Dongpu Depression Deep Gas Reservoirs In The Research And Application Of Hydraulic Fracturing Technology

Deep formation in Dongpu sag has characteristics with high pressure and temperature, low porosity and permeability. Usually, the formation has to be stimulated in order to gain oil/gas production with industry standard. The major work in the thesis is as follow.(1) By gathering a lot of geology parameters, treatment parameters and hydraulically fracturing results, the relations between the fracturing effects and logging data was established, and standard of choosing goal layer was determined as 50. The non-linear model and successive regression model with multi-factors was gained, too, the main factors affected the results were pressure graduate, water-cut, effective permeability, proppant concentration and discharge.(2) The damage of the fracturing fluid to the payzone was evaluated. (1) The cake damage reduces the permeability about 20%, the damage of fracturing fluid with low interface and surface tension was less 58% than common fresh water. (2) Contrast to the pure water, the F_RCD of Tianjing gel (T) with 1024mg/L residue was low about 40%, and HPG gel with 309mg/L low about 17%.(3) Developed the HPG with low residual and good properties. (1) Its initial viscosity was high and only take 1hr to the highest viscosity. (2) The gel has good stability, the viscosity maintain same at 24hr and reduce about 20% at 72hr. (3) The properties could be kept at formation water with 8×10~4mg/L. (4) The residue was only 2.85%.(4) A new type of fracturing fluid with B cross-linker was determined. 2.0%HS-l clay stabilizer and HT—3B surfactant were firstly used. (1) Under 125~155℃ temperature condition, 2.0%HS-l is prior to 2%KC1. (2) The other properties was good.(5) F_RCD under 140℃ condition were tested. The change trend of F_RCD is similar to general temperature condition. The Frcd reduced about 90% when the close stress got down from 10MPa to 90MPa, and the Frcd of proppant with big diameter was higher; the FRCD of proppant with 100 mesh diameter was always less; The Frcd has a little something with sand concentration at high close stress condition.(6) Take well P67 for example, the phase station was simulated by PVT software package, and the relation of fracture length and F_RCD to production rate, GOR, pressure, and recovery percent of condensate oil was simulated by COMP IV components model. The optimum fracture length was about 200~300m and F_RCD about 30~50μm~2.cm.(7) Though fracture simulating by FracPT software, the fracture parameters were obtained by optimum pad-fluid ratio, treatment parameters and injection manner.(8) In order to successfully stimulate the formation, many technologies were used, such as stage proppant with different diameter, cleanup with chemical additive and forced fracture to close flow-back, linear increase sand concentration and injection from annular. And a good result wasgained by these techniques.