Evaluation of material balance methods for OGIP estimation of water-drive dry-gas reservoirs | |
| Author | Juthathat Thong-ngoen |
| Call Number | AIT Thesis no.GE-12-08 |
| Subject(s) | Gas reservoirs Material balances |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Enginee ring in Geotechnical and Earth Resources Engineering with Area of Specialization in Geosystem Exploration and Petroleum Geoengineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-12-08 |
| Abstract | Based on drive mechanism for gas reservoirs, there are two types which are volumetric depletion -drive and water-drive. Reservoir engineers commonly use the popular technique of material balance of p/Z vs. G p to estimate original gas in place (OGIP). The value of OGIP is applicable in case of volumetric depletion -drive gas reservoirs, but if the reservoirs are driven by aquifers OGIP might be overestimation . Fortunately , there are different methods of material balance to estimate OGIP in case of water -drive such as G p B g /B g -B gi vs. G p or Cole plot and G a vs . W e E/1 -E/E i . In this study, applicability of these methods was investigated to obtain a b etter OGIP estimation . ECLIPSE 100 was used to simulate to obtain OGIP for single -layered and two -layered gas reservoir production by varying aquifer size and shut -in time of both field and bottomhole pressure. The three different methods of material balan ce are also used to estimate OGIP by using the data gene rated from the simulator. Once the volumetric of OGIPs from the simulation and estimation are obtained, then they are compared to consider the error s of the estimation and to observe the effect of var ying the two parameters. The results of this study show that the error of estimation can occur from water influx and shut -in bottomhole pressure. For water influx, it can cause overestimation, negative error, and its degree is higher when the aquifer size becomes larger. For shut -in bottomhole pressure, it can cause underestimation, positive error, and its degree is higher when the shut -in bottomhole pressure is shorter in case of p/Z and Cole plot, however the degree is lower when the shut -in bottomhole pressure is shorter in case of the plot employs G a . Moreover, the error from both source s can cancel out each other, thus the total error may increase or decrease following the changes of aquifer size and length of shut -in time . In conclusion, p/Z performs well for depletion -drive to weak water -drive gas reservoir by using field pressure and shut -in bottomhole pressures, and works well for intermediate water -drive gas reservoir by using shut -in bottomhhole pressures. Cole plot performs well for depletion -drive or weak water -drive gas reservoir by using only field pressure. The plot utilizing G a performs well for weak to intermediate water -drive gas reservoir, and gives the lowest errors for strong water -drive. In case of two -layered production, p/Z performs well for depletion -drive to weak water -drive gas reservoir by using field pressure and shut -in bottomhole pressures, and works well for intermediate to strong water -drive gas reservoir by using shut -in bottomhhole pressures. Cole plot performs wel l for weak to strong water - drive gas reservoir by using only field pressure. The plot utilizing G a performs well for weak to intermediate water -drive gas reservoir by using field pressure and shut -in bottomhole pressures, and works well for strong water -drive gas reservoir by using only field pressure. |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-12-08 |
| 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;Suwat Athichanagorn; |
| Examination Committee(s) | Noppadol Phien- wej; |
| Scholarship Donor(s) | Royal Thai Government – Asian Institute of Technology Fellowship; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2013 |