Modelling of bulk modulus from sand [API <75]-shale [API >75] lithology for XA field in the Niger Delta Basin

Abstract

Modelling of bulk modulus from sand-shale lithology has been researched. This is to come up with a model than relates the bulk modulus with the Lame’s first parameter. Data adequate for this finding were obtained from three Niger Delta oil wells A, B and C. Microsoft Excel was used for all stages of analysis. The result indicates the average values of Poisson’s ratio and Vp/Vs ratio as 0.5 and 1.637 respectively for all wells. Other results include the depth range of about 5300ft to 6600ft; shear modulus varies from 4.05 x 109 to 11 x 109N/m2; the range of result of young modulus varies from 1.21 x 1010 to 3.18 x 1010N/m2; Lame’s first parameter range from 2.75 x 109 to 7.20 x 109N/m2; bulk modulus values are within 1.08 x 1010 to 2.84 x 1010N/m2; the elastic parameters with peak values are noted at the depth of 6200ft for well A. For well B, the results indicate the depth of investigation as 8300ft to 10000ft; shear modulus varies from 5.76 x 109 to 10.00 x 109N/m2; the range of young modulus varies from 1.73 x 1010 to 3.04 x 1010N/m2; Lame’s first parameter range from 3.90 x 109 to 6.87 x 109N/m2; bulk modulus values are 1.54 x 1010 to 2.71 x 1010N/m2; the elastic parameters with maximum values are recorded at the depth of about 9900ft. For well C, the depth ranges from 5200ft to 8200ft; shear modulus varies from 7.84 x 109 to 1.35 x 1013 N/m2; the range of result of young modulus varies from 2.35 x 1010 to 4.04 x 1013N/m2; Lame’s first parameter range from 5.32 x 109 to 9.14 x 1012N/m2; bulk modulus values are within 1.05 x 1010 to 1.81 x 1013N/m2; the elastic parameters with peak values are noted at the depth of 8200ft. The relationship between bulk modulus and Lame’s first parameter obtained is K = 3.9455λ or (K = 4λ). Lame’s first parameter analysis could permit a better resolution of potential hydrocarbon zones; therefore, in a linear relationship with bulk modulus of about 1.0 correlation coefficient would yield a model which is adequate for mapping of hydrocarbon accumulation.