Research On Logging Detection Technology Of Horizontal Well Cracks

Gansu Huachi Chang 4+5,6 low porosity and low permeability tight sandstone reservoirs, are generally used horizontal well perforating fracturing ways to enhance oil recovery. Therefore, the effective horizontal well logging fracture pressure detection technology plays an important role, including pressure fracture location, extension status, high seam slit width calculation. Currently, the horizontal well pressure crack logging detection techniques commonly used are between Cross well micro seismic and dipole shear logging, but because of inter-well micro-seismic construction is complicated and costly, not large-scale application; DSI instrument Dimensions Length (51 ft), in hole section after the instrument decentralization process pressure and put on easily blocked, causing the instrument buried down, bring greater economic losses, there is an urgent need to work out an effective horizontal well logging data based on pressure crack detection method.To accurate understand the influence law of types of ground stress on shale gas horizontal well orientation can effectively prevent borehole sloughing control, saving the drilling cost.Based on field logging data of shale gas horizontal well-through analyzing rock mechanics log interpretation results of shale gas horizontal well in the different types of ground stress, the influence law of types of ground stress on shale gas horizontal well borehole stability was come out in this paper. In order to achieve the horizontal wellbore stability in the process of hale gas drilling, shale gas horizontal section of the wellbore trajectory azimuth selection principle was proposed. The clip angle of the optimal orientation of horizontal well trajectory segment to the maximum horizontal ground stress direction corresponds to the normal ground stress, slip ground stress, inverted ground stress were 90o,45o and Oo, respectively.After the Horizontal wells casing cementing, Perforating pressure cracks are generally transverse crackings. At present, the domestic lack of testing and sonic logging method for evaluating the casing horizontal well perforating pressure cracks. CBL, VDL, SBT and other traditional sonic logging methods are often used to detect acoustic quality cementing between the first and second interface, in fact, VDL full wave also contains a wealth of information about the formation wave can be used to identify the laminated cracks. In this paper, based on this idea, launched VDL horizontal well pressure response chracteristics of fracture simulation experiments. Focus on the formation wave P-wave, S wave and ST wave of horizontal well fracture pressure response characteristics, designed to provide theoretical guidance and experimental basis for the implementation of horizontal well casing perforation after fracturing sonic logging project oil field. Research results and achieved the following understanding:(1) completed horizontal well fracturing fracture VDL recognition experiments (in total 45), successfully observed P, S spread their pressure cracks in horizontal wells response characteristics.(2) successfully developed a test waveform data conversion EXCEL file format for WIS data conversion software tools, based on the use ConvertGUI WIS converted files and then convert GDS data software, and finally with the solid LEAD wells in the detection module processes this GDS data obtained VDL variable density maps, according to this figure can be a good pair of pressure fracture identification.(3) by experiment the VDL horizontal well fracture pressure response characteristics to extract sensitive parameter identification horizontal well pressure cracks, summed up based on the horizontal wellbore trajectory and stress orientation angle between the longitudinal compression fractures and identify lateral pressure the method of cracks.(4)establishment of a horizontal well pressure slit width of cracks, fracture height and fracture length calculation model, mapping display and the corresponding programming.(5)completed the VDL actual measurement site of a well, which the measurement data processing and analysis.Through the above experiments and data processing, to final mapping shows that the formation of a horizontal well logging data set based on VDL pressure fracture identification detection technology. Logging on-site practical production applications and achieved good results and greatly reduce the cost of logging.