8122019 ALAGO Petrologia Primer Panel FINAL 2

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The Basque-Cantabrian Basin has been consi-

dered one of the most interesting areas for

hydrocarbon exploration in Spain The basin ischaracterized by numerous outcrops of tar

sands related to fractures and Triassic salt dia-

pirs In the western part of the basin are located

the sole onshore oil 1047297eld in Spain

OPTICAL and CATHODOLUMINISCENCE MICROSCOPY (OM amp CL)

OUTCROPS

ATAURILOZA MAESTU

ATAURI

MAESTU

LOZA

LOZAA) OM photomicrograph of a sublitharenite showing bladed calcite cement (CC) and oil (O) 1047297lling the re-

maining pore space

B) CL pair of A showing the typical orange luminescence colour of bioclasts and dull luminescence ofbladed calcite cement

C) OM photomicrograph of a sublitharenite showing micritic matrix embedded in oil (O) Note the corro-ded calcite cement overgrowth (CC) around the crinoid fragment (CR) (ie the oil emplacement ispre-dated by the calcite overgrowth)

D) CL pair of C showing dull luminescence of calcite cement and orange luminescence colour of the cri-noid fragment

MAESTU

E) OM photomicrograph of a grainstone showing calcite overgrowths over forams post-dated by oil em-placement

F) CL pair of E showing homogeneous brown luminescence of both bioclasts and calcite cementsG) OM photomicrograph of a dolomitized grainstone showing corroded and fractured dolomite crystals

post-dated by oil emplacementH) CL pair of G showing homogeneous red-to-brown luminescence colour of both dolomite crystals and

clasts Calcite cement crystals show zoned bright orange luminescence colour

ATAURII) OM photomicrograph of a grainstoneshowing a fracture zone partially cemented by calcite cement

Residual porosity is in1047297lled by oilJ) CL pair of I showing homogeneous red-to-brown luminescence colourK) OM photomicrograph of a grainstone showing two generations of calcite cement 1047297lling intergranular

porosity The oil emplacement occurred between both cement generations

L) CL pair of K showing homogeneous red-to-brown luminescence colour

The Upper Campanian - Maastrichtian sediments constitute an exhumed reservoir The later is formed by fossiliferous limestones locally dolomitized and

calcareous sandstones Hydrocarbons (asphalts) appear in inter and intragranular fracture and vacuolar porosities Asphalt exudes and 1047298ow during summer

time when temperatures are relatively high

A Permanyer (1) R Mar1047297l (2) J Estupintildean (2) P Mariacuten (1) JD Martiacuten-Martiacuten (1)

ORGANIC AND INORGANIC CHARACTERISTICS OF EXHUMED RESERVOIRS

UPPER CRETACEOUS NORTH SPAIN (1)

(1)Universitat de Barcelona (albertpermanyerubedu) (2)Universidad Complutense de Madrid (mar1047297lgeoucmes)

O = oil CR = crinoids F= forams CO = corals CC = calcite cement Q = quartz D = dolomite

O

O

O

CR

CO

A B

C D

250 μm50 m 250 μm50 m

250 μm50 m250 μm50 m

O

O

O

O

O

O

DD

CC

CRCR

F

F

F

F

E F

G H

250 μm50 m 250 μm50 m

250 μm50 m250 μm50 m

O

O

O CC

F

I J

K L

250 μm50 m 250 μm50 m

850 μm50 m 850 μm50 m

NSantander

Gernica

San Sebastiaacuten

Vitoria

Dominio

Peri-Asturiano Arco Vasco

Cubeta Alavesa

Golfo de Vizcaya

Pamplona

Estella

20km

Upper Cretaceous

Lower Cretaceous

Jurassic

Triassic (Keuper)

Paleozoic

Paleogene

Neogene

Cinco Villas

Macizo

Asturiano

Alduides

Bilbao

Ayolueng o

oil field

Duero Basin Ebro Basin

Spain

Cantabrian Sea

BASQUE - CANTABRIAN BASIN

discordance

fault

mecanicalcontact

thrust

reverse fault

normalfault

diapir

anticline

syncline

Locality Outcrop

Keuper

Muschelkalk

Buntsandstein

Jurassic

Lower Cretaceous

U p p e r

C r e t a c e o u s

Santonian - Cenomanian

Maastrichtian -Campanian

Eocene -Paleocene

Pliocene -Oligocene

Quaternary

T e r c i a r y

Atauri

Maestu

25km 2 ordm 4 5 1 0 5

42ordm35043

Pentildeacerrada Loza

Oquina

Urarte

Santa Cruzde Campezo

MAESTU ATAURI

LOZA

normalcontact

T r i a s s i c

UNIVERSIDAD

COMPLUTENSE

MADRID