Building Porosity Model of Coalbed Using Collocated Cokriging

A porosity model needs to be built in Zaoyuan well pattern of Qinshui basin. There are 14 development wells in Zaoyuan well pattern, but only two wells have the data about porosity of coalbed. The analysis of 17 samples revealed that there existed a good negative linear relation between ash content and porosity, and there are analysis data about ash content for all 14 development wells. So, the porosity distribution can be predicted by use of information provided by ash content. The collocated cokriging method is used to simulate porosity distribution. The model of coal ash content was built firstly, then adopting the coal ash content as second variable, the porosity model was built. The result shows that the porosity model built by integrating ash content data can characterize the distribution and heterogeneity of porosity more subtle and reliable. It can take the advantage of that ash content data can be gotten easy.