Study Of High Wellhead Pressure And Technical Limits In Single-pipe Concatenation Gathering&Transportation

As oilfield development entering into high water cut stage, tertiary oil recoverytechnique is applied in the oilfield, it is vitally important to adjust the corresponding oilgathering system technical parameters and widely generalize the simplified single-pipe oilgathering process. In order to optimize the gathering system and reduce the energyconsumption in the production, single-pipe concatenation process has been widely designed,researched and applied in oilfield ground engineering practice, and the effect is obvious.However, during the operation of the process, lots of problems are appeared, such as oilgelling in gathering pipelines and obvious increase of the high wellhead pressure wells,leading to serious wax precipitation in gathering pipelines, the system pressure rise up andfrequent washing of pipelines in regular production management. These problems causepotential safety hazard and directly influence high-efficient development and regularproduction in oilfield.Therefore, taking Daqing Sabei Oilfield as research object, the highwellhead pressure and technical limits in single-pipe concatenation gathering&transportation are studied.According to the viscosity and viscoelasticity of the system, temperature limits andpeak temperature ranges of gelling oil formation are determined. Combining coolingtransportation laboratory tests and establishment of wax deposition dynamical model,gelling oil formation and wax deposition law in single-pipe concatenation transportation aresystematic studied and predicted. The results indicate, in different working conditions, thepredicted values of deposition rate by using wax deposition dynamical model can bettermatch the test results, and mean relative deviation is about10%. Then, based on single-pipeconcatenation oil gathering technological adaptability field test, high wellhead pressureproduction materials and the determined gelling temperature limits, high wellhead pressureand its characteristics are comprehensive compared and analyzed. In the end, the gathering&transportation limits of252single-pipe concatenation wells in Daqing Sabei Oilfield areoptimized, and the minimum transportation flow limits and the lowest temperature limit ofwell mouths are determined in different working conditions.