Dear Oil and Gas professionals, Regarding to Hidden Productive Plays from High Water Saturation zone, I'd like to share my experience to identify such zones. We drilled a development well penetrated several reservoirs having medium resistivity (9-11 ohm.m) and low contrast (but high gas reading during drilling). As usual, we run conventional log analysis to identify zones of interest, the results indicated that those zones are not identified as hydrocarbon bearings (high Sw). We then leaved these zones as water bearings.
The increase of oil price triggred us to re-evaluate all the wells that might have potential hidden oil reservoirs. After we run a thorough evaluation, we back to this well and run production test on the suspected zone. The results indicated that this zone produced oil at initial rate 500 BOPD. To confirm the presence of oil in the other reservoirs having similar resistivities (low/medium res, low contrast), we then run advance log analysis to identify hidden reservoir provided by one of the service companies. The lesson learn from this case, probably, you still have potential hydrocarbon reserves hidden in your reservoirs (penetrated by your old wells). Rergards Yodi G. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Thursday, May 13, 2004 9:23 PM To: [EMAIL PROTECTED] Subject: [oilgasprof] Hidden Productive Plays from High Water Saturation Zones Dear Oil and Gas professionals Hidden Productive Plays from High Water Saturation Zones. Conventionally, high water saturation (Sw) formation is considered as water zone. Infact, the nature has proven that some of the formations with high Sw are able to produce dry oil or gas. The additional reserves of about 30% from the existing reserves could be booked if the hidden reservoirs from high Sw zones are able to be identified. The high Sw value is normally generated by low resistivity, Rt. Based on the Archi's equation, Sw is inversely related with Rt, the lower the Rt the higher Sw. The Archi's equation assumes that the fluids in the formation are mixed electrically with no short circuit condition. In the case of short circuit the Rt drops very low causing high Sw values and fail to reflect the real water saturation. One example of the low resistivity phenomenon due to the short circuit condition is the conductive effect of formation grains. The conductive grains containing oil in a reservoir system provides very low resistivity. The electrical current flowing into the reservoir system is short circuited by the conductive grains giving very low Rt reading. If this Rt reading is applied into the Archi's equation, the calculated Sw will be very high and conventionally this zone is considered water. The other example of the low resistivity reading is the micro electrical channeling. The micro electrical channeling is built by irreducible water surrounding small grains in the reservoir. As the irreducible water is normally conductive, the electrical current flowing into the reservoir during the resistivity logging will be short circuited by the irreducible water causing low resistivity reading. This low ressitivity zones will produce high Sw and again the formations are considered as water zones. The existence of oil in the reservoir pores among the irreducible water can not therefore be identified. Those two phenomena create hidden billion dollars plays in the current reservoirs. An advanced petrophysical evaluation method has therefore to be created to identify them. One of the successful and economic method is using Nutech proprietary Cross Plots and algorithm. The output will provide the water composition between moveable and non moveable. High Sw formations with 100% non moveable water will produce dry oil with zero water cut. I would be highly appreciated if you could share your experience in the advance petrophysical evaluation. Warmest Regards Hasan Hambali Cell Phone : +62 812 995 1902 * If you have any problems posting your messages, just send the info to [EMAIL PROTECTED] * Hotel for Meeting or Gathering? Hotel Salak The Heritage in Bogor, your recommended hotel, 45' from JKT and free from disturbing routine activities (more focus). Where historical values and modern technology meet. http://www.hotelsalak.co.id, Email:[EMAIL PROTECTED] * Oil and Gas IT works, Bee Software and IT Company is your solution to optimize your operations. Call or send sms to Nila +62 812 836 5735 * If you feel disturbed with this email just send a blank email to [EMAIL PROTECTED] and follow further instructions from the Yahoo. Yahoo! Groups Links ------------------------ Yahoo! Groups Sponsor ---------------------~--> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar. Now with Pop-Up Blocker. Get it for free! http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/9rHolB/TM ---------------------------------------------------------------------~-> * If you have any problems posting your messages, just send the info to [EMAIL PROTECTED] * Hotel for Meeting or Gathering? Hotel Salak The Heritage in Bogor, your recommended hotel, 45' from JKT and free from disturbing routine activities (more focus). Where historical values and modern technology meet. http://www.hotelsalak.co.id, Email:[EMAIL PROTECTED] * Oil and Gas IT works, Bee Software and IT Company is your solution to optimize your operations. Call or send sms to Nila +62 812 836 5735 * If you feel disturbed with this email just send a blank email to [EMAIL PROTECTED] and follow further instructions from the Yahoo. Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/oilgasprof/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ _______________________________________________ Pb mailing list [EMAIL PROTECTED] http://dml.or.id/mailman/listinfo/pb_dml.or.id
