porosities. This is also confirmed by comparison to porosity obtained from the neutron log.

The Transient Electro-Magnetic (TEM) geophysical technique was deployed to map and characterized the subsurface of Pahang River Basin along the East Coast Peninsula Malaysia. The data aimed at differentiating between the massive zones and the weak zones within the region, to also assess and differentiate the subsurface structures and comes up with recommendations for policy decision, formulation and plans on the flooding impact, surface water and groundwater managements, in addition to other environmental related issues ravaging the area. The data presented in this paper, showed the properties of the subsurface rocks underlain the region as beneficial to the Agriculturists; Climatologists; Engineers; Environmentalists; Geoscientists, Hydrologists and Policy formulation officers. The TEM data collection utilized a 100 m x 100 m single loop coil for both the Transmitter (Tx) loop and the Receiver (Rx) loop to produce a total surface area coverage of 10,000 m2 per survey line along a single profile. The total area covered in the data extended across an average area of 30 km x 40 km in parts of Maran, Temerloh and Jerantut districts, within the State of Pahang, East Coast, Peninsula Malaysia. The conductivity data recorded varied from -20 mS/m to about 440 mS/m at a maximum depth of about 375 m. On the other hand, the resistivity data recorded varied from 0 Oh-m to about 1000 Oh-m. The information derived from the data are intended for potential abstraction by the Malaysian Groundwater Management Board; the Department of Mineral and Geoscience; Department of Irrigation and Drainage; the Pahang State Water Board, and the Department of Agriculture.

Bottom simulation reflectors (BSR) are seismic events generally corresponding to a partially saturated layer with gas separating hydrate-bearing sediments from brine-saturated sediments. Seismic attenuation and velocity dispersion affects the waveform of the BSR event. In this work, we consider a 1D methodology to study the effects of seismic Q , velocity dispersion, layer thickness and properties and characteristics of the overburden on the reflection coefficients and waveform of such event. We describe the media by using a rock-physics model based on poroelasticity, calculate the reflection coefficient of the BSR layer of varying thickness and compute the waveforms with a full-wave pseudospectral method. The proposed rock-physics/modeling methodology is fast in terms of computer requirements and can be used to quantify the seismic properties and compute waveforms useful for seismic interpretation and inversion of quantities such as porosity, hydrate content, gas saturation, clay content and thickness of the BSR layer. We show that in many cases the interpretation can be counterintuitive and a proper rock-physics methodology is essential to reach valid conclusions about the influence of the different parameters on the wave properties.

The classical Earth model used to process seismic data assumes plane layers and a velocity analysis based on a hyperbolic approximation of the reflection events, where basically one parameter (the stacking velocity) is used to perform the normal move-out (NMO) correction to obtain the stacked section. We explore the possibility of using alternative approaches, other than the standard Dix equation based on the root-mean-square (RMS) velocities, to obtain the interval velocities and perform the depth conversion in order to locate the interfaces. Specifically, we consider traveltime equations as a function of offset using different NMO approximations, based on the average, RMS and root-mean-quartic (RMQ) velocities. A generalised form of Dix's equation is used for this purpose. Moreover, we analyse the model-dependency of the different NMO equations. We consider a simple 4-layer model and a model based on data from the Cooper basin, South Australia, to test the NMO equations. We build an elastic-velocity model and compute a common midpoint (CMP) synthetic seismogram. The reflection events are identified and traveltimes are picked to perform a non-linear inversion with the conventional (one parameter) hyperbolic approximation, the 3-term Taner and Koehler equation and approximations based on the average, RMQ and RMS velocities, also using two parameters. The model has a velocity inversion which poses a challenge to the approximations. The performance of the approximations is model dependent, so a-priori information of the velocity profile can be useful to perform a suitable inversion, or an optimal stack of the reflection events is required to test the NMO correction. Moreover, the results show that the inversion based on the RMS velocities yields better results than those based on the RMQ velocities, but this is not always the case. On the other hand, the inversion using the average velocity performs a worse velocity–depth estimation, even compared to the RMS results from the hyperbolic approximation.

Surface conductivity is indicated by electrical resistivity dispersion in low water saturation. When evaluating surface conductivity, the pore geometry should be considered because a large structure is easier to saturate rather than a small structure. This work underlines the evaluation of pore geometry distribution and saturation degree of reservoir rock and its effect to electrical dispersion. It is found that pore radius distribution and porosity has a good correlation with electrical dispersion. The large structure reflects more electrical dispersion compare to the small one. In high water salinity, surface conductivity occurs at low water saturation degree and vanishes with more water saturation addition. The potential indicator to estimate rock porosity derived from electrical dispersion has been verified in this article.

Thin and relatively thin anelastic layers (compared to the signal wavelength) generally represent hydrocarbon reservoirs, where the rock is a sandstone or a source rock saturated with brine, oil and gas. The study of the seismic response of these layers is important to detect the hydrocarbons on the basis of the reflection and transmission coefficients and the wave velocity and attenuation properties. Different seismic experiments (source-receiver configurations) can provide useful information to characterise its properties. In this work, we consider varying thicknesses and Q values of the layer and analyse the reflection and transmission coefficients. Moreover, we obtain spectrograms of surface seismic profiles and vertical and horizontal well profiles (VSP and HSP, respectively) to analyse their frequency content with offset due to variations of the attenuation properties of the layer. In addition, we compare the effects due to NMO stretching and intrinsic attenuation related to the low-frequency shadows (LFS) observed in real data after stacking, since LFS can have several causes. Ambiguity is present in this case, indicating that non-stretch NMO is required, otherwise an offset mute of the data may remove useful information regarding the intrinsic (physical) loss.

The electrical evaluation of reservoir rock needs to deem several factors that really describe a subsurface condition. As confining pressure can cause either pore space of the rock to collapse or rock properties to change, a detailed identification towards the extent of the pressure and water saturation effect on electrical properties is needed. This work is mainly focused on the investigations of electrical properties on shaly sandstones, encompassing the effects of pore geometries, confining pressure, and partial water saturation on electrical properties. Here, the frequency of electrical measurement is between 1 Hz and 0.2 MHz. It is indicated that an interfacial and geometry change due to pressure is easily recognized by imaginary resistivity in low water saturation, reflecting that confining pressure will affect only small defect to pore geometry. Meanwhile in high water saturation, bulk volume conductivity is more dominant, thus making interfacial contribution negligible. From petrographic analysis of this work it is found that only pore radius distribution has a good relationship with electrical dispersion. The relaxation time and its distribution are estimated by simultaneous inversion of real and imaginary resistivity. The Cole-Cole model inversion is applied to obtain these parameters. For this purpose, the integration of Lavenberg-Marquardt and Singular Value decomposition (SVD) are used in order to avoid singularity problems. The obtainment of decreasing of relaxation time with the increasing of confining pressure reflects the reduction of the internal surface area.

Pressure and saturation are of two important parameters to be considered to evaluate the electrical properties of reservoir rock. As confining pressure can cause pore space of rock to collapse as well as rock properties to change, it for some reason is necessary to examine the degree of the pressure and saturation changes in affecting the electrical properties in detail. This work mainly focuses on the investigations of electrical properties of sandstones and carbonates. The effects of pore geometries, confining pressure, and partial water saturation on electrical properties are investigated. The new electrical dispersion models from 0.01 Hz until 0.2 MHz for shaly sandstone are also developed. Petrographic image analysis is carried out to asses pore geometry of media. Circularity, gamma, pore aspect ratio, pore size distribution and pore angle distribution are calculated to evaluate their effect on electrical dispersion. An observation on confining pressure and water saturation is then evaluated to obtain their impact on pore structure and complex resistivity. The result of this work, indicated by electrical resistivity dispersion in low water saturation, shows that surface conductivity plays as a dominant factor particularly in shaly media. In evaluating the surface conductivity, it is necessary to consider the pore geometry in that a large structure is easier to saturate rather than a small one. The high water salinity moreover can significantly reduce diffusive layer thickness and if the pore radii are very small, the diffusive layer thickness will touch each other and block an anion movement. The results further show that pore radius distribution provides more contribution to the electrical resistivity dispersion and becomes a basis to extract porosity from resistivity. The confining pressure only contributes small changes in pore geometry of media and the use of imaginary resistivity offers a better detection on it. Modified d -model and Archie's model are developed to calculate the dielectric permittivity and effective conductivity in high water salinity of saturated-rock as a function of water saturation degree.

Rock exposures around the town of Miri, Sarawak, belonging to the Miri Formation (Middle Miocene strata), represent the uplifted part of the subsurface sedimentary strata of the Miri oilfield. Data derived from outcrop studies concerning facies and sand body characteristics, and petrophysical properties are crucial for subsurface reservoir characterization and modeling of hydrocarbon reservoirs deposited in similar settings. The aim of this paper is to integrate lithofacies and petrophysical properties of Miri sandstones, in order to characterize and quantify the Miri reservoirs. The Miri Formation consists of a wide range of siliciclastic, tide-generated and storm-and wave- generated facies. Twelve lithofacies have been identified and grouped into two major facies associations: (i) the estuarine, tide-dominated, and (ii) the shoreface-offshore transition, storm-and wave-dorninated facies associations. The estuarine lithofacies are characterized by distinct and diagnostic tidal signatures; tidal dune cross-bedding with mud draped cosets and foresets including mud couplets, bidirectional (herringbone) cross-bedding, rhythmic stratifications, flaser bedding, wave bedding and lenticular bedding. Shoreface-offshore transition, storm-and-wave facies association is represented by sandstone bodies with evidences of storm and wave generated sedimentary structures; swaley cross-stratified sandstones, amalgamated hummocky cross-stratified sandstones, bioturbated sandstones and mudstone inter-bedding with parallel stratified to hummocky cross-stratified sandstone. Petrophysical properties were determined for six sandstone lithofacies: (i) Lithofacies A (multiple stacked trough cross-bedded sandstone, tidal channels and bars, estuary mouth), (ii) Lithofacies B (parallel-bedded sandstone of estuary upper flow sand flat), (iii) Lithofacies F (homogeneous coarse sandstone, outer estuarine tempestites), (iv) Lithofacies G (swaley cross­ stratified, upper-to-middle shoreface sandstone), (v) Lithofacies I (fine-grained bioturbated sandstone of the lower shoreface) and (vi) Lithofacies L (fine-grained, hummocky cross stratified sandstone, offshore transition). These lithofacies are characterized by a wide range of permeability values, which vary by several orders of magnitude (0.35 to 287 md), while porosity vary by only a few percent. Lithofacies A and F recorded the best reservoir properties; porosities are 23.3-29.7% and permeabilities are 9.64-287 md. Lithofacies G shows a wide range of porosity and permeability values that range from high to low reservoir properties; porosities are 23.5-27.5% and permeabilities are 3.4-45 md Lower shoreface and offshore transition (lithofacies I and L respectively) display the lowest reservoir properties; porosities are 13.5-24.5 % and permeabilities are 035-3.4 md In general, high reservoir quality of Miri sandstones is associated with coarser grain size, low clay contain and better sorted grains. Extensive clay drapes, bioturbation, and increasing proportion of very fine grains content result in significant decrease in permeability in both tide-generated and wave-generated lithofacies.

It has been documented that Carbonate contributes the most hydrocarbon resources worldwide. For rigorous reservoir characterization and performance prediction from seismic, the exact interpretation of geophysical response of different Carbonate pore types is crucial. Yet, the characterization of Carbonate reservoir rocks is difficult due to their complexity. Unlike clastics, diagenesis also plays a strong role in this classification. Therefore, it is difficult to establish rock physics model for Carbonate. We evaluate the possible rock physics model of twenty core plugs of a Miocene Carbonate platform in Central Luconia, Sarawak. The published laboratory data of this area were used as input to create the models. The elastic properties were analyzed to examine the validity of an existing analytical Carbonate rock physics model. We integrated the Differential Effective Medium Model and the elastic modulus which was simulated from a digital Carbonate rock image. The results matched well for the separation of Carbonate pore types and sonic velocity obtained from laboratory measurement. Thus, the results of this study show that the integration of rock digital image and theoretical rock physics have the scope to improve the elastic properties prediction and as an input for more advance Seismic Inversion of Carbonate reservoir in Sarawak.

This paper demonstrates a new alternative way in estimating seismically thin-bed (below-tuning) thickness. Initial thickness is built by bandpass filtering the amplitude display of a zero-phase seismic. The filter removes the non minimum and or non maximum and left the maximum and or the minimum of seismic amplitude. The unresolved below-tuning thickness is then corrected by zero-INTENS-difference (z-i-d) attribute. INTENS is integrated energy spectra, an attribute which can be derived from spectral analysis. z-i-d attribute is zero difference of INTENS between the seismic and its synthetic. The method generates INTENS difference profile by subtracting seismic INTENS and its synthetic INTENS iteratively. The iteration is controlled by dipole space shifting from distance to closer or vice versa. The true thickness is derived by locating z-i-d which laid in INTENS different profile. It has found that, for free noise true seismic and perfect-wavelet (a wavelet which only approximately similar with wavelet which constructing the true seismic) synthetic seismic, in INTENS different profile, the z-i-d location always corresponds to true dipole space or thickness. The method could resolve all thickness of a wedge-modeled seismic with three different dominant frequencies. When the synthetic seismic is constructed with imperfect wavelet, slightly different analysis is needed to locate z-i-d attribute and the result is not as perfect as when perfect wavelet constructing synthetic seismic. A quiet similar result is got when the method is implemented for noisy wedge-modeled seismic. Bad thickness estimation is resulted for 20% noise seismic. The method algorithm is extended for similar dipole polarity model and multilayer model to bring the method to real seismic data nearer. The extension is done by estimating thickness of every layer of a stacked-wedge-modeled seismic. The algorithm then generalized for estimating layers thickness with several thickness combinations. The method was able to delineate shallow channel of Stratton Field by providing good pseudo-acousticimpedance (pseudo AI) map.

Paleozoic sedimentary deposits are exposed in several locations on Peninsular Malaysia and may contain all the elements of a hydrocarbon system. Initial observations, mainly in the Kinta Valley, suggest the presence of source rocks, reservoirs and seals within the Paleozoic interval. The limestone hills of the Kinta Valley were the initial focus of this research project. The hills are remnants of extensive limestone beds, which are part of a very large Paleozoic carbonate complex that covered large parts of South-East Asia. The limestone beds are interbedded with sandstone, siltstone and carbonaceous shale over a thickness of up to 3000m.

A survey was carried out on a flat sandy land in the neighborhood of Gunung Datuk limestone hills complex. All 9 (NINE) boreholes drilled in this area encountered solid limestone rock at various depth ranging from 14.30 meters to 41.50 meters, indicating possible presence of karstic features. This report presents the result of 2D earth resistivity survey carried out in 2009 to provide a 3D subsurface view of the limestone head or karstic features which hopefully will help in designing the suitable foundation for any structure to be build here. Resistivity images clearly show that this area is a limestone area with karstic surface features, such as pinnacles and cavities. The depth of this zone is ranging from 8 to 35m. In some cases, some boreholes penetrated pinnacles, thus giving a false impression that the solid limestone is very shallow. In order to create a 3D subsurface view of the karstic limestone head, a total of 7 parallel lines were collected for each proposed site, and interestingly the results show, some of the proposed site were located directly above a possible collapsed cave (valley), thus special care need to be considered when designing the foundation of any structure to be build here structure.

The Miri Formation is a siliciclastic sequence consisting of a succession of coarsening upwards claysand packages where the sandstones form important oil reservoirs in the Baram Delta Province. The Middle Miocene Miri Formation, which crops out in the town of Miri in northeast Sarawak on and around the topographic feature called Canada Hill. The outcrops illustrate a complex structural geology and stratigraphy. Many authors on various aspects have studied these outcrops. However the definite stratigraphy and the structural model of the area comprising the Miri Oil Field are still questionable today.

This reference is for an abstract only. A full paper was not submitted for this conference. Abstract The risk of oil spills is high in the Straits of Melaka. Oil spills caused by collisions of ships and illegal dumping or discharge of oil in the Straits have resulted in massive environmental pollution and degradation along extensive stretches of the West Coast. To mitigate the effects of oil spills, a contingency plan based on assessment of effects of such incidents should be formulated. As a start, an investigation of the vulnerability to oil spills of the coastal environments in Perak was carried out in 2000. A preliminary classification of the vulnerability of a number of coastal facies was generated based on the Vulnerability Index of Gundlach & Hayes - which uses a scale of 1 to 10. Tidal flats and mangrove swamps were given an index of 9 to 10, as any oil spill would destroy most of the flora and fauna. Sandy beaches are placed 4 in the Index, as an oil spill would result in the oil sinking rapidly into the coarse sand. The rocky headlands, which are mostly exposed to the open seas are not vulnerable and have a scale of 1. Re-mapping of these coastal environments by remote sensing methods is currently underway. Ground-truthing is complemented by detailed assessment studies of the impact of oil spill on the sediments. Field tests are carried out on selected representative stretches of the beaches, tidal flats and mangrove swamps to characterize their physical properties and to study the infiltration rate of oil into such lithologies. The new maps generated in this study should provide the Perak State Government with the best tools to formulate an updated contingency action plan in the event of an oil spill.

The objective of this study is to model and establish a geological structure, mainly the basement rock, using potential field analysis. Two potential field methods, i.e. gravitational field and magnetic field were used in this study. The coastal margin sedimentary basin at Sungai Pahang Delta in Pekan, Pahang was chosen as the study site. This is to identify the basement rock structure due to delta development such as fault zone evolution, basement expansion and compaction. The data were interpreted both qualitatively and quantitatively. The qualitative interpretation is based on anomalies on the contour maps, and the quantitative interpretation is based on data modeling. There is good correlation between the gravitational and the magnetic field methods since the same features are found at the same locations. The result from the magnetic field method shows that the basement rock contains extended basalt intrusion. However, the gravitational data show a more localized intrusion and the presence of a metamorphism contact zone.

The Bukit Bunuh in Malaysia has recently been identified as an impact structure after the discovery of possible impact-melt-like rocks and impact breccias from this area. The impact event is believed to have occurred around 1.34-1.84 Ma. Twelve impact-related rocks from this suspected impact structure were analysed in the present study for platinum group of element (PGE) content. The sample population includes proximal impactites (two impact-melt rocks and three impact breccias) and possible impact-related rocks (four mylonites) and basement granite (three in number). The results showed no observable clear distinction between the impactites and basement granite. Compared to other asteroid impact sites in the world, the impactites and impact-related rocks in the Bukit Bunuh structure clearly contain a lower concentration of PGEs. Even though previous studies reported possible evidences of shock metamorphism in the Bukit Bunuh structure and electrical resistivity survey favoured the presence of asteroid impact structure in this area as well, the absence of a clear projectile signature in our investigation on PGE hinders further discussion on the existence and nature of the impact. We suggest that the absence of any PGE signature in the Bukit Bunuh impactites could be indicative either of (1) an achondrite projectile, or (2) an oblique impact or (3) the presence of a volatile-rich layer.

Sinkholes, cavity and fault are common phenomena in limestone area. These features can clearly be seen and avoided if they are exposed but are very difficult to be detected if it occurs below the surface. Undetected subsurface cavity and fault in a limestone quarry especially for quarries operating below a water table can create a serious problem. Water from the nearby area or river can easily penetrated via fractures into cavities system and emerges at the quarry face. This flowing water can create instability to the slope, which can lead to the collapse of the quarry’s face. Collapse of the cavity can also lead to formation of sinkhole over the surrounding area. The aim of this work is to detect the cavities and fractures system using a 2-D Resistivity Imaging Technique at an APMC cement quarry, an open cast limestone quarry in Rawang, Selangor that is about 20 km to the North of Kuala Lumpur. Results of this survey shows that various size, and shape of cavities formed along the fault system can be clearly identified. The area where surface water break through into the quarry can also be identified using this technique. In conclusion, the 2-D resistivity imaging technique was successfully being used to detect both suspected and unsuspected cavity as well as the direction of fault and fracture zone in the area.

Hydrocarbon prediction is a crucial issue in the oil and gas industry. Currently, the prediction of pore fluid and lithology are based on amplitude interpretation which has the potential to produce pitfalls in certain conditions of reservoir. Motivated by this fact, this work is directed to find out other attributes that can be used to reduce the pitfalls in the amplitude interpretation. Some seismic attributes were examined and studies showed that the attenuation attribute is a better attribute for hydrocarbon prediction. Theoretically, the attenuation mechanism of wave propagation is associated with the movement of fluid in the pore; hence the existence of hydrocarbon in the pore will be represented by attenuation attribute directly. In this paper we evaluated the feasibility of the quality factor ratio of P-wave and S-wave (Qp/Qs) as hydrocarbon indicator using well data and also we developed a new attribute based on attenuation for hydrocarbon prediction -- Normalized Energy Reduction Stack (NERS). To achieve these goals, this work was divided into 3 main parts; estimating the Qp/Qs on well log data, testing the new attribute in the synthetic data and applying the new attribute on real data in Malay Basin data. The result show that the Qp/Qs is better than Poisson's ratio and Lamda over Mu as hydrocarbon indicator. The curve, trend analysis and contrast of Qp/Qs is more powerful at distinguishing pore fluid than Poisson ratio and Lamda over Mu. The NERS attribute was successful in distinguishing the hydrocarbon from brine on synthetic data. Applying this attribute on real data on Malay basin, the NERS attribute is qualitatively conformable with the structure and location where the gas is predicted. The quantitative interpretation of this attribute for hydrocarbon prediction needs to be investigated further.

It has been recognized that carbonate reservoirs are one of the biggest sources of hydrocarbon. Clearly, the evaluation of these reservoirs is important and critical. For rigorous reservoir characterization and performance prediction from geophysical measurements, the exact interpretation of geophysical response of different carbonate pore types is crucial. Yet, the characterization of carbonate reservoir rocks is difficult due to their complex pore systems. The significant diagenesis process and complex depositional environment makes pore systems in carbonates far more complicated than in clastics. Therefore, it is difficult to establish rock physics model for carbonate rock type. In this paper, we evaluate the possible rock physics model of 20 core plugs of a Miocene carbonate platform in Central Luconia, Sarawak. The published laboratory data of this area were used as an input to create the carbonate rock physics models. The elastic properties were analyzed to examine the validity of an existing analytical carbonate rock physics model. We integrate the Xu-Payne Differential Effective Medium (DEM) Model and the elastic modulus which was simulated from a digital carbonate rock image using Finite Element Modeling. The results of this integration matched well for the separation of carbonate pore types and sonic P-wave velocity obtained from laboratory measurement. Thus, the results of this study show that the integration of rock digital image and theoretical rock physics might improve the elastic properties prediction and useful for more advance geophysical techniques (e.g. Seismic Inversion) of carbonate reservoir in Sarawak.