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.
Classification of Seismic Windows Using Artificial Neural Networks
We examine the plausibility of using an Artificial Neural Network (ANN) and an Importance-Aided Neural Network (IANN) for the refinement of the structural model used to create full-wave tomography images. Specifically, we apply the machine learning techniques to classifying segments of observed data wave seismograms and synthetic data wave seismograms as either usable for iteratively refining the structural model or not usable for refinement. Segments of observed and synthetic seismograms are considered usable if they are not too di erent, a heuristic observation made by a human expert, which is considered a match. The use of the ANN and the IANN for classification of the data wave segments removes the human computational cost of the classification process and removes the need for an expert to oversee all such classifications. Our experiments on the seismic data for Southern California have shown this technique to be promising for both classification accuracy and the reduction of the time required to compute the classification of observed data wave segment and synthetic data wave segment matches.
STUDIES ON TERRESTRIAL CONTAMINANTS OF METEORITES
During t h e l a s t ha l f d e c a d e a n unpara l le led upsu rge h a s t aken p l ace in t h e s tudy of meteor i tes , e s p e c i a l l y t h e ca rbonaceous chondr i tes . S c i e n t i s t s from all ove r t h e world, employing t h e newes t a n d most s e n s i t i v e an a1 y t i c a l t ec hni q u e s , i n v e s t i g a t e t h e ch e m i c a l composition of t h e o rgan ic mate t ia l found in t h e s e meteor i tes . In t h i s way they a r e trying to de te rmine t h e phys ica l c o n s t a n t s of t h e meteor i tes and e s t a b l i s h , on t h e b a s i s of minera logica l and petrolog ica l s t u d i e s , t h e cha rac t e r i s t i c s of t h e environmental condi t ions f r o m which t h e s e s t o n e s or ig ina ted and to desc r ibe and ident i fy cer ta in mic ros t ruc tu res which abound in s o m e of t h e s e ca rbonaceous chondr i tes . A l l of t h e s e research i n t e r e s t s a r e d i rec ted towards o n e pa r t i cu la r problem, t h e def in i te so lu t ion of which may indeed have revolutionary e f f e c t s o n ou r c o n c e p t s of t he universe. T h e ques t ion is whether or not t h e s e meteor i tes conta in t r a c e s of ex t ra t e r r e s t r i a l l i fe , t hus proving tha t some kind of biota eve r e x i s t e d o ther t han on t h e ear th , o r if a l l of t h o s e f ea tu res tha t t end to subs t a n t i a t e t h e prev ious ly mentioned h y p o t h e s i s a r e only t h e r e s u l t of contaminat ion by te r res t r ia l matter. T h e impor tance of t h i s problem w a s emphas ized by Berna l (1961: 130) in t h e following way: “ T h e v i t a l ques t ion cou ld be s e t t l e d o n c e and for a l l if s p e c i f i c molecu le s s u c h a s porphyrins o r nuc leo t ides were found. A counter ind ica t ion a t t he moment is t h e extremely low phosphorous conten t of t h e meteorite.” S ince tha t s t a t emen t w a s made, porphyrins (Hodgson & Baker, 1964) a n d poss i b l y nuc leo t ides (Nagy et al., 1963a) have been ident i f ied f r o m t h e Orgueil meteor i te , but s t i l l t he q u e s t i o n of t h e e x i s t e n c e of extrat e r r e s t r i a l life is far from be ing proven. I t is clear from the a b o v e tha t o n e of t h e b a s i c problems tha t o n e faces in t h e s tudy of meteor i tes is tha t of contamination. In order t o e s t a b l i s h unques t ionably t h e e x i s t e n c e o r p a s t e x i s t e n c e of ex t ra te r res t r ia l l i f e through t h e s t u d i e s of meteor i tes , two primary q u e s t i o n s h a v e to b e dea l t with s imul taneous ly . O n e h a s to d e c i d e