Publications

The 5X well was reached final depth at 11,012 ftMD and encountered ~300 ft net sand of Eocene Lama Fm. Most of the sands are considered poor quality/tight, but highly fractured, which can be confirmed by the image logs. The drilling of 5X well encountered several losses, which indicate the presence of secondary porosity. Maximum total gas reading of ~87 units, with background gas of 5-10 units, was recorded at 12 ppg mud weight. LWD run were GR-Res-Den-Neutron, with dipole sonic, image log, RDT, side wall core and VSP (wireline) were also acquired. Pressure gradient could not be established and no success in fluid sampling. Despite of poor quality reservoir look (on most of the conventional well data), the DSI-derived Stoneley permeability suggested that the targeted Lama sands could have decent permeability. This is consistent with the image logs data and drilling losses history. Fluid replacement modeling (FRM) was performed to model various responses of elastic properties, such as Vp/Vs ratio, to predict the fluid type. Several FRM cases were run, (1) Insitu - actual log response, (2) Insitu Parameters with Gas Saturation, (3) Brine, (4) Insitu with Porosity ~15%, and (5) Wet Case with 15% Porosity. The modeling suggests: P-impedance of Insitu Case is higher when it is replaced by water, but increasing the porosity up to 15% will lower down the impedance. The 100% Gas Replacement Case gives quite similar response to Insitu Case. The Insitu response is identical with gas filled sand response. There are no significant changes/drops in Poisson’s Ratio (PR) from all the Wet Cases (similar with the background shales). However, the Gas and Insitu Cases show drops in PR response, suggesting the Insitu Case has similar PR values as the Gas Cases. The geophysical modeling is one of the useful tools which can be implemented to help the observation, interpretation or even to support an exploration decision, especially when the other data are inconclusive. In the case of 5X, the above mentioned methodology was used and implemented to support the collective decision to test the ‘poor’ Lama D sand. The sand successfully flowed ~17 MMSCFD at 48/64” choke size. Currently, two appraisal wells are planned to be drilled as a result of 5X well discovery.