Integration of SRTM and Sand Box Model for Delineation of Subsurface Structural Framework and History Match

Abdul Rauf Mirza¹, Nasir Hamim¹, Agha Hassan Akram² Muhammad Nawaz Bugti², and Ammar Ahmad²
¹Oil and Gas Development Company Limited
²Schlumberger

The Loti Field is located in the Sulaiman Fold Belt (SFB). Eighteen (18) wells in all have been drilled in the Loti Field, 12 wells are producing Gas. The primary target horizons in Loti Field are the Sui Main Limestone (SML) and Lower Ranikot (LRKT) However, the Dunghun is producing comingled with SML and Pab Sandstone produced in 1 well.

The integration of the SRTM (Shuttle Radar Thematic Mapper) data was critical during seismic interpretation for the construction of the structural framework for Loti Field, which was interpreted previously as a simple broad anticlinal structure. This was then resolved into a complex “Pop Up” structure with several en echelon faults trending in a NE – SW direction; after SRTM data was tied with seismic. This integrated structural model was also supported by a sand box model which very closely matched with complex structure revealed by SRTM data

The history match observed that the pressure drop in the field could not be explained with the assumption that the entire Gas Volume was connected.

The seismic data being scarce could not identify the compartment that would cause the expected pressure drop, hence the integration of sand box model which in the first place showed the possibility of oblique faults which could cause compartmentalization was very strongly supported by a “high intensity contouring scheme” which pinpointed the position of the oblique sealing fault required for history match. The methodology adopted here to get a better image of the subsurface by integrating SRTM and sand box models proved how critical are such data can be in absence of high resolution seismic data. The integration of the sand box model with high intensity contouring scheme exhibit how sub seismic faults which are critical for history match can be delineated realistically.

AAPG Search and Discovery Article #90160©2012 PAPG/SPE Annual Technical Conference, 3-5 December 2012, Islamabad, Pakistan.