Application of the Natural Gamma Ray Spectrometry and XRD Diffractometer in the High Resolution Stratigraphy Genetic Parasequences in the Hassi Messaoud Field. Case Study: The Cambrian Reservoir

Kerdjidj Mohamed-Kamel, Sonatrach Exploration, Boumerdes, 35000, Algeria, phone: 213 71 66 05 67, fax: 024 81 90 78, mkkerdjidj@yahoo.fr, Madani Messaoud, Sonatrach Production; geology department, SONATRACH DP BOITE POSTALE 50 IRARA HASSI MESSOUD, Hassi Messaoud, 30500, Algeria, and Sahli Mohamed, Halliburton/ENSP, Hassi Messaoud.

The Hassi messaoud field is very thick sandstone reservoir covering an area of 2000 quare km. The producing layer, wich occurs at an average depth of 3400m, is caracterized by very variable petrophysical properties. This properties impacting on productivity remain unpredictable despite the knowledge accumulated from 1000 wells continously cored the past 40 years. The Cambrian series is subdivided in the four following terms in ascending order R3,R2,Ra and Ri.The clay fraction is composed by interstratified illite, kaolinite and illite. The distribution of illite is discontinuous with weak diffractive intensity, but associated with kaolinite. There are two classes of kaolinite crystallization, weak and strong crystallization.. Generally, good kaolinite crystallization is found in the bottom of the hydraulic layer opposed to the top, which could have been periodically inundated with ground water as a result of seasonal piezometric fluctuations. The curves for thorium and uranium tend to track one another and are lower where kaolinite is poorly crystallized and strong where kaolinite is well crystallized. This degree of crystallization could be a good parameter to subdivide the hydrocarbon reservoir with increased resolution.

Petroleum Geology, Exploration Successes and Future Potential in Algeria
AAPG & AAPG European Region Energy Conference and Exhibition (November 18-21, 2007) Technical Program