... principles are increasingly being extended to a wider range of drilling, workover and completion operations. The same reservoirs that show positive economics results from the use of UBD technology are also good candidates for other live well operations. In fact, the investment in UBD operations and resulting...

.... By 1996 offshore coiled tubing UBD projects were under trial with success - offshore Denmark by Maersk and by NAM onshore in the Netherlands. Other smaller projects were executed by Pentex Oil and Candecca Resources onshore UK. A four well UBD programme was executed by WAPET in Australia using...

... society of petroleum engineers reservoir characterization lateral contribution workover application reservoir mmscfd productivity ubctd rate gain Introduction In the Underbalanced Drilling (UBD) process, the wellbore pressure in the open hole section is kept below the reservoir pressure...

...)-Introduction to UBD, UBD techniques, benefits of UBD equipment, selecting an appropriate candidate, and UBD well engineering Advanced drilling technologies – casing drilling, HPHT, managed pressure drilling, dual gradient drilling, special well control issues Non-conventional drilling methods...

.... There is no wall cake and no over pressure to push the pipe against the wall of the wellbore. Of course It does not mean that no stuck pipe occurs when drilling underbalanced. PR-66 well was drilled UB in its workover program. Stuck pipe happened in this operation whereas it was one of the UBD wells of Parsi...

... Drilled underbalanced horizontal oil producer lateral; 1,102, 1,443 and 1,725 ft long, in the targeted zones of the Arab D reservoir for wells UBD Oil-1, UBD Oil-2 and UBD Oil-3 respectively. Improved rate of penetration (ROP) while drilling: Total on bottom hours drilled for UBD Oil-1, UBD...

... the chance of mud invasion into reservoir, the reservoir rock is in as natural condition as possible. One amazing thing that has been seen is that up until now conventionally drilled Nimr wells would almost never free flow to surface even under workover conditions. With UBD, most of the wells will free...

... for Model Parameters Abstract During under-balanced drilling (UBD) of a horizontal well, down-hole pressure and temperature, as well as surface rate and pressure data are acquired. Theoretically, estimation of reservoir permeability profile can be achieved by quantitative analysis of these data...

... Successful application of UBD requires a detailed understanding of the potential benefits as well as limitations. Drilling activities in old fields have a paramount importance, either in trying to maintain the production level, or in reaching untapped hydrocarbon pools. Workover activity is also generally...

...Multiphase Flow Modeling A commercially available UBD hydraulics modeling program was used to perform multiphase modeling on the generic well. The preliminary modeling showed that underbalanced conditions with no flow were not a problem using 2 in. OD CT and diesel as the drilling fluid...

...Abstract Abstract Due to possibility of sub hydrostatic pore pressure, a nitrified water system was selected in a 2 well underbalanced drilling (UBD) campaign in West Malaysia for reservoir characterization and productivity. The first well was drilled with nitrified seawater in the first UBD...

... the mechanisms of productivity improvement from UBD must be performed. A single-well model can be built that simulates the UBD process and the OBD process (while taking into account drilling filtration invasion, mud cake, and permanent formation damage) and their impact on production under a variety of reservoir...

... to keep it in the well bore (a combination of the weight of the drill string and friction at the RCD) 1 . Figures 2 , 3 and 4 are pictorial illustrations of the amount and sheer size of the equipment currently used for UBD operations. When Shell took this technology offshore in 1997 basically...

..., it was demonstrated that the PIFs per well resulting from UBD would enable fewer wells to be used to develop the field by optimization of the horizontal well length and hence a significant reduction in capital expenditure. From these studies, two fields were selected to carry out initial trials. This paper describes...

... for a given UBD operation, are reviewed INTRODUCTION Underbalanceddrilling CUBD) is utilized with increasing frequency as a method to increase oil and gas well profitability by reducing invasive fornlation damage to maximize production rates, increase ROP to reduce drilling time and costs, and to obviate...

... functionality is provided by the BOPs. The complete UBD closed-loop flow control system comprises of the drill pipe (DP) circulating system, a UBD control device (UBD-CD), which provides the sealing mechanism around the drill string at surface, a UBD choke manifold (not the rig’s well control choke manifold...

... Abstract This paper speaks to offshore applications of specialized equipment developed for the practice of underbalanced drilling (UBD) where the intent is not to achieve a true state of underbalance at any point in a well's drilling program. The intent is not to produce hudrocarbons while...

... bottomhole pressure constraint Introduction The impact of damage and the need for its mitigation, remediation and/or elimination have received considerable attention in the literature as well as in drilling and production practice. Underbalanced Drilling (UBD) has emerged in recent times...

.... Underbalanced drilling (UBD) operations in this high-pour-point oil marginal reservoir, for two wells, SED-3 and SED-4, were planned to achieve the main goals of improving reservoir productivity, avoiding reservoir damage, enabling fracture identification, and making testing while drilling possible. Secondary...

... prevents flowing of HC's into wellbore after initial well completion especially in the depleted fractured Iranian reservoirs. Underbalanced drilling (UBD), with a reduced exerted pressure down in the wellbore avoids the build up small solids being deposited on the sides of the hole, it also prevents...