Sedimentary Characteristics And Distribution About Liu1Section Of The Huachang-bailian Region In Fushan Sag

Hainan Fushan Sag is a small basin with a high subsidence rate, a steep terrain, andquick changes of sedimentary facies belt in southeastern margin of Beibu Gulf Basin.Therefore the deep lacustrine and deltaic sediments of Liushagang formation are considerabledevelopment, but the sedimentary microfacies studies have not had substantive progress. Thestudy area is the Huachang-Bailian Region in the Eastern field of Fushan Sag, and the purposestrata is the member1of Liushagang Formation, the main reservoir of Fushan Oilfield.Studying the implementation of characteristics, distribution and lateral variations ofdepositional system in the study area of member1improves next drilling success rate inFushan Oilfield.On the basis of the results of previous studies, through the use of the principle ofsequence stratigraphy, the combination of the seismic and geological data, we have checkedand adjusted stratifications about all single well in study area, establishing a reasonableequities correlation framework and unifying of the region’s seismic geological stratification.The member1is divided into5sub-layers from the bottom up: the lower mud, the lower sand,the middle mud, the upper sand and the top mud. Upper and lower sandstone sections with themiddle and the top mud deposited more stable as a cap rock are two extremely favorable setsof reservoir in the member1of Liushagang Formation.Through the comparison of stratigraphic framework in study area, in accordance with theidea from the point to the line and then to the surface, the compared analysis of thesedimentary facies of the individual well and connection wells determines the the sedimentarymicrofacies characteristics of space and flat distribution in the study area. The type ofdeposition is the delta deposits of highstand systems tract (HST). And it is divided into ninekinds of microfacies: braided channels, floodplain, subaqueous distributary channels,interdistributary area, mouth bars, sheet sand, prodelta mud, slump turbidite fans andlacustrine mud. In study area there are three provenance directions: respectively northwestprovenance, southern and eastern provenance of Hua112x well field. The main provenancesare from the south and east, and the provenances have not spread to the large area, which is in a stable water environment, forming the deposit of lacustrine mudstone, to the direction ofHuadong Sag.Comprehensive analysis indicated that the lower sandstone of the study area is generallybetter in the Eastern, which is the main zones in the next well deployment process; the area ofupper sandstone section away from the source region on the west is much better, which arethe part-probe fields or prospects.