Quantitative Interpretation of Seismic Facies - A case study, Oriente Basin Ecuador
Summary Interpretation of several 3D volumes from the Oriente basin suggests that faults define the extent of a given field. Additionally, the subtle stratigraphic boundaries characterised by the clay-filled zones of low porosity compartmentalise oil pools within a field. Identification of these zones is critical. In our experience, neural network based waveform classification has proven to be a successful tool to identify these zones. Qualitative analysis of seismic facies derived from the classification is a common practice. However, we demonstrate in this paper that the quantitative interpretation of seismic facies is possible provided a geological understanding of the seismic signatures is achieved. This paper discusses the extensive 1D-modeling carried out to comprehend the trace shape variations due to changing isopach of the sand/shale sequences, which was fundamental in assigning a realistic geological model to each facies. Also described in the paper is the workflow and a key methodology developed to derive “Net thickness” of reservoir sands from the seismic facies. Rigorous study of this technique on several 3D data sets from Ecuador’s Oriente Basin has produced results, which have established the foundation for understanding the depositional environments and the reservoir models, validated by subsequent drilling.
Deep Plugging Experiments Study in High Temperature and Salinity Heterogeneous Clastic Reservoir
According to the exploration and field test results, the reservoir presents high temperature (96°C) and high salinity (77954.03 mg/L) features; therefore, it is necessary to find proper plugging agent that can be used in these reservoirs to enhance oil recovery. In this paper, three kinds of polymers are studied and high temperature resistance as well as relative parameters are tested. According to the testing results, we make a preliminary determination that concentration of polymer solution is 2500-3500mg/L. However, due to the high reservoir temperature, APP5 polymer degrades severely. In view of the polymer degradation problem in high temperature, 2.7% chromium acetate is added into the APP5 solution (Cr/APP5=1/60), and the retarder is added at the same time. The stability of this new plugging agent is then tested. The results show that, when the shearing time reaches 60s, plugging agent remains at a high level of 24600mPa•s, and the static adsorption of APP5 remains at a low level of 0.36-0.38mg/g. As a consequence, the Cr/APP5 plugging agent can meet the production requirements in reservoirs. Based on results of laboratory physical simulation experiment, plugging efficiency of this plugging agent is higher than 75%, and injected slug size of Cr/APP5 plugging agent is 0.3PV.
Coup d'oeil sur les provinces géantes d'hydrocarbures
Vingt provinces geantes de plus d'un milliard de tonnes de petrole ou d'equivalent gaz, se repartissant assez bien suivant une loi log-normale, concentrent aujourd'hui 90 % des decouvertes cumulees d'huile et pres de 80 % des reserves de gaz. Ces provinces, situees plus particulierement dans l'hemisphere Nord, occupent des positions remarquables dans un cadre geotectonique d'ensemble. L'analyse de leurs caracteristiques geologiques et petrolieres fait apparaitre notamment la predominance de pieges structuraux, de discordances regionales et d'un habitat de type concentre. L'histoire de leur decouverte et de leur exploration montre une certaine acceleration qui semble culminer au cours des annees 1950-1960. Le rendement de l'exploration de ces provinces est generalement eleve, a l'exception des provinces nord-americaines, theâtre d'une prospection intensive des avant la Deuxieme Guerre mondiale. Ces rendements eleves paraissent en etroite relation avec leur richesse, l'habitat concentre et le niveau des techniques.