Bhagyam Full Field Polymer Flood: Implementation and Initial Production Response

Bhagyam is an onshore field in the Barmer basin, located in the state of Rajasthan in Western India. Fatehgarh Formation is the main producing unit, comprising of multi-storied fluvial sandstones. Reservoir quality is excellent with permeability in the range of 1 to 10 Darcy and porosity in the range of 25-30%. The crude is moderately viscous (15 – 500 cP) having a large variation with depth (15 cP – 50 cP from around 270 m TVDSS to 400 m TVDSS and then rising steeply to 500 cp at the OWC of 448m TVDSS). Lab studies on Bhagyam cores show that the reservoir is primarily oil wet in nature. Bhagyam Field was developed initially with edge water injection and with subsequent infill campaigns, prior to polymer flood development plan implementation, the Field was operating with 162 wells. Simple mobility ratio and fractional flow considerations indicate that improving the mobility ratio (water flood end-point mobility ratio is 30-100) in Bhagyam would substantially improve the sweep efficiency. Early EOR screening studies recommended chemical EOR (polymer and ASP flood) as the most suitable method for maximizing oil recovery. The lab studies further demonstrated good recovery potential for Polymer flood. Bhagyam's first Polymer flood field application started with testing in one injector which was later expanded to 8 wells. Extended polymer injection in these wells continued for four years. Observing a very encouraging field response, field scale polymer expansion plan was designed which included drilling of 28 new infill wells (17 P+ 11 I) and 24 producer-to-injector conversions. Modular skid-based polymer preparation units were installed to meet the injection requirements of the expansion plan. Infill producers were brought online in 2018 as per the plan but polymer injection was delayed due to various external factors. The production rate, however, was sustained without significant decline, aided by continuous polymer injection in initial 8 injectors, continuing water flood and good reservoir management practices. First polymer injection in field scale expansion started in Oct’20 and was quickly ramped up to the planned 80000 BPD in 4 months, supported by analyses of surveillance data, indicating very encouraging initial production response. Laboratory quality check program was designed to check quality of polymer during preparation and to ensure viscosity integrity till the well head. The paper discusses modular polymer preparation unit set-up and the additional installations designed to reduce pipeline vibrations during pumping of polymers., Experience gained while bringing online the polymer injection wells and the lab quality checks employed to ensure good polymer quality during preparation and pumping have also been discussed. The paper also discusses reservoir surveillance program adopted at the start of polymer injection like spinner survey, Pressure fall-off surveys and the stimulation activities that worked in improving the injectivity of polymer injectors. The paper further outlines the observations from the production response and the surveillance data collected to ensure good polymer flow in this multi-darcy reservoir.

EOR Steam Injection Huff and Puff Method: An Analysis of Production Response in Low Performance Well

Steam Injection Huff and Puff is one of the EOR methods by injecting heat energy in the steam phase to reduce oil viscosity and reproducing oil in the same well. The geological structure of this field is a complex-faulted anticline that compartmentalized the field into five blocks with two potential blocks for EOR Steam Injection Huff and Puff Method. The oil properties are categorized as heavy oil because of high viscosity, high pour point, high congealing point, and low API degree. Therefore, the Recovery Factor (RF) only reaches 14% with EOR method. Screening criteria is conducted for selecting well candidate with low performance. It means the well with oil temperature <110 oF and flow rate <20 BOPD. EOR Steam Injection Huff and Puff Method consists of three stages such as injection period, soaking period and production period. The steam design becomes a reference in determining the duration of each stage. The duration of EOR Steam Injection Huff and Puff Method has been estimated for a total of 20 days with 11 days for injection period and 9 days for soaking period. There are three parameters used to analyze the production response after EOR Steam Injection such as Productivity Index (PI), Inflow Performance Relationship (IPR) Curve, and Production Rate Test (PRT). These parameters show the comparison before and after EOR Steam Injection. Based on these three parameters, EOR Steam Injection Huff and Puff Method has successfully improved 76% of oil production in this well. This study concludes that there are four critical factors for the success of EOR Steam Injection using Huff and Puff Method, and will be described explicitly in this paper.

Photostimulated changes in egg production and reproductive performance of the Guinea fowl in a sub-humid tropical environment.

The effect of photo-induced changes on egg production and reproductive performance of female guinea fowl was studied by exposing the birds to three photo-regimens, namely natural daylight all day for 12 weeks (NDL), 8 hours of light per day for 8 weeks (8L-16D) plus supplementary light for 16 hours per day for 4 weeks (16L-8D) (RSL), and provided natural daylight all day for 8 weeks plus supplementary light at 16 hours per day for 4 weeks (SL). Weight gain during the pre-laying period was similar (P>0.05) in all the treatment groups between 20-36 weeks of age. The reverse was the case during the laying period between 36-52 weeks, which coincided with the age at sexual maturity. Feed intake was similar (P>0.05) for the NDL and SL groups during the pre-laying period but the RSL group had significantly lower (P<0.05) feed intake than the others. Overall laying mortality was lowest in the RSL birds. There was no significant difference (P>0.05) in body weight for all the groups. Age at first egg was significantly lower (P<0.05) in the RSL (207 d) than in the NDL (249 d) and SL (235 d) birds which were similar (P>0.05). The guinea fowls which received 8 weeks of restricted light (RSL) responded more rapidly in terms of day-to-first-egg after exposure to 16 hours of light and achieved significantly higher (P<0.05) level of egg production than the other two groups. The overall economy of production, in terms of cost, revealed that RSL birds performed better than the NDL and SL, in that it cost N36.58 and 127.05 more to produce each NDL and SL guinea fowl at point of lay respectively. The results indicate that different light regimes altered the time during which egg production response took place and apparently affected the genetic potentials of the groups with regard to egg mass and total number of eggs laid during the period covered by this trial.

148 Superovulation and embryo production response in oestrus-synchronized Arunachali yak

The Arunachali breed of yak is reared by the Monpa pastoral community of Arunachal Pradesh in India for their livelihood and nutritional security on highland pastures. In addition to fulfilling the basic needs of highlanders, this animal is associated with poor production potential linked to its inherent reproductive problems, including silent oestrus, seasonality, and inbreeding, making yak rearing a less-profitable venture. In the recent past, efforts have been made to improve reproductive efficiency of Arunachali yak through assisted reproductive techniques. However, a few regimens for superovulation have been tried to date with limited success in terms of superovulatory response and embryo recovery. Therefore, the present study was undertaken to evaluate the efficacy of two different doses and regimes of superovulation: Stimufol (400 and 200µg per animal) and Folligon (1500 and 1000IU per animal) in Arunachali yak. Twenty-four yaks were allotted in 4 groups (of 6 animals each) and subjected to respective superovulation treatment. Thereafter, the treatment response was assessed in terms of expression of oestrus, interval between treatment and oestrus onset, duration of oestrous, number of corpora lutea and embryos recovered, and analysed using two-way statistical analysis between treatment groups. The results (Table 1) showed a significant (P&lt;0.01) variation in onset of oestrus after the treatment, whereas other responses did not differ among the groups. Further, the recovered embryos were categorized as excellent, good, fair, and poor according to cell size, shape, texture, and number of vesicles present in the blastomeres; 58.33, 20.83, 8.33, and 12.5% embryos in these categories were recovered, respectively. The overall embryo recovery rate was 30.77%, ranging from 10.53 to 52.38% in different treatment groups. The numbers of embryos recorded were less than the numbers of CL present, showing the possibility of non-availability of all ovulated oocytes for fertilization in the oviduct due to untrapping by the fimbriae. The effectiveness of treatments depended upon the precision of oestrus detection and the time of ovulation. In our study, the variation in onset of oestrus might be associated with poor expression of behavioural oestrus in the treated animals. Based on the present findings, we conclude that all the treatments are effective in superovulation and embryo recovery. However, the use of Folligon at 1500IU seemed to be comparatively more effective in Arunachali yak. Table 1. Mean (n=6) average of treatment responses in yak following different superovulatory treatment Variable Treatment Stimufol Folligon 400 µg/animal 200 µg/animal 1500 IU/animal 1000 IU/animal Oestrus response (%) 100 100 100 100 Interval between treatment and oestrus onset (h) 17.67±0.56a 20.83±0.79b 21.17±0.79bc 23.67±1.43c Duration of oestrous (h) 30.33±1.09 28.50±0.99 31.50±1.50 28.83±1.25 Corpora lutea (n) 2.83±1.22 3.50±1.18 3.50±0.67 3.17±0.87 Embryo recovered (n) 0.83±0.83 1.00±0.81 1.83±0.98 0.33±0.21 Recovery rate (%) 29.41 28.57 52.38 10.53 a–cMeans within a row with different superscripts differ P&lt;0.05.

Ration formulation.

This chapter describes a method of calculating the combination of feed ingredients which will give a mixture which contains nutrients in specified concentrations. If these concentrations are similar to the animal's nutrient requirements, then it can be fed to obtain the expected production response. To correctly formulate a ration, data which is presented in a consistent manner, and is appropriate for the type of animal the ration is intended for are needed.