Experimental Study On The Boundary Of Development Technology Policy For Loose Sandstone Reservoirs Under Re-compaction

Unconsolidated sandstone heavy oil reservoirs play a very important role in the oil and gas resources in our country, this kind of oilfield reservoirs which have high crude oil viscosity, loose sand, low degree of cementation, and differential diagenesis were basically developed by waterflood. The re-compaction has a great influence on structure of the reservoirs'pore diameter and on the seepage characteristics when is not timely to inject water or formation pressure drop quickly, especially near the wellbore which has a pressure drop funnel area. And unconsolidated sandstone reservoirs that cementing strength is weak prone to sand production, so researching the oil well productivity under different re-compaction and sand production be of certain guiding significance to unconsolidated sandstone heavy oil reservoirs.In this paper,we developed the artificial unconsolidated sandstone cores according to the characteristics of unconsolidated sandstone, researching a set of weak cementation hypertonic loose sand core preparation technology,this kid of core do not need to broach and cover different level of unconsolidated sandstone permeability standard sample.And improved the experiment equipment, improving the multi-function displacement experiment equipment and testing physical parameters of unconsolidated sandstone under extremely low pressure difference.Using the heat shrinkable sleeve suit tool to protect the cores and using high precision digital pressure sensor to get pressure data. The system improved makes the highly automated multi-function and high-precision in displacement experiment equipment.Next,ev-aluated unconsolidated sandstone ordinary heavy oil reservoir productivity under different re-compaction and sand production, taking the multiple sets of experiments to study the heavy oil production capacity changes under different re-compaction of sand production. The experimental results show that, unconsolidated sandstone heavy oil reservoir productivity decreases with formation pressure decrease, and the range of productivity drop seriously less than 4 MPa.the reservoir is looser,the productivity drop is bigger.The effect under re-compaction gives priority to productivity index at low water content, the effect of sand production is relatively weak;there is a stage that increasing the permeability because of sand production, increased with the amount of sand production heavy oil production drop speed is slowed down under the condition of mid and high water content. The core is looser, the early stage of the water production rate is bigger, corresponding displacement output maximum differential pressure is 1.0-1.5MPa, the early stage of the water production rate is smaller, a maximum output corresponding displacement pressure difference of 2MPa.Finally,studied its reasonable production parameters for injection-production well.The development of unconsolidated sandstone heavy oil reservoirs need houding the pressure more than 11 MPa leveland adjusting to reservoir oil saturation pressure according to the well location.making the formation pressure above saturation pressure.Suizhong 36-1 oil field injection well reasonable injection pressure is 5.75-6.69MPa. Providing the experimental support from exp-eriment to theoretical certificationfor the loose sandstone heavy oilreservoir development tec- hnology policy research.