Theory And Research Of Reducing Reservoir Abnormal Burst Pressure

The exploration area of China's unconventional hydrocarbon resources is so amplitude that the prospect of resourse gose far beyond current conventional petroleum resource. Developing this kind of tough reservoir in a safety and high efficient way is significant for both China's steady development of petroleum industry and petroleum security . There is a increasingly comprehensive attention on fracture which is applied to the reservoir. However, because fracture in this type of well is still at the primary stage,it still has some localization in technically, such as compact reservoir rock, Young's modulus,tensile strength,high layer shut-in pressure and severe pollution. In order to conduct a deep penetrating large-scaled sandfrac, the well intake pressure is so high even exceed the design requirement that we have to terminate construction, as a result,there will be a big waste of human and material resource. This article that focuses on the systematic and in-depth research in the current primal problem about abnormal burst pressure reservoir depress burst pressure has procured following main fruits:1) It forms the method which could obtain massive vertical static state mechanics parameters.2) In a foundation of acquisition of rock mechanics parameters,apply bent lamella that as mechanical model along with characteristic of actual geologic characteristics to analysis curvature for anticlinal strcture, get homologous tectonic stress value throug relation between the curvature and stress and different principal curvature in anticlinal structure,consequently set up laminational stress model for anticline reservoir. The block lamination for existed fracturing date has formed method of setting up mechanical model of lamination terrestrial stress by abtaining the block tectonic stress coefficients which are got by complex utilization test, laboratory test and fracturing date playback.3) Analysesing the main reason which lead to high burst pressure by considering the characteristic of reservoir geology,reservoir,and rock mechanics and reservoir damage,etc.Establishing burst pressure quantitative prediction model which provide gist for depressing construction risk and optimizing construction craft under the condition of open hole completion ,gun-perforated completion and damaged reservoir.4) Provding theoretical basis for interpreting acidification pretreatment which could depress busrt pressure by finding the relation between the influencing factors and rock machanics parameters and analysing the factors that have effect on rock mechanics parameters. Expounding the mechanism of reaction of mixed monomineral and acid from the angle of microcosmic element, evaluating quantitatively acid sensilility of different kinds of mineral effectively, and determing the first-order reaction dynamical equation of each mineral.5) Revealing rock mechanics property chage as a result of acid flooding in different condition by sandstone traumata experiment in different temperatures which combined with rock mechanics triaxial stress experiment.6) Associating damage mechanics with sandstone acidizing, established sandstone damage mechanics model in the foundation of the recognition on the rock mechanics parametric variation which is caused by acid-rock reaction in both macroscopic view and microscopic view ,also demonstrated those processes and quantitative estimated the acid busrt pressure to direct the site operation.