Water flooding is the hinge pin for Petrobel Oil Field. Water injection is supplied from shallow water supply wells. Compatibility tests, Petrographic Techniquesand quantitative calculations of scale tendency using specific softwarehad indicated probable deposition of calcium sulphate scale in the near-wellbore (Critical Matrix). Calcium sulphate scale, paraffin & was have been recognized to be a major operational problem. The bad consequences of scale formation& organic deposits comprised the contribution to flow restriction thus resulting in oil and gas production decrease. The nature of calcium sulphate scale is very hard and can't be dissolved with known dissolver. Sister companies that has similar problem were always going to the mechanical remover options which usually lead to further formation damage when invasion of formation rock by small particle sizes of the scale components.Extensive lab and field work was conducted to determine the suitable chemicals to dissolve calcium sulphate scale.The Production of Sidri formation which is currently contained 23 % of belayim land field OOIP (original oil in place) and currently contributes 27 % to the total oil production has been stopped dramatically in some wells.Sidri formation exhibits a high degree of permeability, heterogeneity and increase water injection was done in some areas that lead to increase the possibility of forming scale, most of scale in Belayim onshore is calcium sulphate.Precipitation of mixed organic/inorganic deposits (Calcium Sulfate Scale) resulted in decreasing the permeability in the critical matrix and perforation tunnels. Scale formed in the near-wellbore reduces oil production by blocking the narrow pore throats of the matrix itself This paper highlights Petrobel first application by using the new innovation product SCSR in Belayim land field (Sidri formation), its success and results based on extensive lab studies, SCSR was tested and applied through an effective treatment strategy proposed to remove the scale efficiently; the program was designed taking into consideration the nature of the scale. Furthermore the proposed treatments were conducted and placed using coiled tubing (CT).

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One of the major challenges in Abu Dhabi onshore oil fields is the substantial increased water production with time. This is mainly attributed to unforeseen the presence of sub seismic faults and fractures along the drain hole. To address this, smart completions are being introduced to control water production by moderating the flow profile across the completed interval, whereby water and gas breakthrough are delayed in producing wells and injection rates are optimized in water and gas injectors across the full wellbore face. The smart completion design is supported by dynamic and static reservoir information. In this study, production logging tool (PLT) data was available to benchmark and confirm the results from dynamic simulation modeling. However, geologic features that cause the uncontrolled water inflow were not confirmed due to lack of lack of image data.A novel methodology has been implemented allowing resistivity image acquisition in workover wells by utilizing a compact memory tool that addresses the challenge of accessing old wells in Abu Dhabi onshore oil fields. The poor condition of the well is a result of prolonged production, post-stimulation and subsequent borehole degradation. The technique consists of acquiring data using drill pipe with significant savings in rig time and a higher chance of accessibility when compared to alternative techniques. This technique also protects the tool from becoming stuck and incurring damage during entry, thus improving data acquisition quality and minimizing the possibility of re-runs. When compared with common pipe-conveyed wireline alternatives (TLC) in previous wells, up to 33% savings in logging time was observed with a much safer operation.The procedure was achieved with success in terms of image data quality and execution time. In the absence of core data, the microresistivity imaging technique gives the best possible picture of the rock. It has been effective in characterizing rock fabric required for structural analysis (including fracture identification and fault identification and analysis), geomechanics, sedimentology (including paleocurrents analysis and facies determination) and image petrophysics applications such as identifying vuggy secondary porosity. A quick-turnaround in data processing allows the introduction of detailed fractures and fault interpretation, which in turn allows optimization of the completion design.

Landing a high-angle well in the very thin carbonate reservoir of the lower Cretaceous can be challenging due to heterogeneity present in thin layers above the reservoir and lack of correlatable non-porosity measurements. The use of radioactive source porosity is effective, but due to the extended trajectory and high differential pressure in over burden depleted reservoirs, the chance of becoming stuck is a considerable risk and a big concern, and thus the use of classic nuclear porosity tools are untenable. This paper is a case study illustrating the use of azimuthal sonic porosity as a highly effective method of landing the well in the reservoir.Azimuthal sonic data were acquired with a focused unipole tool which recorded the measured waveforms and computed compressional and shear velocities in 16 azimuthal bins. Real-time compressional and shear slownesses were also computed by stacking all 16 bins of data, which gave very high signal-to-noise ratios and excellent data quality -often a challenge in hard formations. These azimuthally averaged slownesses were used by the geologist to identify formation tops while drilling, and to detect the approach of the target reservoir, resulting in a safe landing in the target zone.While the azimuthally averaged real-time sonic porosities were effectively used to land in the target reservoir, the azimuthal results were examined shortly after the well was drilled to understand the additional advantages of using the azimuthal sonic porosities real-time to detect approaching beds from further away. It is clear from the results that, if the porosities from each quadrant (or even just up and down) were transmitted real-time, the reservoir could be detected an additional 1.5 ft. away (TVD). The hardware has since been modified to apply this approach, allowing for 4 quadrants of sonic compressional and shear slownesses to be transmitted in real-time to enhance the detection range. The technology has been applied in real time in the second well with success. It was proven this extended depth of detection can add an additional safety margin to enable landing the well in the reservoir at the optimal angle. Due to the higher depth of investigation the landing can further be optimized using the bottom quadrant slowness, allowing for the early detection of the soft porous layer well before penetrating it.These quadrant sonic values can be used in existing geosteering workflows to enhance the ability to detect formations, particularly when other measurements such as resistivity or gamma ray yield very shallow depths of detection due to poor formation contrast or depth of detection of the measurements. This case study builds upon previous sonic experience by investigating the range of azimuthally binned measurements versus azimuthally averaged results and shows a most convincing example illustrating the effectiveness of the method in an Abu Dhabi formation.

UAE environmental regulations call for minimizing exposure to radioactive waste while drilling. In depleted carbonate reservoirs, the low radiation energy, short half-life Californium-252 (Cf-252) neutron source provides a "fit for purpose" replacement to the high radiation energy, long half-life americium-beryllium (Am-Be) neutron source. With the much shorter half-life time Cf-252 neutron source, ADCO could minimize the associated liability of getting stuck downhole by eliminating the use of high energy radioactive sources with 430 year half-lives. The Cf-252 sources emit neutrons as a result of spontaneous fission with a probability of about 3%. One gram of Cf-252 yields about 1,012 neutrons per second (n/s), which is a much higher neutron yield than Am-Be sources. A typical Cf-252 source with an activity rating of 20 mCi emits about 108 n/s compared to 16 CI from Am-Be. This fission reaction has a half-life of 2.6 years compared to 430 years for Am-Be, which means that the neutron output of the source drops by a factor of two every 2.6 years. However this reduces the useful life of the source to somewhere between 5 and 10 years. Although higher-output Cf-252 sources can be obtained to lengthen the useful life of the source, cost and safety may be issues. To prove the effectiveness of the new source, it was decided to run the Cf-252 back-to-back with the Am-Be source. By running both sources in the same bottomhole assembly (BHA), the quality of the Cf 252 could be validated by comparing the back-to-back measurements generated from both Cf-252 and Am-Be sources. The data was compared while wiping in, wiping out, and drilling. The Cf-252 source tool was placed on the top of all other tools in the BHA in recorded memory mode. The data acquired while drilling showed a slight separation between Cf-252 porosity readings and the readings from the tool using an Am-Be. This is due to the varying formation exposure time experienced by the tool with the Cf-252 source, an invasion effect observed due to the slow rate of penetration (ROP). There is also much closer agreement between the two neutron measurements while wiping out. This case study demonstrates the value of using a low radiation energy Cf-252 source compared to using high radiation energy Am-Be source when drilling in a depleted reservoir. A lost-in-hole Am-Be source had to be fished, which prevented the operator from plugging the well. However, using a Cf-252 source would minimize such liabilities, making the plug back procedure easier with significant savings in time and money.