Compound Salt Drilling Fluid Technology Research And Application For Jia-3 Block Of Gaojiapu Oilfield

Drilling the salt-gypsum layer is a worldwide technical problem, although the salt-gypsum layer is not the main purpose of the oil and gas drilling, it is the good cover at the top of oil and gas layer, below the thick salt-gypsum layer tend to contain a large oil and gas field, drill through the thick salt-gypsum layer successfully and can keep wellbore stability for a longer period is one of the drilling completion problems.Jia-3 Block of Jizhong Gaojiapu Oilfield is one of the main producing region of Huabei Oilfield production increase. But in this fault block the oil and gas is buried deep, the geological structure is complex, multiple faults are contained. And the lower part of Shahejie formation contain a large section of the salt-gypsum layer. The wells drilled in this block have appeared in different degrees well collapsed, lost circulation, hole shrinkage, logging blocked,such as complicated conditions in Shahejie formation. Reaming, back reaming and expanding long reaming phenomenon appeared frequently, even jammed complex accident appeared in the process of drilling and reaming drill, the drilling cycle is long, commonly 2 to 3 months,the drilling cost is high and severely restrict the efficient development of the Jia-3 block oil and gas fields, leading to the fault block has not been put into development in an all-round way since its discovery in 1995.On the basis of extensive investigation, carry out experimental study of wellbore instability mechanism of Jia-3 Block of Gaojiapu Oilfield. Use "multiple synergy" basic principle of collapse prevention to select the suitable drilling fluid formula for field application. According to field test problems arising from the continuous improvement, form a set of more mature compound salt drilling fluid system. And develop a set of drilling fluid technology suitable to this fault block field construction template applied in the field.