Determination of well spacing volumetric factor for assessment of final oil recovery in reservoirs developed by horizontal wells

The formula for determination of volumetric factor of well spacing for assessment of final oil recovery in reservoirs developed by horizontal wells is offered. For the purpose of comparison of well spacing calculated using conventional and volumetric techniques, twelve development options of the pilot area of the Yamashinskoye field with variousplacement of vertical and horizontal wells were considered. By results of calculations, marked difference in values of well spacing was observed testifying that the conventional formula used to calculate well spacing does not consider the volume nature of fluid inflow to wells with one or more horizontal laterals. The offered technique of volumetric determination of well spacing through the inclination angle, the radius of well drainage area, and the length of a lateral considers the volumetric nature of inflow to horizontal multilateral wells.

Redox-Reaction Products Of 4-Sulfo-2-(4'-Sulfonaphthalene-1'-Azo) Naphthol-1 With Ce(IV) - New Analytical Forms For Its Quantitative Determination

The results of redox interaction of Ce (IV) with 4-sulfo-2-(4’-sulfonaphthalene-1’-azo) naphthol-1 (carmosine- KAN) in aqueous solutions (pH 1.75) have been presented. The destructive oxidation of CAS into two fragments (2-nitroso-4-sulfonaphthol-1 (L1) and 1-nitroso-4-sulfonaphthalene (L2)) is accampanied by reduction of Ce(IV) to Ce(III). It was found that an increase in the Ce(III) -L1 -L2 system acidity to pH ~ 11 leads to formation of the [Ce(III)(ОН)2·L1·2Н2О] complex. After acetonitrile is introduced to [Ce(III)(ОН)2·L1 ·2Н2О] – L2 system (up to 40 % by volume) self-organization of products involving CH3CN is observed. The resulting water-acetonitrile system becomes turbid, and after ~10 min phase separation is observed. Phase I contains a solvate {L2·(CH3CN)п } of «straw» color (360 nm) and phase II (lower layer) contains solvated complex {[Ce (III) (ОН) 2 ·L 1 ·(CH 3 CN) 2 ]·(CH 3 CN)n} of «blue» color (640 nm). The use of these solvates allows determination of Ce(IV) in the range 2.2 ч 50.1 μg/cm3 (y = 0.5526с + 0.0575, R2 = 0.9917, ε360 = 6.2·103) and 4.2 ч 84.0 μg/cm3 (y = 0.1862c + 0.0265, R2 = 0.9952, ε640 = 2.05·103), respectively. The revealed dependence was used for indirect (volumetric) determination of Ce(IV) (y = -0.7857c + 20.4440, R2=0.9988). The methods was tested on standard samples of mineral origin and herbal pharmaceutical preparations.

The use of Spectroquant Merck BOD photometric test to evaluate the stabilityof organic matters in soil

We proposed a new method to determine the rate constant of biochemical oxidation of soil organic matters that makes it possible to evaluate their stability by Spectroquant Merck BOD photometric tests; if smaller samplings are used and individual determinations are performed, it can replace the method of BOD vacuum measuring by an Oxi Top Control Merck system. The time and labour consumption of this vacuum method is sometimes criticised, but it has demonstrable work advantages for a large series of samples and so it is still recommended. The two methods are identical as for the correctness and coincidence of results and they do not differ by either lower or higher results and therefore we recommend the new method with photometric tests for smaller series of samples. For the high time and labour consumption we must warn against the use of traditional BOD dilution method with volumetric determination of oxygen for the determination of rate constants.