Application Of Subtle Reservoir Description In HorizontalWells Exploitation

Horizontal wells have a good effect in exploiting remaining oil in old oilfield. Theyare also effectively in enhancing oil recovery of some reservoirs in which oil is hard to beextracted. For allocating horizontal wells, the first we should do is describing targetreservoir subtly. This paper introduced the horizontal wells exploitation in LaoyemiaoOilfield. We took the seismic subtle interpretation as major, combining the geologycharacter, logging and drilling data to describe target reservoir. According to the results ofdescription located horizontal wells in the reservoir. In this book, we used many differentmethods to interpret seismic data to fulfill the subtle interpretation demand of horizontalwells. Based the interpretation results, sand spread and oil area were showed. According tothe information the structural map was plotted and located horizontal wells.This paper research allocation of horizontal wells from follow aspects:Introduced seismic acquisition and process simply. From analysis, we could see thatthe seismic data which was interpreted for locating horizontal wells had high resolution.We could obtain high precision geological model from it.Illustrated subtle structure interpretation from two aspects which included faultsinterpretation and horizons interpretation. Faults position is very important to locatehorizontal wells. In this paper, we interpreted faults with seven methods. The doublecoherent correlated function which is one of these methods was programmed. This methodinterpreted the being of minor faults and located the fault point position effectively. Whenwe interpreted horizons, we amplified waveform to track, which could decrease the errorcaused by interpreter.Sparse spike inversion was used for tracking sand. When seismic data have highresolution, it is effectively to inverse sand of both multi-well area and no-well area. In thispaper, we took two areas as for example. There was a lot of log data in one area, andanother lacked it. By sparse spike inversion method, the target sand distribution is showedon us. It provides accord for plotting structure maps and designing horizontal wells targetpoints.Extracted seismic attribute to predict reservoir. In this paper we extracted forty-three kinds of attributes by SAIS software. We clustered these attributes and analyzed sensibilityof different parameters responded to different attributes. From this analysis, some attributeswere picked out to predict parameters, such as porosity and oiliness. Three predictedmethods were used in this paper. They were Multiple Stepwise Regression Analysismethod, Neural Network method and Non-parameters Regression Analysis method.Contrasted results obtained by three methods, it showed that the predicted effect analyzedby Non-parameters Regression Analysis method was the best. The predict result wascoincided with the result obtained from log data and experience. This result was used forhorizontal well target allocating.Took two areas in Laoyemiao Oilfield for example. We combined seismicinterpretation results with deposition character, structural feature, log data and produceddata to fix area with gas and oil. After these works, structural maps of oil layer superfacewere plotted. According to the maps the horizontal wells were located. There was one ofdesigned horizontal wells to be put into production, which produce is more thanconventional controlled directional well. The result confirmed that subtle reservoirdescription technology which took the seismic interpretation as major could direct thelocating and producing of horizontal wells effectively.