| Author | Wickrama, Madappuli Arachchige Don Maheshwari Gangawo |
| Call Number | AIT Thesis no.GE-14-16 |
| Subject(s) | Oil wells--Testing
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Geotechnical an d Earth Resources Engineering with a rea of Specialization in Geo - exploration and Petroleum Geoengineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-14-16 |
| Abstract | The dynamic behaviour of a petroleum reservoir is primarily controlled by the properties of the reservoir and fluid. With the well testing data one can determine the hydraulic properties of the r eservoir. The main objective of this study is to find out a relationship between formation damage zone and skin of an oil well. A method was developed to help a better understanding of time dependent pressure drop and skin of the radial flow to the well. Well flowing pressure for several reservoir models, constructed by varying the permeability and the radius of the damage zone, were calculated using the proposed analytical solution for radial fluid flow towards the well.. Then the calculated well flowing pressure curves were back - analysed by semi - log analysis to determine permeability and the skin factor. Then the variation of the skin with the ratio between radius of the formation damage zone and the radius of well bore (r s /r w ), for different ratios betwe en permeability of the damage zone and permeability of the virgin zone (k s / k) was investigated. Permeability values calculated from semi - log straight line analysis are similar to the input reservoir permeability. A plot was constructed to present the va riation of the skin factor with the ratio of r s /r w for various k s /k ratios for clastic reservoirs. The calculated skin factors are within normal range of the skin value. It was found that for the negative range of the skin factor ,” - 2” was the maximum valu e could reach for the range selected for r s /r w (from 1.3 to 66.7) . Higher magnitude in negative skin recorded in the industry may be a result of increase of the effective well bore radius.Well testing data from a fractured granite basement reservoir stud ied by Minh (2005) and Khupviwat (2014) were re - analyzed in this research. Fractured granite basement reservoir was considered as a 3D fracture system, which at some extent would behave as clastic reservoir and, therefore one can make use of the graph deve loped in this study to determine the permeability or the radius of the damage zone. Skin value calculated is ( - 3.57), which is beyond the range of the graph developed in the study. Minus ( - ) sign of the skin indicate the higher fracture density in the dama ge zone. High numerical value might be due to the increase of effective well bore radius. For a damage zone having permeability 100 times greater than that of virgin zone, effective radius would be around 14ft for the well testing data studied. |
| Year | 2015 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-14-16 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Pham Huy Giao; |
| Examination Committee(s) | Noppadol Phien - wej;Tian Ho Seah; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2014 |