Rock facies prediction in non-cored wells from cored wells
AssigneeSaudi Arabian Oil Company
InventorsRoger R. Sung, Yunsheng Li, Chuanyu Stephen Sun
Life of this patent
Estimating the term…
Abstract
Facies in wells in areas of a hydrocarbon reservoir are predicted or postulated. Artificial neural networks are utilized to build a training image based on rock phases which are described and interpreted using existing data obtained from certain wells in the reservoir, and also well log characteristics of those same wells for each rock facies. Well logs from which wells where no well core data has been collected are then analyzed against the training image and the rock facies in the non-cored wells are postulated. The cost and also the possibility of damage to the wells from extraction of the core rock during drilling are avoided.
Claims30
A computer implemented method of forming with a computer system a model of rock facies of a subsurface reservoir based on well core description data about subsurface features of rock formations obtained from core samples from well bores of cored wells in the subsurface reservoir and well log data obtained from well logs from the cored wells, and on well log data from non-cored well bores from which core samples are not available, the method comprising the computer processing steps of:
- (a) forming a core description model of the rock facies adjacent the well bores of the cored wells based on the well core description data;
- (b) forming a training model of rock facies of the cored wells based on the well core description data and the well log data from the cored wells;
- (c) comparing the training model of rock facies for the cored wells with the core description model of rock facies;
- and
- (d) if the results of the step of comparing indicate a satisfactory correspondence between the training model with the core description model, forming a prediction model of rock facies for the non-cored wells in the reservoir;
- and, if not,
- (e) adjusting the training model of rock facies of the subsurface reservoir, and performing the steps of:
- (1) forming a rock facies prediction model with the adjusted training model, and
- (2) returning to the step of comparing for performing the step of comparing the rock facies prediction model so formed with the core description model of the rock facies.
A data processing system forming a model of rock facies of a subsurface reservoir based on well core description data about subsurface features of rock formations obtained from core samples from cored wells in the subsurface reservoir and well log data obtained from well logs from the cored wells, and on well log data from non-cored well bores from which core samples are not available, the data processing system comprising a processor performing the computer implemented steps of:
- (a) forming a core description model of the rock facies adjacent the well bores of the cored wells based on the well core description data;
- (b) forming a training model of rock facies of the cored wells based on the well core description data and the well log data from the cored wells;
- (c) comparing the training model of rock facies for the cored wells with the core description model of rock facies;
- and
- (d) if the results of the step of comparing indicate a satisfactory correspondence between the training model with the core description model, forming a prediction model of rock facies for the non-cored wells in the reservoir;
- and, if not,
- (e) adjusting the training model of rock facies of the subsurface reservoir, and performing the steps of:
- (1) forming a rock facies prediction model with the adjusted training model, and
- (2) returning to the step of comparing for performing the step of comparing the rock facies prediction model so formed with the core description model of the rock facies.
A data storage device having stored in a computer readable medium non-transitory computer operable instructions for causing a data processor, in forming a model of rock facies of a subsurface reservoir based on well core description data about subsurface features of rock formations obtained from core samples from cored wells in the subsurface reservoir and well log data obtained from well logs from the cored wells, and on well log data from non-cored well bores from which core samples are not available, to perform the following steps:
- (a) forming a core description model of the rock facies adjacent the well bores of the cored wells based on the well core description data;
- (b) forming a training model of rock facies of the cored wells based on the well core description data and the well log data from the cored wells;
- (c) comparing the training model of rock facies for the cored wells with the core description model of rock facies;
- and
- (d) if the results of the step of comparing indicate a satisfactory correspondence between the training model with the core description model, forming a prediction model of rock facies for the non-cored wells in the reservoir;
- and, if not,
- (e) adjusting the training model of rock facies of the subsurface reservoir, and performing the steps of:
- (1) forming a rock facies prediction model with the adjusted training model, and
- (2) returning to the step of comparing for performing the step of comparing the rock facies prediction model so formed with the core description model of the rock facies.
Dependencies are inferred from the claim text.