Laboratory Investigation of Polymer Producer TU-15A for MEOR Field Tests

摘要

Clostridium sp. TU-15A was isolated from the reservoir waterrnfrom China jilin oil field. This microbe is a powerful polymerrnproducer and expected for the effect on oil recovery.rnThis is the fundamental study on this microbe for the fieldrntrial and consists of following two experiments.rnAt first, cultivation experiments were carried out with TU-rn15A. This microbe reaches maximum phase at a day andrnincreasing viscosity of the culture starts on second day. Thisrnresult shows that the culture needs to be injected into reservoirrnwithin two days after inoculation. The relation betweenrnmolasses concentration and the viscosity of this culture, whichrnis pseudoplastic fluid is linear: about 40cP (at 10r.p.m) atrnmolasses 4% and about 25cP at molasses 2%. From this result,rnit is possible to control the viscosity in reservoir. Andrnadaptability to the environment in oil reservoir wasrninvestigated with following two incubation systems: microporernsystem and competition with indigenous microorganisms.rnTU-15A grew and produced polymer even under thesernconditions and there is not serious problem for cultivation inrnreservoir. In the examination with micro-pore system, thisrnmicrobe grew slowly and reached maximum phase at forthrnday. This is an effective result for spread of culture inrnreservoir. In competition test with indigenous microorganisms,rnwhich were sampled from one block in Jilin oil field, thernviscosity of this culture became low. Therefore it is necessaryrnfor TU-15A to test competition with indigenousrnmicroorganisms in selected target blocks again.rnSecondly, flooding experiments were carried out withrnviscous culture of TU-15A with following two systems whichrnwere modeled with two sandpacks. One was five spot floodingrnpattern and the other was anisotropy of permeability. At thernformer experiment, two sandpacks total oil recovery was 73%rnafter water flood and 12% of initial oil saturation after thernculture injection. In the case of latter, two sandpacks total oilrnrecovery was 68% after water flood and 15% of initial oilrnsaturation after the culture injection. In both cases, high oilrnrecovery were obtained from flow smaller sandpack and thernchange of flow caused these results by the culture injection. Atrnthe five spot flooding pattern, flow of injected fluid to flowrnsmaller one improved from 22% at water flood to 47%:rnmaximum of 56% and minimum of 38% and at the anisotropyrnof permeability, flow improved from 7% at water flood torn21%: maximum of 34% and minimum of 16% by injectionrnculture. Moreover, the viscosity of culture was changed withrntwo kinds of microbes in these experiments.rnJilin oilfield has an anisotropy of permeability and greatrneffect is expected on oil recovery in this field with TU-15Arnfrom these results.