The Comprehensive Technology of Horizontal Drilling And Development In Shengli Oilfield

Abstract

Abstract In the last few years, the horizontal drilling technology in Shengli Oilfield has developed at a rather rapid pace So far, 30 horizontal wells of different types have been completed in various hydrocarbon reservoirs. This paper emphasizes the design and drilling practices in the horizontal exploratory wells and the horizontal development wells of viscous oil gravel reservoirs in Shengli Oilfield The application and technology of horizontal well to other oil and gas reservoirs are also presented. Introduction Shengli Oilfield, the second largest oil and gas field in China, is a very important constituent part of Bohai bay oil and gas basin. Up to now, more than 20,000 wells have been drilled with accumulative oil production of 550 million tons. To stabilize the production, the urgent needs are to:explore new reservoirs;produce viscous oil;produce residue oil from the old fields;solve the water coning and production problems of low permeability reservoir. One of the best solution to the above is to drill horizontal wells. Shengli Oilfield began drilling horizontal wells in 1990. By the end of 1994, 30 horizontal wells had been drilled in the four different oil and gas reservoirs of six areas, with total footage of 54,295m, and horizontal interval of 10,429m in length. In four exploratory wells, the productive zone of 673. 9m in thickness have been found. The horizontal development wells were penetrated through productive zones with horizontal length of 9,000m. The total production of the completed wells amounts over 300,000 tons. The daily production for single well is generally higher than that of the nearby ordinary wells in the same area. This paper emphasizes the design and drilling practice in horizontal exploratory wells and horizontal development wells in viscous oil gravel reservoirs. HORIZONTAL EXPLORATORY WELLS From September, 1990 to September, 1993, four horizontal exploratory wells were drilled in the Northeast Slope of Chengdong Oilfield The formations in this areas are very special; the top portion is Shahejie formation and Guantao formation of the tertiary system overlapping layer by layer towards the protruding upper part longitudinally; the pre-Sinian system formation to Mesozoic erathem formation below the unconformity surface monoclinally dipped to NNE direction and were covered by mudstone of Guantao group to Dongying group. In such way the Permian system to Mesozoic erathem unconformity reservoirs were formed (Fig. 1). P. 79