Quantitative Model for Basin Analysis and Its Application to Northern North Sea Basin

Song Cao, Ian Lerche, Christopher G. St. C. Kendall

A new deterministic computer model, which handles one-dimensional compaction, fracturing, overpressuring, cementation, dissolution, and fluid flow, has been developed for petroleum explorationists to make quantitative studies of sedimentary basins. The outputs of this model include burial history, thermal history, hydrocarbon generation, and migration history. The model uses Darcy's Law to handle fluid flow and its relationship to compaction, as well as the 1985 inverse model of Lerche et al for thermal indicators, and a modification of Tissot's hydrocarbon generation model. The following results can be obtained from the model: (1) amount of basin subsidence (sediment load and tectonic effect); (2) determination of erosion thickness of an unconformity; (3) changes of poro ity, permeability, fluid flow rate, and pore pressure with time and depth; (4) heat flow history; (5) temperature change with time and depth; (6) fracture timing in relation to hydrocarbon generation timing; (7) value of thermal maturity indicators (such as vitrinite reflectance) that change with time and depth; (8) hydrocarbon generation history, including time and depth of peak hydrocarbon generation; and (9) prediction of possible direction of hydrocarbon migration and accumulation.

The model can be applied to frontier basins, where only a few wells have been drilled, and well-developed basins. The input data for the model can be based mainly on commonly used geological and geochemical data from one well from a frontier basin or on similar data from many wells in a well-developed basin.

The results for the northern North Sea basin are based on data from more than 100 wells. We believe the results are helpful (1) for increasing our understanding of the integrated evolutionary picture of the northern North Sea basin, and (2) for providing a more reasoned exploration strategy in undeveloped and underdeveloped areas of the basin.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.