Muhammed Y Jallow

Reservoir Characterization involves a holistic approach of describing a reservoir by integrating geologic, geophysical, petrophysical and reservoir engineering using all available data for the characterization of the reservoir’s geometric features (including structural and stratigraphic controls) and Petrophysical properties (including porosity, permeability and fluid saturation). The focus is to understand and identify the flow units of the reservoir and predict the inter-well distributions of relevant reservoir properties. JAY field was characterized via Petrophysical analysis, seismic interpretation and modelling, and rock physics analysis. Porosity and permeability models were generated and combined with petrophysical analysis in characterizing the delineated reservoirs. The rock physics cross-plots were used to quality check the results from the seismic and Petrophysical analysis. The structural interpretation of the 3D seismic data of the field revealed anticlinal structures (four-way closure) which is fault assisted and can thus allow hydrocarbon accumulation. Four of the faults are major listric faults that trend in the Northeast Southwest direction. Amongst the remaining fourteen minor faults, five of them are synthetic faults whose sense of displacement is similar to its associated major faults while others are Antithetic faults. Four horizons were established which indicated the top and base of the two reservoirs. The Petrophysical analysis indicated that the reservoirs have good pore interconnectivity (Average ∅𝑒𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒= 24% & 21% and Average 𝐾𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = 9701md & 7737md for Sand A and B respectively.) The rock physics analysis confirmed the result obtained from the Petrophysical analysis and furthermore, it showed that the lithologies within the lower portion of the reservoir were partially cemented. Also, the reservoir is found to be predominated by water followed by gas by both rock physics and petrophysical analysis.

The Industrial Training has helped exposed and prepare me for industry, during my internship program at Petrodata Management Services Limited, I worked on the transcription and seismic Navigation merge of the 3D data of OML118 (Bonga field) in Niger Delta, using seismic and  Navigation data. The aim of carrying out this project is to move the seismic data from a lower media (IBM3590) to a higher media (IBM3592) seismic tape cartridges and as well as assigning coordinates to the SEGD data using the positional data. There was a need to carry out the project because of the lower media seismic tape drives and tapes are becoming obsolete and hence, support from IBM its producers has been stopped. The DPTS software was used in carrying out both the transcription and navigation merge. The field data was reformatted to the internal format of P.M.S.L. The MTC4 module was used for the transcription of the data and also the removal of the encapsulation (file extractions) in order to obtain the BIN file. The UKLIST module was used to extract the seismic lines and shot point number which was matched with the navigation datasets to obtain the shot information. And the merge was carried out using the DEMUX module of the DPTS software and all shot information from the navigation data was written to the SEGY trace header output. The result obtained from the transcription was six IBM3592 outputs which accommodated the entire data copied from the IBM3590 seismic tape cartridges. Navmerged data in SEGY format with shot information including items such as the Vessel id, source id, and shot time. Two times from the seismic were also inserted. Thus the SEGY provides an audit trail of how the merge was carried out. The transcription of the data reduced the number of seismic cartridges which in turn reduced cost of storage and transportation. Also reduced the risk of losing the data because the seismic drives that could read them are becoming obsolete.

The geophysical assessment of groundwater in Igarra, Edo state, south western Nigeria which lies between latitude 7015IN to 7020IN and longitude 604IE to 608IE was carried out with the aim of delineating probable areas of high groundwater potential. The area falls within the Crystalline Basement Complex of southwestern Nigeria. The geophysical investigation involves the very low frequency electromagnetic (VLF-EM) and Vertical Electrical Sounding (VES) methods. The VLF EM survey was at 5m interval along five traverses ranging from 100South to 100North (i.e. 200m in length) using ABEM WADI VLF-EM unit. The VLF-EM survey was used to delineate areas with conductive/fractured zones by plotting both the raw real and filtered real against the distance and using the Karous-Hjelt to determine the depths. Thirteen (13) vertical electrical soundings were acquired along three (3) traverses using the Schlumberger array which were carried out with the use of Ohmega resistivity meter. The groundwater potential of the area has been based on aquifer geoelectric parameters obtained from VES interpretation results, isopach and isoresistivity map. The result of VLF-EM survey along its traverse was used in delineating high conductive or fractured zones. The VLF profiles showed maximum peak at both the positive and negative region. Prominent positive filtered real peak usually signifies fractures, contact zones or presence of clayey materials (F1, F2, F3a, F3b and F5). Areas where both the raw real and filtered real positive peak coincides signifies a thick overburden (T1, T2a, T2b and T4) while were both negative peaks coincides signifies a shallow overburden (S2 and S5). The VES results showed three (3) to four (4) geoelectric layers inferred as topsoil, saturated layer (clayey), weathered layer and fractured/fresh basement. The combination of these two methods, therefore, helped in resolving the prospecting location for the groundwater yield in the study area. The thickness of the top soil ranged from 0.1 to 1.3m while the resistivity values varied from 51 to 47 Ωm. the saturated layer thickness varied between 0.1 and 1.3m while its resistivity ranged between 9.8 to 52 Ωm. The weathered and fractured aquifers constituted the main aquifer units having thickness of 0.5 to 87.3m. The fractured/fresh basement resistivity ranged between 8825.8 Ωm to infinity. The overburden thickness ranged between 3.5 to 91.9m. The combination of electromagnetic profiling and vertical electrical resistivity surveys in the study area has contributed to a better understanding of the groundwater occurrence in this part of basement complex of Igarra, Edo state. Integration of VLF-EM and electrical resistivity sounding results enabled identification of good site for productive borehole and groundwater in a typical crystalline terrain as the studied area.