Search

The balance relationship between bottom hole annulus pressure and formation pressure is a key factor to affect the drilling operation safety. Because of the complex and various situation underground, there is a big error between the actual bottomhole pressure and calculated one. The paper introduced a PWD system which can measure the parameters of weight on bit (WOB), torque, annulus pressure, annulus temperature, pressure inside the drill string, etc., and transmit the measurement data to the ground in real time. With the real time measurement data, the wellbore hydraulic model can be corrected in real time, and the underground situation can be interpreted in real time, what is more, the drilling accident can be predicted in real time. The field test proves the accuracy and reliability of the measurement system. Compared with the storage PWD system, this measurement system is more accurate, and has the function of transmitting the measured data in real time, so it can offer powerful technical support for drilling operation. [ABSTRACT FROM AUTHOR]

The stick-slip phenomenon is very common in downhole drilling process. It is harmful for drilling project and could damage downhole devices, and even brings about dowmhole accident, which is a threat for downhole safety. So it is significant to timely find and remove stick-slip for drilling operation. Domestic drilling contractors and surface logging companies have attempted to study and predict stick-slip phenomenon at downhole by monitor the driver motor current and rotary table torque. The paper provides a new method to describe the downhole stick-slip phenomenon by measuring actual rotational speed of the lower BHA from MWD magnetic sensor, which give a better insight to the downhole drillstring movement, and classifies the severity of stick-slip to several ranks. The information is send to the surface by MWD so that the driller can take some useful manners to decrease the stick-slip and keep drilling process in safety. [ABSTRACT FROM AUTHOR]

The conventional weighting admixture of ultra-high density water-based drilling fluid may lead to viscosity effects, which means that the drilling fluid could lose its flow property due to high viscosity. In this paper the properties of barite optimized by using surface activation and particle classification. First the optimum dosage of surfactant (RAB) was determined after experiments of electric potential effect and rhelogy behavior; furthermore, on the basis of classical accumulation theory and plenty of laboratory experiments, the particle size ranges under different modulus and the optimum particle classification were calculated by using the distribution equation of Dinger-Funk. An industrial specific barite was produced by adjusting and optimizing production process and then was applied into several deep wells with ultra-high pressure in Sichuan area. Finally, the ultra-high density water based drilling fluid (with the density of greater than or equal to 2.65 g/cm³) is successfully prepared on site. The applied results show that the ultra-high density water-based drilling fluid with special barite has characteristics of weighted high density, easy controlled rhelogy behavior, and anti-salt & water invasion resistant. It can satisfy the actual requirement of practical drilling operation, and thus worth popularizing. [ABSTRACT FROM AUTHOR]

Considering the practical production figures and block mechanism analysis of Well WAA-1, the coiled tubing acid washing measure for removing pollution is proposed, and then the operation background, project design, operation process as well as effect evaluation of coiled tubing acid washing treatment are illustrated in this paper. By adopting the way of tripping the coiled tubing and controlling the lift speed and injecting rate, the acidizing fluid can be distributed equally in the horizontal interval. While wash head impulse vibrate, it will produce pressure agitation to screen pipe to wash deeply and remove damage. [ABSTRACT FROM AUTHOR]

Honghe oilfield has the characteristics of low porosity, ultra-low permeability and natural fracture growth. Open-hole packer staged fracturing technology was mainly conducted in the early development stage, which is subjected to complex process of drilling sweep ball seat and difficult construction of secondary reformation. Through salvage sliding sleeve fracturing process test, the shaft diameter can be realized in whole wellbore, which provides technical support for the secondary transformation and interference factors analysis. The tube-string structure, technique characteristics and operation process of salvage tools were introduced in this paper, and pilot test was carried out in Well HH37P32. Field application shows that this fracturing technology can effectively implement stimulation for horizontal wells, and improve the fracturing effect of low permeability reservoir. [ABSTRACT FROM AUTHOR]

Such as side attrition of pumping rods and tubes problems often encountered when the conventional oil pumping unit is used for inclined wells production. To solve the technical problems, a new liquid power assisted rodless oil pumping system is developed based on hydraulic principle. The novel system can completely solve the rod-tube side attrition problem, and is especially applicable used in inclined wells. This system includes ground hydraulic driving system, power transmission system and down-hole hydraulic oil pumping system. Its workflow is introduced in this paper. In-site test has smoothly run over 18 months which indicates the system can fully meet the oil field production requirements. [ABSTRACT FROM AUTHOR]

Acid-cleaning technology of screen completion horizontal well is an effective measurement for cleaning the drilling fluid pollution in bore hole, and the acid-cleaning effect directly affects the well productivity. The early stage of acid-cleaning strings in Shengli oilfield has some deficiencies such as incompletely sealed well-washing valve, poor sealing effect of well washing packer and no drainage channels. Such problems directly caused poor acid-cleaning effect on horizontal wells. The acid-cleaning strings were specific modified and the sealing structure of washing valve was improved in this paper. And then well-cleaning packer equipped with flow path was developed. The new technology improves acid-cleaning performance and effectively enhances well productivity of screen completion horizontal wells. [ABSTRACT FROM AUTHOR]

Bullet compound perforation technology settled the problems existed in present compound perforation such as low utilization of bombing gun and gas, poor gas fracturing preference followed by perforation. Deviating from the other compound perforating technologies with high energy gas fracturing, bullet compound perforation realize near-well fracturing with blast wave caused by blasting bullet explosion in perforating channels. Technological mechanism, characteristics and index of bullet compound perforation technique were illustrated in this paper. The experiment show that the bullet compound perforation technology is valuable to enhance the productivity of oil & gas wells, and worth application and popularization. [ABSTRACT FROM AUTHOR]