Basin modelling : how well have we done ?

Model developers have been highly successful in building usable, useful, and reliable one-dimensional models, and in convincing explorationists to use them. Development of convenient, universal software played an instrumental role in the acceptance of 1-D modelling. The remaining weaknesses in technology and training, while serious, can be resolved through a few years of intensive work in certain specific areas. 2-D and 3-D fluid-flow modelling, in contrast, finds itself today largely in the position occupied by 1-D modelling more than a decade ago. The concept of fluid-flow modelling has not yet been adequately sold to explorationists, mainly because existing software is often inadequate to meet the real needs of exploration personnel. Development of appropriate software will probably have to precede widespread popularization of fluid-flow modelling. To improve existing software, two major areas must be addressed: (1) making models more comprehensive by including all relevant geologic phenomena, and (2) making software easier to use. The general topic of basin modelling includes both 1-D modelling (often called maturity modelling) and 2-D and 3-D fluid-flow modelling (sometimes itself called basin modelling). Both types of modelling are in some senses like the mythical monster Hydra, in which dangerous new heads grow as fast as old ones can be cut off. Over the past decade but principally during the past five years we have solved some important problems in maturity and fluid-flow modelling. However, the solutions to old problems have often uncovered additional hitherto-unrecognized issues, often of equal importance. This paper will discuss both those heads that we have succeeded in lopping off, and the new ones growing from the old roots. The discussion is divided into four parts. The first two discuss the successes and the remaining problems in 1-D (maturity) modelling. The remaining two parts discuss 2-D or 3-D modelling carried out for the additional purpose of studying pressure and fluid flow (particularly hydrocarbon